JP7338953B2 - Sealing material sheet for self-luminous display and self-luminous display using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sealing material sheet for a self-luminous display and a self-luminous display using the same.

As next-generation display devices to replace various liquid crystal display devices, self-luminous display devices typified by micro LED televisions are being developed (Patent Document 1).

In this self-luminous display, a sealing material sheet for protecting the light-emitting element is laminated on the light-emitting surface side of the LED module in which the light-emitting element such as the LED element is mounted on the wiring board. (Patent Document 2).

Here, the sealing material sheet for electronic devices disclosed in Patent Document 2 is widely assumed to be applied to various electronic devices including solar cells, etc., and its Vicat softening point is 60 ° C. or less. , and particularly preferably in a low temperature range of 30 to 50°C or less. As described in the document, this is intended to "exhibit high adhesiveness by thermocompression bonding in a short period of time". Conventionally, the Vicat softening point is in the above low temperature range in order to ensure sufficient embedding (moldability) of the encapsulant sheet into the unevenness of the surface of electronic devices having various surface shapes. was considered preferable.

However, in the process of developing the above-described micro LED television, the surface of the electronic device to be covered with the sealing material sheet, for example, the light emitting surface of the LED module constituting the micro LED television. and the uniformity of the film thickness of the encapsulant after hot pressing is required to maintain image quality at a higher level than in the case of a solar cell module or the like. , a suspicion has arisen that a sealing material sheet having a Vicat softening point in the low temperature range as described above may not always be optimal.

When the target surface to be covered with the encapsulant sheet has minute unevenness, it is not necessary to limit the Vicad softening point to the low temperature range (60° C. or lower) as described above from the viewpoint of molding performance, and productivity is improved. In terms of aspects, rather than the above merit (that the thermocompression bonding can be completed in a short time) as described in Patent Document 2, total productivity and quality stability decrease due to blocking of the encapsulant sheet. is easier to manifest.

In addition, when the Vicat softening point of the encapsulant sheet is in the above low temperature range, it is necessary to add a cross-linking agent in order to ensure sufficient heat resistance of the encapsulant sheet, which increases the material cost of the encapsulant sheet. There are also problems such as an increase in the production temperature and a decrease in productivity due to restrictions on the film-forming temperature.

Under these circumstances, the development of a specialized encapsulant sheet suitable for various self-luminous display applications such as micro LED televisions, which are expected to become next-generation display devices, has been desired. .

JP 2018-14481 A JP 2014-148584 A

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a sealing material sheet that is particularly suitable for self-luminous displays such as micro LED televisions.

As a result of extensive research, the present inventors defined the Vicat softening point of the encapsulant sheet for electronic devices in a high temperature range different from the conventional one, and set the MFR to a specific low MFR range. The present inventors have found that by maintaining the above, the above problems can be solved, and a sealing material sheet that is particularly excellent in aptitude for a self-luminous display such as a micro LED television can be obtained. Specifically, the present invention provides the following.

(1) A resin sheet using an olefin resin as a base resin, having a Vicat softening point exceeding 60° C. and 90° C. or less, and an MFR at 190° C. of 0.1 g/10 min or more and 12.0 g/10 min. A sealing material sheet for a self-luminous display body, which is less than

In the invention of (1), in the sealing material sheet for sealing electronic devices, the Vicat softening point of the base resin is specified in a higher temperature range than the conventional product, and the MFR of the same resin is the same as before , or is maintained in a low MFR range below. According to this, blocking resistance in the manufacturing process of the encapsulant sheet, molding property during hot press processing, uniformity of film thickness after hot press processing, and suppression of resin extrusion due to excessive flow are all It is possible to obtain a sealant sheet of a particularly preferable level for a self-luminous display.

(2) The encapsulant sheet according to (1), which has an MFR at 190° C. of less than 5.0 g/10 min.

In the invention (2), the Vicat softening point temperature of the encapsulant sheet of (1) is kept within the above-mentioned high temperature range, while the MFR is further reduced. As a result, excessive flow of the encapsulant sheet (1) during hot press processing can be further suppressed, and the uniformity of the film thickness after hot press processing can be maintained at a higher level.

(3) The encapsulant sheet according to (2), which has an MFR at 190° C. of less than 0.5 g/10 min.

The invention of (3) suppresses the MFR to an extremely low range while maintaining the Vicat softening point temperature of the encapsulant sheet of (2) within the above-mentioned high temperature range. Such a sealing material sheet can be obtained by a so-called weak cross-linking treatment. As a result, excessive flow of the encapsulant sheet (1) during hot press processing can be further suppressed, and the uniformity of the film thickness after hot press processing can be maintained at an extremely high level.

(4) A light-emitting module for a self-luminous display, in which a plurality of light-emitting elements are mounted on a wiring board; and a display panel laminated on the surface of the sealing material sheet, wherein the sealing material sheet is the sealing material according to any one of (1) to (3). A self-luminous display that is a sheet.

According to the invention of (4), the advantageous effects of the sealing material sheet of any one of (1) to (3), such as blocking resistance, molding property, and film thickness uniformity, can be obtained. As a result, a self-luminous display having excellent productivity, durability, and optical properties can be obtained.

(5) The self-luminous display according to (4), wherein the light-emitting element is an LED element.

The invention (5) is an application of the present invention to various self-luminous LED display devices represented by micro LED televisions expected to be the mainstream of next-generation monitors. As a result, a self-luminous LED display device with excellent productivity, durability, and optical properties can be obtained.

(6) The LED element has an LED light-emitting chip and a resin cover covering the LED light-emitting chip, and the width and depth of the LED element are both 300 μm or less, and the height is 200 μm or less. The self-luminous display according to (5), wherein the LED elements are arranged at intervals of 0.03 mm or more and 12.0 mm or less.

The invention of (6) incorporates the self-luminous display body of (5) into a high-definition dot matrix display or the like in which LED elements are densely mounted by a chip-on-board method in which a large number of LED chips are directly mounted on a substrate. applied. As a result, it is possible to obtain a high-definition LED display device that is excellent in productivity, durability, and optical properties.

(7) The LED elements have a width and depth of 50 μm or less, a height of 10 μm or less, and an arrangement interval of the LED elements of 0.05 mm or more and 5 mm or less. ).

The invention of (7) applies the self-luminous display of (5) to a "micro LED television" which has been under development in recent years and is expected to be a next-generation image display device. As a result, it is possible to obtain an ultra-high-definition LED display device that is excellent in productivity, durability, and optical properties.

(8) Any one of (4) to (7), wherein a plurality of the light-emitting modules have a light-emitting surface formed by bonding on the same plane, and the sealing material sheet is laminated on the light-emitting surface. The self-luminous display body according to 1.

The invention of (7) joins a plurality of LED modules for a self-luminous display configured using the sealing material sheet of (1) or (2), and various self-luminous types including micro LED televisions. This is to increase the screen size of the display. Since the sealing material sheet of (1) or (2) has excellent surface smoothness after bonding by thermal lamination, it does not cause deterioration of screen quality due to bonding of the above module, and can be used as a self-luminous display. It is possible to flexibly increase the size of the screen.

ADVANTAGE OF THE INVENTION According to this invention, the sealing material sheet especially preferable for various self-luminous display applications, such as a micro LED television, can be provided.

1 is a plan view and a partially enlarged plan view of an image display surface of a self-luminous display body in which a sealing material sheet of the present invention is laminated on a light-emitting module (LED module) for the self-luminous display body; FIG. FIG. 2 is a cross-sectional view showing a cross section taken along line AA of FIG. 1; 2 is a perspective view of an LED element that constitutes the LED module for the self-luminous display of FIG. 1; FIG.

<Self-luminous display>
First, the "self-luminous display" in this specification is a display device typified by the micro LED television exemplified above, and is a display device for visual information such as characters, images, and moving images. In this display device, a large number of minute light-emitting elements are mounted in a matrix on a wiring board, and the light-emitting elements are selectively caused to emit light by means of light emission control means connected thereto, thereby displaying the above visual information. This is a display device that can directly display on a display screen by blinking light-emitting elements.

The sealing material sheet for a self-luminous display body of the present invention (hereinafter also simply referred to as "sealing material sheet") is an LED display using an LED element as a light-emitting element among "self-luminous display bodies". It can be particularly preferably used for the device. Moreover, it is more preferable that the LED element in this case is a "miniature LED element". In this specification, the term “miniature LED element” specifically refers to the size of the entire light-emitting element including the LED light-emitting chip and the resin cover that covers the light-emitting element, and the width (W) and depth (D ) is 300 μm or less, and the height (H) is 200 μm or less (see FIG. 3).

Further, as for the size of this "micro-sized LED element", it is more preferable that both the width and the depth are 50 μm or less and the height is 10 μm or less. This size range is the standard size of LED elements mounted on micro LED televisions, which have been developed in recent years and are expected to become the mainstream of next-generation televisions. Hereinafter, in this specification, the width and depth are both 50 μm or less, and the height is 10 μm or less. A self-luminous display having a certain number or more arranged in a matrix is called a “micro LED display device”.

In the following, an embodiment in which the "self-luminous display" is a "micro LED display device" is taken up as a particularly preferred specific example among the various embodiments of the present invention. A detailed description of However, the technical scope of the present invention is not limited to application only to the "micro LED display device". This technique is also applicable to the general “self-luminous display” defined above.

[Micro LED display device]
FIG. 1 is a front view and a partially enlarged view (100A) of a micro LED display device 100, which is an embodiment of the self-luminous display of the present invention. FIG. 2 is a cross-sectional view showing a cross section taken along line AA of FIG. 1, and is a drawing for explaining the layer structure of the micro LED display device 100 shown in FIG. This micro LED display device 100 is a self-luminous display device provided with an LED module 30, which is a light-emitting module for a self-luminous display, in which a large number of micro-sized LED elements 10 are mounted on a wiring board 20 as light-emitting elements. The light emission of each LED element 10 is individually controlled by light emission control means (not shown) such as an IC chip substrate that is separately bonded.

Further, in the micro LED display device 100 , the sealing material sheet 1 for a self-luminous display body is laminated on the mounting surface of the LED element 10 of the LED module 30 in such a manner as to cover the LED element 10 . A display surface panel 2 such as various optical films and transparent protective glass is further laminated on the outer surface side of the sealing material sheet 1 (the display surface side in the micro LED display device 100).

Further, a plurality of self-luminous display LED modules 30 are bonded in a matrix on the same plane, and the sealing material sheet 1 is laminated on the bonded LED modules in the same manner as described above, thereby forming a large self-luminous display. An LED module for a light-emitting type display and a large-sized micro LED display device can be constructed. In this case, the excellent uniformity of the film thickness of the encapsulant sheet 1 after hot-pressing maintains the uniformity of the display surface at the joints between the individual LED modules to be joined. It also contributes to the improvement of the image quality of the micro LED display device.

(Manufacturing method of micro LED display device)
The micro LED display device 100 includes an LED module 30 for a self-luminous display formed by mounting an LED element 10 on a wiring board 20, a sealing material sheet 1, a display surface panel 2, and, if necessary, It is possible to produce a laminate by laminating other optical members such as the above, and integrating this laminate by hot pressing. In addition, it is preferable that some of the laminated members are previously bonded with an adhesive before the above-mentioned hot press processing, if necessary. The encapsulant sheet 1 of the present invention exhibits sufficient molding properties during hot press processing for integration as the final product, and is extremely excellent in uniformity of film thickness after this hot press processing. characterized by

(LED module for self-luminous display)
As shown in FIG. 2, an LED module 30, which is a light-emitting module for a self-luminous display according to the present invention, has an LED element 10 mounted on a wiring substrate 20 having a wiring portion 22 formed on a support substrate 21. Consists of

As shown in FIG. 2, the wiring board 20 has a wiring part 22 formed on the surface of a supporting substrate 21 in such a manner that it can be electrically connected to the LED element 10. The wiring part 22 is made of metal such as copper or other conductive material. It is a circuit board that consists of The support substrate 21 may be a conventionally known hard glass epoxy substrate as a substrate for electronic circuits, or may be made of a flexible resin such as polyethylene terephthalate, polyimide, or polyethylene naphthalate.

In the LED module 30, as shown in FIG. 2, the LED element 10 is mounted on the wiring portion 22 via the solder layer 23 in a conductive manner.

The size of the LED module 30 is not particularly limited, but a diagonal length of about 50 inches to 200 inches is generally preferred from the viewpoint of cost performance. Further, as described above, a plurality of LED modules 30 for a self-luminous display are joined in a matrix on the same plane to form a light-emitting surface of a self-luminous display such as the large-sized micro LED display device 100. can do. For example, 100×100 LED modules 30 with a diagonal length of 6 inches can be joined vertically and horizontally to form a micro LED television with a large screen with a diagonal length of 600 inches.

(LED element)
The LED element 10 that is mounted on the wiring board 20 and constitutes the LED module 30 for a self-luminous display is a light-emitting element that utilizes light emitted from a PN junction where a P-type semiconductor and an N-type semiconductor are joined. A structure in which a P-type electrode and an N-type electrode are provided on the top and bottom surfaces of the element and a structure in which both the P-type and N-type electrodes are provided on one side of the element have been proposed. Although the LED element 10 of any structure can be used in the LED display device 100 of the present invention, a micro-sized LED element such as the LED element disclosed as a "chip-shaped electronic component" in Japanese Patent Application Laid-Open No. 2006-339551 can be used. An LED element can be used particularly preferably. The LED element disclosed in the document is said to have a width×depth×height size of approximately 25 μm×15 μm×2.5 μm.

The LED element 10 preferably includes an LED light-emitting chip 11 and a resin cover 12 covering it. As the resin cover 12, organic insulating materials such as epoxy resin, silicon resin, polyimide resin, etc. are used, and among these, epoxy resin is particularly preferably used. The resin cover 12 made of epoxy resin not only protects the LED light-emitting chip 11 from physical impact, but also protects the inside of the semiconductor due to the difference in refractive index between the semiconductor constituting the LED light-emitting chip 11 and air. This is because it also plays a role of suppressing total reflection of light and increasing the luminous efficiency of the LED element 10 . The encapsulating material sheet 1 is preferable as an encapsulating material to be mounted on the micro LED display device 100 in that it is made of an olefin-based resin having excellent adhesion to epoxy resin.

In the self-luminous display of the present invention, an LED element comprising an LED light-emitting chip and a resin cover covering the LED element has a width and depth of 300 μm or less and a height of 200 μm or less. sized LED elements can be preferably used. In this case, the arrangement interval of the LED elements is preferably 0.03 mm or more and 100 mm or less.

Further, in the self-luminous display of the present invention, the LED element includes an LED light-emitting chip and a resin cover covering it, and the width and depth are both 50 μm or less, and the height is 50 μm or less. It is more preferable to use an LED element having a very small size of 10 μm or less. In this case, the arrangement interval of the LED elements is preferably 0.03 mm or more and 100 mm or less. Such a mounting manner of the LED element is also a standard mounting manner of the LED element specifically in the micro LED television.

(Sealant sheet for self-luminous display)
The encapsulant sheet of the present invention is a resin sheet that can be particularly preferably used as a resin sheet that covers a large number of minute light-emitting elements and is laminated on a wiring board in a "self-luminous display". Further, the encapsulant sheet for the self-luminous display body is formed into a sheet-like member by forming a film of an encapsulant composition having an olefin resin as a base resin. The encapsulant sheet of the present invention may be a single-layer film, or may be a multi-layer film composed of a core layer and skin layers arranged on both sides of the core layer. The term "multilayer film" as used herein refers to a film or sheet having a structure having a skin layer formed on at least one of the outermost layers, preferably both outermost layers, and a core layer other than the skin layer. Say things.

The thickness of the encapsulant sheet may be 50 μm or more and 1000 μm or less, preferably 50 μm or more and 500 μm or less, and more preferably 50 μm or more and 300 μm or less. Moreover, when the LED element to be covered is an LED element of extremely small size with a height of 10 μm or less, the thickness of the encapsulant sheet is preferably 25 μm or more and 100 μm or less. When the thickness of the encapsulant sheet is 50 μm or more, the LED elements can be sufficiently protected from external impact. On the other hand, when the thickness of the encapsulant sheet is 1000 μm or less, sufficient molding properties can be exhibited. Specifically, when the LED element is covered with heat press, the resin forming the encapsulant sheet sufficiently wraps around the irregularities on the surface of the LED module, so that good lamination without gaps can be performed. . Moreover, in the integrated self-luminous display body, the light transmittance of the sealing layer made of the sealing material sheet can be sufficiently ensured.

The encapsulant sheet has a Vicat softening point of more than 60° C. and 90° C. or less, preferably 70° C. or more and 90° C. or less. By setting the Vicat softening point of the encapsulant sheet to more than 60°C, the occurrence of blocking in the manufacturing process of the self-luminous display using the encapsulant sheet is suppressed, and the productivity of the self-luminous display is improved. can contribute to improvement. Further, by setting the temperature range to 90° C. or less, it is possible to maintain the molding property required for the sealing material sheet for the self-luminous display.

Moreover, it is preferable to optimize the Vicat softening point of the encapsulant sheet more precisely according to the melting point of the encapsulant sheet. Specifically, when the melting point of the encapsulant sheet is in a relatively low range of 50° C. to less than 70° C., the Vicat softening point is set to 60° C. to 70° C. in order to suppress excessive flow during hot press processing. A range of less than is preferable. Also, when the melting point is in a relatively high range of 70° C. or higher, the Vicat softening point is preferably in the range of 70° C. to 90° C. in order to maintain good molding properties during hot press working.

In addition, the "Vicat softening point" of the encapsulant sheet in the present specification is a encapsulant obtained by forming a encapsulant composition containing a resin component and other additives into a sheet by a molding method such as extrusion melt molding. It refers to the value of the Vicat softening point measured in accordance with ASTM D1525 at the stage after sheeting is completed.

Further, the sealing material sheet for a self-luminous display body has a melt mass flow rate (MFR) at 190 ° C. of the resin sheet constituting it of 0.1 g / 10 min or more and less than 12.0 g / 10 min, preferably , 0.1 g/10 min or more and less than 5.0 g/10 min, more preferably 0.1 g/10 min or more and less than 0.5 g/10 min. By setting the MFR of the encapsulant sheet to 0.1 g/10 min or more, it is possible to provide the molding property required for the encapsulant sheet for a self-luminous display.

Further, by setting the MFR to less than 12.0 g/10 min, the film thickness uniformity of the encapsulant sheet after hot pressing for integration as a self-luminous display device can be maintained at an extremely high level. can be done. In a self-luminous display such as the micro LED display device 100, the encapsulant sheet laminated on the light emitting surface side of the LED element is required to have a particularly uniform thickness. This is because even a slight difference in film thickness between the center portion and the bottom portion of the encapsulant sheet causes the encapsulant sheet to be in a lens-like state, undesirably affecting the display quality of the micro LED display device. because it gives.

In addition, when the MFR of the encapsulant sheet is less than 12.0 g/10 min, the flowability of the material resin composition is reduced, and there is also the advantage that high-temperature film formation becomes possible during sheet extrusion molding, thereby improving productivity. . Film formation at a high temperature makes it possible to lower the torque of the extruder, making sheet molding easier. In addition, in the case of film formation at high temperature, it is possible to suppress neck-in during sheet molding and form a wide sheet. It is difficult to generate unevenness on the surface of the sheet, and it is easy to obtain a good appearance.

If the MFR of the encapsulant is 12.0 g/10 min or more, it is necessary to use a cross-linking agent or the like for cross-linking in order to provide heat creep resistance. If the sealing material has an MFR of less than 12.0 g/10 min, no cross-linking prescription is required, and the press conditions can be set in common. Also from these points, it is preferable that the MFR of the encapsulant sheet is less than 12.0 g/10 min.

In addition, the "MFR" of the encapsulant sheet in this specification is a encapsulant sheet obtained by forming a encapsulant composition containing a resin component and other additives into a sheet by a molding method such as extrusion melt molding. It refers to the value of the MFR at the stage after the completion of sheeting, measured under the conditions of 190° C. and a load of 2.16 kg in accordance with JIS K7210. Regarding the MFR when the encapsulant sheet is a multilayer film, the measurement is performed by the above process while all the layers are laminated together in a multilayer state, and the obtained measured value is used for the multilayer encapsulant sheet. shall be the MFR value.

As the base resin of the encapsulant composition forming the encapsulant sheet, a wide range of olefinic thermoplastic resins can be selected as long as the Vicat softening point and MFR are within the above ranges. Among them, polyethylene-based resins such as low-density polyethylene resin (LDPE), linear low-density polyethylene resin (LLDPE), or metallocene-based linear low-density polyethylene resin (M-LLDPE) can be preferably used. In the present specification, the term "base resin" refers to a resin having the largest content ratio among the resin components of the resin composition containing the base resin.

The density of the polyethylene resin used as the base resin of the encapsulant composition should be 0.870 g/cm ³ or more and 0.910 g/cm 3 or less, preferably 0.895 g/cm ³ or more and 0.895 g/cm ³ or more. 905 g/cm ³ or less. By setting the density of the base resin of the encapsulant composition to 0.910 g/cm ³ or less, the adhesion of the encapsulant sheet to the wiring board or the like can be maintained within a preferable range. Further, by setting the density to 0.890 g/cm ³ or more, the encapsulant sheet can be provided with necessary and sufficient heat resistance without cross-linking treatment.

Here, one of the characteristics of the encapsulant sheet of the present invention is that it is a thermoplastic encapsulant that does not require cross-linking treatment after film formation. As the encapsulant sheet, a "weakly cross-linked encapsulant" obtained by weakly cross-linking a polyethylene-based encapsulant composition can also be used. "Weakly cross-linked" is a cross-linking treatment technology related to the method for manufacturing a sealing material, the details of which are disclosed in International Publication No. WO 2011/152314. is a technique of forming a film of the encapsulant composition while proceeding. In this specification, the weakly crosslinked sealing material formed through the weakly crosslinking treatment is referred to as a "weakly crosslinked sealing material". The weak cross-linking sealant has undergone a weak cross-linking treatment at the time of film formation, and substantially no cross-linking agent remains after film formation. Therefore, no separate cross-linking treatment is required during the manufacturing process of the self-luminous display.

This weakly cross-linked sealing material uses a polyethylene resin with a density of 0.870 g/cm ³ or more and 0.890 g/cm ³ or less as a base resin, and contains a very small amount of cross-linking agent. The sealing material composition can be obtained by performing the above-described weak cross-linking treatment during film formation in the process of forming a film by a conventionally known method.

A silane copolymer obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as comonomers (hereinafter also referred to as "silane-modified polyethylene-based resin") is optionally added to the sealing material composition. , it is more preferable to contain a certain amount in each encapsulant composition. The silane-modified polyethylene-based resin is obtained by graft-polymerizing an ethylenically unsaturated silane compound as a side chain to a linear low-density polyethylene-based resin (LLDPE) or the like that serves as a main chain. Such a graft copolymer increases the degree of freedom of the silanol groups that contribute to adhesive strength, and thus can improve the adhesiveness of the encapsulant sheet 1 to other members in the solar cell module. The content of the silane-modified polyethylene-based resin in the encapsulant composition is 2% by mass or more and 20% by mass or less in the core layer encapsulant composition, and in the skin layer encapsulant composition, It is preferably 5% by mass or more and 40% by mass or less. In particular, it is more preferable that the sealant composition for the skin layer contains 10% or more of silane-modified polyethylene. The silane-modified amount in the silane-modified polyethylene-based resin is preferably about 1.0% by mass or more and 3.0% by mass or less. The preferable content range of the silane-modified polyethylene-based resin in the sealing material composition is based on the premise that the amount of silane modification is within this range, and fine adjustments may be made as appropriate according to fluctuations in the amount of modification. is desirable.

The silane-modified polyethylene resin can be produced, for example, by the method described in JP-A-2003-46105. By using the resin as a component of a sealing material composition for solar cell modules, strength and durability can be improved. etc., and also excellent in weather resistance, heat resistance, water resistance, light resistance, wind pressure resistance, hail resistance, and other various characteristics. It is possible to stably manufacture a solar cell module suitable for various uses at a low cost, which has extremely excellent heat-sealability without any defects.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples.

<Production of encapsulant sheet for self-luminous display>
The following encapsulant composition prepared for each example and comparative example was extruded at a temperature of 210° C. and a take-up speed of 1.1 m/min using a film forming machine having a φ30 mm extruder and a T die with a width of 200 mm. , and formed into a sheet with a film thickness of 400 μm to produce a sealing material sheet for each example and comparative example. As for the cooling roll directly below the T-die and the rubber roll, the cooling roll used was a chrome-plated cooling roll with a surface roughness Rz of 1.5 μm, and the rubber roll used was a silicone rubber roll with a hardness of 70 degrees.

(Sealing material sheet of Example 1 (1-1 to 1-2))
100 parts by mass of base resin 1 below, 5 parts by mass of additive resin 1 (weather resistant agent masterbatch) and 20 parts by mass of additive resin 2 (silane-modified polyethylene resin) below are mixed. 1 (1-1 to 1-2) as encapsulant compositions for molding encapsulant sheets.
Base resin 1
: A metallocene linear low-density polyethylene resin (M-LLDPE) having a density of 0.901 g/cm ³ , a melting point of 93°C and an MFR of 2.0 g/10 min at 190°C.
Additive resin 1 (weather resistant agent masterbatch)
: KEMISTAB62 (HALS): 0.6 parts by mass with respect to 100 parts by mass of a low-density polyethylene resin having a density of 0.919 g/cm ³ and an MFR of 3.5 g/10 minutes at 190°C. KEMISORB12 (UV absorber): 3.5 parts by mass. KEMISORB79 (UV absorber): 0.6 parts by mass.
Additive resin 2 (silane-modified polyethylene resin)
: ² parts by mass of vinyltrimethoxysilane and a radical generator (reaction A silane-modified polyethylene resin obtained by mixing 0.15 parts by mass of dicumyl peroxide as a catalyst), melting and kneading at 200°C. The added resin 2 has a density of 0.901 g/cm ³ and an MFR of 1.0 g/10 minutes.

(Sealing material sheet of Example 2 (2-1 to 2-2))
100 parts by mass of the following base resin 2, 5 parts by mass of the above additive resin 1 (weather resistant masterbatch), and 20 parts by mass of the above additive resin 2 (silane-modified polyethylene resin) are mixed, It was used as a sealing material composition for molding the sealing material sheet of Example 2 (2-1 to 2-2).
Base resin 2: A metallocene-based linear low-density polyethylene resin (M-LLDPE) having a density of 0.898 g/cm ³ and an MFR of 3.5 g/10 min at 190°C.

(Sealing material sheet of Example 3 (3-1 to 3-2))
100 parts by mass of the following base resin 3, 5 parts by mass of the above additive resin 1 (weather resistant agent masterbatch), and 20 parts by mass of the above additive resin 2 (silane-modified polyethylene resin) are mixed, It was used as a sealing material composition for molding the sealing material sheet of Example 3 (3-1 to 3-2).
Base resin 3: A metallocene-based linear low-density polyethylene resin (M-LLDPE) having a density of 0.905 g/cm ³ and an MFR of 3.5 g/10 min at 190°C.

(Sealing material sheet of Example 4 (4-1 to 4-2))
100 parts by mass of the base resin 4 below, 5 parts by mass of the above additive resin 1 (weather resistant agent masterbatch), and 20 parts by mass of the above additive resin 2 (silane-modified polyethylene resin) are mixed, It was used as a sealing material composition for molding the sealing material sheet of Example 4 (4-1 to 4-2).
Base resin 4: A metallocene-based linear low-density polyethylene resin (M-LLDPE) having a density of 0.919 g/cm ³ and an MFR of 3.5 g/10 min at 190°C.

(Sealing material sheet of Example 5 (5-1 to 5-2))
Based on 97 parts by mass of the base resin 5 below, 5 parts by mass of the above additive resin 1 (weather resistant masterbatch 1-2) and 5 parts by mass of the above additive resin 2 (silane-modified polyethylene resin). They were mixed to obtain a sealing material composition for molding the sealing material sheet of Example 5 (5-1 to 5-2), which is a weakly crosslinked sealing material sheet.
Base resin 5: 2,5-dimethyl-2,5-di(t-butyl per 100 parts by mass of M-LLDPE pellets having an MFR of 3.5 g/10 min at 0.880 g/cm ³ at 190°C. Compound pellets obtained by impregnating 0.041 parts by mass of oxy)hexane.

<Production of sealing material>
EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples. The invention is not limited to the following examples.

(Sealant sheet of Comparative Example 1 (1-1 to 1-2))
100 parts by mass of the base resin 6 below, 5 parts by mass of the additive resin 1 (weather resistant agent masterbatch), and 20 parts by mass of the additive resin 2 (silane-modified polyethylene resin) are mixed, It was used as a sealing material composition for molding the sealing material sheet of Comparative Example 1 (1-1 to 1-2).
Base resin 6: A metallocene-based linear low-density polyethylene resin (M-LLDPE) having a density of 0.880 g/cm ³ and an MFR of 2.2 g/10 min at 190°C.

(Sealant sheet of Comparative Example 2)
100 parts by mass of the base resin 7 below, 3 parts by mass of the additive resin 1 (weather resistant agent masterbatch), and 10 parts by mass of the additive resin 2 (silane-modified polyethylene resin) are mixed, A sealing material composition for molding the sealing material sheet of Comparative Example 2 was prepared.
Base resin 7: A metallocene-based linear low-density polyethylene resin (M-LLDPE) having a density of 0.910 g/cm ³ and an MFR of 15.0 g/10 min at 190°C.

(Sealant sheet of Comparative Example 3)
100 parts by mass of the base resin 8 below, 5 parts by mass of the above additive resin 1 (weather resistant agent masterbatch), and 20 parts by mass of the above additive resin 2 (silane-modified polyethylene resin) are mixed, A sealing material composition for molding the sealing material sheet of Comparative Example 2 was prepared.
Base resin 8: Metallocene-based linear low-density polyethylene resin (M-LLDPE) having a density of 0.913 g/cm ³ and an MFR of 2.4 g/10 min at 190°C.

<Vicat softening point of sealing material sheet>
The Vicat softening point of each encapsulant sheet of Examples and Comparative Examples was measured according to ASTM D1525. Table 1 shows the results.

<MFR of sealing material sheet>
The MFR of each encapsulant sheet of Examples and Comparative Examples was measured under conditions of 190° C. and a load of 2.16 kg according to JIS K7210. Table 1 shows the results.

<Evaluation Example 1: Blocking resistance>
The blocking resistance of each encapsulant sheet of Examples and Comparative Examples was evaluated by the following test method.
[Blocking resistance test]
(Test method)
The blocking properties of each encapsulant sheet of Examples and Comparative Examples were measured according to ASTM D395 using a blocking tester of CO-201 permanent strain tester (constant load type) manufactured by Tester Sangyo Co., Ltd. A load of 5 kg is applied using a large test piece of 29 mmφ, and the cooling roll surface side and the rubber roll surface side during film formation are aligned. It was sandwiched between two layers, placed in a moist heat oven at 40°C and 90% heat for 48 hours, and then blocked at 23°C and 50% after 24 hours.
(Evaluation criteria)
A: Peeled off without applying force.
B: When peeling, it peeled by applying force.
C: It was observed that a force was applied during peeling, and as a result of the peeling, part of one sealing material laminated on the peeled surface was dislocated to the other and adhered to the other.
The evaluation results are shown in Table 1 as "blocking resistance".

<Evaluation Example 2: Moldability>
The sealing material sheets of Examples and Comparative Examples were evaluated for molding properties on various uneven surfaces by the following test methods.
[Creation of module for moldability test]
Sample 1 (denoted as "fine" in the table of module irregularities in Table 1)
: Prepare an LED module in which micro-sized LED elements of width 25 μm×depth 15 μm×height 2.5 μm are arranged at a pitch of 2 mm on the surface of a glass epoxy wiring board of size 200×300 mm. A 300-μm-thick sealing material sheet of any of the Examples and Comparative Examples was laminated on the arrangement surface, and a 50-μm-thick ethylene tetrafluoroethylene sheet having a single-sided corona treatment was applied as a surface protection film on the sealing material sheet. A fluoroethylene (ETFE) film is laminated, and vacuum lamination is performed using a vacuum laminator for solar cell module manufacturing under the conditions of a temperature of 150°C, a vacuum drawing time of 5 minutes, a press holding time of 10 minutes, and an upper chamber pressure of 70 KPa. , a moldability test module (Sample 1) was produced.
Sample 2 (denoted as "small" in the module unevenness list in Table 1)
: A module for moldability test ( Sample 2) was produced.
[Moldability test]
Each of the test modules described above was visually observed, and the molding properties were evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: The encapsulant sheet completely conforms to the unevenness of the LED element arrangement surface facing each other. No void formation was observed.
B: No more than 3 bubbles within 2 mm ² were observed.
C: A part of the encapsulant sheet does not completely follow the unevenness of the facing LED element arrangement surface, and the LED
A partial lamination failure portion (void) was formed in the vicinity of the element.
The evaluation results are shown in Table 1 as "moldability".

<Evaluation Example 3: Film thickness uniformity>
Regarding the sealing material sheets of Examples and Comparative Examples, the film thickness uniformity after vacuum lamination in the molding test was evaluated by the following test method using each of the above test modules. was measured and evaluated.
[Film thickness uniformity test]
50 μm untreated ETFE was laminated as a release film on the front and back of each sealing material sheet of Examples and Comparative Examples cut to 30 × 30 cm, and then glass of 30 × 30 cm and a thickness of 3 mm was further laminated on the front and back. This laminate was vacuum laminated under the same conditions as in Evaluation Example 2. After cooling, the glass and ETFE were peeled off, and the thickness of the encapsulating material was measured at two points, the center portion and the point 2 cm from the corner toward the center, using a digital film thickness meter, and evaluated as follows. The film thickness uniformity was evaluated according to the standard.
(Evaluation criteria)
A: The film thickness difference between the central portion and the portion 2 cm from the corner is less than 12 microns (3%).
B: The film thickness difference between the central portion and the portion 2 cm from the corner is 12 microns (3%) or more and less than 32 microns (8%).
C: The film thickness difference between the central portion and the portion 2 cm from the corner is 32 microns (8%) or more.
The evaluation results are shown in Table 1 as "film thickness uniformity".

From Table 1, it can be seen that the encapsulant sheet of the present invention has sufficient molding properties for fine uneven surfaces and excellent film thickness uniformity. It turns out that it is suitable.

REFERENCE SIGNS LIST 1 sealing material sheet 2 display surface panel 10 LED element 11 LED light-emitting chip 12 resin cover 20 wiring substrate 21 support substrate 22 wiring portion 23 solder layer 30 LED module for self-luminous display 100, 100A, 100B Micro LED display device (Self-luminous display)

Claims (7)

a light-emitting module for a self-luminous display in which a plurality of light-emitting elements are mounted on a wiring substrate;
a sealing material that covers the light emitting element and is directly laminated on the mounting surface side of the light emitting element of the wiring substrate;
a display surface panel directly laminated on the surface of the sealing material opposite to the surface covering the light emitting element ,
The sealing material is
A resin sheet containing an olefin-based resin as a base resin, having a Vicat softening point exceeding 60°C and not exceeding 90°C, and an MFR at 190°C of not less than 0.1 g/10 min and less than 12.0 g/10 min. , A sealing material sheet for a self-luminous display (excluding those with a thickness of 100 μm or less),
Self-luminous display. The self-luminous display according to claim 1 , wherein the sealing material sheet has an MFR at 190°C of less than 5.0 g/10 min. The self-luminous display according to claim 2 , wherein the encapsulant sheet has an MFR at 190°C of less than 0.5 g/10 min. 4. The self-luminous display according to any one of claims 1 to 3 , wherein said light emitting element is an LED element. The LED element has an LED light-emitting chip and a resin cover covering the LED light-emitting chip,
The width and depth of the LED element are both 300 μm or less, and the height is 200 μm or less,
5. The self-luminous display according to claim 4 , wherein the LED elements are arranged at intervals of 0.03 mm or more and 100 mm or less. The width and depth of the LED element are both 50 μm or less, and the height is 10 μm or less,
6. The self-luminous display according to claim 5 , wherein the LED elements are arranged at intervals of 0.05 mm or more and 5 mm or less. 7. The self-luminescence according to any one of claims 1 to 6 , wherein a plurality of said light-emitting modules have light-emitting surfaces joined on the same plane, and said encapsulant sheet is laminated on said light-emitting surfaces. Type indicator.

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