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

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

[Technical field]

[0001] The present disclosure relates to a surface-emitting device, a display device using the same, a method for manufacturing the surface-emitting device, and a sealing member sheet for a surface-emitting device. [Background technology]

[0002] In recent years, in the field of display devices, there is a demand for higher quality displays. Display devices using light-emitting diode elements have the advantages of high brightness and high contrast, and have attracted attention, and their development is underway. In the following description, "light-emitting diode" may be referred to as "LED". For example, development of a backlight using LED elements as a backlight for use in a liquid crystal display device is underway. The backlight is also called a mini LED backlight.

[0003] Here, LED backlights are broadly divided into direct-light type and edge-light type. In small and medium-sized display devices such as mobile terminals such as smartphones, edge-light type LED backlights are usually used, but from the standpoint of brightness, the use of direct-light type LED backlights is being considered. On the other hand, in large display devices such as large-screen LCD TVs, direct-light type LED backlights are often used.

[0004] Direct-type LED backlights have a structure in which multiple LED elements are arranged on a substrate. In such direct-type LED backlights, by independently controlling multiple LED elements, it is possible to achieve so-called local dimming, which adjusts the brightness of each area of ​​the LED backlight according to the brightness and darkness of the displayed image. This makes it possible to significantly improve the contrast of the display device and reduce power consumption. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2013 / 018902 Summary of the Invention [Problem to be solved by the invention]

[0006] In surface emitting devices such as direct-type LED backlights, a diffusion plate or a transmissive reflector (hereinafter, diffusion member) is arranged above the LED elements in order to suppress unevenness in brightness. In order to suppress unevenness in brightness, it is necessary to arrange the LED elements and the diffusion member apart from each other. For this reason, in the past, pins or spacers have been arranged to maintain a predetermined distance between the LED elements and the diffusion member (for example, Patent Document 1). FIG. 12(a) shows a conventional LED backlight 60 in which a pin 65 is arranged to ensure a distance d between an LED element 63 on a support substrate 62 and a diffusion member 66. FIG. 12(b1) shows a conventional LED backlight 61 in which a spacer 67 is arranged between a support substrate 62 and a diffusion member 66, and FIG. 12(b2) is a schematic plan view of the spacer 67.

[0007] In this way, when pins or spacers are arranged, the light emitted from the LED element may be blocked or reflected by the pins or spacers, resulting in uneven brightness. For this reason, for example, in Patent Document 1, it is necessary to further arrange a diffusion plate or the like above the transmissive reflector, making it difficult to make the module thinner. Thus, the conventional surface light-emitting device has a problem in that it is difficult to simultaneously achieve uniform brightness in the surface and a thin design.

[0008] In order to solve such problems, it is conceivable to dispose a sealing member having light diffusion properties between the LED support substrate supporting the LED and the diffusion member. This makes it possible to improve the in-plane uniformity of brightness while achieving a thin design, which may solve the above problems. However, in a surface light-emitting device having the above LED support substrate and sealing member, there is a possibility that a problem such as warping may occur during manufacturing, etc.

[0009] The present disclosure has been made in consideration of the above-mentioned problems, and has as its main object to provide a surface emitting device that can prevent the occurrence of warping during manufacturing, etc., and improve the yield during the manufacturing of surface emitting devices. [Means for solving the problem]

[0010] In order to achieve the above object, the present disclosure provides a sealing member for sealing a light-emitting diode element, and a thermal expansion coefficient of ... -6 / ℃ or more 10×10 -6 The present invention provides a sealing member sheet for a surface emitting device, the sealing member sheet having a warp prevention layer having a thermal expansion coefficient in the range of 100 / °C or less.

[0011] The present disclosure also provides a sealing member sheet for a surface-emitting device, which is used in a surface-emitting device and is formed by laminating a sealing member for sealing a light-emitting diode element and an anti-foaming layer arranged on one surface side of the sealing member, wherein the elastic modulus of a material constituting the anti-foaming layer is 500 MPa or more.

[0012] The present disclosure provides a sealing member sheet for a surface-emitting device, which is used in a surface-emitting device and is formed by laminating a sealing member for sealing a light-emitting diode element and an anti-foaming layer arranged on one side of the sealing member, wherein the melting point of a material constituting the anti-foaming layer is 140°C or higher.

[0013] The present disclosure also relates to a surface light emitting device having a support substrate and a light emitting diode substrate having a light emitting diode element disposed on one surface side of the support substrate, a sealing member disposed on a surface of the light emitting diode substrate facing 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 diffusing member disposed on a surface of the warp prevention layer opposite to the light emitting diode substrate, the sealing member having a haze value of 4% or more and a thickness greater than a thickness of the light emitting diode element, and a linear expansion coefficient of a material constituting the warp prevention layer being within a range of −15×10 -6 / ℃ or more 10×10 -6 / °C or less.

[0014] The present disclosure further provides a surface-emitting device comprising: a supporting substrate; a light-emitting diode substrate having a light-emitting diode element disposed on one side of the supporting substrate; a sealing member disposed on a surface of the light-emitting diode substrate facing the light-emitting diode element and sealing the light-emitting diode element; a diffusing member disposed on a surface of the sealing member opposite the light-emitting diode substrate; and an anti-warping layer disposed on a surface of the light-emitting diode substrate opposite the light-emitting diode element, wherein the sealing member has a haze value of 4% or more and a thickness greater than a thickness of the light-emitting diode element, and the linear expansion coefficient of a material constituting the anti-warping layer is equal to or greater than the linear expansion coefficient of a material constituting the sealing member.

[0015] The present disclosure provides a display device including a display panel and the above-described surface-emitting device disposed on a rear surface of the display panel.

[0016] The present disclosure provides a method for manufacturing the above-mentioned surface-emitting device, which includes a step of preparing a laminate in which the anti-warping layer, the sealing member, and the light-emitting diode substrate arranged in this order so that the light-emitting diode element is on the sealing member side, and thermocompression bonding the laminate.

[0017] The present disclosure provides a method for manufacturing the above-mentioned surface-emitting device, comprising the steps of: thermocompression bonding a first laminate in which the anti-warping layer and the sealing member are stacked; and thermocompression bonding a second laminate in which the light-emitting diode substrate is arranged so that the light-emitting diode element faces the sealing member on the surface of the thermocompression-bonded first laminate facing the sealing member. Effect of the Invention

[0018] The present disclosure has an effect of providing a surface emitting device that can prevent occurrence of warping during manufacturing etc. and improve the yield during manufacturing of the surface emitting device. [Brief description of the drawings]

[0019] [Figure 1] 1 is a schematic cross-sectional view illustrating a surface emitting device according to the present disclosure. [Diagram 2] 5A to 5C are process diagrams illustrating an example of a method for forming a sealing member according to the present disclosure. [Diagram 3] 3 is a schematic cross-sectional view illustrating the structure of a sealing member of a surface emitting device according to the present disclosure. [Figure 4] 4 is a schematic cross-sectional view showing an example of a second diffusing member. FIG. [Diagram 5] 1 is a schematic cross-sectional view showing an example of a surface emitting device including a second diffusing member according to the present disclosure. [Figure 6] 1 is a graph illustrating a transmitted light intensity distribution. [Figure 7] 3A and 3B are a schematic plan view and a cross-sectional view showing an example of a first embodiment of a reflective structure of a second diffusing member. [Figure 8] 5A and 5B are a schematic plan view and a cross-sectional view showing an example of a second embodiment of the reflective structure of the second diffusing member. [Figure 9] 11 is a schematic cross-sectional view showing another example of the second embodiment of the reflective structure of the second diffusing member. FIG. [Figure 10] 10 is a schematic cross-sectional view showing another example of a surface emitting device according to the present disclosure. [Figure 11] FIG. 1 is a schematic diagram illustrating an example of a display device according to the present disclosure. [Figure 12] 1 is a schematic cross-sectional view of a conventional LED backlight. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The following describes the embodiments of the present disclosure with reference to the drawings. However, the present disclosure can be implemented in many different forms, and is not to be interpreted as being limited to the description of the embodiments exemplified below. In addition, in order to make the explanation clearer, the drawings may show the width, thickness, shape, etc. of each member as compared to the embodiments, but these are merely examples and do not limit the interpretation of the present disclosure. In this specification and each figure, the same reference numerals are used to designate elements similar to those described above with respect to the previously-mentioned figures, and detailed descriptions may be omitted as appropriate.

[0021] In this specification, when expressing an aspect in which another component is placed on a certain component, the term "on the face side" is used, unless otherwise specified, to include both a case in which another component is placed directly above or below a certain component so as to be in contact with the certain component, and a case in which another component is placed above or below a certain component with another component in between.

[0022] In addition, in this specification, the terms "sheet," "film," "plate," and the like are not distinguished from one another solely on the basis of differences in name. For example, the term "sheet" is used to include members also known as films and plates.

[0023] As described above, in the newly proposed surface emitting device including the LED support substrate and sealing member, there is a problem that warping may occur during manufacturing or the like.

[0024] The inventors of the present invention conducted extensive research to solve the above-mentioned new problem, and discovered that the cause of warping is the difference in linear expansion coefficient between the LED support substrate and the sealing member after they are thermally compressed together during manufacturing. As a result, the above problem was solved by arranging a warp prevention layer, whose linear expansion coefficient has a predetermined relationship with the sealing member, at an appropriate position relative to the sealing member.

[0025] A. Surface light emitting device The surface emitting device according to the present disclosure can be divided into three aspects, which will be described below in detail.

[0026] I. First embodiment Hereinafter, the 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 a surface light emitting device of this embodiment. As illustrated in Fig. 1, the surface light emitting device 1 has a support substrate 2, an LED substrate 4 having an LED element 3 arranged on one side of the support substrate 2, a sealing member 5 arranged on the LED substrate 4 on the side of the LED element 3 side and sealing the LED element 3, a diffusing member 6 arranged on the opposite side of the sealing member 5 to the LED substrate 4 side, and a warp prevention layer 7 arranged between the sealing member 5 and the diffusing member 6. The sealing member 5 in this embodiment has a haze value of 4% or more, a thickness d that is greater than the thickness of the LED element 3, and a linear expansion coefficient of the material constituting the warp prevention layer 7 that is greater than -15 x 10 -6 / ℃ or more 10×10 -6 / °C or less.

[0027] Generally, in a surface-emitting device, when, for example, a method such as thermocompression bonding is used to join the sealing member and the LED substrate, warping may occur during subsequent cooling due to the difference in linear expansion coefficient between the LED substrate and the sealing member. Furthermore, when the surface emitting device is used at extremely high or low temperatures, warping may occur due to the difference in linear expansion coefficient between the LED substrate and the sealing member.

[0028] The present embodiment has been made to solve such problems, and the warp prevention layer is disposed between the sealing member and the diffusing member, and the linear expansion coefficient of the material constituting the warp prevention layer is −15×10 -6 / ℃ or more 10×10 -6 / °C or less, the above-mentioned problem of warping is solved.

[0029] Furthermore, in conventional surface emitting devices, for example, when the surface emitting device is used for a long time at extremely high temperatures, there is a problem that air bubbles are generated between the LED substrate and the sealing member. This is caused by gas generated from the LED substrate by heating, or by air that is trapped between the LED substrate and a reflective layer, etc., when the reflective layer, etc. is provided on the LED substrate, and seeps out along the interface.

[0030] The LED element sealed in the sealing material has a higher light extraction efficiency than an unsealed LED element because the sealing material and the light-emitting surface of the LED element are directly bonded to each other, reducing the refractive index difference at the interface. However, if such bubbles are present, the above-mentioned improvement in light extraction efficiency cannot be obtained, resulting in a problem of lowering the light-emitting efficiency of the surface-emitting device. In this embodiment, the above-mentioned problem is also solved by providing the warp prevention layer. Hereinafter, the surface emitting device of this embodiment will be described in detail with respect to each of its components.

[0031] 1. Sealing member The sealing member in this embodiment has a haze value of 4% or more and a thickness greater than that of the LED element. The sealing member is optically transparent and is disposed on the light emitting surface side of the LED substrate.

[0032] (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 less than the above value, the brightness 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, and more preferably 30% or less. In this specification, the haze value is a value of the sealing member as a whole, and can be measured by cutting out the sealing member from the surface emitting device and using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory) according to a method conforming to JIS K7136:2000.

[0033] The method of adjusting the haze value to obtain the above-mentioned haze value is not particularly limited, but includes a method of utilizing the degree of crystallinity of the resin, a method of changing the content of fine particles in the resin, etc. 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, the effect of reducing the straight transmitted light can be obtained.

[0034] (2) Thickness The thickness of the sealing member in this embodiment may be any thickness as long as it is thicker than the LED element, and specifically, it is 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.

[0035] In this specification, the "thickness" is measured using a contact type film thickness measuring device (Mitutoyo thickness gauge 547-301). The same applies to the measurement of size such as "size".

[0036] If the thickness is smaller than the above range, the thickness is insufficient and the light emitted from the LED element cannot be diffused over the entire light-emitting surface, making it impossible to improve the brightness uniformly within the surface.

[0037] (3) Sealing material The material contained in the sealing member in this embodiment is not particularly limited as long as it has the above-mentioned haze value, but is preferably a thermoplastic resin, etc. By using a thermoplastic resin, for example, the haze value can be adjusted to be higher than when a thermosetting resin is used, and further, the sealing member can be formed at a low temperature.

[0038] In addition, when the sealing member contains a thermoplastic resin, a sheet-like sealing member (hereinafter, sometimes referred to as a sealing member sheet) composed of a sealing material composition containing a thermoplastic resin can be used. FIG. 2 is a process diagram showing an example of a method for 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 arranged on one surface are prepared, and the surface of the sealing member sheet 5a opposite to the warp prevention member 7 is laminated on the surface of the LED substrate 4 on the LED element 3 side. Next, by pressing them together using, for example, a vacuum lamination method, a laminate of the sealing member 5 having a warp prevention layer 7 arranged on one side and the LED substrate 4 can be formed as shown in FIG. 2(b).

[0039] 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, the thickness of the end portion may become thicker or thinner than that of the center portion due to surface tension or other factors. In addition, in the case of a curable resin, the volume of the resin may shrink during curing, and as a result, the thickness of the sealing member may become uneven between the center and the end portions after curing. If the thickness of the sealing member is not uniform in this way, brightness unevenness may occur.

[0040] In contrast, when a sheet-like sealing material is used, it is possible to avoid surface irregularities on the sealing member, such as the occurrence of thickness distribution in the coating film due to surface tension and the occurrence of thickness distribution due to thermal or optical shrinkage, which occur when a liquid sealing material is used. Therefore, a sealing member with good flatness can be obtained, and a display device of higher quality can be provided.

[0041] (a) Thermoplastic resin In this embodiment, the thermoplastic resin may be an olefin resin, an ethylene-vinyl acetate copolymer (EVA), a polyvinyl butyral resin, or the like.

[0042] Among them, the thermoplastic resin is preferably an olefin resin. This is because the olefin resin is particularly unlikely to produce components that deteriorate the LED substrate and has a low melt viscosity, so that the LED element can be well sealed. Among the olefin resins, polyethylene resins, polypropylene resins, and ionomer resins are preferable.

[0043] Here, the polyethylene resin in this specification includes not only ordinary polyethylene obtained by polymerizing ethylene, but also resins obtained by polymerizing a compound having an ethylenically unsaturated bond such as an α-olefin, resins obtained by copolymerizing a plurality of different compounds having an ethylenically unsaturated bond, and modified resins obtained by grafting another chemical species onto these resins.

[0044] In particular, in order to obtain the above haze value, the sealing member in this embodiment has a density of 0.870 g / cm 3 More than 0.930g / cm 3 It is preferable to use the following polyethylene resin as the base resin. In particular, it has a density of 0.890 g / cm 3 More than 0.930g / cm 3 It is preferable to use the following polyethylene-based resin as the base resin. When the sealing member is a multi-layer member as described later, it is preferable to use a polyethylene-based resin having the above density as the base resin of the core layer. The density is measured according to JIS Z 8807:2012. In this disclosure, the term "base resin" refers to the resin that has the largest content by mass among the resin components of a resin composition containing the base resin.

[0045] A silane copolymer (hereinafter also referred to as "silane copolymer") obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as a comonomer 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 can be one described in JP 2018-50027 A.

[0046] (b) Melting point The melting point of the thermoplastic resin used in this embodiment is not particularly limited as long as it can seal the LED element, but is preferably, for example, 90° C. or higher and 135° C. or lower. In particular, it is preferable that the thermoplastic resin does not soften due to heat generated during LED light emission, and it is preferable to use a thermoplastic resin having a temperature of 90° C. or higher and 120° C. or lower.

[0047] The melting point of the thermoplastic resin can be measured, for example, by differential scanning calorimetry (DSC) in accordance with the method for measuring transition temperature of plastics (JIS K7121:2012). In the case where a plurality of thermoplastic resins are contained, it is the value of the highest melting point. In the case where the sealing member is a multi-layer 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.

[0048] (c) Melt mass flow rate (MFR) In addition, the thermoplastic resin used in this embodiment is preferably one that has a melt viscosity that, when heated, can conform to the unevenness of the LED elements and other components arranged on one side of the LED substrate and penetrate into the gaps.

[0049] Specifically, the melt mass flow rate (MFR) of the thermoplastic resin used is preferably 0.5 g / 10 min or more and 40 g / 10 min or less, more preferably 2.0 g / 10 min or more and 40 g / 10 min or less, and even more preferably 2.0 g / 10 min or more and 20 g / 10 min or less. By having the MFR in the above range, it is possible for the resin to penetrate into the gaps between the LED elements and the like, to exhibit sufficient sealing performance, and furthermore, to provide a sealing member having excellent adhesion to the LED substrate.

[0050] In this specification, MFR refers to the value measured at 190°C under a load of 2.16 kg according to JIS K7210-1:2014 Method A. However, the MFR of polypropylene resin refers to the MFR value measured at 230°C under a load of 2.16 kg according to JIS K7210-1:2014 Method A.

[0051] When the sealing member is a multi-layer member as described below, the MFR is measured using the above-mentioned measurement method while all layers are in a multi-layered state in which they are laminated together, and the measured value obtained is the MFR value of the multi-layer sealing member.

[0052] d) Tensile modulus In addition, the thermoplastic resin in this embodiment preferably has a tensile modulus of elasticity 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, for example, when an impact is applied to the surface light emitting device from the outside. When the sealing member is a multi-layer member as described later, it is preferable to use a thermoplastic resin having the above modulus of elasticity as the base resin of the core layer. The above tensile modulus of elasticity is a value measured according to JIS K7127:1999.

[0053] The elastic modulus is measured by the tensile measurement described below. Measurement equipment: Instron universal material testing machine 5565 Load cell: 1kN Sample width: 10mm Chuck distance: 50mm ·Speed: 300mm / min

[0054] In addition to the above-mentioned thermoplastic resin, additives such as an antioxidant and a light stabilizer may be added to the sealing member.

[0055] e) Linear expansion coefficient In this embodiment, the sealing member has a higher linear expansion coefficient than the LED substrate, which will be described later. Therefore, as described above, after the sealing member and the LED substrate are thermocompressed in the manufacturing process, the shrinkage rate of the sealing member becomes larger than that of the LED substrate, resulting in a problem that the sealing member side is warped so as to be recessed. The linear expansion coefficient of the material constituting the sealing member used in this embodiment is set to a lower limit of 20×10 -6 / °C or more, and particularly 150×10 -6 / °C or more. On the other hand, the upper limit is preferably 1500×10 -6 / °C or less, and particularly 1000×10 -6 / °C or less. Specifically, it is 20×10 -6 / ℃ or more 1500×10 -6 / ℃ or less, and 20×10 -6 / ℃ or more 1000×10 -6 / °C or less, and of these, 150×10 -6 / ℃ or more 1000×10 -6 / ° C. The linear expansion coefficient is preferably a value measured according to JIS K7197:2012.

[0056] (4) Structure of sealing material 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. 1, or may be a multi-layer member in which multiple resin layers (two layers in FIG. 3(a) and three layers in FIG. 3(b)) including a core layer 51 and a skin layer 52 arranged on at least one surface of the core layer 51 are laminated, as shown in FIG. 3. In particular, a two-layer structure having a core layer or the like and a skin layer arranged 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.

[0057] 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 thickness ratio of the skin layer to the core layer (skin layer:core layer) is 1:X, and the lower limit of X is preferably 0.1 or more, and more preferably 0.5 or more. On the other hand, the lower limit is preferably 10 or less, and more preferably 6 or less. That is, it is preferably 1:0.1 to 1:10, and more preferably 1:0.5 to 1:6.

[0058] Furthermore, when the sealing member in this embodiment is a multilayer member having a three-layer structure, when the thickness ratio of the skin layer to the core layer (skin layer:core layer:skin layer) is 1:Y:1, Y is preferably 1 or more, and more preferably 2 or more, while Y is preferably 10 or less, and more 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, and more preferably 1:2:1 to 1:8:1.

[0059] When the sealing member in this embodiment is a multi-layer member, it is preferable that the core layer and the skin layer have, as base resins, the above-mentioned thermoplastic resins having different density ranges, melting points, etc. This is because it becomes easy to ensure the above-mentioned haze value in the core layer while ensuring adhesion and molding properties to the LED substrate in the skin layer.

[0060] In the case of the multilayer member, it is possible to use a material that is usually expensive and has good adhesion and molding properties that can penetrate into the gaps between LED elements, etc., for the skin layer located on the LED substrate side of the multilayer member. In the multilayer member, the material constituting the skin layer located 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 thermoplastic resin, it is preferable to use the above-mentioned silane copolymer, etc. In addition, in the case of the thermoplastic resin, it is also preferable that the material contains the above-mentioned olefin resin and a silane coupling agent. In addition, additives such as antioxidants and light stabilizers may be added to this layer.

[0061] (5) Preferred sealing materials The sealing member in this embodiment is preferably a multi-layer member composed of a plurality of layers including a core layer and a skin layer disposed on at least one of the outermost surfaces, and the core layer has a density of 0.900 g / cm 3 More than 0.930g / cm 3 The following polyethylene resin is preferably used as the base resin, and the skin layer has a density of 0.875 g / cm 3 More than 0.910g / cm 3 It is preferable to use a polyethylene-based resin having a density of 0.1 to 100 nm or less and a lower density than the base resin for the core layer as the base resin.

[0062] As the base resin for the core layer, low-density polyethylene resin (LDPE), linear low-density polyethylene resin (LLDPE), or metallocene linear low-density polyethylene resin (M-LLDPE) can be preferably used. Among them, from the viewpoint of long-term reliability, low-density polyethylene resin (LDPE) is particularly preferably used as the base resin for the core layer.

[0063] The density of the polyethylene resin used as the base resin for the core layer is 0.900 g / cm 3 More than 0.930 g / cm 3 More preferably, it is 0.920 g / cm 3 By setting the density of the base resin for the core layer in the above range, the haze value of the sealing member in this embodiment can be set to the above specific value or more. In addition, the sealing member can be provided with necessary and sufficient heat resistance without undergoing a crosslinking treatment.

[0064] The melting point of the polyethylene resin used as the base resin for the core layer is preferably 90°C or more and 135°C or less, and more preferably 90°C or more and 115°C or less. By setting the melting point within the above range, the heat resistance and molding characteristics of the sealing member can be maintained within a preferred range. It is possible to increase the melting point of the sealing member 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, the 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.

[0065] The polypropylene contained in the core layer is preferably a homopolypropylene (homoPP) resin. HomoPP is a polymer consisting of only 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 encapsulant composition for the core layer, the dimensional stability of the encapsulating member can be improved. In addition, the homoPP used as an additive resin to the encapsulant composition for the core layer preferably has an MFR of 5 g / 10 min or more and 125 g / 10 min or less at 230 ° C. and a load of 2.16 kg measured in accordance with JIS K7210:2014 A method. If the MFR is too small, the molecular weight becomes large and the rigidity becomes too high, making it difficult to ensure the desired sufficient flexibility of the encapsulating composition. In addition, if the MFR is too large, the fluidity during heating is not sufficiently suppressed, and the encapsulating member sheet cannot be provided with sufficient heat resistance and dimensional stability.

[0066] 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, more preferably 1.5 g / 10 min or more and 6.0 g / 10 min or less, at 190° C. and a load of 2.16 kg. 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 a preferred range. In addition, the processability during film formation can be sufficiently improved, which contributes to improving the productivity of the sealing member.

[0067] The content of the base resin in the total resin components of the core layer is 70% by mass or more and 99% by mass or less, and preferably 90% by mass or more and 99% by mass or less. As long as the content of the base resin is within the above range, other resins may be contained.

[0068] As the base resin for the skin layer of the above-mentioned sealing member, 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, as in the case of the sealing material composition for the core layer. 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.

[0069] The density of the polyethylene resin used as the base resin for the skin layer is 0.875 g / cm 3 More than 0.910g / cm 3 More preferably, 0.899 g / cm 3 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 preferred range.

[0070] The melting point of the polyethylene resin used as the base resin for the skin layer is preferably from 50° C. to 100° C., and more preferably from 55° C. to 95° C. By keeping the melting point within this range, the adhesion of the sealing member can be further reliably improved.

[0071] 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, more preferably 1.5 g / 10 min or more and 6.0 g / 10 min or less, at 190° C. and a load of 2.16 kg. 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, the processability during film formation can be sufficiently improved, contributing to improving the productivity of the sealing member.

[0072] The content of the base resin in the total resin components for the skin layer is 60% by mass or more and 99% by mass or less, and preferably 90% by mass or more and 99% by mass or less. As long as the base resin is contained within the above range, other resins may be contained.

[0073] It is more preferable that all the above-described sealing material compositions contain a certain amount of a silane copolymer obtained by copolymerizing an α-olefin and an ethylenically unsaturated silane compound as a comonomer, if necessary. Such a graft copolymer increases the degree of freedom of the silanol group that contributes to the adhesive force, and therefore can improve the adhesiveness of the sealing member to other members.

[0074] The silane copolymer can be, for example, the silane copolymer described in JP-A-2003-46105. By using the silane copolymer as a component of the sealing material composition, it is possible to obtain a sealing member that is excellent in strength, durability, and other properties, and is also excellent in weather resistance, heat resistance, water resistance, light resistance, and other properties, and further has extremely excellent heat fusion properties without being affected by manufacturing conditions such as heat and pressure bonding when arranging the sealing member, and can be obtained stably and at low cost.

[0075] As the silane copolymer, any of random copolymer, alternating copolymer, block copolymer and graft copolymer can be preferably used, but graft copolymer is more preferable, and graft copolymer in which polyethylene for polymerization is main chain and ethylenically unsaturated silane compound is polymerized as side chain is more preferable.Such graft copolymer has high degree of freedom of silanol group that contributes to adhesive force, so that it can improve adhesiveness of sealing member.

[0076] The content of the ethylenically unsaturated silane compound when forming the copolymer of α-olefin and ethylenically unsaturated silane compound is, for example, 0.001% by mass to 15% by mass, preferably 0.01% by mass to 10% by mass, particularly preferably 0.05% by mass to 5% by mass. When the content of the ethylenically unsaturated silane compound constituting the copolymer of α-olefin and ethylenically unsaturated silane compound is high, the mechanical strength and heat resistance are excellent, but when the content is excessive, the tensile strain and heat fusion property tend to be inferior.

[0077] The content of the silane copolymer in the total resin components of the encapsulant composition is preferably 0% by mass or more and 20% by mass or less in the encapsulant composition for the core layer, and 5% by mass or more and 40% by mass or less in the encapsulant composition for the skin layer. In particular, it is more preferable that the encapsulant composition for the skin layer contains 5% by mass or more of the silane copolymer. The amount of silane modification in the 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 encapsulant composition is based on the premise that the amount of silane modification is within this range, and it is desirable to finely adjust it appropriately according to the variation of the amount of modification.

[0078] All layers of the sealing member may contain additives such as antioxidants and light stabilizers. In addition, an adhesion improver can be added as appropriate. By adding an adhesion improver, the adhesion durability with other members can be made higher. As the adhesion improver, a known silane coupling agent can be used, but it is particularly preferable to use vinyl trimethoxy silane having a vinyl group, vinyl triethoxy silane, a silane coupling agent having an epoxy group, or a silane coupling agent having a mercapto group.

[0079] (6) Total light transmittance The sealing member in this embodiment is not particularly limited as long as it can function as a surface emitting device, but it is preferably 70% or more, and more preferably 80% or more. The total light transmittance of the sealing member can be measured, for example, by a method in accordance with JIS K7361-1:1997.

[0080] (7) Method for forming sealing member As described above, the sealing member in this embodiment can be formed using a sealing member sheet composed of a sealing material composition containing the above-mentioned thermoplastic resin and other components. The sealing member sheet is prepared by molding an sealing material composition into a sheet shape by a conventionally known method.

[0081] When the sealing member is a multilayer member, a multilayer film having a two-layer structure consisting of a core layer and a skin layer disposed on one surface of the core layer is formed with each sealing material composition for the core layer and the skin layer to a predetermined thickness, so that a sealing member 5 having a two-layer structure consisting of a core layer 51 and a skin layer 52 can be manufactured, for example, as shown in FIG. 3(a). Alternatively, it is also possible to form a multilayer film having a three-layer structure in which skin layers are disposed on both surfaces of the core layer. This allows a sealing member 5 having a three-layer structure consisting of a skin layer 52, a core layer 51, and a skin layer 52 to be manufactured, for example, as shown in FIG. 3(b). Note that the configuration other than the sealing member 5 and the reflective layer R in FIG. 3 is the same as that in FIG. 1, so a description thereof will be omitted here.

[0082] 2. Anti-warping layer The warp prevention layer in this embodiment is a layer disposed between the sealing member and the diffusing member described below.

[0083] In this embodiment, warping can be prevented by setting the linear expansion coefficient of the material constituting the warp prevention layer in a predetermined range in a high temperature region. The reason why warping can be prevented by setting the linear expansion coefficient of the material constituting the warp prevention layer in a predetermined range is as follows.

[0084] That is, when manufacturing a surface emitting device, a process of thermocompression bonding a sealing member and an LED substrate may be included, but the sealing member will shrink more than the LED substrate when cooled after thermocompression bonding. At this time, since a warp prevention layer with a small linear expansion coefficient is disposed on the opposite side of the sealing member from the LED substrate, it is possible to reduce the degree of shrinkage on the sealing member side, and as a result, it is possible to suppress the occurrence of warping.

[0085] In addition, in this embodiment, by disposing the warp prevention layer, it is possible to suppress the deformation of the sealing member that occurs when bubbles are generated at the portion where bubbles are generated, and thus it is possible to prevent the generation of bubbles between the sealing member and the LED substrate as described above. In particular, the warp prevention layer having a predetermined elastic modulus and a predetermined melting point can effectively obtain the above effect.

[0086] a) Linear expansion coefficient The linear expansion coefficient of the material constituting the warp prevention layer in this disclosure is −15×10 -6 / ℃ or more 10×10 -6 / ℃ or less. In the present disclosure, the lower limit of the linear expansion coefficient is -10 × 10 -6 / °C or more. On the other hand, the upper limit is 5×10 -6 / °C or less, and particularly preferably 0 or less. That is, -10×10 -6 / ℃ or more 5×10 -6 / °C or less, and in particular -10×10-6 / ℃ or more 0×10 -6 / °C or less. On the other hand, taking into consideration the materials used, etc., it is usually -10×10 -6 / ℃ or more 5×10 -6 / ℃ or less. If it is lower than this, it may cause reverse warping. On the other hand, if it is higher than this, the warping prevention effect is insufficient.

[0087] In this embodiment, the linear expansion coefficient is measured by the following method. The dimensional change of a sheet cut to 5 mm x 20 mm was measured after heating in accordance with JIS K 7197:2012, and the linear expansion coefficient was calculated by averaging it from 100°C to 25°C. The linear expansion coefficient here is a positive value when contracting and a negative value when expanding. The measurement was performed using the following measuring device and under the following measuring conditions. Measurement equipment: Seiko Instruments Thermomechanical Apparatus (TMA / SS-6000) Constant load tension mode: 0.1mN Measurement temperature range: -50℃ to 160℃ - Temperature range for calculating linear expansion coefficient: 25℃ to 100℃

[0088] b) Elastic modulus The elastic modulus of the warp prevention layer used in this embodiment is preferably 500 MPa or more, particularly preferably 1000 MPa or more, and of these, more preferably 4000 MPa or more. If the elastic modulus is lower than the above range, the effect of preventing bubble generation and the effect of preventing warping are reduced. In addition, taking into consideration materials that are normally used, the elastic modulus is 5500 MPa or less.

[0089] In this embodiment, the elastic modulus is measured by the tensile measurement described below. (Measurement method) Measurement equipment: Instron universal material testing machine 5565 Load cell: 1kN Sample width: 10mm Chuck distance: 50mm ·Speed: 300mm / min

[0090] c) Thickness In this embodiment, the thickness of the anti-warping layer is preferably in the range of 35 μm to 188 μm, more preferably in the range of 50 μm to 150 μm, and particularly preferably in the range of 100 μm to 125 μm. If the thickness is within the above range, it is possible to obtain an anti-warping effect and an effect of suppressing the generation of bubbles, and it does not hinder the compactification of the device.

[0091] d) Transmittance and haze value The haze value of the warp prevention layer in this embodiment is preferably 40% or less, more preferably 20% or less, and even more preferably 10% or less. If the haze value is within the above range, it is possible to improve the in-plane uniformity of the luminance. If the haze value exceeds the above range, the light is absorbed while being scattered inside the sealing member, and the luminance decreases. The haze value can be measured by the same method as the haze value measuring method for the sealing member described above.

[0092] On the other hand, the total light transmittance of the warp prevention layer in this embodiment is preferably 80% or more, and particularly preferably 90% or more. Such a high total light transmittance can prevent a decrease in the brightness of the surface emitting device.

[0093] The total light transmittance of the warp prevention layer can be measured in accordance with JIS K7361-1 using a haze meter HM150 manufactured by Murakami Color Research Laboratory.

[0094] e) Melting point The melting point of the warp prevention layer in this embodiment is preferably 140° C. or higher, and particularly preferably 260° C. or higher. Taking into consideration materials that are commonly used, the upper limit is 350° C. or lower. The melting point in this embodiment can be measured, for example, by differential scanning calorimetry (DSC) in accordance with the method for measuring transition temperatures of plastics (JIS K7121).

[0095] In this embodiment, since the warp prevention layer has the above-mentioned melting point, it is possible to effectively prevent the generation of air bubbles even when the surface emitting device is used for a long period of time in a high-temperature environment.

[0096] f) Material The material constituting the warp prevention layer used in this embodiment is not particularly limited as long as it has the above-mentioned characteristics, but examples thereof include polyolefin, polyester, cellulose, acrylic resin, and polyimide resin. Examples of polyolefin include polypropylene (PP). Examples of polyester include polytetraethylene terephthalate (PET) and polyethylene naphthalate (PEN). Examples of cellulose include triacetyl cellulose (TAC). In this embodiment, PP and PET are preferred from the viewpoint of versatility and the like.

[0097] g)Other In this embodiment, it is preferable that the warp prevention layer and the sealing member are in close contact with each other, because this allows the warp prevention effect to be exhibited more efficiently. In this embodiment, "the warp prevention layer and the sealing member are in close contact with each other" refers to a state in which the two do not peel off under their own weight when taken out. Specifically, the adhesive strength is preferably at least 1 N. The adhesive strength can be measured by the following method in accordance with JIS K 6854-2:1999.

[0098] (Measurement method) The sealing material that is in contact with the PCB board is cut into a 25 mm width, and a vertical peel test (300 mm / min) is performed using a peel tester (Tensilon universal testing machine RTF-1150-H) to measure the adhesion strength.

[0099] The warp prevention layer and the sealing member can be bonded to each other by, for example, arranging them via an adhesive layer or by melting them by thermocompression bonding.

[0100] 3. LED board The LED substrate in this embodiment is a member in which a plurality of LED elements are arranged on one surface side of a support substrate.

[0101] (1) LED element The LED element is a component disposed on one surface 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 when made into a surface light-emitting device, and examples include LED elements that can emit white, blue, ultraviolet, infrared, etc.

[0102] The LED element can be a chip-shaped LED element. The form of the LED element can be, for example, a light-emitting part (also called an LED chip) itself, or a packaged LED (also called a chip LED) such as a surface-mount type or a chip-on-board type. The packaged LED can have, for example, a light-emitting part and a protective part that covers the light-emitting part and contains a resin. Specifically, when the LED element is the light-emitting part itself, the LED element can be, for example, a blue LED element, an ultraviolet LED element, or an infrared LED element. When the LED element is a packaged LED, the LED element can be, for example, a white LED element.

[0103] When the surface emitting device of this embodiment is a device that combines an LED element and the above-mentioned wavelength conversion member to irradiate white light, the LED element is preferably a blue LED element, an ultraviolet LED element, or an infrared LED element. The blue LED element can be combined with, for example, a yellow phosphor, or with a red phosphor and a green phosphor to generate white light. The ultraviolet LED element can be combined with, for example, a red phosphor, a green phosphor, and a blue phosphor to generate white light. 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 brightness.

[0104] In addition, when the LED element is a white LED element, the white LED element is appropriately selected depending on the light emission method of the white LED element, etc. 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 a combination of an ultraviolet LED, a red phosphor, a green phosphor, and a blue phosphor.

[0105] Therefore, the white LED element may have, for example, a red LED light-emitting section, a green LED light-emitting section, and a blue LED light-emitting section, a blue LED light-emitting section and a protective section containing red and green phosphors, a blue LED light-emitting section and a protective section containing yellow phosphors, or an ultraviolet LED light-emitting section and a protective section containing red, green, and blue phosphors.

[0106] Among these, it is preferable that the white LED element has a blue LED light-emitting section and a protective section containing red and green phosphors, a blue LED light-emitting section and a protective section containing yellow phosphors, or an ultraviolet LED light-emitting section and a protective section containing red, green and blue phosphors.

[0107] Among these, it is preferable that the white LED element has a blue LED light emitting part and a protective part containing red and green phosphors, or has a blue LED light emitting part and a protective part containing yellow phosphors, because the surface emitting device of this embodiment can irradiate white light with high brightness. The structure of the LED element can be the same as that of a general LED element.

[0108] The LED elements are usually arranged at equal intervals on one side of the support substrate. The arrangement of the LED elements is appropriately selected depending on the purpose and size of the surface light emitting device of this embodiment, the size of the LED elements, etc. The arrangement density of the LED elements is also appropriately selected depending on the purpose and size of the surface light emitting device of this embodiment, the size of the LED elements, etc.

[0109] The size (chip size) of the LED element can be a general chip size, but it is preferable that the chip size is called a mini LED. 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. Because the size of the LED element is small, the LED elements can be arranged at high density, that is, the interval (pitch) between the LED elements can be reduced, and the distance between the LED substrate and the diffusion member can be reduced, that is, the thickness of the sealing member can be reduced. This allows the surface light-emitting device to be made thinner and lighter.

[0110] (2) Support substrate The supporting substrate in this embodiment is a member that supports the LED elements, the sealing member, the diffusing member, and the like.

[0111] The supporting substrate may be transparent or opaque. The supporting substrate may be flexible or rigid. The material of the supporting substrate may be an organic material, an inorganic material, or a composite material in which both an organic material and an inorganic material are combined.

[0112] 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. When the material of the support substrate is a composite material, a glass epoxy substrate can be used as the support substrate. In addition, for example, a metal core substrate can 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.

[0113] The thickness of the support substrate is not particularly limited, and is appropriately selected depending on the presence or absence of flexibility or rigidity, the use and size of the surface emitting device of this embodiment, and the like. In this embodiment, the support substrate has a linear expansion coefficient lower than that of the sealing member, which causes a problem of warping after the sealing member is thermocompression-bonded in the manufacturing process, as described above.

[0114] The linear expansion coefficient of the support substrate used in this embodiment is usually 5×10 -6 / ℃ or more 100×10 -6 / ℃ or less.

[0115] (3)Other The LED substrate in this embodiment is not particularly limited as long as it has the above-mentioned support substrate and LED element, and can have a necessary configuration as appropriate. Such configurations can include wiring parts, terminal parts, insulating layers, reflective layers, heat dissipation members, etc. Each configuration can be the same as that used in known LED substrates.

[0116] The wiring portion is electrically connected to the LED element. The wiring portion is usually arranged in a pattern. The wiring portion can be arranged on a support substrate via an adhesive layer. The wiring portion can be made of a metal material, a conductive polymer material, or the like.

[0117] The wiring section is electrically connected to the LED element by a joint section, which may be made of a conductive material such as a metal or conductive polymer, such as a bonding agent or solder.

[0118] A reflective layer can be arranged on the surface of the support substrate on which the LED elements are arranged, except for 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 can be made to enter the first layer of the diffusing member again, thereby improving the light utilization efficiency.

[0119] The reflective layer can be the same as the reflective layer generally used in the LED substrate. Specifically, the reflective layer can be a white resin film containing metal particles, inorganic particles or pigment and resin, a metal film, a porous film, etc. The thickness of the reflective layer is not particularly limited as long as it can obtain a desired reflectance, and can be appropriately set. The LED substrate can be formed by a known method.

[0120] 4. Diffusion material The diffusing member is disposed on the surface of the sealing member opposite to the LED substrate side. The diffusing member is not particularly limited as long as it has the function of diffusing the light emitted from the LED element and uniformly emitting the light in the surface direction, and examples of the diffusing member include the following first diffusing member, second diffusing member, and third diffusing member.

[0121] 4.1 First Diffusing Member The first diffusion member usually has at least a resin layer in which a diffusion agent is dispersed. The diffusion member may be, for example, a resin sheet in which a diffusion agent is dispersed, or a laminate having a resin layer in which a diffusion 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 diffusion agent, but is preferably a thermoplastic resin. This is because the diffusion member can be formed using a resin sheet in which a diffusion agent is dispersed, and therefore the flatness can be improved.

[0122] The thermoplastic resin used for the diffusing member is not particularly limited as long as it has high light transmittance, and any resin that is generally used in the field of display devices can be used.

[0123] The material of the diffusing agent is not particularly limited as long as it can diffuse the light from the LED element, and may be, for example, 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 mentioned. On the other hand, when the material of the diffusing agent is an inorganic material, TiO2, SiO2, Al2O3, silicon, etc. can be mentioned.

[0124] The refractive index of the diffusing agent is not particularly limited as long as it can diffuse the light from the LED element, and 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 deviation method, deviation analysis, mode line method, ellipsometry method, etc. 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.

[0125] The proportion of the diffusing agent in the diffusing member is not particularly limited as long as it can diffuse the light from the LED element, and is, for example, 40% by weight or more and 60% by weight or less.

[0126] 4.2 Secondary Diffuser The second diffusion member is a member having a first layer and a second layer in this order from the LED substrate side, the first layer having light transmittance and light diffusion properties, the second layer having a reflectance that increases as the absolute value of the incident angle of light to the surface of the second layer on the first layer side decreases, and a transmittance that increases as the absolute value of the incident angle of light to the surface of the second layer on the first layer side increases. In this embodiment, by having the above-mentioned diffusion member, it is possible to further improve the in-plane uniformity of luminance and to achieve a thin structure. In addition, it is also possible to reduce costs and power consumption.

[0127] The second diffusing member will be described below with reference to the drawings. FIG. 4 is a schematic cross-sectional view showing an example of the second diffusing member. As illustrated in FIG. 4, the diffusing member 11 has a first layer 12 and a second layer 13 in this order. The first layer 12 has light transmissivity and light diffusivity, and transmits and diffuses light L1 and L2 incident from the surface 12A of the first layer 12 opposite to the surface of the first layer 12. The second layer 13 has a reflectance that increases as the absolute value of the incident angle of light to the surface 13A of the second layer 13 on the first layer 12 side decreases, and has a transmittance that increases as the absolute value of the incident angle of light to the surface 13A of the second layer 13 on the first layer 12 side increases. Therefore, the second layer 13 can reflect light L1 incident at a low incident angle θ1 to the surface 13A of the second layer 13 on the first layer 12 side, and transmit light L2 incident at a high incident angle θ2 to the surface 13A of the second layer 13 on the first layer 2 side. The low incidence angle refers to an incidence angle whose absolute value is small, and the high incidence angle refers to an incidence angle whose absolute value is large.

[0128] Fig. 5 is a schematic cross-sectional view showing an example of a surface emitting device of this embodiment including the second diffusion member shown in Fig. 4. As illustrated in Fig. 5, a surface emitting device 10 has an LED substrate 4 having LED elements 3 arranged on one surface of a support substrate 2, a sealing member 5 arranged on the surface of the LED substrate 4 facing the LED elements 3 and sealing the LED elements 3, and a diffusion member 11 arranged on the surface of the sealing member 5 opposite the LED substrate 4 side. The diffusion member 11 is arranged such that a surface 11A on the first layer 12 side faces the sealing member 5.

[0129] As shown in Fig. 4, light incident from surface 11A of diffusing member 11 on the first layer 12 side is diffused by the first layer 12, and light L1 incident at a low incident angle θ1 on surface 13A of second layer 13 on the first layer 12 side of the light transmitted through the first layer 12 and diffused can be reflected by surface 13A of second layer 13 on the first layer 12 side and diffused by being incident again on the first layer 12. Then, light L2, L2' incident at a high incident angle θ2 on surface 13A of second layer 13 on the first layer 12 side of the light transmitted through the first layer 12 and diffused can be transmitted through the second layer 13 and emitted from surface 11B of diffusing member 11 on the second layer 13 side.

[0130] Furthermore, by combining the first layer and the second layer, light incident from the surface of the diffusing member on the first layer side, particularly light incident from the surface of the diffusing member on the first layer side at a low incident angle, can be diffused by passing through the first layer many times, and can be emitted from the surface of the diffusing member on the second layer side at a high emission 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, and the in-plane uniformity of brightness can be further improved.

[0131] In addition, by combining the first and second layers, light incident at a low angle from the first layer surface of the diffusing member can be transmitted through the first layer multiple times, making it possible to lengthen the optical path length from when the light enters the first layer surface of the diffusing member until it exits from the second layer surface of the diffusing member. This makes it possible for a portion of the light emitted from the LED element and then exiting from the second layer surface of the diffusing member to be emitted from a position away from the LED element in the in-plane direction, rather than directly above the LED element.

[0132] (1)First layer The first layer in this embodiment is disposed on one side of the second layer described below, and is a member having light transmission and light diffusion properties. The light transmission of the first layer is, for example, preferably a total light transmittance of 50% or more, more preferably 70% or more, and particularly preferably 90% or more. By having the total light transmittance of the first layer within the above range, the brightness of the surface emitting device of this embodiment can be increased.

[0133] The total light transmittance of the first layer can be measured, for example, by a method in accordance with JIS K7361-1:1997.

[0134] The light diffusion of the first layer may be, for example, a light diffusion that randomly diffuses light, or a light diffusion that mainly diffuses light in a specific direction. The light diffusion that mainly diffuses light in a specific direction is a property that deflects light, that is, a property that changes the traveling direction of light. When the light diffusion of the first layer is a light diffusion that randomly diffuses light, for example, the diffusion angle of light incident on the first layer may be 10° or more, 15° or more, or 20° or more. In addition, the diffusion angle of light incident on the first layer may be, for example, 85° or less, 60° or less, or 50° or less. When the diffusion angle is within the above range, the in-plane uniformity of the luminance of the surface emitting device of this embodiment can be further improved.

[0135] 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, the diffusion angle α is defined as the full width at half maximum (FWHM), which is the difference between two angles at which the maximum transmitted light intensity Imax of the light emitted from the other surface of the first layer when light is incident perpendicularly on one surface of the first layer constituting the diffusion member is half.

[0136] The diffusion angle can be measured using a goniophotometer or a goniospectrophotometer. The diffusion angle can be measured using a goniophotometer GP-200 manufactured by Murakami Color Research Laboratory.

[0137] The first layer is not particularly limited as long as it has the above-mentioned light transmission and light diffusion properties, and examples thereof include a transmission type diffraction grating, a microlens array, and a diffusion agent-containing resin film containing a diffusion agent and a resin. Specifically, when the first layer has a light diffusion property that mainly diffuses light in a specific direction, examples thereof include a transmission type diffraction grating and a microlens array. On the other hand, when the first layer has a light diffusion property that randomly diffuses light, examples thereof include a diffusion agent-containing resin film. Among them, from the viewpoint of light diffusion properties, a transmission type diffraction grating and a microlens array are preferable. Note that a transmission type diffraction grating is also called a transmission type diffractive optical element (DOE; Diffractive Optical Elements).

[0138] 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-mentioned light transmittance and light diffusion. The pitch of the transmission type diffraction grating, etc., is adjusted appropriately as long as the above-mentioned light transmittance and light diffusion are obtained. Specifically, when the wavelength output by the LED element is a single color such as red, green, or blue, it is possible to effectively bend the light from the LED element by setting the pitch according to each wavelength.

[0139] The material constituting the transmission type diffraction grating may be any material that can provide a transmission type diffraction grating having the above-mentioned light transmittance and light diffusion properties, and may be any material that is generally used for transmission type diffraction gratings. The method for forming the transmission type diffraction grating may be the same as the method for forming a general transmission type diffraction grating.

[0140] When the first layer is a microlens array, the microlens array is not particularly limited as long as it has the above-mentioned light transmittance and light diffusion properties. The shape, pitch, size, etc. of the microlenses are appropriately adjusted as long as they can obtain the above-mentioned light transmittance and light diffusion properties. The material constituting the microlens may be a material that can obtain a microlens having the above-mentioned light transmittance and light diffusion properties, and may be a material generally used for a microlens. In addition, the method of forming the microlens may be the same as the method of forming a general microlens.

[0141] 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-mentioned light transmittance and light diffusibility.

[0142] The first layer may have a structure capable of exhibiting light diffusion properties, and may exhibit light diffusion properties in the entire layer, or may exhibit light diffusion properties on a surface. Examples of those that exhibit light diffusion properties on a surface include a relief type diffraction grating and a microlens array. On the other hand, examples of those that exhibit light diffusion properties in the entire layer include a volume type diffraction grating and a resin film containing a diffusing agent. Examples of methods for laminating the first layer and the second layer include a method of bonding the first layer and the second layer via an adhesive layer or a pressure-sensitive adhesive layer, and a method of directly forming the first layer on one surface of the second layer. Examples of methods for directly forming the first layer on one surface of the second layer include a printing method and resin shaping using a mold.

[0143] (2)Second layer The second layer in this embodiment is a member that is disposed on one side of the first layer and has an incidence angle dependency of reflectance such that the reflectance increases as the absolute value of the incidence angle of light with respect to the surface of the second layer facing the first layer decreases, and an incidence angle dependency of transmittance such that the transmittance increases as the absolute value of the incidence angle of light with respect to the surface of the second layer facing the first layer increases.

[0144] The second layer has an incidence angle dependency of reflectance such that the reflectance increases as the absolute value of the incidence angle of light on the surface of the second layer on the first layer side decreases. That is, the reflectance of light incident at a low incidence angle on the surface of the second layer on the first layer side is greater than the reflectance of light incident at a high incidence angle on the surface of the second layer on the first layer side. In particular, it is preferable that the reflectance of light incident at a low incidence angle on the surface of the second layer on the first layer side is large.

[0145] Specifically, the specular reflectance of visible light incident on the surface of the second layer on the first layer side at an incident angle of ±60° or less is preferably 50% or more and less than 100%, more preferably 80% or more and less than 100%, and 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 the incident angle of ±60°. By having the specular reflectance in the above range, the in-plane uniformity of the brightness of the surface emitting device of this embodiment can be further improved.

[0146] Moreover, the average 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, for example, preferably 80% to 99%, more preferably 90% to 97%. The average regular reflectance refers to the average regular reflectance of visible light at each incident angle. By having the average regular reflectance within the above range, the in-plane uniformity of the luminance of the surface emitting device in this embodiment can be further improved.

[0147] Moreover, the specular reflectance of visible light incident at an incident angle of 0° (perpendicularly incident) on the surface of the second layer on the first layer side is, for example, preferably 80% or more and less than 100%, more preferably 90% or more and less than 100%, and particularly preferably 95% or more and less than 100%. By having the specular reflectance in the above range, the in-plane uniformity of the luminance of the surface emitting device of this embodiment can be further improved.

[0148] In this specification, "visible light" refers to light having a wavelength of 380 nm or more and 780 nm or less. The regular reflectance can be measured using a goniophotometer or a goniospectrophotometer. The regular reflectance can be measured using a goniophotometer GP-200 manufactured by Murakami Color Research Laboratory.

[0149] The second layer has a transmittance dependency on the incident angle such that the transmittance increases as the absolute value of the incident angle of light on 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 greater than the transmittance of light incident on the surface of the second layer on the first layer side at a low incident angle. In particular, the transmittance of light incident on the surface of the second layer on the first layer side at a high incident angle is preferably large. 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, more preferably 40% or more, and particularly preferably 50% or more. It is preferable that the total light transmittance satisfies the above range at all incident angles of 70° or more and less than 90°. In addition, it is preferable that the total light transmittance satisfies the above range when the absolute value of the incident angle is 70° or more and less than 90°. By the total light transmittance being in the above range, the in-plane uniformity of the luminance of the surface emitting device of this embodiment can be further improved.

[0150] The total light transmittance of the second layer can be measured, for example, using a goniophotometer or a goniospectrophotometer in accordance with a method conforming to JIS K7361-1: 1997. The total light transmittance can be measured using a UV-Vis-Near-Infrared Spectrophotometer V-7200 manufactured by JASCO Corporation.

[0151] The second layer is not particularly limited as long as it has the above-mentioned reflectance and transmittance dependence on the incident angle, and various configurations having the above-mentioned reflectance and transmittance dependence on the incident angle can be adopted. Examples of the second layer include a dielectric multilayer film, a reflection structure having a patterned first reflection film and a patterned second reflection film in order from the first layer side, the openings of the first reflection film and the openings of the second reflection film being positioned so as not to overlap in a plan view, and the first reflection film and the second reflection film being spaced apart in the thickness direction, and a reflection type diffraction grating.

[0152] Hereinafter, the case where the second layer is a dielectric multilayer film, a reflecting structure, or a reflecting diffraction grating will be described.

[0153] a) Dielectric multilayer film When the second layer is a dielectric multilayer film, examples of the dielectric multilayer film include a multilayer film of an inorganic compound in which inorganic layers having different refractive indices are alternately laminated, and a multilayer film of a resin in which resin layers having different refractive indices are alternately laminated.

[0154] (Multilayer film of inorganic compounds) When the dielectric multilayer film is a multilayer film of an inorganic compound in which inorganic layers having different refractive indices are alternately stacked, the multilayer film of the inorganic compound is not particularly limited as long as it has the above-mentioned incidence angle dependence of reflectance and transmittance.

[0155] 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, for example, 1.7 or more, and may be 1.7 or more and 2.5 or less. Examples of such inorganic compounds include those containing titanium oxide, zirconium oxide, tantalum pentoxide, niobium pentoxide, lanthanum oxide, yttrium oxide, zinc oxide, zinc sulfide, and indium oxide as main components, and containing small amounts of titanium oxide, tin oxide, and cerium oxide.

[0156] Among the inorganic layers having different refractive indices, the inorganic compound contained in the low refractive index inorganic layer may have a refractive index of, for example, 1.6 or less, and may be 1.2 or more and 1.6 or less. Examples of such inorganic compounds include silica, alumina, lanthanum fluoride, magnesium fluoride, and sodium aluminum hexafluoride.

[0157] The number of stacked high refractive index inorganic layers and low refractive index inorganic layers is adjusted appropriately as long as the above-mentioned reflectance and transmittance are dependent on the incidence angle. Specifically, the total number of stacked high refractive index inorganic layers and low refractive index inorganic layers can be 4 or more. In addition, the upper limit of the total number of stacked layers is not particularly limited, but since the number of stacked layers increases, the number of steps increases, for example, it can be 24 or less.

[0158] The thickness of the inorganic compound multilayer film may be, for example, 0.5 μm to 10 μm, as long as the above-mentioned dependence of reflectance and transmittance on the incidence angle is obtained. Methods for forming the inorganic compound multilayer film include a method in which high refractive index inorganic layers and low refractive index inorganic layers are alternately laminated by a CVD method, a sputtering method, a vacuum deposition method, a wet coating method, or the like.

[0159] (multi-layer resin film) When the dielectric multilayer film is a resin multilayer film in which resin layers having different refractive indices are alternately laminated, the resin multilayer film is not particularly limited as long as it has the above-mentioned incidence angle dependence of reflectance and transmittance.

[0160] Examples of the resin constituting the resin layer include thermoplastic resins and thermosetting resins. Among them, thermoplastic resins are preferred because of their good moldability.

[0161] The resin layer may contain various additives, such as antioxidants, antistatic agents, crystal nucleating agents, inorganic particles, organic particles, viscosity reducers, heat stabilizers, lubricants, infrared absorbers, ultraviolet absorbers, and dopants for adjusting the refractive index.

[0162] Examples of the thermoplastic resin include polyolefin resin, alicyclic polyolefin resin, polyamide resin, aramid resin, polyester resin, polycarbonate resin, polyarylate resin, polyacetal resin, polyphenylene sulfide resin, tetrafluoroethylene resin, trifluoroethylene resin, trifluorochloroethylene resin, tetrafluoroethylene-hexafluoropropylene copolymer, fluororesin such as vinylidene fluoride resin, acrylic resin, methacrylic resin, polyacetal resin, polyglycolic acid resin, and polylactic acid resin. Examples of the polyolefin resin include polyethylene, polypropylene, polystyrene, and polymethylpentene. Examples of the polyamide resin include nylon 6 and nylon 66. Examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polypropylene terephthalate, polybutyl succinate, and polyethylene-2,6-naphthalate. In the present disclosure, polyester is more preferable from the viewpoints of strength, heat resistance, and transparency.

[0163] In this specification, polyester refers to homopolyesters or copolymer polyesters that are polycondensates of dicarboxylic acid component skeletons and diol component skeletons. Here, examples of homopolyesters include polyethylene terephthalate, polypropylene terephthalate, polybutylene terephthalate, polyethylene-2,6-naphthalate, poly-1,4-cyclohexanedimethylene terephthalate, polyethylene diphenyl ester, etc. Among them, polyethylene terephthalate is preferable because it is inexpensive and can be used in a wide variety of applications.

[0164] In this specification, the copolymer polyester is defined as a polycondensate consisting of at least three or more components selected from the following components having a dicarboxylic acid skeleton and components having a diol skeleton. Examples of the 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 ester derivatives thereof. Examples of the components having a glycol skeleton include ethylene glycol, 1,2-propanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol, diethylene glycol, polyalkylene glycol, 2,2-bis(4-β-hydroxyethoxyphenyl)propane, isosorbate, 1,4-cyclohexanedimethanol, and spiroglycol.

[0165] Of the resin layers having different refractive indices, the difference in the in-plane average refractive index between the high refractive index resin layer and the low refractive index resin layer is preferably 0.03 or more, more preferably 0.05 or more, and even more preferably 0.1 or more. If the difference in the in-plane average refractive index is too small, sufficient reflectance may not be obtained.

[0166] In addition, 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 0.03 or less. In this case, even if the incident angle increases, the reflectance of the reflection peak is unlikely to decrease.

[0167] As a preferred combination of the high refractive index resin used in the high refractive index resin layer and the low refractive index resin used in the low refractive index resin layer, firstly, the absolute value of 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 difference in SP value is within the above range, interlayer peeling 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 refers to the repeating unit constituting the resin. For example, when one resin is polyethylene terephthalate, the basic skeleton is ethylene terephthalate. Also, for example, when one resin is polyethylene, the basic skeleton is ethylene. When the high refractive index resin and the low refractive index resin are resins containing the same basic skeleton, peeling between layers is more unlikely to occur.

[0168] Secondly, as a preferred combination of the high refractive index resin used in the high refractive index resin layer and the low refractive index resin used in the low refractive index layer, 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, the thickness uniformity may be poor when forming a laminated film of the high refractive index resin layer and the low refractive index resin layer. In addition, overstretching may occur when forming the laminated film.

[0169] It is also preferred that the high refractive index resin is polyethylene terephthalate or polyethylene naphthalate, and the low refractive index resin is polyester containing spiroglycol. Here, polyester containing spiroglycol refers to a copolyester copolymerized with spiroglycol, a homopolyester, or a polyester blended with them. Polyester containing spiroglycol is preferred because it is less likely to be overstretched during molding and less likely to peel off between layers due to its small difference in glass transition temperature from polyethylene terephthalate or polyethylene naphthalate.

[0170] More preferably, the high refractive index resin is polyethylene terephthalate or polyethylene naphthalate, and the low refractive index resin is a 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 between the polyester and polyethylene terephthalate or polyethylene naphthalate is large, so that a high reflectance is easily obtained. In addition, the difference in glass transition temperature between the polyester and polyethylene terephthalate or polyethylene naphthalate is small, and the adhesiveness is also excellent, so that the polyester is unlikely to be overstretched during molding, and is unlikely to peel off between layers.

[0171] It is also preferred that the high refractive index resin is polyethylene terephthalate or polyethylene naphthalate, and the low refractive index resin is a polyester containing cyclohexane dimethanol. Here, the polyester containing cyclohexane dimethanol refers to a copolyester copolymerized with cyclohexane dimethanol, a homopolyester, or a polyester blended with them. Polyester containing cyclohexane dimethanol is preferred because it is less likely to be overstretched during molding and less likely to peel off between layers due to its small difference in glass transition temperature from polyethylene terephthalate and polyethylene naphthalate. In this case, it is more preferred that the low refractive index resin is an ethylene terephthalate polycondensate in which the copolymerization amount of cyclohexane dimethanol is 15 mol% or more and 60 mol% or less.

[0172] By doing so, the ethylene terephthalate polycondensate has high reflectivity, but the change in optical properties due to heating or aging is small, and peeling between layers is also unlikely to occur. The ethylene terephthalate polycondensate having the copolymerization amount of cyclohexanedimethanol within the above range adheres very strongly to polyethylene terephthalate. In addition, the cyclohexanedimethanol group has a geometric isomer such as a cis isomer or a trans isomer, and a conformational isomer such as a chair isomer or a boat isomer, so that even when co-stretched with polyethylene terephthalate, it is unlikely to be oriented and crystallized, has a high reflectance, has even less change in optical properties due to heat history, and is unlikely to break during film formation.

[0173] In the above-mentioned resin multilayer film, there may be 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. In other words, it is preferable that the arrangement order of the high-refractive index resin layers and low-refractive index resin layers in the thickness direction is not random, and the arrangement order of the resin layers other than the high-refractive index resin layers and low-refractive index resin layers is not particularly limited. In addition, when the above-mentioned resin multilayer film has a high-refractive index resin layer, a low-refractive index resin layer, and other resin layers, the arrangement order of them is A(BCA), where A is the high-refractive index resin layer, B is the low-refractive index resin layer, and C is the other resin layers. n , A(BCBA) n , A(BABCBA) n It is more preferable that the layers are laminated in a regular sequence such as A(BCA) where n is the number of repeating units. n In the case of n=3, it represents layers stacked in the thickness direction in the order ABCABCABCA.

[0174] The number of layers of the high refractive index resin layer and the low refractive index resin layer may be appropriately adjusted as long as the above-mentioned dependence of the reflectance and the transmittance on the incident angle is obtained. Specifically, the high refractive index resin layer and the low refractive index resin layer may be alternately laminated in 30 layers or more, and may be laminated in 200 layers or more. The total number of layers of the high refractive index resin layer and the low refractive index resin layer may be, for example, 600 layers or more. If the number of layers is too small, sufficient reflectance may not be obtained. In addition, the desired reflectance can be easily obtained by the number of layers being within the above range. In addition, the upper limit of the total number of layers is not particularly limited, but considering the increase in size of the device and the decrease in lamination accuracy due to the number of layers becoming too large, it can be, for example, 1500 layers or less.

[0175] Furthermore, the multilayer film of the resin preferably has a surface layer containing polyethylene terephthalate or polyethylene naphthalate having a thickness of 3 μm or more on at least one side, and more preferably has the above surface layer on both sides. The thickness of the surface layer is more preferably 5 μm or more. By having the above surface layer, the surface of the multilayer film of the resin can be protected.

[0176] Examples of methods for producing the multi-layered film of the above resins include a co-extrusion method, etc. Specifically, reference can be made to the method for producing a laminated film described in JP-A-2008-200861.

[0177] As the multilayer film of the above resin, a commercially available laminate film can be used, and specific examples thereof include PICASUS (registered trademark) manufactured by Toray Industries, Inc. and ESR manufactured by 3M.

[0178] b) Reflective structure The reflective structure has, in order from the first layer side, a patterned first reflective film and a patterned second reflective film, the openings of the first reflective film and the openings of the second reflective film are positioned so that they do not overlap in a planar view, and the first reflective film and the second reflective film are arranged apart in the thickness direction.

[0179] The reflection structure has two aspects. The first aspect of the reflection structure has a transparent substrate, a patterned first reflection film arranged on one surface of the transparent substrate, and a patterned second reflection film arranged on the other surface of the transparent substrate, the openings of the first reflection film and the openings of the second reflection film are positioned so as not to overlap in a plan view, and the first reflection film and the second reflection film are arranged apart in the thickness direction. The second aspect of the reflection structure has a transparent substrate, a patterned convex portion arranged on one surface of the transparent substrate and having light transmission, a patterned first reflection film arranged on the surface opposite to the transparent substrate side of the convex portion, and a patterned second reflection film arranged on the openings of the convex portion on one surface of the transparent substrate, the openings of the first reflection film and the openings of the second reflection film are positioned so as not to overlap in a plan view, and the first reflection film and the second reflection film are arranged apart in the thickness direction. Each aspect will be described below.

[0180] (First embodiment of the reflective structure) A first aspect of the reflective structure in this embodiment has 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, in which the openings of the first reflective film and the openings of the second reflective film are positioned so as not to overlap in a planar view, and the first reflective film and the second reflective film are arranged apart in the thickness direction. In the case of the reflective structure of this embodiment, the first layer is disposed on the surface of the second diffusing member facing the first reflective film of the reflective structure.

[0181] 7(a) and (b) are schematic plan views and cross-sectional views showing an example of the reflective structure of this embodiment, in which FIG. 7(a) is a plan view of the reflective structure seen from the surface on the first reflective film side, and FIG. 7(b) is a cross-sectional view of line AA in FIG. 7(a). As shown in FIG. 7(a) and (b), the reflective structure 20 has a transparent substrate 21, a patterned first reflective film 22 arranged on one surface of the transparent substrate 21, and a second reflective film 24 arranged on the other surface of the transparent substrate 21. The openings 23 of the first reflective film 22 and the openings 25 of the second reflective film 24 are positioned so as not to overlap in a plan view. In addition, the first reflective film 22 and the second reflective film 24 are respectively arranged on both sides of the transparent substrate 21, and are arranged apart in the thickness direction. In FIG. 7(a), the openings of the second reflective film are indicated by dashed lines. In addition, FIG. 7(c) is a schematic cross-sectional view showing an example of a surface emitting device including a diffusing member having the reflective structure of this embodiment.

[0182] In such a reflective structure, the patterned first and second reflective films are laminated, and the openings of the first and second reflective films are positioned so as not to overlap in a plan view, so that when a diffusing member having the reflective structure of this embodiment is used in a surface-emitting device, at least one of the first reflective film 22 and the second reflective film 24 is always present directly above the LED element 3, as shown in Fig. 7(c), for example. Therefore, as shown in Fig. 7(b), for example, light L11 incident at a low incident angle on the surface of the reflective structure 20 on the first reflective film 22 side, i.e., the surface 13A on the side where the first layer (not shown) of the reflective structure 20 (second layer) is disposed, can be reflected by the first reflective film 22 and the second reflective film 24.

[0183] In addition, since the openings of the first reflecting film and the openings of the second reflecting film are positioned so as not to overlap in a plan view, and the first reflecting film and the second reflecting film are arranged apart in the thickness direction, the light L12, L13 incident at a high incident angle on the surface of the reflecting structure 20 on the first reflecting film 22 side, i.e., the surface 13A on the side on which the first layer (not shown) of the reflecting structure 20 (second layer) is arranged, can be emitted from the opening 23 of the first reflecting film 22 and the opening 25 of the second reflecting film 24. As a result, a part of the light emitted from the LED element and then emitted from the surface on the second layer side of the diffusing member can be emitted from a position away from the LED element in the in-plane direction, rather than directly above the LED element. Therefore, the in-plane uniformity of the luminance can be improved.

[0184] The first and second reflective films may be general reflective films, such as metal films and dielectric multilayer films. The metal film may be made of metal materials used in general reflective films, such as aluminum, gold, silver, and alloys thereof. The dielectric multilayer film may be made of materials used in general reflective films, such as inorganic compound multilayer films, such as multilayer films in which zirconium oxide and silicon oxide are alternately stacked. The materials contained in the first and second reflective films may be the same or different from each other.

[0185] The pitch of the openings of the first and second reflective films may be set appropriately depending on the light distribution characteristics, size, pitch and shape of the LED elements in the surface emitting device in which the diffusing member of this embodiment is used, the distance between the LED substrate and the diffusing member, etc. The pitch of the openings of the first and second reflective films may be the same or different from each other.

[0186] The pitch of the openings in the first reflective film may be larger than the size of the LED elements, for example. Specifically, the pitch of the openings in the first reflective film may be set to be 0.1 mm or more and 20 mm or less.

[0187] In addition, the pitch of the openings of the second reflective film is not particularly limited as long as it can suppress brightness unevenness, but it is preferably equal to or smaller than the pitch of the openings of the first reflective film, and is preferably smaller than the pitch of the openings of the first reflective film. 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, the pattern of the second reflective film and the openings of the second reflective film can be made difficult to see, and surface emission without unevenness can be achieved.

[0188] The pitch of the openings in the first reflective film refers to the distance P1 between the centers of the openings 23 in adjacent first reflective film 22, as shown in Fig. 7(a), for example. The pitch of the openings in the second reflective film refers to the distance P2 between the centers of the openings 25 in adjacent second reflective film 24, as shown in Fig. 7(a), for example.

[0189] The size of the openings of the first and second reflective films is set appropriately according to the light distribution characteristics, size, pitch, and shape of the LED elements, the distance between the LED substrate and the diffusing member, etc., as long as the above-mentioned dependence of reflectance and transmittance on the incident angle is obtained. The size of the openings of the first and second reflective films may be the same or different from each other.

[0190] Specifically, when the opening of the first reflective film has a rectangular shape, the size of the opening can be set to a length of 0.1 mm or more and 5 mm or less.

[0191] The size of the opening of the second reflective film is not particularly limited as long as it can suppress the unevenness of the brightness, but it is preferably equal to or smaller than the size of the opening of the first reflective film, and is preferably smaller than the size of the opening of the first 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, the pattern of the part of the second reflective film and the part of the opening of the second reflective film can be made difficult to see, and uneven surface emission can be achieved.

[0192] The size of the opening of the first reflective film refers to the length x1 of the opening 23 of the first reflective film 22 when the opening of the first reflective film is rectangular, as shown in Fig. 7(a). The size of the opening of the second reflective film refers to the length x2 of the opening 25 of the second reflective film 24, as shown in Fig. 7(a).

[0193] The shape of the openings of the first and second reflective films can be any shape, such as a rectangle or a circle. The thickness of the first and second reflective films is adjusted appropriately as long as the above-mentioned incidence angle dependence of the reflectance and transmittance is obtained. Specifically, the thickness of the first and second reflective films can be 0.05 μm or more and 100 μm or less.

[0194] The first and second reflective films may be formed on the surface of a transparent substrate, or may be sheet-shaped reflective films. The method of forming the first and second reflective films is not particularly limited as long as it is a method that can form a patterned reflective film on the surface of the transparent substrate, and examples of the method include sputtering and vacuum deposition. In addition, when the first and second reflective films are sheet-shaped reflective films, examples of the method of forming the openings include a method of forming a plurality of through holes by punching or the like. In this case, the method of laminating the transparent substrate and the sheet-shaped reflective film can be, for example, a method of bonding the sheet-shaped reflective film to the transparent substrate via an adhesive layer or a pressure-sensitive adhesive layer.

[0195] The transparent substrate in the reflective structure of this embodiment is a member that supports the above-mentioned first reflective film and second reflective film, and is also a member for arranging the first reflective film and the second reflective film at a distance from each other in the thickness direction.

[0196] The transparent substrate has light transmittance. The 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.

[0197] The material constituting the transparent substrate may be any material having the total light transmittance described above, and examples of such materials include resins such as polyethylene terephthalate, polycarbonate, acrylic, cycloolefin, polyester, polystyrene, and acrylic styrene, and glasses such as quartz glass, Pyrex (registered trademark), and synthetic quartz.

[0198] 7(b), the thickness of the transparent base material is preferably such that light L12 incident at a high incident angle on the surface of the reflection structure 20 on the first reflection film 22 side, i.e., the surface 13A on the side where the first layer (not shown) of the reflection structure 20 (second layer) is arranged, can be emitted from the opening 23 of the first reflection film 22 and the opening 25 of the second reflection film 24, and is appropriately set according to the pitch and size of the openings of the first reflection film and the second reflection film, the thickness of the first reflection film and the second reflection film, etc. Specifically, the thickness of the transparent base material can be 0.05 mm or more and 2 mm or less, and preferably 0.1 mm or more and 0.5 mm or less.

[0199] (Second embodiment of the reflective structure) A second embodiment of the reflective structure has a transparent substrate, a patterned convex portion having light transparency and disposed on one surface of the transparent substrate, a patterned first reflective film disposed on the surface opposite to the transparent substrate side of the convex portion, and a patterned second reflective film disposed at the opening of the convex portion on one surface of the transparent substrate, the opening of the first reflective film and the opening of the second reflective film being positioned so as not to overlap in a plan view, and the first reflective film and the second reflective film being disposed apart in the thickness direction. In the case of the reflective structure of this embodiment, a first layer is disposed on the surface side of the reflective structure facing the first reflective film in the second diffusing member.

[0200] 8(a) and (b) are schematic plan views and cross-sectional views showing an example of a second mode of the reflective structure in this embodiment, in which FIG. 8(a) is a plan view of the reflective structure seen from the surface on the first reflective film side, and FIG. 8(b) is a cross-sectional view along the line AA in FIG. 8(a). As shown in FIG. 8(a) and (b), the reflective structure 20 has a transparent substrate 21, a patterned convex portion 26 having light transmission arranged on one surface of the transparent substrate 21, a patterned first reflective film 22 arranged on the surface opposite to the transparent substrate 21 side surface of the convex portion 26, and a patterned second reflective film 24 arranged at the opening of the convex portion 26 on one surface of the transparent substrate 21. The opening 23 of the first reflective film 22 and the opening 25 of the second reflective film 24 are positioned so as not to overlap in a plan view. In addition, the first reflective film 22 and the second reflective film 24 are separated by the convex portion 26 and arranged apart in the thickness direction.

[0201] In such a reflective structure, the patterned first and second reflective films are laminated, and the openings of the first and second reflective films are positioned so as not to overlap in a plan view, so that in a surface emitting device (particularly, an LED backlight) using a diffusing member having the reflective structure of this embodiment, at least one of the first and second reflective films is always present directly above the LED element. Therefore, as in the first embodiment of the reflective structure, for example, as shown in FIG. 8(b), light L11 incident at a low incident angle on the surface of the reflective structure 20 on the first reflective film 22 side, i.e., the surface 13A on the side where the first layer (not shown) of the reflective structure 20 (second layer) is arranged, can be reflected by the first reflective film 22 and the second reflective film 24.

[0202] In addition, the openings of the first reflecting film and the openings of the second reflecting film are positioned so as not to overlap in a plan view, and the first reflecting film and the second reflecting film are arranged apart in the thickness direction, so that the light L12 incident at a high incident angle on the surface of the reflecting structure 20 on the first reflecting film 22 side, i.e., the surface 13A on the side on which the first layer (not shown) of the reflecting structure 20 (second layer) is arranged, can be emitted from the side surface of the convex portion 26 and the opening 25 of the second reflecting film 24. As a result, a part of the light emitted from the LED element and then emitted from the surface on the second layer side of the diffusing member can be emitted from a position away from the LED element in the in-plane direction, rather than directly above the LED element. Therefore, the in-plane uniformity of the luminance can be improved. In addition, in this embodiment, since the convex portion is provided, self-alignment of the openings of the first reflecting film and the second reflecting film is possible, and the manufacturing cost can be reduced.

[0203] The material of the first reflective film and the second reflective film, the pitch of the openings in the first reflective film and the second reflective film, the size of the openings in the first reflective film and the second reflective film, the shape of the openings in the first reflective film and the second reflective film, the thickness of the first reflective film and the second reflective film, and the method of forming the first reflective film and the second reflective film may be the same as in the first embodiment. Moreover, the transparent substrate may be the same as that of the first embodiment.

[0204] The convex portion in the reflection structure of this embodiment is a member for arranging the first reflection film and the second reflection film at a distance in the thickness direction. The convex portion has light transmittance. The light transmittance of the convex portion is preferably, for example, 80% or more, and more preferably 90% or more. The total light transmittance of the convex portion can be measured by a method conforming to JIS K7361-1:1997.

[0205] The material for forming the convex portions may be any material that can form patterned convex portions and has the above-mentioned total light transmittance, and examples of such materials include thermosetting resins and electron beam curable resins.

[0206] 8(b), for example, the height of the convex portion is preferably such that light L12 incident at a high incident angle on the surface of the reflecting structure 20 on the first reflecting film 22 side, i.e., the surface 13A on the side where the first layer (not shown) of the reflecting structure 20 (second layer) is arranged, can be emitted from the side surface of the convex portion 26 and the opening 25 of the second reflecting film 24, and is appropriately set according to the pitch and size of the openings of the first reflecting film and the second reflecting film, the thickness of the first reflecting film and the second reflecting film, etc. Specifically, the height of the convex portion can be 0.05 mm or more and 2 mm or less, and preferably 0.1 mm or more and 0.5 mm or less.

[0207] The pitch, size and planar shape of the convex portions can be the same as the pitch, size and shape of the openings of the second reflective film. The surface of the convex portions may be a smooth surface as shown in Fig. 8(b), or may be a rough surface as shown in Fig. 9(a). When the surface of the convex portions is a rough surface, the convex portions can be given light diffusibility.

[0208] 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 surface of the convex portion is curved, the convex portion can be provided with light diffusing properties.

[0209] The method for forming the convex portions is not particularly limited as long as it is a method capable of forming patterned convex portions, and examples thereof include a printing method and resin shaping using a mold.

[0210] 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-mentioned incidence angle dependence of reflectance and transmittance.

[0211] The pitch of the reflective diffraction grating is adjusted as appropriate so long as the above-mentioned reflectance and transmittance are dependent on the incident angle. Specifically, when the wavelength of the LED element is a single color such as red, green, or blue, the light of the LED element can be effectively reflected by setting the pitch according to each wavelength.

[0212] The material constituting the reflective diffraction grating may be any material that can provide a reflective diffraction grating having the above-mentioned incidence angle dependency of reflectance and transmittance, and may be any material that is generally used for reflective diffraction gratings. The method for forming the reflective diffraction grating may be the same as the method for forming a general reflective diffraction grating.

[0213] 4.3 Third Diffuser The third diffusion member is a resin plate having a light-transmitting resin such as polystyrene (PS) or polycarbonate, and may have a large number of voids inside or an uneven surface. Any of the types commonly used in the display device field may be used.

[0214] 5. Wavelength conversion materials In the surface-emitting device of this embodiment, for example, a wavelength conversion member may be arranged on the side of the diffusing member opposite the LED substrate side, or a wavelength conversion member may be arranged on the LED substrate side of the diffusing member.

[0215] The wavelength conversion member is a member that contains a phosphor that absorbs the light emitted from the LED element and emits excitation light. The wavelength conversion member has the function of generating white light when combined with the LED substrate.

[0216] The 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 wavelength conversion layer alone, or a laminate having a wavelength conversion layer on one side of a transparent substrate. Among them, a wavelength conversion layer alone is preferred from the viewpoint of thinning. More preferably, a sheet-shaped wavelength conversion member is used.

[0217] The phosphor can be appropriately selected according to the color of light emitted from the LED element, and examples thereof include blue phosphor, green phosphor, red phosphor, yellow phosphor, etc. For example, when the LED element is a blue LED element, the phosphor may be a green phosphor and a red phosphor, or a yellow phosphor. Also, when the LED element is an ultraviolet LED element, the phosphor may be a red phosphor, a green phosphor, and a blue phosphor.

[0218] As the phosphor, for example, a phosphor used in a wavelength conversion member of an LED backlight can be used. Also, quantum dots can be used as the phosphor. 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 can be the same as the content of the phosphor in the wavelength conversion member of a general LED backlight.

[0219] The resin contained in the wavelength conversion member is not particularly limited as long as it can disperse the phosphor. The resin may be the same as the resin used in the wavelength conversion member of a general LED backlight, and may be a thermosetting resin such as a silicone resin or an epoxy resin.

[0220] The thickness of the wavelength conversion member is not particularly limited as long as it can generate the desired white light when used in a surface emitting device, and can be, for example, 10 μm or more and 1000 μm or less.

[0221] 6. Other optical components In the surface emitting device of this embodiment, for example, an optical member may be further disposed on the surface of the diffusing member opposite to the surface on the LED substrate side. Examples of the optical member include a prism sheet and a reflective polarizing sheet.

[0222] (1) Prism sheet The prism sheet in this embodiment has a function of concentrating incident light and intensively improving the brightness in the front direction. The prism sheet is, for example, a transparent resin substrate on one side of which a prism pattern containing an acrylic resin is arranged. As the prism sheet, for example, a brightness enhancement film BEF series manufactured by 3M can be used.

[0223] (2) Reflective polarizing sheet The reflective polarizing sheet in this embodiment has a function of transmitting only a first linearly polarized component (e.g., P-polarized light) and reflecting a second linearly polarized component (e.g., S-polarized light) that is orthogonal to the first linearly polarized component without absorbing it. The second linearly polarized component reflected by the reflective polarizing sheet is reflected again and enters the reflective polarizing sheet again in a depolarized state (a state containing both the first linearly polarized component and the second linearly polarized component). Thus, the reflective polarizing sheet transmits the first linearly polarized component of the light that re-enters the sheet, and reflects again the second linearly polarized component that is orthogonal to the first linearly polarized component.

[0224] By repeating the above process, approximately 70% to 80% of the light emitted from the second layer is emitted as the first linearly polarized component. Therefore, when the surface-emitting device of this embodiment is used in a display device, by matching the polarization direction of the first linearly polarized component (transmission axis component) of the reflective polarizing sheet with the transmission axis direction of the polarizing plate of the display panel, all of 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 an image with higher brightness than when the reflective polarizing sheet is not provided.

[0225] As the reflective polarizing sheet, for example, a brightness enhancing film DBEF series manufactured by 3M Co., Ltd. In addition, as the reflective polarizing sheet, for example, a high brightness polarizing sheet WRPS and a wire grid polarizer manufactured by Shinwha Intertek Co., Ltd. can also be used.

[0226] 7.Applications The use of the surface emitting device in this embodiment is not particularly limited, but it can be suitably used in a display device. It can also be used in a lighting device, etc.

[0227] II. Second embodiment Next, a second embodiment of the surface emitting device of the present embodiment will be described. Fig. 10 is a schematic cross-sectional view showing an example of the surface light emitting device of this embodiment. As illustrated in Fig. 10, the surface light emitting device 1 of this embodiment has a support substrate 2, an LED substrate 4 having an LED element 3 arranged on one side of the support substrate 2, a sealing member 5 arranged on the LED substrate 4 on the side of the LED element 3 side and sealing the LED element 3, a diffusion member 6 arranged on the side of the sealing member 5 opposite to the LED substrate 4 side, and a warp prevention layer 7 arranged on the side of the LED substrate 4 opposite to the sealing member 5. The sealing member 5 in this embodiment has a haze value of 4% or more, a thickness thicker than the LED element 3, and a linear expansion coefficient of the material constituting the warp prevention layer 7 is equal to or larger than the linear expansion coefficient of the material constituting the sealing member 5.

[0228] In the surface-emitting device of this embodiment, if a method such as thermocompression bonding is used to join the sealing member and the LED substrate, warping may occur during subsequent cooling due to the difference in linear expansion coefficient between the LED substrate and the sealing member. Furthermore, when the surface emitting device is used at extremely high or low temperatures, warping may occur due to the difference in linear expansion coefficient between the LED substrate and the sealing member.

[0229] This embodiment, like the first embodiment, has been made to solve such problems, and the problem of warping described above is solved by disposing the anti-warp layer on the side of the LED substrate opposite the sealing member and making the linear expansion coefficient of the material constituting the anti-warp layer equal to or greater than the linear expansion coefficient of the material constituting the sealing member.

[0230] The surface emitting device of this embodiment will be described below. Note that this embodiment is similar to the first embodiment except for the position of the warp prevention layer and the material constituting the warp prevention layer, and therefore the description of the configuration other than the warp prevention layer will be omitted.

[0231] 1. Anti-warping layer The warp prevention layer in this embodiment is a layer disposed on the surface of the LED substrate opposite the sealing member. In this embodiment, the linear expansion coefficient of the material constituting the warp prevention layer is equal to or greater than that of the material constituting the sealing member. The reason why warping can be prevented by making the linear expansion coefficient of the material constituting the warp prevention layer equal to or greater than that of the material constituting the sealing member is as follows.

[0232] That is, when manufacturing a surface emitting device, a process of thermocompression bonding a sealing member and an LED substrate is included, and the sealing member shrinks more than the LED substrate when cooled after thermocompression bonding. At this time, a warp prevention layer with a linear expansion coefficient equal to or greater than that of the sealing member is disposed on the surface of the LED substrate opposite the sealing member, so that the warp prevention layer also shrinks in response to the shrinkage of the sealing member, making it possible to reduce the degree of warping of the LED substrate, and as a result, it becomes possible to suppress the occurrence of warping.

[0233] a) Linear expansion coefficient In this embodiment, the difference between the linear expansion coefficient of the material constituting the warp prevention layer and the linear expansion coefficient of the material constituting the sealing member is preferably as large as possible, but is limited to a certain extent in consideration of the material used for the sealing member. Therefore, the difference in linear expansion coefficient is usually 400×10 -6 / ℃ or less, or equivalent

[0234] In this embodiment, "equivalent" refers to a range of 0.8 to 1.2, particularly 0.95 to 1.0, where the linear expansion coefficient of the material constituting the sealing member is 1.

[0235] The linear expansion coefficient of the material that constitutes such a warp prevention layer is usually 300 × 10 -6 / ℃ or more 500×10 -6 / ℃ or less, especially 350×10 -6 / ℃ or more 450×10 -6 / ℃ or less is used. The method for measuring the linear expansion coefficient in this embodiment is the same as that described in the first embodiment.

[0236] b) Thickness The thickness of the warp prevention layer in this embodiment is preferably 25% or more of the thickness of the sealing member, particularly 35% or more, and more preferably 45% or more. The upper limit is set to 50% or less from the perspective of compactification of the device. If it is within the above range, it is possible to obtain the warp prevention effect and it does not hinder the compactification of the device.

[0237] c) Elastic modulus The elastic modulus of the warp prevention layer used in this embodiment is preferably equal to or greater than the elastic modulus of the sealing member. Specifically, when the elastic modulus of the sealing member is taken as 1, the elastic modulus is preferably 0.8 or more, and more preferably 0.9 or more. Generally, the elastic modulus is 2.5 or less.

[0238] The actual value is preferably 35 MPa or more, more preferably 40 MPa or more, and even more preferably 85 MPa or more. If the elastic modulus is lower than the above range, the warp prevention effect is reduced. In addition, taking into account materials that are commonly used, it is 300 MPa or less.

[0239] The elastic modulus is measured by the tensile measurement described below. Measurement equipment: Instron universal material testing machine 5565 Load cell: 1kN Sample width: 10mm Chuck distance: 50mm ·Speed: 300mm / min

[0240] d) Material The material constituting the warp prevention layer used in this embodiment is not particularly limited as long as it has the above-mentioned properties, but among them, materials similar to those used as sealing members can be used. A preferred material is an olefin resin, and among the olefin resins, polyethylene resin, polypropylene resin, and ionomer resin are preferred.

[0241] (2)Other In this embodiment, the warp prevention layer is preferably in close contact with the LED substrate, since this can further improve the warp prevention effect. The specific degree of adhesion etc. is the same as in the first embodiment, so a description thereof will be omitted here. Methods for adhering the anti-warping layer and the LED substrate include a method of placing an adhesive layer between the two and adhering them, and a method of melting and adhering the anti-warping layer by thermocompression bonding.

[0242] III. Third embodiment The surface emitting device of this embodiment uses an anti-foaming layer instead of the anti-warping layer in the first embodiment, and has two embodiments: an elastic modulus of the anti-foaming layer is 500 MPa or more, and a melting point of the anti-foaming layer is 140°C or more.

[0243] Conventional surface emitting devices have a problem that, for example, when the surface emitting device is used for a long time at extremely high temperatures, air bubbles are generated between the LED substrate and the sealing member. This can be caused by gas generated from the LED substrate by heating, or by air seeping out along the interface between the LED substrate and a reflective layer, etc., when the reflective layer, etc. is provided on the LED substrate.

[0244] The LED element sealed in the sealing material has a higher light extraction efficiency than an unsealed LED element because the sealing material and the light-emitting surface of the LED element are directly bonded to each other, reducing the refractive index difference at the interface. However, if such bubbles are present, the above-mentioned improvement in light extraction efficiency cannot be obtained, resulting in a problem of lowering the light-emitting efficiency of the surface-emitting device.

[0245] In this embodiment, by providing the foaming prevention layer having the above-mentioned characteristics, it is possible to suppress deformation of the surface of the sealing member that would be expected to occur during foaming, resulting in convex portions. As a result, even if gas is generated from the LED substrate, for example, the presence of the foam prevention layer applies pressure to the sealing member, making it possible to prevent the generated gas from turning into bubbles.

[0246] The elastic modulus of the foaming prevention layer used in this embodiment may be 500 MPa or more, preferably 1000 MPa or more, and more preferably 4000 MPa or more.

[0247] If the elastic modulus is lower than the above range, the effect of preventing the generation of bubbles is reduced. Considering commonly used materials, the strength is 5500 MPa or less.

[0248] The melting point of the foaming prevention layer in this embodiment may be 140° C. or higher, and is preferably 260° C. or higher. Taking into consideration materials that are commonly used, the upper limit is 350° C. or lower.

[0249] In this embodiment, it is more preferable to use a foaming prevention layer having the above-mentioned elastic modulus and melting point. The methods for measuring the elastic modulus and melting point are the same as those described in the first embodiment.

[0250] Unlike the warp prevention layer, the foaming prevention layer used in this embodiment does not necessarily have a linear expansion coefficient within a predetermined range. However, since the foaming prevention layer has a linear expansion coefficient similar to that of the warp prevention layer in the first embodiment, it can provide the same warp prevention effect as the first embodiment, and is therefore preferable.

[0251] Other points of the surface emitting device of this embodiment are the same as those of the surface emitting device of the first embodiment, except that the warp prevention layer is replaced with a foaming prevention layer, so a description thereof will be omitted here.

[0252] B.Display device The present disclosure provides a display device including a display panel and the above-described surface-emitting device disposed on a rear surface of the display panel.

[0253] 11 is a schematic diagram showing an example of a display device according to the present disclosure. As shown in FIG. 11, a display device 100 includes a display panel 31 and a surface emitting device 1 according to the present disclosure disposed on the rear surface of the display panel 31.

[0254] According to the present disclosure, by using the above-described surface-emitting device, it is possible to improve the in-plane uniformity of luminance while achieving a thinner display, thereby obtaining a high-quality display device.

[0255] 1. Surface light emitting device The surface emitting device in the present disclosure is similar to that described in the above section "A. Surface emitting device."

[0256] 2. Display panel The display panel in the present disclosure is not particularly limited, and examples thereof include a liquid crystal panel.

[0257] C. Manufacturing method of surface light emitting device The present disclosure provides a method for producing the surface emitting device of the first embodiment. The present disclosure can be divided into two embodiments.

[0258] I. First embodiment The manufacturing method of the surface emitting device of this embodiment is the manufacturing method described in the first embodiment of the surface emitting device, and is characterized by including a step of preparing a laminate in which the anti-warping layer, the sealing member, and the LED substrate arranged in this order with the LED element facing the sealing member, and thermocompression bonding the laminate. In this embodiment, first, a laminate in which the LED substrate, the sealing member, and the warp prevention layer are arranged in this order is prepared.

[0259] Here, the LED substrate, the sealing member, and the warp prevention layer are the same as those explained in the first embodiment of the surface emitting device, and therefore the explanation thereof will be omitted here. Next, a step of thermocompression bonding the laminate is carried out.

[0260] The thermocompression bonding method in this embodiment is not particularly limited as long as it is a method capable of thermocompression bonding, and may be a vacuum lamination method, a vacuum packing method, a thermal lamination method, or the like.

[0261] In this embodiment, a diffusing member is disposed on the warp prevention layer side of the laminate that has been pressed, and is bonded using an adhesive or the like, thereby making it possible to manufacture a surface emitting device.

[0262] II. Second embodiment The manufacturing method of the surface emitting device of this embodiment is the manufacturing method described in the first embodiment of the above surface emitting device, and is characterized by having a step of thermocompression bonding a first laminate in which the anti-warping layer and the sealing member are stacked, and a step of thermocompression bonding a second laminate in which the LED substrate is arranged so that the LED element is on the sealing member side surface of the thermocompression bonded first laminate.

[0263] In this embodiment, first, a first laminate in which the warp prevention layer and the sealing member are laminated is prepared, and then the first laminate is thermocompression-bonded by the same method as in the first embodiment.

[0264] Next, a second laminate in which the LED substrate is disposed on the surface of the thermocompression-bonded first laminate on the sealing member side is thermocompression-bonded in the same manner as in the first embodiment. In this embodiment, a diffusing member is disposed on the warp prevention layer side of the pressure-bonded second laminate, and is bonded using an adhesive or the like, thereby making it possible to manufacture a surface emitting device.

[0265] D. Sealing material sheet for surface emitting device The sealing member sheet for a surface emitting device according to the present disclosure has the following two aspects.

[0266] 1. First Aspect The sealing member sheet for a surface-emitting device of this embodiment is a sealing member sheet for a surface-emitting device, which is formed by laminating a sealing member for sealing an LED element and a warp prevention layer disposed on one surface side of the sealing member, and is used in a surface-emitting device, and the linear expansion coefficient of a material constituting the warp prevention layer is -15×10 -6 / ℃ or more 10×10 -6 / °C or less.

[0267] The surface-emitting device is formed by stacking, in this order, a support substrate, an LED substrate having the LED element arranged on one side of the support substrate, the sealing member arranged on the LED element side of the LED substrate, the warp prevention layer, and a diffusion prevention member.

[0268] The warp prevention layer used in this embodiment is the same as that described in the first embodiment of the surface emitting device. The LED substrate, the sealing member, and the anti-reflection member are the same as those described in the surface emitting device, so the description thereof will be omitted here.

[0269] 2. Second Aspect The sealing material sheet for a surface-emitting device of this embodiment is a sealing material sheet for a surface-emitting device used in a surface-emitting device, which is formed by laminating a sealing material for sealing an LED element and a foaming prevention layer arranged on one side of the sealing material, and has two forms: one in which the elastic modulus of the material constituting the foaming prevention layer is 500 MPa or more, and one in which the melting point of the material constituting the foaming prevention layer is 140°C or more.

[0270] The surface-emitting device is formed by laminating, in this order, a support substrate, an LED substrate having the LED element arranged on one side of the support substrate, the sealing member arranged on the LED element side of the LED substrate, the foaming prevention layer, and a diffusion prevention member.

[0271] The foaming prevention layer used in this embodiment is the same as that described in the third embodiment of the surface emitting device. The LED substrate, the sealing member, and the anti-reflection member are the same as those described in the surface emitting device, so that the description thereof is omitted here.

[0272] The present disclosure is not limited to the above-described embodiments. The above-described embodiments are merely examples, and anything that has substantially the same configuration as the technical idea described in the claims of the present disclosure and exhibits similar effects is included in the technical scope of the present disclosure. EXAMPLES

[0273] Hereinafter, experimental examples relating to a sealing member will be shown, followed by examples and comparative examples of the present disclosure, to explain the present disclosure in further detail.

[0274] A. Experimental Example (Experimental Example 1) As shown in Fig. 11, a surface emitting device 1 was manufactured having a supporting substrate 2, a light emitting diode substrate 4 having a light emitting diode element 3, a sealing member A (thickness 450 µm) 5, a diffusing member A 6, and a wavelength conversion member 9. The haze value, layer structure, density, and transmittance at a wavelength of 450 nm of the sealing member A are shown in Table 1. The evaluation results of brightness unevenness evaluated by the following method are shown in Table 2.

[0275] The materials used are as follows: Light emitting diode board The LED chips B0815ACQ0 (chip size 0.2 mm × 0.4 mm, manufactured by Genelights) were arranged in a square pattern with a 6 mm pitch on a supporting substrate (reflectivity 95%). Diffusion material A (diffusion plate) 55K3 (made by Entire) Wavelength conversion material (QD) QF-6000 (Showa Denko Materials)

[0276] The thickness of the sealing member and the optical properties shown in Table 1 are values ​​measured on the sealing member sample after sandwiching the sealing member sheet between ETFE films (thickness 100 μm) and performing heat treatment by vacuum lamination. The optical properties were measured by peeling off the ETFE film and measuring only the sealing member sample. The vacuum lamination conditions were as follows.

[0277] (Vacuum lamination conditions) (a) Vacuuming: 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℃

[0278] (Experimental Example 2) The occurrence of luminance unevenness was evaluated in the same manner as in Experimental Example 1, except that the following diffusing member B was used instead of the diffusing member A. The results are shown in Table 2. Diffusion material 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.

[0279] (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 sealing member B (thickness: 450 μm) shown in Table 1 was used instead of sealing member A.

[0280] (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 sealing member D (thickness: 450 μm) shown in Table 1 was used instead of sealing member A.

[0281] (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 a pin was provided between the diffusing member and the light-emitting diode substrate instead of the sealing member A. The results are shown in Table 2. In this case, the distance between the light-emitting diode element and the diffusing member was 500 μm.

[0282] (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 a Si cured material (thickness 450 μm) using a highly transparent potting-type liquid silicone composition was provided instead of the sealing material A. The results are shown in Table 2.

[0283] (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 sealing member C (thickness: 450 μm) shown in Table 1 was used instead of sealing member A. The results are shown in Table 2.

[0284] [Table 1]

[0285] [Luminance unevenness evaluation method] The brightness of the obtained surface emitting device was measured using a two-dimensional color luminance meter CA2000 when the LED was emitting light, and the brightness unevenness was evaluated. The brightness unevenness index was judged as follows based on the uniformity value.

[0286] [Evaluation Criteria] Uniformity = Minimum front luminance / Maximum front luminance A: Uniformity greater than 0.9 B: Uniformity 0.8 to 0.9 C: Uniformity smaller than 0.8

[0287] [Table 2]

[0288] The surface-emitting device of the present disclosure (Experimental Examples 1 to 6) was able to suppress the occurrence of brightness unevenness, whereas Comparative Experimental Examples 1 and 2, in which a pin was provided instead of sealing member A, Comparative Experimental Examples 3 and 4, in which a cured liquid Si product was used, and Comparative Experimental Examples 5 and 6, in which a sealing member C with a low haze value was used, were unable to suppress the occurrence of brightness unevenness.

[0289] B. Examples of the First and Second Embodiments Examples of the surface emitting devices of the first and second embodiments are given below.

[0290] [Example B-1] (Formation of Laminate of Sealing Member and Anti-Warp Layer) 100 parts by mass of the following base resin 1 was mixed with 5 parts by mass of additive resin 1 (weather resistance master batch) and 20 parts by mass of additive resin 2 (silane-modified polyethylene resin) to obtain a sealing member composition for molding a PET film-integrated sealing member material.

[0291] Base resin 1 Density 0.901g / cm 3 A metallocene-based linear low-density polyethylene resin (M-LLDPE) with a melting point of 93°C and an MFR of 2.0g / 10min at 190°C.

[0292] ·Additive resin 1 (weatherproofing masterbatch) Density 0.919g / cm 3 0.6 parts by mass of KEMISTAB62 (HALS) per 100 parts by mass of low-density polyethylene resin having a MFR of 3.5 g / 10 min at 190°C. Masterbatch containing 3.5 parts by mass of KEMISORB12 (UV absorbent) and 0.6 parts by mass of KEMISORB79 (UV absorbent).

[0293] Additive resin 2 (silane-modified polyethylene resin) Density 0.898g / cm 3 A silane-modified polyethylene resin was obtained by mixing 95 parts by mass of a metallocene-based linear low-density polyethylene resin having an MFR of 3.5 g / 10 min with 5 parts by mass of vinyltrimethoxysilane and 0.15 parts by mass of dicumyl peroxide as a radical generator (reaction catalyst), and melting and kneading the mixture at 200°C. The density of this additive resin 2 was 0.901 g / cm. 3 , MFR is 1.0g / 10min.

[0294] Next, a 50 μm-thick biaxially oriented polyethylene terephthalate film (optical grade) was used as an anti-warping layer, and this was integrated with the film onto which the above-mentioned sealing member composition had been melt-extruded by pressing to form an anti-warping layer laminate in which the anti-warping layer and a sealing member having a thickness of 300 μm were laminated.

[0295] Next, the above-mentioned warp prevention layer laminate was laminated onto the PCB substrate using a vacuum laminator. The PCB substrate was made by laminating white paint, copper, and glass epoxy in this order.

[0296] From the hot plate side of the vacuum laminator, the hot plate, Teflon (registered trademark) coated glass sheet 0.3 mm, glass (thickness 3 mm), release PET (release surface: upper), the PCB substrate with the glass epoxy surface on the release PET side, the warp prevention layer laminate with the sealing member on the PCB substrate side, release PET (release surface: lower), glass (thickness 3 mm), and Teflon (registered trademark) coated glass sheet 0.3 mm were laminated, and the lamination process was performed with a vacuum heating laminator under the processing conditions of 130 ° C. and 8 minutes as the vacuum laminator conditions. After lamination was completed, the 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. The sealing member laminate was regarded as a surface light-emitting device and various evaluations were performed.

[0297] [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 warp prevention layer was set to 100 μm.

[0298] [Example B-3] The same composition for sealing members as in Example B-1 and the same PCB substrate as in Example B-1 were used. First, a film of the above-mentioned sealing member composition melt-extruded to a thickness of 160 μm was adhered to the glass epoxy surface of the above-mentioned PCB member as an anti-warping layer, and then a film of the above-mentioned sealing member composition melt-extruded to a thickness of 240 μm was adhered to the white painted surface of the above-mentioned PCB member as a sealing member, thereby obtaining a sealing member laminate of the second embodiment.

[0299] [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 warp prevention layer was 80 μm.

[0300] [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 and the warp prevention layer were bonded together with a dry lamination adhesive. The main agent of the dry lamination adhesive was a polycarbonate urethane-based agent, and the hardener was an isocyanate-based hardener. The main agent and hardener were mixed at a ratio of 10:1, and the main agent and hardener were dissolved in a solvent and mixed at 50% by mass (ethyl acetate solution).

[0301] A two-liquid adhesive consisting of the above-mentioned base agent and curing agent was used to bond and laminate PET and a sheet-like sealing member using a laminator capable of dry lamination to produce a sealing member laminate for a backlight. A biaxially oriented polyethylene terephthalate film (optical grade) was used as the PET film, and this PET film was fed from the first feed side of the laminator, and the adhesive was dissolved in ethyl acetate as a solvent on the PET surface, gravure coating was performed so that the solid content coating amount was 2 to 15 g / m2 (film thickness after curing was 2 to 15 μm), and the solvent was evaporated and dried in a drying hood at about 70 to 90 °C to produce an adhesive surface. Thereafter, the sealing member was fed from the second feed, bonded with a nip roll, and laminated in a state of PET / adhesive / sealing member, and then wound up with a winding unit to produce a sealing member laminate. In addition, after producing the laminate roll, it was aged at 30 to 50 °C for about 70 to 200 hours to harden it.

[0302] [Comparative example B-1] A sealing member laminate was obtained in the same manner as in Example B-1, except that the warp prevention layer laminate was used as a sealing member having a thickness of 400 μm.

[0303] [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 warp prevention layer.

[0304] [Evaluation method] (Linear expansion coefficient) The dimensional change of a sheet cut to 5 mm x 20 mm was measured after heating according to JIS K7197 and cooling to room temperature, and the linear expansion coefficient was calculated by averaging from 100°C to 25°C. The linear expansion coefficient here is a positive value when contracting and a negative value when expanding. The measurement was performed using the following measuring device and under the following measuring conditions. Measurement equipment: Seiko Instruments Thermomechanical Apparatus (TMA / SS-6000) Constant load tension mode: 0.1mN Measurement temperature range: -50℃~160℃ -Temperature range for calculating linear expansion coefficient: 25℃~100℃

[0305] (Elasticity Modulus) The following tensile measurements were performed. (Measurement method) Measurement equipment: Instron universal material testing machine 5565 Load cell: 1kN Sample width: 10mm Chuck distance: 50mm ·Speed: 300mm / min

[0306] (Melting Point) The measurement was performed using a differential scanning calorimeter (DSC-60 Plus, manufactured by Shimadzu Corporation) according to the method of JIS K 7121.

[0307] (Total light transmittance) The measurement was performed according to a method conforming to JIS K7361-1:1997.

[0308] (Haze value) The haze was measured using a haze meter (HM-150, manufactured by Murakami Color Research Laboratory) according to the method of JIS K7136.

[0309] (Warpage) Immediately after vacuum lamination, each sealing member laminate was left to stand on a horizontal surface in a room temperature environment for 24 hours or more, after which the height from the horizontal surface of the corner to the underside of the substrate was measured using a steel straightedge conforming to JIS B 7514.

[0310] (Foaming 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 occurrence of bubbles was observed.

[0311] (Brightness Unevenness) A diffusion member was placed on the sealing member side of the sealing member laminate obtained in Examples B-1 to B-6 and Comparative Examples B-1 to B-2 to obtain the corresponding surface emitting devices. The measurement method and evaluation criteria for the luminance unevenness were the same as those shown in the above experimental examples. The diffusion member used was the same as the diffusion member B used in the above experimental example 2.

[0312] The results are shown in Table 3.

[0313] [Table 3]

[0314] C. Example of the Third Embodiment Next, an example of the surface light emitting device according to the third embodiment will be described.

[0315] [Example C-1] A sealing member laminate of the third embodiment was obtained in the same manner as in Example B-1, except that a biaxially stretched polyethylene terephthalate film (optical grade) having a thickness of 35 μm was used as the foaming prevention layer. The sealing member laminate was regarded as a surface emitting device and various evaluations were performed.

[0316] [Example C-2] A sealing member laminate was obtained in the same manner as in Example B-1 above, except that the warp prevention layer was used as the foaming prevention layer.

[0317] [Example C-3] A sealing member laminate was obtained in the same manner as in Example B-2 above, except that the warp prevention layer was used as the foaming prevention layer.

[0318] [Example C-4] A sealing member laminate was obtained in the same manner as in Example B-1 above, except that a random polypropylene having a thickness of 100 μm was used as the foaming prevention layer.

[0319] [Example C-5] A sealing member laminate was obtained in the same manner as in Comparative Example B-2, except that the warp prevention layer was used as the foaming prevention layer.

[0320] [Comparative example C-1] A sealing member laminate was obtained in the same manner as in Comparative Example B-1.

[0321] [Evaluation method] The elastic modulus, melting point, and foaming tests were carried out in the same manner as in "B. Examples of the first and second embodiments" above. The results are shown in Table 4.

[0322] [Table 4]

[0323] That is, the present disclosure provides the following inventions. [1] A sealing member sheet for a surface-emitting device, which is formed by laminating a sealing member for sealing a light-emitting diode element and a warp prevention layer disposed on one side of the sealing member, and is used in a surface-emitting device, wherein the linear expansion coefficient of a material constituting the warp prevention layer is less than or equal to -15×10 -6 / ℃ or more 10×10 -6 / °C or less. [2] The sealing member sheet for a surface-emitting device according to [1], wherein the sealing member has a thickness of 50 μm or more and 800 μm or less. [3] The sealing member sheet for a surface-emitting device according to [1] or [2], wherein the sealing member comprises a thermoplastic resin. [4] The sealing member has a density of 0.870 g / cm 3 More than 0.930g / cm 3 The sealing member sheet for a surface emitting device according to any one of [1] to [3], which has the following polyethylene resin as a base resin: [5] The sealing member sheet for a 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 surface side of the core layer. [6] The sealing member sheet for a surface-emitting device according to [5], wherein the core layer and the skin layer have thermoplastic resins contained as base resins with different melting points. [7] The sealing member sheet for a surface-emitting device according to [6] or [7], wherein the sealing member has a thermoplastic resin having a melting point of 90°C or more and 120°C or less as a base resin of the core layer. [8] The core layer of the sealing member has a density of 0.900 g / cm 3 More than 0.930g / cm 3 The following polyethylene resin is used as the base resin, and the skin layer has a density of 0.875 g / cm 3 More than 0.910g / cm 3 The sealing member sheet for a surface emitting device according to any one of [5] to [7] below, wherein the base resin is a polyethylene-based resin having a lower density than the base resin for the core layer. [9] A sealing material sheet for a surface-emitting device, which is formed by laminating a sealing material for sealing a light-emitting diode element and a foaming prevention layer arranged on one side of the sealing material, and is used in a surface-emitting device, wherein the elastic modulus of a material constituting the foaming prevention layer is 500 MPa or more.

[10] A sealing material sheet for a surface-emitting device, which is formed by laminating a sealing material for sealing a light-emitting diode element and a foaming prevention layer arranged on one side of the sealing material, and is used in a surface-emitting device, wherein the melting point of a material constituting the foaming prevention layer is 140°C or higher.

[11] A surface light emitting device comprising: a support substrate; a light emitting diode substrate having light emitting diode elements disposed on one surface of the support substrate; a sealing member disposed on a surface of the light emitting diode substrate facing the light emitting diode elements and sealing the light emitting diode elements; a warp prevention layer disposed on a surface of the sealing member opposite the light emitting diode substrate; and a diffusing member disposed on a surface of the warp prevention layer opposite the light emitting diode substrate, wherein the sealing member has a haze value of 4% or more and a thickness greater than a thickness of the light emitting diode elements, and a linear expansion coefficient of a material constituting the warp prevention layer is greater than or equal to -15×10 -6 / ℃ or more 10×10 -6 / ℃ or less.

[12] A surface-emitting device comprising: a supporting substrate; a light-emitting diode substrate having light-emitting diode elements arranged on one side of the supporting substrate; a sealing member arranged on a surface of the light-emitting diode substrate facing the light-emitting diode elements and sealing the light-emitting diode elements; a diffusing member arranged on a surface of the sealing member opposite the light-emitting diode substrate; and an anti-warping layer arranged on a surface of the light-emitting diode substrate opposite the light-emitting diode elements, wherein the sealing member has a haze value of 4% or more and a thickness greater than a thickness of the light-emitting diode elements, and the linear expansion coefficient of a material constituting the anti-warping layer is equal to or greater than the linear expansion coefficient of a material constituting 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 comprises a thermoplastic resin.

[15] The sealing member has a density of 0.870 g / cm 3 More than 0.930g / cm 3 A surface emitting device according to any one of

[11] to

[14] , which has the following polyethylene resin as a base resin:

[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 surface side of the core layer.

[17] The surface emitting device according to

[16] , wherein the core layer and the skin layer have thermoplastic resins contained as base resins with different melting points.

[18] The surface emitting device described in

[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 has a density of 0.900 g / cm 3 More than 0.930g / cm 3 The following polyethylene resin is used as the base resin, and the skin layer has a density of 0.875 g / cm 3 More than 0.910g / cm 3The surface emitting device according to any one of

[16] to

[18] below, wherein the base resin is a polyethylene-based resin having a lower density than the base resin for the core layer.

[20] A display device comprising a display panel and a surface emitting device according to any one of

[11] to

[19] , disposed on a rear surface of the display panel.

[21] A method for manufacturing a surface-emitting device as described in

[11] , comprising the steps of preparing a laminate in which the anti-warping layer, the sealing member, and the light-emitting diode substrate arranged in this order so that the light-emitting diode element faces the sealing member, and thermocompression bonding the laminate.

[22] A method for manufacturing a surface emitting device as described in

[11] , comprising the steps of: thermocompression bonding a first laminate in which the warp prevention layer and the sealing member are laminated; and thermocompression bonding a second laminate in which the light emitting diode substrate is arranged so that the light emitting diode element faces the sealing member, on the surface of the thermocompression bonded first laminate facing the sealing member. [Explanation of symbols]

[0324] 1, 10 ... Surface emitting device 2 … Support substrate 3. LED element 4 ... LED board 5 … Sealing member 6 … Diffusion material 7 … Anti-warping layer 100…Display device

Claims

1. a sealing member for sealing the light emitting diode element; A thermal expansion coefficient of the thermal expansion member is −10×10 －６ / ℃ or more 0×10 －６ / ° C. or less, and a warp prevention layer; having The sealing member has a haze value of 4% or more, The thickness of the sealing member is 50 μm or more and 800 μm or less, The sealing member is made of a polyolefin resin, A sealing member sheet for a surface-emitting device, wherein the linear expansion coefficient of the warp prevention layer is smaller than the linear expansion coefficient of the sealing member.

2. The sealing member has a density of 0.870 g / cm ３ 0.930g / cm or more ３ The sealing member sheet for a surface emitting device according to claim 1 , comprising the following polyethylene resin as a base resin:

3. 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 disposed on at least one surface side of the core layer.

4. The sealing member sheet for a surface emitting device according to claim 3 , wherein the core layer and the skin layer have thermoplastic resins contained as base resins with different melting points.

5. The sealing member sheet for a surface emitting device according to claim 4 , wherein the sealing member has a thermoplastic resin having a melting point of 90° C. or more and 120° C. or less as a base resin of the core layer.

6. The core layer of the sealing member has a density of 0.900 g / cm ３ 0.930g / cm or more ３ The following polyethylene resin is used as the base resin, and the skin layer has a density of 0.875 g / cm ３ 0.910g / cm or more ３ The sealing member sheet for a surface emitting device according to claim 3 , wherein the base resin is a polyethylene-based resin having a density lower than that of the base resin for the core layer.

7. The sealing member sheet for a surface emitting device according to claim 1 , wherein the sealing member is directly bonded to the warp prevention layer.

8. a light emitting diode substrate having a support substrate and a light emitting diode element disposed on one surface side of the support substrate; a sealing member disposed on a surface of the light emitting diode substrate facing 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; a diffusion member disposed on a surface of the warp prevention layer opposite to the light emitting diode substrate, The sealing member has a haze value of 4% or more, The thickness of the sealing member is 50 μm or more and 800 μm or less, The sealing member is made of a polyolefin resin, The linear expansion coefficient of the material constituting the warp prevention layer is −10×10 －６ / ℃ or more 0×10 －６ / ° C. or less, the linear expansion coefficient of the warp prevention layer is smaller than the linear expansion coefficient of the sealing member, A surface light emitting device, wherein the sealing member has a linear expansion coefficient greater than the linear expansion coefficient of the light emitting diode substrate.

9. The sealing member has a density of 0.870 g / cm ３ 0.930g / cm or more ３ 9. The surface emitting device according to claim 8, comprising the following polyethylene resin as a base resin:

10. The surface emitting device according to claim 8 , wherein the sealing member has a core layer and a skin layer disposed on at least one surface side of the core layer.

11. The surface emitting device according to claim 10 , wherein the core layer and the skin layer have thermoplastic resins contained as base resins with different melting points.

12. The surface emitting device according to claim 10 , wherein the sealing member contains a thermoplastic resin having a melting point of 90° C. or more and 120° C. or less as a base resin of the core layer.

13. The core layer of the sealing member has a density of 0.900 g / cm ３ 0.930g / cm or more ３ The following polyethylene resin is used as the base resin, and the skin layer has a density of 0.875 g / cm ３ 0.910g / cm or more ３ The surface emitting device according to claim 10 , wherein the base resin is a polyethylene-based resin having a density lower than that of the base resin for the core layer.

14. A display panel; A display device comprising the surface emitting device according to claim 8 arranged on a rear surface of the display panel.

15. A method for manufacturing the surface emitting device according to claim 8, comprising the steps of: A method for manufacturing a surface emitting device, comprising the steps of preparing a laminate in which the anti-warping layer, the sealing member, and the light emitting diode substrate arranged in this order so that the light emitting diode element faces the sealing member, and thermocompression bonding the laminate.

16. A method for manufacturing the surface emitting device according to claim 8, comprising the steps of: a step of thermocompression bonding a first laminate in which the warp prevention layer and the sealing member are laminated; a step of thermocompression bonding a second laminate in which the light emitting diode substrate is disposed on the surface of the thermocompression bonded first laminate facing the sealing member such that the light emitting diode element faces the sealing member; The method for manufacturing a surface emitting device comprising the steps of:

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