Optical laminate, transparent display including same, and manufacturing method thereof

Abstract

The present invention relates to an optical laminate, a transparent display including same, and a manufacturing method thereof, the optical laminate comprising: a substrate; a metal layer pattern formed on the substrate; a light emitting diode (LED); and a protective layer formed on the metal layer pattern and the light emitting diode, wherein the protective layer is formed of a transparent silicone clear resin composition having a shore A hardness of 35 to 70 on the surface after curing.

Description

Optical laminate, transparent display including same, and method for manufacturing same

[0001] The present invention relates to an optical laminate, a transparent display including the same, and a method for manufacturing the same.

[0002]

[0003] In recent years, technological advancements in the display market have led to a growing demand for large-area display devices. Technological developments are also underway in advanced electronic circuits and display businesses, such as Micro-LEDs and Mini-LEDs, which can individually control brightness per unit area.

[0004] In particular, in the field of transparent displays with multiple light-emitting diodes (LEDs) mounted between the lower and upper plates, multiple glasses have been used as substrates in terms of high transparency, visibility, and durability. However, glass is heavy and can be shattered by environmental factors such as external impacts. In addition, when an individual LED breaks down, it is impossible to individually repair only the defective part, so the entire glass needs to be replaced.

[0005] Recently, transparent LED displays utilizing various organic materials instead of glass are being developed. Korean Patent Publication No. 10-1549265 discloses a composition for encapsulation comprising a polysiloxane acrylate compound having an alkyl group, a cured product, and an organic light-emitting device comprising the same. However, when the compound contains a large number of CC linkages, it is less stable when exposed to heat, light, or chemical substances for a long time, and in particular, yellowness increases, which can pose a problem in ensuring transparency.

[0006]

[0007] The present invention is intended to solve the above-mentioned problems, and provides an optical laminate that does not include a cover glass on one side, so as to be lightweight while protecting internal light-emitting diodes (LEDs) and circuits from external impacts, and that can secure durability and optical reliability from external environmental factors, a transparent display including the same, and a manufacturing method thereof.

[0008] In addition, the present invention aims to provide a transparent display structure and a manufacturing method thereof that can be individually repaired when a light-emitting diode (LED) defect occurs.

[0009]

[0010] The present invention relates to an optical laminate comprising: a substrate; a metal layer pattern formed on the substrate; a light emitting diode (LED); and a protective layer on the metal layer pattern and the light emitting diode, wherein the protective layer is formed of a transparent silicone resin composition having a Shore A hardness of 35 to 70 on the surface after curing.

[0011] In the present invention, in the transparent silicone resin composition, the hydrocarbon group at the terminal in the chemical formula structure may be removed.

[0012] The present invention may be one in which organic impurities contained in the transparent silicone composition are removed.

[0013] The present invention may be characterized in that the transparent silicone resin composition has an organic impurity content of 0.1% or less relative to the total weight of the composition.

[0014] In the present invention, in removing the hydrocarbon group of the transparent silicone resin composition, the terminal hydrocarbon group of a compound included in the transparent silicone resin composition may be replaced with an aryl substituent.

[0015] In the present invention, purification or extraction for removing the transparent silicone resin composition is performed by at least one of plasma cleaning, vacuum distillation, solvent extraction, and high-temperature distillation, and the transparent silicone resin composition may further include at least one selected from among a UV stabilizer, an antioxidant, and a radical inhibitor as a stabilizer.

[0016] The present invention may be such that the yellow index of the optical laminate according to the ASTM E313-73 standard is 1.0 or less, and the b* in the CIE Lab color coordinates of the transmittance color measured using a D65 light source is 1.4 or less.

[0017] The present invention may be characterized in that the viscosity of the transparent silicone resin composition is 1500 to 20000 mPa·s.

[0018] The present invention may be characterized in that the thickness of the protective layer is 40% to 300% of the height of the light-emitting diode (LED).

[0019] In the present invention, the thickness of the metal layer may be 3 µm to 120 µm.

[0020] The present invention may be one in which the metal layer includes at least one selected from the group consisting of tin (Sn), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), silver (Ag), iron (Fe), gold (Au), cobalt (Co), titanium (Ti), and tungsten (W).

[0021] The present invention further includes an adhesive layer formed on one surface of the substrate; and a functional layer provided on a portion of the adhesive layer on which a metal layer pattern is not formed; and may not include a separate member between the metal layer and the adhesive layer.

[0022] In the present invention, the adhesive layer may include a silicone-based adhesive, have a thickness of 5 µm to 50 µm, and have an adhesion strength of 5B or higher with respect to a substrate.

[0023] The present invention may be characterized in that the optical laminate has a transmittance of 90% or more.

[0024] The present invention may be characterized in that the optical laminate may further include a refractive index control layer, and when the optical laminate further includes the refractive index control layer, the transmittance of the optical laminate may be 91% or more.

[0025] In the present invention, the functional layer may include a solder resist layer.

[0026] The present invention also relates to a transparent display including the optical laminate.

[0027] In addition, the present invention relates to a method for manufacturing the optical laminate, comprising the steps of (T1) preparing a metal thin film including a substrate and a silicon-based adhesive layer formed on one surface; (T2) bonding the metal thin film so that the adhesive layer is disposed on one surface of a glass substrate; (T3) patterning the metal layer and developing the metal layer pattern; (T4) etching and removing a portion where the metal layer pattern is not developed; (T5) forming a functional layer on a portion where the metal layer pattern is not formed; (T6) mounting a light-emitting diode (LED); and (T7) forming a protective layer.

[0028] In addition, the step (T7) of forming the protective layer may specifically include a step (P1) of preparing an LED display on which the light-emitting diode (LED) is mounted; a step (P2) of masking the edge of the LED display; a step (P3) of applying a transparent silicone resin composition having a Shore A hardness of 35 to 70 on the surface after curing to form a protective layer on the inside of the masking; and a step (P4) of photocuring the transparent silicone resin composition.

[0029]

[0030] The optical laminate and transparent display according to the present invention include a protective layer formed of transparent silicone resin instead of a cover glass on one side, thereby exhibiting excellent durability against external environmental factors such as yellowing prevention, light resistance, weather resistance, heat resistance, and chemical resistance, and can secure visibility and / or optical reliability.

[0031] In addition, the transparent display has the advantage of being lighter than that of applying multiple cover glasses, and of allowing individual repair of internal light-emitting diodes (LEDs).

[0032]

[0033] FIG. 1 illustrates an optical laminate according to one embodiment of the present invention.

[0034] Figure 2a illustrates an optical laminate (type A) according to Example 2 of the present invention.

[0035] Figure 2b illustrates an optical laminate (type B) according to Example 1 of the present invention.

[0036] Figure 2c illustrates an optical laminate (application of acrylic resin to the protective layer) according to Comparative Example 1.

[0037] Figure 2d illustrates an optical laminate (excluding a protective layer) according to Comparative Example 2.

[0038] FIG. 3 and FIG. 4 are process diagrams showing a method for manufacturing an optical laminate and a transparent display including the same according to one embodiment of the present invention.

[0039] Figure 5 is a process diagram showing in detail the step (T7) of forming a protective layer in the above manufacturing method.

[0040] Figure 6 is a schematic diagram showing a transparent display manufactured according to one embodiment of the present invention.

[0041] Figure 7 is a photograph confirming a state in which LED light bleeding is observed (left) and a state in which LED light bleeding is not observed (right) according to an experimental example of the present invention.

[0042] The symbols in the drawing are as follows:

[0043] 10: Optical laminate

[0044] 100: Protective layer

[0045] 200: Light-emitting diode (LED)

[0046] 300: Metal layer (pattern)

[0047] 400: Substrate

[0048] 500: Adhesive layer

[0049] 600: Functional layer

[0050] 700: Solder layer

[0051]

[0052] The present invention relates to a light-emitting diode (LED) laminate and a transparent display having a protective layer made by curing a transparent silicone resin as a protective layer instead of a cover glass on one side, and a method for manufacturing the same, which enables individual repair of internal light-emitting diodes (LEDs), has excellent durability against external environmental factors such as UV light resistance and weather resistance, and in particular, has the effect of reducing yellowing and improving reliability before and after aging.

[0053] More specifically, the optical laminate of the present invention comprises: a substrate; a metal layer pattern formed on the substrate; a light emitting diode (LED); and a protective layer on the metal layer pattern and the light emitting diode, wherein the protective layer is formed of a transparent silicone resin composition having a Shore A hardness of 35 to 70 on a surface after curing, and the manufacturing method comprises: a step (T1) of preparing a metal thin film including a substrate and a silicone-based adhesive layer formed on one surface; a step (T2) of bonding the metal thin film so that the adhesive layer is disposed on one surface of a glass substrate; a step (T3) of patterning the metal layer and developing the metal layer pattern; a step (T4) of etching and removing a portion where the metal layer pattern is not developed; a step (T5) of forming a functional layer on a portion where the metal layer pattern is not formed; a step (T6) of mounting a light emitting diode (LED); and a step (T7) of forming a protective layer.

[0054]

[0055] Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings. However, the following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the contents of the invention described above, serve to further understand the technical concept of the present invention. Therefore, the present invention should not be interpreted as being limited to the matters described in such drawings.

[0056] The terms used herein are for the purpose of describing embodiments and are not intended to limit the present invention. In this specification, singular forms also include plural forms, unless specifically stated otherwise.

[0057] As used herein, the terms "comprises" and / or "comprising" are used to mean that they do not exclude the presence or addition of one or more other components, steps, operations, and / or elements other than the components, steps, operations, and / or elements mentioned. Like reference numerals refer to like elements throughout the specification.

[0058] Spatially relative terms such as “below,” “bottom,” “lower,” “above,” “top,” and “upper” can be used to easily describe the relationship between one element or component and other elements or components, as depicted in the drawings. Spatially relative terms should be understood to include different orientations of the elements during use or operation in addition to the orientation depicted in the drawings. For example, if an element depicted in a drawing is flipped over, an element described as “below” or “lower” of another element may end up “above” the other element. Thus, the exemplary term “below” can include both the above and below directions. Elements can also be oriented in other directions, and thus spatially relative terms can be interpreted based on their orientation.

[0059]

[0060] Optical laminates and transparent displays

[0061] FIG. 1 illustrates an optical laminate according to an embodiment of the present invention, and FIGS. 2A and 2B are diagrams showing in detail an optical laminate and a transparent display according to one or more embodiments of the present invention, according to implementation examples. Referring to FIG. 1, the optical laminate (10) of the present invention may include a substrate (400), a metal layer pattern (300), a light emitting diode (LED) (200), and a protective layer (100). In addition, referring to FIGS. 2A and 2B, the optical laminate (10) may further include an adhesive layer (500), a functional layer (600), and / or a solder layer (700). In particular, the present invention is characterized in that it exhibits an effect of utilizing the viscoelastic properties, which are advantages of silicone, while reducing stickiness by applying a transparent silicone resin having a surface Shore A hardness of 35 to 70 to the protective layer (100). Specifically, it is advantageous in durability, such as external shock absorption, due to fluidity for elasticity within the above-mentioned Shore A hardness range, while also securing the effect of maintaining the appearance of a solid that is strong against momentary impact.

[0062]

[0063] The above substrate (400) is not particularly limited as long as it is generally transparent and does not impair the optical properties of the optical laminate, and examples thereof include glass, ceramics, etc. that ensure flatness and have a transmittance of 89% or more, but it is most preferable to use glass.

[0064] The above glass may include, for example, oxide glass such as silicate glass, borate glass, phosphate glass, etc. In this case, there is an advantage in that heat shrinkage phenomenon, etc. does not occur in subsequent processes, etc., and a predetermined hardness can be imparted to the optical laminate. The type of glass substrate may be quartz, borosilicate, aluminosilicate, alkali-free, soda lime GLASS, etc., and its application range is not limited thereto. In this case, the shape is not limited to a specific shape such as a wafer shape or a square flat plate, and can be processed and used in various ways depending on the purpose.

[0065] In one or more embodiments, the substrate (400) may have a thickness of 0.5 mm to 20 mm. When the thickness of the substrate (400) satisfies the above range, the substrate (400) can be thinned while having excellent hardness, and can prevent deformation or cracking of the metal layer (300). Specifically, when it is less than 0.5 mm, it may be difficult to protect the metal layer (300) or other laminated members from external impact, and when it exceeds 20 mm, it may be disadvantageous in terms of thinning or weight reduction. In addition, when used in a place where strength is required, it can be used according to the purpose in a thickness range of 3 mm to 20 mm. Tempered glass can also be utilized, and in the case of thin glass in the range of 0.5 mm to 20 mm, it is preferable to use chemically strengthened tempered glass for quality. In addition, both heat strengthening and chemically strengthening can be used in a thickness of 3 mm to 20 mm or more.

[0066] In one or more embodiments, the substrate (400) may have a single-layer or multi-layer structure. For example, the substrate (400) may have a single-layer structure formed of a single glass substrate, but is not necessarily limited thereto, and may also have a multi-layer structure in which a plurality of glass substrates are laminated.

[0067]

[0068] The above substrate may include a metal layer and / or a metal layer pattern (300). The metal layer (300) may be used as an electrode and / or wiring in an electronic device such as a display device including the optical laminate. Specifically, the 'wiring' may be composed of data and power wiring, a land portion to which a light emitting diode (LED) is attached, and a pad portion attached to an FPCB (Flexible Printed Circuit Board) for driving and power supply, and may be used to electrically connect each of a plurality of light emitting diodes (LED).

[0069] The above metal layer (300) is not particularly limited as long as it has electrical conductivity, and may include, for example, one or more selected from the group consisting of tin (Sn), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), silver (Ag), iron (Fe), gold (Au), cobalt (Co), titanium (Ti), and tungsten (W). Preferably, copper foil is used in terms of processability, ease of acquisition, conductivity, etc.

[0070] The metal layer (300) may be formed by a known metal thin film process, for example, by preparing and attaching a metal thin film, or by using at least one method selected from the group consisting of electroless deposition, electroplating, sputtering, thermal evaporation, and electron beam evaporation, but is not limited thereto. According to one embodiment of the present invention, the metal layer (300) is formed by a copper foil photo / etching process, and tin plating is performed on the upper portion of the copper foil to provide the visual characteristics of copper and the adhesive force for soldering a light emitting diode (LED).

[0071] The metal layer (300) may have a thickness of 3 µm to 120 µm, preferably 3 µm to 110 µm, and more preferably 18 µm to 105 µm. If the thickness of the metal layer (300) is less than the above range, it may not be easy to form a uniform thin film or pattern, and if it exceeds the above range, there may be a problem in that it cannot be applied to an electronic device having a thin film structure.

[0072]

[0073] According to FIGS. 2a and 2b, the metal layer (300) may further include an adhesive layer (500) in consideration of attachment to the substrate (400).

[0074] The adhesive layer (500) should have excellent adhesion between the substrate (400) and the metal layer (300) and ensure transparency. In one embodiment of the present invention, it is preferably manufactured from an adhesive layer composition including a silicone-based adhesive. The adhesive layer composition of the present invention includes a silicone-based additive and a solvent, and may further include an additive. Specifically, in the case of including an adhesive layer formed using a conventional acrylic-based adhesive or an epoxy-based adhesive, there was a problem that the adhesion to the glass substrate was insufficient, or the adhesive layer was damaged by the etchant used for etching the metal layer formed on the upper portion of the adhesive layer. Furthermore, in the case of being used in a product mainly used outdoors, such as a transparent display, there was a problem that the adhesion of the adhesive layer to the glass substrate was reduced, or yellowing of the adhesive layer occurred, which caused product defects. In order to solve this problem, the inventor of the present invention has derived the present invention by noting that when the adhesive layer (500) includes a silicone-based adhesive, not only is the adhesive strength with the glass substrate excellent, but also the chemical resistance to the etchant is excellent, and the heat resistance and reliability in high temperature and high humidity environments are excellent.

[0075] The silicone-based adhesive may be at least one of a silicone compound and a siloxane compound. The silicone compound may be used without particular limitation as long as it is a compound containing a silicon (Si) atom. In addition, the siloxane compound may be a compound containing a siloxane bond of a Si-O bond without limitation. More specifically, in one example of the present invention, the silicone compound and the siloxane compound may be at least one of trimethylated silica, vinyl terminated polydimethylsiloxane, hexamethyl di siloxane, trisiloxane, and tetrakis(trimethylsilyloxy)silane.

[0076] In particular, it is preferable that the silicone-based adhesive of the present invention be included in an amount of 40% to 60% based on the total weight of the adhesive layer composition. In this way, the silicone-based adhesive of the present invention can be added by being diluted at a lower concentration than conventional adhesives, and thus, when bonding the adhesive layer of the present invention to a metal layer or substrate, the adhesion to the metal layer or substrate can be maximized, so that bonding is possible without additional treatment such as UV curing of the adhesive layer, which has the advantage of being possible.

[0077] The solvent is not particularly limited as long as it can dilute the silicone-based adhesive, but may be, for example, toluene, xylene, PGME, and / or PGMEA. It is preferable that the solvent of the present invention be included in an amount of 40% to 55% of the total weight of the adhesive layer composition, from the perspective of stability of the adhesive coating thickness under the metal layer.

[0078] The above additive may be one or more of an anchorage, a cross linker, and a catalyst.

[0079] The above anchorage is added to increase the bonding strength with the metal layer during adhesive layer coating, thereby preventing the adhesive layer from being separated from the metal layer. Generally, there are no particular limitations on the material used as the anchorage, but it is preferable that it does not undergo thermal deformation at temperatures below 200°C.

[0080] The above crosslinking agent is a substance added for chemical bonding between components of the adhesive layer composition, and is preferably a product that does not undergo thermal deformation at 200°C or lower.

[0081] The above catalyst is a component added for curing the adhesive layer composition, and helps the adhesive layer composition transform from a liquid phase to a solid phase. Specific examples include a platinum catalyst, a palladium catalyst, and / or an osmium catalyst.

[0082] It is preferable from the viewpoint of adhesive stability that the additive of the present invention is included in an amount of 0.1% to 10% based on the total weight of the adhesive layer composition.

[0083] The adhesive layer (500) of the present invention may be formed by heating the adhesive layer composition to a temperature of 100°C to 180°C and curing it.

[0084] The adhesive layer (500) may have a thickness of 5 µm to 50 µm, preferably 5 µm to 30 µm, and preferably 5 µm to 25 µm. If the thickness of the adhesive layer (500) is less than 5 µm, sufficient adhesive strength with other members cannot be maintained, and if it exceeds 50 µm, there may be a disadvantage in terms of increasing the thickness of the product.

[0085] In one embodiment, the adhesive layer (500) may not include a separate member, for example, an intermediate layer or a protective layer, at the contact interface with the metal layer (300). Specifically, in the case of an adhesive layer formed using a conventional acrylic adhesive or an epoxy adhesive, as described above, there was a problem in that the adhesive layer was damaged by the etchant used to etch the metal layer formed on the upper portion of the adhesive layer, for example, in the case of an adhesive layer formed using an epoxy adhesive, the opacity of the adhesive layer increased when in contact with the etchant. Therefore, in order to prevent damage to the adhesive layer due to the etchant, the conventional optical laminate separately included a member of an intermediate layer or a protective layer between the adhesive layer and the metal layer. However, when a separate member is included in this way, not only was the processability lowered and the manufacturing cost increased due to the addition of a manufacturing process, but there was also a problem in that it was disadvantageous in terms of producing a thin film. However, the present invention forms an adhesive layer using a silicone-based adhesive having excellent chemical resistance to an etchant as described above, so that damage to the adhesive due to the etchant does not occur, and thus a separate intermediate layer or protective layer that was previously provided for protecting the adhesive is not included, thereby not only improving processability but also providing an advantage in terms of reducing manufacturing costs, and further providing an advantage in terms of thinning the film.

[0086] In one embodiment, the adhesive layer (500) may have an adhesion strength of 5B or greater with respect to the substrate (400). As described above, the adhesive layer (500) includes a silicone-based adhesive, and thus is characterized by excellent adhesion strength with respect to the substrate (400).

[0087] In one embodiment, the adhesion of the adhesive layer (500) to the substrate (400) may be evaluated by the measurement standard ISO 2409: Standard Test Methods for Measuring Adhesion by Tape Test.

[0088]

[0089] The functional layer (600) is formed on the adhesive layer (500) where the metal layer (300) pattern is not formed, that is, on the adhesive layer (500) exposed by etching the metal layer when the metal layer (300) pattern is formed. The functional layer (600) may be formed to protect the wiring and the exposed substrate by filling the portion where the metal layer (300) pattern is not formed, as shown in FIGS. 2A and 2B , and more specifically, may be formed in a form that is connected to the portion where the metal layer (300) is not formed on the adhesive layer (500) and laminated on the metal layer (300). The organic film may include PMMA, acrylic, urethane, and / or epoxy, and a silicon-based protective film may be used depending on optional specifications, but is not limited thereto.

[0090] More specifically, the functional layer (600) may be formed to cover all or part of the metal layer (300) pattern. In one embodiment of the present invention, when there are multiple metal layer patterns, the functional layer may be formed to cover all or part of each metal layer pattern. More preferably, as shown in FIGS. 2a and 2b, the functional layer (600) is formed to cover all of some metal layer patterns (left and right metal layers among the four metal layer patterns of FIGS. 2a and 2b), and some metal layer patterns are formed to cover only part of some of the metal layer patterns (the middle two metal layers among the four metal layer patterns of FIGS. 2a and 2b). In this case, the metal layer pattern on which the functional pattern is only partially covered may be for mounting a light emitting diode (LED) (200). In addition, the metal layer pattern on which the functional pattern is completely covered may function as a wiring. In this way, when the functional layer is formed to cover only a portion of the metal layer pattern, the degree to which the functional layer is formed on the metal layer pattern is not particularly limited as long as it is suitable for mounting a light-emitting diode (LED) (200), but the number of contact pins may be spaced apart at a certain distance, including signal lines and power lines, such as 4 pins and 5 pins, according to the type and size of the LED and the display pixel pitch in proportion to the contact area for LED mounting, to form a pattern.

[0091] Meanwhile, as described above, a metal layer (300) is laminated on one surface of the adhesive layer (500) of the present invention, and the metal layer (300) may have a surface roughness (Rz) of 0.1 to 20 ㎛.

[0092] At this time, since the adhesive layer (500) includes a silicone-based adhesive layer, the surface shape of the metal layer (300) is directly reflected in the adhesive layer (500). Therefore, when the metal layer (300) is patterned and then peeled off, the surface of the adhesive layer (500) exposed by the etching of the metal layer has irregularities derived from the metal layer having a certain surface roughness, which causes light scattering and increases haze when applied to a transparent display. Therefore, by providing a functional layer (600) in a portion of the metal layer (300) of the adhesive layer (500) where the pattern is not formed so that the surface irregularities of the adhesive layer (500) do not appear, diffuse reflection can be prevented, haze can be reduced, and visibility can be improved. In this respect, the functional layer (600) may have a surface roughness (Rz) of 5.0 μm or less. If the above surface roughness (Rz) exceeds 5.0㎛, diffuse reflection occurs, haze increases, and there is a problem of being recognized as cloudy.

[0093] The functional layer (600) may include a solder resist layer. More specifically, the functional layer (600) may be formed by a solder resist. The solder resist may be formed by any one of thermal curing, photocuring, and thermal / photocuring, and may be either a liquid type or a film type. When the solder resist is a liquid type, it may be manufactured from a solder resist composition including a binder resin, a photopolymerizable compound, a photopolymerization initiator, a pigment, a dye, a solvent, and / or other additives. When the solder resist is a liquid type, since the printing and drying processes must be repeated during manufacturing, it is more preferable to apply a film type described below in the present invention. When the solder resist is a film type, it may include a protective film, a photosensitive resin layer, and a base film. The base film includes a polyester film such as polyethylene terephthalate and is used as a support. The above protective film serves as a protective layer that prevents damage to the resist, but is not limited thereto. The photosensitive resin layer may use the same components as the liquid type solder resist composition. In addition, when the solder resist is a film type, it is preferable in that air bubbles are unlikely to be mixed between the substrate and the solder resist layer, the film has excellent flatness, allowing for efficient mounting of light-emitting diodes (LEDs), and having high resolution.

[0094] The functional layer can be patterned using photolithography to partially cover the metal layer pattern. Accordingly, a light-emitting diode (LED) can be applied onto the metal layer pattern in a form suitable for mounting. The specific method of photolithography is not particularly limited, but the method described in the following description of the method for manufacturing an optical laminate can be applied without limitation.

[0095] Among the above functional layers (600), the thickness laminated on the metal layer (300) may be 1 µm to 3 mm.

[0096]

[0097] In addition, a solder layer (700) may be further included in a portion of the patterned metal layer (300) where the functional layer (600) is not formed, and a light-emitting diode (LED) (200) to be described later may be mounted on this portion. The solder layer (700) must have excellent mechanical properties and electrical conductivity, and any composition, type, method, etc. commonly used in the field may be used without limitation. In one embodiment of the present invention, by applying a cream-like lead (Pb) solder cream and then applying it only to a portion where the functional layer (600) is not formed using a squeezer, the occurrence of a short circuit can be prevented, thereby reducing defects.

[0098]

[0099] The above light emitting diode (LED) (200) is a light emitting element that is mounted on a substrate by using the SMT (Surface Mount Technology) method in the portion where the solder layer (700) is formed and emits light when voltage is applied. Each LED may be a light emitting diode (LED) that emits red light, green light, blue light, etc., and a combination of these may implement light of various colors including white. The plurality of light emitting diodes (LED) (200) include an N-type electrode and a P-type electrode and may be formed in various structures such as a lateral type, a vertical type, a flip chip type, etc. In one embodiment of the present invention, the light emitting diode (LED) (200) may be any known light emitting diode (LED) without limitation, and the implementation examples thereof are not limited thereto. However, it is preferable in terms of practicality to use a type in which RGB and a driver IC are packaged.

[0100] The arrangement spacing or density of the above light emitting diodes (LEDs) (200) is not particularly limited, but may be arranged in a grid pattern. In this case, the upper, lower, left, and right spacings may be 1 to 50 mm, and the spacings of a plurality of light emitting diodes (LEDs) may be the same or different from each other. When light emitting diodes (LEDs) are formed on the metal thin film substrate of the present invention, there is an advantage as a transparent display capable of transmitting and reproducing images on a substrate having transparency.

[0101]

[0102] The above protective layer (100) is formed on a substrate on which a light-emitting diode (LED) (200) is mounted. According to one embodiment of the present invention, the protective layer is characterized by being formed of a transparent silicone resin composition having a Shore A hardness of 35 to 70 on the surface after curing. The hardness test was performed using a Digital Durometer hardness tester (Shore A), and the indentor is Zwick 3130 (Shore A) (manufactured by Zwick Roell), and follows the test standard ISO 7619-1, ASTM D. The composition has an advantage in terms of viscoelasticity because the Shore A hardness of the surface after curing satisfies 35 to 70, preferably 40 to 70. Specifically, the elasticity is similar to the rubber properties of a rubber eraser or a tire tread, but due to the nature of silicone, it also has the characteristic of maintaining its shape when a strong external impact occurs, so it can implement a transparent display while satisfying the function of protecting a transparent LED display. In the present invention, the surface is not particularly limited as long as it is a surface recognizable to a person skilled in the art when measuring the hardness of the silicone resin, but may be 22 or less based on the Shore D hardness standard, and all hardness expression methods of rubber, elastomer, and plastic products can be used, and can be expressed using a durometer, etc.

[0103] The transparent silicone resin composition used in the above protective layer may have a yellow index of about 0.2 according to the ASTM E313-73 standard and b* of about 0.2 in the CIE Lab color coordinates of the transmittance color measured using a D65 light source.

[0104] In a transparent display, the substrate must internally have stability against the heat generated by the LED light and block internal organic leaching substances such as the LED package, solder paste, and copper foil adhesive, and externally ensure durability against heat, moisture, and / or sunlight. The protective layer (100) in the present invention is introduced for the purpose of high reliability by replacing the existing glass substrate or transparent acrylic substrate, and the transparent silicone resin composition used in the protective layer of the present invention is characterized by a repeating Si-O siloxane structure. Si-O has a higher bonding energy than CC, ensures heat, light, and / or chemical stability, and has a hydrophobic property, so it has low moisture absorption, etc. In addition, it has the advantage of being resistant to low-temperature shrinkage and expansion and low-temperature brittle fracture, and thus has superior stability at low temperatures compared to other materials containing many CC bonds such as epoxy, acrylic, polyurethane butadiene rubber. In particular, it has the advantage of maintaining transparency and reliability for a long time because the yellowing is low even after long-term exposure to UV. The transparent silicone resin composition of the above protective layer (100) may specifically not contain a CC bond.

[0105]

[0106] The transparent silicone resin composition of the present invention may have hydrocarbon groups removed and may have other organic impurities removed.

[0107] In one embodiment of the present invention, the transparent silicone resin composition may be one in which a hydrocarbon group at the end of the chemical formula of the transparent silicone resin composition, specifically a methyl group, is replaced with an aryl group having higher UV stability to remove the hydrocarbon group. The hydrocarbon group may react with oxygen to produce an oxidation byproduct when exposed to high-intensity UV for a long time, which may cause discoloration, and may form free radicals when decomposed by UV, and may react with other methyl groups or siloxanes in the silicone resin to cause structural changes and accelerate yellowing. In addition, the hydrocarbon group, specifically the methyl group, has low UV absorption but can absorb a small amount of UV energy in the entire structure having a Si-O skeleton, which may cause slight damage to the methyl group and the siloxane skeleton, which may cause discoloration when exposed to an external environment such as UV for a long time. Therefore, by removing hydrocarbon groups through a hydrosilylation reaction including a platinum catalyst, etc., the change in the stability state can be reduced even after aging, and thus transparency (chromaticity) that does not discolor even under external environmental factors such as outdoor installation environments can be implemented.

[0108] The above organic impurities are a concept including impurities included in the transparent silicone resin composition, other than the hydrocarbon group at the end of the chemical formula described above, and are separate organic substances in the composition. Since these organic impurities may cause yellowing when continuously exposed to light, resulting in a decrease in transmittance, in one embodiment of the present invention, the transparent silicone resin composition may have these organic impurities removed through a separate treatment such as purification and / or extraction. The purification of the transparent silicone resin composition to remove organic impurities may be performed through a general purification method such as distillation or filtration, and the extraction to remove the organic impurities may apply a vacuum distillation and / or solvent extraction method to remove volatile organic impurities. Specifically, the removal of organic impurities may be treated by one or more selected methods such as plasma cleaning, vacuum distillation, solvent extraction, and / or high-temperature distillation, but is not limited thereto.

[0109] For example, when organic impurities are removed by the high-temperature distillation method, some low-molecular-weight silanes and hydrocarbons, which are low-boiling-point impurities, can be removed in the range of 100 to 150°C, organic substances added during the process such as methane, ethanol, and acetone, and medium-boiling-point impurities such as organic solvents and dichloromethanes, which are organic solvents, can be removed in the range of 150 to 200°C, and then some high-molecular-weight silanes and cyclic compounds such as benzene and naphthalene, which are high-boiling-point impurities, can be removed in the range of 200 to 250°C.

[0110]

[0111] In addition, in one embodiment of the present invention, the transparent silicone resin composition may further include known additives such as a catalyst or stabilizer, and the viscosity of the composition may be characterized as being 1500 to 20000 mPa·s.

[0112] In addition, the catalyst is a component added for curing a transparent silicone resin composition, and helps the transparent silicone resin composition transform from a liquid phase to a solid phase. Specific examples thereof include a platinum catalyst, a palladium catalyst, and / or an osmium catalyst.

[0113] The above stabilizer may further include at least one selected from a UV stabilizer, an antioxidant, and a radical inhibitor. Examples thereof include specific lactone-based antioxidants such as phenol-based antioxidants, amine-based antioxidants, and benzofuranone. If a stabilizer is further included, it has the effect of suppressing residual radicals that may be generated during photocuring.

[0114] The above additive may be one or more of an anchorage, a cross linker, and a catalyst.

[0115] The above anchorage is added to increase the bonding strength with the laminate during the protective layer coating process, thereby preventing the protective layer from detaching. Generally, there are no particular limitations on the material used as the anchorage, but it is preferable that it does not undergo thermal deformation at temperatures below 200°C.

[0116] The above crosslinking agent is a substance added for chemical bonding between the components of the transparent silicone resin composition, and is preferably a product that does not undergo thermal deformation at 200°C or lower.

[0117] From the viewpoint of stability, it is preferable that the additive of the present invention be included in an amount of 0.1% to 10% based on the total weight of the transparent silicone resin composition.

[0118] The thickness of the protective layer may be characterized by being 40% to 300%, preferably 40% to 250%, and more preferably 42.86% to 214.29% of the height of the light emitting diode (LED). According to Fig. 2a (Type A), the protective layer (100) is formed higher than the height of the light emitting diode (LED) to protect the entire substrate and the light emitting diode (LED). In this case, when a defect occurs in some light emitting diodes (LED), individual light emitting diodes (LED) can be repaired by cutting the protective layer of the corresponding area, repairing it, and then applying and curing an additional silicone resin composition. In addition, as in the form of Fig. 2b (Type B), the light emitting diode (LED) can be formed to be partially exposed to protect the wiring and the lower part of the LED. In this case, individual light emitting diodes (LED) can be repaired without removing the protective layer. Type B has the additional advantage of having less light scattering than Type A, especially since there is no reflective medium for the light emitting diode (LED). If the height of the protective layer exceeds the above range, there may be problems with curing properties, transparency, etc., and the increased manufacturing cost due to the increased thickness may also be a problem. In addition, if it is lower than the above height, there is a possibility that it may not sufficiently protect the substrate, and if it becomes lower than the height of the solder layer applied when mounting the light emitting diode (LED) or the thickness of the wiring, it cannot function as a protective layer.

[0119] According to an embodiment of the present invention, a transparent silicone resin composition can achieve the effect of preventing yellowing and improving optical performance such as transmittance of an optical laminate by removing hydrocarbon groups and / or organic impurities as described above and specifically controlling the content of organic impurities to 0.1% or less based on the total weight of the composition. As a method for measuring the content of organic impurities, a qualitative analysis using ATR-FTIR can be performed to confirm the presence of a target substance, and then a calibration curve can be created using GC MS (gas chromatography mass spectrometry) and quantitative analysis can be performed to measure the content, but the present invention is not limited thereto.

[0120]

[0121] The optical laminate according to the present invention has a yellow index (Yellow Index) of 1.0 or less according to the ASTM E313-73 standard, and preferably, the change after UV exposure may be 0.01 or less, and the b* in the CIE Lab color coordinate of the transmittance color measured using a D65 light source may be 1.4 or less, and preferably, the change after UV exposure may be 0.01 or less. In addition, the optical laminate of the present invention may have a transmittance of 90% or more. By reducing the yellow index, there is an effect of improving clarity and reducing haze by preventing absorption of visible light and / or scattering of light.

[0122] In addition, the optical laminate according to the present invention may further include a refractive index adjusting layer as an optical treatment capable of adjusting the reflectivity of the surface, and in this case, the transmittance may be further improved to 91% or more.

[0123]

[0124] <Method for manufacturing optical laminates>

[0125] FIGS. 3 and 4 are process diagrams illustrating a method for manufacturing an optical laminate according to an embodiment of the present invention. The method for manufacturing an optical laminate according to an embodiment of the present invention may include a step (T1) of preparing a metal thin film including a substrate and a silicon-based adhesive layer formed on one surface; a step (T2) of bonding the metal thin film so that the adhesive layer is disposed on one surface of a glass substrate; a step (T3) of patterning the metal layer and developing the metal layer pattern; a step (T4) of etching and removing a portion where the metal layer pattern is not developed; a step (T5) of forming a functional layer on a portion where the metal layer pattern is not formed; a step (T6) of mounting a light-emitting diode (LED); and a step (T7) of forming a protective layer.

[0126] Specifically, the step (T1) of preparing a metal thin film including a substrate and a silicon-based adhesive layer formed on one side thereof can be applied as is to the contents of the substrate (400), adhesive layer (500), and metal layer (300) described above, and therefore description thereof will be omitted.

[0127] In the step (T2) of bonding the thin film so that an adhesive layer is disposed on one surface of the glass substrate, the step can be appropriately performed within a range that does not harm the purpose of the present invention, and bonding can be performed using, for example, a laminator or the like.

[0128] The step (T3) of patterning the metal layer and developing the metal layer pattern may include a step of applying a photoresist pattern forming composition onto the metal layer (300) by spin coating, slit coating, inkjet printing, etc., a step of drying and heat treating the applied photoresist pattern forming composition to form a photoresist film, and a step of selectively exposing and developing the photoresist film to dissolve and remove the photoresist film corresponding to the exposed area or the non-exposed area, thereby forming a photoresist pattern. The step of forming the photoresist pattern may be performed by a known method, and details are omitted.

[0129] The step (T4) of etching and removing the portion of the above metal layer pattern that is not developed is not particularly limited and may be performed by a dry etching process or a wet etching process. The dry etching process or the wet etching process may be performed by a known method. In one embodiment, the etching process may have excellent etching performance for the metal layer (300) when performed by dry etching, but is not limited thereto.

[0130] The step (T5) of forming a functional layer in a portion where the metal layer pattern is not formed may be a step of forming a solder resist layer of either a liquid type or a film type, and preferably, may be a step of forming a solder resist layer. The method of forming the functional layer (600) is not particularly limited, but may be a method of manufacturing a solder resist layer of either the liquid type or the film type using a known method.

[0131] The step (T6) of mounting the above light emitting diodes (LEDs) is not particularly limited, and first, a solder layer (700) is applied to bond the light emitting diodes (LEDs), and each light emitting diode (LED) is arranged in the corresponding portion to align a plurality of light emitting diodes (LEDs). In the present invention, the method by which the light emitting diodes (LEDs) are formed in the optical laminate of the present invention may use a method of surface mounting (SMT: Surface Mount Technology) of the element by soldering, but is not limited thereto. Various high-resolution transparent displays can be implemented depending on the alignment interval, area, etc. of the light emitting diodes (LEDs). The arrangement interval or density of the light emitting diodes (LEDs) is not particularly limited, but may be arranged in a grid shape. In this case, the upper, lower, left, and right intervals may be 1 to 50 mm, and the intervals of the plurality of light emitting diodes (LEDs) may be the same or different from each other. When a light emitting diode (LED) is formed on the metal thin film substrate of the present invention, there is an advantage as a transparent display capable of transmitting and reproducing images on a substrate having transparency.

[0132] According to the process diagram of FIG. 5 and one embodiment, the step (T7) of forming the protective layer may specifically include a step (P1) of preparing an LED display on which the light-emitting diode (LED) is mounted; a step (P2) of masking the edge of the LED display; a step (P3) of applying a transparent silicone resin composition having a Shore A hardness of 35 to 70 on the surface after curing to form a protective layer on the inside of the masking; and a step (P4) of photocuring the transparent silicone resin composition. The tape used in the masking step may be a known damming tape that is slit as needed. In addition, since the contents of the protective layer and the transparent silicone resin composition for forming the protective layer can be applied as is to the contents of the above-described protective layer (100), description thereof will be omitted. The above transparent silicone resin composition may be a heat-curable or photo-curable composition, but according to one embodiment of the present invention, it has a heat-curable or photo-curable composition of 4000 to 8000 mJ / cm based on 365 nm. 2 It is desirable to cure under UV light conditions.

[0133]

[0134] Transparent Display and Manufacturing Method

[0135] The present invention includes a transparent display manufactured using the optical laminate of the present invention described above and a manufacturing method thereof.

[0136] Specifically, the present invention relates to the optical laminate (10) described above; and a transparent display including the same. Fig. 6 is a diagram briefly illustrating an embodiment of the transparent display of the present invention. Referring to Fig. 6, the transparent display of the present invention is based on including a plurality of light-emitting diodes (LEDs) uniformly arranged on a substrate (100), and a protective layer (100) formed on the upper surface with a transparent silicone resin composition.

[0137]

[0138] The optical laminate of the present invention, by exhibiting the above-described characteristics, can be suitably used in display devices requiring large areas and low resistance, and in particular, has the characteristic of being suitably used in devices that can be exposed to the external environment for long periods of time, such as transparent displays, in terms of excellent light resistance, heat resistance, and reliability in high temperature and high humidity environments. In particular, it has the advantage of enabling repair of individual light-emitting diodes (LEDs).

[0139]

[0140] Hereinafter, experimental examples including specific examples and comparative examples are presented to help understand the present invention, but these are only illustrative of the present invention and do not limit the scope of the appended claims. It will be apparent to those skilled in the art that various changes and modifications to the examples are possible within the scope and technical idea of ​​the present invention, and it is natural that such changes and modifications fall within the scope of the appended claims. “%” and “parts” in the examples mean “mass%” and “mass parts”, respectively, unless otherwise specified.

[0141]

[0142] Manufacturing Example 1: Manufacturing of transparent silicone resin composition A

[0143] A transparent silicone resin composition A was prepared by mixing hydride-terminated polydimethylsiloxane, vinyl-terminated polydimethylsiloxane, and a platinum catalyst to have the following properties. The properties of the transparent silicone resin composition A prepared according to Manufacturing Example 1 are as follows.

[0144] - Viscosity: 4000~20000 mPa·s

[0145] - Shore A hardness after curing: 40~70 (Durometer hardness)

[0146] - Refractive index: 1.40~1.41, haze value less than 1%

[0147] - Curing shrinkage: less than 0.2 Vol%

[0148]

[0149] Manufacturing Example 2: Manufacturing of transparent silicone resin composition B

[0150] A high-temperature (heating) distillation method that uses temperature to separate organic impurities was applied to a composition of Hydride Polydimethylsiloxane and Vinyl Polydimethylsiloxane that did not undergo a hydrocarbon group removal process, to purify / distill organic impurities. The distillation method is as follows: the temperature is increased from room temperature to 100°C at a rate of 4°C per minute, standby for 30 minutes, then increased to 150 to 200°C, maintained at 200°C for 1 hour to distill organic impurities, then increased to 250°C and maintained for 1 hour, then heating was stopped and the composition was cooled. 1.5 parts by weight of a peroxide-based photocuring initiator was added and stirred to prepare a transparent silicone resin composition B. The physical properties of the transparent silicone resin composition B prepared according to Manufacturing Example 2 are as follows.

[0151] - Viscosity: 4000~20000 mPa·s

[0152] - Shore A hardness after curing: 35~50 (Durometer hardness)

[0153] - Refractive index: 1.40, haze value less than 1%

[0154] - Curing shrinkage: less than 4 Vol%

[0155]

[0156] Examples 1 to 2: Fabrication of optical laminates

[0157] A 1.8 mm glass substrate was prepared, and an adhesive layer composition (DOWSIL™ 96-083 Silicone Adhesive Kit, DOW; containing 70% solid content) was applied on one side of a 50 ㎛ thick copper metal substrate by the gravure coating method, and then cured at 150°C for 2 minutes to manufacture a metal thin film in which a 10 ㎛ thick silicone adhesive layer was formed on one side of the metal substrate.

[0158] After arranging the adhesive layer of the metal thin film on one side of the glass substrate so that it is in contact with it, the metal thin film is bonded by a sheet-to-sheet method to laminate a metal layer, and the metal layer is patterned by a photolithography method to develop the metal layer pattern, and the undeveloped portion is etched and removed to form a metal layer pattern. The metal layer pattern includes DATA and power wiring, a Land portion where an LED is attached, and a PAD attached to an FPCB. A functional layer is formed with a solder resist on a portion of the adhesive layer where the metal layer pattern is not formed. First, solder paste is applied using a squeezer to a portion where a light-emitting diode (LED) is to be mounted, and the light-emitting diode (LED) is mounted. The light-emitting diode (LED) is a type in which RGB and a driver IC are packaged, and a 4-pin LED with a height of 700㎛ of the 1212 standard was used.

[0159] Attach transparent DAM Tape (3M™ VHB™ Tape) to the outside of the panel where the light-emitting diode (LED) is mounted. The attached Dam Tape is 1 mm high and slit to 4 mm wide.

[0160] After that, the transparent silicone resin composition A manufactured according to the above manufacturing example 1 is applied using a jetting dispenser: APJ piezo type jetting valve of Mycronic Co., Ltd. 4000 mJ / cm based on 365 nm using a curing device (metal halide lamp, short wavelength cut filter applied). 2 By exposing and curing, optical laminates of Example 1 (Fig. 2b, B type) and Example 2 (Fig. 2a, A type) were manufactured, in which a protective layer having a thickness described in Table 1 below was formed.

[0161]

[0162] Example 3: Fabrication of an optical laminate

[0163] An optical laminate of Example 3 was manufactured in the same manner as the optical laminates of Examples 1 and 2, except that the transparent silicone resin composition B manufactured according to Example 2 was introduced instead of the transparent silicone resin composition A manufactured according to Example 1.

[0164]

[0165] Comparative Example 1: Fabrication of an optical laminate

[0166] An optical laminate of Comparative Example 1 was manufactured in the same manner as the optical laminates of Examples 1 and 2, except that instead of the transparent silicone resin composition A manufactured according to Manufacturing Example 1 in the protective layer, an acrylic optically transparent adhesive resin (OCR) having a thickness described in Table 1 below, as shown in FIG. 2c, was applied. The acrylic optically transparent adhesive resin (OCR) is a UV-curable resin composition containing an acrylate oligomer, a monomer, an additive, and the like, and its physical properties are as follows.

[0167] - Viscosity: 100 mPa·s (@ 25℃)

[0168] - Density: 0.85 ~ 3 g / cm 3

[0169] - Light transmittance of over 95%

[0170] - Refractive index: 1.48

[0171] - Curing shrinkage less than 15 Vol%

[0172]

[0173] Comparative Example 2: Fabrication of an optical laminate

[0174] An optical laminate of Comparative Example 2 was manufactured as shown in Fig. 2d in the same manner as the optical laminates of Examples 1 and 2 except that a protective layer was not formed.

[0175]

[0176] Protective layer material Protective layer film thickness Protective layer curing Example 1 Transparent silicone resin composition A (OCR) 0.3 mm 4000 mJ / cm based on 365 nm 2 Example 2 Transparent silicone resin composition A (OCR) (same) 1.5 mm 365 nm standard 4000 mJ / cm 2 Example 3 Transparent silicone resin composition B (OCR) 1.5 mm 365 nm standard 4000 mJ / cm 2 Comparative Example 1 Acrylic resin composition (OCR) 1.5mm 365nm standard 4000mJ / cm 2 Comparative Example 2: Without protective layer--

[0177] Experimental example

[0178] 1. Reliability Evaluation - UV Light Resistance and Weather Resistance

[0179] To evaluate UV light resistance and weather resistance, UV Lamp (UVA-340, intensity 15 W / m², 340 nm, test conditions 480 hours) and Xenon arc lamp (intensity 60 W / m 2 The optical laminates manufactured in the above examples and comparative examples were exposed to light of 300 to 4000 nm, test conditions of 240 hours, respectively. The haze at the beginning and end of exposure, the yellow index under E313-73 conditions, and the total light transmittance (%) were evaluated, and the change rates are also shown in Table 2 below.

[0180] Evaluation items Sample classification Haze Yellowness (YI) Total light transmittance (%) UV light resistance (480 hr) Example 1 Initial 0.18 0.2 84.2 End 0.1 0.21 84.1 Change rate -0.1 0.0 -0.1 Example 2 Initial 0.1 0.2 84.2 End 0.1 0.2 84.1 Change rate 0.0 0.0 0.1 Example 3 Initial 21.18 3.8 End 2.55.882 Change rate 0.54.7 -1.8 Comparative example 1 Initial 2.1 1.16 83.9 End 2.6 5.97 82.1 Change rate 0.5 4.8 -1.8 Comparative example 2 Initial 5.10.280.1 End 5.40.280.0Change rate 0.30.00.1Weatherability (240hr) Example 1Initial 0.1 0.2 84.1End 0.1 0.27 83.9Change rate 0.0 0.1 -0.2 Example 2Initial 0.1 0.2 84End 0.1 0.27 83.9Change rate 0.0 0.1 -0.1 Example 3Initial 21.183.8End 2.55.882Change rate 0.54.7-1.8Comparative Example 1Initial 1.9 1.2 82.8End 2.4 9.9 79.2Change rate 0.5 8.7 -3.6 Comparative Example 2Initial 5.40.280.0End 5.67.279.8Change rate 0.27.0-0.2

[0181] According to the experimental data in Table 2 above, the optical laminates of Examples 1 to 3 according to the present invention were evaluated to have excellent UV light resistance and weather resistance. Specifically, it was measured that there was almost no change in haze, yellowness, and total light transmittance before and after UV exposure, indicating excellent optical stability during the aging test. In addition, no changes in appearance (cracks, warping, appearance deformation, etc.) were observed, indicating that the protective layer was effectively stabilized under light irradiation conditions. In particular, in the case of Examples 1 and 2 in which the transparent silicone resin composition A from which the hydrocarbon group was removed was applied, there was no significant change in haze, yellowness, etc. before and after UV exposure, confirming better results compared to Example 3 in which the transparent silicone resin composition B from which only organic impurities were removed without removing the hydrocarbon group was applied. On the other hand, in the case of the optical laminates of Comparative Example 1, which used an acrylic resin instead of a silicone resin for the protective layer, and Comparative Example 2, which did not include a protective layer, significant changes in haze, yellowness, and total light transmittance were observed after UV exposure, indicating that the photocuring properties were noticeably lower than in the examples, and in particular, it was confirmed that there was a negative effect on yellowing. In the case of Comparative Example 2, which did not include a protective layer, some test results were poor due to damage to the optical laminate caused by UV.

[0182]

[0183] 2. LED Repair and LED Light Bleed Evaluation

[0184] For the optical laminates of the above examples and comparative examples, whether the LEDs could be repaired and whether there was light bleeding from the LEDs were checked, and the results were classified and described in Table 3 below according to the evaluation criteria below.

[0185] (1) LED light spread: Observation by luminance measurement

[0186] The luminance generated by the light reflected from the off LED of the adjacent pixel was measured after only one (lit) LED of the LED display was turned on. The measurement was performed using TOPCON SRUL1R equipment, maintaining a distance of 50 cm from the display to the measuring device and measuring the individual LED luminance under the conditions of a light reception angle of 1°. The measured luminance value from the on LED to the number of pixels away from the LED was 0.3 cd / m 2 The level of light spread was judged based on the evaluation criteria below, based on the number of LEDs up to the point shown below, and is shown in Table 3 below.

[0187] <LED 빛번짐 평가 기준>

[0188] ○: 3 Pixels or less

[0189] △: More than 3 pixels and less than 6 pixels

[0190] X: Over 6 Pixels

[0191] Sample LED RepairLED Light Bleeding (Brightness Measurement) Example 1○(Possible)○Example 2○(Possible)△Comparative Example 1Х(Impossible)Х

[0192]

[0193] (2) LED light spread: Observation by photo

[0194] The brightness of the off LED due to light spillover of the pixel image is compared relative to each other and is shown in Fig. 7. The photo on the right is a photo observing the state of the optical laminate according to the embodiment of the present invention in a state where light spillover of the off LED is not observed when a single LED is applied, and the photo on the left is a photo observing the state of the optical laminate corresponding to the comparative example of the present invention in a state where light spillover of the off LED is observed under the same conditions.

[0195]

[0196] According to the experimental data in Table 3 and FIG. 7, in the case of the optical laminates of Examples 1 and 2 according to the present invention, when some LEDs fail, only the defective portions of individual LEDs can be repaired, but this was not possible in the case of the optical laminate of the comparative example in which the protective layer was formed with an acrylic resin. In addition, in the optical laminates of Examples 1 and 2 according to the present invention, almost no light bleeding of the LED was observed, and in particular, in the case of Example 1 in which the thickness of the protective layer was formed to be about 40% of the height of the LED, it was confirmed that the light bleeding was less than that of Example 2 in which the protective layer was formed thicker than the height of the LED, since there was no reflective medium covering the LED. On the other hand, in the case of Comparative Example 1 in which an acrylic resin was coated as a protective layer, it was confirmed that the light bleeding of the LED was severe.

[0197]

[0198] 3. Evaluation of pre- and post-exposure characteristics of ultraviolet (UV) light

[0199] The optical properties before and after UV exposure of transparent silicone resin composition A manufactured according to Manufacturing Example 1 and transparent silicone resin composition B manufactured according to Manufacturing Example 2 were evaluated, and the results are shown in Table 4 below. The samples were measured on the cured products of each transparent silicone resin composition A and B applied on top of glass (NSG UFF, soda lime, 1.8 mmT). The thickness of the silicone resin after curing was 1.5 mm, and the evaluation items were as follows.

[0200]

[0201] (1) Yellowness Index (YI) evaluation

[0202] (2) Brightness and transmittance (Y) evaluation

[0203] (3) Evaluation of chromaticity values ​​for L* (brightness), a* (red-green), and b* (yellow-blue)

[0204] Yellowness (YI) evaluation was measured according to the ASTM-E313 standard using a D65 light source at 10° conditions by a spectrophotometer (UltraScan PRO, Hunter Associates Laboratory), and luminance / transmittance (Y) evaluation and chromaticity value (L*, a*, and b*) evaluation were measured using a D65 light source by a spectrophotometer (CM3700A, Minolta).

[0205] <Reliability Evaluation Criteria>

[0206] - UV 72HR exposure

[0207] - 15W, UV-B lamp

[0208] - Distance between UV lamp and sample: 12 mm

[0209]

[0210] Transparent silicone resin composition YIYL*a*b*A (before UV exposure) -0.3289.6695.86-0.05-0.04A (after UV exposure) -0.3189.6795.86-0.06-0.03B (before UV exposure) -0.2690.095.8-0.070.01B (after UV exposure) 1.0289.295.6-0.501.47

[0211] According to the experimental data in Table 4 above, when transparent silicone resin composition A was applied, no significant yellowing and / or discoloration was observed even after long-term exposure to ultraviolet (UV) rays. On the other hand, when transparent silicone resin composition B was applied, the YI (E313-73) value exceeded 1.0 and b* (D65) showed high changes exceeding 1.4 after ultraviolet (UV) exposure, indicating that transparency was reduced and, as a result, a slight decrease in transmittance for visible light occurred.

[0212] The optical laminate and transparent display according to the present invention include a protective layer formed of transparent silicone resin instead of a cover glass on one side, thereby exhibiting excellent durability against external environmental factors such as yellowing prevention, light resistance, weather resistance, heat resistance, and chemical resistance, and can secure visibility and / or optical reliability.

Claims

1. Substrate; A metal layer pattern formed on the above substrate; Light emitting diodes (LEDs); and A protective layer is included on the above metal layer pattern and the light-emitting diode; An optical laminate, characterized in that the protective layer is formed of a transparent silicone resin composition having a shore A hardness of 35 to 70 on the surface after curing.

2. In claim 1, The above transparent silicone resin composition is an optical laminate in which a hydrocarbon group at the end of the chemical formula structure is removed.

3. In claim 1, The above transparent silicone resin composition is an optical laminate from which organic impurities have been removed.

4. In claim 3, The above transparent silicone resin composition is an optical laminate, characterized in that the content of the organic impurity is 0.1% or less based on the total weight of the composition.

5. In claim 2, An optical laminate in which a terminal hydrocarbon group contained in the transparent silicone resin composition is replaced with an aryl group in removing a hydrocarbon group of the transparent silicone resin composition.

6. In claim 3, The purification or extraction for removing organic impurities of the above transparent silicone resin composition is performed by at least one selected from plasma cleaning, vacuum distillation, solvent extraction, and high-temperature distillation. An optical laminate, wherein the transparent silicone resin composition further comprises at least one selected from a UV stabilizer, an antioxidant, and a radical inhibitor as a stabilizer.

7. In claim 1, An optical laminate having a yellow index of 1.0 or less according to the ASTM E313-73 standard of the optical laminate, and b* in the CIE Lab color coordinates of the transmittance color measured using a D65 light source of 1.4 or less.

8. In claim 1, An optical laminate, characterized in that the viscosity of the transparent silicone resin composition is 1500 to 20000 mPa·s.

9. In claim 1, An optical laminate, characterized in that the thickness of the protective layer is 40% to 300% of the height of a light-emitting diode (LED).

10. In claim 1, An optical laminate, wherein the metal layer has a thickness of 3 ㎛ to 120 ㎛.

11. In claim 1, An optical laminate, wherein the metal layer comprises at least one selected from the group consisting of tin (Sn), copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), silver (Ag), iron (Fe), gold (Au), cobalt (Co), titanium (Ti), and tungsten (W).

12. In claim 1, An adhesive layer formed on one surface of the substrate; and It further includes a functional layer provided on a portion of the adhesive layer on which a metal layer pattern is not formed; An optical laminate comprising no separate member between the metal layer and the adhesive layer.

13. In claim 12, An optical laminate, wherein the adhesive layer comprises a silicone-based adhesive, has a thickness of 5 ㎛ to 50 ㎛, and has an adhesion to a substrate of 5B or greater.

14. In claim 12, An optical laminate, characterized in that the transmittance of the optical laminate is 90% or more.

15. In claim 12, An optical laminate, characterized in that the optical laminate may further include a refractive index control layer, and when the optical laminate further includes the refractive index control layer, the optical laminate has a transmittance of 91% or more.

16. In claim 12, The above functional layer is an optical laminate including a solder resist layer.

17. A transparent display comprising an optical laminate according to any one of claims 1 to 16.

18. Step (T1) of preparing a metal thin film including a substrate and a silicon-based adhesive layer formed on one surface; A step (T2) of bonding the metal thin film so that an adhesive layer is disposed on one surface of a glass substrate; A step (T3) of patterning the metal layer and developing the metal layer pattern; Step (T4) of etching and removing the portion where the above metal layer pattern is not developed; Step (T5) of forming a functional layer in a portion where the metal layer pattern is not formed; Step of mounting a light emitting diode (LED) (T6); and A method for manufacturing an optical laminate, comprising: a step of forming a protective layer (T7); 19. In claim 18, The step (T7) of forming the protective layer is a step (P1) of preparing an LED display on which the light-emitting diode (LED) is mounted; Step (P2) of masking the edge of the LED display; Step (P3) of applying a transparent silicone resin composition having a shore A hardness of 35 to 70 on the surface after curing to form a protective layer on the inside of the masking; and A method for manufacturing an optical laminate, comprising a step (P4) of photocuring the above transparent silicone resin composition.

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