JP2023088914A - Self-light emitting type display body - Google Patents

Abstract

To simplify a layer structure of a self-light emitting type display body including a light shielding layer more than that of a conventional self-light emitting type display body.SOLUTION: A plurality of light emitting elements 10 includes: a light emitting module 30 formed by being mounted on a wiring board 20: a black sealing material sheet 1 using an olefin-based resin as a base resin; and a transparent optical layer 2. Disclosed is a self-light emitting type display body 100 in which the black sealing material sheet 1 covers the surface of the light emitting element and the wiring board 20, and is laminated on the light emitting module 30 and the transparent optical layer 2 is laminated on the black sealing material sheet 1.SELECTED DRAWING: Figure 2

Description

The present invention relates to a self-luminous display. More specifically, the present invention relates to a self-luminous display represented by a micro LED television, which has a simpler layer structure than conventional self-luminous displays due to its own design concept.

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

In this self-luminous display, a transparent sealant sheet for protecting the light-emitting element is provided 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. It is laminated (see Patent Document 2).

In many self-luminous display bodies, a light-shielding layer made of a black resin film or the like containing a material that absorbs visible light is further laminated on the transparent sealing material sheet (see Patent Document 3). ). The light-shielding layer is arranged to prevent the light reflected from the substrate or the like on which the light-emitting element serving as the light source is mounted in the self-luminous display body from adversely affecting the quality of the displayed image. .

JP 2018-14481 A JP 2014-148584 A JP 2015-197543 A

An object of the present invention is to simplify the layer structure of a self-luminous display including a light shielding layer as compared with the conventional self-luminous display.

The present inventors, based on their own design concept, replaced the transparent sealing material placed on the substrate on which the light-emitting element serving as the light source was mounted in the conventional self-luminous display with a black sealing material. The present invention has been completed based on the idea that the layer structure of a self-luminous display including a light-shielding layer can be simplified more than before. Specifically, the present invention provides the following.

(1) A light-emitting module in which a plurality of light-emitting elements are mounted on a wiring board, a black sealing material sheet using an olefin resin as a base resin and having a visible light transmittance of 5% or more and 70% or less, and a transparent optical layer , wherein the black encapsulant sheet covers the surfaces of the light emitting element and the wiring board and is laminated on the light emitting module, and the transparent optical layer is laminated on the black encapsulant sheet A self-luminous display body.

According to the invention (1), the layer structure of the self-luminous display including the light shielding layer can be simplified as compared with the conventional self-luminous display. As a result, it is possible to improve the productivity of the self-luminous display represented by the micro LED television.

(2) The black pigment contained in the black encapsulant sheet is carbon black, and the content of the carbon black in the resin component of the black encapsulant sheet is 0.0001% by mass or more and 0.0001% by mass or more. 08% by mass or less of the self-luminous display according to (1).

In the invention of (2), the content of carbon black in the resin component of the black encapsulant sheet is 0.0001% by mass or more, whereby stable and sufficiently less uneven coloring is possible, On the other hand, when the content is 0.08% by mass or less, it is possible to transmit LED light with an appropriate transmittance.

(3) The black encapsulant sheet contains a dispersant made of one or more kinds of metal soaps, and the content of the dispersant in the resin component of the black encapsulant sheet is 0.5. The self-luminous display according to (1) or (2), which is 00001% by mass or more and 0.002% by mass or less.

In the invention of (3), when a black sheet having transparency with a visible light transmittance of 5% or more is formed, it is essential to increase the dispersibility of the pigment, but within the above range, By adding a dispersant, it is possible to sufficiently improve the dispersibility of the pigment while preventing slippage of the screw during film formation.

(4) The supporting substrate of the wiring substrate is a glass epoxy hard substrate, and the color of the surface of the supporting substrate on the LED element mounting surface side is colored other than white and black (1) to (3). The self-luminous display body according to any one of 1.

The invention of (4) provides a self-luminous display such as a micro LED display device using a colored glass epoxy substrate, typically brown, as a supporting substrate, wherein the supporting substrate disposed inside is, for example, brown. It is possible to effectively reduce deterioration in display quality due to reflected light from the substrate, which is particularly likely to be a problem in the case of a colored surface such as a system.

(5) The self-luminous display according to any one of (1) 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. This makes it possible to obtain a self-luminous LED display device that is more productive than conventional products.

(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 100 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. Thereby, a high-definition LED display device with excellent productivity can be obtained.

(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 with excellent productivity.

According to the present invention, the layer structure of a self-luminous display body including a light shielding layer can be simplified more than conventional self-luminous display bodies, and various self-luminous display bodies such as micro LED televisions can be used. It can contribute to the improvement of the productivity of the display body.

1A and 1B are a plan view and a partially enlarged plan view of an image display surface for a self-luminous display of the present invention; FIG. FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, and schematically shows the layer structure of the self-luminous display of the present invention. FIG. 2 is a diagram schematically showing the layer structure of a black encapsulant sheet according to the present invention that constitutes the self-luminous display body 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. FIG. 3 is a diagram schematically showing the layer structure of a conventional self-luminous display.

<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.

In particular, the "self-luminous display" of the present invention can be preferably implemented as an LED display device using LED elements as light emitting elements. 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. 4).

Further, as for the size of this "micro-sized LED element", it is more preferable that both the width and depth are 50 μm or less and the height is 10 μm or less. This size range is the standard size range 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 device in which more than a certain number of self-luminous display members are 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 explanation 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 in FIG. 1, and is a drawing for explaining the layer structure of the micro LED display device 100 (100B) shown in FIG. This micro LED display device 100 (100B) 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 substrate 20 as "light-emitting elements". It is a self-luminous display device provided with an LED module 30". 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.

In the micro LED display device 100 (100B), as shown in FIG. 2, the mounting surface of the LED element 10 of the LED module 30 is coated with the LED element 10, and the visible light transmittance is 5% or more and 70% or less. A black encapsulant sheet 1, which is a resin sheet, is laminated. Further, the black encapsulant sheet 1 is laminated on the LED module (light emitting module) 30 in close contact with the top surface and all side surfaces of the LED element (light emitting element) 10 and the surface of the wiring substrate 20. is preferred. Since the black encapsulant sheet 1 is in close contact with the side surfaces of the LED element 10 due to its excellent molding properties, it is possible to emit light from the side surface, especially when the LED element is of a type that also emits light from the side surface. It is possible to prevent a display having poor color reproducibility due to loss of color balance due to light being irradiated onto a glass epoxy substrate and the color of the substrate being reflected and leaking from the surface of the display. Further, in the light-emitting module disclosed in Patent Document 3, through holes are formed in the light-shielding layer directly above the LED elements. A light-shielding layer having no openings can be applied in order to enable bright light emission and improve color reproducibility. The details of the composition, layer structure, etc. of the black encapsulant sheet 1 will be described later.

In the micro LED display device 100 (100B), as also shown in FIG. display surface side).

Here, as disclosed in Patent Document 3 and the like, in the conventional micro LED display device 100C, as shown in FIG. A light-shielding layer 4 was separately arranged on the surface thereof with an adhesive layer 3A interposed therebetween. A transparent optical layer 2 similar to that described above is further laminated on the surface of the light shielding layer 4 with an adhesive layer 3B interposed therebetween.

On the other hand, in the micro LED display device 100 (100B) (see FIG. 2) of the present invention, the LED element protection function of the sealing material 1C in the conventional micro LED display device 100C shown in FIG. and the optical functions are assumed only by the black sealing material sheet 1, thereby simplifying the layer structure of the entire display device while maintaining each function of the conventional product.

In the present invention, a plurality of self-luminous display LED modules 30 are joined in a matrix on the same plane, and the black encapsulant sheet 1 is applied to the joined LED modules in the same manner as described above. By stacking, an LED module for a large-sized self-luminous display body, and furthermore, a large-sized micro LED display device can be constructed. In this case, the excellent uniformity of the film thickness of the black encapsulant sheet 1 after hot-pressing maintains the uniformity of the display surface at the junction between the individual LED modules to be joined. It can also contribute to improving the image quality of the micro LED display device.

(Manufacturing method of micro LED display device)
The micro LED display device 100 (100B) is a laminate obtained by laminating an LED module 30 for a self-luminous type display body in which an LED element 10 is mounted on a wiring board 20, a black sealing material sheet 1, and a transparent optical layer 2. It can be produced by forming a body 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. For example, it is preferable to manufacture the micro LED display device 100 by bonding the transparent optical layer 2 to the black sealing material sheet 1 via the adhesive layer 3 .

(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, is configured by mounting an LED element 10 on a wiring substrate 20 having a wiring portion 22 formed on a support substrate 21. be.

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 As the support substrate 21, a conventionally known glass epoxy hard substrate can be used as an electronic circuit substrate.

Here, the glass-epoxy-based hard substrate usually has a brownish color on its surface. Conventionally, in the micro LED display device, the display quality deteriorates due to the light reflected by the brown-colored surface of the support substrate disposed inside and transmitted to the outside of the display surface side. sometimes caused a decline. In order to prevent such a problem, in the conventionally configured micro LED display device 100C (see FIG. 5), the light shielding layer 4 as shown in the figure is provided on the transparent sealing material sheet 1D through which almost all visible light is transmitted. was laminated separately to the On the other hand, in the micro LED display device 100 (100B) (see FIG. 2) of the present invention, the visible light transmittance is 5% to 70% as a sealing material that also functions as the light shielding layer 4 in the conventional configuration. A black encapsulant sheet 1 having the following is arranged. Therefore, the present invention exerts a particularly advantageous effect in a micro LED display device using a glass-epoxy-based hard substrate having a colored surface other than white and black, representing a brown color, as the support substrate 21 .

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 a large micro LED display device. be able to. 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 having any structure can be used in the LED display device 100 (100B) of the present invention, an LED element such as the one disclosed in JP-A-2006-339551 as a "chip-shaped electronic component" can be used. Micro-sized LED elements can be particularly preferably used. 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 black encapsulant sheet 1 is preferable as an encapsulant to be mounted on the micro LED display device 100 (100B) in that it is made of an olefin-based resin that is excellent in 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.

(Black encapsulant sheet)
In the micro LED display device 100 (100B) according to the present invention, the black sealing material sheet 1 laminated on the LED module 30 is formed by forming a film of a sealing material composition using an olefin resin such as polyethylene as a base resin. , a sheet-shaped member having a “black” color.

Here, the term “black” in this specification means that the CIE color coordinates are −1.0≦a ^* ≦2.5 and −1 with a C light source and a viewing angle of 2 deg, measured in accordance with JISZ8701-1999. 0≦b ^* ≦15.0, and for the L ^* value, it means a tint in the range of 0≦L ^* ≦50.

The black encapsulant sheet 1 may be a single-layer film, but as shown in FIG. A film is preferred. 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. To tell. When the black encapsulant sheet 1 has a three-layer structure consisting of a skin layer, a core layer, and a skin layer, a black pigment is added only to the core layer 1A, and the skin layers 1B and 1C exposed on both outermost surfaces have this is not added and the transparent layer is left as it is. As a result, it is possible to avoid contamination of the rubber roll, emboss roll, cooling roll, guide roll, etc. of the film forming apparatus with the black pigment.

The thickness of the black sealing material sheet 1 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 to achieve good lamination without gaps. can.

The black colorant used to impart an appropriate color to the black encapsulant sheet 1 is preferably a pigment-based material. For example, carbon black, which is commonly used as a black pigment, can be mentioned as a preferred pigment. In the case of coloring for display applications, a plurality of dyes are often combined to develop a black color. In addition, as a durability test of the display, a durability test under an environment of 85° C. 85% or 60° C. 90% is required, but in the case of the dye system, the dye deterioration (discoloration deterioration) is likely to occur, so it is better to use the pigment system. is preferred. However, if it is necessary to lower the transmittance of a specific wavelength in order to widen the color tone range, it is also possible to apply a dye.

When carbon black is used as the black pigment used in the black encapsulant sheet 1, the content of carbon black in the resin component of the black encapsulant sheet is 0.0001% by mass or more and 0.08% by mass or less. preferable. In order to express the necessary blackness when the carbon black content is less than 0.0001% by mass, the thickness of the encapsulant sheet must be set to a thickness greater than that necessary to maintain the original sealing function. It becomes necessary to do. On the other hand, if the content exceeds 0.08% by mass, the light from the LED cannot be properly transmitted, making it difficult to obtain a desirable image. By setting the content of carbon black within the above range, it is possible to achieve stable coloring with sufficiently few spots.

Further, it is more preferable to add a dispersant to the black encapsulant sheet 1 . Various metal soaps can be used as the dispersant. As the dispersing agent, it is also possible to use a low content polyethylene wax or the like in addition to the metallic soap. Specific examples of preferred dispersants include lithium stearate, magnesium stearate, calcium stearate, barium stearate zinc stearate, calcium laurate, barium laurate, zinc laurate, calcium ricinoleate, barium ricinoleate, zinc ricinoleate, Zinc octylate and the like can be mentioned. Among them, calcium stearate, zinc stearate, zinc laurate, etc. are preferable from the viewpoint of the melting point of the resin. In particular, if calcium stearate, which is often contained in ordinary polyethylene resins, is used as a dispersant, the compatibility may deteriorate. can be used preferably.

Here, when forming a sheet with a concealing property, there is usually little need to consider streaks such as die lines during film formation, but the visible light transmittance is 5% like the black encapsulant sheet 1. When forming a sheet having the above transparency, it is essential to increase the dispersibility of the pigment. If the amount added is small, the effect of dispersing is weakened, and if the amount added is large, it causes slippage during film formation. It is preferable that it is more than mass % and less than 0.002 mass %. When the content of the dispersant is less than 0.00002% by mass, the dispersibility of the pigment is reduced, resulting in uneven coloring density, for example, striped patterns on the surface, etc., for self-luminous display applications. If the content exceeds 0.002% by mass, a constant film thickness cannot be maintained due to screw slippage during film formation. increased risk of difficulty. On the other hand, by adding a dispersant within the above range, it is possible to sufficiently improve the dispersibility of the pigment while preventing slippage of the screw during film formation.

In addition, in the black encapsulant sheet 1, a combination with an antioxidant is also important in order to promote good dispersion of the pigment. It is preferable to add it to the resin component at a ratio of about 200 to 800 ppm.

In the self-luminous display body of the present invention, the "melt viscosity (η*1) at a shear rate of 2.43 × 10 sec ^-1 measured at a temperature of 120 ° C." of the black sealing material sheet 1 is 1 It is preferably 0×10 ³ poise or more and 1.0×10 ⁵ poise or less, and more preferably 5.0×10 ³ poise or more and 1.0×10 ⁵ poise or less. In addition, the above-mentioned melt viscosity in this specification shall mean the melt viscosity measured by the method based on JISK7199.

By setting the above-mentioned "melt viscosity" to 1.0×10 ³ poise or more, the extrusion of the resin due to excessive flow during the hot press processing of the encapsulant sheet and the stress from the side to the LED element In addition, the uniformity of the film thickness of the encapsulant sheet after the hot press process can be maintained satisfactorily. 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 if the thickness of the central portion of the black encapsulant sheet 1 and the thickness of the edge portions differ even slightly, the encapsulant sheet becomes lens-shaped, which is intended for the display quality of the micro LED display device. This is because it will give an unfavorable effect.

On the other hand, by setting the above-mentioned "melt viscosity" to 1.0×10 ⁵ poise or less, it is possible to maintain good moldability during hot press processing of the encapsulant sheet.

Here, conventionally, the value of MFR, which is widely used as an indicator of the fluidity of sealing material sheets, is measured at 190° C. when measured according to JIS K6922. It deviates from the temperature at which the sealing material sheet for the self-luminous display body melts during the heat press processing. As will be shown later in Examples, even if the MFR value is in a suitable value range, if the above-mentioned "melt viscosity" exceeds a predetermined value, the necessary moldability may not be ensured. As an index for controlling the fluidity of the resin during hot press processing, instead of the MFR, the shear modulus at a temperature of 120° C., that is, the shear rate measured at a temperature of 120° C.2. By using the melt viscosity (η*1) at 43×10 sec-1 as an index for optimizing the physical properties of the base resin, it is possible to develop a highly effective and precise resin that is more in line with the actual use of the encapsulant sheet. A selection index can be obtained.

In the self-luminous display of the present invention, the Vicat softening point of the black encapsulant sheet 1 is preferably higher than 60° C. and 100° C. or lower, more preferably 70° C. or higher and 90° C. or lower. preferable. By setting the Vicat softening point of the black sealing material sheet 1 to more than 60° C., the occurrence of blocking in the manufacturing process of the self-luminous display body using the sealing material sheet can be suppressed more reliably, and the self-luminous display can be obtained. It can contribute to the improvement of body productivity. On the other hand, by setting the temperature range to 100° C. or less, it is possible to sufficiently 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. 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 100°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.

From another point of view, in the self-luminous display of the present invention, the durometer A hardness of the black encapsulant sheet 1 is preferably 60 or more and less than 95. If the durometer A hardness of the encapsulant sheet is less than 60, the crystallization speed of the olefin resin will be slow, and the sheet extruded from the extruder will be sticky, making it difficult to peel off with a cooling roll, resulting in encapsulation. It becomes difficult to obtain a sheet of material. In addition, since the sealing material sheet becomes sticky, blocking occurs, and the feeding of the sheet becomes difficult. On the other hand, when the durometer A hardness exceeds 95, the moldability is deteriorated, and the conformability to the unevenness of the LED element becomes insufficient.

In the self-luminous display body of the present invention, the melt mass flow rate (MFR) at 190° C. of the resin sheet constituting the black sealing material sheet 1 is 0.1 g/10 min or more and less than 12.0 g/10 min. It is preferably 0.1 g/10 min or more and less than 5.0 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 black encapsulant sheet 1, a wide range of olefinic thermoplastic resins can be selected. 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.

As the olefin-based resin used as the base resin of the encapsulant composition forming the black encapsulant sheet 1, a polyethylene-based resin having a density of 0.870 g/cm ³ or more and 0.910 g/cm ³ or less is preferably used. can be done. 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.

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. Since such a graft copolymer has a high degree of freedom of silanol groups that contribute to adhesive strength, adhesion of the black sealing material sheet 1 to other members in a self-luminous display such as the micro LED display device 100 can improve sexuality. The content of the silane-modified polyethylene resin in the encapsulant composition is, for example, in the case of a multilayer encapsulant sheet having a structure of skin layer-core layer-skin layer, the encapsulant for the core layer In the material composition, it is preferably 2% by mass or more and 20% by mass or less, and in the sealing material composition for the skin layer, 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.

By using a silane-modified polyethylene resin as a component of a sealing material composition for a self-luminous display, excellent strength, durability, etc., weather resistance, heat resistance, water resistance, light resistance, and wind pressure resistance can be obtained. , hail resistance, and other characteristics, and have extremely excellent heat-sealability without being affected by manufacturing conditions such as thermocompression bonding for manufacturing self-luminous display bodies. A self-luminous display suitable for various uses can be manufactured at a low cost.

The black encapsulant sheet 1 is preferably a thermoplastic encapsulant that does not require cross-linking treatment after film formation. A "weakly cross-linked sealing material" obtained by weakly cross-linking a polyethylene-based sealing material composition can also be used as such a "cross-linking-free" sealing material sheet. "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.

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>
First layer (skin layer): φ30 mm extruder, second layer (core layer): φ30 mm extruder, third layer (skin layer): φ30 mm extruder, layer ratio 1: Using a film forming machine having a T-die with a width of 300 mm, extruding three layers of molten resin of skin layer-core layer-skin layer in a ratio of 3:1 at a temperature of 210° C. and a take-up speed of 1.1 m/min. , and formed into a sheet with a thickness of 150 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.
As a sealing material composition for the first layer (skin layer), the following "base resin 1" is added to 100 parts by mass, and the following "additive resin 1 (weather resistant agent masterbatch)" is added to 5 parts by mass. Addition resin 2 (silane-modified polyethylene resin)” was mixed at a rate of 20 parts by mass.
As a sealing material composition for the second layer (core layer), the following "base resin 1" is added to 100 parts by mass, and the following "additive resin 1 (weather resistant agent masterbatch)" is added to 5 parts by mass. 1 part by mass of "additive resin 2 (silane-modified polyethylene resin)" and 0.1 part by mass of "additive resin 3 (black masterbatch)" were mixed.
As a sealing material composition for the third layer (skin layer), the following "base resin 1" is added to 100 parts by mass, and the following "additive resin 1 (weather resistant agent masterbatch)" is added to 5 parts by mass. Addition resin 2 (silane-modified polyethylene resin)” was mixed at a rate of 20 parts by mass.
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 with 0.15 parts by mass of dicumyl peroxide as a catalyst) and 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.
Additive resin 3: (black masterbatch)
40 parts by mass of carbon black with a density of 0.91 g/cm3 and an MFR of 5.0 g/10 min, 2 parts by mass of metal soap (calcium stearate), and a linear low-density polyethylene (LLDPE) with a density of 0.910 g/cm3 ) black masterbatch with 60 parts by weight.

<Evaluation Example 1: Film thickness uniformity>
A 50 μm untreated ETFE was laminated as a release film on the front and back of the sealing material sheet of the example cut to 30 × 30 cm, and then a glass of 30 × 30 cm and a thickness of 3 mm was laminated on the front and back. This laminate was subjected to vacuum lamination using a vacuum laminator for manufacturing solar cell modules under 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. After cooling, the glass and ETFE were peeled off to obtain a "sealing material sample." With respect to the thickness of this "sealing material sample", the film thickness was measured at two points, the central portion and the point 2 cm from the corner toward the center, using a digital film thickness meter. The test was performed 3 times. According to the findings of the inventors of the present application, in order for the black encapsulant sheet to exhibit its function as a light shielding layer in a micro LED, the film thickness difference between the two locations is at most within 10%. is essential. As a result of the above test, the film thickness difference between the central portion and the portion 2 cm from the corner was within 10 μm (7%) at maximum.

<Evaluation Example 2: Uniformity of Visible Light Transmittance>
Regarding the "sealing material sample" for which the film thickness uniformity was measured in <Evaluation Example 1> above, visible light with a wavelength of 380 nm to 780 nm at the center part and the point 2 cm from the corner toward the center. was calculated as an average of spectral transmittances measured by V-670 manufactured by JASCO Corporation. The test was performed 3 times. According to the findings of the inventors of the present application, in order for the black encapsulant sheet to exhibit its function as a light shielding layer in a micro LED, the difference in the transmittance of visible light at the two locations must be at most 2. must be within %. As a result, the difference in visible light transmittance between the central portion and the portion 2 cm from the corner was within 1.2% at maximum.

The results of Evaluation Example 1 and Evaluation Example 2 show that the self-luminous display body 100 (100B) of the present invention, which has the layer structure shown in FIG. This proves that it has optical characteristics equivalent to those of the light-emitting display body 100C.

As described above, the self-luminous display of the present invention has a simplified layer structure while maintaining the image display quality of a conventional self-luminous display including a light shielding layer. It is clear that it can contribute to the improvement of productivity.

REFERENCE SIGNS LIST 1 black encapsulant sheet 2 transparent optical layer 3, 3A, 3B adhesive layer 4 light shielding layer 10 LED element (light emitting element)
REFERENCE SIGNS LIST 11 LED light-emitting chip 12 resin cover 20 wiring substrate 21 support substrate 22 wiring part 23 solder layer 30 LED module (light-emitting module)
100, 100A, 100B, 100C Micro LED display device (self-luminous display)

Claims (12)

a light-emitting module in which a plurality of light-emitting elements are mounted on a wiring substrate;
a black encapsulant sheet having an olefin resin as a base resin;
a transparent optical layer;
The black sealing material sheet covers the surfaces of the light emitting element and the wiring board and is laminated on the light emitting module,
The self-luminous display body, wherein the transparent optical layer is laminated on the black sealing material sheet. The black encapsulant sheet has a film thickness difference of 10 μm or less as measured by the following film thickness uniformity test.
The sealing material sheet according to claim 1.
(Film thickness uniformity test)
A 50 μm untreated ETFE film is laminated as a release film on the front and back of a sealing material sheet cut to 30×30 cm. The body is subjected to vacuum lamination using a vacuum laminator for solar cell module production under 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. After cooling, the glass and ETFE are peeled off to obtain a "sealant sample." With respect to the thickness of this "sealing material sample", the film thickness is measured at two points, the central portion and the point 2 cm from the corner toward the center, with a digital film thickness meter. The black encapsulant sheet contains a phenol-based antioxidant or a phosphorus-based antioxidant, and the content of the antioxidant in the resin component of the black encapsulant sheet is 200 ppm or more. 800 ppm or less,
The encapsulant sheet according to claim 1 or 2. The black encapsulant sheet contains carbon black, and the content of the carbon black in the resin component of the black encapsulant sheet is 0.0001% by mass or more and 0.08% by mass or less. 4. The self-luminous display according to any one of claims 1 to 3. The black encapsulant sheet contains a dispersant made of one or more kinds of metal soaps, and the content of the dispersant in the resin component of the black encapsulant sheet is 0.00002% by mass. 5. The self-luminous display according to any one of claims 1 to 4, wherein the content is 0.002% by mass or less. The black encapsulant sheet has a melt viscosity (η*1) of 1.0×10 ³ poise at a shear rate of 2.43×10 sec ⁻¹ measured at a temperature of 120° C. by a method conforming to JIS K7199. 6. The self-luminous display according to claim 1, wherein the poise is 1.0×10 ⁵ poise or less. The self-luminous display according to any one of claims 1 to 6, wherein said black encapsulant sheet has a Vicat softening point exceeding 60°C and not higher than 100°C. The black encapsulant sheet is a multilayer film having a three-layer structure consisting of a skin layer, a core layer, and a skin layer, wherein only the core layer contains a black pigment, and both skin layers contain a black pigment. The self-luminous display according to any one of claims 1 to 7, which does not contain 9. The wiring board according to any one of claims 1 to 8, wherein the supporting substrate of the wiring substrate is a glass epoxy hard substrate, and the color of the surface of the supporting substrate on the LED element mounting surface side is colored other than white and black. A self-luminous display body. 10. The self-luminous display according to any one of claims 1 to 9, 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,
11. The self-luminous display according to claim 10, 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,
12. The self-luminous display according to claim 11, wherein the LED elements are arranged at intervals of 0.05 mm or more and 5 mm or less.

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