Light-emitting device, encapsulating sheet, surface light source device and liquid crystal display device

Abstract

To provide an encapsulating sheet for encapsulating a light-emitting element.SOLUTION: A light-emitting device 20 comprises a light-emitting substrate 30 and an encapsulating sheet 50 overlapped on the light-emitting substrate in a first direction. The light-emitting substrate comprises a wiring substrate 40 and a plurality of light-emitting elements 35 supported by the wiring substrate. The light-emitting elements are positioned between the wiring substrate and the encapsulating sheet. The encapsulating sheet comprises a light incident side surface and a light emission side surface 52 that face each other in the first direction. A light-emitting surface 36 comprises a light-emitting surface facing the light incident side surface 51. A ratio of a luminance at the light emission side surface above one light-emitting element to a luminance at the light-emitting surface of that one light-emitting element is 90% or more.SELECTED DRAWING: Figure 2A

Description

[Technical Field]

[0001] The present disclosure relates to a light-emitting device, an encapsulating sheet, a surface light source device, and a liquid crystal display device. [Background technology]

[0002] A light-emitting device including a light-emitting substrate is known. The light-emitting device disclosed in Patent Document 1 functions as a display device. Each light-emitting element functions as one pixel. The light-emitting element disclosed in Patent Document 2 constitutes a surface light source device having a light-emitting surface. The surface light source device may be a backlight for a liquid crystal display device.

[0003] The light-emitting substrate includes a wiring board and a plurality of light-emitting elements supported by the wiring board. The light-emitting elements may become unable to emit light stably due to contact with the outside or adhesion of moisture. Patent Documents 1 and 2 discuss the use of an encapsulating sheet for the purpose of protecting the light-emitting elements.

[0004] Patent document 1: WO2011 / 152314A1 Patent Document 2: WO2021 / 201164A1 DISCLOSURE OF THE INVENTION

[0005] The present disclosure aims to improve an encapsulating sheet used to encapsulate a light-emitting element.

[0006] A first light emitting device according to an embodiment of the present disclosure includes: A light-emitting substrate; a sealing sheet overlapping the light emitting substrate in a first direction, the light emitting substrate includes a wiring substrate and a plurality of light emitting elements supported by the wiring substrate; the light-emitting element is located between the wiring board and the sealing sheet, the encapsulating sheet includes a light-entering side surface and a light-emitting side surface facing each other in the first direction, the light-emitting element includes a light-emitting surface facing the light-incident side surface, The ratio of the luminance at the light-emitting side surface above one light-emitting element to the luminance at the light-emitting surface of the one light-emitting element is 90% or more.

[0007] A second light emitting device according to an embodiment of the present disclosure includes: A light-emitting substrate; a sealing sheet overlapping the light emitting substrate in a first direction, the light emitting substrate includes a wiring substrate and a plurality of light emitting elements supported by the wiring substrate; the light-emitting element is located between the wiring board and the sealing sheet, the encapsulating sheet includes a resin layer having an olefin-based resin as a base resin, The material constituting the resin layer has a residual crystallinity at 100° C. of 8.0 J / g or more.

[0008] A third light emitting device according to an embodiment of the present disclosure includes: A light-emitting substrate; a sealing sheet overlapping the light emitting substrate in a first direction, the light emitting substrate includes a wiring substrate and a plurality of light emitting elements supported by the wiring substrate; the light-emitting element is located between the wiring board and the sealing sheet, the encapsulating sheet includes a resin layer having a thermoplastic resin as a base resin and an inorganic oxide layer superimposed on the resin layer, The resin layer is located between the light emitting substrate and the inorganic oxide layer.

[0009] A first sealing sheet according to an embodiment of the present disclosure includes: It is used in any of the light emitting devices according to the embodiment of the present disclosure.

[0010] The second sealing sheet according to an embodiment of the present disclosure includes: An encapsulating sheet for encapsulating a light-emitting element, A resin layer having an olefin-based resin as a base resin is provided, The material constituting the resin layer has a residual crystallinity at 100° C. of 8.0 J / g or more.

[0011] A third sealing sheet according to an embodiment of the present disclosure includes: An encapsulating sheet for encapsulating a light-emitting element, a resin layer having a thermoplastic resin as a base resin; and an inorganic oxide layer superimposed on the resin layer.

[0012] A fourth encapsulating sheet according to an embodiment of the present disclosure includes: An encapsulating sheet for encapsulating a light-emitting element, Water vapor permeability is 0.3g / (m 2 24h or less.

[0013] A fifth encapsulating sheet according to an embodiment of the present disclosure includes: An encapsulating sheet for encapsulating a light-emitting element, Oxygen permeability is 0.3cc / (m 2 ·day·atm).

[0014] A surface light source device according to an embodiment of the present disclosure includes: The device includes any one of the light emitting devices according to an embodiment of the present disclosure.

[0015] A liquid crystal display device according to an embodiment of the present disclosure includes: a surface light source device according to any one of the embodiments of the present disclosure; The display device includes a display panel overlapped with the surface light source device.

[0016] According to the present disclosure, an encapsulating sheet for encapsulating a light-emitting element can be improved. [Brief explanation of the drawings]

[0017] [Figure 1] Fig. 1 is a perspective view showing a light emitting device for explaining one embodiment, and shows an example in which the light emitting device is applied to a dot matrix display device. [Figure 2A] FIG. 2A is a vertical cross-sectional view showing the light emitting device shown in FIG. [Figure 2B]FIG. 2B is a diagram corresponding to FIG. 2A, showing a modified example of the layer structure of the light-emitting device. [Figure 2C] FIG. 2C is a diagram corresponding to FIG. 2A, showing another modified example of the layer structure of the light emitting device. [Figure 2D] FIG. 2D is a view corresponding to FIG. 2A and shows a modified example of an encapsulating sheet that can be included in the light emitting device. [Figure 2E] FIG. 2E is a view corresponding to FIG. 2A and shows another modified example of the encapsulating sheet that can be included in the light emitting device. [Figure 2F] FIG. 2F is a view corresponding to FIG. 2A, showing yet another modified example of the encapsulating sheet that can be included in the light emitting device. [Figure 2G] FIG. 2G is a view corresponding to FIG. 2A, showing yet another modified example of the encapsulating sheet that can be included in the light emitting device. [Figure 2H] FIG. 2H is a view corresponding to FIG. 2A, showing yet another modified example of the encapsulating sheet that can be included in the light emitting device. [Figure 3] FIG. 3 is a plan view showing an example of a light emitting substrate that can be included in the light emitting device shown in FIG. [Figure 4] Fig. 4 is a diagram for explaining a method for manufacturing the light emitting device shown in Fig. 2A. Fig. 4 shows a step of integrating the encapsulating sheet with the light emitting substrate. [Figure 5] FIG. 5 is a diagram corresponding to FIG. 1, showing an example in which the light emitting device is applied to a surface light source device and a display device. [Figure 6] FIG. 6 is a vertical cross-sectional view showing the surface light source device and the display device shown in FIG. [Figure 7] FIG. 7 is a plan view showing an example of a light emitting substrate that can be included in the light emitting device shown in FIGS. [Figure 8A] FIG. 8A is a vertical cross-sectional view showing an example of an encapsulating sheet that can be applied to the light emitting device shown in FIG. 2D. [Figure 8B] FIG. 8B is a vertical cross-sectional view showing an example of an encapsulating sheet that can be applied to the light emitting device shown in FIG. 2E. [Figure 8C]FIG. 8C is a vertical cross-sectional view showing an example of an encapsulating sheet that can be applied to the light emitting device shown in FIG. 2F. [Figure 8D] Fig. 8D is a vertical cross-sectional view showing an example of an encapsulating sheet that can be applied to embodiment 2. Fig. 8D can be applied to the light emitting device shown in Fig. 2G. [Figure 8E] FIG. 8E is a vertical cross-sectional view showing an example of an encapsulating sheet that can be applied to the third embodiment. [Figure 8F] FIG. 8F is a vertical cross-sectional view showing another example of the encapsulating sheet that can be applied to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0018] One embodiment of the present disclosure is as follows. <1> ~ <37> Regarding.

[0019] <1> A light-emitting substrate; a sealing sheet overlapping the light emitting substrate in a first direction, the light emitting substrate includes a wiring substrate and a plurality of light emitting elements supported by the wiring substrate; the light-emitting element is located between the wiring board and the sealing sheet, the encapsulating sheet includes a light-entering side surface and a light-emitting side surface facing each other in the first direction, the light-emitting element includes a light-emitting surface facing the light-incident side surface, A light emitting device, wherein the ratio of the luminance at the light output side surface above one light emitting element to the luminance at the light emitting surface of the one light emitting element is 90% or more.

[0020] <2> The encapsulating sheet includes a resin layer having an olefin-based resin as a base resin. <1> The light emitting device according to claim 1.

[0021] <3> the residual crystallinity at 100°C of the resin material constituting the resin layer is 8.0 J / g or more; <2> The light emitting device according to claim 1.

[0022] <4> A light-emitting substrate; a sealing sheet overlapping the light emitting substrate in a first direction, the light emitting substrate includes a wiring substrate and a plurality of light emitting elements supported by the wiring substrate; the light-emitting element is located between the wiring board and the sealing sheet, the encapsulating sheet includes a resin layer having an olefin-based resin as a base resin, The light-emitting device has a residual crystallinity at 100° C. of the material that forms the resin layer of 8.0 J / g or more.

[0023] <5> The resin layer has a crosslinked structure. <3> or <4> The light emitting device according to claim 1.

[0024] <6> the encapsulating sheet includes a second resin layer superimposed on the resin layer, the resin layer is located between the light emitting substrate and the second resin layer, the melting point of the resin material constituting the second resin layer is higher than the melting point of the resin material constituting the resin layer; <3> ~ <5> 10. The light-emitting device according to claim 1 .

[0025] <7> The encapsulating sheet includes a light-shielding layer, the light-shielding layer is located between the light-emitting substrate and the resin layer, the light-shielding layer is located between the plurality of light-emitting elements; <2> ~ <6> 10. The light-emitting device according to claim 1 .

[0026] <8> the encapsulating sheet includes a reflective layer, the reflective layer is located between the light emitting substrate and the resin layer, The reflective layer is located between the plurality of light-emitting elements. <2> ~ <7> 10. The light-emitting device according to claim 1 .

[0027] <9> the encapsulating sheet includes a light-shielding layer located between the resin layer and the reflective layer, the light-shielding layer and the reflective layer are located between the plurality of light-emitting elements; <8> The light emitting device according to claim 1.

[0028] <10> the encapsulating sheet includes, in this order from the light-entering side surface to the light-emitting side surface, the resin layer and a patterned light-shielding layer, the patterned light-shielding layer includes an opening at a position above the light-emitting element; <2> ~ <9> 10. The light-emitting device according to claim 1,

[0029] <11> the wiring substrate includes a base material, a wiring layer, and a substrate light-shielding layer in this order in the first direction; the substrate light-shielding layer is located between the wiring layer and the sealing sheet; <2> ~ <10> 10. The light-emitting device according to claim 1,

[0030] <12> The resin layer has a transmission haze of 15% or less. <2> ~ <11> 10. The light-emitting device according to claim 1,

[0031] <13> The resin layer has a total light transmittance of 85% or more. <2> ~ <12> 10. The light-emitting device according to claim 1,

[0032] <14> The refractive index of the material constituting the resin layer is 1.41 or more and 1.58 or less. <2> ~ <13> 10. The light-emitting device according to claim 1,

[0033] <15> The melting point of the resin material constituting the resin layer is 50°C or higher and 145°C or lower. <2> ~ <14> 10. The light-emitting device according to claim 1,

[0034] <16> The melt mass flow rate of the material constituting the resin layer at a temperature of 190 ° C. is 0.50 g / 10 min or more and 40 g / 10 min or less. <2> ~ <15> 10. The light-emitting device according to claim 1,

[0035] <17> The density of the resin material constituting the resin layer is 0.875 g / cm 3 More than 0.930g / cm 3 Below is the <2> ~ <16> 10. The light-emitting device according to claim 1,

[0036] <18> the encapsulating sheet includes an inorganic oxide layer superimposed on the resin layer, the resin layer is located between the light emitting substrate and the inorganic oxide layer; <2> ~ <17> 10. The light-emitting device according to claim 1,

[0037] <19> A light-emitting substrate; a sealing sheet overlapping the light emitting substrate in a first direction, the light emitting substrate includes a wiring substrate and a plurality of light emitting elements supported by the wiring substrate; the light-emitting element is located between the wiring board and the sealing sheet, the encapsulating sheet includes a resin layer having an olefin-based resin as a base resin, and an inorganic oxide layer superimposed on the resin layer, The resin layer is located between the light emitting substrate and the inorganic oxide layer.

[0038] <20> the encapsulating sheet further includes a barrier resin layer located between the inorganic oxide layer and the resin layer, <18> or <19> The light emitting device according to claim 1.

[0039] <21> The water vapor permeability of the encapsulating sheet is 0.3 g / (m 2 24 hours or less, <18> ~ <20> 10. The light-emitting device according to claim 1,

[0040] <22> The oxygen permeability of the sealing sheet is 0.3 cc / (m 2 ·day·atm) or less, <18> ~ <21> 10. The light-emitting device according to claim 1,

[0041] <23> The resin layer contains an olefin-based resin as a base resin. <18> ~ <22> 10. The light-emitting device according to claim 1,

[0042] <24> The olefin-based resin includes one or more of polyethylene, polypropylene, cyclic olefin copolymer, and ethylene copolymer. <23> The light emitting device according to claim 1.

[0043] <25> The resin layer contains a biomass material. <18> ~ <24> 10. The light-emitting device according to claim 1,

[0044] <26> The inorganic oxide layer includes a vapor-deposited film containing one or more of silica, silicon oxide carbide, and alumina. <18> ~ <25> 10. The light-emitting device according to claim 1,

[0045] <27> the encapsulating sheet includes a support film superimposed on the inorganic oxide layer, the inorganic oxide layer is located between the support film and the resin layer, The support film comprises one or more of a polyolefin and a polyethylene terephthalate. <18> ~ <26> 10. The light-emitting device according to claim 1,

[0046] <28> The support film comprises a biomass material. <27> The light emitting device according to claim 1.

[0047] <29> <1> ~ <28> 10. An encapsulating sheet for use in the light emitting device according to any one of claims 1 to 9.

[0048] <30> An encapsulating sheet for encapsulating a light-emitting element, A resin layer having an olefin-based resin as a base resin is provided, The encapsulating sheet has a residual crystallinity at 100°C of the material constituting the resin layer of 8.0 J / g or more.

[0049] <31> An encapsulating sheet for encapsulating a light-emitting element, a resin layer having an olefin-based resin as a base resin; an inorganic oxide layer superimposed on the resin layer.

[0050] <32> Further comprising a barrier resin layer located between the inorganic oxide layer and the resin layer. <30> The encapsulating sheet according to claim 1.

[0051] <33> An encapsulating sheet for encapsulating a light-emitting element, Water vapor permeability is 0.3g / (m 2 24h) or less.

[0052] <34> An encapsulating sheet for encapsulating a light-emitting element, Oxygen permeability is 0.3cc / (m 2 An encapsulating sheet having a viscosity of less than 1000 kJ / day atm.

[0053] <35> The transmission haze is less than 8%. <31> ~ <34> The encapsulating sheet according to any one of the preceding claims.

[0054] <36> <1> ~ <28> 10. A surface light source device comprising the light emitting device according to any one of claims 1 to 9.

[0055] <37> <36> the surface light source device according to A liquid crystal display device comprising the surface light source device and a display panel superimposed thereon.

[0056] Hereinafter, several embodiments of the present disclosure will be described with reference to the drawings. Note that in the drawings attached to this specification, the scale and aspect ratios have been appropriately changed and exaggerated from those of the actual objects for the convenience of illustration and ease of understanding. Configurations shown in some drawings may be omitted in other drawings.

[0057] In this specification, terms that specify shapes, geometric conditions, and their degrees, such as "parallel," "orthogonal," and "identical," as well as values ​​of lengths and angles, are not limited to their strict meanings, but are interpreted to include a range within which similar functions can be expected.

[0058] In this specification, terms such as "sheet," "film," and "plate" are not distinguished from one another solely based on differences in name. For example, an "encapsulating sheet" cannot be distinguished from a member called a sealing film or a sealing plate solely based on differences in name.

[0059] In this specification, multiple upper limit candidates and multiple lower limit candidates for a numerical range may be described in separate sentences. In this description, the numerical range may be constructed by combining any one upper limit candidate with any one lower limit candidate. As an example, consider the following description: "Parameter B may be greater than or equal to A1, greater than or equal to A2, or greater than or equal to A3. Parameter B may be less than or equal to A4, less than or equal to A5, or less than or equal to A6." In this example, the numerical range of parameter B may be greater than or equal to A1 and less than or equal to A4, greater than or equal to A1 and less than or equal to A5, greater than or equal to A1 and less than or equal to A6, greater than or equal to A2 and less than or equal to A4, greater than or equal to A2 and less than or equal to A5, greater than or equal to A2 and less than or equal to A6, greater than or equal to A3 and less than or equal to A4, greater than or equal to A3 and less than or equal to A5, or greater than or equal to A3 and less than or equal to A6.

[0060] To clarify the relationship between directions between drawings, several drawings use arrows with common symbols to indicate a common first direction D1, second direction D2, and third direction D3. The tip of the arrow is the first side of each direction. The side opposite the tip of the arrow is the second side of each direction. An arrow pointing into the paper in a direction perpendicular to the paper surface of the drawing is indicated by a symbol with an x ​​in a circle, as shown in FIG. 2A, for example. An arrow pointing out of the paper in a direction perpendicular to the paper surface of the drawing is indicated by a symbol with a dot in a circle, as shown in FIG. 3, for example.

[0061] <<<Light-emitting device>>> In this embodiment, the light emitting device 20 is a device that emits light. As shown in FIGS. 1 and 2A, in this embodiment, the light emitting device 20 includes a light emitting substrate 30 and an encapsulating sheet 50. The light emitting substrate 30 and the encapsulating sheet 50 may be stacked in a first direction D1. The light emitting substrate 30 may include a wiring substrate 40 and a plurality of light emitting elements 35. As shown in FIGS. 2A and 3, the plurality of light emitting elements 35 may be supported by the wiring substrate 40. The plurality of light emitting elements 35 may be positioned between the wiring substrate 40 and the encapsulating sheet 50 in the first direction D1.

[0062] The light-emitting element 35 emits light. The light emitted from the light-emitting element 35 travels to the first side in the first direction D1. The light emitted from the light-emitting element 35 passes through the encapsulating sheet 50 and is emitted from the light-emitting device 20. The light-emitting device 20 functions as a display device 10, for example. One light-emitting element 35 may constitute one pixel in the display device 10. The statement that one light-emitting element 35 constitutes one pixel means that, when one pixel is constituted by multiple subpixels, one light-emitting element 35 constitutes one subpixel. In other words, the statement that one light-emitting element 35 constitutes one pixel can be interpreted as one light-emitting element 35 constitutes one pixel or one subpixel.

[0063] The encapsulating sheet 50 covers the light-emitting element 35 from the first side in the first direction D1, in other words, from the viewer side. The encapsulating sheet 50 can prevent the light-emitting element 35 from coming into contact with the outside. That is, the encapsulating sheet 50 can prevent the light-emitting element 35 from being damaged by contact with the outside or by external impact. The encapsulating sheet 50 can prevent the light-emitting element 35 from coming into contact with moisture. That is, the encapsulating sheet 50 can prevent the light-emitting element 35, which is an electronic device, from malfunctioning or deteriorating due to contact with moisture. The encapsulating sheet 50 can prevent the light-emitting element 35 from coming into contact with oxygen. That is, the encapsulating sheet 50 can prevent the light-emitting element 35 from deteriorating due to oxidation.

[0064] The encapsulating sheet 50 is useful for protecting the light emitting element 35. However, conventional encapsulating sheets have not been sufficient. As will be described later, the encapsulating sheet 50 according to the present embodiment is superior to conventional encapsulating sheets. The encapsulating sheet 50 according to the present embodiment can suppress the defects associated with conventional encapsulating sheets. Hereinafter, first to third aspects related to the light emitting device 20 and the encapsulating sheet 50 will be described.

[0065] According to the first aspect, by improving the encapsulating sheet, it is possible to improve the light emitting characteristics of the light emitting device 20. According to the first aspect, for example, in an example where the light emitting device 20 constitutes a dot matrix type display device 10, it is possible to suppress color mixing of light from each light emitting element 35 constituting a pixel. According to the first aspect, it is possible to display an image with excellent visibility.

[0066] According to the second aspect, the generation of bubbles between the light emitting substrate 30 and the sealing sheet 50 and inside the sealing sheet 50 can be suppressed.

[0067] According to the third aspect, it is possible to suppress deterioration of the light emitting element 35, which is an electronic device, due to moisture, oxygen, and the like.

[0068] Hereinafter, the light emitting device 20 will be described in further detail with reference to the illustrated specific examples. First, the configuration, use, and effects of the light emitting device 20 will be described, and then first to third aspects relating to the improvements to the light emitting device 20 and the encapsulating sheet 50 will be described in order.

[0069] The light emitting device 20 may include any other functional layers in addition to the light emitting substrate 30 and the encapsulating sheet 50. In the example shown in Figures 1 and 2A, the light emitting device 20 further includes a transparent plate 28. In the illustrated example, the encapsulating sheet 50 is located between the light emitting substrate 30 and the transparent plate 28 in the first direction D1.

[0070] <<Transparent plate>> The transparent plate 28 may cover the sealing sheet 50 from the first side in the first direction D1, i.e., the viewer side. The transparent plate 28 may protect the sealing sheet 50. The transparent plate 28 may be transparent. Light emitted from the light-emitting substrate 30 can pass through the transparent plate 28. The material of the transparent plate 28 may be resin or glass.

[0071] The transparent plate 28 is not limited to a flat layer. The transparent plate 28 may include an optical element such as a lens. The transparent plate 28 may include an optical element surface including a lens or the like. By including a lens or the like in the transparent plate 28, directivity may be imparted to the traveling direction of light that has passed through the transparent plate 28.

[0072] In this specification, "transparent" means that the total light transmittance is 50% or more. The total light transmittance of a transparent member may be 70% or more, 80% or more, or 90% or more. There is no particular upper limit set for the total light transmittance of a transparent member. The total light transmittance of a transparent member may be 100% or less, or may be less than 100%.

[0073] A D65 light source is used to measure total luminous transmittance. The wavelength range of light used to measure total luminous transmittance (%) is 380 nm or more and 780 nm or less. Before measuring the total luminous transmittance of the sample, turn on the D65 light source for 15 minutes to stabilize the output of the D65 light source. The angle of incidence on the sample when measuring total luminous transmittance is 0°. The test environment when measuring total luminous transmittance is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The sample is left in the test environment for 16 hours before starting the test. Other measurement conditions when measuring total luminous transmittance are in accordance with JIS K7361-1:1997.

[0074] <<Light-emitting substrate>> The light emitting substrate 30 may include a wiring substrate 40 and a plurality of light emitting elements 35. As shown in FIGS. 2A and 3, the wiring substrate 40 may support the plurality of light emitting elements 35. The wiring substrate 40 may be capable of supplying electricity to each of the light emitting elements 35. The plurality of light emitting elements 35 may be fixed to the wiring substrate 40 by solder or the like. The plurality of light emitting elements 35 may be electrically connected to the wiring substrate 40 by solder or the like.

[0075] <Wiring board> 2A, the wiring board 40 may include a base material 41 and a wiring layer 42. The wiring board 40 may be a so-called circuit board.

[0076] The wiring layer 42 may include wiring 42X formed from a conductive material. The conductive material may be one or more of copper, aluminum, silver, alloys thereof, etc. The conductive material may be a transparent conductive material or a conductive polymer. Examples of transparent conductive materials include indium tin oxide (ITO) and zinc oxide (ZnO). Examples of conductive polymers include graphene. The wiring layer 42 may be supported by the substrate 41. The wiring layer 42 may be formed on the substrate 41 by printing or the like.

[0077] The substrate 41 may be a hard substrate or a bendable soft substrate. The hard substrate 41 may be a glass substrate containing glass, a semiconductor material containing silicon (Si) or the like, or a resin substrate containing resin. The soft substrate 41 may be a resin substrate containing resin. The resin contained in the resin substrate may be one or more of polyethylene terephthalate, polyethylene naphthalate, and polyimide.

[0078] The wiring substrate 40 may include layers other than the base material 41 and the wiring layer 42. As shown in Fig. 2B, the wiring substrate 40 may include a substrate light-shielding layer 43. In the example shown in Fig. 2B, the wiring substrate 40 includes the substrate light-shielding layer 43, the wiring layer 42, and the base material 41 in this order from the first side to the second side in the first direction D1, i.e., in this order away from the encapsulating sheet 50 in the first direction D1.

[0079] The substrate light-shielding layer 43 has light-shielding properties. The total light transmittance of the substrate light-shielding layer 43 having light-shielding properties may be 40% or less, 30% or less, 10% or less, or 5% or less. There is no particular lower limit set for the total light transmittance of the substrate light-shielding layer 43. The total light transmittance of the substrate light-shielding layer 43 may be 0% or more, or may be greater than 0%.

[0080] The substrate light-shielding layer 43 may at least partially constitute the surface of the wiring substrate 40 facing the first side in the first direction D1. The substrate light-shielding layer 43 may constitute the entire area of ​​the surface of the wiring substrate 40 facing the first side in the first direction D1. The substrate light-shielding layer 43 may constitute the entire area of ​​the surface of the wiring substrate 40 facing the first side in the first direction D1 except for the area where the light-emitting elements 35 are arranged. The substrate light-shielding layer 43 may cover the wiring 42X of the wiring layer 42 from the first side in the first direction D1.

[0081] The wiring layer 42 has high reflectivity. When the light-emitting device 20 constitutes a dot-matrix display device 10, external light may be reflected by the wiring 42X. The reflection of external light by the wiring 42X deteriorates the contrast of the image displayed by the display device 10. The substrate light-shielding layer 43 can suppress reflection by the wiring layer 42, thereby improving the contrast of the image displayed by the light-emitting device 20.

[0082] The substrate light-shielding layer 43 may be a layer containing a pigment. The substrate light-shielding layer 43 may include a binder resin portion and a pigment dispersed in the binder resin portion. The pigment may be a black pigment such as carbon black or titanium black. The substrate light-shielding layer 43 may include multiple types of color pigments. The substrate light-shielding layer 43 may include one or more of a blue pigment, a green pigment, a red pigment, and a yellow pigment as the color pigment.

[0083] <Light-emitting element> The light-emitting element 35 emits light. The light-emitting element 35 includes a light-emitting surface 36. Light is emitted from the light-emitting surface 36. The light-emitting element 35 may be a light-emitting diode, also referred to as an LED (Light Emitting Diode). The light-emitting element 35 may be a small light-emitting diode, such as a mini LED or a micro LED. The light-emitting element 35 may be an organic light-emitting diode, also referred to as an OLED (Organic Light Emitting Diode), or an organic EL (Organic Electro-Luminescence).

[0084] The shape and dimensions of the light-emitting element 35 are not particularly limited. When viewed from the first direction D1 shown in FIG. 3, the light-emitting element 35 has a rectangular shape. The lengths WL1 and WL2 of each side of the light-emitting element 35 may be 0.005 mm or more, 0.01 mm or more, or 0.05 mm or more. The lengths WL1 and WL2 of each side of the light-emitting element 35 may be 0.5 mm or less, 0.2 mm or less, or 0.1 mm or less. As shown in FIG. 2A, the thickness TL of the light-emitting element 35 may be 0.0001 mm or more, 0.001 mm or more, or 0.01 mm or more. The thickness TL of the light-emitting element 35 may be 0.5 mm or less, 0.1 mm or less, or 0.01 mm or less. In the illustrated example, the thickness TL of the light-emitting element 35 is the length of the light-emitting element 35 protruding from the wiring substrate 40 in the first direction D1.

[0085] The emission wavelength of the light-emitting element 35 may be appropriately selected depending on the application of the light-emitting device 20. The emission wavelength of the light-emitting element 35 may be within the visible light wavelength range or may be outside the visible light wavelength range, such as ultraviolet light. The visible light wavelength range is 380 nm to 780 nm. The wavelength range of light emitted from the light-emitting element 35 may be converted by a color conversion agent such as quantum dots. The multiple light-emitting elements 35 may include a single type of light-emitting element that emits blue light or green light. The multiple light-emitting elements 35 may include multiple types of light-emitting elements that emit light in different wavelength ranges. The multiple light-emitting elements 35 may include a light-emitting element that emits blue light and a light-emitting element that emits yellow light. The light-emitting elements 35 may include a light-emitting element that emits blue light, a light-emitting element that emits green light, and a light-emitting element that emits red light. Dimensions, such as the above-mentioned lengths WL1 and WL2 and thickness TL, may be different among the multiple types of light-emitting elements that emit light in different wavelength ranges.

[0086] The light distribution characteristic of the light-emitting element 35 is not particularly limited. The light distribution characteristic of the light-emitting element 35 may be a Lambertian light distribution. In the emission luminous intensity distribution of the light-emitting element 35 whose optical axis is aligned in the first direction D1, a peak luminous intensity may be obtained in a direction other than the first direction D1. For example, the light-emitting element 35 may have a bad wing light distribution as disclosed in JP6299811B.

[0087] As an example, the light-emitting element 35 may be composed of only a light-emitting element. As shown by the two-dot chain line in FIG. 2A, the light-emitting element 35 may include a light-emitting element body 35A such as an LED and a cover 35B that covers the light-emitting element body 35A. The cover 35B forms the light-emitting surface 36 of the light-emitting element 35. The cover 35B may adjust the light distribution from the light-emitting element. The cover 35B may have a lens function or a prism function. The cover 35B may include a reflective film that partially covers the light-emitting element body 35A. By using the cover 35B as a partial reflective film, a bad-wing light distribution may be achieved. The cover 35B may include a color conversion agent such as quantum dots.

[0088] The light emitting device 20 includes a plurality of light emitting elements 35. The number of light emitting elements 35 is appropriately selected depending on the application and size of the light emitting device 20, etc. The plurality of light emitting elements 35 may be two-dimensionally arranged on a plane perpendicular to the first direction D1. A two-dimensional arrangement means that objects such as the light emitting elements 35 are arranged in two or more non-parallel directions. The plurality of light emitting elements 35 may be arranged regularly. Examples of regular arrangements of the light emitting elements 35 include a honeycomb arrangement and a square arrangement. In a honeycomb arrangement, the light emitting elements 35 may be arranged at a constant pitch in each of three directions inclined at 60° to each other. As shown in FIG. 3, in a square arrangement, the light emitting elements 35 may be arranged at a constant pitch in each of two directions perpendicular to each other.

[0089] As shown in FIG. 3, the plurality of light-emitting elements 35 may be arranged at a constant pitch in each of the second direction D2 and the third direction D3, which are perpendicular to each other. The arrangement pitch PL1 of the light-emitting elements 35 in the second direction D2 and the arrangement pitch PL2 of the light-emitting elements 35 in the third direction D3 may be the same. The arrangement pitch PL1 and the arrangement pitch PL2 may be different. The second direction D2 and the third direction D3 may be parallel to the side edges of the rectangular light-emitting device 20. The arrangement pitch PL1 and the arrangement pitch PL2 may be 0.001 mm or more, 0.01 mm or more, or 0.1 mm or more. The arrangement pitch PL1 and the arrangement pitch PL2 may be 10 mm or less, 1 mm or less, or 0.5 mm or less.

[0090] The first direction D1 is parallel to the direction in which the light emitting substrate 30, the sealing sheet 50, and the transparent plate 28 are stacked. In the illustrated example, the light emitting substrate 30, the sealing sheet 50, and the transparent plate 28 extend on a plane perpendicular to the first direction D1. In the illustrated example, the light emitting substrate 30, the sealing sheet 50, and the transparent plate 28 extend in the second direction D2 and the third direction D3. The portions 41, 42, and 43 included in the wiring board 40 of the light emitting substrate 30 are stacked in the first direction D1. The portions 41, 42, and 43 included in the wiring board 40 of the light emitting substrate 30 extend in the second direction D2 and the third direction D3. The portions 60, 60A, 60B, 60C, 65, 66, and 67 included in the sealing sheet 50 (described later) are stacked in the first direction D1. The portions 60, 60A, 60B, 60C, 65, 66, and 67 included in the encapsulating sheet 50 extend in the second direction D2 and the third direction D3.

[0091] <<Sealing sheet>> The encapsulating sheet 50 is located between the light-emitting substrate 30 and the transparent plate 28 in the first direction D1. The encapsulating sheet 50 includes a light-entering side surface 51 and a light-exiting side surface 52 that face each other in the first direction D1. The light-entering side surface 51 faces a second side in the first direction D1. The light-entering side surface 51 faces the light-emitting substrate 30. The light-emitting element 35 faces the light-entering side surface 51. The light-exiting side surface 52 faces a first side, which is the viewer side, in the first direction D1. The light-exiting side surface 52 faces the transparent plate 28.

[0092] The encapsulating sheet 50 may be in contact with the light emitting substrate 30 at the light incident side surface 51. The encapsulating sheet 50 may be bonded to the light emitting substrate 30 at the light incident side surface 51. The encapsulating sheet 50 may be in contact with the wiring substrate 40 at the light incident side surface 51. The encapsulating sheet 50 may be bonded to the wiring substrate 40 at the light incident side surface 51.

[0093] The encapsulating sheet 50 may include a resin layer 60 containing an olefin-based resin. As shown in FIG. 2A , the encapsulating sheet 50 may be composed of only the resin layer 60. In other words, the encapsulating sheet 50 may be the resin layer 60. In the example shown in FIG. 2A , the light-incident side surface 51 is composed of the resin layer 60. The light-emitting side surface 52 is composed of the resin layer 60.

[0094] The encapsulating sheet 50 may cover the plurality of light-emitting elements 35. The encapsulating sheet 50 may protect the light-emitting elements 35 by covering them. The encapsulating sheet 50 may suppress contact of water vapor or moisture with the light-emitting elements 35 by covering the light-emitting elements 35. The encapsulating sheet 50 may protect the wiring layer 42 by covering it. The encapsulating sheet 50 may suppress contact of water vapor or moisture with the wiring layer 42 by covering it. The encapsulating sheet 50 may suppress oxidation of the wiring layer 42 by covering it.

[0095] In an example in which the encapsulating sheet 50 includes the resin layer 60, the light emitting substrate 30, the encapsulating sheet 50, and the transparent plate 28 may be bonded together by heating and pressing, as shown in Fig. 4. The heating and pressing step may be performed under reduced pressure or in vacuum.

[0096] The light emitting substrate 30 may be pressed against the encapsulating sheet 50 in a heated state, thereby welding the encapsulating sheet 50 or the resin layer 60 to the light emitting substrate 30. That is, the light emitting substrate 30 and the encapsulating sheet 50 may be integrated with each other by being pressed toward each other in a heated state. At this time, the light emitting element 35 protruding from the wiring substrate 40 may be buried in the encapsulating sheet 50 or the resin layer 60, as shown in FIG. 2A .

[0097] In a heated state, the transparent plate 28 may be pressed against the sealing sheet 50, thereby welding the sealing sheet 50 and the resin layer 60 to the transparent plate 28. That is, in a heated state, the transparent plate 28 and the sealing sheet 50 may be pressed toward each other, thereby integrating the transparent plate 28 and the sealing sheet 50.

[0098] As indicated by the two-dot chain line in Figure 4, the resin layer 60 may include a first portion 60A, a second portion 60B, and a third portion 60C. The first portion 60A and the third portion 60C form skin layers. The first portion 60A and the third portion 60C form the outermost layers in the first direction D1, which is the thickness direction. The second portion 60B forms a core layer. The second portion 60B is located between the first portion 60A and the third portion 60C in the first direction D1, which is the thickness direction.

[0099] The first portion 60A and the third portion 60C may have a composition that makes them more likely to weld to the adjacent layers than the second portion 60B. In the example in which the heat and pressure process shown in Fig. 4 is applied, the first portion 60A and the third portion 60C are more likely to be joined to the adjacent layers by welding.

[0100] The thickness T50 of the encapsulating sheet 50 and the thickness T60 of the resin layer 60, i.e., the length in the first direction D1, may be greater than 0 μm, 20 μm or more, 30 μm or more, 40 μm or more, 50 μm or more, or 70 μm or more. The thickness T50 of the encapsulating sheet 50 and the thickness T60 of the resin layer 60, i.e., the length in the first direction D1, may be 300 μm or less, 150 μm or less, 100 μm or less, 90 μm or less, or 80 μm or less.

[0101] In an example in which the encapsulating sheet 50 is integrated with the light emitting substrate 30 by heating and pressing, as will be described later with reference to Fig. 4, the thickness T50 of the encapsulating sheet 50 and the thickness T60 of the resin layer 60 before the heating and pressing treatment may be in the following ranges. The thickness T50 of the encapsulating sheet 50 and the thickness T60 of the resin layer 60 before the heating and pressing treatment may be greater than 0 µm, may be 20 µm or more, may be 30 µm or more, may be 40 µm or more, may be 50 µm or more, or may be 70 µm or more. The thickness T50 of the encapsulating sheet 50 and the thickness T60 of the resin layer 60 before the heating and pressing treatment may be 300 µm or less, may be 150 µm or less, may be 100 µm or less, may be 90 µm or less, or may be 80 µm or less.

[0102] 2A , the thickness T50 of the encapsulating sheet 50 and the thickness T60 of the resin layer 60 are measured on the light emitting element 35. That is, the thickness T50 of the encapsulating sheet 50 corresponds to the length along the first direction D1 between the light incident side surface 51 and the light emitting side surface 52 on the light emitting element 35.

[0103] By setting the above-mentioned lower limits for the thickness T50 of the encapsulating sheet 50 and the thickness T60 of the resin layer 60, it is possible to sufficiently prevent damage to the light emitting element 35 due to contact with the outside. In other words, it is possible to provide the encapsulating sheet 50 and the resin layer 60 with a sufficient protective function.

[0104] When the thickness T50 of the sealing sheet 50 and the thickness T60 of the resin layer 60 are set to 10 μm or less, the transparent plate 28 may be provided. The transparent plate 28 can effectively protect the light emitting element 35.

[0105] By setting the thickness T50 of the encapsulating sheet 50 and the thickness T60 of the resin layer 60 to be greater than 0 μm and equal to or less than the above-mentioned upper limit, it is possible to suppress blocking of light from the light-emitting element 35 and obtain high brightness on the light-emitting side surface 52. In particular, in an example in which the encapsulating sheet 50 includes a light-shielding layer 66, a reflective layer 67, or a patterned light-shielding layer 68, which will be described later, it is possible to obtain high brightness on the light-emitting side surface 52.

[0106] By setting the above upper limits for the thickness of the encapsulating sheet 50 and the thickness of the resin layer 60, the transmittance of the encapsulating sheet 50 can be made sufficiently large. By setting the above upper limits for the thickness T50 of the encapsulating sheet 50 and the thickness T60 of the resin layer 60, the resin layer 60 can be given sufficient formability. More specifically, the resin constituting the resin layer 60 can be sufficiently deformed to conform to the irregularities on the surface of the light emitting substrate 30 from which the light emitting elements 35 protrude. Formation of a gap between the resin layer 60 and the light emitting substrate 30 can be suppressed. Formation of a gap between the resin layer 60 and the light emitting surface 36 of the light emitting element 35 can be suppressed.

[0107] The total light transmittance of the encapsulating sheet 50 and the total light transmittance of the resin layer 60 may be 85% or more, 90% or more, or 95% or more. By setting a lower limit for the total light transmittance of the encapsulating sheet 50 and the total light transmittance of the resin layer 60, the utilization efficiency of the light emitted from the light emitting element 35 can be maintained high.

[0108] There is no particular upper limit set for the total light transmittance of the encapsulating sheet 50 and the total light transmittance of the resin layer 60. The total light transmittance of the encapsulating sheet 50 and the total light transmittance of the resin layer 60 may be 100% or less, or may be less than 100%.

[0109] The transmission haze of the encapsulating sheet 50 and the transmission haze of the resin layer 60 may be 15% or less, 8% or less, or 5% or less. By setting upper limits for the transmission haze of the encapsulating sheet 50 and the transmission haze of the resin layer 60, an image with excellent visibility can be displayed in the light-emitting device 20 constituting the dot-matrix display device 10. The value of the transmission haze described here is the value of the transmission haze of the encapsulating sheet 50 measured in an area where the light-shielding layer 66, the reflective layer 67, and the patterned light-shielding layer 68 are not provided, in an example in which the encapsulating sheet 50 includes a light-shielding layer 66, a reflective layer 67, a patterned light-shielding layer 68, etc., which will be described later.

[0110] There is no particular lower limit set for the transmission haze of the encapsulating sheet 50 and the transmission haze of the resin layer 60. The transmission haze of the encapsulating sheet 50 and the transmission haze of the resin layer 60 may be 0% or more, or may be more than 0%.

[0111] A D65 light source is used to measure transmission haze. The wavelength range of light used to measure transmission haze (%) is 380 nm to 780 nm. Before measuring the transmission haze of the sample, the D65 light source is turned on for 15 minutes to stabilize the output of the D65 light source. The angle of incidence on the sample when measuring transmission haze is 0°. The test environment for measuring transmission haze is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The sample is left in the test environment for 16 hours before starting the test. Other measurement conditions for measuring transmission haze are in accordance with JIS K7136:2000.

[0112] In an example where the resin layer 60 is in contact with the light-emitting surface 36 of the light-emitting element 35 as shown in FIG. 2A etc., a lower limit and an upper limit may be set for the refractive index of the material constituting the resin layer 60. The refractive index of the material constituting the resin layer 60 may be 1.41 or more, 1.45 or more, or 1.48 or more. The refractive index of the material constituting the resin layer 60 may be 1.58 or less, 1.55 or less, or 1.52 or less. By setting the numerical range of the refractive index of the material constituting the resin layer 60, it is possible to suppress diffusion of light from the light-emitting element 35 at the interface between the light-emitting element 35 and the resin layer 60. In the light-emitting device 20 constituting the dot-matrix display device 10, it is possible to display images with excellent visibility.

[0113] The refractive index of the material that makes up the resin layer is measured in accordance with Method A of JIS K7142:2014. The light used for the measurement is the D-line (wavelength 589 nm). An Abbe refractometer is used for the measurement. The Abbe refractometer used is the "Abbe refractometer D-M2" manufactured by Atago Co., Ltd.

[0114] In an example where the resin layer 60 is in contact with the light-emitting surface 36 of the light-emitting element 35 as shown in FIG. 2A etc., an upper and lower limit may be set for the melt mass flow rate (MFR) at 190°C of the material constituting the resin layer 60. The melt mass flow rate (MFR) at 190°C of the material constituting the resin layer 60 may be 0.50 g / 10 min or more, 1.0 g / 10 min or more, or 3.0 g / 10 min or more. The melt mass flow rate (MFR) at 190°C of the material constituting the resin layer 60 may be 40 g / 10 min or less, 20 g / 10 min or less, or 10 g / 10 min or less.

[0115] By setting a lower limit for the melt mass flow rate at 190°C of the material constituting the resin layer 60, it is possible to impart sufficient formability to the resin layer 60. More specifically, the resin constituting the resin layer 60 can be sufficiently deformed to conform to the irregularities on the surface of the light emitting substrate 30 from which the light emitting elements 35 protrude. It is possible to prevent voids from being formed between the resin layer 60 and the light emitting substrate 30. It is possible to prevent voids from being formed between the resin layer 60 and the light emitting surface 36 of the light emitting element 35. It is possible to prevent voids from being visible. It is possible to prevent unintended light diffusion due to voids. In the light emitting device 20 constituting the dot matrix display device 10, it is possible to display images with excellent visibility.

[0116] By setting an upper limit to the melt mass flow rate at 190°C of the material constituting the resin layer 60, the fluidity of the resin layer 60 can be limited. This allows the resin layer 60 to be processed stably and easily, such as through a heating and pressurizing process. The occurrence of unintended irregularities on the surface of the resin layer 60 can be suppressed.

[0117] By setting an upper limit to the melt mass flow rate at 190°C of the material constituting the resin layer 60, it is possible to suppress in-plane variations in the thickness of the resin layer 60 that is heated and pressed toward the light emitting substrate 30. In an example in which the light emitting device 20 constitutes a dot matrix type display device 10, if the thickness of the encapsulating sheet 50 varies greatly in-plane, the propagation directions of light emitted from the plurality of light emitting elements 35 may be unintentionally bent in different directions from each other. This may cause in-plane variations in the brightness of the observed image. From this perspective, the light emitting device 20 constituting the dot matrix type display device 10 can display images with excellent visibility.

[0118] The melt mass flow rate of the material constituting the resin layer 60 is measured on a sample formed into a sheet. In an example where the resin layer 60 includes a resin portion and an additive dispersed within the resin portion, a sample containing the additive is used to measure the melt mass flow rate. The melt mass flow rate is measured at 190°C under a load of 2.16 kg. Other measurement conditions for the melt mass flow rate follow Method A of JIS K7210-1:2014. In an example where the resin layer 60 includes multiple layers, a sample in which all layers are laminated is measured.

[0119] In an example where the resin layer 60 is in contact with the light-emitting surface 36 of the light-emitting element 35 as shown in FIG. 2A etc., an upper and lower limit may be set for the melting point of the resin material that constitutes the resin layer 60. The melting point of the resin material that constitutes the resin layer 60 may be 50°C or higher, 70°C or higher, or 90°C or higher. The melting point of the resin material that constitutes the resin layer 60 may be 145°C or lower, 135°C or lower, or 110°C or lower.

[0120] By setting an upper limit to the density of the resin material constituting the resin layer 60, it is possible to impart sufficient moldability to the resin layer 60. It is possible to suppress in-plane variations in the thickness of the resin layer 60 that is heated and pressurized toward the light-emitting substrate 30. As a result, it is possible to suppress the visibility of voids. It is possible to suppress unintended light diffusion due to voids. In the light-emitting device 20 constituting the dot-matrix display device 10, it is possible to display images with excellent visibility.

[0121] By setting a lower limit for the melting point of the resin material that constitutes the resin layer 60, the fluidity of the resin layer 60 can be limited. This makes it possible to prevent the resin layer 60 from melting and deforming when the light emitting device 20 is in use. Processing of the resin layer 60, such as a heating and pressurizing process, can be stably and easily carried out. It is possible to prevent unintended irregularities from occurring on the surface of the resin layer 60.

[0122] The melting point of a resin material is the "melting peak temperature" specified in JIS K7121:2012. The melting peak temperature is determined using a differential scanning calorimetry (DSC) curve. The DSC curve shows the change in endothermic heat from the heating start temperature to the heating end temperature. The heating start temperature is 0°C. The area surrounding the sample to be evaluated is maintained at the heating start temperature, and the sample temperature is lowered to the heating start temperature. The heating rate is 10°C per minute. The heating end temperature is 200°C. In other words, the endothermic heat is measured while heating from 0°C to 200°C at a rate of 10°C per minute. The "melting peak temperature" as the melting point of a resin material is the temperature at which the endothermic heat peak occurs in the DSC curve. If the DSC curve contains multiple endothermic peaks, the highest temperature is considered to be the melting point of the resin material. Other measurement conditions for the melting point of the resin material are in accordance with JIS K7121:2012.

[0123] In an example where the resin layer 60 is in contact with the light-emitting surface 36 of the light-emitting element 35 as shown in FIG. 2A etc., an upper and lower limit may be set for the density of the resin material that constitutes the resin layer 60. The density of the resin material that constitutes the resin layer 60 is 0.875 g / cm 3 More than 0.900g / cm 3 More than 0.91g / cm 3 The density of the resin material constituting the resin layer 60 is 0.930 g / cm 3 Less than 0.925g / cm 3 Less than 0.92g / cm 3 The following is also acceptable.

[0124] By setting the density of the resin material constituting the resin layer 60 within the above range, flexibility, transparency, and processability can be improved. By setting a lower limit for the density of the resin material constituting the resin layer 60, sufficient heat resistance can be imparted to the resin layer 60. By setting an upper limit for the density of the resin material constituting the resin layer 60, the resin layer 60 can be adhered to the light emitting substrate 30 with sufficient adhesion strength.

[0125] The density of the resin material constituting the resin layer 60 is a value measured by the pycnometer method in accordance with JIS K7112:2023. The immersion liquid is freshly distilled water containing 0.1% or less of a wetting agent. The temperature of the immersion liquid is 23°C ± 0.5°C. Other measurement conditions for the density of the resin material are in accordance with JIS K7112:2023.

[0126] The resin layer 60 includes an olefin-based resin. The resin layer 60 may include an olefin-based resin as a base resin. The base resin is the resin component with the largest content ratio in the resin layer 60. The olefin-based resin may be the component with the largest content ratio in the resin layer 60.

[0127] Olefin-based resins have excellent long-term stability. The resin layer 60 containing an olefin-based resin as a base resin can suppress a decrease in strength and gas generation, thereby suppressing deterioration of the light-emitting element 35 and the wiring layer 42. The resin layer 60 containing an olefin-based resin as a base resin can achieve the above-mentioned preferred numerical ranges for the total light transmittance, transmission haze, refractive index, melt mass flow rate, melting point, and density.

[0128] Examples of olefin-based resins include polyethylene, polypropylene, cyclic olefin copolymers, and ethylene copolymers. Examples of ethylene copolymers include ethylene-tetrafluoroethylene copolymers. The resin layer 60 may contain one or more of polyethylene, polypropylene, cyclic olefin copolymers, and ethylene copolymers. Such a resin layer 60 can stably achieve the above-mentioned preferred ranges for the total light transmittance, transmission haze, refractive index, melt mass flow rate, melting point, and density.

[0129] The resin layer 60 may contain polyethylene as an olefin-based resin. The resin layer 60 may contain ordinary polyethylene obtained by polymerizing ethylene. The resin layer 60 may contain a copolymer of ethylene and an α-olefin.

[0130] The α-olefin may be an α-olefin having 3 to 12 carbon atoms. Examples of α-olefins include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-methyl-pentene-1, 4-methyl-hexene-1, and 4,4-dimethylpentene-1. The resin layer 60 may contain one type of α-olefin alone. The resin layer 60 may contain two or more types of α-olefins.

[0131] The resin layer 60 may contain an unbranched α-olefin. The resin layer 60 may contain an unbranched α-olefin having a carbon number of 3 or more and 8 or less. Examples of such α-olefins include 1-propene, 1-butene, 1-pentene, 1-hexene, 1-heptene, and 1-octene. When the carbon number of the α-olefin is 3 or more and 8 or less, the resin layer 60 can be imparted with excellent flexibility and excellent strength. The adhesion of such a resin layer 60 to the light emitting substrate 30 is improved.

[0132] Specific examples of ethylene-α-olefin copolymers include ethylene-propylene copolymer, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, ethylene-1-octene copolymer, and ethylene-4-methyl-pentene-1 copolymer.

[0133] Examples of polyethylene include high-density polyethylene (HDPE), low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), metallocene linear low-density polyethylene (M-LLDPE), and very low-density polyethylene (VLDPE). The resin layer 60 may contain one type of polyethylene alone. The resin layer 60 may also contain two or more types of polyethylene.

[0134] Low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), metallocene-based linear low-density polyethylene (M-LLDPE), and very low-density polyethylene (VLDPE) can improve the flexibility, transparency, and processability of the resin layer 60. Metallocene-based linear low-density polyethylene (M-LLDPE) is synthesized using a single-site metallocene catalyst. This type of polyethylene has few side chain branches and a uniform comonomer distribution. Its narrow molecular weight distribution allows for low density, imparting excellent flexibility to the resin layer 60. The excellent flexibility of the resin layer 60 improves adhesion between the resin layer 60 and the light-emitting substrate 30 or the transparent plate 28. Low-density polyethylene has a narrow crystallinity distribution and uniform crystal size. Large crystal sizes are absent, and the low density results in low crystallinity. Therefore, the transparency of the resin layer 60 is improved.

[0135] The content of the olefin-based resin may be 75 parts by mass or more, 90 parts by mass or more, or 95 parts by mass or more, relative to 100 parts by mass of all resin components contained in the resin layer 60. By adjusting the content of the olefin-based resin in this manner, it is possible to improve the transparency and flexibility of the resin layer 60. The proportion of each resin component contained in the resin layer 60 is determined from the peak ratio detected by infrared spectroscopy (IR).

[0136] The resin layer 60 may contain a crosslinking agent. A resin layer 60 containing a crosslinking agent will contain a crosslinked structure. A resin layer containing a crosslinked structure is also called a resin layer containing a cured resin. The crosslinking agent used in the resin layer 60 is determined to have a crosslinked structure if the gel fraction measured in accordance with JIS K6796:2003 is greater than 0%, and is not particularly limited. The resin layer 60 may contain a single type of crosslinking agent. The resin layer 60 may contain two or more types of crosslinking agents.

[0137] The molecular weight of the organic peroxide may be 200 or more, or 220 or more. The molecular weight of the organic peroxide may be 350 or less, or 300 or less. If the molecular weight of the organic peroxide is within this range, it is possible to generate a sufficient amount of radicals to ensure crosslinking points. In addition, it is possible to suppress outgassing, which is a decomposition product of the organic peroxide.

[0138] The one-hour half-life temperature of the organic peroxide is preferably, for example, 110°C or higher and 145°C or lower. Here, the half-life of the organic peroxide refers to the time it takes for the organic peroxide to decompose due to heat and for the amount of active oxygen to be reduced to half of the amount before decomposition. If the one-hour half-life temperature of the organic peroxide is equal to or higher than a predetermined value, crosslinking can be suppressed during film formation. Furthermore, if the one-hour half-life temperature of the organic peroxide is equal to or lower than a predetermined value, radicals can be reliably generated during the module integration process.

[0139] The amount of active oxygen in the organic peroxide may be 5.0% or more and 10.0% or less. When the amount of active oxygen in the organic peroxide is equal to or more than a predetermined value, a sufficient amount of radicals necessary for crosslinking between the polyolefin resin and the crosslinking aid can be generated.

[0140] Examples of organic peroxides include peroxycarbonates, peroxyketals, and dialkyl peroxides. Examples of peroxycarbonates include t-amyl-peroxy-2-ethylhexyl carbonate and t-butylperoxy-2-ethylhexyl carbonate. Examples of peroxyketals include n-butyl 4,4-di(t-butylperoxy)valerate, ethyl 3,3-di(t-butylperoxy)butyrate, and 2,2-di(t-butylperoxy)butane. Examples of dialkyl peroxides include di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, 2,5-dimethyl-2,5-di(t-butylperoxy)hexane, and 2,5-dimethyl-2,5-di(t-peroxy)hexyne-3.

[0141] The content of the cross-linking agent in the resin layer 60 may be 0.35% by mass or more, 0.40% by mass or more, or 0.44% by mass or more. The content of the cross-linking agent in the resin layer 60 may be 0.50% by mass or less, 0.48% by mass or less, or 0.47% by mass or less. If the content of the cross-linking agent is low, the degree of cross-linking after cross-linking will be low. This may reduce the gel fraction and heat resistance. If the content of the cross-linking agent is high, outgassing may occur. Outgassing causes bubbles.

[0142] The resin layer 60 may contain a cross-linking aid.

[0143] The cross-linking aid is not particularly limited. The cross-linking aid may be a polyfunctional monomer having a polymerizable functional group. When the resin layer 60 contains such a cross-linking aid, an appropriate cross-linking reaction in the resin layer 60 can be promoted. As a result, it is possible to prevent unreacted cross-linking agent from remaining. It is also possible to prevent outgassing caused by unreacted cross-linking agent. By promoting the cross-linking reaction with the cross-linking aid, it is possible to improve the adhesion between the resin layer 60 and the portions adjacent to the resin layer 60. The cross-linking aid reduces the crystallinity of the polyolefin resin, thereby maintaining the transparency of the resin layer 60.

[0144] From the viewpoint of improving reactivity, the crosslinking aid may be a nurate ring-containing compound, which contains two or more polymerizable functional groups in one molecule.

[0145] The number of polymerizable functional groups per molecule may be two or more. The number of polymerizable functional groups per molecule may be six or less, or three or less. If the number of polymerizable functional groups is small, the crosslinking density may be reduced. If the number of polymerizable functional groups is large, the resin layer 60 may become brittle after crosslinking treatment, which may adversely affect the physical properties of the resin layer 60.

[0146] The polymerizable functional group may react with the olefin resin base resin to form a crosslinked structure. Examples of the polymerizable functional group include groups having a carbon-carbon double bond, such as a vinyl group, a (meth)acryloyl group, a (meth)acryloyloxy group, and an allyl group, and an epoxy group.

[0147] Examples of crosslinking aids include polyallyl compounds, poly(meth)acryloxy compounds, and epoxy compounds. Examples of polyallyl compounds include triallyl isocyanurate (TAIC), triallyl cyanurate, diallyl phthalate, diallyl fumarate, and diallyl maleate. Examples of poly(meth)acryloxy compounds include trimethylolpropane trimethacrylate (TMPT), trimethylolpropane triacrylate (TMPTA), ethylene glycol diacrylate, ethylene glycol dimethacrylate, 1,4-butanediol diacrylate, 1,6-hexanediol diacrylate, and 1,9-nonanediol diacrylate. Examples of epoxy compounds include glycidyl methacrylate or 4-hydroxybutyl acrylate glycidyl ether, which contain a double bond and an epoxy group. The epoxy compound may be 1,6-hexanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, or trimethylolpropane polyglycidyl ether, each of which contains two or more epoxy groups. The resin layer 60 may contain a single cross-linking aid. The resin layer 60 may contain two or more cross-linking aids.

[0148] The cross-linking aid may be triallyl isocyanurate (TAIC). Triallyl isocyanurate (TAIC) can improve the adhesion of the resin layer 60 to the light emitting substrate 30 and the transparent plate 28. Triallyl isocyanurate (TAIC) is highly compatible with linear low-density polyethylene. Therefore, cross-linking reduces crystallinity, thereby improving transparency. Triallyl isocyanurate (TAIC) can also impart flexibility to the resin layer 60 at low temperatures.

[0149] The content of the cross-linking aid contained in the resin layer 60 may be 0.40% by mass or more, 0.45% by mass or more, or 0.50% by mass or more. The content of the cross-linking aid contained in the resin layer 60 may be 0.80% by mass or less, 0.70% by mass or less, or 0.60% by mass or less. By setting the content of the cross-linking aid within this numerical range, it is possible to promote an appropriate cross-linking reaction. By setting the content of the cross-linking aid within this numerical range, it is possible to suppress bleeding out of the cross-linking aid.

[0150] The resin layer 60 may contain a silane component. When the resin layer 60 contains a silane component, it is possible to improve the adhesion between the resin layer 60 and other parts adjacent to the resin layer 60. Examples of the silane component include a silane coupling agent and a silane-modified polyolefin resin.

[0151] The silane coupling agent is not particularly limited. Examples of silane coupling agents include methacryloxy-based silane coupling agents, acryloxy-based silane coupling agents, epoxy-based silane coupling agents, and mercapto-based silane coupling agents. The methacryloxy-based silane coupling agents and acryloxy-based silane coupling agents are not particularly limited. Examples of methacryloxy-based silane coupling agents and acryloxy-based silane coupling agents include 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropylmethyldimethoxysilane, 3-acryloxypropylmethyldiethoxysilane, 3-methacryloxypropylmethyldimethoxysilane, and 3-methacryloxypropylmethyldiethoxysilane. The resin layer 60 may contain a single type of silane coupling agent. The resin layer 60 may contain two or more types of silane coupling agents.

[0152] The content of the silane coupling agent in the resin layer 60 may be 0.05% by mass or more, 0.10% by mass or more, or 0.15% by mass or more. The content of the silane coupling agent in the resin layer 60 may be 0.30% by mass or less, 0.27% by mass or less, or 0.25% by mass or less. By setting a lower limit for the content of the silane coupling agent, the adhesion-improving function of the silane coupling agent can be fully utilized. By setting an upper limit for the content of the silane coupling agent, film-forming properties can be ensured. By setting an upper limit for the content of the silane coupling agent, bleeding out of the silane coupling agent can be suppressed.

[0153] The silane-modified polyolefin resin is a copolymer of an α-olefin and an ethylenically unsaturated silane compound. This copolymer may be a random copolymer, an alternating copolymer, a block copolymer, or a graft copolymer. The graft copolymer can improve the adhesion between the resin layer 60 and the light-emitting substrate 30 or the transparent plate 28. The graft copolymer may be a graft copolymer in which a polyolefin is used as the main chain and an ethylenically unsaturated silane compound is polymerized as a side chain. In such a graft copolymer, the degree of freedom of the silanol groups that contribute to adhesion is increased. Therefore, the adhesion between the resin layer 60 and the light-emitting substrate 30 or the transparent plate 28 can be improved.

[0154] Examples of α-olefins constituting the silane-modified polyolefin resin include ethylene, propylene, 1-butene, isobutylene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 1-heptene, 1-octene, 1-nonene, and 1-decene. The resin layer 60 may contain a single α-olefin. The resin layer 60 may contain two or more α-olefins. The α-olefin may be polyethylene. That is, the silane-modified polyolefin resin may be a silane-modified polyethylene resin. When the olefin-based resin serving as the base resin is polyethylene, the compatibility between the polyethylene and the silane-modified polyethylene resin is good.

[0155] The silane-modified polyethylene resin may be a resin in which an ethylenically unsaturated silane compound is graft-polymerized as a side chain onto a linear low-density polyethylene (LLDPE) main chain.

[0156] Examples of ethylenically unsaturated silane compounds include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, vinyltributoxysilane, vinyltripentyloxysilane, vinyltriphenoxysilane, vinyltribenzyloxysilane, vinyltrimethylenedioxysilane, vinyltriethylenedioxysilane, vinylpropionyloxysilane, vinyltriacetoxysilane, and vinyltricarboxysilane. The resin layer 60 may contain a single type of ethylenically unsaturated silane compound. The resin layer 60 may also contain two or more types of ethylenically unsaturated silane compounds.

[0157] The silane-modified polyolefin resin may be produced, for example, by the production method described in JP2003-46105A.

[0158] The resin layer 60 may contain a single type of silane-modified polyolefin resin, or may contain two or more types of silane-modified polyolefin resins.

[0159] The content of the silane-modified polyolefin resin in the resin layer 60 may be 1% by mass or more, 3% by mass or more, or 5% by mass or more. The content of the silane-modified polyolefin resin in the resin layer 60 may be 20% by mass or less, 18% by mass or less, or 15% by mass or less. By setting a lower limit for the content of the silane-modified polyolefin resin, the adhesion-improving function of the silane-modified polyolefin resin can be fully utilized. By setting an upper limit for the content of the silane-modified polyolefin resin, sufficient tensile elongation and sufficient heat-weldability can be imparted to the resin layer 60.

[0160] The resin layer 60 may contain additives other than the above-mentioned olefin-based resin, crosslinking agent, crosslinking aid, and silane coupling agent. The resin layer 60 may contain one or more of a light stabilizer, an ultraviolet absorber, an antioxidant, a heat stabilizer, a nucleating agent, a dispersant, a leveling agent, a plasticizer, an antifoaming agent, a flame retardant, a filler, etc. The content of the additives contained in the resin layer 60 may be 5% by mass or less.

[0161] Examples of light stabilizers include hindered amine light stabilizers (HALS), such as NH type (hydrogen bonded to a nitrogen atom), NR type (an alkyl group (R) bonded to a nitrogen atom), and N-OR type (an alkoxy group (OR) bonded to a nitrogen atom).

[0162] Weather-resistant agents such as light stabilizers, UV absorbers, and antioxidants may be dispersed in a resin to form a weather-resistant masterbatch, which may be added to the composition for forming the resin layer 60. The weather-resistant masterbatch may be prepared as needed. The weather-resistant masterbatch may be a commercially available product. The resin used in the weather-resistant masterbatch may be the above-mentioned olefin-based resin or another resin.

[0163] The resin layer 60 may include biomass material. 14 The resin layer 60 is a biomass-derived raw material having a biomass content calculated from the measured value of C. 14 The resin layer 60 may contain a biomass-derived polyolefin having a biomass degree calculated from the measured value of C. More specifically, the resin layer 60 may contain a biomass-derived polyethylene having a biomass degree. By using a biomass material, the environmental load can be reduced.

[0164] Biomass-derived ethylene can be produced using biomass-derived ethanol as a raw material. Biomass-derived ethylene may be produced using biomass-derived fermented ethanol obtained from a plant raw material as a raw material. The plant raw material is not particularly limited. The plant raw material may be a conventionally known plant. Examples of plant raw materials include corn, sugarcane, beet, and manioc.

[0165] Fermented ethanol derived from biomass refers to ethanol produced by contacting a culture solution containing a carbon source obtained from plant raw materials with an ethanol-producing microorganism or a product derived from the disrupted microorganism, followed by purification. Conventional methods such as distillation, membrane separation, and extraction can be used to purify ethanol from the culture solution. Examples of methods for purifying ethanol from the culture solution include adding benzene, cyclohexane, etc., and removing water by azeotropy or membrane separation.

[0166] In recent years, with growing calls for the creation of a recycling-oriented society, there is a desire to move away from fossil fuels in the materials field, just as there is in energy. In this trend, the use of biomass has been attracting attention. Biomass is an organic compound produced by photosynthesis from carbon dioxide and water. Biomass is a so-called carbon-neutral renewable energy source that can be converted back into carbon dioxide and water. Recently, the practical application of biomass plastics made from these biomass materials has been progressing rapidly. Attempts are being made to produce various resins from biomass raw materials.

[0167] The biomass degree of the resin layer 60 may be 5% by mass or more, 25% by mass or more, or 50% by mass or more. There is no upper limit set for the biomass degree of the resin layer 60. The biomass degree of the resin layer 60 may be 100% by mass or less, or may be less than 100% by mass.

[0168] Whether or not a sealing material contains biomass polyethylene and its content can be measured in accordance with ISO 16620-2 Method C (AMS method for Carbon-14 (radiocarbon) analysis).

[0169] <<<Application example>>> There is no particular limitation on the use of the light emitting device 20. The light emitting device 20 may be used as a display device 10. The light emitting device 20 may be used as a lighting device.

[0170] In the light-emitting device 20 constituting the dot-matrix display device 10, each light-emitting element 35 constitutes one pixel. Light from each light-emitting element 35 passes through the sealing sheet 50 and the transparent plate 28. An image can be displayed by independently controlling the emission and non-emission of the multiple light-emitting elements 35 included in the light-emitting device 20.

[0171] In the examples shown in FIGS. 5 and 6 , the light-emitting device 20 constitutes a part of the surface light source device 15. The surface light source device 15 functions as a backlight and illuminates the display panel 12 from behind. The surface light source device 15 may include the light-emitting device 20 and an optical member 18 overlaid on the light-emitting device 20. The optical member 18 adjusts the direction of travel of light from the light-emitting device 20. The optical member 18 may include one or more of a light diffusion sheet, a lens sheet, a prism sheet, and a brightness improvement sheet. The surface light source device 15 includes a light-emitting surface 15a facing the display panel 12. Light is emitted from the light-emitting surface 15a. The optical member 18 may adjust the illuminance distribution and luminance angle distribution on the light-emitting surface 15a of the surface light source device 15. The display panel 12 is illuminated from a second side in the first direction D1 by planar light from the light-emitting surface 15a. The display panel 12 forms an image by controlling the transmission state for each pixel.

[0172] In addition, when the light emitting device 20 is increased in size, the light emitting substrate 30 may be divided into component light emitting substrates 30E along at least one of the second direction D2 and the third direction D3. In the example shown in Fig. 7, a plurality of component light emitting substrates 30E are arranged in the first direction D1, and a plurality of component light emitting substrates 30E are arranged in the second direction D2. One light emitting substrate 30 is composed of the plurality of component light emitting substrates 30E.

[0173] The light emitting device 20 may include components other than the light emitting substrate 30, the encapsulating sheet 50, and the transparent plate 28. For example, as shown in FIG. 2C , the light emitting device 20 may include a surface layer 29. The surface layer 29 may be a low-reflection layer having a reflection suppressing function, an antiglare layer having an antiglare function, an antistatic layer having an antistatic function, or an antifouling layer having an antifouling function. The light emitting device 20 may include a wavelength conversion layer that converts the wavelength of light emitted from the light emitting element 35. The wavelength conversion layer may contain a wavelength conversion agent such as quantum dots. At least one of the encapsulating sheet 50 and the transparent plate 28 may contain a wavelength conversion agent such as quantum dots.

[0174] The encapsulating sheet 50 may include a layer other than the resin layer 60. As shown in Fig. 2D , the encapsulating sheet 50 may include a light-shielding layer 66. In the example shown in Fig. 2D , the encapsulating sheet 50 includes the light-shielding layer 66 and the resin layer 60 from the light-incident side surface 51 to the light-emitting side surface 52 in the first direction D1.

[0175] The light-shielding layer 66 has light-shielding properties. The total light transmittance of the light-shielding layer 66 having light-shielding properties may be 40% or less, 30% or less, 10% or less, or 5% or less. There is no particular lower limit set for the total light transmittance of the light-shielding layer 66. The total light transmittance of the light-shielding layer 66 may be 0% or more, or may be greater than 0%.

[0176] As shown in FIG. 2D , the light-shielding layer 66 may be disposed between adjacent light-emitting elements 35. The light-shielding layer 66 may be located in a region of the surface of the light-emitting substrate 30 facing the first side in the first direction D1, other than the light-emitting elements 35. The light-shielding layer 66 may cover the wiring layer 42 exposed to the first side of the light-emitting substrate 30 in the first direction D1. The light-shielding layer 66 may cover the wiring 42X exposed to the first side of the light-emitting substrate 30 in the first direction D1. The light-shielding layer 66 can suppress reflection of external light incident on the light-emitting substrate 30, for example, reflection on the wiring layer 42 (wiring 42X). This can improve the contrast of a displayed image in an example in which the light-emitting device 20 constitutes a dot-matrix display device 10.

[0177] The light-shielding layer 66 may be a layer containing a pigment. The light-shielding layer 66 may include a binder resin portion and a pigment dispersed in the binder resin portion. The pigment may be a black pigment such as carbon black or titanium black. The light-shielding layer 66 may include multiple types of color pigments. The light-shielding layer 66 may include one or more of a blue pigment, a green pigment, a red pigment, and a yellow pigment as the color pigment.

[0178] The light-shielding layer 66 may be patterned on the resin layer 60. For example, the light-shielding layer 66 may be patterned by forming the light-shielding layer 66 on the resin layer 60 by coating.

[0179] The encapsulating sheet 50 shown in FIG. 8A may be used. In the encapsulating sheet 50 shown in FIG. 8A, the light-shielding layer 66 is not patterned. In this example, the complex shear viscosity (Pa s) of the light-shielding layer 66 may be adjusted. The complex shear viscosity (Pa s) of the light-shielding layer 66 may be smaller than the complex shear viscosity (Pa s) of the resin layer 60. The complex shear viscosity ratio of the light-shielding layer 66 may be 80% or less, 50% or less, or 10% or less. The complex shear viscosity ratio of the light-shielding layer 66 is the ratio (%) of the complex shear viscosity of the reflective layer 67 to the complex shear viscosity of the resin layer 60.

[0180] By adjusting the complex shear viscosity and the complex shear viscosity ratio of the light-shielding layer 66 as described above, when the encapsulating sheet 50 is heated and pressed onto the light-emitting substrate 30, the light-shielding layer 66 migrates in the first direction D1 from above the light-emitting element 35. The material constituting the light-shielding layer 66 can migrate from the region facing the light-emitting element 35 in the first direction D1 to a direction perpendicular to the first direction D1. The material constituting the light-shielding layer 66 can migrate from the region facing the light-emitting element 35 to a region between the light-emitting elements 35. This results in the light-emitting device 20 shown in FIG. 2D being obtained.

[0181] 8A before the heating and pressurizing treatment may be equal to or less than the product of the thickness TL of the light-emitting element 35 and the proportion of the area other than the light-emitting element 35 on the surface of the light-emitting substrate 30 facing the sealing sheet 50 when observed from the first direction D1. The proportion of the area other than the light-emitting element 35 on the surface of the light-emitting substrate 30 facing the sealing sheet 50 when observed from the first direction D1 is a unitless numerical value greater than 0 and less than 1. This thickness adjustment can prevent the light-shielding layer 66 from remaining on the light-emitting element 35.

[0182] 2D, the light emitting element 35 is not covered in the first direction D1 by the light blocking layer 66. Therefore, the utilization efficiency of the light emitted from the light emitting element 35 can be maintained high.

[0183] The measurement conditions for complex shear viscosity (Pa·s) are as follows: Other conditions for measuring complex shear viscosity are values ​​measured in accordance with JIS K7244-10:2005. (Measurement conditions) Sealing temperature: 160℃ Parallel plate diameter: 1mm Parallel plate distance: Thickness of the part to be measured (for example, resin layer, light-shielding layer, reflective layer described later) Angular frequency: 1 / sec

[0184] 2E, the encapsulating sheet 50 may include a reflective layer 67. In the example shown in Fig. 2E, the encapsulating sheet 50 includes the reflective layer 67 and the resin layer 60 from the light-incident side surface 51 to the light-emitting side surface 52 in the first direction D1.

[0185] The reflective layer 67 has reflectivity. The total light reflectance of the reflective layer 67 having reflectivity may be 30% or more, 50% or more, or 70% or more. There is no particular upper limit set for the total light reflectance of the reflective layer 67. The total light reflectance of the reflective layer 67 may be 100% or less, or may be less than 100%.

[0186] Total luminous reflectance is the sum of diffuse reflectance and specular reflectance. A D65 light source is used to measure total luminous reflectance. The wavelength range of light used to measure total luminous reflectance (%) is 380 nm to 780 nm. Before measuring the total luminous reflectance of the sample, the D65 light source is turned on for 15 minutes to stabilize the output of the D65 light source. The angle of incidence on the sample when measuring total luminous reflectance is 7°. The test environment for measuring total luminous reflectance is a temperature of 23°C ± 2°C and a relative humidity of 50% ± 5%. The sample is left in the test environment for 16 hours before starting the test. Other measurement conditions for measuring total luminous transmittance follow JIS K7375:2008.

[0187] 2E, the reflective layer 67 may be disposed at a position between adjacent light-emitting elements 35. The reflective layer 67 may be located in an area of ​​the surface of the light-emitting substrate 30 facing the first side in the first direction D1 other than the light-emitting elements 35. The reflective layer 67 may cover the light-emitting surface of the entire light-emitting surface 36 of the light-emitting element 35 that faces in a direction significantly inclined with respect to the first direction D1. The reflective layer 67 may cover the light-emitting surface of the light-emitting surface 36 of the light-emitting element 35 that is along the first direction D1.

[0188] The light-emitting surface 36 may include a surface facing a direction significantly inclined with respect to the first direction D1. Light emitted from the light-emitting surface 36 facing a direction significantly inclined with respect to the first direction D1 may become stray light. In an example in which the light-emitting device 20 constitutes a dot-matrix display device 10, light emitted from the light-emitting surface 36 facing a direction significantly inclined with respect to the first direction D1 does not contribute to image formation and may actually reduce the visibility of the image. The reflective layer 67 can return light emitted from the light-emitting surface 36 facing a direction significantly inclined with respect to the first direction D1, thereby enabling effective use of the light. Therefore, the utilization efficiency of the light emitted from the light-emitting element 35 can be maintained at a high level. Furthermore, the light-emitting device 20 constituting the dot-matrix display device 10 can display images with excellent visibility.

[0189] The reflective layer 67 may be a layer containing a diffusing component. The reflective layer 67 may include a binder resin portion and a diffusing component dispersed in the binder resin portion. Examples of the diffusing component include particles having a refractive index different from that of the binder resin portion, white particles, particles made of a highly reflective material (e.g., metal particles), and air bubbles.

[0190] The reflective layer 67 may be patterned on the resin layer 60. For example, the reflective layer 67 may be patterned by forming the reflective layer 67 on the resin layer 60 by coating.

[0191] The encapsulating sheet 50 shown in FIG. 8B may be used. In the encapsulating sheet 50 shown in FIG. 8B, the reflective layer 67 is not patterned. In this example, the complex shear viscosity (Pa s) of the reflective layer 67 may be adjusted. Specifically, the complex shear viscosity of the reflective layer 67 may be smaller than the complex shear viscosity of the resin layer 60. The complex shear viscosity ratio of the reflective layer 67 may be 80% or less, 50% or less, or 10% or less. The complex shear viscosity ratio of the reflective layer 67 is the ratio (%) of the complex shear viscosity of the reflective layer 67 to the complex shear viscosity of the resin layer 60.

[0192] By adjusting the complex shear viscosity (Pa s) and the complex shear viscosity ratio (%) of the reflective layer 67 as described above, when the encapsulating sheet 50 is heated and pressed onto the light emitting substrate 30, the reflective layer 67 moves from above the light emitting element 35. The material constituting the reflective layer 67 can move from the region facing the light emitting element 35 in the first direction D1 to a direction perpendicular to the first direction D1. The material constituting the reflective layer 67 can move from the region facing the light emitting element 35 to a region between the light emitting elements 35. This results in the light emitting device 20 shown in FIG. 2E being obtained.

[0193] 8B before the heating and pressurizing treatment may be equal to or less than the product of the thickness TL of the light emitting element 35 and the proportion of the area other than the light emitting element 35 on the surface of the light emitting substrate 30 facing the sealing sheet 50 when observed from the first direction D1. The proportion of the area other than the light emitting element 35 on the surface of the light emitting substrate 30 facing the sealing sheet 50 when observed from the first direction D1 is a unitless numerical value greater than 0 and less than 1. This thickness adjustment can prevent the reflective layer 67 from remaining on the light emitting element 35.

[0194] As shown in FIG. 2F , the encapsulating sheet 50 may include a light-shielding layer 66 and a reflective layer 67. In the example shown in FIG. 2F , the encapsulating sheet 50 includes, from the light-incident side surface 51 toward the light-exiting side surface 52 in the first direction D1, the reflective layer 67, the light-shielding layer 66, and the resin layer 60. The light-shielding layer 66 may be configured similarly to the light-shielding layer 66 described with reference to FIGS. 2D and 8A . The reflective layer 67 may be configured similarly to the reflective layer 67 described with reference to FIGS. 2E and 8B .

[0195] The encapsulating sheet 50 shown in FIG. 2F can be obtained by applying heat and pressure to the encapsulating sheet 50 shown in FIG. 8C on the light emitting substrate 30. In the encapsulating sheet 50 shown in FIG. 8C, the complex shear viscosity of the light-shielding layer 66 may be adjusted similarly to the complex shear viscosity of the light-shielding layer 66 shown in FIG. 8A described above. In the encapsulating sheet 50 shown in FIG. 8C, the complex shear viscosity ratio of the light-shielding layer 66 may be adjusted similarly to the complex shear viscosity ratio of the light-shielding layer 66 shown in FIG. 8A described above. In the encapsulating sheet 50 shown in FIG. 8C, the complex shear viscosity of the reflective layer 67 may be adjusted similarly to the complex shear viscosity of the reflective layer 67 shown in FIG. 8B described above. In the encapsulating sheet 50 shown in FIG. 8C, the complex shear viscosity ratio of the reflective layer 67 may be adjusted similarly to the complex shear viscosity ratio of the reflective layer 67 shown in FIG. 8B described above. By adjusting the complex shear viscosity and the complex shear viscosity ratio of the light-shielding layer 66 and the reflective layer 67 to fall within the above-mentioned ranges, when the encapsulating sheet 50 is heated and pressed onto the light-emitting substrate 30, the light-shielding layer 66 and the reflective layer 67 can be patterned as described above.

[0196] 2G, the encapsulating sheet 50 may include a patterned light-shielding layer 68. In the example shown in Fig. 2G, the encapsulating sheet 50 includes a resin layer 60 and a patterned light-shielding layer 68 from the light-incident side surface 51 toward the light-emitting side surface 52 in the first direction D1. The patterned light-shielding layer 68 includes an opening 68a at a position above the light-emitting element 35. The opening 68a is located in a region facing the light-emitting element 35 in the first direction D1.

[0197] The patterned light-shielding layer 68 has light-shielding properties in areas other than the openings 68a. The total light transmittance of the patterned light-shielding layer 68 in areas other than the openings 68a may be 40% or less, 30% or less, 10% or less, or 5% or less. There is no particular lower limit set for the total light transmittance of the patterned light-shielding layer 68 in areas other than the openings 68a. The total light transmittance of the light-shielding layer 68 in areas other than the openings 68a may be 0% or more, or may be greater than 0%. The patterned light-shielding layer 68 can improve the contrast of a displayed image in an example in which the light-emitting device 20 constitutes a dot-matrix display device 10.

[0198] The patterned light-shielding layer 68 may be a layer containing a pigment. The patterned light-shielding layer 68 may include a binder resin portion and a pigment dispersed in the binder resin portion. The pigment may be a black pigment such as carbon black or titanium black. The patterned light-shielding layer 68 may include multiple types of colored pigments. The patterned light-shielding layer 68 may include one or more of a blue pigment, a green pigment, a red pigment, and a yellow pigment as the colored pigment.

[0199] The patterned light-shielding layer 68 may be patterned on the resin layer 60. For example, the patterned light-shielding layer 68 may be patterned by forming the patterned light-shielding layer 68 on the resin layer 60 by coating.

[0200] <<<Improvement of encapsulating sheets>>> Conventional encapsulating sheets have not been able to adequately protect the light-emitting element while maintaining the characteristics of the light-emitting device. In the present embodiment, the encapsulating sheet is improved to adequately protect the light-emitting element while maintaining the characteristics of the light-emitting device. Hereinafter, first, second, and third aspects of the improvement of the encapsulating sheet 50 will be described in order. The first, second, and third aspects are applicable to the encapsulating sheet 50 of the light-emitting device 20 described above.

[0201] <<First Aspect>> In the first embodiment, the optical characteristics of the light-emitting device 20 are improved. The encapsulating sheet 50 according to the first embodiment can adequately protect the light-emitting elements 35 while maintaining the light-emitting characteristics of the light-emitting elements 35. For example, in a light-emitting device 20 constituting a dot-matrix display device 10, it is preferable that light from each light-emitting element 35 is emitted from the light-emitting device 20 without being significantly diffused. If the light from each light-emitting element 35 is significantly diffused, it becomes difficult to distinguish between light from different light-emitting elements 35. In this case, it becomes difficult for the viewer to distinguish each pixel from other pixels. The contours of the displayed image become less sharp. Therefore, the quality of the displayed image is reduced.

[0202] To address this problem, the light emitting device 20 according to the first aspect of the present embodiment has the following characteristics related to brightness. The brightness on the light-emitting side surface 52 of the encapsulating sheet 50 above one light emitting element 35 is defined as a first brightness (cd / m 2 The luminance on the light emitting surface 36 of the one light emitting element 35 is defined as a second luminance (cd / m 2 The luminance ratio (%), which is the ratio of the first luminance to the second luminance, is 90% or more. The luminance ratio may be 93% or more, 95% or more, or 97% or more.

[0203] By setting a lower limit to the luminance ratio, it is possible to suppress light diffusion in the encapsulating sheet 50 and also reduce loss in the encapsulating sheet 50. This makes it possible to suppress mixing of light from different light-emitting elements 35 in the light-emitting device 20 constituting the dot-matrix display device 10. Therefore, it is possible to improve the display quality of the light-emitting device 20 constituting the dot-matrix display device 10. An observer can clearly view an image displayed by the light-emitting device 20.

[0204] There is no particular upper limit set for the brightness percentage, and the brightness percentage may be 100% or less.

[0205] The first luminance is measured in a state where a layer on the first side of the encapsulating sheet 50 in the first direction D1, such as the transparent plate 28, is removed. The first luminance is the luminance on the light-emitting side surface 52 of the encapsulating sheet 50. The first luminance is measured from the first direction D1, which is the direction in which the light-emitting substrate 30 and the encapsulating sheet 50 are stacked. The position at which the first luminance is measured is a position on the light-emitting side surface 52 facing one of the light-emitting elements 35 in the first direction D1.

[0206] The second luminance is measured with layers, such as the transparent plate 28 and the sealing sheet 50, on the first side of the light-emitting element 35 in the first direction D1 removed. The second luminance is the luminance on the light-emitting surface 36 of the light-emitting element 35. The second luminance is measured from the first direction D1, which is the direction in which the light-emitting substrate 30 and the sealing sheet 50 are stacked. The position at which the second luminance is measured is a position facing the position on the light-emitting side surface 52 at which the first luminance was measured, in the first direction D1.

[0207] When the light-emitting substrate 30 includes only light-emitting elements 35 of a single color, the first luminance and the second luminance are measured for each of three arbitrarily selected light-emitting elements 35. Three calculated values ​​of the luminance percentage (%) are obtained from the three measured values ​​of the first luminance and the three measured values ​​of the second luminance. The luminance percentage (%) is determined by the arithmetic mean of the three luminance percentage (%) values.

[0208] When the light emitting substrate 30 includes light emitting elements 35 of multiple colors, the luminance ratio (%) for the light emitting elements 35 of the same color is determined as the arithmetic mean value of the calculated values ​​of three luminance ratios (%) for the light emitting elements 35 of that color. When the light emitting substrate 30 includes light emitting elements 35 of multiple colors, all of the luminance ratios determined based on the light emitting elements 35 of each color satisfy the above-mentioned upper limit.

[0209] The luminance ratio can be adjusted by adjusting the crystallinity of the resin layer 60. The luminance ratio can be increased by decreasing the crystallinity or reducing the size of the crystals. When manufacturing the resin layer 60 by extrusion molding or the like, or when heating and pressurizing the encapsulating sheet 50 toward the light emitting substrate 30, the crystallinity can be decreased and the size of the crystals can be reduced by increasing the cooling rate or lowering the processing temperature.

[0210] The luminance ratio can also be adjusted by adjusting the contact ratio between the light-emitting surface 36 of the light-emitting element 35 and the resin layer 60. By increasing the contact ratio, the luminance ratio can be increased. The contact ratio is the area ratio (%) of the portion of the light-emitting surface 36 that is in contact with the resin layer 60. The contact ratio is preferably 90% or more, and more preferably 95% or more.

[0211] The luminance ratio can be increased by improving the transparency of the encapsulating sheet 50. From the viewpoint of ensuring the transparency of the encapsulating sheet 50, it is effective to adjust the physical property values ​​of the encapsulating sheet 50 and the resin layer 60 as described above.

[0212] For example, an upper limit may be set for the transmission haze of the encapsulating sheet 50 and the transmission haze of the resin layer 60. The transmission haze of the encapsulating sheet 50 and the transmission haze of the resin layer 60 may be set to 15% or less.

[0213] Furthermore, a lower limit may be set for the total light transmittance of the encapsulating sheet 50 and the total light transmittance of the resin layer 60. For example, the total light transmittance of the encapsulating sheet 50 and the total light transmittance of the resin layer 60 may be set to 85% or more.

[0214] Furthermore, an upper and lower limit may be set for the refractive index of the material that constitutes the resin layer 60. For example, the refractive index of the material that constitutes the resin layer 60 may be set to 1.41 or more and 1.58 or less.

[0215] By improving the fluidity of the resin layer 60 in contact with the light emitting substrate 30, it is possible to increase the contact ratio (%), which is the area ratio of the portion of the light emitting surface 36 that is in contact with the resin layer 60. Increasing the contact ratio (%) increases the brightness ratio (%). Therefore, by improving the fluidity of the resin layer 60 in contact with the light emitting substrate 30, it is possible to increase the brightness ratio.

[0216] For example, a lower limit may be set for the melt mass flow rate at 190° C. of the material that constitutes the resin layer 60. For example, the melt mass flow rate at 190° C. of the material that constitutes the resin layer 60 may be 0.50 g / 10 min or more.

[0217] Furthermore, an upper limit may be set for the melting point of the resin material that constitutes the resin layer 60. For example, the melting point of the resin material that constitutes the resin layer 60 may be set to 145° C. or lower.

[0218] Furthermore, an upper limit may be set for the density of the resin material that constitutes the resin layer 60. For example, the density of the resin material that constitutes the resin layer 60 may be set to 0.930 g / cm 3 The following may also be used.

[0219] <Experiment on the first embodiment> Here, an experiment will be described in which the influence of the luminance ratio on the display image of the light emitting device constituting the dot matrix display device was investigated, but the present embodiment is not limited to the following experiment.

[0220] (Configurations and manufacturing methods of Examples and Comparative Examples) Light emitting devices according to Examples A1 to A4 and Comparative Example A1 were fabricated. The size of the light emitting device was 5 cm x 5 cm in plan view. The light emitting device included a light emitting substrate and a sealing sheet from the second side to the first side in the first direction D1. The fabricated light emitting device had a configuration in which the transparent plate was removed from the light emitting device shown in Figures 1 and 2A. The configurations of Examples A1 to A4 and Comparative Example A1 were identical to each other except for the sealing sheet. That is, Examples A1 to A4 and Comparative Example A1 included the same light emitting substrate.

[0221] The light-emitting substrate included a wiring substrate and a plurality of light-emitting elements. The wiring substrate included a base material, a wiring layer, and a substrate light-shielding layer. All of the plurality of light-emitting elements were light-emitting diodes that emitted blue light. When observed from the first direction D1, each light-emitting element had a rectangular shape. Each side of the rectangle extended parallel to one of the first direction D1 and the second direction D2. The length WL1 of the light-emitting element along the first direction D1 was 200 μm. The length WL2 of the light-emitting element along the second direction D2 was 100 μm. The protrusion length TL of the light-emitting element from the wiring substrate in the first direction D1 was 80 μm.

[0222] The plurality of light-emitting elements were arranged in a square array as shown in Figure 3. The plurality of light-emitting elements were arranged in a first direction D1 at an arrangement pitch PL1. The plurality of light-emitting elements were arranged in a second direction D2 at an arrangement pitch PL2. The arrangement pitch PL1 was 0.4 mm. The arrangement pitch PL2 was 0.4 mm.

[0223] The encapsulating sheet was composed only of a resin layer. As shown in FIG. 4, the resin layer included a first portion as a skin layer, a second portion as a core layer, and a third portion as a skin layer. The first portion, second portion, and third portion were located in this order from the light-incident side surface to the light-emitting side surface in the first direction D1. The first portion constituted the light-incident side surface. The third portion constituted the light-emitting side surface.

[0224] The resin layer including the first to third portions was produced by co-extrusion molding. For the co-extrusion molding, an apparatus including a 300 mm wide T-die was used. For the production of the first to third portions, an extruder with a screw diameter of φ30 mm was used. The raw material composition was heated to 210°C and extrusion molded. The thickness ratio of the first portion, the second portion, and the third portion was 1:6:1. The total thickness of the resin layer 60 including the first to third portions was 200 μm.

[0225] The compositions used to prepare the first to third parts are shown in Table 1. Details of the resin components and additives in Table 1 are as follows. Silane-modified resin 1 (silane-modified polyolefin resin): density 0.902 g / cm 3 , melting point 90℃, melt mass flow rate (MFR) at 190℃ 1.0g / 10min Silane-modified resin 2 (silane-modified polyolefin resin): density 0.886 g / cm 3 , melting point 60℃, melt mass flow rate (MFR) at 190℃ 1.3g / 10min M-LLDPE1 (metallocene-based linear low-density polyethylene): Density 0.880 g / cm 3 , melting point 60℃, melt mass flow rate (MFR) at 190℃ 3.5g / 10min M-LLDPE2 (metallocene-based linear low-density polyethylene): Density 0.901 g / cm 3 , melting point 93℃, melt mass flow rate (MFR) at 190℃ 2.0g / 10min LDPE (low density polyethylene): density 0.919g / cm 3 Melting point: 106°C, Melt mass flow rate (MFR) at 190°C: 3.5g / 10min Crosslinking agent MB (crosslinking agent masterbatch): A masterbatch obtained by impregnating 100 parts by mass of metallocene-based linear low-density polyethylene pellets with 0.5 parts by mass of 2,5-dimethyl-2,5-di(t-butylperoxy)hexane as a crosslinking agent (metallocene-based linear low-density polyethylene: melting point 60°C, density 0.880 g / cm 3 , Melt mass flow rate (MFR) at 190°C: 3.1g / 10min) Weatherproofing batch MB (weatherproofing masterbatch): density 0.880 g / cm 3 A masterbatch was obtained by mixing 100 parts by mass of powder obtained by pulverizing the Ziegler linear low-density polyethylene described above with 3.8 parts by mass of a benzophenol-based ultraviolet absorber, 5 parts by mass of a hindered amine-based light stabilizer, and 0.5 parts by mass of a phosphorus-based heat stabilizer, melting and kneading the mixture, and then pelletizing the mixture.

[0226] Next, the encapsulating sheet made of a resin layer and the light emitting substrate were integrated by heating and pressing to obtain light emitting devices 20 according to Examples A1 to A4 and Comparative Example A1. In the obtained light emitting devices, a plurality of light emitting elements were disposed between the wiring substrate and the encapsulating sheet. A vacuum laminator was used to integrate the light emitting substrate and the encapsulating sheet.

[0227] When the light emitting substrate and the sealing sheet were integrated, a glass plate and a resin film were placed on both sides of the light emitting substrate and the sealing sheet to ensure a uniform thickness. That is, a laminate was prepared in the following order: glass plate / resin film / light emitting substrate (wiring substrate / light emitting element) / sealing sheet / resin film / glass plate. The thickness of the glass plate was 3 mm. The resin film was an ETFE (tetrafluoroethylene-ethylene copolymer) film. The thickness of the resin film was 100 μm.

[0228] The light emitting substrate 30 and the encapsulating sheet 50 were integrated in the following manner. First, the laminate to be processed was placed in a vacuum laminator. The pressure inside the vacuum laminator was reduced over 5.0 minutes. The pair of glass plates of the laminate were pressed toward each other. The applied pressure was increased from 0 kPa to 100 kPa over 5 seconds, and then the applied pressure of 100 kPa was maintained for 7.0 minutes. The temperature inside the vacuum laminator was maintained at 150°C from before the laminate was placed until the laminate was removed.

[0229] The laminate removed from the vacuum laminator was cooled under either "Condition 1" or "Condition 2" as shown in Table 1. Details of "Condition 1" and "Condition 2" are as follows. Condition 1: The laminate was removed from the vacuum laminator and placed on a 1 cm thick iron plate, and cooled to 25°C over 6 minutes. Condition 2: The laminate was removed from the vacuum laminator and placed in an oven maintained at 40°C for 15 minutes, after which the laminate was removed from the oven and placed in an atmosphere at 25°C.

[0230] Thereafter, the resin film and the glass plate were removed from the laminate, thereby obtaining the light emitting devices according to Examples A1 to A4 and Comparative Example A1.

[0231] (Evaluation of Examples and Comparative Examples) The luminance ratio was evaluated for Examples A1 to A4 and Comparative Example A1. As described above, the luminance ratio is the ratio (%) of the first luminance on the light-emitting side surface on one light-emitting element to the second luminance on the light-emitting surface of the one light-emitting element. For each example, the first luminance and the second luminance were measured using the method described above. The first luminance was measured for the light-emitting device. The second luminance was measured for the light-emitting device before the encapsulating sheet was overlaid. The first luminance and the second luminance were measured using a 2D spectroradiometer SR-5000 manufactured by Topcon Technohouse Corporation. The luminance ratio values ​​calculated using the first luminance and the second luminance are shown in Table 1.

[0232] The light-emitting devices according to Examples A1 to A4 and Comparative Example A1 were used as dot matrix display devices. Images displayed by the light-emitting devices functioning as dot matrix display devices were observed. The light-emitting devices were placed 30 cm away from the observer's eyes, and the images displayed by the light-emitting devices were observed. The images were observed in a dark room. The evaluation results based on the following criteria are shown in Table 1. "A": The image was clearly observed without mixing of the light that makes up each pixel. "B": The light from adjacent pixels mixed together, making the image contours less sharp.

[0233] [Table 1]

[0234] <<Second aspect>> In the second embodiment, the generation of bubbles between the light emitting substrate 30 and the resin layer 60 in contact with the light emitting substrate 30, and inside the resin layer 60, can be suppressed.

[0235] When a light emitting device is used in a high temperature environment, gas is released from the light emitting element and the wiring layer of the wiring board. The released gas may collect and form observable bubbles in the encapsulating sheet. The generation of bubbles impairs optical properties. The generation of bubbles also causes abnormal appearance. To address this problem, the light emitting device 20 and the encapsulating sheet 50 according to the second aspect of the present embodiment have the following features.

[0236] In the second embodiment, the resin layer 60 is in contact with the light emitting substrate 30, and the resin material constituting the resin layer 60 has a residual crystal amount at 100°C of 8.0 J / g or more. The residual crystal amount at 100°C is an index showing the amount of crystals remaining at 100°C. The residual crystal amount at 100°C is determined using a differential scanning calorimetry (DSC) curve obtained by DSC. The residual crystal amount at 100°C substantially corresponds to the total value of the endothermic heat at 100°C or higher in the DSC curve.

[0237] By setting a lower limit for the amount of remaining crystallinity at 100°C, the resin layer 60 can maintain a certain degree of crystallinity even at 100°C. It is assumed that the temperature in the environment in which the light emitting device 20 including the resin encapsulating sheet 50 is used will rise to about 80°C. Because the resin layer 60 maintains a certain degree of crystallinity at 100°C, the resin layer 60 can maintain sufficient strength while the light emitting device 20 is in use. This can prevent gas generated from the light emitting substrate 30 from flowing through the resin layer 60 and forming observable bubbles.

[0238] As a result, by setting the residual crystallization amount at 100°C of the resin material constituting the resin layer 60 to 8.0 J / g or more, it is possible to suppress the generation of bubbles. This makes it possible to suppress the deterioration of the optical properties of the encapsulating sheet 50 and the light emitting device 20 and the occurrence of abnormal appearance caused by bubbles. Such an effect is useful in the light emitting device 20 constituting the dot matrix display device 10. In addition, such an effect is also useful in the light emitting device 20 constituting the surface light source device 15.

[0239] From the viewpoint of suppressing the generation of bubbles, the amount of residual crystals at 100°C may be 8.0 J / g or more, 20 J / g or more, 24 J / g or more, 26 J / g or more, 50 J / g or more, or 54 J / g or more.

[0240] An upper limit may be set for the amount of crystals remaining at 100°C. By setting an upper limit for the amount of crystals remaining at 100°C, it is possible to prevent bubbles from forming at the crystal interface. The amount of crystals remaining at 100°C may be 80 J / g or less, 70 J / g or less, or 60 J / g or less.

[0241] The 100°C residual crystal amount is the integral of the endotherm in the range of 100°C to 200°C. The endotherm is determined from a differential scanning calorimetry (DSC) curve. The endotherm is the difference between the calorimetry value at each temperature and the baseline. The 100°C residual crystal amount corresponds to the integral of the function that represents the differential scanning calorimetry curve in the range of 100°C to 200°C. For the function that represents the differential scanning calorimetry curve, the vertical axis of the coordinate system represents the endotherm, and 0 on the vertical axis represents the baseline. The horizontal axis of the coordinate system represents the temperature. The 100°C residual crystal amount corresponds to the area of ​​the region between the baseline and the differential scanning calorimetry curve in the range of 100°C to 200°C.

[0242] The differential scanning calorimetry curve obtained by differential scanning calorimetry is specified in JIS K7121:2012. The differential scanning calorimetry curve shows the amount of heat absorbed from the heating start temperature to the heating end temperature. The heating start temperature is 0°C. The area surrounding the sample to be evaluated is maintained at the heating start temperature, and the temperature of the sample is lowered to the heating start temperature, 0°C. The heating rate is 10°C per minute. The heating end temperature is 200°C. In other words, heating is performed from 0°C to 200°C at a rate of 10°C per minute. Other conditions for differential scanning calorimetry and measurement of the differential scanning calorimetry curve follow JIS K7121:2012.

[0243] The amount of crystals remaining at 100°C can be adjusted by adjusting the crystallinity of the resin layer 60. The amount of crystals remaining at 100°C can be increased by increasing the crystallinity at or below 100°C or by increasing the size of the crystals at or below 100°C. When producing the resin layer 60 by extrusion molding or the like or when heating and pressurizing the encapsulating sheet 50 toward the light emitting substrate 30, the crystallinity can be promoted and the size of the crystals can be increased by slowing down the cooling rate or increasing the processing temperature.

[0244] The amount of crystals remaining at 100°C can also be adjusted by adjusting the fluidity of the resin layer 60 that is in contact with the light emitting substrate 30. By decreasing the fluidity at temperatures below 100°C, the amount of crystals remaining at 100°C can be increased.

[0245] From the viewpoint of reducing the fluidity of the resin layer 60 at 100°C or less, it is effective to adjust the physical property values ​​of the encapsulating sheet 50 and the resin layer 60 as described above. For example, a lower limit may be set for the melting point of the resin material constituting the resin layer 60. For example, the melting point of the resin material constituting the resin layer 60 may be 50°C or higher.

[0246] From the viewpoint of reducing the fluidity of the resin layer 60 at temperatures of 100°C or less, the composition for forming the resin layer 60 may contain a crosslinking agent. For example, by heating a composition containing a crosslinking agent, the resin layer 60 may have a crosslinked structure. In other words, the resin layer 60 may contain a cured product of a curable resin composition (also simply referred to as a cured resin). The resin layer 60 having a crosslinked structure can suppress the generation of bubbles due to gas released from the light emitting substrate 30.

[0247] On the other hand, the resin layer 60 may have high fluidity at temperatures above 100°C, which is not reached in the normal usage environment of the light emitting device 20. By having high fluidity at high temperatures, when the resin layer 60 is heated and pressurized onto the light emitting substrate 30, it is possible to effectively prevent the formation of voids between the resin layer 60 and the light emitting substrate 30 from which the light emitting elements 35 protrude. This makes it possible to prevent deterioration of optical properties due to voids. It is also possible to prevent the occurrence of abnormal appearance due to these voids.

[0248] From the viewpoint of ensuring the fluidity of the resin layer 60 at high temperatures, it is effective to adjust the physical property values ​​of the encapsulating sheet 50 and the resin layer 60 as described above. For example, an upper limit of the melting point of the resin material constituting the resin layer 60 may be set. For example, the melting point of the resin material constituting the resin layer 60 may be 145°C or lower. A lower limit may be set for the melt mass flow rate at 190°C of the material constituting the resin layer 60. For example, the melt mass flow rate at 190°C of the material constituting the resin layer 60 may be 0.50 g / 10 min or higher.

[0249] When a light emitting element 35 with low heat resistance is used, it is difficult to heat the encapsulating sheet 50 to a high temperature and press it against the light emitting substrate 30. When combined with a light emitting element 35 with low heat resistance, it is preferable to lower the melting point of the resin layer 60. By using a resin layer 60 with a low melting point, the processing temperature when integrating the encapsulating sheet 50 and the light emitting substrate 30 can be lowered, and damage to the light emitting element 35 can be reliably avoided. When combined with a light emitting element 35 with low heat resistance, the melting point of the resin material constituting the resin layer 60 may be 105°C or lower, 95°C or lower, or 60°C or lower. Examples of light emitting elements 35 with low heat resistance include OLEDs and elements using quantum dots.

[0250] However, if the melting point of the resin material constituting the resin layer 60 is low, the resin layer 60 will be prone to deformation even in the temperature range of the usage environment of the light emitting device 20, and there is even a possibility that the resin layer 60 will melt. For this reason, it is preferable to suppress the fluidity of the resin layer 60 when combined with a light emitting element 35 having low heat resistance. In other words, it is preferable that the resin layer 60 used in combination with a light emitting element 35 having low heat resistance has low fluidity even in the temperature range of the usage environment.

[0251] For a resin layer 60 used with a light emitting element 35 having low heat resistance, it is effective to set an upper limit on the melt mass flow rate at 190°C of the material constituting the resin layer 60 in order to suppress flow during use of the light emitting device 20. The melt mass flow rate at 190°C of the material constituting the resin layer 60 may be 5.0 g / 10 min or less, 1.0 g / 10 min or less, or 0.50 g / 10 min or less. Such a resin layer 60 can suppress the generation of bubbles due to gas released from the light emitting substrate 30. In this example, the melt mass flow rate at 190°C of the material constituting the resin layer 60 may be 0.10 g / 10 min or more.

[0252] For a resin layer 60 used with a light emitting element 35 having low heat resistance, the composition for forming the resin layer 60 may contain a crosslinking agent in order to suppress flow during use of the light emitting device 20. The resin layer 60 may have a crosslinked structure, for example, by heating a composition containing a crosslinking agent. In other words, the resin layer 60 may contain a cured product of a curable resin composition. The resin layer 60 having a crosslinked structure can suppress the generation of bubbles due to gas released from the light emitting substrate 30.

[0253] In addition, the resin layer 60 used in combination with the light emitting element 35 having normal heat resistance can be set to have a high melting point. Therefore, as described above, the fluidity of the resin layer 60 at high temperatures can be improved. This effectively prevents the formation of voids between the resin layer 60 and the light emitting substrate 30 from which the light emitting element 35 protrudes.

[0254] 2H, the encapsulating sheet 50 may include a second resin layer 65 superimposed on the resin layer 60. The light emitting device 20 shown in FIG. 2H may be fabricated using the encapsulating sheet 50 shown in FIG. 8D. The encapsulating sheet 50 may include the resin layer 60 and the second resin layer 65 in this order from the light-incident side surface 51 toward the light-emitting side surface 52 in the first direction D1. In the illustrated example, the resin layer 60 is located between the light emitting substrate 30 and the second resin layer 65 in the first direction D1. Only the resin layer 60 is in contact with the light emitting substrate 30. The second resin layer 65 is not in contact with the light emitting substrate 30. In this example, by adjusting the residual crystallization amount at 100°C of the resin material constituting the resin layer 60 to 0.8 J / g or more as described above, the generation of bubbles due to gas released from the light emitting substrate 30 can be suppressed.

[0255] The physical properties of the second resin layer 65 may be determined from the viewpoint of improving the sealing function of the encapsulating sheet 50 for the light emitting elements 35.

[0256] For example, the melting point of the resin material constituting the second resin layer 65 may be higher than the melting point of the resin material constituting the resin layer 60. The melting point of the resin material constituting the second resin layer 65 may be 65°C or higher, 90°C or higher, or 100°C or higher. The melting point of the resin material constituting the second resin layer 65 may be 145°C or lower, 130°C or lower, or 120°C or lower.

[0257] Furthermore, the melt mass flow rate at 190°C of the material constituting the second resin layer 65 may be smaller than the melt mass flow rate at 190°C of the material constituting the resin layer 60. The melt mass flow rate at 190°C of the material constituting the second resin layer 65 may be 10 g / 10 min or less, 7.0 g / 10 min or less, or 5.0 g / 10 min or less. The melt mass flow rate at 190°C of the material constituting the second resin layer 65 may be 0.50 g / 10 min or more, 1.0 g / 10 min or more, or 3.0 g / 10 min or more.

[0258] <Experiment on the second aspect> Here, an experiment will be described in which the influence of the luminance ratio on the display image of the light emitting device constituting the dot matrix display device was investigated, but the present embodiment is not limited to the following experiment.

[0259] (Configurations and manufacturing methods of Examples and Comparative Examples) Light-emitting devices according to Examples B1 to B4 and Comparative Examples B1 and B2 were fabricated. The size of the light-emitting device was 5 cm x 5 cm in plan view. The light-emitting device included, from the second side to the first side in the first direction D1, a light-emitting substrate and a sealing sheet. The fabricated light-emitting device had a configuration in which the transparent plate was removed from the light-emitting device shown in Figures 1 and 2A. The configurations of Examples B1 to B4 and Comparative Examples B1 and B2 were identical to each other except for the sealing sheet. That is, Examples B1 to B4 and Comparative Examples B1 and B2 included the same light-emitting substrate. The light-emitting substrate used in Examples B1 to B4 and Comparative Examples B1 and B2 was the same as the light-emitting substrate used in the above-mentioned Examples A1 to A4 and Comparative Example A1.

[0260] The encapsulating sheet was composed only of a resin layer. As shown in FIG. 4, the resin layer included a first portion as a skin layer, a second portion as a core layer, and a third portion as a skin layer. The first portion, second portion, and third portion were located in this order from the light-incident side surface to the light-emitting side surface in the first direction D1. The first portion constituted the light-incident side surface. The third portion constituted the light-emitting side surface.

[0261] The resin layer including the first to third portions was produced by co-extrusion molding. For the co-extrusion molding, an apparatus including a 300 mm wide T-die was used. For the production of the first to third portions, an extruder with a screw diameter of φ30 mm was used. The raw material composition was heated to 210°C and extrusion molded. The thickness ratio of the first portion, the second portion, and the third portion was 1:6:1. The total thickness of the resin layer including the first to third portions was 200 μm.

[0262] The compositions used to prepare the first to third parts are shown in Table 2. Details of the resin components and additives in Table 2 are as follows. Silane-modified resin 1 (silane-modified polyolefin resin): density 0.902 g / cm 3 , melting point 90℃, melt mass flow rate (MFR) at 190℃ 1.0g / 10min M-LLDPE1 (metallocene-based linear low-density polyethylene): Density 0.880 g / cm 3 , melting point 60℃, melt mass flow rate (MFR) at 190℃ 3.5g / 10min M-LLDPE2 (metallocene-based linear low-density polyethylene): Density 0.901 g / cm 3 , melting point 93℃, melt mass flow rate (MFR) at 190℃ 2.0g / 10min LDPE (low density polyethylene): density 0.919g / cm 3 Melting point: 106°C, Melt mass flow rate (MFR) at 190°C: 3.5g / 10min Weatherproofing batch MB (weatherproofing masterbatch): density 0.880 g / cm 3A masterbatch was obtained by mixing 100 parts by mass of powder obtained by pulverizing the Ziegler linear low-density polyethylene described above with 3.8 parts by mass of a benzophenol-based ultraviolet absorber, 5 parts by mass of a hindered amine-based light stabilizer, and 0.5 parts by mass of a phosphorus-based heat stabilizer, melting and kneading the mixture, and then pelletizing the mixture.

[0263] Next, the encapsulating sheet made of a resin layer and the light emitting substrate were integrated by heating and pressing to obtain light emitting devices 20 according to Examples B1 to B4 and Comparative Examples B1 and B2. In the obtained light emitting devices, a plurality of light emitting elements were disposed between the wiring substrate and the encapsulating sheet. A vacuum laminator was used to integrate the light emitting substrate and the encapsulating sheet.

[0264] When the light emitting substrate and the sealing sheet were integrated, a glass plate and a resin film were placed on both sides of the light emitting substrate and the sealing sheet to ensure a uniform thickness. That is, a laminate was prepared in the following order: glass plate / resin film / light emitting substrate (wiring substrate / light emitting element) / sealing sheet / resin film / glass plate. The thickness of the glass plate was 3 mm. The resin film was an ETFE (tetrafluoroethylene-ethylene copolymer) film. The thickness of the resin film was 100 μm.

[0265] The light emitting substrate 30 and the encapsulating sheet 50 were integrated in the following manner. First, the laminate to be processed was placed in a vacuum laminator. The pressure inside the vacuum laminator was reduced over 5.0 minutes. The pair of glass plates of the laminate were pressed toward each other. The applied pressure was increased from 0 kPa to 100 kPa over 5 seconds, and then the applied pressure of 100 kPa was maintained for 7.0 minutes. The temperature inside the vacuum laminator was maintained at 150°C from before the laminate was placed until the laminate was removed.

[0266] The laminate was removed from the vacuum laminator and cooled under the following "Condition 1". Condition 1: The laminate was removed from the vacuum laminator and placed on a 1 cm thick iron plate, and cooled to 25°C over 6 minutes.

[0267] Thereafter, the resin film and the glass plate were removed from the laminate, thereby obtaining light emitting devices according to Examples B1 to B4 and Comparative Examples B1 and B2.

[0268] (Evaluation of Examples and Comparative Examples) For the encapsulating sheets used in each example, the amount of residual crystallinity at 100°C of the resin material constituting the resin layer was measured. The method for calculating the amount of residual crystallinity at 100°C was as described above. That is, the amount of residual crystallinity at 100°C is the sum of the endothermic heat values ​​measured at each integer temperature between 100°C and 200°C. The endothermic heat values ​​at each integer temperature are determined from the differential scanning calorimetry (DSC) curve. A Shimadzu DSC-60 differential scanning calorimeter was used for the differential scanning calorimetry. The amount of residual crystallinity at 100°C determined for each example is shown in Table 2.

[0269] The light emitting device according to each example was placed in an oven. Inside the oven, the light emitting element of the light emitting device was maintained in an emitting state. The temperature of the light emitting element placed in the oven was maintained at 100°C with the light emitting element turned on. The light emitting device was placed in the oven maintained at 100°C for 1000 hours. After being kept in the oven for 1000 hours, the light emitting device was removed from the oven. The light emitting element was turned on and off to check for the presence or absence of air bubbles. The light emitting device according to each example was evaluated according to the following criteria. The evaluation results are shown in Table 2. "C": No bubbles were found. "D": Bubbles were found that caused poor appearance

[0270] [Table 2]

[0271] <<Third Aspect>> The sealing sheet 50 according to the third embodiment can sufficiently suppress the permeation of moisture and oxygen.

[0272] The light-emitting element 35, which is an electronic device, and the wiring 42X of the wiring layer 42 included in the wiring substrate 40 may corrode due to contact with moisture such as water vapor. The light-emitting element 35 and the wiring 42X of the wiring layer 42 may also deteriorate due to oxidation caused by oxygen. Corrosion due to moisture and deterioration due to oxidation have an adverse effect on long-term reliability.

[0273] 8E , the encapsulating sheet 50 according to the third embodiment includes a resin layer 60 containing an olefin-based resin as a base resin, and an inorganic oxide layer 71 stacked on the resin layer 60. The encapsulating sheet 50 may include the resin layer 60 and the inorganic oxide layer 71 in this order from the light-incident side surface 51 to the light-emitting side surface 52 in the first direction D1. The resin layer 60 may be located between the light-emitting substrate 30 and the inorganic oxide layer 71 in the first direction D1.

[0274] (inorganic oxide layer) The inorganic oxide layer 71 has gas barrier properties. The inorganic oxide layer 71 has barrier properties against water vapor and oxygen. When the encapsulating sheet 50 includes the inorganic oxide layer 71, the light emitting substrate 30 covered by the encapsulating sheet 50 can be prevented from being exposed to gases such as water vapor and oxygen. This can prevent corrosion of the light emitting elements 35 and the wiring layer 42 due to moisture and deterioration of the light emitting elements 35 and the wiring layer 42 due to oxidation. The operational reliability of the light emitting device 20 can be improved even when the light emitting device 20 is used for a long period of time.

[0275] Examples of inorganic compounds constituting the inorganic oxide layer 71 include oxides, oxynitrides, oxycarbides, and oxycarbonitrides of metal or nonmetal elements. Examples of metal or nonmetal elements include silicon, aluminum, magnesium, calcium, potassium, tin, sodium, titanium, boron, yttrium, zirconium, cerium, and zinc. Examples of inorganic compounds constituting the inorganic oxide layer 71 include inorganic oxides such as silicon oxides (e.g., SiO2), aluminum oxides (e.g., Al2O3), magnesium oxide, titanium oxide, tin oxide, silicon-zinc alloy oxides, indium alloy oxides, silicon nitride, aluminum nitride, titanium nitride, silicon oxide nitride, and zinc silicon oxide. To impart excellent water vapor barrier properties to the inorganic oxide layer 71, the inorganic oxide layer 71 may contain one or more of aluminum oxide (alumina), silicon oxide (silica), and silicon carbide oxide. The inorganic oxide layer 71 may contain a single type of inorganic compound. The inorganic oxide layer 71 may contain two or more types of inorganic compounds. The resin layer 60 may include a plurality of inorganic oxide layers 71. The plurality of inorganic oxide layers 71 included in the resin layer 60 may be integrated into a multilayer structure.

[0276] The inorganic oxide layer 71 may be a vapor deposition layer formed by a vapor deposition method. The inorganic oxide layer 71, which is a vapor deposition layer, may be formed by one vapor deposition or multiple vapor depositions. As the vapor deposition method, a physical vapor deposition method (PVD method) such as a vacuum vapor deposition method, a sputtering method, or an ion plating method may be used. As the vapor deposition method, a chemical vapor deposition method (CVD method) such as a plasma chemical vapor deposition method, a thermal chemical vapor deposition method, or a photochemical vapor deposition method may be used.

[0277] The inorganic oxide layer 71 may be a coating layer formed by a coating method, etc. The inorganic oxide layer 71 may be a transfer layer formed by transfer.

[0278] The thickness of the inorganic oxide layer 71 may be determined depending on the expected level of gas barrier property. A lower limit may be set for the thickness of the inorganic oxide layer 71 from the viewpoint of imparting sufficient gas barrier property to the inorganic oxide layer 71. The thickness of the inorganic oxide layer 71 may be 10 nm or more, 50 nm or more, or 100 nm or more.

[0279] From the viewpoint of imparting sufficient flexibility to the inorganic oxide layer 71, an upper limit may be set on the thickness of the inorganic oxide layer 71. By setting an upper limit on the thickness of the inorganic oxide layer 71, it is possible to prevent cracks from occurring in the inorganic oxide layer 71 and barrier breakdown from occurring. From the viewpoint of imparting transparency to the inorganic oxide layer 71, an upper limit may be set on the thickness of the inorganic oxide layer 71. Light from the light emitting substrate 30 can pass through the transparent inorganic oxide layer 71. The thickness of the inorganic oxide layer 71 may be 500 nm or less, 300 nm or less, or 100 nm or less.

[0280] 8E, the encapsulating sheet 50 may include a support film 73. The support film 73 may function as a support material when forming the inorganic oxide layer 71. That is, the inorganic oxide layer 71 may be formed on the support film 73 by vapor deposition.

[0281] In the example shown in FIG. 8E , the encapsulating sheet 50 includes a resin layer 60 and an intermediate laminate 70. The resin layer 60 is located between the light emitting substrate 30 and the intermediate laminate 70 in the first direction D1. The intermediate laminate 70 includes a support film 73 and an inorganic oxide layer 71. The intermediate laminate 70 may be produced by forming the inorganic oxide layer 71 on the support film 73. The intermediate laminate 70 may be bonded to the resin layer 60. The intermediate laminate 70 may be bonded to the resin layer 60 by welding under heat and pressure. The intermediate laminate 70 may be bonded to the resin layer 60 using a bonding layer containing an adhesive or a pressure-sensitive adhesive.

[0282] (support film) The support film 73 may be transparent. Light from the light emitting substrate 30 can be transmitted through the transparent support film 73.

[0283] The support film 73 may be a resin film. The resin constituting the support film 73 may be a polyolefin resin such as polyethylene or polypropylene, a polyester resin such as polyethylene terephthalate (PET), polyethylene naphthalate (PEN), or polybutylene terephthalate (PBT), a cyclic polyolefin resin, a polystyrene resin, an acrylonitrile-styrene copolymer (AS resin), an acrylonitrile-butadiene-styrene copolymer (ABS resin), a poly(meth)acrylic resin, a polycarbonate resin, an ethylene-vinyl ester copolymer and a saponified product thereof, a polyamide resin such as various nylons, a polyimide resin, a polyurethane resin, an acetal resin, or a cellulose resin. The support film 73 may include a single type of resin film. The support film 73 may include two or more types of resin films.

[0284] From the viewpoint of transparency, stability, etc., the support film 73 may contain one or more of polyolefin and polyethylene terephthalate. The support film 73 may be a polyolefin film. The support film 73 may be a polyethylene terephthalate film. The support film 73 may contain a polyolefin film and a polyethylene terephthalate film.

[0285] The support film 73 may contain various plastic compounding agents, additives, etc. Examples of additives include lubricants, crosslinking agents, antioxidants, UV absorbers, light stabilizers, fillers, reinforcing agents, antistatic agents, pigments, and modifying resins.

[0286] The thickness of the support film 73 is not particularly limited. The thickness of the support film 73 may be 6 μm or more and 200 μm or less, or 9 μm or more and 100 μm or less. The support film 73 may be a single-layer film or a multilayer film including multiple layers. The multiple layers included in the multilayer film may contain different resin materials.

[0287] The support film 73 may include biomass material. The support film 73 may be used for radiocarbon dating. 14The support film 73 may include a biomass-derived polyolefin having a biomass degree calculated from a measurement of C. More specifically, the support film 73 may include a biomass-derived polyethylene having a biomass degree. The support film 73 may be used for radiocarbon dating. 14 The support film 73 may contain a biomass-derived polyester having a biomass degree calculated from the measured value of C. More specifically, the support film 73 may contain a biomass-derived polyethylene terephthalate having a biomass degree. By using a biomass material, the environmental load can be reduced.

[0288] The biomass degree of the support film 73 may be 5% or more, 25% or more, or 50% or more. There is no upper limit set for the biomass degree of the support film 73. The biomass degree of the resin layer 60 may be 100% or less, or may be less than 100%.

[0289] (barrier resin layer) 8F , the encapsulating sheet 50 may include a barrier resin layer 72. The barrier resin layer 72 may be located between the resin layer 60 and the inorganic oxide layer 71. The encapsulating sheet 50 may include, in this order from the light-incident side surface 51 to the light-emitting side surface 52 in the first direction D1, the resin layer 60, the barrier resin layer 72, and the inorganic oxide layer 71.

[0290] The barrier resin layer 72 has gas barrier properties. The barrier resin layer 72 has gas barrier properties. Since the encapsulating sheet 50 includes the barrier resin layer 72 in addition to the inorganic oxide layer 71, it is possible to more effectively prevent the light emitting substrate 30 covered by the encapsulating sheet 50 from being exposed to gases such as water vapor and oxygen. This makes it possible to prevent corrosion of the light emitting elements 35 and the wiring layer 42 due to moisture and deterioration of the light emitting elements 35 and the wiring layer 42 due to oxidation. It is possible to further improve the operational reliability of the light emitting device 20 even when the light emitting device 20 is used for a long period of time.

[0291] The barrier resin layer 72 may contain a gas barrier resin. The gas barrier resin is a resin that has gas barrier properties. Examples of gas barrier resins include ethylene-vinyl alcohol copolymer (EVOH), polyvinyl alcohol (PVA), polyacrylonitrile, polyamide, polyester, polyurethane, and (meth)acrylic resin. Examples of polyamides include nylon 6, nylon 6,6, and polymetaxylylene adipamide (MXD6).

[0292] The barrier resin layer 72 may contain one or more of polyvinyl alcohol and ethylene-vinyl alcohol copolymer. Polyvinyl alcohol and ethylene-vinyl alcohol copolymer are hydrophilic resins containing hydrophilic groups. Polyvinyl alcohol and ethylene-vinyl alcohol copolymer have excellent oxygen barrier properties. Polyvinyl alcohol and ethylene-vinyl alcohol copolymer also have excellent gas barrier properties, water resistance, and weather resistance.

[0293] The barrier resin layer 72 may be a layer containing either polyvinyl alcohol or an ethylene-vinyl alcohol copolymer as a main component. A layer containing either polyvinyl alcohol or an ethylene-vinyl alcohol copolymer as a main component is a layer in which either polyvinyl alcohol or an ethylene-vinyl alcohol copolymer is contained in the largest amount. The barrier resin layer 72 may contain 50% by mass or more of either polyvinyl alcohol or an ethylene-vinyl alcohol copolymer. The content of either polyvinyl alcohol or an ethylene-vinyl alcohol copolymer in the barrier resin layer 72 may be 60% by mass or more, 70% by mass or more, 80% by mass or more, or 90% by mass or more.

[0294] There is no particular upper limit set for the content of either polyvinyl alcohol or ethylene-vinyl alcohol copolymer in the barrier resin layer 72. The content of either polyvinyl alcohol or ethylene-vinyl alcohol copolymer in the barrier resin layer 72 may be 100% by mass or less, or 95% by mass or less.

[0295] The oxygen barrier property of the barrier resin layer 72 can be reduced by exposure to water vapor. In the example shown in FIG. 8F, the barrier resin layer 72 is located between an inorganic oxide layer 71, which has water vapor barrier property, and the light emitting substrate 30, which is protected from gas. The inorganic oxide layer 71 prevents the barrier resin layer 72 from being exposed to water vapor. According to the example shown in FIG. 8F, deterioration of the oxygen barrier property of the barrier resin layer 72 is prevented. The oxygen barrier property of the barrier resin layer 72 is stably maintained even during long-term use.

[0296] Polyvinyl alcohol can be obtained by saponifying polyvinyl acetate. The barrier resin layer 72 may contain, as polyvinyl alcohol, one or more of a partially saponified polyvinyl alcohol resin in which several tens of percent of acetate groups remain, a fully saponified polyvinyl alcohol in which no acetate groups remain, and a modified polyvinyl alcohol resin in which OH groups have been modified.

[0297] The ethylene-vinyl alcohol copolymer may be a saponified copolymer of ethylene and vinyl acetate, i.e., a compound obtained by saponifying an ethylene-vinyl acetate random copolymer. The ethylene-vinyl alcohol copolymer is not particularly limited. Examples of the ethylene-vinyl alcohol copolymer include partially saponified copolymers in which several tens of mol% of acetate groups remain, and completely saponified copolymers in which only a few mol% of acetate groups remain, or in which no acetate groups remain. From the viewpoint of gas barrier properties, the degree of saponification may be 80 mol% or more, 90 mol% or more, or 95 mol% or more. The content of repeating units derived from ethylene in the ethylene-vinyl alcohol copolymer (also referred to as the "ethylene content") may be 0 mol% or more and 50 mol% or less, or 20 mol% or more and 45 mol% or less.

[0298] The barrier resin layer 72 may be a barrier coat layer formed by coating. The barrier resin layer 72 as a barrier coat layer can be produced by the following method. First, a barrier composition to be used for forming the barrier resin layer 72 is prepared. Next, the barrier composition is applied. The method for applying the barrier composition is not particularly limited. The method for applying the barrier composition may be roll coating using a gravure roll coater or the like, spray coating, spin coating, or the like.

[0299] The coated barrier composition is then dried. During drying, polycondensation of polyvinyl alcohol or ethylene-vinyl alcohol copolymer proceeds, forming a coating film of the barrier composition. The coating film may be formed multiple times. Next, the coating film is heat-treated to obtain the barrier resin layer 72.

[0300] 8F , the encapsulant sheet 50 includes a resin layer 60 and an intermediate laminate 70. The intermediate laminate 70 includes a support film 73, an inorganic oxide layer 71, and a barrier resin layer 72, in this order. The barrier resin layer 72, the inorganic oxide layer 71, and the support film 73 are located in this order from the light-incident side surface 51 to the light-emitting side surface 52 in the first direction D1. The barrier resin layer 72 is configured as a part of the intermediate laminate 70. The intermediate laminate 70 shown in FIG. 8F can be produced by forming the inorganic oxide layer 71 on the support film 73 by vapor deposition, and then applying a barrier composition on the inorganic oxide layer 71 to form the barrier resin layer 72.

[0301] The illustrated intermediate laminate 70 may be bonded to the resin layer 60. The intermediate laminate 70 may be bonded to the resin layer 60 by welding under heat and pressure. The intermediate laminate 70 may also be bonded to the resin layer 60 using a bonding layer containing an adhesive or pressure-sensitive adhesive.

[0302] The inorganic oxide layer 71 is prone to cracking due to deformation such as bending or impact. If cracks occur in the inorganic oxide layer 71, the barrier properties of the inorganic oxide layer 71 are impaired. By forming a barrier resin layer 72 as a coating layer on the inorganic oxide layer 71, the adhesion between the inorganic oxide layer 71 and the barrier resin layer 72 can be improved. The barrier resin layer 72 in close contact with the inorganic oxide layer 71 can suppress cracking of the inorganic oxide layer 71.

[0303] The barrier resin layer 72 may contain at least one resin composition such as a hydrolyzate of a metal alkoxide or a hydrolyzed condensate of a metal alkoxide obtained by polycondensing a mixture of a metal alkoxide and a water-soluble polymer by a sol-gel method in the presence of a sol-gel catalyst, water, an organic solvent, etc. By providing such a barrier resin layer 72 on the inorganic oxide layer 71 formed by vapor deposition, cracking of the inorganic oxide layer 71 can be suppressed.

[0304] The thickness of the barrier resin layer 72 may be determined depending on the expected level of gas barrier properties. The thickness of the barrier resin layer 72 may be 0.01 μm or more, 0.1 μm or more, or 1 μm or more. The thickness of the barrier resin layer 72 may be 10 μm or less, 5 μm or less, or 1 μm or less.

[0305] (Water vapor permeability) According to the sealing sheet 50 of the third embodiment, the water vapor permeability g / (m 2 The water vapor permeability of the sealing sheet 50 is 0.3 g / (m 2 24h) or less is acceptable, 0.1g / (m 2 24h) or less is acceptable, 0.01g / (m 2 The water vapor permeability is a value measured in an environment with a temperature of 40°C and a relative humidity difference of 90% RH in accordance with JIS K7129-2:2019. The encapsulating sheet 50 is placed in a measuring device so that the light-emitting side surface 52 faces the hydrogen supply side. The water vapor permeability measuring device may be a PERMATRAN-w 3 / 33 manufactured by MOCON, USA.

[0306] (oxygen permeability) According to the sealing sheet 50 of the third embodiment, the oxygen permeability of the sealing sheet 50 is cc / (m 2 The oxygen permeability of the sealing sheet 50 is 0.3 cc / (m 2 ·day·atm) or less is acceptable, and 0.2cc / (m 2 ·day·atm) or less, and 0.1) cc / (m 2 The oxygen permeability may be less than 1 / 2 day atm. The oxygen permeability is a value measured in accordance with JIS K7126-2:2006 "Appendix A (Regulations): Test method for oxygen gas permeability using an electrolytic sensor" under conditions of a temperature of 23°C and a relative humidity difference of 90% RH. The encapsulating sheet 50 is placed in a measuring device with the light-emitting side surface 52 facing the oxygen supply side. The oxygen permeability measuring device may be an "OX-TRAN 2 / 20" manufactured by MOCON, USA.

[0307] For example, as described in JP 2020-49942 A, a combination of an inorganic oxide layer and a barrier resin layer can achieve a water vapor permeability of 0.3 g / (m 2 24h) or less and oxygen permeability 0.3cc / (m 2 ·day·atm) or less can be achieved.

[0308] The inorganic oxide layer 71 described in the third embodiment can be applied to the first and second embodiments. The barrier resin layer 72 described in the third embodiment can be applied to the first and second embodiments. The intermediate laminate 70 described in the third embodiment can be applied to the first and second embodiments. [Explanation of symbols]

[0309] D1: first direction, D2: second direction, D3: third direction, 10: display device, 12: display panel, 15: surface light source device, 15a: light emitting surface, 18: optical member, 20: light emitting device, 28: transparent plate, 29: surface layer, 30: light emitting substrate, 30E: element light emitting substrate, 35: light emitting element, 35A: light emitting element body, 35B: cover, 36: light emitting surface, 40: wiring substrate, 41: base material, 42: wiring layer, 42X: wiring, 43: substrate light-shielding layer, 50: encapsulating sheet, 51: light-incident side surface, 52: light-emitting side surface, 60: resin layer, 60A: first portion, 60B: second portion, 60C: third portion, 65: second resin layer, 66: light-shielding layer, 67: reflective layer, 68: patterned light-shielding layer, 70: intermediate laminate, 71: inorganic oxide layer, 72: barrier resin layer, 73: support film

Claims

1. A light-emitting substrate; a sealing sheet overlapping the light emitting substrate in a first direction, the light emitting substrate includes a wiring substrate and a plurality of light emitting elements supported by the wiring substrate; the light-emitting element is located between the wiring board and the sealing sheet, the encapsulating sheet includes a light-entering side surface and a light-emitting side surface facing each other in the first direction, the light-emitting element includes a light-emitting surface facing the light-incident side surface, A light emitting device, wherein the ratio of the luminance at the light output side surface above one light emitting element to the luminance at the light emitting surface of the one light emitting element is 90% or more.

2. The light emitting device according to claim 1 , wherein the encapsulating sheet includes a resin layer having an olefin-based resin as a base resin.

3. 3. The light emitting device according to claim 2, wherein the resin material constituting said resin layer has a residual crystallization amount at 100° C. of 8.0 J / g or more.

4. A light-emitting substrate; a sealing sheet overlapping the light emitting substrate in a first direction, the light emitting substrate includes a wiring substrate and a plurality of light emitting elements supported by the wiring substrate; the light-emitting element is located between the wiring board and the sealing sheet, the encapsulating sheet includes a resin layer having an olefin-based resin as a base resin, The light-emitting device has a residual crystallinity at 100° C. of the material that constitutes the resin layer of 8.0 J / g or more.

5. The light-emitting device according to claim 3 , wherein the resin layer has a cross-linked structure.

6. the encapsulating sheet includes a second resin layer superimposed on the resin layer, the resin layer is located between the light emitting substrate and the second resin layer, 5. The light emitting device according to claim 3, wherein the melting point of the resin material constituting the second resin layer is higher than the melting point of the resin material constituting the resin layer.

7. The encapsulating sheet includes a light-shielding layer, the light-shielding layer is located between the light-emitting substrate and the resin layer, 5. The light emitting device according to claim 2, wherein the light blocking layer is positioned between the plurality of light emitting elements.

8. the encapsulating sheet includes a reflective layer, the reflective layer is located between the light emitting substrate and the resin layer, 5. The light emitting device according to claim 2, wherein the reflective layer is located between the plurality of light emitting elements.

9. the encapsulating sheet includes a light-shielding layer located between the resin layer and the reflective layer, The light emitting device according to claim 8 , wherein the light blocking layer and the reflective layer are located between the plurality of light emitting elements.

10. 5. The light emitting device according to claim 2, wherein the resin layer has a transmission haze of 15% or less.

11. 5. The light emitting device according to claim 2, wherein the resin layer has a total light transmittance of 85% or more.

12. 5. The light emitting device according to claim 2, wherein the refractive index of the material forming said resin layer is 1.41 or more and 1.58 or less.

13. 5. The light emitting device according to claim 2, wherein the melting point of the resin material constituting said resin layer is 50° C. or higher and 145° C. or lower.

14. 5. The light emitting device according to claim 2, wherein the melt mass flow rate of the material constituting said resin layer at a temperature of 190° C. is 0.50 g / 10 min or more and 40 g / 10 min or less.

15. The density of the resin material constituting the resin layer is 0.875 g / cm ３ 0.930g / cm or more ３ The light emitting device according to any one of claims 2 to 4, wherein:

16. the encapsulating sheet includes an inorganic oxide layer superimposed on the resin layer, 5. The light emitting device according to claim 2, wherein the resin layer is located between the light emitting substrate and the inorganic oxide layer.

17. A light-emitting substrate; a sealing sheet overlapping the light emitting substrate in a first direction, the light emitting substrate includes a wiring substrate and a plurality of light emitting elements supported by the wiring substrate; the light-emitting element is located between the wiring board and the sealing sheet, the encapsulating sheet includes a resin layer having an olefin-based resin as a base resin, and an inorganic oxide layer superimposed on the resin layer, The resin layer is located between the light emitting substrate and the inorganic oxide layer.

18. The light emitting device according to claim 16 , wherein the encapsulating sheet further includes a barrier resin layer located between the inorganic oxide layer and the resin layer.

19. The water vapor permeability of the encapsulating sheet is 0.3 g / (m ２ 17. The light-emitting device according to claim 16, wherein the light-emitting period is equal to or less than 24 hours.

20. The oxygen permeability of the sealing sheet is 0.3 cc / (m ２ 17. The light emitting device according to claim 16, wherein the light emitting temperature is 1000°C / 2000°F (day atm) or less.

21. The light emitting device according to claim 16 , wherein the resin layer has an olefin-based resin as a base resin.

22. 22. The light emitting device according to claim 21, wherein the olefin-based resin includes one or more of polyethylene, polypropylene, a cyclic olefin copolymer, and an ethylene copolymer.

23. The light emitting device of claim 16 , wherein the resin layer comprises a biomass material.

24. 17. The light emitting device of claim 16, wherein the inorganic oxide layer comprises a vapor-deposited film containing one or more of silica, silicon carbide oxide, and alumina.

25. the encapsulating sheet includes a support film superimposed on the inorganic oxide layer, the inorganic oxide layer is located between the support film and the resin layer, 17. The light emitting device of claim 16, wherein the support film comprises one or more of a polyolefin and a polyethylene terephthalate.

26. 26. The light emitting device of claim 25, wherein the support film comprises a biomass material.

27. An encapsulating sheet for use in the light emitting device according to any one of claims 1 to 4 and 17.

28. An encapsulating sheet for encapsulating a light-emitting element, A resin layer having an olefin-based resin as a base resin is provided, The encapsulating sheet, wherein the material constituting the resin layer has a residual crystallinity at 100°C of 8.0 J / g or more.

29. An encapsulating sheet for encapsulating a light-emitting element, a resin layer having a thermoplastic resin as a base resin; an inorganic oxide layer superimposed on the resin layer.

30. 30. The encapsulating sheet according to claim 29, further comprising a barrier resin layer located between the inorganic oxide layer and the resin layer.

31. An encapsulating sheet for encapsulating a light-emitting element, The water vapor permeability is 0.3 g / (m ２ - 24h) or less.

32. An encapsulating sheet for encapsulating a light-emitting element, The oxygen permeability is 0.3 cc / (m ２ .day.atm) or less.

33. The encapsulating sheet according to any one of claims 29 to 32, wherein a transmission haze is 8% or less.

34. A surface light source device comprising the light emitting device according to any one of claims 1 to 4 and 17.

35. The surface light source device according to claim 34; A liquid crystal display device comprising the surface light source device and a display panel superimposed thereon.

Images