WO2023063285A1

WO2023063285A1 - Surface emission device, display device, method for manufacturing surface emission device, and sealing member sheet for surface emission device

Info

Publication number: WO2023063285A1
Application number: PCT/JP2022/037769
Authority: WO
Inventors: 喜洋金井; 淳朗續木; 麻理衣西川; 康佑佐伯; 絵梨奈大橋
Original assignee: 大日本印刷株式会社
Priority date: 2021-10-11
Filing date: 2022-10-11
Publication date: 2023-04-20
Also published as: TW202329501A; JP2024016138A; JPWO2023063285A1; JP2024020269A

Abstract

The present disclosure provides a sealing member sheet for a surface emission device, the sealing member sheet having a sealing member (5) that seals a light-emitting diode element (3), and a warpage prevention layer (7) that is located on the sealing member (5) and has a linear expansion coefficient within the range from -15×10^-6/°C to 10×10^-6/°C.

Description

Surface emitting device, display device, manufacturing method of surface emitting device, and sealing member sheet for surface emitting device

The present disclosure relates to a surface light-emitting device, a display device using the same, a method for manufacturing the surface light-emitting device, and a sealing member sheet for a surface light-emitting device.

In recent years, there has been a demand for higher image quality display in the field of display devices. 2. Description of the Related Art A display device using a light-emitting diode element is attracting attention and is being developed because of its advantages of high brightness and high contrast. In the following description, "light emitting diode" may be referred to as "LED". For example, backlights using LED elements are being developed as backlights used in liquid crystal display devices. The backlight is also called a mini-LED backlight.

Here, LED backlights are broadly classified into a direct type and an edge light type. Edge-light type LED backlights are usually used in small and medium-sized display devices such as mobile terminals such as smartphones, but direct type LED backlights are often used from the viewpoint of brightness. being considered. On the other hand, in large-sized display devices such as large-screen liquid crystal televisions, in many cases, a direct type LED backlight is used.

A direct type LED backlight has a structure in which a plurality of LED elements are arranged on a substrate. In such a direct type LED backlight, by independently controlling a plurality of LED elements, the brightness of each area of the LED backlight is adjusted according to the brightness of the displayed image, so-called local dimming is realized. be able to. As a result, it is possible to significantly improve the contrast and reduce the power consumption of the display device.

International Publication 2013/018902

In a surface emitting device such as a direct type LED backlight, a diffuser plate or a transmissive reflector plate (hereinafter referred to as a diffuser member) is placed above the LED elements from the viewpoint of suppressing luminance unevenness. In order to suppress luminance unevenness, it is necessary to separate the LED element and the diffusion member. Therefore, conventionally, pins and spacers are arranged to maintain a predetermined gap between the LED element and the diffusion member (for example, Patent Document 1). FIG. 12(a) shows a conventional LED backlight 60 in which pins 65 are arranged in order to secure the distance d between the LED elements 63 on the support substrate 62 and the diffusion member 66. FIG. 12(b1) shows a conventional LED backlight 61 in which spacers 67 are arranged between a support substrate 62 and a diffusion member 66, and FIG. 12(b2) is a schematic plan view of the spacers 67. FIG.

When the pins and spacers are arranged in this manner, the light emitted from the LED element may be blocked or reflected by the pins or spacers, resulting in uneven brightness. Therefore, in Patent Document 1, for example, it is necessary to further dispose a diffuser plate or the like above the transmissive reflector plate, which makes it difficult to reduce the thickness of the module. As described above, the conventional surface emitting device has a problem that it is difficult to realize uniformity of luminance in the plane and reduction in thickness at the same time.

In order to solve such problems, it is conceivable to dispose a sealing member having light diffusing properties between the LED support substrate that supports the LEDs and the diffusion member. As a result, it is possible to improve the in-plane uniformity of luminance and reduce the thickness of the device, which may solve the above-described problems. However, in the surface emitting device including the LED supporting substrate and the sealing member, there is a possibility that a problem may occur such as warping during manufacturing.

The present disclosure has been made in view of the above problems, and is mainly to provide a surface light emitting device that can prevent warping during manufacturing and improve the yield during manufacturing of the surface light emitting device. aim.

In order ^to achieve the above object, the present disclosure provides a sealing member that seals a light emitting diode element; and an anti-warp layer whose temperature is within the range of ⁻⁶ /° C. or less.

The present disclosure also provides a surface used for a surface light emitting device, in which a sealing member for sealing a light emitting diode element and an anti-foaming layer disposed on one side of the sealing member are laminated. Provided is a surface light-emitting device sealing member sheet, wherein the elastic modulus of the material constituting the anti-foaming layer is 500 MPa or more.

The present disclosure is a surface light emitting device for use in a surface light emitting device, which is formed by laminating a sealing member for sealing a light emitting diode element and an anti-foaming layer disposed on one side of the sealing member. Provided is a sealing member sheet for a surface emitting device, wherein the melting point of the material constituting the anti-foaming layer is 140° C. or higher.

The present disclosure also provides a light emitting diode substrate having a supporting substrate and a light emitting diode element disposed on one side of the supporting substrate, and a light emitting diode substrate disposed on a surface of the light emitting diode substrate facing the light emitting diode element, a sealing member that seals an element; a warp prevention layer disposed on a surface of the sealing member opposite to the light emitting diode substrate; and a diffusion member disposed, wherein the sealing member has a haze value of 4% or more, a thickness greater than that of the light emitting diode element, and a material constituting the anti-warpage layer. linear expansion coefficient is in the range of −15×10 ⁻⁶ /° C. or more and 10×10 ⁻⁶ /° C. or less.

The present disclosure further provides a light-emitting diode substrate having a support substrate and a light-emitting diode element arranged on one surface side of the support substrate; a sealing member that seals the element; a diffusion member that is disposed on the surface of the sealing member opposite to the light emitting diode substrate; and a diffusion member that is disposed on the surface of the light emitting diode substrate opposite to the light emitting diode element. and a warp prevention layer, wherein the sealing member has a haze value of 4% or more, a thickness greater than that of the light emitting diode element, and is made of a material that constitutes the warp prevention layer. Provided is a surface light-emitting device having a coefficient of linear expansion equal to or greater than the coefficient of linear expansion of the material forming the sealing member.

The present disclosure provides a display device comprising a display panel and the above-described surface emitting device arranged on the back surface of the display panel.

The present disclosure is a method for manufacturing the above-described surface light-emitting device, wherein the warp prevention layer, the sealing member, and the light-emitting diode substrate arranged so that the light-emitting diode element is on the side of the sealing member are arranged in this order. Provided is a method for manufacturing a surface emitting device, comprising the steps of preparing a stacked layered body and thermocompression bonding the layered body.

The present disclosure is a method for manufacturing the above-described surface emitting device, comprising a step of thermocompression bonding a first laminate in which the warp prevention layer and the sealing member are laminated, and the thermocompression bonded first laminate and thermocompression bonding a second laminate having the light-emitting diode substrate arranged so that the light-emitting diode element is on the sealing member side, on the sealing member side surface of the surface light-emitting device. A manufacturing method is provided.

The present disclosure has the effect of being able to provide a surface light-emitting device capable of preventing warping during manufacturing and improving the yield of manufacturing the surface light-emitting device.

1 is a schematic cross-sectional view illustrating a surface emitting device according to the present disclosure; FIG. FIG. 4 is a process diagram showing an example of a method of forming a sealing member according to the present disclosure; FIG. 2 is a schematic cross-sectional view illustrating the structure of the sealing member of the surface emitting device according to the present disclosure; FIG. 4 is a schematic cross-sectional view showing an example of a second diffusion member; FIG. 4 is a schematic cross-sectional view showing an example of a surface emitting device including a second diffusion member in the present disclosure; 5 is a graph illustrating transmitted light intensity distribution; FIG. 4A is a schematic plan view and a cross-sectional view showing an example of a first embodiment of a reflective structure of a second diffusion member; FIG. 9A is a schematic plan view and a cross-sectional view showing an example of a second embodiment of the reflecting structure of the second diffusion member; FIG. 11 is a schematic cross-sectional view showing another example of the second aspect of the reflective structure of the second diffusion member; FIG. 4 is a schematic cross-sectional view showing another example of a surface emitting device according to the present disclosure; 1 is a schematic diagram showing an example of a display device of the present disclosure; FIG. 1 is a schematic cross-sectional view of a conventional LED backlight; FIG.

Embodiments of the present disclosure will be described below with reference to the drawings and the like. However, the present disclosure can be embodied in many different forms and should not be construed as limited to the description of the embodiments exemplified below. In addition, in order to make the description clearer, the drawings may schematically show the width, thickness, shape, etc. of each member compared to the embodiment, but this is only an example, and the interpretation of the present disclosure is not limited to In addition, in this specification and each figure, the same reference numerals may be given to the same elements as those described above with respect to the existing figures, and detailed description thereof may be omitted as appropriate.

In this specification, when expressing a mode of arranging another member on top of a certain member, unless otherwise specified, when simply describing “on the surface side”, it means directly above or directly below so as to contact a certain member. It includes both the case of arranging another member on the side and the case of arranging another member above or below a certain member via another member.

Also, in this specification, terms such as "sheet", "film", and "plate" are not to be distinguished from each other based only on the difference in designation. For example, the term "sheet" is used in the sense of including members called films and plates.

As described above, in the newly proposed surface emitting device including the LED support substrate and the sealing member, there is a problem that warpage may occur during manufacturing.

As a result of intensive studies by the present inventors in order to solve the above-mentioned new problem, the reason why the warp occurs is that after the LED support substrate and the sealing member are thermally compressed during manufacturing, the linear expansion coefficients of both are different. I found out that this is the cause. Thus, the problem is solved by arranging the anti-warp layer having a coefficient of linear expansion in a predetermined relationship with respect to the sealing member at an appropriate position with respect to the sealing member.

A. Surface Emitting Device The surface emitting device in the present disclosure can be divided into three aspects. Hereinafter, each embodiment will be described separately.

I. First Embodiment Hereinafter, a surface emitting device of this embodiment will be described with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing an example of the surface emitting device of this embodiment. As illustrated in FIG. 1, a surface light emitting device 1 includes a support substrate 2, an LED substrate 4 having LED elements 3 arranged on one side of the support substrate 2, and an LED substrate 4 on the LED element 3 side. A sealing member 5 arranged on the surface side to seal the LED element 3, a diffusion member 6 arranged on the surface side of the sealing member 5 opposite to the LED substrate 4 side, the sealing member 5 and the and an anti-warp layer 7 disposed between the diffusion member 6 . The sealing member 5 in this embodiment has a haze value of 4% or more, a thickness d greater than the thickness of the LED element 3, and a linear expansion coefficient of the material constituting the warp prevention layer 7 is - It is characterized by being in the range of 15×10 ⁻⁶ /° C. or more and 10×10 ⁻⁶ /° C. or less.

In general, in a surface emitting device, for example, when a means such as thermocompression bonding is used to join the sealing member and the LED substrate, a line between the LED substrate and the sealing member is formed during subsequent cooling. Warpage may occur due to differences in expansion coefficients.
Further, when the surface emitting device is used at extremely high or low temperatures, warping may occur due to the difference in coefficient of linear expansion between the LED substrate and the sealing member.

This embodiment has been made in order to solve such problems, and the anti-warp layer is arranged between the sealing member and the diffusion member, and a wire of a material constituting the anti-warp layer is disposed between the sealing member and the diffusion member. Since the coefficient of expansion is in the range of -15×10 ^-6 /°C or more and 10×10 ^-6 /°C or less, the problem of warpage described above is solved.

In addition, in the conventional surface light-emitting device, for example, when the surface light-emitting device is used at extremely high temperatures for a long time, there is a problem that air bubbles are generated between the LED substrate and the sealing member. This is caused by the gas generated from the LED substrate by heating, or when a reflective layer or the like is provided on the LED substrate, air existing between the LED substrate and the reflective layer or the like due to air entrainment or the like may cause the interface It occurs due to causes such as oozing along.

In the LED element sealed with the sealing member, the light emitting surface of the sealing member and the LED element are directly bonded, and the refractive index difference at the interface becomes small, so the light extraction efficiency is higher than that of the unsealed LED element. improves. However, if such bubbles exist, the light extraction efficiency cannot be improved as described above, resulting in a problem of lowering the luminous efficiency of the surface light emitting device.
In this embodiment, by providing the anti-warpage layer, the above problem is also solved.
Each structure of the surface emitting device of this embodiment will be described below.

1. Sealing Member The sealing member in this embodiment has a haze value of 4% or more and is thicker than the LED element. The sealing member has optical transparency and is arranged on the light emitting surface side of the LED substrate.

(1) Haze Value The haze value of the sealing member in this embodiment is 4% or more, preferably 8% or more, and more preferably 10% or more. If it is smaller than the above value, luminance unevenness cannot be suppressed. On the other hand, the upper limit is not particularly limited, but is, for example, 85% or less, preferably 60% or less, more preferably 30% or less. In this specification, the haze value is a value for the entire sealing member, cut out from the surface emitting device, and measured using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory) to JIS K7136:2000. It can be measured by a method according to

The method for adjusting the haze value for obtaining the haze value described above is not particularly limited, but includes a method using the degree of crystallinity of the resin, a method of changing the content of fine particles in the resin, and the like. Among them, the method of adjusting the crystallinity of the resin is preferable. This is because when the haze value is increased by increasing the crystallinity of the resin, it is possible to obtain the effect of reducing the rectilinear transmitted light.

(2) Thickness The thickness of the sealing member in the present embodiment may be any thickness as long as it is thicker than the LED element, specifically preferably 50 μm or more, more preferably 80 μm or more, and particularly preferably 200 μm or more.
On the other hand, the thickness of the LED element is preferably 800 μm or less, more preferably 750 μm or less, and particularly preferably 700 μm or less.

The "thickness" in this specification is measured using a contact-type film thickness measuring device (Mitutoyo Thickness Gauge 547-301). The same is true for size measurements such as "size".

If the thickness is smaller than the above thickness, the thickness becomes insufficient and the light emitted from the LED element cannot be diffused over the entire light emitting surface, and the brightness cannot be improved uniformly within the surface. Moreover, when it is larger than the said thickness, thickness reduction cannot be achieved.

(3) Material of Sealing Member The material contained in the sealing member in the present embodiment is not particularly limited as long as it is a material having the haze value described above, but a thermoplastic resin or the like is preferable. By using a thermoplastic resin, it is possible to adjust the haze value to be higher than in the case of using a thermosetting resin, and to form the sealing member at a low temperature.

When the sealing member contains a thermoplastic resin, a sheet-like sealing member (hereinafter sometimes referred to as a sealing member sheet) made of a sealing material composition containing the thermoplastic resin. ) can be used. FIG. 2 is a process drawing showing an example of a method of forming a sealing member in this embodiment. For example, as shown in FIG. 2(a), an LED substrate 4 and a sealing member sheet 5a having a warp prevention layer 7 disposed on one surface are prepared, and on the surface of the LED substrate 4 on the LED element 3 side, The surface of the sealing member sheet 5a opposite to the anti-warp member 7 is laminated. Next, by press-bonding these by using, for example, a vacuum lamination method, as shown in FIG. can form objects.

On the other hand, when the sealing member contains a curable resin such as a thermosetting resin or a photocurable resin, a liquid sealing material is usually used. When a liquid sealing material is used, a phenomenon may occur in which the thickness of the end portion becomes thicker or thinner than that of the central portion due to surface tension or the like. Moreover, in the case of a curable resin, volume shrinkage or the like tends to occur during curing, and as a result, the thickness of the central portion and the end portions of the sealing member after curing may become uneven. When the thickness of the sealing member is uneven in this manner, luminance unevenness may occur.

On the other hand, when a sheet-like sealing material is used, the thickness distribution of the coating film occurs due to surface tension and the thickness distribution due to heat shrinkage or light shrinkage, which occurs when a liquid sealing material is used. It is possible to avoid the occurrence of unevenness on the surface of the sealing member, such as occurrence of unevenness. Therefore, a sealing member with good flatness can be obtained, and a higher quality display device can be provided.

(a) Thermoplastic resin In the present embodiment, olefin resin, ethylene-vinyl acetate copolymer (EVA), polyvinyl butyral resin and the like can be used as the thermoplastic resin.

Among them, the thermoplastic resin is preferably an olefin resin. This is because the olefin-based resin is particularly resistant to producing components that degrade the LED substrate and has a low melt viscosity, so that the above-described LED element can be well sealed. Among olefin resins, polyethylene resins, polypropylene resins, and ionomer resins are preferable.

Here, the polyethylene-based resin in the present specification includes not only ordinary polyethylene obtained by polymerizing ethylene, but also a compound having an ethylenically unsaturated bond such as α-olefin obtained by polymerizing Resins, resins obtained by copolymerizing a plurality of different compounds having ethylenically unsaturated bonds, modified resins obtained by grafting other chemical species onto these resins, and the like are included.

In particular, from the viewpoint of obtaining the haze value, it is preferable that the sealing member in this embodiment uses a polyethylene-based resin having a density of 0.870 g/cm ³ or more and 0.930 g/cm ³ or less as a base resin. In particular, it is preferable to use a polyethylene-based resin having a density of 0.890 g/cm ³ or more and 0.930 g/cm ³ or less as the base resin. When the sealing member is a multi-layer member as will be described later, it is preferable to use a polyethylene-based resin having the density described above as the base resin of the core layer. The density is measured according to JIS Z 8807:2012.
Here, in the present disclosure, the “base resin” refers to a resin having the largest content mass ratio among the resin components of the resin composition containing the base resin. .

A silane copolymer (hereinafter also referred to as "silane copolymer") obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as comonomers can be preferably used. By using such a resin, higher adhesion between the LED substrate and the sealing member can be obtained. The silane copolymer described in JP-A-2018-50027 can be used.

(b) Melting Point The melting point of the thermoplastic resin used in this embodiment is not particularly limited as long as the LED element can be sealed, but for example, it is preferably 90° C. or higher and 135° C. or lower. Among them, it is preferable that the thermoplastic resin is not softened by heat generation during LED light emission, and it is preferable to use a thermoplastic resin having a temperature of 90° C. or more and 120° C. or less.

The melting point of the thermoplastic resin can be measured, for example, by differential scanning calorimetry (DSC) in accordance with the method for measuring the transition temperature of plastics (JISK7121:2012).
This is the highest melting point when multiple thermoplastic resins are included. When the sealing member is a multilayer member as described later, it is preferable to use a thermoplastic resin having the above melting point as the base resin of the core layer.

(c) melt mass flow rate (MFR)
In addition, the thermoplastic resin in this embodiment has a melt viscosity that can follow the unevenness of the LED element and other members arranged on one surface side of the LED substrate and can enter the gap by heating. is preferably used.

Specifically, the melt mass flow rate (MFR) of the thermoplastic resin to be used is preferably 0.5 g/10 minutes or more and 40 g/10 minutes or less, and is 2.0 g/10 minutes or more and 40 g/10 minutes or less. more preferably 2.0 g/10 minutes or more and 20 g/10 minutes or less. When the MFR is within the above range, it becomes possible to enter gaps between LED elements, etc., and the sealing member can exhibit sufficient sealing performance and furthermore has excellent adhesion to the LED substrate. Because you can.

The MFR in this specification refers to the value at 190°C and a load of 2.16 kg measured according to JIS K7210-1:2014 A method. However, regarding the MFR of the polypropylene resin, it also refers to the MFR value at 230°C and a load of 2.16 kg according to the JIS K7210-1:2014 A method.

When the sealing member is a multilayer member as described later, the MFR is measured by the above-described measurement method while maintaining the multilayer state in which all the layers are integrally laminated, and the obtained measured value is used as the multilayer sealing member. shall be the MFR value of

d) Tensile modulus Further, the thermoplastic resin in this embodiment preferably has a tensile modulus at room temperature (25°C) of 20 MPa or more and 300 MPa or less, particularly preferably 20 MPa or more and 200 MPa or less. . The sealing member can exhibit sufficient adhesion to the LED substrate and has excellent impact resistance when, for example, the surface emitting device is subjected to an external impact. When the sealing member is a multi-layer member as described later, it is preferable to use a thermoplastic resin having the above elastic modulus as the base resin of the core layer. The value measured by JISK7127:1999 is used for the tensile modulus.

The modulus of elasticity is measured by the following tensile measurement.
・Measuring device: Universal material testing machine 5565 manufactured by Instron
・Load cell: 1kN
・Sample width: 10 mm
・Distance between chucks: 50mm
・Speed: 300mm/min

Additives such as antioxidants and light stabilizers may be added to the sealing member in addition to the thermoplastic resin.

e) Coefficient of linear expansion In this embodiment, the sealing member has a higher coefficient of linear expansion than the LED substrate described later. Therefore, as described above, after the sealing member and the LED substrate are thermally compressed in the manufacturing process, the shrinkage rate of the sealing member becomes larger than the shrinkage rate of the LED substrate, and as a result, the sealing member side is recessed. A problem arises that warping occurs.
The coefficient of linear expansion of the material constituting the sealing member used in this embodiment is preferably 20×10 ⁻⁶ /° C. or higher, particularly 150×10 ⁻⁶ /° C. or higher. is preferred. On the other hand, the upper limit is preferably 1500×10 ^-6 /°C or less, particularly preferably 1000×10 ^-6 /°C or less. Specifically, it is preferably in the range of 20 × 10 ^-6 /°C or more and 1500 × 10 ^-6 /°C or less, and particularly preferably 20 × 10 ^-6 /°C or more and 1000 × 10 ^-6 /°C or less, Above all, it is preferably in the range of 150×10 ^-6 /°C or more and 1000×10 ^-6 /°C or less. A value measured according to JISK7197:2012 is used as the coefficient of linear expansion.

(4) Structure of Sealing Member The sealing member in the surface emitting device in this embodiment may be a single layer member in which the sealing member 5 is composed of a single resin layer, as shown in FIG. Also, as shown in FIG. 3, the sealing member 5 includes a plurality of resin layers including a core layer 51 and a skin layer 52 disposed on at least one surface of the core layer 51 (FIG. 3(a)). ) and three layers in FIG. 3B) may be laminated. In particular, a two-layer structure having a core layer or the like and a skin layer disposed on the LED substrate side of the core layer is preferable. Note that FIG. 3 shows an example in which a reflective layer R is arranged around the LED element 3 .

When the sealing member in this embodiment is a multilayer member having a two-layer structure having a core layer and a skin layer disposed on the LED substrate side of the core layer, the film thickness ratio between the skin layer and the core layer (skin When skin layer:core layer is 1:X, the lower limit of X is preferably 0.1 or more, particularly preferably 0.5 or more. On the other hand, the lower limit is preferably 10 or less, particularly preferably 6 or less. That is, 1:0.1 to 1:10 is preferred, and 1:0.5 to 1:6 is particularly preferred.

Further, when the sealing member in this embodiment is a multi-layer member having a three-layer structure, the film thickness ratio between the skin layer and the core layer (skin layer:core layer:skin layer) is 1:Y:1. , Y is preferably 1 or more, particularly preferably 2 or more, while Y is preferably 10 or less, particularly preferably 8 or less. That is, the thickness ratio of the skin layer to the core layer (skin layer:core layer:skin layer) is preferably 1:1:1 to 1:10:1, particularly preferably 1:2:1 to 1:8. :1.

When the sealing member in this embodiment is a multilayer member, it is preferable that the core layer and the skin layer have the above thermoplastic resins with different density ranges, melting points, etc. as base resins. This is because it becomes easy to ensure adhesion to the LED substrate and molding properties with the skin layer while ensuring the haze value with the core layer.

In the case of the multi-layer member, it is possible to use a material with good adhesiveness, which is usually expensive, and molding properties that allow it to enter gaps between LED elements, etc., for the skin layer located on the LED substrate side of the multi-layer member. In the multilayer member, the material constituting the skin layer disposed on the LED substrate side is not particularly limited as long as it has high adhesion and high molding properties, but in the case of the above thermoplastic resin. It is preferable to use the above-mentioned silane copolymer or the like. Moreover, in the case of the thermoplastic resin, the material preferably contains the olefin resin and a silane coupling agent. Additives such as antioxidants and light stabilizers may be added to this layer.

(5) Preferred sealing member The sealing member in the present embodiment is preferably a multilayer member composed of a plurality of layers including a core layer and a skin layer arranged on at least one outermost surface, The core layer preferably uses a polyethylene resin with a density of 0.900 g/cm ³ or more and 0.930 g/cm ³ ^or less as a base resin. It is preferable to use a polyethylene-based resin having a density of ³ or less and a density lower than that of the base resin for the core layer as the base resin.

As the base resin for the core layer, a low density polyethylene resin (LDPE), a linear low density polyethylene resin (LLDPE), or a metallocene linear low density polyethylene resin (M-LLDPE) can be preferably used. . Among them, from the viewpoint of long-term reliability, a low-density polyethylene resin (LDPE) can be particularly preferably used as the base resin for the core layer.

The density of the polyethylene resin used as the base resin for the core layer is 0.900 g/cm ³ or more and 0.930 ^g /cm ³ or less, and more preferably 0.920 g/cm ³ or less. This is because, by setting the density of the base resin for the core layer within the above range, the haze value of the sealing member in this embodiment can be made equal to or higher than the above specific value. In addition, the sealing member can be provided with necessary and sufficient heat resistance without undergoing a cross-linking treatment.

The melting point of the polyethylene resin used as the base resin for the core layer is preferably 90°C or higher and 135°C or lower, more preferably 90°C or higher and 115°C or lower. By setting the melting point within the above range, the heat resistance and molding properties of the sealing member can be maintained within a preferable range. The melting point of the sealing member can be raised to about 165° C. by adding a high melting point resin such as polypropylene to the sealing material composition for the core layer. In this case, polypropylene is preferably contained in an amount of 5% by mass or more and 40% by mass or less with respect to the total resin components of the core layer.

The polypropylene contained in the core layer is preferably a homopolypropylene (homoPP) resin. Homo PP is a polymer consisting of polypropylene alone and has high crystallinity, so it has higher rigidity than block PP or random PP. By using this as an additive resin to the sealing material composition for the core layer, the dimensional stability of the sealing member can be enhanced. Further, the homo PP used as an additive resin to the sealing material composition for the core layer has an MFR of 5 g/10 minutes or more and 125 g/10 minutes or more at 230°C and a load of 2.16 kg, measured in accordance with JIS K7210:2014 A method. It is preferably 10 minutes or less. If the MFR is too small, the molecular weight will be too high and the rigidity will be too high, making it difficult to ensure the desirable and sufficient flexibility of the encapsulant composition. On the other hand, if the MFR is too large, the fluidity during heating cannot be sufficiently suppressed, and the sealing member sheet cannot be sufficiently endowed with heat resistance and dimensional stability.

The melt mass flow rate (MFR) of the polyethylene resin used as the base resin for the core layer is preferably 1.0 g/10 min or more and 7.5 g/10 min or less at 190° C. under a load of 2.16 kg. It is more preferably 1.5 g/10 minutes or more and 6.0 g/10 minutes or less. By setting the MFR of the base resin for the core layer within the above range, the heat resistance and molding properties of the sealing member can be maintained within preferable ranges. In addition, it is possible to contribute to the improvement of the productivity of the sealing member by sufficiently improving the processability at the time of film formation.

The content of the base resin with respect to the total resin components of the core layer is 70% by mass or more and 99% by mass or less, preferably 90% by mass or more and 99% by mass or less. As long as it contains the base resin within the above range, it may contain other resins.

As the base resin for the skin layer of the sealing member, similar to the sealing material composition for the core layer, low density polyethylene resin (LDPE), linear low density polyethylene resin (LLDPE), or metallocene resin A linear low-density polyethylene resin (M-LLDPE) can be preferably used. Among them, from the viewpoint of molding properties, a metallocene linear low-density polyethylene resin (M-LLDPE) can be particularly preferably used as the sealing material composition for the skin layer.

The density of the polyethylene-based resin used as the base resin for the skin layer is 0.875 g/cm ³ or more and 0.910 g/cm ³ or less, and more preferably 0.899 g/cm ³ or less. By setting the density of the base resin for the skin layer within the above range, the adhesion of the sealing member can be maintained within a preferable range.

The melting point of the polyethylene-based resin used as the base resin for the skin layer is preferably 50°C or higher and 100°C or lower, and more preferably 55°C or higher and 95°C or lower. By setting it within the above range, the adhesion of the sealing member can be further reliably improved.

The melt mass flow rate (MFR) of the polyethylene resin used as the base resin for the skin layer is preferably 1.0 g/10 min or more and 7.0 g/10 min or less at 190° C. under a load of 2.16 kg. It is more preferably 1.5 g/10 minutes or more and 6.0 g/10 minutes or less. By setting the MFR of the base resin for the skin layer within the above range, the adhesion of the sealing member can be maintained within a more preferable range. In addition, it is possible to contribute to the improvement of the productivity of the sealing member by sufficiently improving the processability at the time of film formation.

The content of the base resin with respect to the total resin components for the skin layer is 60% by mass or more and 99% by mass or less, preferably 90% by mass or more and 99% by mass or less. As long as it contains the base resin within the above range, it may contain other resins.

For all of the encapsulant compositions described above, a silane copolymer obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as comonomers may be added to each encapsulant composition, if necessary. It is more preferable to contain a fixed amount. Such a graft copolymer increases the degree of freedom of the silanol group that contributes to adhesive strength, and thus can improve the adhesiveness of the sealing member to other members.

Examples of silane copolymers include silane copolymers described in JP-A-2003-46105. By using the silane copolymer as a component of the encapsulant composition, excellent strength, durability, etc., and excellent weather resistance, heat resistance, water resistance, light resistance, and other characteristics can be obtained. It is possible to stably obtain a sealing member at a low cost, which has extremely excellent heat-sealability without being affected by manufacturing conditions such as thermocompression bonding when arranging the sealing member.

As the silane copolymer, any of random copolymers, alternating copolymers, block copolymers, and graft copolymers can be preferably used, but graft copolymers are preferred. More preferred is a graft copolymer in which a polyethylene for polymerization is used as a main chain and an ethylenically unsaturated silane compound is polymerized as a side chain. In such a graft copolymer, the degree of freedom of silanol groups that contribute to adhesive strength is increased, so that the adhesiveness of the sealing member can be improved.

The content of the ethylenically unsaturated silane compound in forming the copolymer of the α-olefin and the ethylenically unsaturated silane compound is, for example, 0.001% by mass or more and 15% of the total mass of the copolymer. % by mass or less, preferably 0.01% by mass or more and 10% by mass or less, particularly preferably 0.05% by mass or more and 5% by mass or less. When the content of the ethylenically unsaturated silane compound constituting the copolymer of the α-olefin and the ethylenically unsaturated silane compound is high, the mechanical strength and heat resistance are excellent. , tensile strain, and heat-sealability.

The content of the silane copolymer in the total resin components of the sealing material composition is 0% by mass or more and 20% by mass or less in the sealing material composition for the core layer, and the amount of the sealing material for the skin layer is In the 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 5% by mass or more of the silane copolymer. The silane modification amount in the above silane copolymer is preferably about 0.1% by mass or more and 2.0% by mass or less. The preferred content range of the silane copolymer in the sealing material composition is based on the premise that the silane modification amount is within this range, and fine adjustment can be made as appropriate according to the variation in the modification amount. desirable.

Additives such as antioxidants and light stabilizers may be added to all layers of the sealing member.
In addition, an adhesion improver can be added as appropriate. Addition of an adhesion improver can increase adhesion durability with other members. As the adhesion improver, known silane coupling agents can be used, and vinyltrimethoxysilane, vinyltriethoxysilane having a vinyl group, a silane coupling agent having an epoxy group, or a silane having a mercapto group. A coupling agent can be used particularly preferably.

(6) Total light transmittance The sealing member in the present embodiment is not particularly limited as long as it can exhibit the function as a surface light emitting device, but it is preferably 70% or more, especially 80% or more. preferable. The total light transmittance of the sealing member can be measured, for example, by a method conforming to JIS K7361-1:1997.

(7) Method for forming sealing member As described above, the sealing member in the present embodiment is formed using a sealing member sheet composed of a sealing material composition containing the thermoplastic resin and other components. can do.
The sealing member sheet is obtained by molding the sealing material composition by a conventionally known method to form a sheet.

When the sealing member is a multi-layer member, the core layer and skin layer sealing material compositions are used to form a core layer and a skin layer arranged on one surface of the core layer with a predetermined thickness. By molding a multi-layer film having a layered structure, a sealing member 5 having a two-layered structure of a core layer 51 and a skin layer 52 can be manufactured, as shown in FIG. 3(a), for example. Alternatively, it is possible to form a multilayer film having a three-layer structure in which skin layers are arranged on both surfaces of a core layer. As a result, for example, as shown in FIG. 3B, the sealing member 5 having a three-layer structure of the skin layer 52, the core layer 51, and the skin layer 52 can be manufactured. 3 are the same as those in FIG. 1 except for the sealing member 5 and the reflective layer R, and therefore descriptions thereof are omitted here.

2. Warpage Prevention Layer The warpage prevention layer in this embodiment is a layer arranged between the sealing member and the diffusion member described later.

In this embodiment, warping can be prevented by setting the coefficient of linear expansion of the material constituting the warp-preventing layer to a predetermined range in a high-temperature region. The reason why warping can be prevented by setting the coefficient of linear expansion of the material constituting the warp preventing layer within a predetermined range is as follows.

That is, when manufacturing a surface emitting device, a step of thermocompression bonding the sealing member and the LED substrate may be included, but the behavior of the sealing member shrinks more than the LED substrate during cooling after the thermocompression bonding. At this time, since the anti-warp layer having a small coefficient of linear expansion is arranged on the opposite side of the sealing member from the LED substrate, it is possible to reduce the degree of shrinkage on the side of the sealing member. , it is possible to suppress the occurrence of warpage.

In addition, in this embodiment, by disposing the anti-warp layer, it is possible to suppress the deformation of the sealing member that occurs when air bubbles are generated at the site where the air bubbles are generated. Moreover, it is possible to prevent air bubbles from being generated between the sealing member and the LED substrate. In particular, the anti-warp layer having a predetermined elastic modulus and a predetermined melting point can effectively obtain the above effects.

a) Coefficient of linear expansion The coefficient of linear expansion of the material constituting the anti-warp layer in the present disclosure is set within the range of −15×10 ⁻⁶ /° C. or more and 10×10 ⁻⁶ /° C. or less.
In the present disclosure, it is particularly preferable that the lower limit of the coefficient of linear expansion is −10×10 ⁻⁶ /° C. or more. On the other hand, the upper limit is preferably 5×10 ⁻⁶ /° C. or less, particularly preferably 0 or less. That is, it is preferably -10×10 ^-6 /°C or higher and 5×10 ^-6 /°C or lower, and particularly preferably -10×10 ^-6 /°C or higher and 0×10 ^-6 /°C or lower. On the other hand, considering the materials used, it is usually -10×10 ⁻⁶ /° C. or more and 5×10 ⁻⁶ /° C. or less. If it is smaller than this, it will cause reverse warpage. On the other hand, if it is larger than this, the anti-warping effect will be insufficient.

As a method for measuring the linear expansion coefficient in this embodiment, the following method is used.
For a sheet cut to 5 mm × 20 mm, after heating in accordance with JIS K 7197: 2012, the dimensional change during cooling to room temperature was measured, and the coefficient of linear expansion from 100 ° C. to 25 ° C. was averaged and calculated. . The coefficient of linear expansion here is a positive value during contraction and a negative value during expansion. The measurement was performed using the following measurement apparatus and measurement conditions.
・Measuring device: Thermomechanical device manufactured by Seiko Instruments (TMA/SS-6000)
・Constant load tensile mode: 0.1 mN
・Measurement temperature range: -50°C to 160°C ・Linear expansion coefficient calculation temperature range: 25°C to 100°C

b) Modulus of Elasticity The modulus of elasticity of the anti-warp layer used in this embodiment is preferably 500 MPa or higher, particularly preferably 1000 MPa or higher, and more preferably 4000 MPa or higher.
This is because if the elastic modulus is lower than the above range, the effect of suppressing bubble generation and the effect of preventing warpage are reduced. It should be noted that the pressure is 5500 MPa or less in consideration of commonly used materials.

As a method for measuring the elastic modulus in this embodiment, the following tensile measurement is performed.
(Measuring method)
・Measuring device: Universal material testing machine 5565 manufactured by Instron
・Load cell: 1kN
・Sample width: 10 mm
・Distance between chucks: 50mm
・Speed: 300mm/min

c) Thickness The thickness of the anti-warpage layer in this embodiment is preferably in the range of 35 µm to 188 µm, more preferably in the range of 50 µm to 150 µm, particularly preferably in the range of 100 µm to 125 µm. Within the above range, it is possible to obtain the effect of preventing warpage and the effect of suppressing the generation of bubbles, and does not hinder the compactness of the device.

d) Transmittance and Haze Value The haze value of the anti-warp layer in this embodiment is preferably 40% or less, more preferably 20% or less, particularly preferably 10% or less.
Within the above range, it is possible to improve the in-plane uniformity of luminance. If the haze value exceeds the above range, the light is absorbed while being scattered inside the sealing member, resulting in a decrease in brightness.
As a method for measuring the haze value, the same method as the method for measuring the haze value of the sealing member can be used.

On the other hand, the total light transmittance of the anti-warp layer in this embodiment is preferably 80% or more, particularly preferably 90% or more. With such a high total light transmittance, it is possible to prevent the brightness of the surface emitting device from lowering.

Here, the total light transmittance of the anti-warp layer can be measured according to JIS K7361-1, and can be measured with a haze meter HM150 manufactured by Murakami Color Research Laboratory.

e) Melting Point The melting point of the anti-warp layer in this embodiment is preferably 140° C. or higher, particularly preferably 260° C. or higher. Note that the upper limit is 350° C. or less in consideration of commonly used materials and the like.
The melting point in this embodiment can be measured, for example, by differential scanning calorimetry (DSC) according to the method for measuring the transition temperature of plastics (JISK7121).

In this embodiment, since the anti-warp layer has the melting point described above, it is possible to effectively prevent the generation of air bubbles even when the surface emitting device is used for a long time in a high temperature environment.

f) Material The material constituting the anti-warp layer used in this embodiment is not particularly limited as long as it has the above properties, but examples include polyolefin, polyester, celluloses, acrylic resin, and polyimide resin. can be done. Examples of polyolefins include polypropylene (PP). Examples of polyester include polytetraethylene terephthalate (PET) and polyethylene naphthalate (PEN). Examples of celluloses include triacetyl cellulose (TAC).
In the present embodiment, PP and PET are particularly preferred from the viewpoint of versatility and the like.

g) Others In this embodiment, it is preferable that the anti-warp layer and the sealing member are in close contact with each other. This is because the anti-warping effect can be exhibited more efficiently. In the present embodiment, "the anti-warp layer and the sealing member are in close contact" refers to a state in which they do not separate due to their own weight when they are taken out.
Specifically, the adhesion strength is preferably 1N or more. As a method for measuring adhesive strength, the following method can be used in accordance with JIS K 6854-2: 1999.

(Measuring method)
The sealing member adhering to the PCB substrate is cut into a width of 25 mm, and a vertical peeling test (300 mm/min) is performed using a peeling tester (Tensilon universal tester RTF-1150-H) to measure the adhesion strength.

In order to bring the warp prevention layer and the sealing member into close contact, a method of arranging them with an adhesive layer interposed therebetween, a method of melting them by thermocompression bonding, and the like can be mentioned.

3. LED Substrate The LED substrate in this embodiment is a member in which a plurality of LED elements are arranged on one side of a support substrate.

(1) LED element The LED element is a member arranged on one side of the support substrate and functions as a light source.
The LED element is not particularly limited as long as it can irradiate white light in the case of a surface emitting device, for example.

The LED element can be a chip-shaped LED element. The form of the LED element may be, for example, a light-emitting part (also called an LED chip) itself, or a package LED (also called a chip LED) such as a surface-mount type or a chip-on-board type. A packaged LED can have, for example, a light-emitting portion and a protective portion that covers the light-emitting portion and contains resin. Specifically, when the LED element is the light emitting part itself, for example, a blue LED element, an ultraviolet LED element, or an infrared LED element can be used as the LED element. Moreover, when the LED element is a package LED, for example, a white LED element can be used as the LED element.

When the surface emitting device of the present embodiment combines an LED element and the wavelength conversion member to irradiate white light, the LED element is a blue LED element, an ultraviolet LED element, or an infrared LED element. is preferred. A blue LED element can generate white light, for example, by combining it with a yellow phosphor, or by combining it with a red phosphor and a green phosphor. In addition, ultraviolet LED elements can generate white light by combining, for example, red phosphors, green phosphors, and blue phosphors. Among them, it is preferable that the LED element is a blue LED element. This is because the surface emitting device of this embodiment can irradiate white light with high luminance.

Also, when the LED element is a white LED element, the white LED element is appropriately selected according to the light emission method of the white LED element. Examples of the light emission method of the white LED element include a combination of a red LED, a green LED, and a blue LED, a combination of a blue LED, a red phosphor, and a green phosphor, a combination of a blue LED and a yellow phosphor, and an ultraviolet LED. A combination of a red phosphor, a green phosphor, and a blue phosphor can be used.

Therefore, the white LED element may have, for example, a red LED light-emitting portion, a green LED light-emitting portion, and a blue LED light-emitting portion. It may have a blue LED light emitting portion and a protective portion containing a yellow phosphor, and may have an ultraviolet LED light emitting portion and a red phosphor, a green phosphor and a blue phosphor. You may have a protection part.

Among them, the white LED element has a blue LED light-emitting portion and a protective portion containing a red phosphor and a green phosphor, has a blue LED light-emitting portion and a protective portion containing a yellow phosphor, or emits ultraviolet LED light. It is preferable to have a portion and a protective portion containing a red phosphor, a green phosphor and a blue phosphor.

Among these, the white LED element may have a blue LED light emitting portion and a protective portion containing a red phosphor and a green phosphor, or may have a blue LED light emitting portion and a protective portion containing a yellow phosphor. preferable. This is because the surface emitting device of this embodiment can irradiate white light with high luminance.
The structure of the LED element can be the same as that of a general LED element.

The LED elements are usually arranged at regular intervals on one side of the support substrate. The arrangement of the LED elements is appropriately selected according to the application and size of the surface emitting device of this embodiment, the size of the LED elements, and the like. Also, the arrangement density of the LED elements is appropriately selected according to the application and size of the surface emitting device of this embodiment, the size of the LED elements, and the like.

The size (chip size) of the LED element can be a general chip size, but a chip size called mini-LED is preferable. The size of the LED element may be, for example, several hundred micrometers square or several tens of micrometers square. Specifically, the size of the LED element can be 100 μm square or more and 2000 μm square or less. Due to the small size of the LED elements, the LED elements can be arranged at a high density, that is, the intervals (pitch) between the LED elements can be reduced, and the distance between the LED substrate and the diffusion member can be shortened. This is because the thickness can be reduced. This makes it possible to reduce the thickness and weight of the surface emitting device.

(2) Support Substrate The support substrate in this embodiment is a member that supports the above-described LED element, sealing member, diffusion member, and the like.

The support substrate may be transparent or opaque. Moreover, the support substrate may have flexibility or may have rigidity. The material of the support substrate may be an organic material, an inorganic material, or a composite material obtained by combining both an organic material and an inorganic material.

When the material of the support substrate is an organic material, a resin substrate can be used as the support substrate. On the other hand, when the material of the support substrate is an inorganic material, a ceramic substrate or a glass substrate can be used as the support substrate. Further, when the material of the support substrate is a composite material, a glass epoxy substrate can be used as the support substrate. A metal core substrate, for example, can also be used as the support substrate. A printed circuit board on which a circuit is formed by printing can also be used as the support substrate.

The thickness of the support substrate is not particularly limited, and is appropriately selected according to the presence or absence of flexibility or rigidity, the application and size of the surface emitting device of this embodiment, and the like.
In this embodiment, the support substrate has a lower coefficient of linear expansion than the sealing member described above. For this reason, as described above, there arises a problem that warpage occurs after the sealing member is thermocompression bonded in the manufacturing process.

The coefficient of linear expansion of the support substrate used in this embodiment is usually in the range of 5×10 ^-6 /°C. to 100×10 ^-6 /°C.

(3) Others The LED substrate in this embodiment is not particularly limited as long as it has the above-described supporting substrate and LED elements, and can have any necessary configuration as appropriate. Examples of such a configuration include a wiring portion, a terminal portion, an insulating layer, a reflective layer, a heat radiating member, and the like. Each configuration can be the same as that used for known LED substrates.

The wiring part is electrically connected to the LED element. The wiring part is usually arranged in a pattern. Also, the wiring portion can be arranged on the supporting substrate via an adhesive layer. A metal material, a conductive polymer material, or the like can be used as the material of the wiring portion.

The wiring part is electrically connected to the LED element by a joint part. As a material for the joint, a bonding agent or solder having a conductive material such as a metal or a conductive polymer can be used.

A reflective layer can be arranged on the surface of the support substrate on which the LED elements are arranged and in areas other than the LED element mounting area. For example, the light reflected by the second layer of the diffusing member can be reflected by the reflective layer of the support substrate and made to enter the first layer of the diffusing member again, thereby increasing the light utilization efficiency. .

The reflective layer can be similar to reflective layers commonly used in LED substrates. Specifically, the reflective layer includes a white resin film containing metal particles, inorganic particles or a pigment and a resin, a metal film, a porous film, and the like. The thickness of the reflective layer is not particularly limited as long as the desired reflectance is obtained, and is set as appropriate.
A method for forming the LED substrate can be the same as a known forming method.

4. Diffusion Member The diffusion member is arranged on the side of the sealing member opposite to the LED substrate side. The diffusion member is not particularly limited as long as it has the function of diffusing the light emitted from the LED element and emitting it uniformly in the plane direction, but the following first diffusion member, second diffusion member, and A third diffusion member is included.

4.1 First Diffusion Member The first diffusion member usually has at least a resin layer in which a diffusing agent is dispersed. The diffusion member may be, for example, a resin sheet in which a diffusing agent is dispersed, or a laminate having a resin layer in which a diffusing agent is dispersed on a transparent substrate, but the former is more preferable. The resin contained in the resin layer is not particularly limited as long as it can disperse the diffusing agent, but is preferably a thermoplastic resin. This is because the diffusion member can be formed using the resin sheet in which the diffusing agent is dispersed, so that the flatness can be improved.

The thermoplastic resin used for the diffusing member is not particularly limited as long as it has high light transmittance, and those commonly used in the field of display devices can be used.

The material of the diffusing agent is not particularly limited as long as it can diffuse the light from the LED element. For example, it may be an organic material or an inorganic material. When the material of the diffusing agent is an organic material, for example, polymethyl methacrylate (PMMA) can be used. On the other hand, when the material of the diffusing agent is an inorganic material, TiO ₂ , SiO ₂ , Al ₂ O ₃ , silicon and the like can be mentioned.

The refractive index of the diffusing agent is not particularly limited as long as it can diffuse the light from the LED element, but is, for example, 1.4 or more and 2 or less. Such a refractive index can be measured by an Abbe refractometer, Becke method, minimum deflection angle method, deflection angle analysis, mode line method, ellipsometry method, or the like. The shape of the diffusing agent can be, for example, particulate. The average particle size of the diffusing agent is, for example, 1 μm or more and 100 μm or less.

The proportion of the diffusing agent in the diffusing member is not particularly limited as long as the light from the LED elements can be diffused, and is, for example, 40% by weight or more and 60% by weight or less.

4.2 Second diffusion member The second diffusion member is a member having a first layer and a second layer in this order from the LED substrate side, and the first layer is a light-transmitting layer. and light diffusing properties, and the reflectance of the second layer increases as the absolute value of the incident angle of light with respect to the first layer side surface of the second layer decreases. It is a member whose transmittance increases as the absolute value of the incident angle of light with respect to the surface on the first layer side increases. In this embodiment, by including the above-described diffusing member, it is possible to further improve the in-plane uniformity of luminance and achieve a reduction in thickness. Also, cost and power consumption can be reduced.

The second diffusion member will be described below with reference to the drawings. FIG. 4 is a schematic cross-sectional view showing an example of the second diffusion member. As illustrated in FIG. 4, the diffusion member 11 has a first layer 12 and a second layer 13 in this order. The first layer 12 has light transmittance and light diffusion properties, and transmits and diffuses the lights L1 and L2 incident from the surface 12A opposite to the second layer 13 side surface of the first layer 12 . In addition, the reflectance of the second layer 13 increases as the absolute value of the incident angle of light with respect to the surface 13A of the second layer 13 on the side of the first layer 12 decreases. The transmittance increases as the absolute value of the incident angle of light with respect to the surface 13A increases. Therefore, in the second layer 13, the light L1 incident at a low incident angle θ1 is reflected to the surface 13A of the second layer 13 on the side of the first layer 12, and the surface 13A of the second layer 13 on the side of the first layer 2 is reflected. can transmit light L2 incident at a high incident angle θ2 with respect to . The low incident angle means that the absolute value of the incident angle is small, and the high incident angle means that the absolute value of the incident angle is large.

FIG. 5 is a schematic cross-sectional view showing an example of the surface emitting device of this embodiment comprising the second diffusion member shown in FIG. As illustrated in FIG. 5, the surface emitting device 10 includes an LED substrate 4 having LED elements 3 arranged on one surface of a support substrate 2, and an LED substrate 4 arranged on the surface of the LED substrate 4 on the LED element 3 side. It has a sealing member 5 that seals the element 3 and a diffusion member 11 arranged on the side of the sealing member 5 opposite to the LED substrate 4 side. The diffusion member 11 is arranged so that the surface 11A on the side of the first layer 12 faces the sealing member 5 .

As shown in FIG. 4, the light incident from the surface 11A of the diffusion member 11 on the side of the first layer 12 is diffused by the first layer 12, and of the light transmitted through the first layer 12 and diffused, the second Light L1 incident on the surface 13A of the layer 13 on the side of the first layer 12 at a low incident angle θ1 is reflected by the surface 13A of the second layer 13 on the side of the first layer 12 as shown in FIG. It can be incident on the first layer 12 again and diffused. Among the lights transmitted through the first layer 12 and diffused, the lights L2 and L2' incident on the surface 13A of the second layer 13 on the side of the first layer 12 at a high incident angle θ2 are 13 and emitted from the surface 11B of the diffusion member 11 on the second layer 13 side.

In addition, by combining the first layer and the second layer, the light incident from the surface of the diffusing member on the first layer side, especially the light incident on the surface of the diffusing member on the first layer side at a low angle of incidence, can be Since the light can also pass through the first layer and be diffused, it can be emitted from the surface of the diffusion member on the second layer side at a high output angle. Therefore, a surface emitting device (particularly, a direct type LED backlight) having such a diffusing member can diffuse the light emitted from the LED elements over the entire light emitting surface, further improving the in-plane uniformity of luminance. can be improved.

In addition, by combining the first layer and the second layer, light that is incident at a low incident angle from the surface of the diffusion member on the first layer side can be transmitted through the first layer many times. It is possible to lengthen the optical path length from the incident light from the surface of the member on the first layer side to the light emitted from the surface on the second layer side of the diffusing member. As a result, part of the light emitted from the LED element and then emitted from the surface of the diffusion member on the second layer side can be emitted from a position away from the LED element in the in-plane direction instead of directly above the LED element. become able to.

(1) First Layer The first layer in this embodiment is a member that is disposed on one side of the second layer described later and has light transmission and light diffusion properties. As for the light transmittance of the first layer, for example, the total light transmittance of the first layer is preferably 50% or more, more preferably 70% or more, and particularly preferably 90% or more. . When the total light transmittance of the first layer is within the above range, the brightness of the surface emitting device of this embodiment can be increased.

The total light transmittance of the first layer can be measured, for example, by a method conforming to JIS K7361-1:1997.

The light diffusing property of the first layer may be, for example, light diffusing property that diffuses light randomly, or light diffusing property that diffuses light mainly in a specific direction. The light diffusing property of diffusing light mainly in a specific direction is the property of deflecting light, that is, the property of changing the traveling direction of light. As the light diffusion property of the first layer, if the light diffusion property is to randomly diffuse light, for example, the diffusion angle of the light incident on the first layer can be 10 ° or more, and 15 ° or more. It may be 20° or more. Further, the diffusion angle of light incident on the first layer can be, for example, 85° or less, may be 60° or less, or may be 50° or less. When the diffusion angle is within the above range, the in-plane uniformity of luminance of the surface light-emitting device of this embodiment can be further improved.

Here, the diffusion angle will be explained. FIG. 6 is a graph illustrating the transmitted light intensity distribution, and is a diagram for explaining the diffusion angle. In this specification, light is vertically incident on one surface of the first layer constituting the diffusion member, and the maximum transmitted light intensity Imax of the light emitted from the other surface of the first layer The full width at half maximum (FWHM), which is the difference between the two angles such that , is defined as the diffusion angle α.

The diffusion angle can be measured using a goniophotometer or a goniospectrophotometer. A goniophotometer GP-200 manufactured by Murakami Color Research Laboratory Co., Ltd. can be used to measure the diffusion angle.

The first layer is not particularly limited as long as it has the above-described light transmittance and light diffusion properties, and includes a transmissive diffraction grating, a microlens array, a diffusing agent-containing resin film containing a diffusing agent and a resin. etc. Specifically, when the first layer has a light diffusing property of diffusing light mainly in a specific direction, a transmissive diffraction grating and a microlens array can be used. On the other hand, when the first layer has a light diffusing property of randomly diffusing light, a diffusing agent-containing resin film can be used. Among them, transmission diffraction gratings and microlens arrays are preferable from the viewpoint of light diffusion. The transmission type diffraction grating is also called a transmission type diffraction optical element (DOE: Diffractive Optical Elements).

When the first layer is a transmission type diffraction grating, the transmission type diffraction grating is not particularly limited as long as it has the above-described light transmittance and light diffusion properties. The pitch and the like of the transmissive diffraction grating are adjusted appropriately as long as the above-described light transmittance and light diffusibility are obtained. Specifically, when the wavelengths emitted by the LED elements are single colors such as red, green, and blue, it is possible to effectively bend the light from the LED elements by setting the pitch according to each wavelength. is.

The material constituting the transmission diffraction grating may be any material that can provide the transmission diffraction grating having the above-described light transmittance and light diffusing properties. can be done. Also, the method of forming the transmission diffraction grating can be the same as the method of forming a general transmission diffraction grating.

When the first layer is a microlens array, the microlens array is not particularly limited as long as it has the above-described light transmittance and light diffusion properties. The shape, pitch, size, and the like of the microlenses are adjusted appropriately as long as the above-described light transmittance and light diffusion are obtained. As a material for forming the microlens, any material can be used as long as the microlens having the above-described light transmittance and light diffusing properties can be obtained, and materials generally used for microlenses can be employed. Also, the method for forming the microlens can be the same as the method for forming a general microlens.

When the first layer is a diffusing agent-containing resin film, the diffusing agent-containing resin film is not particularly limited as long as it has the above-described light transmittance and light diffusibility.

The first layer may have a structure capable of exhibiting light diffusing properties, for example, the entire layer may exhibit light diffusing properties, and the surface may exhibit light diffusing properties. can be anything. For example, a relief-type diffraction grating and a microlens array can be cited as examples of a surface that exhibits light diffusing properties. On the other hand, for example, a volume type diffraction grating and a diffusing agent-containing resin film can be cited as examples of materials that exhibit light diffusibility in the entire layer. As a method of laminating the first layer and the second layer, for example, a method of bonding the first layer and the second layer via an adhesive layer or an adhesive layer, or a method of bonding the first layer directly to one surface of the second layer. A forming method and the like can be mentioned. Examples of methods for directly forming the first layer on one side of the second layer include a printing method and resin molding using a mold.

(2) Second layer The second layer in this embodiment is arranged on one surface side of the first layer, and the absolute value of the incident angle of light with respect to the surface of the second layer on the first layer side is small. The incident angle dependence of the reflectance such that the reflectance increases as it increases, and the transmission such that the transmittance increases as the absolute value of the incident angle of light with respect to the surface of the second layer on the first layer side increases It is a member having the incident angle dependence of the index.

The second layer has incident angle dependence of reflectance such that the reflectance increases as the absolute value of the incident angle of light with respect to the first layer side surface of the second layer decreases. That is, the reflectance of light incident on the first layer side surface of the second layer at a low incident angle is the reflectance of light incident on the first layer side surface of the second layer at a high incident angle be larger than Above all, it is preferable that the reflectance of light incident on the surface of the second layer on the first layer side at a low incident angle is high.

Specifically, the regular reflectance of visible light incident on the surface of the second layer on the first layer side within an incident angle of ±60° is preferably 50% or more and less than 100%, especially 80%. It is preferably 90% or more and less than 100%, particularly preferably 90% or more and less than 100%. It is preferable that the specular reflectance of visible light satisfies the above range at all incident angles within ±60°. When the regular reflectance is within the above range, the in-plane uniformity of luminance of the surface light-emitting device of the present embodiment can be further improved.

In addition, the average value of the regular reflectance of visible light incident on the surface of the second layer on the first layer side at an incident angle of ± 60 ° is preferably, for example, 80% or more and 99% or less. It is preferably 90% or more and 97% or less. In addition, the average value of the specular reflectance means the average value of the specular reflectance of visible light at each incident angle. When the average value of the regular reflectance is within the above range, the in-plane uniformity of luminance of the surface emitting device in this embodiment can be further improved.

In addition, the regular reflectance of visible light incident on the surface of the second layer on the first layer side at an incident angle of 0° (perpendicularly incident) is preferably, for example, 80% or more and less than 100%, Among them, it is preferably 90% or more and less than 100%, and particularly preferably 95% or more and less than 100%. When the regular reflectance is within the above range, the in-plane uniformity of luminance of the surface light-emitting device of the present embodiment can be further improved.

In this specification, "visible light" means light with a wavelength of 380 nm or more and 780 nm or less. Also, the regular reflectance can be measured using a variable angle photometer or a variable angle spectrophotometer. A goniophotometer GP-200 manufactured by Murakami Color Research Laboratory Co., Ltd. can be used to measure the specular reflectance.

The second layer has an incident angle dependency of transmittance such that the transmittance increases as the absolute value of the incident angle of light with respect to the surface of the second layer on the first layer side increases. That is, the transmittance of light incident on the surface of the second layer on the first layer side at a high incident angle is the transmittance of light incident on the surface of the second layer on the first layer side at a low incident angle. be larger than Above all, it is preferable that the transmittance of light incident on the surface of the second layer on the first layer side at a high incident angle is high. Specifically, the total light transmittance of light incident on the surface of the second layer on the first layer side at an incident angle of 70° or more and less than 90° is preferably 30% or more, especially 40% or more. is preferable, and 50% or more is particularly preferable. The total light transmittance preferably satisfies the above range at all incident angles of 70° or more and less than 90°. Further, when the absolute value of the incident angle is 70° or more and less than 90°, the total light transmittance preferably satisfies the above range. When the total light transmittance is within the above range, it is possible to further improve the in-plane uniformity of luminance of the surface light-emitting device of the present embodiment.

The total light transmittance of the second layer can be measured, for example, using a goniophotometer or a goniospectral colorimeter by a method conforming to JIS K7361-1:1997. For the measurement of the total light transmittance, an ultraviolet-visible-near-infrared spectrophotometer V-7200 manufactured by JASCO Corporation can be used.

The second layer is not particularly limited as long as it has the above-described incident angle dependence of reflectance and transmittance, and various configurations having the above-described incident angle dependence of reflectance and transmittance can be used. can be adopted. The second layer includes, for example, a dielectric multilayer film, or a patterned first reflective film and a patterned second reflective film in this order from the first layer side. Examples include a reflective structure, a reflective diffraction grating, and the like, in which the openings of the two reflective films are positioned so as not to overlap each other in plan view, and the first reflective film and the second reflective film are spaced apart in the thickness direction.

A case where the second layer is a dielectric multilayer film, a reflective structure, or a reflective diffraction grating will be described below.

a) Dielectric multilayer film When the second layer is a dielectric multilayer film, the dielectric multilayer film may be, for example, a multilayer film of an inorganic compound in which inorganic layers having different refractive indices are alternately laminated, or a multilayer film having different refractive indices. A resin multilayer film in which resin layers are alternately laminated can be used.

(Multilayer film of inorganic compound)
When the dielectric multilayer film is an inorganic compound multilayer film in which inorganic layers with different refractive indices are alternately laminated, the inorganic compound multilayer film has the above-described incident angle dependence of reflectance and transmittance. is not particularly limited.

Among the inorganic layers having different refractive indices, the inorganic compound contained in the high refractive index inorganic layer having a high refractive index may have a refractive index of 1.7 or more, such as 1.7 or more and 2.5 or less. There may be. Examples of such inorganic compounds include titanium oxide, zirconium oxide, tantalum pentoxide, niobium pentoxide, lanthanum oxide, yttrium oxide, zinc oxide, zinc sulfide, and indium oxide, and titanium oxide, tin oxide, and cerium oxide. Examples include those containing a small amount.

Further, among the inorganic layers having different refractive indices, the inorganic compound contained in the low refractive index inorganic layer having a low refractive index may be, for example, a refractive index of 1.6 or less, 1.2 or more and 1.6 or more. It may be below. Examples of such inorganic compounds include silica, alumina, lanthanum fluoride, magnesium fluoride, and sodium aluminum hexafluoride.

The number of layers of the high-refractive-index inorganic layer and the low-refractive-index inorganic layer is adjusted appropriately as long as the above-described incident angle dependency of reflectance and transmittance can be obtained. Specifically, the total number of lamination of the high refractive index inorganic layers and the low refractive index inorganic layers can be 4 or more. The upper limit of the total number of layers is not particularly limited, but it can be set to 24 layers or less, for example, because the number of steps increases as the number of layers increases.

The thickness of the inorganic compound multilayer film should be sufficient to obtain the above-described incident angle dependency of reflectance and transmittance, and can be, for example, 0.5 μm or more and 10 μm or less. Examples of the method for forming a multilayer film of an inorganic compound include a method of alternately laminating a high refractive index inorganic layer and a low refractive index inorganic layer by a CVD method, a sputtering method, a vacuum deposition method, a wet coating method, or the like.

(Resin multilayer film)
When the dielectric multilayer film is a resin multilayer film in which resin layers with different refractive indices are alternately laminated, the resin multilayer film may have the above-described incident angle dependency of reflectance and transmittance. is not particularly limited.

Examples of resins that make up the resin layer include thermoplastic resins and thermosetting resins. Of these, thermoplastic resins are preferred because of their good moldability.

The resin layer contains various additives such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, viscosity reducers, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, and refractive index adjusters. A dopant for may be added.

Thermoplastic resins include polyolefin resins, alicyclic polyolefin resins, polyamide resins, aramid resins, polyester resins, polycarbonate resins, polyarylate resins, polyacetal resins, polyphenylene sulfide resins, tetrafluoroethylene resins, trifluoroethylene resins, Fluorine resins such as trifluoroethylene chloride resin, tetrafluoroethylene-hexafluoropropylene copolymer, and vinylidene fluoride resin, acrylic resin, methacrylic resin, polyacetal resin, polyglycolic acid resin, and polylactic acid resin can be used. can. Examples of the polyolefin resin include polyethylene, polypropylene, polystyrene, and polymethylpentene. Polyamide resins include nylon 6 and nylon 66. Furthermore, polyester resins include polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polybutylsuccinate, and polyethylene-2,6-naphthalate. In the present disclosure, among others, polyester is more preferable from the viewpoint of strength, heat resistance, and transparency.

In the present specification, polyester refers to homopolyesters and copolyesters that are polycondensates of a dicarboxylic acid component skeleton and a diol component skeleton. Examples of homopolyesters include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, and polyethylene diphenylate. Among them, polyethylene terephthalate is preferable because it is inexpensive and can be used in a wide variety of applications.

In this specification, the copolyester is defined as a polycondensate composed of at least three components selected from the following components having a dicarboxylic acid skeleton and components having a diol skeleton. Components having a dicarboxylic acid skeleton include terephthalic acid, isophthalic acid, phthalic acid, 1,4-naphthalenedicarboxylic acid, 1,5-naphthalenedicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 4,4-diphenyldicarboxylic acid, 4,4-diphenylsulfonedicarboxylic acid, adipic acid, sebacic acid, dimer acid, cyclohexanedicarboxylic acid and their ester derivatives. Components having a glycol skeleton include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentadiol, diethylene glycol, polyalkylene glycol, 2,2-bis (4-β-hydroxyethoxyphenyl)propane, isosorbate, 1,4-cyclohexanedimethanol, spiroglycol.

Among the resin layers having different refractive indexes, the difference in in-plane average refractive index between the high refractive index resin layer with a high refractive index and the low refractive index resin layer with a low refractive index is preferably 0.03 or more, and more It is preferably 0.05 or more, more preferably 0.1 or more. If the difference in in-plane average refractive index is too small, a sufficient reflectance may not be obtained.

Further, the difference between the in-plane average refractive index and the thickness direction refractive index of the high refractive index resin layer is preferably 0.03 or more, and the difference between the in-plane average refractive index and the thickness direction refractive index of the low refractive index resin layer is preferably is preferably 0.03 or less. In this case, even if the incident angle increases, the reflectance at the reflection peak is less likely to decrease.

As a preferable combination of the high refractive index resin used for the high refractive index resin layer and the low refractive index resin used for the low refractive index resin layer, first, the difference in SP value between the high refractive index resin and the low refractive index resin is preferably 1.0 or less. When the absolute value of the SP value difference is within the above range, delamination is less likely to occur. In this case, it is more preferable that the high refractive index resin and the low refractive index resin contain the same basic skeleton. Here, the basic skeleton means a repeating unit that constitutes the resin. For example, when one resin is polyethylene terephthalate, ethylene terephthalate is the basic skeleton. Further, for example, when one resin is polyethylene, ethylene is the basic skeleton. When the high-refractive-index resin and the low-refractive-index resin are resins containing the same basic skeleton, separation between layers is even more difficult to occur.

As a preferable combination of the high refractive index resin used for the high refractive index resin layer and the low refractive index resin used for the low refractive index layer, secondly, the difference in glass transition temperature between the high refractive index resin and the low refractive index resin is preferably 20° C. or less. If the difference in glass transition temperature is too large, thickness uniformity may be poor when forming a laminated film of a high-refractive-index resin layer and a low-refractive-index resin layer. In addition, overstretching may occur when forming the laminated film.

Also, it is preferable that the high refractive index resin is polyethylene terephthalate or polyethylene naphthalate, and the low refractive index resin is polyester containing spiroglycol. Here, the spiroglycol-containing polyester means a copolyester or homopolyester obtained by copolymerizing spiroglycol, or a polyester obtained by blending them. A spiroglycol-containing polyester has a small difference in glass transition temperature from that of polyethylene terephthalate or polyethylene naphthalate, and thus is less prone to overstretching during molding and less likely to cause delamination, which is preferable.

More preferably, the high refractive index resin is polyethylene terephthalate or polyethylene naphthalate, and the low refractive index resin is polyester containing spiroglycol and cyclohexanedicarboxylic acid. When the low refractive index resin is a polyester containing spiroglycol and cyclohexanedicarboxylic acid, the difference in in-plane refractive index from polyethylene terephthalate and polyethylene naphthalate increases, making it easier to obtain high reflectance. In addition, since the difference in glass transition temperature from polyethylene terephthalate and polyethylene naphthalate is small and the adhesiveness is excellent, overstretching during molding is less likely to occur, and delamination is less likely to occur.

It is also preferable that the high refractive index resin is polyethylene terephthalate or polyethylene naphthalate, and the low refractive index resin is polyester containing cyclohexanedimethanol. Here, the polyester containing cyclohexanedimethanol means a copolyester or homopolyester copolymerized with cyclohexanedimethanol, or a blended polyester thereof. A polyester containing cyclohexanedimethanol has a small difference in glass transition temperature from polyethylene terephthalate and polyethylene naphthalate, and thus is less likely to be overstretched during molding and less likely to delaminate, which is preferable. In this case, the low refractive index resin is more preferably an ethylene terephthalate polycondensate having a copolymerization amount of cyclohexanedimethanol of 15 mol % or more and 60 mol % or less.

By doing so, while maintaining high reflective performance, changes in optical properties due to heating and aging are particularly small, and delamination between layers is less likely to occur. An ethylene terephthalate polycondensate having a copolymerization amount of cyclohexanedimethanol within the above range adheres very strongly to polyethylene terephthalate. In addition, the cyclohexanedimethanol group has cis and trans isomers as geometric isomers, and chair and boat isomers as conformational isomers. In addition, changes in optical properties due to thermal history are even less, and cracking during film formation is less likely to occur.

In the above resin multilayer film, it is sufficient that there is a portion having a structure in which high refractive index resin layers and low refractive index resin layers are alternately laminated in the thickness direction. That is, it is preferable that the arrangement order in the thickness direction of the high refractive index resin layer and the low refractive index resin layer is not random. is not particularly limited. Further, when the multilayer film of the above resin has a high refractive index resin layer, a low refractive index resin layer, and another resin layer, the order of their arrangement is as follows: A for the high refractive index resin layer; When the resin layer is B and the other resin layers are C, it is more preferable that the layers are laminated in a regular order such as A(BCA) _n , A(BCBA) _n , A(BABCBA) _n . Here, n is the number of repeating units, and for example, when n=3 in A(BCA) _n , it indicates that layers are stacked in the order of ABCABCABCA in the thickness direction.

In addition, the number of laminated layers of the high refractive index resin layer and the low refractive index resin layer is appropriately adjusted as long as the above-described incident angle dependency of reflectance and transmittance can be obtained. Specifically, the high refractive index resin layer and the low refractive index resin layer can be alternately laminated with 30 layers or more, and each layer may be laminated with 200 layers or more. Also, the total number of laminated layers of the high refractive index resin layers and the low refractive index resin layers can be, for example, 600 layers or more. If the number of laminated layers is too small, sufficient reflectance may not be obtained. Moreover, a desired reflectance can be easily obtained by setting the number of laminations within the above range. The upper limit of the total number of layers to be laminated is not particularly limited, but it can be set to, for example, 1500 layers or less in consideration of deterioration in lamination accuracy due to an increase in the size of the device and an excessive number of layers.

Furthermore, the above resin multilayer film preferably has a surface layer containing polyethylene terephthalate or polyethylene naphthalate with a thickness of 3 μm or more on at least one side, and more preferably has the above surface layer on both sides. Further, it is more preferable that the thickness of the surface layer is 5 μm or more. By having the surface layer, the surface of the resin multilayer film can be protected.

Examples of the method for manufacturing the above resin multilayer film include a co-extrusion method. Specifically, the method for producing a laminated film described in JP-A-2008-200861 can be referred to.

In addition, as the multilayer film of the resin, a commercially available laminated film can be used, and specific examples include Picassus (registered trademark) manufactured by Toray Industries, Inc. and ESR manufactured by 3M.

b) Reflective structure The reflective structure has a patterned first reflective film and a patterned second reflective film in this order from the first layer side, and the opening of the first reflective film and the second reflective film The openings are positioned so as not to overlap each other in plan view, and the first reflective film and the second reflective film are spaced apart in the thickness direction.

The reflective structure has two aspects. A first aspect of the reflective structure includes a transparent substrate, a patterned first reflective film arranged on one surface of the transparent substrate, and a patterned second reflective film arranged on the other surface of the transparent substrate. and a reflective film, wherein the opening of the first reflective film and the opening of the second reflective film are positioned so as not to overlap each other in plan view, and the first reflective film and the second reflective film are spaced apart in the thickness direction. There is. A second aspect of the reflective structure includes a transparent base material, a light-transmissive patterned convex portion disposed on one surface of the transparent base material, and a surface of the convex portion facing the transparent base material. A patterned first reflective film arranged on the opposite surface side, and a patterned second reflective film arranged in the opening of the convex portion on one surface of the transparent substrate, wherein the first reflective film and the opening of the second reflective film are positioned so as not to overlap each other in plan view, and the first reflective film and the second reflective film are spaced apart in the thickness direction. Hereinafter, each aspect will be described separately.

(First aspect of reflecting structure)
A first aspect of the reflective structure in this embodiment includes a transparent substrate, a patterned first reflective film arranged on one surface of the transparent substrate, and a pattern arranged on the other surface of the transparent substrate. shaped second reflective film, the opening of the first reflective film and the opening of the second reflective film are positioned so as not to overlap in plan view, and the first reflective film and the second reflective film extend in the thickness direction are placed apart.
In the case of the reflective structure of this aspect, the first layer is arranged on the surface of the reflective structure on the first reflective film side in the second diffusing member.

7A and 7B are a schematic plan view and a cross-sectional view showing an example of the reflecting structure of this embodiment, and FIG. 7A is a view of the reflecting structure from the first reflecting film side. 7(b) is a plan view, and FIG. 7(b) is a sectional view taken along the line AA of FIG. 7(a). As shown in FIGS. 7A and 7B, the reflective structure 20 includes a transparent substrate 21, a patterned first reflective film 22 arranged on one surface of the transparent substrate 21, and a transparent substrate. and a second reflective film 24 disposed on the other surface of the material 21 . The opening 23 of the first reflecting film 22 and the opening 25 of the second reflecting film 24 are positioned so as not to overlap each other in plan view. The first reflective film 22 and the second reflective film 24 are arranged on both sides of the transparent base material 21, respectively, and are spaced apart in the thickness direction. In addition, in FIG. 7A, the opening of the second reflective film is indicated by a broken line. Further, FIG. 7C is a schematic cross-sectional view showing an example of a surface emitting device provided with a diffusing member having a reflecting structure of this aspect.

In such a reflective structure, the patterned first reflective film and the second reflective film are laminated so that the openings of the first reflective film and the openings of the second reflective film do not overlap in plan view. Therefore, when the diffusing member having the reflective structure of this embodiment is used in a surface emitting device, the first reflective film 22 and the At least one of the second reflecting films 24 must be present. Therefore, for example, as shown in FIG. 7B, the surface of the reflective structure 20 on the side of the first reflective film 22, that is, the side on which the first layer (not shown) of the reflective structure 20 (second layer) is arranged The light L11 incident on the surface 13A at a low incident angle can be reflected by the first reflecting film 22 and the second reflecting film 24. As shown in FIG.

In addition, since the opening of the first reflective film and the opening of the second reflective film are positioned so as not to overlap each other in plan view, and the first reflective film and the second reflective film are spaced apart in the thickness direction, Light incident at a high incident angle on the surface of the reflective structure 20 on the side of the first reflective film 22, that is, the surface 13A on the side where the first layer (not shown) of the reflective structure 20 (second layer) is arranged. L12 and L13 can be emitted from the opening 23 of the first reflecting film 22 and the opening 25 of the second reflecting film 24. FIG. As a result, part of the light emitted from the LED element and then emitted from the surface of the diffusion member on the second layer side can be emitted from a position away from the LED element in the in-plane direction instead of directly above the LED element. become able to. Therefore, in-plane uniformity of luminance can be improved.

As the first reflective film and the second reflective film, a general reflective film can be used, and a metal film, a dielectric multilayer film, or the like can be used. As the material of the metal film, metal materials used in general reflective films can be employed, including aluminum, gold, silver, and alloys thereof. In addition, as the dielectric multilayer film, those used in general reflective films can be adopted, and examples thereof include multilayer films of inorganic compounds such as multilayer films in which zirconium oxide and silicon oxide are alternately laminated. . The materials contained in the first reflective film and the second reflective film may be the same or different.

The pitch of the openings of the first reflective film and the second reflective film is sufficient as long as the above-described dependence of reflectance and transmittance on the incident angle can be obtained. It is appropriately set according to the light distribution characteristics, size, pitch and shape, the distance between the LED substrate and the diffusion member, and the like. The pitches of the openings of the first reflective film and the second reflective film may be the same or different.

The pitch of the openings of the first reflective film may be, for example, larger than the size of the LED elements. Specifically, the pitch of the openings of the first reflective film can be 0.1 mm or more and 20 mm or less.

Also, the pitch of the openings of the second reflective film is not particularly limited as long as it can suppress luminance unevenness. is preferably smaller than the pitch of the openings. Specifically, the pitch of the openings of the second reflective film can be 0.1 mm or more and 2 mm or less. By making the pitch of the openings of the second reflective film fine as described above, it is possible to make it difficult to visually recognize the pattern of the portion of the second reflective film and the portion of the openings of the second reflective film. It is possible to emit surface light without

It should be noted that the pitch of the openings of the first reflecting film means the distance P1 between the centers of the openings 23 of the adjacent first reflecting films 22, as shown in FIG. 7(a), for example. Further, the pitch of the openings of the second reflecting film means the distance P2 between the centers of the openings 25 of the adjacent second reflecting films 24 as shown in FIG. 7A, for example.

The sizes of the openings of the first reflective film and the second reflective film are sufficient as long as the above-described dependence of reflectance and transmittance on the incident angle can be obtained. It is appropriately set according to the distance between the LED substrate and the diffusion member. The sizes of the openings of the first reflective film and the second reflective film may be the same or different.

Regarding the size of the opening of the first reflective film, specifically, when the shape of the opening of the first reflective film is rectangular, the length of the opening of the first reflective film is 0.1 mm or more. It can be 5 mm or less.

Also, the size of the opening of the second reflecting film is not particularly limited as long as it can suppress unevenness in luminance. It is preferably smaller than the size of the opening of the reflective film. Specifically, when the shape of the opening of the second reflective film is rectangular, the length of the opening of the second reflective film can be 0.05 mm or more and 2 mm or less. By making the size of the opening of the second reflective film fine as described above, it is possible to make it difficult to visually recognize the pattern of the portion of the second reflective film and the portion of the opening of the second reflective film. It is possible to emit surface light without

For example, when the shape of the opening of the first reflective film is rectangular, the size of the opening of the first reflective film is the size of the opening 23 of the first reflective film 22 as shown in FIG. is the length x1 of Further, the size of the opening of the second reflective film means the length x2 of the opening 25 of the second reflective film 24 as shown in FIG. 7A, for example.

The shape of the openings of the first reflective film and the second reflective film can be any shape such as a rectangular shape or a circular shape. The thicknesses of the first reflective film and the second reflective film are appropriately adjusted as long as the above-described dependence of reflectance and transmittance on the incident angle can be obtained. Specifically, the thicknesses of the first reflective film and the second reflective film can be 0.05 μm or more and 100 μm or less.

The first reflective film and the second reflective film may be formed on the surface of the transparent substrate, or may be sheet-like reflective films. A method for forming the first reflective film and the second reflective film is not particularly limited as long as it is a method capable of forming a patterned reflective film on the surface of the transparent base material, and examples thereof include a sputtering method and a vacuum deposition method. Further, when the first reflective film and the second reflective film are sheet-like reflective films, examples of the method of forming the opening include a method of forming a plurality of through holes by punching or the like. In this case, as a method of laminating the transparent substrate and the sheet-like reflective film, for example, a method of bonding the sheet-like reflective film to the transparent substrate via an adhesive layer or an adhesive layer can be used.

The transparent base material in the reflective structure of this aspect is a member that supports the first reflective film and the second reflective film, etc., and the first reflective film and the second reflective film are spaced apart in the thickness direction. It is a member for

The transparent base material has optical transparency. As for the light transmittance of the transparent substrate, the total light transmittance of the transparent substrate is preferably, for example, 80% or more, and more preferably 90% or more. The total light transmittance of the transparent substrate can be measured by a method conforming to JIS K7361-1:1997.

The material constituting the transparent substrate may be any material having the above-mentioned total light transmittance, and resins such as polyethylene terephthalate, polycarbonate, acrylic, cycloolefin, polyester, polystyrene, acrylic styrene, quartz glass, pyrex ( (registered trademark) and synthetic quartz glass.

As for the thickness of the transparent substrate, for example, as shown in FIG. ) is arranged, the light L12 incident at a high angle of incidence can be emitted from the opening 23 of the first reflecting film 22 and the opening 25 of the second reflecting film 24. is preferably set according to the pitch and size of the openings of the first and second reflective films, the thickness of the first and second reflective films, and the like. Specifically, the thickness of the transparent substrate can be 0.05 mm or more and 2 mm or less, preferably 0.1 mm or more and 0.5 mm or less.

(Second aspect of reflecting structure)
A second aspect of the reflective structure includes a transparent substrate, a patterned convex portion having light transmittance disposed on one surface of the transparent substrate, and a convex portion opposite to the transparent substrate side of the convex portion. It has a patterned first reflective film arranged on the surface side and a patterned second reflective film arranged in the opening of the convex portion on one surface of the transparent substrate, wherein the opening of the first reflective film and the opening of the second reflective film are positioned so as not to overlap each other in plan view, and the first reflective film and the second reflective film are spaced apart in the thickness direction. In the case of the reflective structure of this aspect, the first layer is arranged on the surface of the reflective structure on the first reflective film side in the second diffusing member.

8A and 8B are a schematic plan view and a cross-sectional view showing an example of a second aspect of the reflecting structure in this embodiment, and FIG. 8A shows the first reflecting film side of the reflecting structure. 8(b) is a cross-sectional view taken along the line AA of FIG. 8(a). As shown in FIGS. 8A and 8B, the reflective structure 20 includes a transparent substrate 21 and a patterned convex portion 26 arranged on one surface of the transparent substrate 21 and having light transmittance. , a patterned first reflective film 22 arranged on the surface opposite to the surface of the convex portion 26 facing the transparent substrate 21, and and a patterned second reflective film 24 . The opening 23 of the first reflecting film 22 and the opening 25 of the second reflecting film 24 are positioned so as not to overlap each other in plan view. In addition, the first reflecting film 22 and the second reflecting film 24 are separated by the convex portion 26 and are spaced apart in the thickness direction.

In such a reflective structure, the patterned first reflective film and the second reflective film are laminated so that the openings of the first reflective film and the openings of the second reflective film do not overlap in plan view. Therefore, a surface emitting device (in particular, an LED backlight) using a diffusion member having a reflecting structure according to this embodiment has at least one of the first reflecting film and the second reflecting film directly above the LED element. One or the other must exist. Therefore, as in the first aspect of the reflecting structure, for example, as shown in FIG. The light L11 incident on the surface 13A on which the first layer (not shown) is arranged at a low incident angle can be reflected by the first reflecting film 22 and the second reflecting film 24 .

In addition, since the opening of the first reflective film and the opening of the second reflective film are positioned so as not to overlap each other in plan view, and the first reflective film and the second reflective film are spaced apart in the thickness direction, Light incident at a high incident angle on the surface of the reflective structure 20 on the side of the first reflective film 22, that is, the surface 13A on the side where the first layer (not shown) of the reflective structure 20 (second layer) is arranged. L12 can be emitted from the side surface of the convex portion 26 and the opening 25 of the second reflective film 24 . As a result, part of the light emitted from the LED element and then emitted from the surface of the diffusion member on the second layer side can be emitted from a position away from the LED element in the in-plane direction instead of directly above the LED element. become able to. Therefore, in-plane uniformity of luminance can be improved. Further, in this aspect, since the projections are provided, self-alignment of the openings of the first reflective film and the second reflective film is possible, and the manufacturing cost can be reduced.

The materials of the first reflective film and the second reflective film, the pitch of the openings of the first reflective film and the second reflective film, the size of the openings of the first reflective film and the second reflective film, the The shape of the opening of the second reflective film, the thickness of the first reflective film and the second reflective film, the method of forming the first reflective film and the second reflective film, and the like can be the same as in the first aspect. .
Also, the transparent substrate may be the same as in the first aspect.

The convex portion in the reflective structure of this aspect is a member for arranging the first reflective film and the second reflective film apart from each other in the thickness direction. The convex portion has optical transparency. As for the light transmittance of the projections, the total light transmittance of the projections is preferably, for example, 80% or more, and more preferably 90% or more. Incidentally, the total light transmittance of the convex portion can be measured by a method conforming to JIS K7361-1:1997.

Any material that can form patterned protrusions and has the above-described total light transmittance can be used as a material for forming the protrusions, and examples thereof include thermosetting resins and electron beam curable resins.

As for the height of the projection, for example, as shown in FIG. ) is arranged, the light L12 incident at a high angle of incidence can be emitted from the side surface of the convex portion 26 and the opening 25 of the second reflecting film 24. is preferably set according to the pitch and size of the openings of the first reflective film and the second reflective film, the thickness of the first reflective film and the second reflective film, and the like. Specifically, the height of the convex portion can be 0.05 mm or more and 2 mm or less, preferably 0.1 mm or more and 0.5 mm or less.

The pitch, size and planar view shape of the projections can be the same as the pitch, size and shape of the openings of the second reflective film. The surface of the projection may be, for example, a smooth surface as shown in FIG. 8(b) or a rough surface as shown in FIG. 9(a). When the surface of the convex portion is rough, the convex portion can be provided with light diffusing properties.

Also, the shape of the surface of the convex portion may be flat as shown in FIG. 8(b), or curved as shown in FIG. 9(b). When the convex portion has a curved surface, the convex portion can be provided with light diffusing properties.

The method of forming the convex portions is not particularly limited as long as it is a method capable of forming pattern-like convex portions, and examples thereof include a printing method and resin molding using a mold.

c) Reflective Diffraction Grating When the second layer is a reflective diffraction grating, the reflective diffraction grating is not particularly limited as long as it has the above-described incident angle dependency of reflectance and transmittance.

The pitch and the like of the reflective diffraction grating are adjusted as appropriate as long as the above-described incident angle dependency of reflectance and transmittance can be obtained. Specifically, when the wavelengths emitted by the LED elements are monochromatic, such as red, green, and blue, it is possible to effectively reflect the light from the LED elements by setting the pitch according to each wavelength. is.

The material constituting the reflective diffraction grating may be any material that provides a reflective diffraction grating having the above-described incident angle dependence of reflectance and transmittance. can be adopted. Also, the method of forming the reflective diffraction grating can be the same as the method of forming a general reflective diffraction grating.

4.3 Third Diffusing Member The third diffusing member is a resin plate containing a light-transmitting resin such as polystyrene (PS) or polycarbonate, which has many voids inside or has an uneven surface. and those generally used in the field of display devices can be used.

5. Wavelength Conversion Member In the surface emitting device of this embodiment, for example, the wavelength conversion member may be arranged on the side of the diffusion member opposite to the LED substrate side, and the wavelength conversion member may be arranged on the LED substrate side of the diffusion member. may be placed.

A wavelength conversion member is a member containing a phosphor that absorbs light emitted from an LED element and emits excitation light. The wavelength conversion member has a function of generating white light by being combined with the LED substrate.

A wavelength conversion member usually has at least a wavelength conversion layer containing a phosphor and a resin. The wavelength conversion member may be, for example, a single wavelength conversion layer, or a laminate having a wavelength conversion layer on one side of a transparent substrate. Among them, the single wavelength conversion layer is preferable from the point of thickness reduction. More preferably, a sheet-like wavelength conversion member is used.

The phosphor can be appropriately selected according to the color of light emitted from the LED element, and blue phosphor, green phosphor, red phosphor, yellow phosphor, and the like can be mentioned. For example, when the LED element is a blue LED element, the phosphor may be a green phosphor, a red phosphor, or a yellow phosphor. Further, for example, when the LED element is an ultraviolet LED element, a red phosphor, a green phosphor, and a blue phosphor can be used as phosphors.

As the phosphor, for example, the phosphor used for the wavelength conversion member of the LED backlight can be adopted. Quantum dots can also be used as phosphors. The content of the phosphor in the wavelength conversion member layer is not particularly limited as long as it can generate the desired white light, and is the same as the content of the phosphor in the wavelength conversion member of a general LED backlight. can be

Also, the resin contained in the wavelength conversion member is not particularly limited as long as it can disperse the phosphor. As the resin, the same resins as those used for wavelength conversion members of general LED backlights can be used, and examples thereof include thermosetting resins such as silicone-based resins and epoxy-based resins.

The thickness of the wavelength conversion member is not particularly limited as long as it can generate desired white light when used in a surface emitting device.

6. Other Optical Members In the surface emitting device of the present embodiment, for example, an optical member may be further arranged on the side of the diffusion member opposite to the side facing the LED substrate. Examples of optical members include a prism sheet and a reflective polarizing sheet.

(1) Prism Sheet The prism sheet in this embodiment has the function of concentrating the incident light and intensively improving the luminance in the front direction. The prism sheet has, for example, a prism pattern containing an acrylic resin arranged on one side of a transparent resin substrate. As the prism sheet, for example, brightness enhancement film BEF series manufactured by 3M can be used.

(2) Reflective polarizing sheet The reflective polarizing sheet in this embodiment transmits only the first linearly polarized component (e.g., P-polarized light) and the second linearly polarized component orthogonal to the first linearly polarized component. It has the function of reflecting (for example, S-polarized light) without absorbing it. The second linearly polarized component reflected by the reflective polarizing sheet is reflected again, and in a depolarized state (including both the first linearly polarized component and the second linearly polarized component), Incident on the reflective polarizing sheet. Therefore, the reflective polarizing sheet transmits the first linearly polarized light component of the re-entering light, and reflects the second linearly polarized light component orthogonal to the first linearly polarized light component.

By repeating the above process, about 70% or more and 80% or less of the light emitted from the second layer is emitted as the first linearly polarized light component. Therefore, when the surface emitting device of this embodiment is used in a display device, the polarization direction of the first linearly polarized light component (transmission axis component) of the reflective polarizing sheet and the transmission axis direction of the polarizing plate of the display panel are matched. As a result, all the light emitted from the surface emitting device can be used for image formation on the display panel. Therefore, even if the light energy input from the LED element is the same, it is possible to form a brighter image than in the case where the reflective polarizing sheet is not arranged.

Examples of reflective polarizing sheets include the DBEF series of brightness enhancement films manufactured by 3M. Also, as the reflective polarizing sheet, for example, a high brightness polarizing sheet WRPS and a wire grid polarizer manufactured by Shinwha Intertek can be used.

7. Use The use of the surface emitting device in this embodiment is not particularly limited, but it can be suitably used for a display device. Moreover, it can be used for a lighting device or the like.

II. Second Embodiment Next, a second embodiment of the surface emitting device of this embodiment will be described.
FIG. 10 is a schematic cross-sectional view showing an example of the surface emitting device of this embodiment. As illustrated in FIG. 10 , the surface emitting device 1 of this embodiment includes a support substrate 2 , an LED substrate 4 having LED elements 3 arranged on one side of the support substrate 2 , and LEDs of the LED substrate 4 . A sealing member 5 arranged on the surface side of the element 3 side and sealing the LED element 3, a diffusion member 6 arranged on the surface side of the sealing member 5 opposite to the LED substrate 4 side, and the LED substrate 4 and an anti-warp layer 7 disposed on the surface opposite to the sealing member 5 . The sealing member 5 in this embodiment has a haze value of 4% or more and a thickness greater than that of the LED element 3, and the linear expansion coefficient of the material constituting the warp prevention layer 7 It is characterized by having a coefficient of linear expansion equal to or greater than that of the material forming 5.

In the surface emitting device of this embodiment, when a means such as thermocompression bonding is used to join the sealing member and the LED substrate, a line between the LED substrate and the sealing member is formed during subsequent cooling. Warpage may occur due to differences in expansion coefficients.
Further, when the surface emitting device is used at extremely high or low temperatures, warping may occur due to the difference in coefficient of linear expansion between the LED substrate and the sealing member.

This embodiment, like the first embodiment, was made to solve such a problem, and the warpage prevention layer is arranged on the surface of the LED substrate opposite to the sealing member. However, by making the coefficient of linear expansion of the material constituting the warp prevention layer equal to or greater than the coefficient of linear expansion of the material constituting the sealing member, the above problem of warping is solved. .

The surface emitting device of this embodiment will be described below. In addition, since this embodiment is the same as the first embodiment except that the arrangement position of the warp prevention layer and the material constituting the warp prevention layer are different from the first embodiment, warp Description of the configuration other than the prevention layer is omitted.

1. Warpage Prevention Layer The warpage prevention layer in this embodiment is a layer arranged on the surface of the LED substrate opposite to the sealing member.
In this embodiment, the coefficient of linear expansion of the material forming the anti-warp layer is equal to or greater than the coefficient of linear expansion of the material forming the sealing member. The reason why warping can be prevented by making the coefficient of linear expansion of the material forming the warp prevention layer equal to or greater than that of the material forming the sealing member is as follows.

That is, when manufacturing a surface emitting device, there is a step of thermally compressing the sealing member and the LED substrate, but the sealing member shrinks more than the LED substrate during cooling after the thermal compression bonding. At this time, since a warp prevention layer having a coefficient of linear expansion equal to or larger than that of the sealing member is disposed on the surface of the LED substrate opposite to the sealing member, warping is prevented with respect to the contraction of the sealing member. Since the prevention layer also shrinks, it is possible to reduce the degree of warping of the LED substrate, and as a result, it is possible to suppress the occurrence of warping.

a) Coefficient of linear expansion In this embodiment, the greater the difference between the coefficient of linear expansion of the material forming the anti-warp layer and the coefficient of linear expansion of the material forming the sealing member, the better. Considering the material used for the stop member, it is somewhat limited. Therefore, the difference in the coefficient of linear expansion is usually 400 × 10 ^-6 / ° C. or less, and may be equivalent

In this embodiment, "equivalent" means that the coefficient of linear expansion of the material constituting the sealing member is in the range of 0.8 or more and 1.2 or less, particularly 0.95 or more and 1.0 or less. Refers to the case within the range.

The linear expansion coefficient of the material constituting such a warp prevention layer is usually in the range of 300×10 ⁻⁶ /° C. or more and 500×10 ⁻⁶ /° C. or less, particularly 350×10 ⁻⁶ /° C. or more and 450×10 Those within the range of ^-6 /°C or less are used.
As a method for measuring the coefficient of linear expansion in this embodiment, the same method as described in the first embodiment is used.

b) Thickness The thickness of the anti-warp layer in this embodiment is preferably 25% or more, more preferably 35% or more, more preferably 45% or more of the thickness of the sealing member. Note that the upper limit is set to 50% or less from the concept of compactness of the apparatus. If it is within the above range, it is possible to obtain the effect of preventing warpage, and it does not hinder the compactness of the device.

c) Elastic modulus The elastic modulus of the anti-warp layer used in this embodiment is preferably equal to or higher than the elastic modulus of the sealing member.
Specifically, when the elastic modulus of the sealing member is 1, it is preferably 0.8 or more, and particularly preferably 0.9 or more. In addition, it becomes 2.5 or less normally.

In addition, the actual value is preferably 35 MPa or more, particularly preferably 40 MPa or more, and most preferably 85 MPa or more. This is because if the elastic modulus is lower than the above range, the effect of preventing warpage is reduced. It should be noted that considering the materials that are normally used, it is 300 MPa or less.

d) Material The material constituting the anti-warp layer used in this embodiment is not particularly limited as long as it has the above characteristics, but among them, the same material as that used as the sealing member can be used. .
A preferable material is an olefin resin. Among olefin resins, polyethylene resins, polypropylene resins, and ionomer resins are preferable.

(2) Others It is preferable that the anti-warp layer in this embodiment is in close contact with the LED substrate. This is because the warp prevention effect can be further improved.
Since the specific degree of adhesion and the like are the same as those of the first embodiment, description thereof is omitted here.
Examples of the method of adhering the anti-warp layer and the LED substrate include a method of disposing an adhesive layer between the two and adhering them together, and a method of thermocompression bonding to melt and adhere the anti-warp layer. .

III. Third Embodiment The surface light-emitting device of this embodiment uses an anti-foaming layer in place of the anti-warp layer in the first embodiment, and the anti-foaming layer has an elastic modulus of 500 MPa or more. There are two aspects, one aspect and the aspect in which the foaming prevention layer has a melting point of 140° C. or higher.

In conventional surface emitting devices, for example, when the surface emitting device is used at extremely high temperatures for a long time, there is also the problem that air bubbles are generated between the LED substrate and the sealing member. This is caused by the gas generated from the LED substrate by heating, or when a reflective layer or the like is provided on the LED substrate, air existing between the LED substrate and the reflective layer or the like due to air entrainment or the like may cause the interface It occurs due to causes such as oozing along.

In the LED element sealed with the sealing member, the light emitting surface of the sealing member and the LED element are directly bonded, and the refractive index difference at the interface is small. Improve efficiency. However, if such bubbles exist, the light extraction efficiency cannot be improved as described above, and as a result, the luminous efficiency of the surface light emitting device is lowered.

In this embodiment, by providing the anti-foaming layer having the properties described above, it is possible to suppress the deformation of the surface of the sealing member, which is expected to occur during foaming, such that the surface shape becomes a convex portion.
As a result, for example, even if gas is generated from the LED substrate, the presence of the anti-foaming layer applies pressure to the sealing member, making it possible to prevent the generated gas from forming bubbles. .

The elastic modulus of the anti-foaming layer used in this embodiment may be 500 MPa or higher, preferably 1000 MPa or higher, and more preferably 4000 MPa or higher.

This is because if the elastic modulus is lower than the above range, the effect of suppressing bubble generation is reduced.
It should be noted that the pressure is 5500 MPa or less in consideration of commonly used materials.

The melting point of the anti-foaming layer in this embodiment may be 140°C or higher, but preferably 260°C or higher. The upper limit is 350.degree.

In this embodiment, it is more preferable to use a foam-preventing layer having the above-described elastic modulus and the above-described melting point.
The methods for measuring the elastic modulus and the melting point are the same as those described in the first embodiment.

Unlike the anti-warp layer, the anti-foam layer used in this embodiment does not necessarily have a coefficient of linear expansion within a predetermined range. However, since the anti-foaming layer has a coefficient of linear expansion similar to that of the anti-warping layer in the first embodiment, the same anti-warping effect as in the first embodiment can be obtained, so it is preferable. can do.

Other points of the surface light-emitting device of this embodiment are the same as those of the surface light-emitting device of the first embodiment except that the anti-foaming layer is used instead of the anti-warp layer, so description thereof will be omitted here.

B. Display Device The present disclosure provides a display device including a display panel and the above-described surface emitting device arranged on the back surface of the display panel.

FIG. 11 is a schematic diagram showing an example of the display device of the present disclosure. As illustrated in FIG. 11 , the display device 100 includes a display panel 31 and the surface emitting device 1 according to the present disclosure arranged behind the display panel 31 .

According to the present disclosure, by having the above-described surface light emitting device, it is possible to improve the in-plane uniformity of luminance and achieve a reduction in thickness. Therefore, a high-quality display device can be obtained.

1. Surface Light-Emitting Device The surface light-emitting device in the present disclosure is the same as that described in the section “A. Surface Light-Emitting Device” above.

2. Display Panel The display panel in the present disclosure is not particularly limited, and examples thereof include a liquid crystal panel.

C. Method for Manufacturing Surface Light Emitting Device The present disclosure provides a method for manufacturing the surface light emitting device of the first embodiment. The present disclosure can be divided into two embodiments.

I. First Embodiment A method for manufacturing a surface light-emitting device of this embodiment is the manufacturing method described in the first embodiment of the surface light-emitting device, wherein the anti-warp layer, the sealing member, and the LED element are The method is characterized by comprising a step of preparing a laminate in which the LED substrates arranged so as to face the sealing member side are arranged in this order, and bonding the laminate by thermocompression.
In this embodiment, first, a laminate is prepared in which the LED substrate, the sealing member, and the anti-warp layer are arranged in this order.

Here, since the LED substrate, the sealing member, and the anti-warp layer are the same as those described in the first embodiment of the surface emitting device, description thereof will be omitted here.
Next, a step of thermally compressing the laminate is performed.

The thermocompression bonding method in the present embodiment is not particularly limited as long as it is a method capable of thermocompression bonding, but a vacuum lamination method, a vacuum packing method, a heat lamination method, or the like can be used.

In this embodiment, a surface light-emitting device can be manufactured by arranging a diffusion member on the side of the anti-warping layer of the laminated body that is press-bonded, and adhering it with an adhesive or the like.

II. Second Embodiment A method for manufacturing a surface light-emitting device of this embodiment is the manufacturing method described in the first embodiment of the surface light-emitting device. a step of thermocompression bonding one laminated body; 2. The step of thermally compressing the laminated body.

In the present embodiment, first, a first laminate in which the anti-warp layer and the sealing member are laminated is prepared. Next, the first laminate is thermocompression bonded by the same method as in the first embodiment.

Next, a second laminate in which the LED substrate is arranged on the sealing member side surface of the thermocompressed first laminate is thermocompressed by the same method as in the first embodiment.
In this embodiment, a surface light-emitting device can be manufactured by arranging a diffusion member on the anti-warp layer side of the pressed second laminated body and adhering it with an adhesive or the like.

D. Surface Emitting Device Sealing Member Sheet The surface emitting device sealing member sheet of the present disclosure has the following two aspects.

1. First Aspect A sealing member sheet for a surface light-emitting device of this aspect comprises a sealing member for sealing an LED element and an anti-warping layer disposed on one side of the sealing member. A surface light emitting device sealing member sheet used in a surface light emitting device, wherein the linear expansion coefficient of the material constituting the warp prevention layer is −15×10 ⁻⁶ /° C. or more and 10×10 ⁻⁶ / °C or less.

The surface emitting device includes a support substrate, an LED substrate having the LED elements arranged on one side of the support substrate, the sealing member arranged on the LED element side of the LED substrate, and the warp. A blocking layer and a diffusion blocking member are laminated in this order.

The anti-warping layer used in this aspect is the same as that described in the first aspect of the surface emitting device. Also, the LED substrate, the sealing member, and the antireflection member are the same as those described in the surface light emitting device, and therefore descriptions thereof are omitted here.

2. Second Aspect In the surface emitting device sealing member sheet of this aspect, a sealing member for sealing an LED element and an anti-foaming layer disposed on one side of the sealing member are laminated. A sealing member sheet for a surface light emitting device used in a surface light emitting device, wherein the elastic modulus of the material constituting the antifoaming layer is 500 MPa or more, and the melting point of the material constituting the antifoaming layer is 140° C. or higher.

The surface emitting device includes: a support substrate; an LED substrate having the LED elements arranged on one side of the support substrate; the sealing member arranged on the LED element side of the LED substrate; A blocking layer and a diffusion blocking member are laminated in this order.

The anti-foaming layer used in this embodiment is the same as that described in the third embodiment of the surface light-emitting device. Also, the LED substrate, the sealing member, and the antireflection member are the same as those described in the surface light emitting device, and therefore descriptions thereof are omitted here.

It should be noted that the present disclosure is not limited to the above embodiments. The above embodiment is an example, and any device that has substantially the same configuration as the technical idea described in the claims of the present disclosure and achieves the same effect is the present invention. It is included in the technical scope of the disclosure.

Experimental examples regarding sealing members are shown below, and then examples and comparative examples of the present disclosure are shown to describe the present disclosure in more detail.

A. Experimental example (Experimental example 1)
As shown in FIG. 11, a surface emitting device 1 having a support substrate 2, a light emitting diode substrate 4 having a light emitting diode element 3, a sealing member A (450 μm thick) 5, a diffusion member A 6, and a wavelength converting member 9 is manufactured. bottom. Table 1 shows the haze value, layer structure, density and transmittance at a wavelength of 450 nm of the sealing member A. Table 2 shows the evaluation results of luminance unevenness evaluated by the following method.

The members used are as follows.
- Light-emitting diode substrate LED chips B0815ACQ0 (chip size 0.2 mm x 0.4 mm, manufactured by GENERITES) were squarely arranged on a support substrate (reflectance 95%) at a pitch of 6 mm.
・Diffusion member A (diffusion plate)
55K3 (manufactured by Entire)
・Wavelength conversion member (QD)
QF-6000 (manufactured by Showa Denko Materials)

The thickness of the sealing member and the optical properties shown in Table 1 were obtained by sandwiching the sealing member sheet between ETFE films (thickness: 100 μm) and performing heat treatment by vacuum lamination. is the value The optical properties were measured by peeling off the ETFE film and measuring only the sealing member sample. Vacuum lamination conditions were as follows.

(Vacuum lamination conditions)
(a) Evacuation: 5.0 minutes (b) Pressure: changed from 0 kPa to 100 kPa in 5 seconds (c) Pressure retention: (100 kPa): 7 minutes (d) Temperature: 150 ° C.

(Experimental example 2)
The occurrence of luminance unevenness was evaluated in the same manner as in Experimental Example 1, except that the diffusion member B described below was used instead of the diffusion member A. Table 2 shows the results.
・Diffusion member B
A second diffusion member having a prism structure in which a prism surface is formed on the light emitting diode element side as a first layer and a dielectric multilayer film as a second layer

(Experimental examples 3 and 4)
The occurrence of luminance unevenness was evaluated in the same manner as in Experimental Examples 1 and 2, except that the sealing member B (thickness: 450 μm) shown in Table 1 was used instead of the sealing member A.

(Experimental Examples 5 and 6)
The occurrence of luminance unevenness was evaluated in the same manner as in Experimental Examples 1 and 2, except that the sealing member D (thickness: 450 μm) shown in Table 1 was used instead of the sealing member A.

(Comparative Experimental Examples 1 and 2)
The occurrence of luminance unevenness was evaluated in the same manner as in Experimental Examples 1 and 2, except that instead of the sealing member A, a pin was provided between the diffusion member and the light emitting diode substrate. Table 2 shows the results. At this time, the distance between the light emitting diode element and the diffusion member was 500 μm.

(Comparative Experimental Examples 3 and 4)
The occurrence of luminance unevenness was evaluated in the same manner as in Experimental Examples 1 and 2, except that instead of the sealing member A, a cured Si material (450 μm thick) using a highly transparent potting type liquid silicone composition was provided. Table 2 shows the results.

(Comparative Experimental Examples 5 and 6)
The occurrence of luminance unevenness was evaluated in the same manner as in Experimental Examples 1 and 2, except that the sealing member C (thickness: 450 μm) shown in Table 1 was used instead of the sealing member A. Table 2 shows the results.

[Brightness unevenness evaluation method]
For the obtained surface light-emitting device, the luminance during LED emission was measured using a two-dimensional color luminance meter CA2000, and luminance unevenness was evaluated. The index of luminance unevenness was judged as follows from the numerical value of uniformity.

[Evaluation criteria]
Uniformity = minimum front luminance/maximum front luminance A: Uniformity greater than 0.9 B: Uniformity 0.8 or more and 0.9 or less C: Uniformity less than 0.8

The surface emitting devices (Experimental Examples 1 to 6) according to the present disclosure were able to suppress the occurrence of luminance unevenness. In Comparative Experimental Examples 3 and 4 using the cured product, and in Comparative Experimental Examples 5 and 6 using the sealing member C having a low haze value, the occurrence of luminance unevenness could not be suppressed.

B. Examples of First and Second Embodiments Examples of the surface emitting devices of the first and second embodiments are shown below.

[Example B-1]
(Formation of laminate of sealing member and anti-warp layer)
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) are mixed with 100 parts by mass of the following base resin 1, and the PET film integrated sealing is performed. A sealing member composition for molding a sealing member material was obtained.

・Base resin 1
A metallocene-based 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): Masterbatch with 0.6 parts by mass added

・Additive resin 2 (silane-modified polyethylene resin)
5 parts by mass of ^{vinyltrimethoxysilane} and a radical generator (reaction catalyst ) is mixed with 0.15 parts by mass of dicumyl peroxide, melted at 200° C., and kneaded to obtain a silane-modified polyethylene resin. The added resin 2 has a density of 0.901 g/cm ³ and an MFR of 1.0 g/10 minutes.

Next, a biaxially stretched polyethylene terephthalate film (optical grade) with a thickness of 50 μm is used as the warp prevention layer, and this is integrated with the film in which the above-described sealing member composition is melt extruded by pressure bonding, An anti-warp layer laminate was formed by stacking an anti-warp layer and a sealing member having a thickness of 300 μm.

Then, using a vacuum laminator, the PCB substrate and the anti-warp layer laminate were laminated. The PCB board is white paint, copper, and glass epoxy laminated in that order.

From the hot plate side of the vacuum laminator, hot plate, Teflon (registered trademark) coated glass sheet 0.3 mm, glass (thickness 3 mm), release PET (release surface: upper), glass epoxy surface on the release PET side The above PCB substrate, the warp prevention layer laminate with the sealing member on the PCB substrate side, release PET (release surface: bottom), glass (thickness 3 mm), and Teflon (registered trademark) coated glass sheet Lamination processing was performed with a vacuum heating laminator under the processing conditions of 130° C. and 8 minutes as the conditions of the vacuum laminator in a state in which a thickness of 0.3 mm was laminated. After completion of lamination, the whole glass sheet was moved to a cooling shelf and cooled for about 10 to 15 minutes to obtain a sealing member laminate of the first embodiment. Various evaluations were performed regarding the sealing member laminate as a surface emitting device.

[Example B-2]
A sealing member laminate of the first embodiment was obtained in the same manner as in Example B-1, except that the thickness of the anti-warp layer was 100 μm.

[Example B-3]
A sealing member composition similar to that of Example B-1 and a PCB substrate similar to that of Example B-1 were used.
First, on the glass epoxy surface of the PCB member, a film obtained by melt-extrusion of the composition for a sealing member was pressed to a thickness of 160 μm as a warp prevention layer, and then, on the white painted surface of the PCB member. A film obtained by melt-extrusion of the composition for a sealing member was pressure-bonded as a sealing member so as to have a film thickness of 240 μm to obtain a sealing member laminate of the second embodiment.

[Example B-4]
A sealing member laminate of the second embodiment was obtained in the same manner as in Example B-3, except that the thickness of the sealing member was 320 μm and the thickness of the anti-warp layer was 80 μm.

[Example B-5]
A sealing member laminate of the first embodiment was obtained in the same manner as in Example B-2, except that a biaxially stretched polyethylene terephthalate film (general-purpose grade) different from that in Example 2 was used as the warp prevention layer. .
[Example B-6]
A sealing member laminate was obtained in the same manner as in Example B-1, except that the sealing member laminate was produced by bonding the sealing member and the warp prevention layer with a dry laminate adhesive.
A polycarbonate urethane-based adhesive was used as the main agent of the dry laminating adhesive, and an isocyanate-based curing agent was used as the curing agent material. Also, the ratio of the main agent and the curing agent was set at 10:1, and the main agent and the curing agent were dissolved in a solvent to make each 50% by mass (ethyl acetate solution).

Lamination of sealing member for backlight by bonding and laminating PET and sheet-shaped sealing member using a laminator capable of dry lamination using a two-liquid type adhesive consisting of the above main agent and curing agent manufactured the body. As the PET film, a biaxially oriented polyethylene terephthalate film (optical grade) is used. Gravure coating was performed so as to have a thickness of 2 to 15 g/m 2 (2 to 15 μm in film thickness after curing), and the solvent was volatilized and dried in a drying hood at about 70 to 90° C. to prepare an adhesive surface. After that, the sealing member was unwound from the second paper feed, laminated by nip rolls, laminated in a PET/adhesive/sealing member state, and then wound up by a winding unit to produce a sealing member laminate. After the laminated roll was produced, it was cured by aging treatment at 30 to 50° C. for about 70 to 200 hours.

[Comparative Example B-1]
A sealing member laminate was obtained in the same manner as in Example B-1, except that the anti-warp layer laminate was used as a sealing member having a film thickness of 400 μm.

[Comparative Example B-2]
A sealing member laminate of the first embodiment was obtained in the same manner as in Example B-1, except that a polycarbonate film (standard grade) having a thickness of 100 μm was used as the anti-warp layer.

[Evaluation method]
(linear expansion coefficient)
For a sheet cut to 5 mm×20 mm, the dimensional change was measured according to JISK7197 when the temperature was raised and then lowered to room temperature. The coefficient of linear expansion here is a positive value during contraction and a negative value during expansion. The measurement was performed using the following measurement apparatus and measurement conditions.
・Measuring device: Thermomechanical device manufactured by Seiko Instruments (TMA/SS-6000)
・Constant load tensile mode: 0.1 mN
・Measurement temperature range: -50°C to 160°C
・Linear expansion coefficient calculation temperature range: 25°C to 100°C

(elastic modulus)
Tensile measurements were performed as described below.
(Measuring method)
・Measuring device: Universal material testing machine 5565 manufactured by Instron
・Load cell: 1kN
・Sample width: 10 mm
・Distance between chucks: 50mm
・Speed: 300mm/min

(melting point)
It was measured according to JIS K 7121 using a differential scanning calorimeter (DSC-60 Plus, manufactured by Shimadzu Corporation).

(Total light transmittance)
Measured by a method conforming to JIS K7361-1:1997.

(Haze value)
Measured according to JIS K7136 using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory).

(Warpage amount)
Each sealing member laminate immediately after vacuum lamination is left to stand on a horizontal surface in a normal temperature environment for 24 hours or more. After that, the height from the horizontal plane of the corner to the bottom side of the substrate was measured with a steel straightedge in accordance with JIS B 7514.

(Foam test)
Immediately after vacuum lamination, each sealing member laminate was placed in a constant temperature bath at 100° C. for 1000 hours in accordance with JIS C 60068-2-2, and the presence or absence of foaming was observed.

(Brightness unevenness)
A diffusion member was placed on the sealing member side surface of each of the sealing member laminates obtained in Examples B-1 to B-6 and Comparative Examples B-1 to B-2. was obtained. The measurement method and evaluation criteria for luminance unevenness are the same as those shown in the above experimental example. As the diffusion member, the same diffusion member B used in Experimental Example 2 was used.

The results are shown in Table 3.

C. Example of the Third Embodiment Next, an example of the surface emitting device of the third embodiment will be shown.

[Example C-1]
A sealing member laminate of the third embodiment was obtained in the same manner as in Example B-1 above, except that a 35 μm thick biaxially stretched polyethylene terephthalate film (optical grade) was used as the antifoaming layer. Various evaluations were performed regarding the sealing member laminate as a surface emitting device.

[Example C-2]
A sealing member laminate was obtained in the same manner as in Example B-1 above, except that the anti-warp layer was used as the anti-foaming layer.

[Example C-3]
A sealing member laminate was obtained in the same manner as in Example B-2 above, except that the anti-warp layer was used as the anti-foaming layer.

[Example C-4]
A sealing member laminate was obtained in the same manner as in Example B-1 above, except that random polypropylene having a thickness of 100 μm was used as the anti-foaming layer.

[Example C-5]
A sealing member laminate was obtained in the same manner as in Comparative Example B-2 above, except that the anti-warp layer was used as the anti-foaming layer.

[Comparative Example C-1]
A sealing member laminate was obtained in the same manner as in Comparative Example B-1.

[Evaluation method]
Elastic modulus, melting point, and foaming test were performed in the same manner as in "B. Examples of first and second embodiments" above.
The results are shown in Table 4.

That is, the present disclosure can provide the following inventions.
[1] A surface light-emitting device for use in a surface light-emitting device, in which a sealing member for sealing a light-emitting diode element and a warp prevention layer disposed on one side of the sealing member are laminated. A surface light emitting device sealing member sheet, wherein the linear expansion coefficient of the material constituting the warp prevention layer is in the range of -15 × 10 ^-6 /°C or more and 10 × 10 ^-6 /°C or less Stopper sheet.
[2] The sealing member sheet for a surface emitting device according to [1], wherein the thickness of the sealing member is 50 μm or more and 800 μm or less.
[3] The surface emitting device sealing member sheet according to [1] or [2], wherein the sealing member contains a thermoplastic resin.
[4] The surface emission according to any one of [1] to [3], wherein the sealing member has a polyethylene-based resin having a density of 0.870 g/cm ³ or more and 0.930 g/cm ³ or less as a base resin. Device sealing member sheet.
[5] The surface emitting device according to any one of [1] to [4], wherein the sealing member has a core layer and a skin layer arranged on at least one side of the core layer. Sealing member sheet.
[6] The surface emitting device sealing member sheet according to [5], wherein the core layer and the skin layer have different melting points of thermoplastic resins contained as base resins.
[7] The surface emitting device sealing member sheet according to [6] or [7], wherein the sealing member has a thermoplastic resin having a melting point of 90° C. or higher and 120° C. or lower as a base resin of the core layer. .
[8] The core layer of the sealing member is made of polyethylene resin having a density of 0.900 g/cm ³ or more and 0.930 g/cm ³ or less as a base resin, and the skin layer has a density of 0.875 g/cm ³ or more. The surface emitting device according to any one of [5] to [7], wherein the base resin is a polyethylene-based resin having a density of 0.910 g/cm ³ or less and a density lower than that of the base resin for the core layer. Sealing member sheet.
[9] A surface light-emitting device for use in a surface light-emitting device, in which a sealing member for sealing a light-emitting diode element and an anti-foaming layer disposed on one side of the sealing member are laminated. A sealing member sheet for a surface light-emitting device, wherein the elastic modulus of the material constituting the anti-foaming layer is 500 MPa or more.
[10] A surface light-emitting device for use in a surface light-emitting device, in which a sealing member for sealing a light-emitting diode element and an anti-foaming layer disposed on one side of the sealing member are laminated. A sealing member sheet for a surface light-emitting device, wherein the melting point of the material constituting the anti-foaming layer is 140° C. or higher.
[11] A light-emitting diode substrate having a support substrate and a light-emitting diode element arranged on one surface side of the support substrate; A sealing member for sealing, a warp prevention layer disposed on a surface of the sealing member opposite to the light emitting diode substrate, and a surface of the warp prevention layer disposed on a surface opposite to the light emitting diode substrate and a diffusion member, wherein the sealing member has a haze value of 4% or more, a thickness greater than the thickness of the light emitting diode element, and a linear expansion of a material constituting the warp prevention layer. A surface light-emitting device having a coefficient in the range of -15×10 ^-6 /°C to 10×10 ^-6 /°C.
[12] A light-emitting diode substrate having a support substrate and a light-emitting diode element arranged on one surface side of the support substrate; A sealing member for sealing, a diffusion member arranged on the surface of the sealing member opposite to the light emitting diode substrate, and a warp arranged on the surface of the light emitting diode substrate opposite to the light emitting diode element a prevention layer, wherein the sealing member has a haze value of 4% or more, a thickness greater than the thickness of the light emitting diode element, and a linear expansion of a material constituting the warp prevention layer. A surface light-emitting device having a coefficient equal to or greater than a linear expansion coefficient of a material forming the sealing member.
[13] The surface emitting device according to [11] or [12], wherein the sealing member has a thickness of 50 μm or more and 800 μm or less.
[14] The surface emitting device according to any one of [11] to [13], wherein the sealing member contains a thermoplastic resin.
[15] The surface emitting light according to any one of [11] to [14], wherein the sealing member has a polyethylene-based resin having a density of 0.870 g/cm ³ or more and 0.930 g/cm ³ or less as a base resin. Device.
[16] The surface emitting device according to any one of [11] to [15], wherein the sealing member has a core layer and a skin layer arranged on at least one side of the core layer.
[17] The surface emitting device according to [16], wherein the core layer and the skin layer have different melting points of thermoplastic resins contained as base resins.
[18] The surface emitting device according to [16] or [17], wherein the sealing member has a thermoplastic resin having a melting point of 90°C or higher and 120°C or lower as a base resin of the core layer.
[19] The core layer of the sealing member is made of polyethylene resin having a density of 0.900 g/cm ³ or more and 0.930 g/cm ³ or less as a base resin, and the skin layer has a density of 0.875 g/cm ³ or more. The surface emitting device according to any one of [16] to [18], wherein the base resin is a polyethylene-based resin having a density of 0.910 g/cm ³ or less and a density lower than that of the base resin for the core layer.
[20] A display device comprising a display panel and the surface emitting device according to any one of [11] to [19] arranged behind the display panel.
[21] The method for manufacturing a surface emitting device according to [11], wherein the warpage prevention layer, the sealing member, and the light emitting diode element are arranged so as to face the sealing member side. A method of manufacturing a surface emitting device, comprising the steps of: preparing a laminate in which substrates are arranged in this order; and thermocompression bonding the laminate.
[22] The method for manufacturing a surface emitting device according to [11], comprising: thermocompression bonding a first laminate in which the warpage prevention layer and the sealing member are laminated; a step of thermocompression bonding a second laminate in which the light-emitting diode substrate arranged so that the light-emitting diode element is on the sealing member side of the first laminate is placed on the surface of the first laminate on the sealing member side; A method for manufacturing a surface emitting device.

DESCRIPTION OF

SYMBOLS

1, 10... Surface-emitting device 2... Support substrate 3... LED element 4... LED substrate 5... Sealing member 6... Diffusion member 7... Warpage prevention layer 100... Display device

Claims

a sealing member that seals the light-emitting diode element;
A warp prevention layer disposed on the sealing member and having a coefficient of linear expansion in the range of −15×10 −6 /° C. or more and 10×10 −6 /° C. or less;
A sealing member sheet for a surface emitting device.
The sealing member sheet for a surface emitting device according to claim 1, wherein the thickness of the sealing member is 50 µm or more and 800 µm or less.
The sealing member sheet for a surface emitting device according to claim 1, wherein the sealing member contains a thermoplastic resin.
The sealing member sheet for a surface emitting device according to claim 1, wherein the sealing member has a polyethylene resin having a density of 0.870 g/cm 3 or more and 0.930 g/cm 3 or less as a base resin.
The sealing member sheet for a surface emitting device according to claim 1, wherein the sealing member has a core layer and a skin layer arranged on at least one side of the core layer.
The sealing member sheet for a surface emitting device according to claim 5, wherein the core layer and the skin layer have different melting points of the thermoplastic resin contained as the base resin.
The surface emitting device sealing member sheet according to claim 6, wherein the sealing member has a thermoplastic resin having a melting point of 90°C or higher and 120°C or lower as a base resin of the core layer.
The core layer in the sealing member uses a polyethylene resin with a density of 0.900 g/cm 3 or more and 0.930 g/cm 3 or less as a base resin, and the skin layer has a density of 0.875 g/cm 3 or more and 0.910 g. /cm 3 or less, and the base resin is a polyethylene-based resin having a density lower than that of the base resin for the core layer.
A surface light-emitting device sealing member for use in a surface light-emitting device, wherein a sealing member for sealing a light-emitting diode element and an anti-foaming layer disposed on one side of the sealing member are laminated. a sheet,
A sealing member sheet for a surface light-emitting device, wherein the elastic modulus of the material constituting the anti-foaming layer is 500 MPa or more.
A surface light-emitting device sealing member for use in a surface light-emitting device, wherein a sealing member for sealing a light-emitting diode element and an anti-foaming layer disposed on one side of the sealing member are laminated. a sheet,
A sealing member sheet for a surface light-emitting device, wherein the melting point of the material constituting the anti-foaming layer is 140° C. or higher.
a light-emitting diode substrate having a support substrate and a light-emitting diode element disposed on one side of the support substrate;
a sealing member disposed on the surface of the light emitting diode substrate on the side of the light emitting diode element and sealing the light emitting diode element;
a warp prevention layer disposed on a surface of the sealing member opposite to the light emitting diode substrate;
and a diffusion member disposed on a surface of the warp prevention layer opposite to the light emitting diode substrate, the surface emitting device comprising:
The sealing member has a haze value of 4% or more and a thickness greater than the thickness of the light emitting diode element,
A planar light-emitting device, wherein the coefficient of linear expansion of the material forming the anti-warpage layer is in the range of -15×10 -6 /°C to 10×10 -6 /°C.
a light-emitting diode substrate having a support substrate and light-emitting diode elements disposed on one surface of the support substrate;
a sealing member disposed on the surface of the light emitting diode substrate on the side of the light emitting diode element and sealing the light emitting diode element;
a diffusion member disposed on a surface of the sealing member opposite to the light emitting diode substrate;
and a warp prevention layer disposed on the surface of the light emitting diode substrate opposite to the light emitting diode element, the surface emitting device comprising:
The sealing member has a haze value of 4% or more and a thickness greater than the thickness of the light emitting diode element,
A surface light-emitting device, wherein a coefficient of linear expansion of a material forming the anti-warp layer is equal to or greater than a coefficient of linear expansion of a material forming the sealing member.
The surface emitting device according to claim 11 or 12, wherein the sealing member has a thickness of 50 µm or more and 800 µm or less.
The surface emitting device according to claim 11 or 12, wherein the sealing member contains a thermoplastic resin.
13. The surface emitting device according to claim 11, wherein said sealing member has a polyethylene resin having a density of 0.870 g/cm 3 or more and 0.930 g/cm 3 or less as a base resin.
The surface emitting device according to claim 11 or 12, wherein the sealing member has a core layer and a skin layer arranged on at least one side of the core layer.
The surface emitting device according to claim 16, wherein said core layer and said skin layer have different melting points of thermoplastic resins contained as base resins.
17. The surface emitting device according to claim 16, wherein the sealing member has a thermoplastic resin having a melting point of 90° C. or higher and 120° C. or lower as a base resin of the core layer.
The core layer in the sealing member uses a polyethylene resin with a density of 0.900 g/cm 3 or more and 0.930 g/cm 3 or less as a base resin, and the skin layer has a density of 0.875 g/cm 3 or more and 0.910 g. /cm 3 or less, and the surface emitting device according to claim 16, wherein the base resin is a polyethylene-based resin having a density lower than that of the base resin for the core layer.
a display panel;
A display device comprising the surface emitting device according to claim 11 or 12 arranged behind the display panel.
A method for manufacturing a surface emitting device according to claim 11,
A laminate is prepared in which the warpage prevention layer, the sealing member, and the light-emitting diode substrate arranged so that the light-emitting diode element is on the side of the sealing member are arranged in this order, and the laminate is thermocompression bonded. A method for manufacturing a surface emitting device, comprising steps.
A method for manufacturing a surface emitting device according to claim 11,
a step of thermocompression bonding a first laminate in which the warpage prevention layer and the sealing member are laminated;
a step of thermocompression bonding a second laminated body in which the light emitting diode substrate arranged so that the light emitting diode elements are on the sealing member side is arranged on the surface of the thermocompressed first laminated body on the side of the sealing member; and,
A method for manufacturing a surface emitting device, comprising: