Optical laminate

Abstract

An object of the present invention is to provide an optical laminate suitable for manufacturing a self-luminous display device such as a Mini / Micro LED display device that improves the anti-reflection function and contrast of metal wirings while improving the luminous efficiency. Another object of the present invention is to reduce the number of processes and necessary components in the manufacturing process of the above self-luminous display device. The optical laminate (10) of the present invention has a laminated structure in which a first adhesive layer (1), a second adhesive layer (2), and a substrate (3) are laminated in sequence. The visible light transmittance T1 of the first adhesive layer (1) and the visible light transmittance T2 of the second adhesive layer (2) satisfy T1 < T2. Preferably, the visible light transmittance T1 of the first adhesive layer (1) and the visible light transmittance T3 of the substrate (3) satisfy T1 < T3.

Description

[0001] This application is a divisional application of an application with an application date of March 26, 2021, an application number of 202180026276.5, and an invention title of "Optical laminate". Technical Field

[0002] The present invention relates to an optical laminate suitable for encapsulating light-emitting elements of self-luminous display devices such as Mini / Micro LEDs. Background Art

[0003] In recent years, as a next-generation display device, a self-luminous display device represented by a Mini / Micro LED display device (Mini / Micro Light Emitting Diode Display) has been designed. As a basic configuration, a Mini / Micro LED display device uses a substrate on which a plurality of tiny LED light-emitting elements (LED chips) are densely arranged as a display panel. The LED chips are encapsulated with a packaging material, and a covering member such as a resin film or a glass plate is laminated on the outermost layer.

[0004] Self-luminous display devices such as Mini / Micro LED display devices have several modes such as a white backlight mode, a white light-emitting color filter mode, and an RGB mode. In the white light-emitting color filter mode and the RGB mode, in order to prevent reflection of metal wirings, metal oxides such as ITO, etc. disposed on the substrate of the display panel, a black packaging material may be used (for example, see Patent Documents 1 to 3). Among them, in an RGB-mode Mini / Micro LED display device in which LED chips are arranged, the above-mentioned black packaging material can also help prevent color mixing of RGB and improve contrast.

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2019-204905

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2017-203810

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 2018-523854 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] In the case of using the aforementioned black encapsulation material, since the upper part (image display side) of a light-emitting element such as an LED chip is covered with the black encapsulation material with a reduced visible light transmittance, there are problems of reduced luminous efficiency and a darkened image. To address this problem, when increasing the output power of the LED chip to increase the luminous brightness, there is also a problem of increased power consumption.

[0012] In the case of increasing the visible light transmittance of the black encapsulation material to improve the luminous efficiency, there is a trade-off relationship such that the antireflection function of the aforementioned metal wiring, etc., the prevention of color mixing of RGB, and the contrast will be reduced, and it is a difficult problem to balance them.

[0013] On the other hand, as the aforementioned black encapsulation material, a liquid curable resin or an adhesive containing a black colorant (dye, pigment) is being used. In the case of using a liquid curable resin containing a black colorant, there is a problem of uneven blackness due to uneven thickness. In addition, compared with dyes, pigments are more often selected because of their excellent heat resistance and weather resistance. However, in the case of using a liquid curable resin in which pigments are dispersed, on top of the aforementioned uneven thickness, there will also be problems such as uneven filling during filling of the liquid curable resin and uneven dispersion of the pigments during flow. Furthermore, since the surface of the liquid curable resin cured after encapsulation has no adhesion force, and furthermore, an adhesive or the like is required to laminate a covering member, there are also problems of more man-hours and components.

[0014] The present invention was conceived based on the above circumstances, and an object of the present invention is to provide an optical laminate suitable for manufacturing a self-luminous display device such as a Mini / Micro LED display device that improves the luminous efficiency and at the same time improves the antireflection function, contrast, etc. of metal wiring.

[0015] In addition, another object of the present invention is to reduce the number of processes and necessary components in the manufacturing process of the above self-luminous display device.

[0016] Means for Solving the Problems

[0017] The inventors of the present invention conducted in-depth research to achieve the aforementioned object, and as a result, found that by using an optical laminate obtained by laminating two adhesive layers with different transmittances and further laminating a substrate for manufacturing a self-luminous display device, it is possible to manufacture a self-luminous display device that combines improved luminous efficiency, antireflection function of metal wiring, etc., and contrast. It was also found that by using this optical laminate, the number of processes and necessary components can be reduced, and it is possible to efficiently manufacture a self-luminous display device with improved luminous efficiency, antireflection function of metal wiring, etc., and contrast. The present invention was completed based on these findings.

[0018] That is, a first aspect of the present invention provides an optical laminate having a laminated structure in which a first adhesive layer, a second adhesive layer, and a substrate are laminated in sequence, and the visible light transmittance T1 of the first adhesive layer and the visible light transmittance T2 of the second adhesive layer satisfy T1 < T2.

[0019] In the optical laminate of the first aspect of the present invention, the visible light transmittance T1 of the first adhesive layer and the visible light transmittance T2 of the second adhesive layer satisfy T1 < T2, that is, the scheme in which the visible light transmittance of the first adhesive layer is lower than that of the second adhesive layer is preferable in the following aspects: By using the optical laminate of the first aspect of the present invention in the manufacture of a self-luminous display device, the first adhesive layer can prevent reflection caused by metal wiring or the like on the display panel, prevent color mixing between the arranged light-emitting elements, and improve the contrast. In addition, this scheme is suitable in the following aspects: The configuration in which the second adhesive layer having a higher visible light transmittance than the first adhesive layer is located above the light-emitting element (image display side) can improve the light-emitting efficiency, make the image bright, and can reduce the power consumption caused by increasing the output power to improve the light-emitting brightness.

[0020] That is, by having this configuration, the optical laminate of the first aspect of the present invention can improve the light-emitting efficiency while solving the problems of anti-reflection function of metal wiring or the like, prevention of RGB color mixing, and improvement of contrast, which are in a trade-off relationship therewith.

[0021] In addition, by using the optical laminate of the first aspect of the present invention in the manufacture of a self-luminous display device, the laminated structure of the first adhesive layer and the second adhesive layer constitutes an encapsulation material for encapsulating the light-emitting elements arranged on the display panel, and the substrate constitutes the outermost surface covering member. Therefore, there is no need to laminate a covering member separately after encapsulation, the number of processes and necessary components can be reduced, and the manufacturing efficiency is improved.

[0022] Furthermore, the scheme in which the encapsulation material for encapsulating the light-emitting elements is an adhesive layer constituted by the laminated structure of the first adhesive layer and the second adhesive layer is suitable for the following reasons: When encapsulating the light-emitting elements with the adhesive layer in the manufacture of a self-luminous display device, it is not easy to generate the above-mentioned blackness unevenness caused by thickness unevenness, filling unevenness, pigment dispersion unevenness, etc. Furthermore, it can improve the anti-reflection of metal wiring or the like, prevention of RGB color mixing, and contrast.

[0023] In the optical laminate of the first aspect of the present invention, preferably, the visible light transmittance T1 of the first adhesive layer and the visible light transmittance T3 of the substrate satisfy T1 < T3. This scheme is preferable in terms of improving the above-mentioned light-emitting efficiency.

[0024] In the optical laminate according to the first aspect of the present invention, preferably, the visible light transmittance T1 of the aforementioned first adhesive layer is 80% or less. This solution is suitable for further improving the antireflection function of the above-mentioned metal wiring, etc., preventing color mixing of RGB, and improving the contrast. Further, preferably, the visible light transmittance T2 of the aforementioned second adhesive layer is 85 to 100%. This solution is suitable for further improving the above-mentioned luminous efficiency. That is, the visible light transmittance T1 of the aforementioned first adhesive layer being 80% or less and the visible light transmittance T2 of the aforementioned second adhesive layer being 85 to 100% are extremely suitable in the following aspects: while improving the luminous efficiency, it is possible to take into account the antireflection function of metal wiring, etc., which is in a trade-off relationship therewith, preventing color mixing of RGB, and improving the contrast.

[0025] In the optical laminate according to the first aspect of the present invention, preferably, the aforementioned first adhesive layer and the aforementioned second adhesive layer are adhesive layers formed of an adhesive composition selected from a photocurable adhesive composition and a solvent-based adhesive composition. Preferably, the adhesive composition forming the aforementioned first adhesive layer contains a colorant. These solutions are suitable in the following aspects: forming a solution where T1 and T2 satisfy T1 < T2, and further improving the above-mentioned luminous efficiency, the antireflection function of metal wiring, etc., preventing color mixing of RGB, and improving the contrast.

[0026] In the optical laminate according to the first aspect of the present invention, preferably, the aforementioned adhesive composition contains an acrylic polymer. Preferably, the aforementioned acrylic polymer contains a (meth)acrylic block copolymer. Preferably, the adhesive composition forming the aforementioned first adhesive layer is a solvent-based adhesive composition containing a (meth)acrylic block copolymer. These solutions are preferable in the following aspects: when the optical laminate according to the first aspect of the present invention is used for manufacturing a self-luminous display device, the aforementioned first adhesive layer and the aforementioned second adhesive layer (especially the first adhesive layer) fill the height difference of the light-emitting elements arranged on the display panel without gaps, and have excellent height difference absorbency and excellent processability.

[0027] In the optical laminate of the first aspect of the present invention, the thickness of the first adhesive layer is preferably 10 to 300 μm, more preferably 15 to 200 μm. The thickness of the second adhesive layer is preferably 1 to 500 μm, more preferably 10 to 300 μm, and further preferably 15 to 200 μm. The ratio of the thickness of the second adhesive layer to the thickness of the first adhesive layer (the thickness of the second adhesive layer / the thickness of the first adhesive layer) is preferably 1.0 to 5.0, more preferably 1.2 to 4.0, and further preferably 1.3 to 3.0. These schemes are preferred in the following aspects: by fully encapsulating the light-emitting elements arranged on the display panel of the self-luminous display device with the first adhesive layer, reflection of metal wiring, etc., and mixing of RGB are prevented, and contrast is improved, and by covering the upper part (image display side) of the light-emitting element with the second adhesive layer having high transmittance, the luminous efficiency can be improved.

[0028] In the optical laminate of the first aspect of the present invention, it is preferred that the surface of the substrate on which the second adhesive layer is not laminated is subjected to an anti-reflection treatment and / or an anti-glare treatment. Preferably, the anti-reflection treatment and / or the anti-glare treatment is an anti-glare layer provided on a single side of the substrate. Preferably, the anti-glare layer is formed using an anti-glare layer forming material comprising a resin, particles and a thixotropy imparting agent, and the anti-glare layer is aggregated by the particles and the thixotropy imparting agent, so that the surface of the anti-glare layer has an aggregated portion forming a convex portion. Preferably, in the convex portion on the surface of the anti-glare layer, the average inclination angle θa (°) is in the range of 0.1 to 5.0. These schemes are preferred in the following aspects: imparting an anti-reflection function and / or an anti-glare function to the surface of the optical laminate of the first aspect of the present invention, preventing a reduction in visibility caused by reflection of external light, image reflection, etc., and adjusting aesthetics such as glossiness.

[0029] The optical laminate of the first aspect of the present invention may further include a surface protection film laminated on the surface of the substrate not laminated with the second adhesive layer. This aspect is suitable for preventing damage and dirt from attaching during the manufacture, transportation, and shipment of the optical laminate and optical products including the optical laminate.

[0030] In addition, a second aspect of the present invention provides a self-luminous display device, which includes: a display panel having a plurality of light-emitting elements arranged on one side of a substrate, and the optical laminate of the first aspect of the present invention. The surface of the display panel on which the light-emitting elements are arranged is laminated with the first adhesive layer of the optical laminate. In the self-luminous display device of the second aspect of the present invention, the display panel may be an LED panel having a plurality of LED chips arranged on one side of a substrate. This solution is preferable in the following aspects: the self-luminous display device of the second aspect of the present invention can prevent reflection of metal wirings on the substrate, prevent color mixing of RGB, and improve contrast while improving luminous efficiency.

[0031] Effects of the Invention

[0032] By using the optical laminate of the present invention in the manufacture of a self-luminous display device, a self-luminous display device with improved luminous efficiency, antireflection function of metal wirings, etc., and contrast can be efficiently manufactured. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a schematic diagram (cross-sectional view) showing an embodiment of the optical laminate of the present invention.

[0034] Figure 2 It is a schematic diagram (cross-sectional view) showing another embodiment of the optical laminate of the present invention.

[0035] Figure 3 It is a schematic diagram (cross-sectional view) showing another embodiment of the optical laminate of the present invention.

[0036] Figure 4 It is a schematic diagram (cross-sectional view) showing an embodiment of the self-luminous display device (Mini / Micro LED display device) of the present invention.

[0037] Figure 5 It is a schematic diagram (cross-sectional view) showing another embodiment of the self-luminous display device (Mini / Micro LED display device) of the present invention.

[0038] Figure 6 It is a schematic diagram (cross-sectional view) showing another embodiment of the self-luminous display device (Mini / Micro LED display device) of the present invention.

[0039] Description of Reference Numerals

[0040] 10, 11, 12 Optical laminate

[0041] 1 First adhesive layer

[0042] 2 Second adhesive layer

[0043] 3 Substrate

[0044] 4 Anti-reflection treatment and / or anti-glare treatment

[0045] 4a Anti-glare layer

[0046] 20, 21, 22 Self-luminous display device (Mini / Micro LED display device)

[0047] 5 Substrate

[0048] 6 Metal wiring layer

[0049] 7 Light-emitting element (LED chip) Detailed implementation mode

[0050] The first aspect of the present invention provides an optical laminate. The optical laminate of the first aspect of the present invention has a laminated structure in which a first adhesive layer, a second adhesive layer, and a substrate are laminated in sequence. The visible light transmittance T1 of the aforementioned first adhesive layer and the visible light transmittance T2 of the aforementioned second adhesive layer satisfy T1 < T2.

[0051] "Optical" in the optical laminate of the first aspect of the present invention means being used in optical applications. More specifically, it means being used in the manufacture of products (optical products) using optical components. As optical products, for example, image display devices, input devices such as touchscreens, etc. can be cited. Preferably, self-luminous display devices such as Mini / Micro LED display devices and organic EL (electroluminescence) display devices, and in particular, it can be suitably used for manufacturing Mini / Micro LED display devices.

[0052] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings, but the present invention is not limited thereto and is merely illustrative.

[0053] Figures 1 to 3 It is a schematic diagram (cross-sectional view) showing an embodiment of the optical laminate of the first aspect of the present invention. Figures 4 to 6 It is a schematic diagram (cross-sectional view) showing an embodiment of the self-luminous display device (Mini / Micro LED display device) of the second aspect of the present invention.

[0054] In Figure 1 , the optical laminate 10 has a laminated structure in which a first adhesive layer 1, a second adhesive layer 2, and a substrate 3 are laminated in sequence. In Figure 2 , the optical laminate 11 has been subjected to an anti-reflection treatment and / or an anti-glare treatment 4 on the surface 3a of the substrate 3 where the second adhesive layer 2 is not laminated. In Figure 3In [the structure], an antiglare layer 4a is formed on the surface 3a of the substrate 3 where the second adhesive layer 2 is not laminated as an antireflection treatment and / or an antiglare treatment for the optical laminate 12.

[0055] In the present embodiment, the visible light transmittance T1 of the first adhesive layer 1 and the visible light transmittance T2 of the second adhesive layer 2 satisfy T1 < T2. That is, the visible light transmittance of the first adhesive layer 1 is lower than that of the second adhesive layer 2.

[0056] In Figure 4 [the structure], a self-emitting display device (Mini / Micro LED display device) 20 includes a display panel in which a plurality of LED chips 7 are arranged on one side of a substrate 5, and the optical laminate 10 of the first aspect of the present invention. The surface of the display panel on which the LED chips 7 are arranged is laminated with the first adhesive layer 1 of the optical laminate 10. In Figure 5 [the structure], a self-emitting display device (Mini / Micro LED display device) 21 has an antireflection treatment and / or an antiglare treatment 4 applied to the surface 3a of the substrate 3 where the second adhesive layer 2 is not laminated. In Figure 6 [the structure], a self-emitting display device (Mini / Micro LED display device) 22 forms an antiglare layer 4a on the surface 3a of the substrate 3 where the second adhesive layer 2 is not laminated as an antireflection treatment and / or an antiglare treatment.

[0057] In the present embodiment, a metal wiring layer 6 for sending a light emission control signal to each LED chip 7 is laminated on the substrate 5 of the display panel. Each LED chip 7 that emits light of various colors of red (R), green (G), and blue (B) is alternately arranged on the substrate 5 of the display panel via the metal wiring layer 6. The metal wiring layer 6 is formed of a metal such as copper, reflects the light emitted by each LED chip 7, and reduces the image recognition. In addition, the light emitted by each LED chip 7 of each color of RGB is mixed, and the contrast is reduced.

[0058] In the present embodiment, each LED chip 7 arranged on the display panel is encapsulated without a gap by the first adhesive layer 1 and the second adhesive layer 2. That is, the laminated structure of the first adhesive layer 1 and the second adhesive layer 2 can constitute the encapsulation material for each LED chip 7.

[0059] In the present embodiment, the first adhesive layer 1 encapsulates between the respective LED chips 7 arranged on the display panel and the metal wiring layer 6. By making the visible light transmittance of the first adhesive layer 1 lower than that of the second adhesive layer 2, sufficient light-shielding property is achieved in the visible light region. Since the first adhesive layer 1 with higher light-shielding property encapsulates between the respective LED chips 7 without gaps, color mixing between the respective LED chips 7 can be prevented, and the contrast can be improved. In addition, since the first adhesive layer 1 with higher light-shielding property also encapsulates the surface of the metal wiring layer 6, reflection caused by the metal wiring layer 6 can be prevented.

[0060] In the present embodiment, the second adhesive layer 2 encapsulates the upper part (display image side) of the respective LED chips 7 arranged on the display panel. By making the visible light transmittance of the second adhesive layer 2 higher than that of the first adhesive layer 1, sufficient transmittance is achieved in the visible light region. Since the second adhesive layer 2 with higher transmittance encapsulates the upper part (display image side) of the respective LED chips 7, absorption of visible light emitted from the respective LED chips 7 can be suppressed to a low level, the luminous efficiency can be improved, and thus the image can be made brighter. In addition, since there is no need to increase the output power to improve the luminous brightness, power consumption can be suppressed to a low level.

[0061] The Mini / Micro LED display device of the present embodiment can be manufactured by bonding a display panel having a plurality of LED chips arranged on one side of a substrate to the first adhesive layer of the optical laminate of the present embodiment. At this time, the base material 3 can constitute a covering member forming the outermost layer of the self-luminous display device (Mini / Micro LED display device). Therefore, according to the present embodiment, the process of separately installing a covering member can be omitted, the number of necessary components and processes can be reduced, and production efficiency can be improved.

[0062] In addition, in the Mini / Micro LED display device 21 of the present embodiment, an antireflection treatment and / or an antiglare treatment 4 is applied to the surface 3a of the base material 3, and in the Mini / Micro LED display device 22, an antiglare layer 4a is formed as an antireflection treatment on the surface 3a of the base material 3. The antireflection treatment and / or the antiglare treatment 4, particularly the antiglare layer 4a, prevents a reduction in recognizability caused by reflection of external light, image reflection, etc. at the surface 3a of the base material 3 serving as a covering member, and / or adjusts the aesthetics such as glossiness.

[0063] Hereinafter, each component will be described in detail.

[0064] <Base material>

[0065] In the present embodiment, the substrate 3 is not particularly limited, and examples thereof include glass, a transparent plastic film substrate, and the like. The transparent plastic film substrate is not particularly limited, and a substrate having excellent visible light transmittance and excellent transparency (preferably a substrate having a haze value of 5% or less) is preferred. Examples thereof include the transparent plastic film substrate described in Japanese Patent Application Laid-Open No. 2008-90263. As the transparent plastic film substrate, a substrate having little optical birefringence can be suitably used. In the present embodiment, the substrate 3 can also be used as a covering member of the self-luminous display device. In this case, as the transparent plastic film substrate, a film formed of triacetyl cellulose (TAC), polycarbonate, an acrylic polymer, a polyolefin having a cyclic or norbornene structure, or the like is preferred. Further, in the present embodiment, the substrate 3 can be the covering member itself. If such a solution is adopted, the process of separately laminating the covering member can be reduced in the manufacture of the self-luminous display device, so that the number of processes and necessary components can be reduced, and the production efficiency can be improved. Further, if such a solution is adopted, the covering member can be further thinned. It should be noted that when the substrate 3 is a covering member, the surface 3a constitutes the outermost surface of the self-luminous display device.

[0066] In the optical laminate of the present embodiment, preferably, the visible light transmittance T1 of the first adhesive layer 1 and the visible light transmittance T3 of the substrate 3 satisfy T1 < T3. This solution is suitable in the following aspects: forming a configuration in which the substrate 3 having a higher visible light transmittance than the first adhesive layer 1 is located above the light-emitting element (image display side), which can improve the light-emitting efficiency, make the image bright, and can reduce the power consumption caused by the increase in output power to improve the light-emitting brightness. The visible light transmittance T3 of the substrate 3 is not particularly limited, and is, for example, 85 to 100%, and can be 88% or more, 90% or more, or 92% or more.

[0067] In the present embodiment, the thickness of the substrate 3 is not particularly limited. For example, when considering workability such as strength and operability and thinness, etc., the range of 10 to 500 μm is preferred, the range of 20 to 300 μm is more preferred, and the range of 30 to 200 μm is most preferred. The refractive index of the substrate 3 is not particularly limited, and is, for example, in the range of 1.30 to 1.80, and preferably in the range of 1.40 to 1.70.

[0068] In the present embodiment, preferably, the surface 3a of the substrate 3 is subjected to a reflective surface treatment and / or an antiglare treatment 4. When the reflective surface treatment and / or the antiglare treatment 4 is performed on the surface 3a of the substrate 3, the surface 3a constitutes the outermost surface of the self-luminous display device, and can prevent the reduction in recognizability caused by the reflection of external light, image reflection, etc., or can adjust the aesthetics such as glossiness. An antiglare treatment that is easy to manufacture and has a low cost is preferred.

[0069] As the aforementioned antireflection treatment, a known antireflection treatment can be used without particular limitation. For example, antireflection (AR) treatment can be cited.

[0070] As the aforementioned antireflection (AR) treatment, a known AR treatment can be applied without particular limitation. Specifically, it can be implemented by forming an antireflection layer (AR layer) obtained by laminating two or more optical thin films with strictly controlled thickness and refractive index or the aforementioned optical thin films on one side 3a of the substrate 3. The aforementioned AR layer exhibits an antireflection function by canceling out the reversed phases of the incident light and the reflected light using the interference effect of light. The wavelength region of visible light rays exhibiting the antireflection function is, for example, 380 to 780 nm, and particularly the wavelength region with high visibility is in the range of 450 to 650 nm. Preferably, the AR layer is designed such that the reflectance at the center wavelength of 550 nm is minimized.

[0071] As the aforementioned AR layer, a multilayer antireflection layer having a structure in which two to five optical thin layers (thin films with strictly controlled thickness and refractive index) are laminated is generally cited. By forming multiple layers with different refractive indices only with a specified thickness, the degree of freedom in the optical design of the AR layer is increased, the antireflection effect can be further improved, and the spectral reflectance characteristics can be made uniform (flat) in the visible light region. In the aforementioned optical thin film, since high thickness accuracy is required, the formation of each layer is generally carried out by vacuum evaporation, sputtering, CVD, etc., which belong to the dry process.

[0072] As the aforementioned antiglare (AG) treatment, a known AG treatment can be applied without particular limitation. For example, it can be implemented by forming an antiglare layer 4a on the surface 3a of the substrate 3. As the aforementioned antiglare layer 4a, a known antiglare layer can be adopted without limitation, and it is generally formed as a layer in which inorganic or organic particles as antiglare agents are dispersed in a resin.

[0073] In the present embodiment, the antiglare layer 4a is formed using an antiglare layer forming material containing a resin, particles, and a thixotropy imparting agent. By the aggregation of the aforementioned particles and the aforementioned thixotropy imparting agent, convex portions are formed on the surface of the aforementioned antiglare layer 4a. According to this scheme, the antiglare layer 4a has excellent display characteristics that take into account both antiglare properties and prevention of white blurring. Moreover, although the antiglare layer is formed by utilizing the aggregation of particles, the generation of protrusions on the surface of the antiglare layer that would become appearance defects can be prevented, and the yield of the product can be improved.

[0074] Examples of the aforementioned resin include thermosetting resins and radiation curable resins that are cured by ultraviolet rays or light. As the aforementioned resin, commercially available thermosetting resins, ultraviolet curable resins, etc. can also be used.

[0075] As the aforementioned thermosetting resin and ultraviolet curable resin, for example, a curable compound having at least one group selected from acrylate group and methacrylate group and curable by heat, light (such as ultraviolet ray) or electron beam can be used. Examples thereof include: silicone resin, polyester resin, polyether resin, epoxy resin, urethane resin, alkyd resin, spiroacetal resin, polybutadiene resin, polythiol polyene resin, acrylate, methacrylate and other oligomers or prepolymers of polyfunctional compounds such as polyols. These can be used alone or in combination of two or more.

[0076]

[0076]

[0077] The particles for forming the antiglare layer 4a mainly function to make the surface of the formed antiglare layer 4a uneven to impart antiglare property and to control the haze value of the antiglare layer 4a. The haze value of the antiglare layer 4a can be designed by controlling the refractive index difference between the aforementioned particles and the aforementioned resin. Examples of the aforementioned particles include inorganic particles and organic particles. There is no particular limitation on the aforementioned inorganic particles. Examples thereof include: silica particles, titanium oxide particles, alumina particles, zinc oxide particles, tin oxide particles, calcium carbonate particles, barium sulfate particles, talc particles, kaolin particles, calcium sulfate particles, etc. In addition, there is no particular limitation on the aforementioned organic particles. Examples thereof include: polymethyl methacrylate resin powder (PMMA fine particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, polyvinyl fluoride resin powder, etc. These inorganic particles and organic particles can be used alone or in combination of two or more.

[0078] The weight average particle diameter (D) of the aforementioned particles is preferably in the range of 2.5 to 10 μm. By setting the weight average particle diameter of the aforementioned particles within the aforementioned range, for example, the anti-glare property becomes more excellent, and white blurring can be prevented. The weight average particle diameter of the aforementioned particles is more preferably in the range of 3 to 7 μm. It should be noted that the weight average particle diameter of the aforementioned particles can be measured, for example, by the Coulter counting method. For example, by using a particle size distribution measuring device (trade name: Coulter Particle Sizer, manufactured by Beckman Coulter, Inc.) that utilizes the pore resistance method, the resistance of the electrolyte equivalent to the volume of the particles when the particles pass through the aforementioned pores is measured, thereby measuring the number and volume of the aforementioned particles, and calculating the weight average particle diameter.

[0079] There is no particular limitation on the shape of the aforementioned particles. For example, they can be substantially spherical in the shape of beads, or amorphous particles such as powders. Preferably, they are substantially spherical particles, more preferably substantially spherical particles with an aspect ratio of 1.5 or less, and most preferably spherical particles.

[0080] Regarding the proportion of the aforementioned particles in the anti-glare layer 4a, relative to 100 parts by weight of the aforementioned resin, it is preferably in the range of 0.2 to 12 parts by weight, more preferably in the range of 0.5 to 12 parts by weight, and further preferably in the range of 1 to 7 parts by weight. By setting it within the aforementioned range, for example, the anti-glare property becomes more excellent, and white blurring can be prevented.

[0081] Examples of the thixotropy imparting agent used for forming the anti-glare layer 4a include: organic clay, oxidized polyolefin, modified urea, etc.

[0082] In order to improve the affinity with the aforementioned resin, the aforementioned organic clay is preferably an organically treated clay. As the organic clay, for example, layered organic clay can be cited. The aforementioned organic clay can be prepared by oneself or a commercially available product can be used. As the aforementioned commercially available products, for example, the following can be cited: LUCENTITE SAN, LUCENTITE STN, LUCENTITE SEN, LUCENTITE SPN, SOMASIF ME-100, SOMASIF MAE, SOMASIF MTE, SOMASIF MEE, SOMASIF MPE (trade names, all manufactured by Co-op Chemical Co., Ltd.); S-BEN, S-BEN C, S-BEN E, S-BEN W, S-BENP, S-BEN WX, S-BEN N-400, S-BEN NX, S-BEN NX80, S-BEN NO12S, S-BEN NEZ, S-BEN NO12, S-BEN NE, S-BEN NZ, S-BEN NZ70, ORGANITE, ORGANITE D, ORGANITE T (trade names, all manufactured by HOJUN Co., Ltd.); KUNIPIA F, KUNIPIA G, KUNIPIA G4 (trade names, all manufactured by KUNIMINE INDUSTRIES CO., LTD.); TIXOGEL VZ, CLAYTONE HT, CLAYTONE 40 (trade names, all manufactured by Rockwood Additives Ltd.), etc.

[0083] The aforementioned oxidized polyolefin can be prepared by oneself or a commercially available product can be used. As the aforementioned commercially available products, for example, the following can be cited: DISPARLON 4200-20 (trade name, manufactured by Kusumoto Chemicals, Ltd.), FLOWNON SA300 (trade name, manufactured by Kyoeisha Chemical Co., Ltd.), etc.

[0084] The aforementioned modified urea is a reaction product of an isocyanate monomer or its adduct and an organic amine. The aforementioned modified urea can be prepared by oneself or a commercially available product can be used. As the aforementioned commercially available products, for example, the following can be cited: BYK410 (manufactured by BYK Chemie), etc.

[0085] The aforementioned thixotropy imparting agent can be used alone or two or more kinds can be used in combination.

[0086] In the present embodiment, it is preferable that the height of the convex portion from the average roughness line of the antiglare layer 4a is less than 0.4 times the thickness of the antiglare layer 4a. More preferably, it is in the range of 0.01 times or more and less than 0.4 times, and further preferably in the range of 0.01 times or more and less than 0.3 times. If it is in this range, protrusions that become appearance defects can be appropriately prevented from forming on the convex portion. The antiglare layer 4a of the present embodiment can make appearance defects less likely to occur by having convex portions with such a height. Here, the height from the average line can be measured, for example, by the method described in Japanese Patent Application Laid-Open No. 2017-138620.

[0087] Regarding the proportion of the thixotropy-imparting agent in the antiglare layer 4a, it is preferably in the range of 0.1 to 5 parts by weight, and more preferably in the range of 0.2 to 4 parts by weight, based on 100 parts by weight of the resin.

[0088] There is no particular limitation on the thickness (d) of the antiglare layer 4a, and it is preferably in the range of 3 to 12 μm. By making the thickness (d) of the antiglare layer 4a within the above range, for example, curling of the optical laminate 12 can be prevented, and problems such as poor transportability and reduced productivity can be avoided. In addition, when the thickness (d) is within the above range, the weight average particle diameter (D) of the particles is as described above, and is preferably in the range of 2.5 to 10 μm. By combining the thickness (d) of the antiglare layer 4a and the weight average particle diameter (D) of the particles as described above, the antiglare property can be made more excellent. The thickness (d) of the antiglare layer 4a is more preferably in the range of 3 to 8 μm.

[0089] Regarding the relationship between the thickness (d) of the antiglare layer 4a and the weight average particle diameter (D) of the particles, it is preferably in the range of 0.3 ≤ D / d ≤ 0.9. With such a relationship, the antiglare property is more excellent, white blur can be prevented, and an antiglare layer without appearance defects can be formed.

[0090] As described above, in the optical laminate 12 of the present embodiment, the antiglare layer 4a is aggregated by the particles and the thixotropy-imparting agent, so that convex portions are formed on the surface of the antiglare layer 4a. At the aggregation portion where the convex portions are formed, the particles exist in a state where a plurality of them are aggregated in the plane direction of the antiglare layer 4a. Thus, the convex portions form a smooth shape. The antiglare layer 4a of the present embodiment can prevent white blur while maintaining the antiglare property, and further can make appearance defects less likely to occur by having convex portions with such a shape.

[0091] The surface shape of the antiglare layer 4a can be arbitrarily designed by controlling the aggregation state of the particles contained in the antiglare layer forming material. The aggregation state of the aforementioned particles can be controlled, for example, by the material of the aforementioned particles (such as the chemical modification state of the particle surface, the affinity for solvents and resins, etc.), the type and combination of the resin (binder) or solvent. Here, in the present embodiment, the aggregation state of the aforementioned particles can be controlled by the thixotropy imparting agent contained in the antiglare layer forming material. As a result, in the present embodiment, the aggregation state of the aforementioned particles can be as described above, and the aforementioned convex portions can be formed into a smooth shape.

[0092] In the optical laminate 12 of the present embodiment, when the substrate 3 is formed of a resin or the like, it is preferable to have a penetration layer at the interface between the substrate 3 and the antiglare layer 4a. The aforementioned penetration layer is formed by the resin component contained in the forming material of the antiglare layer 4a penetrating into the substrate 3. If a penetration layer is formed, the adhesion between the substrate 3 and the antiglare layer 4a can be improved, which is preferable. The thickness of the aforementioned penetration layer is preferably in the range of 0.2 to 3 μm, more preferably in the range of 0.5 to 2 μm. For example, when the substrate 3 is triacetyl cellulose and the resin contained in the antiglare layer 4a is an acrylic resin, the aforementioned penetration layer can be formed. The aforementioned penetration layer can be confirmed, for example, by observing the cross section of the optical laminate 12 with a transmission electron microscope (TEM), and the thickness can be measured.

[0093] Even when applied to the optical laminate 12 having such a penetration layer, the present embodiment can easily form a desired smooth surface uneven shape that takes into account both antiglare properties and prevention of white blurring. In the aforementioned penetration layer, the more the substrate 3 lacks adhesion to the antiglare layer 4a, the thicker it is preferably formed to improve the adhesion.

[0094] In the present embodiment, it is preferable that the average number of appearance defects having a maximum diameter of 200 μm or more in the antiglare layer 4a is 1 or less per 1 m 2 of the antiglare layer 4a. More preferably, there are no such appearance defects.

[0095] In the present embodiment, the substrate 3 on which the antiglare layer 4a is formed preferably has a haze value in the range of 0 to 10%. The aforementioned haze value refers to the haze value (haze) according to JIS K 7136 (2000 edition). The aforementioned haze value is more preferably in the range of 0 to 5%, and further preferably in the range of 0 to 3%. In order to make the haze value in the above range, it is preferable to select the aforementioned particles and the aforementioned resin so that the refractive index difference between the aforementioned particles and the aforementioned resin is in the range of 0.001 to 0.02. By making the haze value in the aforementioned range, a clear image can be obtained, and the contrast in the dark can also be improved.

[0096] Preferably, in the concavo-convex shape on the surface of the antiglare layer 4a, the average inclination angle θa (°) is in the range of 0.1 to 5.0, more preferably in the range of 0.3 to 4.5, still more preferably in the range of 1.0 to 4.0, and particularly preferably in the range of 1.6 to 4.0. Herein, the aforementioned average inclination angle θa is a value defined by the following mathematical formula (1). The aforementioned average inclination angle θa is a value measured, for example, by the method described in Japanese Patent Application Laid-Open No. 2017-138620.

[0097] Average inclination angle θa = tan-1Δa (1)

[0098] In the aforementioned mathematical formula (1), Δa is as shown in the following mathematical formula (2), and is a value obtained by dividing the sum (height h) of the differences between the peaks of adjacent mountains and the lowest points of valleys (h1 + h2 + h3... + hn) by the reference length L in the reference length L of the roughness curve defined in JIS B 0601 (1994 edition). The aforementioned roughness curve is a curve obtained by removing surface waviness components longer than a specified wavelength from a cross-sectional curve using a phase difference compensation type high-pass filter. In addition, the aforementioned cross-sectional curve refers to the contour that appears at the cut when the object surface is cut by a plane perpendicular to the object surface.

[0099] Δa = (h1 + h2 + h3... + hn) / L (2)

[0100] If θa is within the above range, the antiglare property is more excellent, and white blurring can be prevented.

[0101] When forming the antiglare layer 4a, it is preferable that the prepared antiglare layer forming material (coating liquid) exhibits thixotropy, and it is preferable that the specified Ti value is in the range of 1.3 to 3.5, more preferably in the range of 1.3 to 2.8.

[0102] Ti value = β1 / β2

[0103] Herein, β1 is the viscosity measured under the condition of a shear rate of 20 (1 / s) using RheoStress 6000 manufactured by HAAKE, and β2 is the viscosity measured under the condition of a shear rate of 200 (1 / s) using RheoStress 6000 manufactured by HAAKE.

[0104] If the Ti value is less than 1.3, appearance defects are likely to occur, and the antiglare property and the characteristics regarding white blurring deteriorate. In addition, if the Ti value exceeds 3.5, the aforementioned particles are difficult to aggregate, and a dispersed state is likely to be formed.

[0105] There is no particular limitation on the manufacturing method of the antiglare layer 4a of the present embodiment, and any method can be adopted. For example, an antiglare layer forming material (coating liquid) containing the aforementioned resin, the aforementioned particles, the aforementioned thixotropy imparting agent, and a solvent can be prepared, and the aforementioned antiglare layer forming material (coating liquid) is coated on the surface 3a of the aforementioned substrate 3 to form a coating film, and the aforementioned coating film is cured to form the antiglare layer 4a, thereby manufacturing. In the present embodiment, a method of imparting an uneven shape by an appropriate method such as a transfer method based on a mold, sandblasting, an embossing roll, etc. can also be used together.

[0106] There is no particular limitation on the aforementioned solvent, and various solvents can be used. One kind can be used alone, or two or more kinds can be used in combination. There is an optimal solvent type and solvent ratio according to the composition of the aforementioned resin, the types and contents of the aforementioned particles and the aforementioned thixotropy imparting agent. There is no particular limitation on the solvent. For example, alcohols such as methanol, ethanol, isopropanol, butanol, 2-methoxyethanol, etc.; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, etc.; esters such as methyl acetate, ethyl acetate, butyl acetate, etc.; ethers such as diisopropyl ether, propylene glycol monomethyl ether, etc.; glycols such as ethylene glycol, propylene glycol, etc.; cellosolves such as ethyl cellosolve, butyl cellosolve, etc.; aliphatic hydrocarbons such as hexane, heptane, octane, etc.; aromatic hydrocarbons such as benzene, toluene, xylene, etc. can be cited.

[0107] As the substrate 3, for example, when a permeation layer is formed of triacetyl cellulose (TAC), a good solvent for TAC can be suitably used. As this solvent, for example, ethyl acetate, methyl ethyl ketone, cyclopentanone, etc. can be cited.

[0108] In addition, by appropriately selecting the solvent, the thixotropy of the antiglare layer forming material (coating liquid) brought by the thixotropy imparting agent can be well exhibited. For example, when using organic clay, toluene and xylene can be suitably used alone or in combination. For example, when using oxidized polyolefin, methyl ethyl ketone, ethyl acetate, and propylene glycol monomethyl ether can be suitably used alone or in combination. For example, when using modified urea, butyl acetate and methyl isobutyl ketone can be suitably used alone or in combination.

[0109] Various leveling agents can be added to the aforementioned antiglare layer forming material. As the aforementioned leveling agent, for the purpose of preventing coating unevenness (uniformization of the coating surface), for example, fluorine-based or silicone-based leveling agents can be used. In the present embodiment, the leveling agent can be appropriately selected according to the case where antifouling property is required for the surface of the antiglare layer 4a, or the case where an antireflection layer (low refractive index layer), a layer containing an interlayer filler, etc. are to be formed on the antiglare layer 4a. For example, in the present embodiment, since the coating liquid can exhibit thixotropy by containing the aforementioned thixotropy imparting agent, coating unevenness is not easily generated. Therefore, for example, the present embodiment has the advantage of being able to expand the options of the aforementioned leveling agent.

[0110] Regarding the compounding amount of the foregoing leveling agent with respect to 100 parts by weight of the foregoing resin, it is, for example, 5 parts by weight or less, preferably in the range of 0.01 to 5 parts by weight.

[0111] In the foregoing antiglare layer forming material, pigments, fillers, dispersants, plasticizers, ultraviolet absorbers, surfactants, antifouling agents, antioxidants, etc. can be added as needed within a range not impairing the performance. These additives can be used alone or in combination of two or more.

[0112] In the foregoing antiglare layer forming material, for example, a conventionally known photoinitiator described in Japanese Patent Laid-Open No. 2008-88309 can be used.

[0113] As a method of coating the foregoing antiglare layer forming material on the surface 3a of the substrate 3, for example, coating methods such as injection coating method, die coating method, spin coating method, spray coating method, gravure coating method, roll coating method, bar coating method, etc. can be used.

[0114] Coat the foregoing antiglare layer forming material on the substrate 3 to form a coating film, and cure the foregoing coating film. It is preferable to dry the foregoing coating film before the foregoing curing. The foregoing drying can be, for example, natural drying, air drying by blowing air, heat drying, or a method combining them.

[0115] There is no particular limitation on the curing means for the coating film of the foregoing antiglare layer forming material, and ultraviolet curing is preferred. The irradiation amount of the energy ray source is preferably 50 to 500 mJ / cm in terms of the cumulative exposure amount at an ultraviolet wavelength of 365 nm. 2 If the irradiation amount is 50 mJ / cm 2 or more, the curing is more sufficient, and the hardness of the formed antiglare layer is also more sufficient. In addition, if it is 500 mJ / cm 2 or less, coloring of the formed antiglare layer can be prevented.

[0116] As described above, an antiglare layer 4a can be formed on the surface 3a of the substrate 3. It should be noted that the antiglare layer 4a can be formed by a manufacturing method other than the foregoing method. Regarding the hardness of the antiglare layer 4a of the present embodiment, in terms of pencil hardness, although it is affected by the thickness of the layer, it preferably has a hardness of 2H or more.

[0117] In the present embodiment, the antiglare layer 4a can be a multilayer structure in which two or more layers are laminated.

[0118] In the present embodiment, the above-described AR layer (low refractive index layer) can be disposed on the antiglare layer 4a. For example, when the optical laminate 12 of the present embodiment is installed in a self-luminous display device, one of the main factors reducing the image recognition is the reflection of light at the interface between air and the antiglare layer. The AR layer reduces this surface reflection. It should be noted that the antiglare layer 4a and the antireflection layer may each be a multilayer structure in which two or more layers are laminated.

[0119] In addition, in order to prevent the attachment of contaminants and improve the ease of removing the attached contaminants, it is preferable to laminate a contamination-preventing layer formed of a fluorine group-containing silane compound, a fluorine group-containing organic compound, or the like on the antiglare layer 4a.

[0120] In the present embodiment, it is preferable to perform a surface treatment on at least one of the substrate 3 and the antiglare layer 4a. If the surface of the substrate 3 is surface-treated, the adhesion to the antiglare layer 4a is further improved. In addition, if the surface of the antiglare layer 4a is surface-treated, the adhesion to the aforementioned AR layer is further improved.

[0121] In order to prevent the substrate 3 from curling, the other surface of the antiglare layer 4a can be solvent-treated. In addition, in order to prevent curling, a transparent resin layer can be formed on the other surface of the antiglare layer 4a.

[0122] <Adhesive layer>

[0123] In the present embodiment, the first adhesive layer 1 and the second adhesive layer 2 are adhesive layers formed of an adhesive composition selected from a photocurable adhesive composition and a solvent-based adhesive composition.

[0124] In the present embodiment, the first adhesive layer 1 and the second adhesive layer 2 can both be adhesive layers formed of a photocurable adhesive composition, both be adhesive layers formed of a solvent-based adhesive composition, or one can be an adhesive layer formed of a photocurable adhesive composition and the other can be an adhesive layer formed of a solvent-based adhesive composition.

[0125] In the present embodiment, in terms of excellent height difference absorbency and excellent processability, the first adhesive layer 1 is preferably an adhesive layer formed of a solvent-based adhesive composition. On the other hand, the second adhesive layer 2 can be an adhesive layer formed of a photocurable adhesive composition or an adhesive layer formed of a solvent-based adhesive composition.

[0126] The adhesive composition for forming the first adhesive layer 1 preferably contains a colorant. If the adhesive composition for forming the first adhesive layer 1 contains a colorant, it is preferable in terms of reducing the visible light transmittance of the first adhesive layer 1 and forming a solution where the aforementioned T1 and T2 satisfy T1 < T2. By encapsulating between the metal wiring layer 6 and the LED chip of the self-luminous display device (Mini / Micro LED display device) of the present embodiment with the first adhesive layer 1 having reduced visible light transmittance and imparted light-shielding properties, reflection caused by metal wiring and the like can be prevented, color mixing between LED chips can be prevented, and the contrast of the image can be improved.

[0127] The adhesive composition for forming the second adhesive layer 2 may contain a colorant, but from the perspective of forming a solution where the aforementioned T1 and T2 satisfy T1 < T2, it is preferably colorant-free.

[0128] <Photo-curable adhesive composition>

[0129] The aforementioned photo-curable adhesive composition contains a polymer, a photo-polymerizable compound, and a photo-polymerization initiator. That is, the photo-curable adhesive composition for forming the first adhesive layer 1 and the second adhesive layer 2 of the present embodiment contains a polymer, a photo-polymerizable compound, and a photo-polymerization initiator.

[0130] The adhesive layer formed using the photo-curable adhesive composition is roughly divided into: an adhesive layer of the type that undergoes photo-curing (the first method); and an adhesive layer of the type that does not undergo photo-curing and undergoes photo-curing after being bonded to the display panel described later (the second method). The first adhesive layer 1 and the second adhesive layer 2 can both be adhesive layers of the first method, both be adhesive layers of the second method, or one be an adhesive layer of the first method and the other be an adhesive layer of the second method.

[0131] [First method]

[0132] The adhesive layer of the first method can be formed by coating a photo-curable adhesive composition containing a polymer, a photo-polymerizable compound, and a photo-polymerization initiator on a release film and performing photo-curing.

[0133] <Photo-curable adhesive composition>

[0134] (Polymer)

[0135] Examples of the polymer contained in the above-described photocurable adhesive composition include: acrylic polymers, silicone polymers, polyesters, polyurethanes, polyamides, polyvinyl ethers, vinyl acetate / vinyl chloride copolymers, modified polyolefins, epoxies, fluorides, natural rubbers, synthetic rubbers, and other rubbers, etc. polymers. In particular, from the perspective of exhibiting appropriate adhesive properties such as wettability, aggregability, and adhesiveness, and also excellent weather resistance, heat resistance, etc., acrylic polymers can be suitably used.

[0136] The above acrylic polymer contains an alkyl (meth)acrylate as a main constituent monomer component. It should be noted that in this specification, "(meth)acrylic acid" means acrylic acid and / or methacrylic acid. The amount of the alkyl (meth)acrylate relative to the total amount of the monomer components constituting the acrylic polymer is preferably 50% by weight or more, more preferably 55% by weight or more, and further preferably 60% by weight or more.

[0137] As the alkyl (meth)acrylate, an alkyl (meth)acrylate having 1 to 20 carbon atoms in the alkyl group can be suitably used. The alkyl group of the alkyl (meth)acrylate may have a branch or a cyclic alkyl group.

[0138] Specific examples of the alkyl (meth)acrylate having a linear alkyl group include: methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, isobutyl (meth)acrylate, sec-butyl (meth)acrylate, tert-butyl (meth)acrylate, pentyl (meth)acrylate, isopentyl (meth)acrylate, neopentyl (meth)acrylate, hexyl (meth)acrylate, heptyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octyl (meth)acrylate, isooctyl (meth)acrylate, nonyl (meth)acrylate, isononyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, undecyl (meth)acrylate, dodecyl (meth)acrylate, isotridecyl (meth)acrylate, tetradecyl (meth)acrylate, isotetradecyl (meth)acrylate, pentadecyl (meth)acrylate, cetyl (meth)acrylate, heptadecyl (meth)acrylate, octadecyl (meth)acrylate, isooctadecyl (meth)acrylate, nonadecyl (meth)acrylate, etc. Preferred alkyl (meth)acrylates having a linear alkyl group for the first mode are butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, octadecyl (meth)acrylate, and dodecyl (meth)acrylate. The amount of the alkyl (meth)acrylate having a linear alkyl group relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 40 to 90% by weight, and can be 45 to 80% by weight or 50 to 70% by weight.

[0139] Specific examples of the (meth)acrylic acid alkyl ester having an alicyclic alkyl group include: cycloalkyl (meth)acrylates such as cyclopentyl (meth)acrylate, cyclohexyl (meth)acrylate, cycloheptyl (meth)acrylate, cyclooctyl (meth)acrylate; (meth)acrylates having a bicyclic aliphatic hydrocarbon ring such as isobornyl (meth)acrylate; (meth)acrylates having an aliphatic hydrocarbon ring with three or more rings such as dicyclopentyl (meth)acrylate, dicyclopentyloxyethyl (meth)acrylate, tricyclopentyl (meth)acrylate, 1-adamantyl (meth)acrylate, 2-methyl-2-adamantyl (meth)acrylate, 2-ethyl-2-adamantyl (meth)acrylate. Preferred (meth)acrylic acid alkyl esters having an alicyclic alkyl group for the first mode are cyclohexyl (meth)acrylate and isobornyl (meth)acrylate. The amount of the (meth)acrylic acid alkyl ester having an alicyclic alkyl group relative to the total amount of monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and can be 5 to 40% by weight or 10 to 30% by weight.

[0140] As monomer components constituting the acrylic polymer, it may contain polar group-containing monomers such as hydroxyl group-containing monomers, carboxyl group-containing monomers, and nitrogen-containing monomers. By making the acrylic polymer contain polar group-containing monomers as monomer components, there is a tendency for the cohesive force and adhesive force of the adhesive to increase. Preferred polar group-containing monomers for the first mode are hydroxyl group-containing monomers and nitrogen-containing monomers. The amount of the polar group-containing monomers (the total of the hydroxyl group-containing monomers, carboxyl group-containing monomers, and nitrogen-containing monomers) relative to the total amount of monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and can be 5 to 40% by weight or 10 to 30% by weight.

[0141] Examples of the hydroxyl group-containing monomers include: (meth)acrylic acid esters such as 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4-hydroxymethylcyclohexyl)methyl (meth)acrylate. In the case of introducing a crosslinked structure into the polymer using an isocyanate crosslinking agent, the hydroxyl group can form a reaction site (crosslinking point) with the isocyanate group. Preferred hydroxyl group-containing monomers for the first mode are 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate. The amount of the hydroxyl group-containing monomers relative to the total amount of monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and can be 5 to 40% by weight or 10 to 30% by weight.

[0142] Examples of the carboxyl group-containing monomer include acrylic monomers such as (meth)acrylic acid, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate; and itaconic acid, maleic acid, fumaric acid, crotonic acid, etc. When introducing a crosslinked structure into the polymer using an epoxy-based crosslinking agent, the carboxyl group can form a reaction site (crosslinking point) with the epoxy group. A preferred carboxyl group-containing monomer for the first mode is (meth)acrylic acid. The amount of the carboxyl group-containing monomer relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and can be 5 to 40% by weight or 10 to 30% by weight.

[0143] Examples of the nitrogen-containing monomer include vinyl monomers such as N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, (meth)acryloylmorpholine, N-vinylcarboxylic acid amides, N-vinylcaprolactam, and acrylamide; and cyano group-containing monomers such as acrylonitrile and methacrylonitrile. A preferred nitrogen-containing monomer for the first mode is N-vinylpyrrolidone. The amount of the nitrogen-containing monomer relative to the total amount of the monomer components constituting the acrylic polymer is, for example, about 3 to 50% by weight, and can be 5 to 40% by weight or 10 to 30% by weight.

[0144] As other monomer components (sometimes referred to as "other monomers") of the acrylic polymer, it may include: acid anhydride group-containing monomers, caprolactone adducts of (meth)acrylic acid, sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, vinyl monomers such as vinyl acetate, vinyl propionate, styrene, and α-methylstyrene; epoxy group-containing monomers such as glycidyl (meth)acrylate; diol acrylate monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; and acrylate monomers such as tetrahydrofurfuryl (meth)acrylate, fluoro (meth)acrylate, organosilicon (meth)acrylate, and 2-methoxyethyl (meth)acrylate.

[0145] The glass transition temperature (Tg) of the polymer contained in the photocurable adhesive composition is preferably 0 °C or lower. The glass transition temperature of the polymer can be -5 °C or lower, -10 °C or lower, or -15 °C or lower. The glass transition temperature of the polymer is the peak temperature of the loss tangent (tanδ) based on dynamic viscoelasticity measurement. When a crosslinked structure is introduced into the polymer, the glass transition temperature can be calculated based on the composition of the polymer according to the theoretical Tg. The theoretical Tg is calculated using the Fox formula described later.

[0146] By polymerizing the above monomer components using various known methods, a polymer can be obtained. There is no particular limitation on the polymerization method, and photopolymerization is preferably used to prepare the polymer. Since photopolymerization can prepare the polymer without using a solvent, it is not necessary to dry and remove the solvent when forming the adhesive layer, and an adhesive layer with a large thickness can be uniformly formed.

[0147] In the production of the adhesive layer in the first mode, it is preferably prepared in the form of a low-polymerization-degree polymer (prepolymer) in which a part of the monomer components remains unreacted. The composition for preparing the prepolymer (prepolymer-forming composition) preferably further contains a photoinitiator in addition to the monomer. The photoinitiator can be appropriately selected according to the type of monomer. For example, a photo radical initiator can be used for the polymerization of an acrylic polymer. Examples of the photoinitiator include: benzoin ether photoinitiators, acetophenone photoinitiators, α-ketol photoinitiators, aromatic sulfonyl chloride photoinitiators, photoactive oxime photoinitiators, benzoin photoinitiators, benzil photoinitiators, benzophenone photoinitiators, ketal photoinitiators, thioxanthone photoinitiators, acylphosphine oxide photoinitiators, etc.

[0148] At the time of polymerization, for the purpose of molecular weight regulation, etc., a chain transfer agent, a polymerization inhibitor (polymerization retarder), etc. can be used. Examples of the chain transfer agent include: thiols such as α-thioglycerol, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, mercaptoacetic acid, 2-ethylhexyl mercaptoacetate, 2,3-dimercapto-1-propanol, etc., and α-methylstyrene dimer, etc.

[0149] There is no particular limitation on the polymerization rate of the prepolymer. From the perspective of forming a viscosity suitable for coating on a substrate, it is preferably 3 to 50% by weight, more preferably 5 to 40% by weight. The polymerization rate of the prepolymer can be adjusted to a desired range by adjusting the type and amount of the photoinitiator, the irradiation intensity / irradiation time of active light rays such as UV light, etc. The polymerization rate of the prepolymer is the non-volatile component when heated at 130 °C for 3 hours and is calculated using the following formula. The polymerization rate (non-volatile component) of the adhesive layer is also measured using the same method.

[0150] Polymerization rate (%) = weight after heating / weight before heating × 100

[0151] As described above, the photocurable adhesive composition for forming the adhesive layer contains a polymer, a photopolymerizable compound, and a photoinitiator. For example, a photocurable adhesive composition can be obtained by adding a photopolymerizable compound and a photoinitiator to a prepolymer. Instead of using a prepolymer, a low molecular weight polymer (oligomer) can also be used, and a photopolymerizable compound, a photoinitiator, and a colorant are mixed into the low molecular weight polymer to prepare a photocurable adhesive composition.

[0152] (Photopolymerizable compound)

[0153] The photopolymerizable compound contained in the aforementioned photocurable adhesive composition has one or more photopolymerizable functional groups in one molecule. The photopolymerizable functional group can be any of radical polymerizable, cationic polymerizable, and anionic polymerizable types. From the perspective of excellent reactivity, a radical polymerizable functional group having an unsaturated double bond (olefinic unsaturated group) is preferred.

[0154] The prepolymer contains monomers that have not reacted with the polymer, and the unreacted monomers retain photopolymerizability. Therefore, in the preparation of the photocurable adhesive composition, it is not necessarily required to add a photopolymerizable compound. When a photopolymerizable compound is added to the prepolymer, the added photopolymerizable compound can be the same as or different from the monomer used to prepare the prepolymer.

[0155] In the case where the polymer is an acrylic polymer, from the viewpoint of high compatibility with the polymer, the compound added as the photopolymerizable compound is preferably a monomer or oligomer having a (meth)acryloyl group as the photopolymerizable functional group. The photopolymerizable compound may be a polyfunctional compound having two or more photopolymerizable functional groups in one molecule. Examples of the polyfunctional photopolymerizable compound include polyfunctional (meth)acrylates. Examples of the polyfunctional (meth)acrylate include: polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate, polytetramethylene glycol di(meth)acrylate, bisphenol A ethylene oxide modified di(meth)acrylate, bisphenol A propylene oxide modified di(meth)acrylate, alkanediol di(meth)acrylate, tricyclodecane dimethanol di(meth)acrylate, pentaerythritol di(meth)acrylate, neopentyl glycol di(meth)acrylate, glycerol di(meth)acrylate, urethane di(meth)acrylate and other difunctional (meth)acrylates; pentaerythritol tri(meth)acrylate, trimethylolpropane tri(meth)acrylate and ethoxylated isocyanuric acid tri(meth)acrylate and other trifunctional (meth)acrylates; bis(trimethylolpropane) tetra(meth)acrylate, ethoxylated pentaerythritol tetra(meth)acrylate, pentaerythritol tetra(meth)acrylate and other tetrafunctional (meth)acrylates; dipentaerythritol penta(meth)acrylate and the like and dipentaerythritol hexa(meth)acrylate and other pentafunctional or higher (meth)acrylates.

[0156] When a polyfunctional compound is used as the photopolymerizable compound, regarding the amount of the polyfunctional compound, relative to 100 parts by weight of the polymer (including prepolymer), it is preferably 10 parts by weight or less, more preferably 0.001 to 1 part by weight, and still more preferably 0.005 to 0.5 part by weight. When the amount of the polyfunctional monomer is too large, the viscosity of the adhesive layer after photocuring may sometimes be low and the adhesive strength may be poor. The amount of the polyfunctional compound is 10 parts by weight or less, and may be 5 parts by weight or less, 3 parts by weight or less, or 1 part by weight or less. The amount of the polyfunctional monomer may be 0, and may be 0.001 part by weight or more, 0.01 part by weight or more, or 0.1 part by weight or more.

[0157] When using a monomer that forms a prepolymer as a photopolymerizable compound, a hydroxyl group-containing monomer is preferred, and 2-hydroxyethyl (meth)acrylate and 4-hydroxybutyl (meth)acrylate are more preferred. When using a hydroxyl group-containing monomer as a photopolymerizable compound, regarding the amount of the hydroxyl group-containing monomer, relative to 100 parts by weight of the polymer (including the prepolymer), it is preferably 40 parts by weight or less, more preferably 1 to 30 parts by weight, and further preferably 5 to 20 parts by weight. When the amount of the hydroxyl group-containing monomer is 40 parts by weight or less, it can be 30 parts by weight or less, 20 parts by weight or less. The amount of the hydroxyl group-containing monomer can be 0, and can be 1 part by weight or more, 5 parts by weight or more, or 10 parts by weight or more.

[0158] (Photoinitiator)

[0159] The photocurable adhesive composition contains a photoinitiator. The photoinitiator generates free radicals, acids, bases, etc. by irradiating active light such as ultraviolet rays, and can be appropriately selected according to the type of the photopolymerizable compound, etc. When the photopolymerizable compound is a compound having a (meth)acryloyl group (for example, monofunctional or polyfunctional (meth)acrylate), a photo radical polymerization initiator is preferably used as the photoinitiator. The photoinitiator can be used alone or in combination of two or more.

[0160] When the photoinitiator used in the preparation (polymerization) of the aforementioned polymer (including the prepolymer) remains without inactivation, the addition of the photoinitiator can be omitted. When adding a photoinitiator to the polymer, the added photoinitiator can be the same as or different from the photoinitiator used for preparing the polymer.

[0161] The photoinitiator contained in the photocurable adhesive composition preferably has a maximum absorption in a wavelength region where the light absorption generated by the colorant described below is small. Specifically, the photoinitiator preferably has a maximum absorption in the region of 330 to 400 nm. By making the photoinitiator have a maximum absorption in a region where the light absorption generated by the colorant is small, the curing inhibition caused by the colorant can be suppressed, and thus the polymerization rate can be sufficiently increased by photocuring. Examples of the photo radical polymerization initiator having a maximum absorption in the region of 330 to 400 nm include hydroxyketones, benzoyl dimethyl ketals, aminoketones, acylphosphine oxides, benzophenones, and triazine derivatives containing trichloromethyl.

[0162] Regarding the content of the photoinitiator in the photocurable adhesive composition, relative to 100 parts by weight of the total amount of monomers (monomers used for preparing the polymer and photopolymerizable compounds added to the polymer), it is about 0.01 to 10 parts by weight, preferably about 0.05 to 5 parts by weight.

[0163] (Colorant)

[0164] The photocurable adhesive composition for the first mode may contain a colorant. In particular, the photocurable adhesive composition forming the first adhesive layer 1 preferably further contains a colorant. If the photocurable adhesive composition forming the first adhesive layer 1 contains a colorant, it is preferable in the following aspects: the light transmittance of the first adhesive layer 1 to visible light is reduced, and a scheme in which the aforementioned T1 and the aforementioned T2 satisfy T1 < T2 is formed. By encapsulating between the metal wiring layer 6 and the LED chip of the self-luminous display device (Mini / Micro LED display device) of the present embodiment with the first adhesive layer 1 having reduced light transmittance to visible light and imparted with light-shielding properties, reflection caused by the metal wiring or the like can be prevented, color mixing between the LED chips can be prevented, and the contrast of the image can be improved.

[0165] As long as the aforementioned colorant can be dissolved or dispersed in the photocurable adhesive composition, it can be a dye or a pigment. From the perspective that a low haze can be achieved with a small amount of addition and it is easy to be uniformly distributed without sedimentation like a pigment, a dye is preferred. In addition, from the perspective of obtaining high color rendering with a small amount of addition, a pigment is also preferred. When a pigment is used as the colorant, a pigment with low conductivity or no conductivity is preferred. In addition, when a dye is used, it is preferably used in combination with an antioxidant or the like described later.

[0166] As the aforementioned colorant, there is no particular limitation, and a colorant that absorbs visible light and has ultraviolet transmittance is preferred. That is, the colorant preferably has an average transmittance at wavelengths of 330 to 400 nm greater than the average transmittance at wavelengths of 400 to 700 nm. In addition, the colorant preferably has a maximum transmittance at wavelengths of 330 to 400 nm greater than the maximum transmittance at wavelengths of 400 to 700 nm. Regarding the transmittance of the colorant, a solution or dispersion obtained by diluting with an appropriate solvent such as tetrahydrofuran (THF) or a dispersion medium (an organic solvent with little absorption in the wavelength range of 330 to 700 nm) in such a manner that the transmittance at a wavelength of 400 nm is about 50 to 60% is used for measurement.

[0167] As a black pigment with ultraviolet transmittance whose absorption of ultraviolet rays is less than that of visible light, examples include "9050BLACK", "UVBK-0001", etc. manufactured by TOKUSHIKI CO., Ltd. As a black dye with ultraviolet transmittance, examples include "SOC-L-0123" manufactured by ORIENT CHEMICAL INDUSTRIES CO., LTD.

[0168] Carbon black and titanium black, which are generally used as black colorants, absorb more ultraviolet light than visible light (the ultraviolet transmittance is less than the visible light transmittance). Therefore, if a colorant such as carbon black is added to a photocurable adhesive composition that is sensitive to ultraviolet light, most of the ultraviolet light irradiated for photocuring will be absorbed by the colorant, and the amount of light absorbed by the photoinitiator is small, resulting in time-consuming photocuring (an increase in the cumulative irradiated light amount). In addition, when the thickness of the adhesive layer is large, since there is less ultraviolet light reaching the surface on the opposite side of the light irradiation surface, there is a tendency that photocuring is still insufficient even after long-term light irradiation. In contrast, by using a colorant with a higher ultraviolet transmittance than visible light, the curing inhibition caused by the colorant can be suppressed.

[0169] Regarding the content of the colorant in the photocurable adhesive composition for forming the first adhesive layer, for example, it is about 0.01 to 20 parts by weight relative to 100 parts by weight of the total amount of monomers, and can be appropriately set according to the type of the colorant, the hue of the adhesive layer, the light transmittance, etc. The colorant can be added to the composition in the form of a solution or dispersion dissolved or dispersed in an appropriate solvent.

[0170] The photocurable adhesive composition for forming the second adhesive layer preferably does not contain a colorant. By making the photocurable adhesive composition for forming the second adhesive layer free of a colorant, the light transmittance to visible light is increased, and the luminous efficiency of the self-luminous display device (Mini / Micro LED display device) is improved. When the photocurable adhesive composition for forming the second adhesive layer contains a colorant, its content is, for example, about 0.1 part by weight or less relative to 100 parts by weight of the total amount of monomers. Even when the photocurable adhesive composition for forming the second adhesive layer does not contain a colorant, there may be a case where the colorant blended in the first adhesive layer migrates to the second adhesive layer.

[0171] (Silane coupling agent)

[0172] In the photocurable adhesive composition, a silane coupling agent can be included within a range that does not impair the effects of the present invention. If the photocurable adhesive composition contains a silane coupling agent, it is preferable because the bonding reliability to glass (especially the bonding reliability to glass in a high-temperature and high-humidity environment) is improved.

[0173] As the aforementioned silane coupling agent, there is no particular limitation, and preferably, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-aminopropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, etc. can be cited. Among them, γ-glycidoxypropyltrimethoxysilane is preferred. In addition, as commercially available products, for example, "KBM-403" (manufactured by Shin-Etsu Chemical Co., Ltd.) can be cited. It should be noted that the silane coupling agent can be used alone or in combination of two or more kinds.

[0174] There is no particular limitation on the content of the silane coupling agent in the photocurable adhesive composition. Relative to 100 parts by weight of the polymer, it is preferably 0.01 to 1 part by weight, more preferably 0.03 to 0.5 part by weight.

[0175] (Other components)

[0176] In the first mode, the photocurable adhesive composition may contain components other than the polymer, the photopolymerizable compound, the photoinitiator, and the colorant. For example, for the purpose of adjusting the photocuring rate, etc., a chain transfer agent may be contained. In addition, for the purpose of adjusting the viscosity of the aforementioned photocurable adhesive composition, the adhesive force of the adhesive layer, etc., an oligomer and a tackifier may be contained. As the oligomer, for example, an oligomer having a weight average molecular weight of about 1000 to 30000 can be used. As the oligomer, from the perspective of excellent compatibility with the acrylic polymer, an acrylic oligomer is preferred. The aforementioned photocurable adhesive composition may contain additives such as a plasticizer, a softening agent, an anti-degradant, a filler, an antioxidant, a surfactant, and an antistatic agent.

[0177] [Second mode]

[0178] The adhesive layer of the second mode is a type of adhesive layer that is not photocured, and is an adhesive layer obtained by forming the photocurable adhesive composition into a sheet. Since the adhesive layer of the second mode contains the photopolymerizable compound in an unreacted state, the adhesive layer has photocurability.

[0179] The photocurable adhesive composition for forming the adhesive layer of the second mode contains a polymer, a photopolymerizable compound, and a photoinitiator.

[0180] (Polymer)

[0181] As the polymer contained in the adhesive composition, the same as in the first mode, various polymers can be applied, and an acrylic polymer can be suitably used. The monomer components constituting the acrylic polymer are the same as in the first mode.

[0182] In order to introduce a crosslinked structure using the crosslinking agent described later, it is preferable to include a hydroxyl group-containing monomer and / or a carboxyl group-containing monomer in the monomer components constituting the polymer. For example, in the case of using an isocyanate-based crosslinking agent, it is preferable to contain a hydroxyl group-containing monomer as a monomer component. In the case of using an epoxy-based crosslinking agent, it is preferable to contain a carboxyl group-containing monomer as a monomer.

[0183] In the second method, since photocuring is not performed on the substrate, in order to form a solid (certain shape) adhesive layer, as the polymer contained in the photocurable adhesive composition, a polymer with a relatively large molecular weight can be used. The weight average molecular weight of the polymer is, for example, about 100,000 to 2,000,000.

[0184] Since the high molecular weight polymer is solid, the adhesive composition is preferably a solution in which the polymer is dissolved in an organic solvent. For example, a polymer solution can be obtained by solution polymerization of monomer components. A polymer solution can be prepared by dissolving the solid polymer in an organic solvent.

[0185] As the solvent for solution polymerization, ethyl acetate, toluene, etc. are generally used. The solution concentration is usually about 20 to 80% by weight. As the polymerization initiator, thermal polymerization initiators such as azo-based initiators, peroxide-based initiators, and redox initiators obtained by combining peroxides and reducing agents (for example, the combination of persulfate and sodium bisulfite, the combination of peroxide and sodium ascorbate) are preferably used. There is no particular limitation on the amount of the polymerization initiator. For example, relative to 100 parts by weight of the total monomer components forming the polymer, it is preferably about 0.005 to 5 parts by weight, and more preferably about 0.02 to 3 parts by weight.

[0186] (Photopolymerizable compound)

[0187] In the second method, the photopolymerizable compound contained in the adhesive composition is the same as that described for the first method above, and a compound having one or more photopolymerizable functional groups can be used.

[0188] (Photopolymerization initiator)

[0189] In the second method, the photopolymerization initiator contained in the adhesive composition is the same as that described for the first method above, and a photopolymerization initiator having a maximum absorption in the wavelength region of 330 to 400 nm is preferably used. The amount of the photopolymerization initiator is about 0.01 to 10 parts by weight, preferably about 0.05 to 5 parts by weight, relative to 100 parts by weight of the polymer.

[0190] (Colorant)

[0191] The adhesive composition used in the second mode may contain a colorant. In particular, the photocurable adhesive composition forming the first adhesive layer 1 preferably further contains a colorant. If the photocurable adhesive composition forming the first adhesive layer 1 contains a colorant, it is preferable in the following aspects: the light transmittance of the first adhesive layer 1 to visible light is reduced, and a scheme where the aforementioned T1 and the aforementioned T2 satisfy T1 < T2 is formed. By encapsulating the metal wiring layer 6 and the LED chip of the self-luminous display device (Mini / Micro LED display device) of the present embodiment with the first adhesive layer 1 having reduced light transmittance to visible light and imparted light-shielding properties, reflection caused by the metal wiring and the like can be prevented, color mixing between LED chips can be prevented, and the contrast of the image can be improved.

[0192] The colorant contained in the adhesive composition used in the second mode is the same as that described above for the first mode, and preferably has an average transmittance at wavelengths of 330 to 400 nm greater than the average transmittance at wavelengths of 400 to 700 nm. In addition, the colorant preferably has a maximum transmittance at wavelengths of 330 to 400 nm greater than the maximum transmittance at wavelengths of 400 to 700 nm.

[0193] (Crosslinking agent)

[0194] The adhesive composition of the second mode preferably contains a crosslinking agent capable of crosslinking with the above polymer. Specific examples of the crosslinking agent for introducing a crosslinked structure into the polymer include: isocyanate crosslinking agents, epoxy crosslinking agents, oxazoline crosslinking agents, aziridine crosslinking agents, carbodiimide crosslinking agents, metal chelate crosslinking agents, etc. Among them, isocyanate crosslinking agents and epoxy crosslinking agents are preferred from the perspective of high reactivity with the hydroxyl and carboxyl groups of the polymer and easy introduction of a crosslinked structure. These crosslinking agents react with functional groups such as hydroxyl and carboxyl groups introduced into the polymer to form a crosslinked structure.

[0195] As the isocyanate crosslinking agent, polyisocyanates having two or more isocyanate groups in one molecule can be used. Examples of the isocyanate crosslinking agent include lower aliphatic polyisocyanates such as butylene diisocyanate and hexamethylene diisocyanate; alicyclic isocyanates such as cyclopentylene diisocyanate, cyclohexylene diisocyanate, and isophorone diisocyanate; aromatic isocyanates such as 2,4-toluene diisocyanate, 4,4'-diphenylmethane diisocyanate, and xylylene diisocyanate; trimethylolpropane / toluene diisocyanate trimer adduct (e.g., "CORONATE L" manufactured by Tosoh Corporation), trimethylolpropane / hexamethylene diisocyanate trimer adduct (e.g., "CORONATE HL" manufactured by Tosoh Corporation), trimethylolpropane adduct of xylylene diisocyanate (e.g., "TAKENATE D110N" manufactured by Mitsui Chemicals, Inc.), isocyanurate of hexamethylene diisocyanate (e.g., "CORONATE HX" manufactured by Tosoh Corporation), and other isocyanate adducts.

[0196] As the epoxy crosslinking agent, polyfunctional epoxides having two or more epoxy groups in one molecule can be used. The epoxy group of the epoxy crosslinking agent may be a glycidyl group. Examples of the epoxy crosslinking agent include N,N,N',N'-tetraglycidyl-m-xylenediamine, diglycidylaniline, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, 1,6-hexanediol diglycidyl ether, neopentyl glycol diglycidyl ether, ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, sorbitol polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, polyglycerol polyglycidyl ether, sorbitan polyglycidyl ether, trimethylolpropane polyglycidyl ether, adipic acid diglycidyl ester, phthalic acid diglycidyl ester, triglycidyl-tris(2-hydroxyethyl)isocyanurate, resorcinol diglycidyl ether, bisphenol-S-diglycidyl ether, etc. As the epoxy crosslinking agent, commercially available products such as "DENACOL" manufactured by Nagase ChemteX Corporation, "TETRAD X" and "TETRAD C" manufactured by Mitsubishi Gas Chemical Company, Inc. can be used.

[0197] The amount of the crosslinking agent is about 0.01 to 5 parts by weight relative to 100 parts by weight of the polymer, and can be 0.05 parts by weight or more, 0.1 parts by weight or more, or 0.2 parts by weight or more, and can be 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight or less.

[0198] (Other components)

[0199] In addition to the above components, the adhesive composition of the second method may further contain oligomers, tackifiers, silane coupling agents, chain transfer agents, plasticizers, softeners, anti-deterioration agents, fillers, antioxidants, surfactants, antistatic agents, etc.

[0200] <Solvent-based adhesive composition>

[0201] In the present embodiment, the first adhesive layer 1 and the second adhesive layer 2 may be adhesive layers (third method) formed of a solvent-based adhesive composition. The aforementioned solvent-based adhesive composition contains at least a polymer and a solvent, and may contain a crosslinking agent. That is, the solvent-based adhesive composition for forming the adhesive layer of the third method contains a polymer and a solvent, and may contain a crosslinking agent as needed.

[0202] [Third method]

[0203] The adhesive layer of the third method can be formed by applying a solvent-based adhesive composition containing a polymer and a solvent, and containing a crosslinking agent as needed, on a release film and drying and removing the solvent.

[0204] The solvent-based adhesive composition for forming the adhesive layer of the third method contains a polymer and a solvent, and contains a crosslinking agent as needed.

[0205] (Polymer)

[0206] As the polymer contained in the solvent-based adhesive composition, various polymers can be applied as in the first method, and acrylic polymers can be suitably used. The monomer components constituting the acrylic polymer are the same as in the first method.

[0207] In the third method, in order to form a solid (certain shape) adhesive layer on the substrate, a polymer having a relatively large molecular weight can be used as the polymer contained in the solvent-based adhesive composition. The weight average molecular weight of the polymer is, for example, about 100,000 to 2,000,000.

[0208] The aforementioned acrylic polymer contained in the solvent-based adhesive composition of the third method may be a (meth)acrylic block copolymer. When the first adhesive layer 1 and / or the second adhesive layer 2 are formed of a solvent-based adhesive composition containing a (meth)acrylic block copolymer, since the height difference absorbability is excellent and the processability is also excellent, it is possible to encapsulate the height difference of a plurality of LED chips arranged on the substrate of the display panel without gaps and without leaving bubbles, and the processability is also excellent, so that it is not easy to occur the adverse situation that the adhesive layer oozes out from the end during storage.

[0209] In the present embodiment, the adhesive composition for forming the first adhesive layer 1 is preferably a solvent-based adhesive composition containing a (meth)acrylic block copolymer. According to this solution, the first adhesive layer 1 has excellent height difference absorbability and excellent processability, and can encapsulate the height differences of a plurality of LED chips, metal wirings, etc. arranged on the substrate of the display panel without leaving gaps and without residual bubbles. Therefore, it is possible to prevent color mixing between LED chips, improve the contrast of the image, and efficiently prevent reflection caused by metal wirings, etc.

[0210] In the present embodiment, preferably, the (meth)acrylic block copolymer has: a high Tg segment having a glass transition temperature of 0°C or higher and 100°C or lower, and a low Tg segment having a glass transition temperature of -100°C or higher and lower than 0°C, and has peaks of tanδ in the region of 0°C or higher and the region lower than 0°C, respectively.

[0211] In this specification, the "high Tg segment having a glass transition temperature of 0°C or higher and 100°C or lower" is sometimes simply referred to as the "high Tg segment", the "low Tg segment having a glass transition temperature of -100°C or higher and lower than 0°C" is simply referred to as the "low Tg segment", the peak of tanδ in the region of 0°C or higher is simply referred to as the "high temperature region tanδ peak", the peak of tanδ in the region lower than 0°C is simply referred to as the "low temperature region tanδ peak", the (meth)acrylic block copolymer having the aforementioned high Tg segment, low Tg segment, high temperature region tanδ peak, and low temperature region tanδ peak is called "(meth)acrylic block copolymer A", and the solvent-based adhesive composition containing the aforementioned (meth)acrylic block copolymer A is called "solvent-based adhesive composition A".

[0212] The "segment" in the high Tg segment and the low Tg segment refers to a partial structure of each block unit constituting the (meth)acrylic block copolymer A.

[0213] The structure of the aforementioned (meth)acrylic block copolymer A may be a linear block copolymer, a branched (star) block copolymer, or a mixture thereof. The structure of such a block copolymer can be appropriately selected according to the required physical properties of the block copolymer. From the perspective of cost and ease of manufacture, a linear block copolymer is preferred. In addition, the linear block copolymer can be any structure (arrangement). From the perspective of the physical properties of the linear block copolymer or the physical properties of the solvent-based adhesive composition A, it is preferably selected from (A-B) n type, (A-B) n-type (n is an integer of 1 or more, for example, an integer of 1 to 3). Among these structures, A and B represent segments composed of different monomers. In this specification, the segment represented by A constituting the aforementioned linear block copolymer may sometimes be referred to as the "A segment", and the segment represented by B may be referred to as the "B segment".

[0214] Among these, from the viewpoints of ease of production, physical properties of the solvent-based adhesive composition A, etc., an AB-type diblock copolymer represented by A-B or an ABA-type triblock copolymer represented by A-B-A is preferred, and an ABA-type triblock copolymer is more preferred. It is considered that in the ABA-type triblock copolymer, through the pseudo-crosslinking between the A segments at both ends, the crosslinked structure between the block copolymers becomes a more highly crosslinked structure, the cohesion of the block copolymer is improved, and higher adhesiveness (adhesion) can be exhibited. It should be noted that in the ABA-type triblock copolymer, the two A segments located at both ends may be the same as or different from each other.

[0215] In the case where the (meth)acrylic block copolymer A is an ABA-type triblock copolymer, among the two A segments and one B segment (a total of three), at least one may be a high-Tg segment and at least another may be a low-Tg segment. From the viewpoints of ease of production, physical properties of the solvent-based adhesive composition A, etc., an ABA-type triblock copolymer in which the A segment is the aforementioned high-Tg segment and the B segment is the aforementioned low-Tg segment is preferred. In this case, an ABA-type triblock copolymer in which at least one of the two A segments is a high-Tg segment and the B segment is a low-Tg segment is preferred, and an ABA-type triblock copolymer in which both of the two A segments are high-Tg segments and the B segment is a low-Tg segment is more preferred.

[0216] As described above, the glass transition temperature (Tg) of the high-Tg segment constituting the (meth)acrylic block copolymer A is 0°C or higher and 100°C or lower. By setting the Tg of the high-Tg segment within this range, there is a tendency that it is easy to control the storage modulus of the solvent-based adhesive composition A at room temperature (25°C) to be relatively high, it is hard and has excellent processability, and in the region exceeding 50°C, the storage modulus is significantly reduced, resulting in a highly fluid adhesive composition. From the viewpoint of improving the processability of the solvent-based adhesive composition A at room temperature (25°C), the Tg of the high-Tg segment is preferably 4°C or higher, more preferably 6°C or higher, further preferably 8°C or higher, still further preferably 10°C or higher, and particularly preferably 12°C or higher. On the other hand, from the viewpoint that the storage modulus (G') of the solvent-based adhesive composition A is significantly reduced in the region exceeding 50°C and it is easy to form a highly fluid state, the Tg of the high-Tg segment is preferably 90°C or lower, more preferably 85°C or lower, further preferably 60°C or lower, still further preferably 50°C or lower, and particularly preferably 35°C or lower.

[0217] As described above, the Tg of the low-Tg segment constituting the (meth)acrylic block copolymer A is above -100°C and below 0°C. By setting the glass Tg of the low-Tg segment within this range, there is a tendency that only this low-Tg segment becomes fluid at room temperature (25°C), and while ensuring processability, an appropriate adhesive force can be imparted to the solvent-based adhesive composition A. From the perspective that the storage modulus of the solvent-based adhesive composition A is not easily reduced at room temperature (25°C) and processability can be improved, the Tg of the low-Tg segment is preferably -95°C or higher, more preferably -90°C or higher, further preferably -80°C or higher. On the other hand, from the perspective of being able to improve the appropriate adhesive force and processability of the solvent-based adhesive composition A at room temperature (25°C), the Tg of the low-Tg segment is preferably -5°C or lower, more preferably -10°C or lower, further preferably -20°C or lower, still further preferably -30°C or lower, and particularly preferably -40°C or lower.

[0218] There is no particular limitation on the difference in Tg between the high-Tg segment and the low-Tg segment constituting the (meth)acrylic block copolymer A (Tg of the high-Tg segment - Tg of the low-Tg segment). From the perspective of easily controlling the storage modulus of the solvent-based adhesive composition A to be relatively high, hard, and having excellent processability at room temperature (25°C) and the storage modulus significantly decreasing in the region above 50°C to become a highly fluid adhesive composition, it is preferably 30°C or higher, more preferably 35°C or higher, more preferably 40°C or higher, more preferably 45°C or higher, further preferably 50°C or higher, particularly preferably 55°C or higher, preferably 120°C or lower, more preferably 115°C or lower, more preferably 110°C or lower, more preferably 105°C or lower, further preferably 100°C or lower, and particularly preferably 95°C or lower.

[0219] The glass transition temperatures (Tg) of the high-Tg segment and the low-Tg segment constituting the (meth)acrylic block copolymer A are the calculated glass transition temperatures calculated according to the following Fox formula. Since this calculated glass transition temperature is based on the types and amounts of the respective monomer components of the high-Tg segment or the low-Tg segment constituting the (meth)acrylic block copolymer A, it can be adjusted by selecting the types and amounts of the monomer components of each segment, etc.

[0220] The calculated glass transition temperature (calculated Tg) can be calculated according to the following Fox formula [1].

[0221] 1 / calculated Tg = W1 / Tg(1) + W2 / Tg(2) + … + Wn / Tg(n) [1]

[0222] Here, W1, W2, … Wn represent the respective weight fractions (wt%) of monomer components (1), monomer components (2), … monomer components (n) that constitute the copolymer relative to all monomer components, and Tg(1), Tg(2), … Tg(n) represent the glass transition temperatures (unit: absolute temperature: K) of the homopolymers of monomer components (1), monomer components (2), … monomer components (n).

[0223] It should be noted that the glass transition temperatures of homopolymers are well-known in various literatures, product catalogs, etc. For example, they are described in J. Brandup, E. H. Immergut, E. A. Grulke: Polymer Handbook: JOHN WILEY & SONS, INC. For monomers without numerical records in various literatures, values measured by conventional thermal analysis, such as differential thermal analysis, dynamic viscoelasticity measurement method, etc., can be used.

[0224] As described above, the temperature range in which the tanδ peak in the high-temperature region of the (meth)acrylic block copolymer A appears is 0 °C or higher (for example, 0 °C or higher and 100 °C or lower). By setting the tanδ peak in the high-temperature region within this temperature range, there is a tendency that it is easy to control the storage modulus of the solvent-based adhesive composition A at room temperature (25 °C) to be relatively high, hard and excellent in processability, and the storage modulus significantly decreases in the region above 50 °C, becoming a highly fluid adhesive composition. From the perspective of improving the processability of the solvent-based adhesive composition A at room temperature (25 °C), the temperature at which the tanδ peak in the high-temperature region appears is preferably 3 °C or higher, more preferably 6 °C or higher, further preferably 9 °C or higher, still further preferably 12 °C or higher, and particularly preferably 15 °C or higher. On the other hand, from the perspective that the storage modulus (G’) of the solvent-based adhesive composition A significantly decreases in the region above 50 °C and it is easy to form high fluidity, the temperature at which the tanδ peak in the high-temperature region appears is preferably 90 °C or lower, more preferably 80 °C or lower, further preferably 70 °C or lower, still further preferably 65 °C or lower, and particularly preferably 60 °C or lower.

[0225] (The temperature range in which the tanδ peak in the low-temperature region of the (meth)acrylic block copolymer A appears is lower than 0°C as described above (for example, not less than -100°C and lower than 0°C). By making the tanδ peak in the low-temperature region within this temperature range, there is a tendency that only the low-Tg segment is fluidized at room temperature (25°C), and while ensuring processability, an appropriate adhesive force can be imparted to the solvent-based adhesive composition A. From the perspective that the storage modulus of the solvent-based adhesive composition A is not easily reduced at room temperature (25°C) and the processability can be improved, the temperature at which the tanδ peak in the low-temperature region appears is preferably not less than -95°C, more preferably not less than -90°C, further preferably not less than -80°C, still further preferably not less than -70°C. On the other hand, from the perspective of being able to improve the appropriate adhesive force and processability of the solvent-based adhesive composition A at room temperature (25°C), the temperature at which the tanδ peak in the low-temperature region appears is preferably not more than -5°C, more preferably not more than -10°C, further preferably not more than -20°C, still further preferably not more than -30°C, and particularly preferably not more than -40°C.)

[0226] There is no particular limitation on the maximum value of the tanδ peak in the aforementioned high-temperature region, and it is preferably 0.5 to 3.0. By making the maximum value of the tanδ peak in the high-temperature region within this range, the excellent processability and shape stability of the aforementioned (meth)acrylic block copolymer A can be achieved, which is preferable in this regard. From the perspective of being able to achieve excellent processability, the maximum value of the tanδ peak in the high-temperature region is preferably 0.6 or more, more preferably 0.7 or more. In addition, from the perspective of being less likely to produce indentations, the maximum value of the tanδ peak in the high-temperature region is preferably 2.5 or less, more preferably 2.2 or less.)

[0227] There is no particular limitation on the maximum value of the tanδ peak in the aforementioned low-temperature region, and it is preferably 0.1 to 2.0. By making the maximum value of the tanδ peak in the low-temperature region within this range, the excellent processability and shape stability of the aforementioned (meth)acrylic block copolymer A can be achieved, which is preferable in this regard. From the perspective of being able to achieve excellent processability, the maximum value of the tanδ peak in the high-temperature region is preferably 0.2 or more, more preferably 0.3 or more. In addition, from the perspective of being less likely to produce indentations, the maximum value of the tanδ peak in the low-temperature region is preferably 1.5 or less, more preferably 1 or less.)

[0228] It should be noted that the aforementioned tanδ peaks in the high-temperature region and low-temperature region, as well as the temperatures and maximum values at which they appear, are measured by dynamic viscoelasticity measurement.)

[0229] (Meth)acrylic block copolymer A is composed of a plurality of segments (including high Tg segments and low Tg segments) obtained by polymerizing monomer components, and the monomer components include monomers having a (meth)acryloyl group in the molecule (acrylic monomers).

[0230] (Meth)acrylic block copolymer A or each of its segments preferably contains 70% by weight or more, more preferably 80% by weight or more, and particularly preferably 90% by weight or more of acrylic monomers based on the total amount of monomer components (100% by weight).

[0231] As the acrylic monomers constituting (meth)acrylic block copolymer A or each of its segments (including high Tg segments and low Tg segments), monomer components including an alkyl acrylate having a linear or branched alkyl group and / or a methyl acrylate alkyl ester derived from a methyl acrylate alkyl ester having a linear or branched alkyl group are included as the main monomer units in the largest proportion by weight.

[0232] As the alkyl (meth)acrylate having a linear or branched alkyl group used for forming the segments of (meth)acrylic block copolymer A, specific examples of the above-mentioned alkyl (meth)acrylate having a chain-like alkyl group can be cited. As the alkyl (meth)acrylate for the aforementioned segments, one alkyl (meth)acrylate can be used, or two or more alkyl (meth)acrylates can be used. As the alkyl (meth)acrylate for the aforementioned segments, at least one selected from the group consisting of methyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, tert-butyl acrylate, hexyl acrylate, heptyl acrylate, octyl acrylate, and isononyl acrylate is preferably used.

[0233] The segment of the (meth)acrylic block copolymer A may contain monomer units derived from alicyclic monomers. As the alicyclic monomers for forming the aforementioned segment, specific examples of the (meth)acrylic acid alkyl esters having an alicyclic alkyl group as described above can be cited. The aforementioned alicyclic alkyl group may have a substituent. Examples of the substituent include: halogen atoms (such as fluorine atom, chlorine atom, bromine atom, iodine atom), linear or branched alkyl groups having 1 to 6 carbon atoms (such as methyl, ethyl, n-propyl, isopropyl, etc.). There is no particular limitation on the number of the aforementioned substituents, and it can be appropriately selected from 1 to 6. When there are two or more of the substituents, the two or more substituents may be the same or different. As the alicyclic monomer for the aforementioned segment, one alicyclic monomer can be used, or two or more alicyclic monomers can be used. As the alicyclic monomer for the aforementioned segment, a (meth)acrylic cycloalkyl ester having a cycloalkyl group with 4 to 10 carbon atoms optionally having a substituent (such as a linear or branched alkyl group having 1 to 6 carbon atoms) is preferred, and at least one selected from the group consisting of cyclohexyl acrylate and 3,3,5-trimethylcyclohexyl (meth)acrylate is more preferably used.

[0234] The segment of the (meth)acrylic block copolymer A may contain monomer units derived from hydroxyl group-containing monomers. The hydroxyl group-containing monomer is a monomer having at least one hydroxyl group in the monomer unit. When the segment in the (meth)acrylic block copolymer A contains a hydroxyl group-containing monomer unit, adhesiveness and moderate cohesion can be easily obtained in the solvent-based adhesive composition A.

[0235] As the hydroxyl group-containing monomer for forming the aforementioned segment, specific examples of the aforementioned hydroxyl group-containing monomers can be cited. As the hydroxyl group-containing monomer for the aforementioned segment, one hydroxyl group-containing monomer can be used, or two or more hydroxyl group-containing monomers can be used. As the hydroxyl group-containing monomer for the aforementioned segment, a hydroxyl group-containing (meth)acrylate is preferred, and at least one selected from the group consisting of 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 4-hydroxybutyl acrylate, and 4-hydroxybutyl methacrylate is more preferably used.

[0236] The segment of the (meth)acrylic block copolymer A may contain monomer units derived from nitrogen atom-containing monomers. The nitrogen atom-containing monomer is a monomer having at least one nitrogen atom in the monomer unit. When the segment of the (meth)acrylic block copolymer A contains a nitrogen atom-containing monomer unit, hardness and good adhesion reliability can be easily obtained in the solvent-based adhesive composition A.

[0237] As the nitrogen atom-containing monomer for forming the foregoing segment, specific examples of the above nitrogen atom-containing monomer can be cited. As the nitrogen atom-containing monomer for the acrylic polymer, one nitrogen atom-containing monomer can be used, or two or more nitrogen atom-containing monomers can be used. As the nitrogen atom-containing monomer for the foregoing segment, N-vinyl-2-pyrrolidone is preferably used.

[0238] The segment of the (meth)acrylic block copolymer A may contain monomer units derived from a carboxyl group-containing monomer. The carboxyl group-containing monomer is a monomer having at least one carboxyl group in the monomer unit. When the segment of the (meth)acrylic block copolymer A contains a carboxyl group-containing monomer unit, good adhesion reliability can sometimes be obtained in the solvent-based adhesive composition A.

[0239] As the carboxyl group-containing monomer for forming the foregoing segment of the monomer unit, specific examples of the above carboxyl group-containing monomer can be cited. As the carboxyl group-containing monomer for the foregoing segment, one carboxyl group-containing monomer can be used, or two or more carboxyl group-containing monomers can be used. As the carboxyl group-containing monomer for the foregoing segment, acrylic acid is preferably used.

[0240] Furthermore, as the monomer unit for forming the foregoing segment, the above other monomers can be cited. Regarding the content of other monomers in the monomer units constituting the segment of the (meth)acrylic block copolymer A, as long as it is 30% by weight or less relative to the total amount of monomer components (100% by weight), there is no particular limitation, and it can be appropriately selected within the range that does not impair the effects of the present invention.

[0241] As the monomer component of the high-Tg segment constituting the (meth)acrylic block copolymer A, from the viewpoint of easily controlling the Tg of the high-Tg segment within a specified range and being able to impart desired physical properties to the (meth)acrylic block copolymer A, it is preferably contained and selected from (meth)acrylic acid alkyl esters having a linear alkyl group with 1 to 3 carbon atoms (hereinafter sometimes referred to as "(meth)acrylic acid C 1-3 linear alkyl ester"), (meth)acrylic acid alkyl esters having a branched alkyl group with 3 or 4 carbon atoms (hereinafter sometimes referred to as "(meth)acrylic acid C 3-4 branched alkyl ester") and alicyclic monomers. The homopolymers of these monomers have relatively high Tg, so by containing monomers selected from them as the monomer component constituting the high-Tg segment, it is easy to control the Tg of the high-Tg segment within the range specified by the present invention.

[0242] As the aforementioned alicyclic monomer, it is preferably a cycloalkyl (meth)acrylate having a cycloalkyl group with 4 to 10 carbon atoms, optionally having a substituent (e.g., a linear or branched alkyl group with 1 to 6 carbon atoms), more preferably a cycloalkyl acrylate having a cycloalkyl group with 4 to 10 carbon atoms, optionally having a substituent (e.g., a linear or branched alkyl group with 1 to 6 carbon atoms), and particularly preferably cyclohexyl acrylate (Tg of the homopolymer: 15°C), 3,3,5-trimethylcyclohexyl (meth)acrylate (Tg of the homopolymer: 52°C).

[0243] When the alicyclic monomer is contained as a monomer component constituting the high-Tg segment, the content of the alicyclic monomer relative to the total amount of the monomer components (100% by weight) is preferably 10% by weight or more (e.g., 10 to 100% by weight), more preferably 20% by weight or more, more preferably 30% by weight or more, more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 80% by weight or more, further preferably 90% by weight or more, and particularly preferably 95% by weight or more, from the viewpoint of easily controlling the Tg of the high-Tg segment within a specified range and being able to impart desired physical properties to the (meth)acrylic block copolymer A.

[0244] As the aforementioned (meth)acrylic acid C 1-3 linear alkyl ester, acrylic acid C 1-3 linear alkyl ester is preferred, and methyl acrylate (Tg of the homopolymer: 8°C) is particularly preferred.

[0245] As the aforementioned (meth)acrylic acid C 3-4 branched alkyl ester, acrylic acid C 3-4 branched alkyl ester is preferred, and tert-butyl acrylate (Tg of the homopolymer: 35°C) is particularly preferred.

[0246] When the (meth)acrylic acid C 1-3 linear alkyl ester and / or the (meth)acrylic acid C 3-4 branched alkyl ester is contained as a monomer component constituting the high-Tg segment, regarding the (meth)acrylic acid C 1-3 linear alkyl ester and / or the (meth)acrylic acid C 3-4The content of the branched alkyl ester relative to the total amount of the monomer components (100% by weight) is preferably 10% by weight or more (for example, 10 to 100% by weight), more preferably 20% by weight or more, more preferably 30% by weight or more, more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 80% by weight or more, further preferably 90% by weight or more, and particularly preferably 95% by weight or more, from the viewpoint of easily controlling the Tg of the high-Tg segment within a specified range and being able to impart desired physical properties to the (meth)acrylic block copolymer A.

[0247] As the monomer component of the low-Tg segment constituting the (meth)acrylic block copolymer A, from the viewpoint of easily controlling the Tg of the low-Tg segment within a specified range and being able to impart desired physical properties to the (meth)acrylic block copolymer A, it is preferably to contain at least one selected from the group consisting of (meth)acrylic alkyl esters having a linear or branched alkyl group with 4 to 18 carbon atoms (hereinafter sometimes referred to as “(meth)acrylic C 4-18 alkyl esters”) and hydroxyl group-containing monomers. That is, the homopolymer of the (meth)acrylic C 4-18 alkyl ester has a relatively low Tg. Therefore, by containing it as the monomer component constituting the low-Tg segment, it is easy to control the Tg of the low-Tg segment within the range specified in the present invention. On the other hand, the hydroxyl group-containing monomer also has a relatively low Tg. Furthermore, adhesiveness and appropriate cohesive force are easily obtained in the (meth)acrylic block copolymer A. Therefore, as the monomer component of the low-Tg segment constituting the (meth)acrylic block copolymer A, it is further preferred to contain both the (meth)acrylic C 4-18 alkyl ester and the hydroxyl group-containing monomer.

[0248] As the aforementioned (meth)acrylic C 4-18 alkyl ester, acrylic C 4-18 alkyl ester is preferred, and butyl acrylate (Tg of homopolymer: -55°C), 2-ethylhexyl acrylate (Tg of homopolymer: -70°C), n-hexyl acrylate (Tg of homopolymer: -57°C), n-octyl acrylate (Tg of homopolymer: -65°C), and isononyl acrylate (Tg of homopolymer: -58°C) are particularly preferred.

[0249] In the case where the (meth)acrylic C 4-18 alkyl ester is contained as the monomer component of the low-Tg segment, regarding the (meth)acrylic C 4-18The content of the alkyl ester relative to the total amount of monomer components (100% by weight) is preferably 10% by weight or more (for example, 10 to 100% by weight), more preferably 20% by weight or more, more preferably 30% by weight or more, more preferably 30% by weight or more, more preferably 40% by weight or more, more preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 80% by weight or more, further preferably 90% by weight or more, and particularly preferably 95% by weight or more, from the viewpoint of easily controlling the Tg of the low-Tg segment within a specified range and being able to impart desired physical properties to the (meth)acrylic block copolymer A.

[0250] As the aforementioned hydroxyl group-containing monomer, a hydroxyl group-containing (meth)acrylic acid alkyl ester is preferred, and 4-hydroxybutyl acrylate (Tg of the homopolymer: -65°C) and 2-hydroxyethyl acrylate (Tg of the homopolymer: -15°C) are particularly preferred.

[0251] When a hydroxyl group-containing monomer is contained as a monomer component constituting the low-Tg segment, regarding the content of the hydroxyl group-containing monomer relative to the total amount of monomer components (100% by weight), from the viewpoint of easily controlling the Tg of the low-Tg segment within a specified range and being able to impart desired physical properties to the (meth)acrylic block copolymer A, it is preferably 1% by weight or more, more preferably 1.5% by weight or more, more preferably 2% by weight or more, further preferably 2.5% by weight or more, and particularly preferably 3% by weight or more. On the other hand, the content of the hydroxyl group-containing monomer relative to the total amount of monomer components (100% by weight) is preferably 50% by weight or less, more preferably 40% by weight or less, more preferably 30% by weight or less, more preferably 20% by weight or less, further preferably 10% by weight or less, and particularly preferably 5% by weight or less.

[0252] When both a (meth)acrylic acid C 4-18 alkyl ester and a hydroxyl group-containing monomer are contained as monomer components constituting the low-Tg segment of the (meth)acrylic block copolymer A, the ratio of the hydroxyl group-containing monomer to the (meth)acrylic acid C 4-18 alkyl ester (hydroxyl group-containing monomer / (meth)acrylic acid C 4-18 alkyl ester) is not particularly limited. The lower limit value is preferably 1 / 99, more preferably 1.5 / 98.5, more preferably 2 / 98, further preferably 2.5 / 97.5, and particularly preferably 3 / 97. On the other hand, the upper limit value is preferably 50 / 50, more preferably 40 / 60, more preferably 30 / 70, and further preferably 20 / 80.

[0253] (Meth)acrylic block copolymer A can be produced by the living radical polymerization method of the above monomer components. The living radical polymerization method is preferred in the following aspects: while maintaining the simplicity and versatility of the existing radical polymerization method, termination reactions and chain transfer are not likely to occur, and the growth ends grow without inactivation, so it is easy to precisely control the molecular weight distribution and produce a polymer with a uniform composition.

[0254] In the living radical polymerization method, a high-Tg segment can be produced first and then the monomer of the low-Tg segment can be polymerized with the high-Tg segment; alternatively, a low-Tg segment can be produced first and then the monomer of the high-Tg segment can be polymerized with the low-Tg segment.

[0255] In the case where (meth)acrylic block copolymer A is an ABA-type triblock copolymer, from the perspective of ease of production, it is preferred to produce the A segment first and then polymerize the monomer of the B segment with the A segment.

[0256] The above-mentioned living radical polymerization method can use a known method without particular limitation. Depending on the method of stabilizing the polymerization growth ends, there are: a method using a transition metal catalyst (ATRP method); a method using a sulfur-based reversible addition-fragmentation chain transfer agent (RAFT agent) (RAFT method); a method using an organotellurium compound (TERP method), etc. Among these methods, from the perspective of the diversity of monomers that can be used, the ease of molecular weight control, and the fact that metals do not remain in the solvent-based adhesive composition, etc., the RAFT method is preferred.

[0257] The above-mentioned RAFT method can use a known method without particular limitation. For example, it has the following steps: Step 1, polymerize the monomer components using a RAFT agent to prepare a first segment (first RAFT polymerization); and Step 2, further add / polymerize a monomer component with a different monomer composition from that in Step 1 to the first segment obtained in Step 1 and add a second segment to the first segment (second RAFT polymerization). After the second RAFT polymerization, the 3rd, 4th,... RAFT polymerizations can be carried out in the same manner as the second RAFT polymerization to further add the 3rd, 4th,... segments.

[0258] The above-mentioned Step 1 and Step 2 can be carried out using known and conventional methods. For example, solution polymerization methods, emulsion polymerization methods, bulk polymerization methods, polymerization methods based on heat and active energy ray irradiation (thermal polymerization methods, active energy ray polymerization methods), etc. can be cited. Among them, in terms of transparency, water resistance, cost, etc., the solution polymerization method is preferred. It should be noted that from the perspective of suppressing polymerization inhibition caused by oxygen, it is preferred to carry out the polymerization while avoiding contact with oxygen. For example, it is preferred to carry out the polymerization under a nitrogen atmosphere.

[0259] When the (meth)acrylic block copolymer A is an ABA type triblock copolymer, it is preferably prepared by preparing the A block in the above-mentioned step 1 and adding the B block to the obtained A block in the above-mentioned step 2. In this case, a high-Tg block is preferably used as the A block and a low-Tg block is preferably used as the B block.

[0260] As the above-mentioned RAFT agent, a known substance can be used without particular limitation. For example, compounds (trithiocarbonate, dithioester, dithiocarbonate) represented by the following formula (1), formula (2), or formula (3) are preferred.

[0261]

[0262]

[0263] In formula (1), formula (2), or formula (3) [formulas (1) to (3)], R 1a and R 1b are the same or different and represent a hydrogen atom, a hydrocarbon group, or a cyano group. R 1c represents a hydrocarbon group optionally having a cyano group. Regarding the hydrocarbon groups as the above-mentioned R 1a , R 1b and R 1c , for example, hydrocarbon groups having 1 to 20 carbon atoms (linear, branched, or cyclic saturated or unsaturated hydrocarbon groups, etc.) can be mentioned. Among them, hydrocarbon groups having 1 to 12 carbon atoms are preferred. As the above-mentioned hydrocarbon groups, specifically, for example, linear, branched, or cyclic alkyl groups having 1 to 12 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, dodecyl, octadecyl; aryl groups having 6 to 12 carbon atoms such as phenyl; arylalkyl groups having a total of 7 to 10 carbon atoms such as benzyl and phenethyl can be mentioned. Regarding the hydrocarbon groups having a cyano group as the above-mentioned R 1c , for example, groups obtained by substituting 1 to 3 hydrogen atoms of the above-mentioned hydrocarbon groups with cyano groups can be mentioned.

[0264] In formulas (1) to (3), R 2 represents a hydrocarbon group or a group obtained by substituting a part of the hydrogen atoms of the hydrocarbon group with a carboxyl group (for example, carboxyalkyl). As the above-mentioned hydrocarbon group, for example, hydrocarbon groups having 1 to 20 carbon atoms (linear, branched, or cyclic saturated or unsaturated hydrocarbon groups, etc.) can be mentioned. Among them, hydrocarbon groups having 1 to 12 carbon atoms are preferred. As the hydrocarbon group, specifically, for example, linear, branched, or cyclic alkyl groups having 1 to 12 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, cyclohexyl, dodecyl, octadecyl; arylalkyl groups having a total of 7 to 10 carbon atoms such as benzyl and phenethyl can be mentioned.

[0265] In the RAFT method, polymerization is carried out by reacting the raw material monomers in such a way that they are inserted into the sulfur atom of the RAFT agent shown in (1) to (3) and the methylene group adjacent to the sulfur atom.

[0266] Most of the aforementioned RAFT agents are commercially available. Those that are not commercially available can be easily synthesized using well-known and commonly used methods. It should be noted that in the present invention, one type of RAFT agent can be used alone, or two or more types can be used in combination.

[0267] Examples of the RAFT agent include trithiocarbonate esters such as dibenzyl trithiocarbonate and S-cyanomethyl-S-dodecyl trithiocarbonate; dithioester compounds such as cyanoethyl dithiopropionate, benzyl dithiopropionate, benzyl dithiobenzoate, and acetoxyethyl dithiobenzoate; dithiocarbonate esters such as O-ethyl-S-(1-phenylethyl) dithiocarbonate, O-ethyl-S-(2-propoxyethyl) dithiocarbonate, and O-ethyl-S-(1-cyano-1-methylethyl) dithiocarbonate. Among them, trithiocarbonate esters are preferred, and trithiocarbonate esters having a left-right symmetric structure in formula (1) are more preferred. Dibenzyl trithiocarbonate and bis{4-[ethyl-(2-acetoxyethyl)carbamoyl]benzyl} trithiocarbonate are particularly preferred.

[0268] The aforementioned step 1 can be carried out by polymerizing the monomer components in the presence of a RAFT agent. Regarding the amount of the RAFT agent used in step 1, relative to 100 parts by weight of the total amount of the monomer components, it is usually 0.05 to 20 parts by weight, preferably 0.05 to 10 parts by weight. If the amount is such, it is easy to control the reaction and also easy to control the weight-average molecular weight of the resulting segments.

[0269] The aforementioned step 2 can be carried out by adding monomer components to the polymerization reaction mixture obtained in the aforementioned step 1 and further polymerizing.

[0270] The RAFT method is preferably carried out in the presence of a polymerization initiator. Examples of the polymerization initiator include common organic polymerization initiators. Specifically, peroxides and azo compounds can be cited. Among these, azo compounds are preferred. The polymerization initiator can be used alone or two or more types can be used.

[0271] Examples of peroxide-based polymerization initiators include benzoyl peroxide and tert-butyl peroxy maleate.

[0272] Examples of the azo compound include: 2,2'-azobisisobutyronitrile, 2,2'-azobis(4-methoxy-2,4-dimethylvaleronitrile), 2,2'-azobis(2-cyclopropylpropionitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 1,1'-azobis(cyclohexane-1-carbonitrile), 2-(carbamoylazo)isobutyronitrile, 2-phenylazo-4-methoxy-2,4-dimethylvaleronitrile, 2,2'-azobis(2-amidinopropane) dihydrochloride, 2,2'-azobis(N,N'-dimethylisobutylamidine), 2,2'-azobis(isobutyramide) dihydrate, 4,4'-azobis(4-cyanopentanoic acid), 2,2'-azobis(2-cyanopropanol), dimethyl 2,2'-azobis(2-methylpropionate), 2,2'-azobis[2-methyl-N-(2-hydroxyethyl)propionamide].

[0273] Regarding the amount of the polymerization initiator, it is generally 0.001 to 2 parts by weight, preferably 0.002 to 1 part by weight, relative to 100 parts by weight of the total amount of the monomer components. If the amount is such, it is easy to control the weight-average molecular weight of the resulting chain segment.

[0274] The RAFT method may be bulk polymerization without using a polymerization solvent, but preferably a polymerization solvent is used. Examples of the polymerization solvent include: aromatic hydrocarbons such as benzene, toluene, and xylene; aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane; cycloaliphatic hydrocarbons such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane; halogenated hydrocarbons such as chloroform, carbon tetrachloride, 1,2-dichloroethane, and chlorobenzene; ethers such as diethyl ether, diisopropyl ether, 1,2-dimethoxyethane, dibutyl ether, tetrahydrofuran, dioxane, anisole, phenetole, and diphenyl ether; esters such as ethyl acetate, propyl acetate, butyl acetate, and methyl propionate; ketones such as acetone, methyl ethyl ketone, diethyl ketone, methyl isobutyl ketone, and cyclohexanone; amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and N-methylpyrrolidone; nitriles such as acetonitrile and benzonitrile; sulfoxides such as dimethyl sulfoxide and sulfolane. The polymerization solvent may be used alone or in combination of two or more.

[0275] Regarding the amount of the polymerization solvent, there is no particular limitation. For example, relative to 1 g of the monomer component, it is preferably 0.01 mL or more, more preferably 0.05 mL or more, further preferably 0.1 mL or more, preferably 50 mL or less, more preferably 10 mL or less, and further preferably 1 mL or less.

[0276] The reaction temperature under the RAFT method is usually 60 to 120 °C, preferably 70 to 110 °C, and is usually carried out under an inert gas atmosphere such as nitrogen. This reaction can be carried out under any condition of normal pressure, increased pressure, and reduced pressure, and is usually carried out under normal pressure. In addition, the reaction time is usually 1 to 20 hours, preferably 2 to 14 hours.

[0277] The polymerization reaction conditions of the above RAFT method can be applied to Process 1 and Process 2 respectively.

[0278] After the polymerization reaction is completed, the target (meth)acrylic block copolymer A can be separated from the obtained reaction mixture by using common separation and purification means such as removing the used solvent and residual monomers.

[0279] When preparing the high-Tg segment or low-Tg segment of the (meth)acrylic block copolymer A in the above-mentioned Process 1, the weight-average molecular weight (Mw) of the high-Tg segment or low-Tg segment is not particularly limited, preferably 10,000 to 1,000,000, more preferably 50,000 to 500,000, and further preferably 100,000 to 300,000. The Mw of the high-Tg segment or low-Tg segment within this range is suitable for the effects of the present invention described above.

[0280] When there are two or more high-Tg segments or low-Tg segments in the (meth)acrylic block copolymer A, the aforementioned Mw is the sum of their Mws.

[0281] The weight-average molecular weight (Mw) of the (meth)acrylic block copolymer A is not particularly limited, preferably 200,000 or more, more preferably 300,000 to 5,000,000, and further preferably 400,000 to 2,500,000. The Mw of the (meth)acrylic block copolymer A within this range is suitable for the effects of the present invention described above.

[0282] The molecular weight distribution (Mw / Mn) of the (meth)acrylic block copolymer A is not particularly limited, preferably greater than 1, more preferably 1.5 or more, further preferably 2 or more, particularly preferably 2.5 or more, preferably 5 or less, more preferably 4.5 or less, further preferably 4 or less, and particularly preferably 3.5 or less.

[0283] It should be noted that the above weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) are measured by the GPC method.

[0284] Regarding the content ratio of the high-Tg segment in the (meth)acrylic block copolymer A, in 100% by weight of the whole (meth)acrylic block copolymer A, it is preferably 10% by weight or more, more preferably 20% by weight or more, further preferably 25% by weight or more, particularly preferably 30% by weight or more, preferably 95% by weight or less, more preferably 90% by weight or less, and further preferably 85% by weight or less.

[0285] Regarding the content ratio of the low-Tg segment in the (meth)acrylic block copolymer A, in 100% by weight of the whole (meth)acrylic block copolymer A, it is preferably 5% by weight or more, more preferably 10% by weight or more, further preferably 15% by weight or more, preferably 60% by weight or less, more preferably 50% by weight or less, further preferably 40% by weight or less, and particularly preferably 30% by weight or less.

[0286] The content ratio of each of the foregoing segments and their ratios can be calculated based on each segment obtained in each step of the foregoing RAFT method or the weight-average molecular weight (Mw) of the (meth)acrylic block copolymer A, and can be controlled using the feeding ratio of the monomers when forming each segment and the polymerization rate of each monomer, etc.

[0287] There is no particular limitation on the content of the (meth)acrylic block copolymer A in the solvent-based adhesive composition A. From the perspective of obtaining excellent processability at room temperature (25°C) and excellent height difference absorbability in the region exceeding 50°C, it is preferably 50% by weight or more (for example, 50 to 100% by weight), more preferably 60% by weight or more, further preferably 80% by weight or more, and particularly preferably 90% by weight or more, relative to the total amount (total weight, 100% by weight) of the solvent-based adhesive composition A.

[0288] (Solvent)

[0289] Since the polymer in the third method is solid, the solvent-based adhesive composition is a solution in which the polymer is dissolved in an organic solvent. For example, a polymer solution can be obtained by solution polymerization of the monomer components. A polymer solution can be prepared by dissolving the solid polymer in an organic solvent.

[0290] As the solvent, ethyl acetate, toluene, etc. are generally used. The solution concentration is usually about 20 to 80% by weight.

[0291] As a polymerization initiator for solution polymerization of monomer components, thermal polymerization initiators such as azo initiators, peroxide initiators, and redox initiators obtained by combining peroxides and reducing agents (for example, combinations of persulfates and sodium bisulfite, combinations of peroxides and sodium ascorbate) are preferably used. There is no particular limitation on the amount of the polymerization initiator used. For example, relative to 100 parts by weight of the total amount of monomer components forming the polymer, it is preferably about 0.005 to 5 parts by weight, more preferably about 0.02 to 3 parts by weight.

[0292] (Colorant)

[0293] The solvent-based adhesive composition for forming the adhesive layer of the third mode may contain a colorant. In particular, the solvent-based adhesive composition for forming the first adhesive layer 1 preferably further contains a colorant. If the solvent-based adhesive composition for forming the first adhesive layer 1 contains a colorant, it is preferable in the following aspects: the light transmittance of the first adhesive layer 1 to visible light is reduced, and a scheme in which the aforementioned T1 and the aforementioned T2 satisfy T1 < T2 is formed. By encapsulating the metal wiring layer 6 and the LED chip of the self-luminous display device (Mini / Micro LED display device) of the present embodiment with the first adhesive layer 1 having reduced light transmittance to visible light and imparted light-shielding properties, reflection caused by metal wiring and the like can be prevented, color mixing between LED chips can be prevented, and the contrast of the image can be improved.

[0294] The colorant can be a dye or a pigment as long as it can be dissolved or dispersed in the solvent-based adhesive composition. From the perspective that low haze can be achieved with a small amount of addition and it is easy to be uniformly distributed without sedimentation like a pigment, a dye is preferred. In addition, from the perspective of obtaining high color development with a small amount of addition, a pigment is also preferred. When a pigment is used as the colorant, a pigment with low conductivity or no conductivity is preferred. In addition, when a dye is used, it is preferably used in combination with an antioxidant and the like described later.

[0295] As the colorant contained in the solvent-based adhesive composition in the third mode, in addition to the ultraviolet light-transmitting colorant described above for the first mode, an ultraviolet light-absorbing colorant is also included.

[0296] Examples of the ultraviolet light-transmitting black pigment include "9050BLACK", "UVBK-0001", etc. manufactured by TOKUSHIKI CO., Ltd. Examples of the ultraviolet light-absorbing black dye include "VALIFAST BLACK 3810", "NUBIAN Black PA-2802", etc. manufactured by ORIENT CHEMICAL INDUSTRIES CO., LTD. Examples of the ultraviolet light-absorbing black pigment include carbon black, titanium black, etc.

[0297] Regarding the content of the colorant in the solvent-based adhesive composition, for example, it is about 0.01 to 20 parts by weight relative to 100 parts by weight of the total monomers, and it can be appropriately set according to the type of the colorant, the hue of the adhesive layer, the light transmittance, etc. The colorant can be added to the composition as a solution or dispersion dissolved or dispersed in an appropriate solvent.

[0298] (Crosslinking agent)

[0299] The solvent-based adhesive composition of the third mode may contain a crosslinking agent capable of crosslinking with the above polymer. It should be noted that in the case where the solvent-based adhesive composition contains a (meth)acrylic block copolymer, the adhesive layer of the third mode has sufficient shape stability, so it may not contain a crosslinking agent.

[0300] In the third mode, when the solvent-based adhesive composition contains a crosslinking agent, as the crosslinking agent, similar to that described for the second mode above, isocyanate-based crosslinking agents and epoxy-based crosslinking agents are preferred.

[0301] In the third mode, when the solvent-based adhesive composition contains a crosslinking agent, its content is about 0.01 to 5 parts by weight relative to 100 parts by weight of the polymer, and it can be 0.05 parts by weight or more, 0.1 parts by weight or more, or 0.2 parts by weight or more, and can be 3 parts by weight or less, 2 parts by weight or less, or 1 part by weight or less.

[0302] (Other components)

[0303] The solvent-based adhesive composition of the third mode may further contain oligomers, tackifiers, silane coupling agents, chain transfer agents, plasticizers, softeners, anti-degradants, fillers, antioxidants, surfactants, antistatic agents, etc. in addition to the above components.

[0304] (Optical laminate)

[0305] In the present embodiment, the optical laminate 10 to 12 can be prepared by laminating the second adhesive layer 2 on the surface 3b of the substrate 3 and further laminating the first adhesive layer 1.

[0306] [First mode]

[0307] There is no particular limitation on the method of laminating the second adhesive layer 2 of the first mode on the surface 3b of the substrate 3. For example, it can be carried out by coating the aforementioned photocurable adhesive composition on a release film and forming it into a sheet, performing photocuring to produce the sheet-like second adhesive layer 2, and then laminating it on the surface 3b of the substrate 3.

[0308] There is no particular limitation on the method of further laminating the first adhesive layer 1 on the second adhesive layer 2 laminated on the substrate 3. For example, the sheet-like first adhesive layer 1 can be produced by coating the above-mentioned photocurable adhesive composition on a release film and forming it into a sheet shape, followed by photocuring, and then laminating it on the second adhesive layer laminated on the surface 3b of the substrate 3.

[0309] By coating the photocurable adhesive composition in a sheet (layer) form on a release film and irradiating ultraviolet rays to the coating film of the adhesive composition on the release film for photocuring, the first adhesive layer or the second adhesive layer of the first method can be obtained. When performing photocuring, it is preferable to further attach a release film on the surface of the coating film and irradiate the photocurable adhesive composition with ultraviolet rays in a state of being sandwiched between two release films to prevent polymerization inhibition caused by oxygen. Before photocuring, the sheet-like coating film can be heated for the purpose of removing the solvent or dispersion medium of the colorant. When removing the solvent or the like based on heating, it is preferably carried out before attaching the release film.

[0310] As the film substrate of the release film, films formed of various resin materials can be used. As the resin materials, there can be mentioned: polyester resins such as polyethylene terephthalate and polyethylene naphthalate, acetate resins, polyethersulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, polyvinyl chloride resins, polyvinylidene chloride resins, polystyrene resins, polyvinyl alcohol resins, polyarylate resins, polyphenylene sulfide resins, etc. Among these, polyester resins such as polyethylene terephthalate are particularly preferred. The thickness of the film substrate is preferably 10 to 200 μm, more preferably 25 to 150 μm. As the material of the release layer, there can be mentioned: silicone-based release agents, fluorine-based release agents, long-chain alkyl-based release agents, fatty acid amide-based release agents, etc. The thickness of the release layer is generally about 10 to 2000 nm.

[0311] As the method of coating the adhesive composition on the release film, various methods such as roll coating, roll kiss coating, gravure coating, reverse coating, roll brush, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, die coater can be used.

[0312] There is no particular limitation on the thickness of the first adhesive layer 1. It may be appropriately set in such a way that the light-emitting elements arranged on the display panel described below are sufficiently encapsulated while the upper part (image display side) of the light-emitting elements is covered by the second adhesive layer 2. For example, it is adjusted such that the thickness of the first adhesive layer is 0.1 to 2.0 times, preferably 0.2 to 1.5 times, and more preferably 0.3 to 1.2 times the height of the light-emitting element. Specifically, the thickness of the first adhesive layer is, for example, about 10 to 300 μm, preferably 15 to 200 μm. Specifically, the thickness of the first adhesive layer may be 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. In addition, when the first adhesive layer contains an ultraviolet-transmissive colorant, even when the thickness of the first adhesive layer is large, the photocurable adhesive composition can be photocured uniformly in the thickness direction. The thickness of the first adhesive layer is 300 μm or less, and may be 250 μm or less or 200 μm or less.

[0313] There is no particular limitation on the thickness of the second adhesive layer 2. It may be appropriately set in such a way that the light-emitting elements arranged on the display panel described below are sufficiently encapsulated while allowing sufficient light to pass through the upper part (image display side) of the light-emitting elements. Specifically, the thickness of the second adhesive layer is, for example, about 1 to 500 μm, more preferably 10 to 300 μm, and further preferably 15 to 200 μm. Specifically, the thickness of the second adhesive layer may be 1 μm or more, 10 μm or more, 15 μm or more, 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. In addition, the thickness of the second adhesive layer may be 400 μm or less, 300 μm or less, 250 μm or less, or 200 μm or less.

[0314] There is no particular limitation on the total thickness of the first adhesive layer 1 and the second adhesive layer 2. It may be appropriately set in such a way that the light-emitting elements arranged on the display panel described below can be sufficiently encapsulated and the thickness reaches above the height of the light-emitting element. For example, it is adjusted such that the thickness of the adhesive layer is 1.0 to 4.0 times, preferably 1.1 to 3.0 times, more preferably 1.2 to 2.5 times, and further preferably 1.3 to 2.0 times the height of the light-emitting element. Specifically, the total thickness of the first adhesive layer 1 and the second adhesive layer 2 is, for example, about 11 to 800 μm, and may be 20 μm or more, 30 μm or more, 40 μm or more, or 50 μm or more. In addition, the total thickness of the first adhesive layer 1 and the second adhesive layer 2 is, for example, 700 μm or less, and may be 600 μm or less, 500 μm or less, or 400 μm or less.

[0315] There is no particular limitation on the ratio of the thickness of the aforementioned second adhesive layer to the thickness of the aforementioned first adhesive layer (thickness of the second adhesive layer / thickness of the first adhesive layer). It may be appropriately set in such a manner that the light-emitting elements arranged on the display panel described later are sufficiently encapsulated while the upper part (image display side) of the light-emitting elements is covered by the second adhesive layer. Specifically, (thickness of the second adhesive layer / thickness of the first adhesive layer) may be, for example, about 1.0 to 5.0, preferably 1.2 to 4.0, and more preferably 1.3 to 3.0.

[0316] By irradiating ultraviolet rays to the photocurable adhesive composition coated in layers on the release film, active species are generated from the photoinitiator, and the photopolymerizable compound undergoes polymerization. Along with the increase in the polymerization rate (reduction of unreacted monomers), the liquid photocurable adhesive composition forms a solid (certain shape) adhesive layer. As the light source for ultraviolet irradiation, there is no particular limitation as long as it can irradiate light in the wavelength range to which the photoinitiator contained in the photocurable adhesive composition is sensitive, and an LED light source, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a metal halide lamp, a xenon lamp, etc. can be used.

[0317] The cumulative light amount of the irradiated light is, for example, 100 to 5000 mJ / cm 2 or so. The polymerization rate (non-volatile component) of the adhesive layer formed from the photocured product of the photocurable adhesive composition is preferably 80% or more, more preferably 85% or more, and further preferably 90% or more. The polymerization rate may be 93% or more or 95% or more. In order to reduce the non-volatile components, the adhesive layer may be heated to remove volatile components such as residual monomers, unreacted photoinitiators, and solvents.

[0318] When release films are provided on both sides of the adhesive layer, the thickness of the release film on one side and the thickness of the release film on the other side may be the same or different. The peeling force when peeling the release film temporarily adhered to one surface from the adhesive layer and the peeling force when peeling the release film temporarily adhered to the other surface from the adhesive layer may be the same or different. In the case where the peeling forces of the two are different, first, the release film with a relatively small peeling force (light release film) is peeled from the second adhesive layer 2 and the second adhesive layer 2 is adhered to the surface 3b of the substrate 3, and then the release film with a relatively large peeling force (heavy release film) is peeled from the second adhesive layer 2 to expose the second adhesive layer. Then, the light release film is peeled from the first adhesive layer 1, and the first adhesive layer 1 is pasted on the exposed second adhesive layer, whereby an optical laminate having the first adhesive layer and the second adhesive layer in the first mode can be produced.

[0319] In addition, by coating the aforementioned photocurable adhesive composition on the surface 3b of the substrate 3, forming it into a sheet, attaching a release film to the surface of the coating film, and irradiating ultraviolet rays, the second adhesive layer is laminated on the substrate 3, and the same procedure as above is carried out, whereby an optical laminate having a first adhesive layer and a second adhesive layer in the first mode can also be produced.

[0320] When a colorant is contained in the first adhesive layer and / or the second adhesive layer, it has light absorption for visible light. The visible light transmittance of the optical laminate in the first mode is, for example, 80% or less, and may be 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less.

[0321] In the first mode, the visible light transmittance T1 of the first adhesive layer is not particularly limited, and is, for example, 80% or less, and may be 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less. By making the visible light transmittance T1 of the first adhesive layer 80% or less, it is easy to make the transmittance lower than the visible light transmittance T2 of the second adhesive layer. As described above, by encapsulating between the metal wiring and the light-emitting element of the self-luminous display device, reflection of the metal wiring and the like can be prevented, color mixing between the light-emitting elements can be prevented, and the contrast can be improved. In addition, as described above, when a colorant having less absorption of ultraviolet rays than visible light is used in the first adhesive layer, the average transmittance T of the first adhesive layer at a wavelength of 330 to 400 nm UV will be greater than the average transmittance T at a wavelength of 400 to 700 nm VIS . The average transmittance T of the first adhesive layer at a wavelength of 400 to 700 nm VIS is, for example, 80% or less, and may be 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, or 10% or less. The average transmittance T of the first adhesive layer at a wavelength of 330 to 400 nm UV is preferably 5% or more, and may be 10% or more, 15% or more, 20% or more, or 25% or more. The difference T UV between T VIS and T UV -T VIS can be 3% or more, 5% or more, 8% or more, or 10% or more.

[0322] In the first mode, the visible light transmittance T2 of the second adhesive layer is not particularly limited, and is, for example, 85 to 100%, and may be 88% or more, 90% or more, or 92% or more. As described above, by covering the upper part (image display side) of the light-emitting element of the self-luminous display device with the second adhesive layer having high transmittance, the luminous efficiency is improved.

[0323] In the first mode, the shear storage modulus G'25°C of the first adhesive layer and the second adhesive layer at a temperature of 25°C is, for example, about 10 to 1000 kPa, and can be 30 kPa or more, 50 kPa or more, 70 kPa or more, or 100 kPa or more, and can be 700 kPa or less, 500 kPa or less, 300 kPa or less, or 200 kPa or less. The shear storage modulus G'85°C of the adhesive layer at a temperature of 85°C is, for example, about 3 to 300 kPa, and can be 5 kPa or more, 7 kPa or more, or 10 kPa or more, and can be 200 kPa or less, 150 kPa or less, or 100 kPa or less. If the shear storage modulus of the adhesive layer is within the above range, appropriate flexibility and adhesiveness can be balanced. The shear storage modulus is a measured value based on dynamic viscoelasticity measurement at a frequency of 1 Hz.

[0324] [Second mode]

[0325] The optical laminate having the adhesive layer of the second mode can be prepared as follows: Coating the photocurable adhesive composition of the second mode on the release film, drying and removing the solvent as needed to form the second adhesive layer and pasting it on the surface 3b of the substrate 3. Then, coating the photocurable adhesive composition of the second mode on the release film, drying and removing the solvent as needed to form the first adhesive layer, and then pasting it on the second adhesive layer laminated on the surface 3b of the substrate 3, thereby preparing it.

[0326] In addition, the optical laminate having the adhesive layer of the second mode can also be prepared as follows: Coating the photocurable adhesive composition of the second mode on the surface 3b of the substrate 3, drying and removing the solvent as needed, thereby forming the second adhesive layer. Then, coating the photocurable adhesive composition of the second mode on the release film, drying and removing the solvent as needed to form the first adhesive layer, and then pasting it on the second adhesive layer laminated on the surface 3b of the substrate 3, thereby preparing it.

[0327] When the photocurable adhesive composition contains a solvent, it is preferable to dry the solvent after coating the adhesive composition. As the drying method, an appropriate method can be appropriately adopted according to the purpose. The heating drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. The drying time can be appropriately adopted as an appropriate time. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, and particularly preferably 10 seconds to 10 minutes.

[0328] After applying the photocurable adhesive composition, heating is carried out as needed, whereby a crosslinked structure is introduced into the polymer. The heating temperature and heating time can be appropriately set according to the type of crosslinking agent used, and are usually in the range of 20°C to 160°C for about 1 minute to 7 days. The heating for drying the solvent can also serve as the heating for crosslinking. The introduction of the crosslinked structure does not necessarily require heating.

[0329] The first adhesive layer and the second adhesive layer of the second mode preferably have the same thickness (the respective thicknesses, total thickness, and thickness ratio of the first adhesive layer and the second adhesive layer), light transmittance, and shear storage modulus as the first adhesive layer and the second adhesive layer of the first mode. Since the first adhesive layer and the second adhesive layer of the second mode are not photocured, the photopolymerizable compound is contained in an unreacted state. That is, the first adhesive layer and the second adhesive layer of the second mode are photocurable adhesive layers containing a polymer, a photopolymerizable compound, a photoinitiator, and a colorant as required.

[0330] The optical laminate having the photocurable first adhesive layer and / or second adhesive layer of the second mode can be photocured by irradiating ultraviolet rays after being attached to a display panel described later. By photocuring, the adhesive force between the optical laminate and the display panel can be changed. For example, since the adhesive layer before photocuring has high flexibility, it can fill the uneven shapes and height differences formed by the light-emitting elements arranged on the display panel, and the adhesive force and bonding reliability to the display panel can be improved after photocuring.

[0331] As the active ray for photocuring the adhesive layer, ultraviolet rays can be used. Similar to the adhesive layer of the first mode, when a ultraviolet ray-permeable colorant is used, since the transmittance of ultraviolet rays is larger than that of visible light, even when the thickness of the adhesive layer is large, curing inhibition during photocuring can be suppressed.

[0332] The optical laminate having the first adhesive layer and / or second adhesive layer of the first mode and the second mode containing the above ultraviolet ray-permeable colorant has light absorption for visible light. The optical laminates of the first mode and the second mode desirably have a maximum value of transmittance at 350 nm to 450 nm.

[0333] The visible light transmittance of the optical laminates of the first mode and the second mode is, for example, 80% or less, and can be 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less.

[0334] [Third mode]

[0335] The optical laminate having the adhesive layer of the third mode can be prepared as follows: The solvent-based adhesive composition of the third mode is coated on a release film, and the solvent is dried and removed as needed to form a second adhesive layer, which is then pasted onto the surface 3b of the substrate 3. Then, the solvent-based adhesive composition of the third mode is coated on the release film, and the solvent is dried and removed as needed to form a first adhesive layer, which is then pasted onto the second adhesive layer laminated on the surface 3b of the substrate 3, thereby preparing the optical laminate.

[0336] In addition, the optical laminate having the adhesive layer of the third mode can also be prepared as follows: The solvent-based adhesive composition of the third mode is coated on the surface 3b of the substrate 3, and the solvent is dried and removed as needed, thereby forming a second adhesive layer. Then, the solvent-based adhesive composition of the third mode is coated on the release film, and the solvent is dried and removed as needed to form a first adhesive layer, which is then pasted onto the second adhesive layer laminated on the surface 3b of the substrate 3, thereby preparing the optical laminate.

[0337] After coating the solvent-based adhesive composition, the solvent is dried. As the drying method, an appropriate method can be appropriately adopted according to the purpose. The heating drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. The drying time can be appropriately adopted as an appropriate time. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 15 minutes, and particularly preferably 10 seconds to 10 minutes.

[0338] After coating the photocurable adhesive composition, heating can be carried out as needed. The heating temperature and heating time can be appropriately set according to the type of crosslinking agent used, and are usually in the range of 20°C to 160°C for about 1 minute to 7 days.

[0339] The first adhesive layer and the second adhesive layer of the third mode preferably have the same thickness (the respective thicknesses, total thickness, and thickness ratio of the first adhesive layer and the second adhesive layer), light transmittance, and shear storage modulus as the first adhesive layer and the second adhesive layer of the first mode.

[0340] In addition, there is no particular limitation on the storage modulus (G’25) at 25°C of the first adhesive layer and / or the second adhesive layer (especially the first adhesive layer) when the solvent-based adhesive composition contains the (meth)acrylic block copolymer A. From the perspective of improving processability at room temperature, it is preferably 1 MPa or more, more preferably 1.5 MPa or more, more preferably 2 MPa or more, more preferably 2.5 MPa or more, more preferably 3 MPa or more. From the perspective of improving adhesion reliability at room temperature, it is preferably 50 MPa or less, more preferably 45 MPa or less, more preferably 40 MPa or less, more preferably 35 MPa or less, more preferably 30 MPa or less.

[0341] There is no particular limitation on the storage modulus (G’50) at 50°C of the first adhesive layer and / or the second adhesive layer (especially the first adhesive layer) when the solvent-based adhesive composition contains the (meth)acrylic block copolymer A. From the perspective of improving the height difference absorbability in the region above 50°C, it is preferably 0.5 MPa or less, more preferably 0.45 MPa or less, more preferably 0.4 MPa or less, more preferably 0.35 MPa or less, more preferably 0.3 MPa or less. From the perspective of improving the operability in the region above 50°C, it is preferably 0.0001 MPa or more, more preferably 0.0005 MPa or more, more preferably 0.001 MPa or more, more preferably 0.005 MPa or more, more preferably 0.01 MPa or more.

[0342] There is no particular limitation on the ratio (G’25 / G’50) of the storage modulus at 25°C to the storage modulus at 50°C of the first adhesive layer and / or the second adhesive layer (especially the first adhesive layer) when the solvent-based adhesive composition contains the (meth)acrylic block copolymer A. From the perspective of improving processability at room temperature and improving the height difference absorbability in the region above 50°C, it is preferably 3 or more, more preferably 5 or more, more preferably 10 or more, further preferably 15 or more, particularly preferably 20 or more. From the perspectives of adhesion reliability, operability, etc., it is preferably 100 or less, more preferably 95 or less, more preferably 90 or less, further preferably 85 or less, particularly preferably 80 or less.

[0343] It should be noted that the storage modulus (G’25) at 25°C, the storage modulus (G’25) at 50°C, and their ratio (G’25 / G’50) are measured by dynamic viscoelasticity measurement.

[0344] The optical laminate having the first adhesive layer and / or the second adhesive layer in the third mode containing a colorant has light absorption for visible light.

[0345] The visible light transmittance of the optical laminate of the third mode is, for example, 80% or less, and may be 70% or less, 60% or less, 50% or less, 40% or less, 30% or less, 20% or less, 10% or less, or 5% or less.

[0346] In the optical laminate of the present embodiment (the first mode to the third mode), a release film may be provided on the adhesive layer until use. Further, in the optical laminate of the present embodiment (the first mode to the third mode), a surface protection film may be laminated on the surface 3a of the base material 3. The surface protection film is suitable in the following aspects: preventing damage and dirt adhesion during the manufacture, transportation, and shipment of the optical laminate and the optical product including the same.

[0347] In addition to the first adhesive layer 1, the second adhesive layer 2, the base material 3, the release film, and the surface protection film, the optical laminate of the present embodiment (the first mode to the third mode) may have other layers on the surface or between arbitrary layers within the range not impairing the effects of the present invention, such as a base material other than the base material 3, an adhesive layer other than the first adhesive layer 1 and the second adhesive layer 2, an intermediate layer, a primer layer, and the like.

[0348] <Self-luminous display device>

[0349] The self-luminous display device according to the second aspect of the present invention is a display device that arranges a large number of minute light-emitting elements on a wiring substrate and selectively emits light from each light-emitting element by using a light-emission control means connected thereto, so that visual information such as characters, images, and videos can be directly displayed on a display screen by the lighting and extinguishing of each light-emitting element. Examples of the self-luminous display device include Mini / Micro LED display devices and organic EL (electroluminescence) display devices. The optical laminate according to the third aspect of the present invention is particularly suitable for manufacturing Mini / Micro LED display devices.

[0350] Figures 4 to 6 It is a schematic view (cross-sectional view) showing an embodiment of the self-luminous display device (Mini / Micro LED display device) according to the second aspect of the present invention. The Mini / Micro LED display device 20 of the present embodiment includes a display panel in which a plurality of LED chips 7 are arranged on one side of a substrate 5, and an optical laminate 10. The surface of the display panel on which the LED chips 7 are arranged is laminated with the first adhesive layer 1 of the optical laminate 10. In the Mini / Micro LED display device 21, an antireflection treatment and / or an antiglare treatment 4 is performed on the surface 3a of the base material 3 where the second adhesive layer 2 is not laminated. In the Mini / Micro LED display device 22, an antiglare layer 4a is formed as an antiglare treatment on the surface 3a of the base material 3 where the second adhesive layer 2 is not laminated.

[0351] In the present embodiment, a metal wiring layer 6 for sending a light emission control signal to each LED chip 7 is laminated on a substrate 5 of a display panel. Each LED chip 7 that emits light of various colors of red (R), green (G), and blue (B) is alternately arranged on the substrate 5 of the display panel via the metal wiring layer 6. The metal wiring layer 6 is formed of a metal such as copper, and reflects the light emitted by each LED chip 7, reducing the image recognition. In addition, the light emitted by each LED chip 7 of each color of RGB is mixed, reducing the contrast.

[0352] In the Mini / Micro LED display device of the present embodiment, a first adhesive layer 1 encapsulates between each LED chip 7 arranged on the display panel and the metal wiring layer 6. By making the visible light transmittance of the first adhesive layer 1 lower than that of the second adhesive layer 2, sufficient light shielding property is provided in the visible light region. Since the first adhesive layer 1 with higher light shielding property (lower transmittance) encapsulates between each LED chip 7 without gaps, color mixing between each LED chip 7 can be prevented, and the contrast can be improved. In addition, since the first adhesive layer 1 with higher light shielding property (lower transmittance) also encapsulates the surface of the metal wiring layer 6, reflection caused by the metal wiring layer 6 can be prevented.

[0353] In the present embodiment, a second adhesive layer 2 encapsulates the upper part (image display side) of each LED chip 7 arranged on the display panel. By making the visible light transmittance of the second adhesive layer 2 higher than that of the first adhesive layer 1, sufficient transmittance is provided in the visible light region. Since the second adhesive layer 2 with higher transmittance encapsulates the upper part (image display side) of each LED chip 7, absorption of visible light emitted by each LED chip 7 can be suppressed to a low level, the luminous efficiency can be improved, and thus the image can be made brighter. In addition, since there is no need to increase the output power to increase the luminous brightness, power consumption can be suppressed to a low level.

[0354] As described above, the optical laminate of the present embodiment includes a first adhesive layer with higher light-shielding properties (lower transmittance), so even when a metal adherend is laminated on the first adhesive layer, it is possible to prevent reflection and gloss on the metal surface. The reflectivity of the visible light region of the 5° regular reflection of the substrate surface 3a when a metal adherend is laminated on the first adhesive layer of the optical laminate of the present embodiment is preferably 50% or less, more preferably 30% or less, further preferably 15% or less, and particularly preferably 10% or less. The glossiness of the substrate surface 3a when a metal adherend is laminated on the first adhesive layer of the optical laminate of the present embodiment (based on JIS Z 8741-1997) is preferably 100% or less, more preferably 80% or less, further preferably 60% or less, and particularly preferably 50% or less.

[0355] In addition, copper, aluminum, stainless steel, etc. can be used as the above-mentioned metal adherend.

[0356] In addition, in the Mini / Micro LED display device of the present embodiment, when the surface 3a of the substrate 3 is subjected to an anti-reflection treatment and / or an anti-glare treatment 4, the visibility is prevented from being reduced due to reflection of external light, image reflection, etc. at the surface 3a of the substrate, or the aesthetics such as glossiness is adjusted. The Mini / Micro LED display device 22 of the present embodiment has an anti-glare layer 4a formed on the surface 3a of the substrate 3. The average inclination angle θa (°) of the anti-glare layer 4a of the Mini / Micro LED display device 22 of the present embodiment is the same as described above.

[0357] The self-luminous display device of this embodiment may have optical components other than the display panel and the optical laminate. The above-mentioned optical components are not particularly limited, and examples thereof include: polarizing plates, phase difference plates, anti-reflection films, viewing angle adjustment films, optical compensation films, etc. It should be noted that the optical components also include components (decorative films, decorative films, surface protection plates, etc.) that perform the functions of decoration and protection while maintaining the recognizability of the display device and the input device.

[0358] The Mini / Micro LED display device of the present embodiment can be manufactured by bonding a display panel having a plurality of LED chips arranged on one surface of a substrate to the first pressure-sensitive adhesive layer of the optical laminate of the first aspect of the present invention.

[0359] Specifically, the lamination of the optical laminate having the display panel and the first adhesive layer and / or the second adhesive layer in the first mode can be carried out by laminating under heating and / or pressure. In the case of laminating the optical laminate having the display panel and the first adhesive layer and / or the second adhesive layer in the second mode, it can be carried out by photocuring after laminating under heating and / or pressure. The photocuring can be carried out in the same manner as the photocuring of the first adhesive layer and / or the second adhesive layer in the above-mentioned first mode.

[0360] When the first adhesive layer and / or the second adhesive layer is formed of a solvent-based adhesive composition containing a (meth)acrylic block copolymer A, the above-mentioned lamination is preferably carried out by heating and pressing at 50 °C or higher. By heating and pressing at 50 °C or higher, the adhesive layer forms high fluidity, can fully follow the height difference of the LED chips arranged on the substrate, and is closely adhered without gaps. The heating is carried out at 50 °C or higher, preferably at 60 °C or higher, more preferably at 70 °C or higher. There is no particular limitation on the pressure, for example, it is carried out at 1.5 atm or higher, preferably at 2 atm or higher, more preferably at 3 atm or higher. The heating and pressing can be carried out using an autoclave or the like. After the Mini / Micro LED display device manufactured thereby is restored to room temperature (25 °C), the storage modulus of the adhesive layer increases, and the processability and bonding reliability are improved.

[0361] Examples

[0362] Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples. It should be noted that various characteristics in the following production examples are evaluated or measured by the following methods.

[0363] (Measurement of surface shape)

[0364] A glass plate (thickness 1.3 mm) manufactured by Matsunami Glass Industry Co., Ltd. is laminated on the surface of the antiglare film where the antiglare layer is not formed with an adhesive, and the surface shape of the antiglare layer is measured under the condition of a cut-off value of 0.8 mm using a high-precision micro shape measuring instrument (trade name; Surfcorder ET4000, manufactured by Kosaka Laboratory Ltd.), and the average inclination angle θa is obtained. It should be noted that the above-mentioned high-precision micro shape measuring instrument automatically calculates the above-mentioned average inclination angle θa. The above-mentioned average inclination angle θa is based on JIS B 0601 (1994 edition).

[0365] (Haze)

[0366] Using the method specified in JIS K 7136, the haze value is measured by setting the light to enter the haze meter (manufactured by Murakami Color Research Institute Co., Ltd., trade name "HN-150") from the antiglare surface of the antiglare film.

[0367] (Visible light transmittance of the adhesive sheet)

[0368] Peel the release film on one side from the adhesive sheet, and attach an alkali-free glass to the exposed surface. Then, peel the release film on the other side from the adhesive sheet to obtain a specimen with the adhesive sheet attached to the alkali-free glass plate. Using this specimen, measure the transmission spectrum of the evaluation sample using a visible-ultraviolet spectrophotometer (manufactured by Hitachi High-Technologies Corporation, trade name "U-4100"). Taking the alkali-free glass (single substance) as the baseline, the ratio of the transmittance (transmitted light amount) of the evaluation sample to the transmittance (transmitted light amount) of the alkali-free glass is defined as the transmittance of the adhesive sheet. Based on the transmission spectrum of the adhesive sheet, calculate the transmittance T at a wavelength of 550 nm. VIS 。

[0369] (Visible light transmittance of the antiglare film)

[0370] Place the antiglare film on the spectrophotometer U4100 (manufactured by Hitachi High-Technologies Corporation) in such a way that light enters from the antiglare layer side, and measure the transmittance (%) in the visible light region. This transmittance is the Y value measured using a 2-degree field of view (C light source) of JIS Z 8701 and corrected for visual sensitivity.

[0371] Production Example 1

[0372] (Preparation of the antiglare film)

[0373] As the resin contained in the antiglare layer, prepare 100 parts by weight of an ultraviolet curable urethane acrylate resin (manufactured by DIC Corporation, trade name "UNIDIC 17-806", solid content 80%). With respect to 100 parts by weight of the resin solid content of the aforementioned resin, mix 14 parts by weight of styrene crosslinked particles (manufactured by Soken Chemical & Engineering Co., Ltd., trade name "MX-350H", weight average particle diameter: 3.5 μm, refractive index 1.59) as light diffusing fine particles, 2.5 parts by weight of synthetic montmorillonite belonging to organic clay (manufactured by KUNIMINE INDUSTRIES CO., LTD., trade name "SUMECTON SAN") as a thixotropy imparting agent, 5 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, trade name "OMNIRAD907"), and 0.5 parts by weight of a leveling agent (manufactured by DIC Corporation, trade name "MEGAFAC F-556", solid content 100%). Dilute this mixture with a toluene / ethyl acetate mixed solvent (weight ratio 90 / 10) to a solid content concentration of 30% by weight to prepare a light diffusing element forming material (coating liquid).

[0374] On one side of a triacetyl cellulose (TAC) film (manufactured by Fujifilm Corporation, product name "TG60UL", thickness: 60 μm) that can function as a protective layer, an antiglare layer forming material (coating solution) was coated using a rod coater to form a coating film. Then, the transparent TAC film substrate with the coating film formed thereon was transported to a drying process. In the drying process, the aforementioned coating film was dried by heating at 110 °C for 1 minute. Then, ultraviolet rays with a cumulative light amount of 300 mJ / cm 2 were irradiated with a high-pressure mercury lamp to cure the aforementioned coating film, and a light diffusion element with a thickness of 5.0 μm was formed on one side of the TAC film to obtain an antiglare film 1. The haze value of the antiglare film 1 was 42%. The θa (°) of the antiglare layer of the antiglare film 1 was 1.22. The visible light transmittance of the antiglare film 1 was 90%.

[0375] Production Example 2

[0376] (Preparation of antiglare film)

[0377] As light diffusing particles, 14 parts by weight of amorphous silica (manufactured by Fuji Silysia chemical Ltd., trade name "SYLOPHOBIC 100", weight average particle diameter: 2.6 μm) was added to make the thickness after curing treatment 7.0 μm. Otherwise, a light diffusion element was formed on one side of the TAC film in the same manner as in Production Example 1 to obtain an antiglare film 2. The haze value of the antiglare film 2 was 11%. The θa (°) of the antiglare layer of the antiglare film 2 was 1.43. The visible light transmittance of the antiglare film 2 was 91%.

[0378] Production Example 3

[0379] (Preparation of antiglare film)

[0380] As the resin contained in the antiglare layer forming material, 100 parts by weight of an ultraviolet curable urethane acrylate resin (manufactured by DIC Corporation, trade name “UNIDIC 17-806”, solid content: 80%) was prepared. With respect to 100 parts by weight of the resin solid content of the aforementioned resin, as the antiglare layer forming particles, 7 parts by weight of amorphous silica (manufactured by FujiSilysia chemical Ltd., trade name “SYLOPHOBIC 702”), 6.5 parts by weight of amorphous silica (manufactured by FujiSilysia chemical Ltd., trade name “SYLOPHOBIC 100”), 5 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, trade name “OMNIRAD184”), and 0.5 parts by weight of a leveling agent (manufactured by DIC Corporation, trade name “MEGAFAC F-556”) were mixed. The mixture was diluted with toluene to a solid content concentration of 30% to prepare an antiglare layer forming material (coating liquid).

[0381] As the light transmissive substrate, a transparent plastic film substrate (TAC film, manufactured by Fuji Film Corporation, trade name “TD80UL”, thickness: 80 μm) was prepared. Using a bar coater, the aforementioned antiglare layer forming material (coating liquid) was formed into a coating film on one side of the aforementioned transparent plastic film substrate. Then, the transparent plastic film substrate having the coating film formed thereon was conveyed to a drying process. In the drying process, the aforementioned coating film was dried by heating at 110 °C for 1 minute. Then, ultraviolet rays with an accumulated light quantity of 300 mJ / cm 2 were irradiated with a high-pressure mercury lamp to cure the aforementioned coating film, forming an antiglare layer with a thickness of 5.0 μm, and obtaining an antiglare film 3. The θa (°) of the antiglare layer of the antiglare film 3 was 3.5. The visible light transmittance of the antiglare film 3 was 91%.

[0382] Production Example 4

[0383] (Preparation of antiglare film)

[0384] As particles for forming an antiglare layer, 6.5 parts by weight of amorphous silica (manufactured by Fuji Silysia chemical Ltd., trade name "SYLOPHOBIC 702") and 6.5 parts by weight of amorphous silica (manufactured by Fuji Silysia chemical Ltd., trade name "SYLOPHOBIC 200") were added, and 2.5 parts by weight of a tackifier (manufactured by Co-op Chemical Co., Ltd., trade name "LUCENTITE SAN") was added to make the thickness after curing treatment 8.0 μm. Except for this, an antiglare film 4 was obtained in the same manner as in Production Example 3. The θa (°) of the antiglare layer of the antiglare film 4 was 2.3. The visible light transmittance of the antiglare film 4 was 91%.

[0385] Production Example 5

[0386] (Preparation of prepolymer)

[0387] 67 parts by weight of butyl acrylate (BA), 14 parts by weight of cyclohexyl acrylate (CHA, manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name "Viscoat#155"), 19 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 0.09 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, trade name "IRGACURE 184"), and 0.09 parts by weight of a photopolymerization initiator (manufactured by BASF Corporation, trade name "IRGACURE 651") were put into a detachable flask equipped with a thermometer, a stirrer, a reflux condenser, and a nitrogen inlet tube, and then nitrogen was introduced, and nitrogen replacement was carried out with stirring for about 1 hour. Then, UVA was irradiated for polymerization to adjust the reaction rate to 5 to 15% to obtain an acrylic prepolymer solution. 2 Irradiate UVA for polymerization to adjust the reaction rate to 5 - 15% to obtain an acrylic prepolymer solution.

[0388] Production Example 6

[0389] (Preparation of polymer RAFT solution A1)

[0390] 50 parts by weight of cyclohexyl acrylate (CHA), 50 parts by weight of 3,3,5-trimethylcyclohexyl acrylate (TMCHA) as monomer components, 0.5 parts by weight of dibenzyl trithiocarbonate (DBTC) as a RAFT agent, 100 parts by weight of ethyl acetate as a polymerization solvent, and 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator were added to a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer, and a stirring device, and solution polymerization was carried out under a nitrogen atmosphere to obtain a polymer RAFT solution A1 with an Mw of 180,000.

[0391] (Preparation of adhesive solution B1 containing an acrylic triblock copolymer)

[0392] Into a reaction vessel equipped with a condenser, a nitrogen inlet tube, a thermometer, and a stirring device, 97 parts by weight of 2-ethylhexyl acrylate (2EHA) as a monomer component, 3 parts by weight of 4-hydroxybutyl acrylate (4HBA), 100 parts by weight of the above-obtained polymer RAFT solution A1, and 100 parts by weight of ethyl acetate as a polymerization solvent were added. 0.2 parts by weight of 2,2'-azobisisobutyronitrile (AIBN) as a thermal polymerization initiator was added, and solution polymerization was carried out under a nitrogen atmosphere to obtain an adhesive solution B1 containing an ABA-type acrylic triblock copolymer with a Mw of 400,000 and a Mw / Mn of 4.3.

[0393] In the calculation of the glass transition temperature (Tg) based on the FOX formula, the Tg of the segment A of the ABA-type acrylic triblock copolymer is 32 °C, and the Tg of the segment B is -70 °C.

[0394] The measurement of the weight-average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of the above product was carried out in the form of standard polystyrene conversion by gel permeation chromatography (GCP method) based on the following measurement conditions.

[0395] · Measuring device: HLC-8320GPC (manufactured by Tosoh Corporation)

[0396] · Chromatographic column: TSKgel GMH-H(S) (manufactured by Tosoh Corporation)

[0397] · Mobile phase solvent: Tetrahydrofuran

[0398] · Flow rate: 1.0 cm 3 / min

[0399] · Column temperature: 40 °C

[0400] Production Example 7

[0401] (Preparation of black adhesive composition)

[0402] To the acrylic prepolymer solution obtained in Production Example 5 (with the total prepolymer being 100 parts by weight), 9 parts by weight of 2-hydroxyethyl acrylate (HEA), 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 0.02 parts by weight of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "KAYARAD DPHA") as a polyfunctional monomer, 0.35 parts by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent, and 0.3 parts by weight of a photoinitiator (manufactured by BASF Corporation, trade name "IRGACURE 651") were added to prepare a photocurable adhesive composition solution.

[0403] To 100 parts by weight of the obtained photocurable adhesive composition solution, 0.2 part by weight of a photoinitiator (manufactured by BASF, trade name "IRGACURE 651") and 4 parts by weight of a black pigment dispersion liquid (manufactured by TOKUSHIKI CO., LTD., trade name "TOKUSHIKI 9050Black") are added to prepare a photocurable black adhesive composition solution.

[0404] Production Example 8

[0405] (Preparation of Black Adhesive Composition)

[0406] In the adhesive solution B1 containing an acrylic triblock copolymer obtained in Production Example 6, 2 parts by weight of a black dye ("VALIFAST BLACK 3810" manufactured by ORIENT CHEMICAL INDUSTRIES CO., LTD.) is added relative to 100 parts by weight of the total amount of monomers used in Production Example 6 to prepare a black solvent-based adhesive composition solution.

[0407] Production Example 9

[0408] (Preparation of Adhesive Composition)

[0409] To the acrylic prepolymer solution obtained in Production Example 5 (with the total prepolymer amount being 100 parts by weight), 9 parts by weight of 2-hydroxyethyl acrylate (HEA), 8 parts by weight of 4-hydroxybutyl acrylate (4-HBA), 0.12 part by weight of dipentaerythritol hexaacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd., trade name "KAYARAD DPHA") as a polyfunctional monomer, and 0.35 part by weight of 3-glycidoxypropyltrimethoxysilane as a silane coupling agent are added to prepare a photocurable adhesive composition solution.

[0410] Production Example 10

[0411] (Preparation of Adhesive Sheet)

[0412] On the release surface of a release film R1 with a thickness of 38 μm (manufactured by Mitsubishi Rayon Co., Ltd., trade name "MRF#38") having a single-sided release surface of a polyester film, the black adhesive composition solution prepared in Production Example 7 is coated so that the cured thickness is 50 μm, and a release film R2 (manufactured by Mitsubishi Rayon Co., Ltd., MRE#38) covering the single-sided release surface of the polyester film is used to block air. From one side of this laminate, using a black light lamp (manufactured by Toshiba Corporation, trade name "FL15BL") with an illuminance of 5 mW / cm 2 and an accumulated light amount of 1300 mJ / cm 2The ultraviolet rays are irradiated under the above conditions. Thus, a pressure-sensitive adhesive sheet 1 with a thickness of 50 μm, which is a cured product of the above black adhesive composition in the form of a substrate-free pressure-sensitive adhesive sheet, is sandwiched between the release films R1 and R2.

[0413] It should be noted that the illuminance value of the above black light is the measured value based on an industrial UV detector (manufactured by TOPCON CORPORATION, trade name: UVR-T1, light-receiving part model UD-T36) with a peak sensitivity wavelength of about 350 nm.

[0414] The visible light transmittance of the pressure-sensitive adhesive sheet 1 is 40%.

[0415] Production Example 11

[0416] (Preparation of pressure-sensitive adhesive sheet)

[0417] Coating is carried out so that the cured thickness is 100 μm, and the rest is the same as in Production Example 10. A pressure-sensitive adhesive sheet 2 with a thickness of 100 μm, which is a cured product of a black adhesive composition in the form of a substrate-free pressure-sensitive adhesive sheet, is sandwiched between the release films R1 and R2.

[0418] The visible light transmittance of the pressure-sensitive adhesive sheet 2 is 16%.

[0419] Production Example 12

[0420] (Preparation of pressure-sensitive adhesive sheet)

[0421] Coating is carried out so that the cured thickness is 150 μm, and the rest is the same as in Production Example 10. A pressure-sensitive adhesive sheet 3 with a thickness of 150 μm, which is a cured product of a black adhesive composition in the form of a substrate-free pressure-sensitive adhesive sheet, is sandwiched between the release films R1 and R2.

[0422] The visible light transmittance of the pressure-sensitive adhesive sheet 3 is 3%.

[0423] Production Example 13

[0424] (Preparation of pressure-sensitive adhesive sheet)

[0425] A polyethylene terephthalate (PET) film with a thickness of 75 μm (manufactured by Mitsubishi Chemical Corporation, "DIAFOIL MRF75") having a silicone-based release layer provided on the surface is used as a substrate. The black solvent-based adhesive composition solution prepared in Production Example 8 is coated on the substrate and dried at 130 °C for 3 minutes to form an adhesive layer with a thickness of 50 μm. A PET film with a thickness of 75 μm (manufactured by Mitsubishi Chemical Corporation, "DIAFOILMRE75") that has been subjected to a silicone release treatment on one side is laminated on the adhesive layer to obtain a pressure-sensitive adhesive sheet 4 with release films attached to both sides in the form of a substrate-free pressure-sensitive adhesive sheet.

[0426] The visible light transmittance of the adhesive sheet 4 is less than 1%.

[0427] Production Example 14

[0428] (Preparation of Adhesive Sheet)

[0429] The black solvent-based adhesive composition solution prepared in Production Example 8 was coated so that the thickness after drying was 75 μm, and the rest was carried out in the same manner as in Production Example 13, to obtain an adhesive sheet 5 with a thickness of 75 μm in which the adhesive layer of the black solvent-based adhesive composition was sandwiched between release films in the form of a non-substrate adhesive sheet.

[0430] The visible light transmittance of the adhesive sheet 5 is less than 1%.

[0431] Production Example 15

[0432] (Preparation of Adhesive Sheet)

[0433] The black solvent-based adhesive composition solution prepared in Production Example 8 was coated so that the thickness after drying was 100 μm, and the rest was carried out in the same manner as in Production Example 13, to obtain an adhesive sheet 6 with a thickness of 100 μm in which the adhesive layer of the black solvent-based adhesive composition was sandwiched between release films in the form of a non-substrate adhesive sheet.

[0434] The visible light transmittance of the adhesive sheet 6 is less than 1%.

[0435] Production Example 16

[0436] (Preparation of Adhesive Sheet)

[0437] The adhesive composition solution prepared in Production Example 9 was coated so that the thickness after curing was 100 μm, and the rest was carried out in the same manner as in Production Example 10, to obtain an adhesive sheet 7 with a thickness of 100 μm in which the photocrosslinkable adhesive as the cured product of the adhesive composition was sandwiched between release films R1 and R2 in the form of a non-substrate adhesive sheet.

[0438] The visible light transmittance of the adhesive sheet 7 is 90%.

[0439] Production Example 17

[0440] (Preparation of Adhesive Sheet)

[0441] The adhesive composition solution prepared in Production Example 9 was coated so that the thickness after curing was 200 μm, and the rest was carried out in the same manner as in Production Example 10, to obtain an adhesive sheet 8 with a thickness of 200 μm in which the photocrosslinkable adhesive as the cured product of the adhesive composition was sandwiched between release films R1 and R2 in the form of a non-substrate adhesive sheet.

[0442] The visible light transmittance of the adhesive sheet 8 is 90%.

[0443] Example 1

[0444] (Preparation of Optical Laminate)

[0445] After pasting the adhesive surface exposed by peeling off the peeling film on one side of the adhesive sheet 8 obtained in Production Example 1 cut into 20 mm × 20 mm at the center of a 45 mm × 50 mm glass plate (visible light transmittance: 93%), the peeling film on the other side was peeled off to expose the adhesive surface. The adhesive surface exposed by peeling off the peeling film on one side of the adhesive sheet 1 obtained in Production Example 1 cut into 20 mm × 20 mm was bonded to the adhesive surface of the adhesive sheet 8, whereby an optical laminate 1 composed of a glass plate / adhesive sheet 8 / adhesive sheet 1 / peeling film was obtained.

[0446] Examples 2 to 6

[0447] (Preparation of Optical Laminate)

[0448] Instead of the adhesive sheet 1, the adhesive sheets 2 to 6 were used, and the same procedure as in Example 1 was carried out, whereby optical laminates 2 to 6 composed of a glass plate / adhesive sheet 8 / adhesive sheets 2 to 6 / peeling film were obtained respectively.

[0449] Comparative Example 1

[0450] (Preparation of Optical Laminate)

[0451] Instead of the adhesive sheet 1, the adhesive sheet 7 was used, and the same procedure as in Example 1 was carried out, whereby an optical laminate 7 composed of a glass plate / adhesive sheet 8 / adhesive sheet 7 / peeling film was obtained.

[0452] (Evaluation)

[0453] The following evaluations were carried out using the optical laminates obtained in the above Examples and Comparative Examples. The evaluation methods are shown below.

[0454] (1) Evaluation of height difference followability

[0455] (Production of uneven adherend)

[0456] After laminating a TAC film (thickness 60 μm) and an adhesive (thickness 20 μm) on a 45 mm × 50 mm glass plate, a CO2 laser (wavelength 10.6 μm, laser diameter 〇 μm) was used to perform linear etching processing on the central 10 mm × 10 mm range at intervals of 150 μm in the length direction and 225 μm in the width direction, whereby an adherend A having a lattice-shaped uneven shape in which the TAC film and the adhesive layer were processed was obtained.

[0457] This adherend A simulates an LED panel on which a plurality of LED chips are arranged on a substrate.

[0458] (Vacuum lamination)

[0459] Using a vacuum lamination device (manufactured by Climb Products, SE340aaH), with an accuracy within the processing range where the adhesive sheet can completely cover the adherend A, the adhesive surfaces exposed by peeling the release films of the optical laminates 1 - 7 prepared in Examples 1 - 6 and Comparative Example 1 were laminated with the processed surfaces of the adherend A, respectively obtaining evaluation samples 1 - 7 composed of glass plate / adhesive sheet 8 / adhesive sheets 1 - 7 / adherend A.

[0460] (Evaluation of height difference followability)

[0461] In evaluation samples 1 - 7, by using the property that when the adhesive sheet successfully follows the concave - convex pattern part, the processed part of the adherend A looks transparent, and the part that fails to follow looks white, the area of the white part was photographed using a fixed - point camera to evaluate the height difference followability.

[0462] Height difference followability (%) = 100 - {[Area of the white part at the time of evaluation] / [Area of the white part before lamination = 1 cm 2 ×100}

[0463] The height difference followability was measured immediately after lamination and at subsequent stages after autoclaving (at 50 °C, 0.5 MPa for 15 minutes, 30 minutes, and 60 minutes). The results are shown in Table 1.

[0464] [Table 1]

[0465] (Table 1)

[0466]

[0467]

[0468] (2) Visible light transmittance

[0469] The optical laminates obtained in the above - mentioned examples and comparative examples were set in a spectrophotometer U4100 (manufactured by Hitachi High - Technologies Corporation) with light incident from the glass plate side, and the transmittance (%) in the visible light region was measured. This transmittance is the Y value measured using a 2 - degree field of view (C light source) of JIS Z 8701 and corrected for luminous efficiency. The results are shown in Table 2.

[0470] (3) Reflectance

[0471] A plate is produced by pasting laminated aluminum foil on a black acrylic plate. The adhesive layer exposed by peeling off the peeling film of the optical laminate obtained in the above-mentioned examples and comparative examples is laminated on the aluminum foil side of the above plate to prepare a sample. The obtained sample is set in a spectrophotometer U4100 (manufactured by Hitachi High-Technologies Corporation) with the anti-glare film / TAC film on the light source side, and the reflectance (%) in the visible light region at 5° regular reflection is measured.

[0472] [Table 2]

[0473] (Table 2)

[0474] Transmittance (550 nm) Reflectance (550 nm) Example 1 40％ 18％ Example 2 16％ 7％ Example 3 3％ 5％ Example 4 <1％ 4％ Example 5 <1％ 4％ Example 6 <1％ 4％ Comparative Example 1 90％ 73％

[0475] Example 7

[0476] (Preparation of optical laminate)

[0477] The adhesive surface exposed by peeling off the peeling film on one side of the adhesive sheet 8 obtained in Production Example 17 cut into 20 mm × 20 mm is pasted on the central portion of the surface of the anti-glare film 1 obtained in Production Example 1 cut into 45 mm × 50 mm where the anti-glare layer is not formed, and then the peeling film on the other side is peeled off to expose the adhesive surface. The adhesive surface exposed by peeling off the peeling film on one side of the adhesive sheet 1 obtained in Production Example 10 cut into 20 mm × 20 mm is bonded to the adhesive surface of the aforementioned adhesive sheet 8, whereby an optical laminate 8 composed of an anti-glare film 1 / adhesive sheet 8 / adhesive sheet 1 / peeling film is obtained.

[0478] Examples 8 to 10

[0479] (Preparation of optical laminate)

[0480] Instead of the anti-glare film 1, the anti-glare films 2 to 4 obtained in Production Examples 2 to 4 are used, and the rest is carried out in the same manner as in Example 7, and optical laminates 9 to 11 composed of anti-glare films 2 to 4 / adhesive sheet 8 / adhesive sheet 1 / peeling film are obtained respectively.

[0481] The following describes various modifications of the present invention.

[0482] [Supplementary Note 1] An optical laminate having a laminated structure in which a first adhesive layer, a second adhesive layer, and a substrate are laminated in sequence,

[0483] The visible light transmittance T1 of the aforementioned first adhesive layer and the visible light transmittance T2 of the aforementioned second adhesive layer satisfy T1 < T2.

[0484] [Supplementary Note 2] The optical laminate according to Supplementary Note 1, wherein the visible light transmittance T1 of the aforementioned first adhesive layer and the visible light transmittance T3 of the aforementioned substrate satisfy T1 < T3.

[0485] [Supplementary Note 3] The optical laminate according to Supplementary Note 1 or 2, wherein the visible light transmittance T1 of the aforementioned first adhesive layer is 80% or less.

[0486] [Supplementary Note 4] The optical laminate according to any one of Supplementary Notes 1 to 3, wherein the visible light transmittance T2 of the aforementioned second adhesive layer is 85 to 100%.

[0487] [Supplementary Note 5] The optical laminate according to any one of Supplementary Notes 1 to 4, wherein the aforementioned first adhesive layer and the aforementioned second adhesive layer are adhesive layers formed from an adhesive composition selected from a photocurable adhesive composition and a solvent-based adhesive composition.

[0488] [Supplementary Note 6] The optical laminate according to Supplementary Note 5, wherein the adhesive composition forming the aforementioned first adhesive layer contains a colorant.

[0489] [Supplementary Note 7] The optical laminate according to Supplementary Note 5 or 6, wherein the aforementioned adhesive composition contains an acrylic polymer.

[0490] [Supplementary Note 8] The optical laminate according to Supplementary Note 7, wherein the aforementioned acrylic polymer contains a (meth)acrylic block copolymer.

[0491] [Supplementary Note 9] The optical laminate according to Supplementary Note 8, wherein the adhesive composition forming the aforementioned first adhesive layer is a solvent-based adhesive composition containing a (meth)acrylic block copolymer.

[0492] [Supplementary Note 10] The optical laminate according to any one of Supplementary Notes 1 to 9, wherein the thickness of the aforementioned first adhesive layer is 10 to 300 μm.

[0493] [Supplementary Note 11] The optical laminate according to any one of Supplementary Notes 1 to 10, wherein the thickness of the aforementioned second adhesive layer is 1 to 500 μm.

[0494] [Supplementary Note 12] The optical laminate according to any one of Supplementary Notes 1 to 11, wherein the ratio of the thickness of the aforementioned second adhesive layer to the thickness of the aforementioned first adhesive layer (thickness of the second adhesive layer / thickness of the first adhesive layer) is 1.0 to 5.0.

[0495] [Supplementary Note 13] The optical laminate according to any one of Supplementary Notes 1 to 12, wherein the surface of the aforementioned substrate on which the aforementioned second adhesive layer is not laminated is subjected to an antireflection treatment and / or an antiglare treatment.

[0496] [Supplementary Note 14] The optical laminate according to Supplementary Note 13, wherein the antiglare treatment is an antiglare layer provided on one side of the substrate.

[0497] [Supplementary Note 15] The optical laminate according to Supplementary Note 14, wherein the antiglare layer is formed using an antiglare layer forming material containing a resin, particles, and a thixotropy imparting agent.

[0498] The antiglare layer aggregates due to the particles and the thixotropy imparting agent, so that an aggregated portion that forms convex portions is present on the surface of the antiglare layer.

[0499] [Supplementary Note 16] The optical laminate according to Supplementary Note 15, wherein, for the convex portions on the surface of the antiglare layer, the average inclination angle θa (°) is in the range of 0.1 to 1.5.

[0500] [Supplementary Note 17] The optical laminate according to any one of Supplementary Notes 1 to 16, further having a surface protection film laminated on the surface layer of the substrate where the second adhesive layer is not laminated.

[0501] [Supplementary Note 18] A self-luminous display device, the self-luminous display device including:

[0502] A display panel in which a plurality of light-emitting elements are arranged on one side of a substrate, and

[0503] The optical laminate according to any one of Supplementary Notes 1 to 17,

[0504] The surface of the display panel on which the light-emitting elements are arranged is laminated with the first adhesive layer of the optical laminate.

[0505] [Supplementary Note 19] The self-luminous display device according to Supplementary Note 18, wherein the display panel is an LED panel in which a plurality of LED chips are arranged on one side of a substrate.

[0506] Industrial applicability

[0507] The optical laminate of the present invention is suitable for encapsulating light-emitting elements of self-luminous display devices such as Mini / Micro LEDs.

Claims

1. An optical laminate having a laminated structure in which a first adhesive layer, a second adhesive layer, and a substrate are laminated in sequence. The visible light transmittance T1 of the first adhesive layer and the visible light transmittance T2 of the second adhesive layer satisfy T1 < T2. The visible light transmittance T1 of the first adhesive layer is 50% or less. The visible light transmittance T2 of the second adhesive layer is 85 - 100%. The surface of the substrate on which the second adhesive layer is not laminated is subjected to an antireflection treatment and / or an antiglare treatment. The ratio of the thickness of the second adhesive layer to the thickness of the first adhesive layer (thickness of the second adhesive layer / thickness of the first adhesive layer) is 1.0 - 5.

0. The visible light transmittance of the optical laminate is 40% or less.

2. The optical laminate according to claim 1, wherein, The visible light transmittance T1 of the first adhesive layer and the visible light transmittance T3 of the substrate satisfy T1 < T3.

3. The optical laminate according to claim 1 or 2, wherein The first adhesive layer and the second adhesive layer are adhesive layers formed from an adhesive composition selected from a photocurable adhesive composition and a solvent-based adhesive composition.

4. The optical laminate according to claim 3, wherein The adhesive composition forming the first adhesive layer contains a colorant.

5. The optical laminate according to claim 3, wherein, The adhesive composition contains an acrylic polymer.

6. The optical laminate according to claim 5, wherein, The acrylic polymer contains a (meth)acrylic block copolymer.

7. The optical laminate according to claim 6, wherein, The adhesive composition forming the first adhesive layer is a solvent-based adhesive composition containing a (meth)acrylic block copolymer.

8. The optical laminate according to claim 1 or 2, wherein, The thickness of the first adhesive layer is 10 - 300 μm.

9. The optical laminate according to claim 1 or 2, wherein, The thickness of the second adhesive layer is 1 - 500 μm.

10. The optical laminate according to claim 1 or 2, wherein The antiglare treatment is an antiglare layer provided on one surface of the substrate.

11. The optical laminate according to claim 10, wherein, The antiglare layer is formed using an antiglare layer forming material containing a resin, particles, and a thixotropy imparting agent. In the antiglare layer, the particles and the thixotropy imparting agent aggregate, so that an aggregated portion forming a convex portion is present on the surface of the antiglare layer.

12. The optical laminate according to claim 11, wherein, In the convex portion on the surface of the antiglare layer, the average inclination angle θa (°) is in the range of 0.1 - 1.

5.

13. The optical laminate according to claim 1 or 2, further comprising a surface protection film laminated on the surface of the substrate on which the second adhesive layer is not laminated.

14. A self-luminous display device, the self-luminous display device comprising: A display panel in which a plurality of light-emitting elements are arranged on one surface of a substrate, and The optical laminate according to any one of claims 1 - 13, The surface of the display panel on which the light-emitting elements are arranged is laminated with the first adhesive layer of the optical laminate.

15. The self-luminous display device according to claim 14, wherein, The display panel is an LED panel in which a plurality of LED chips are arranged on one surface of a substrate.

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