Optical laminate, transparent display comprising same, and manufacturing method therefor

Abstract

The present invention relates to an optical laminate, a display comprising same, and a manufacturing method therefor, the optical laminate comprising: a glass substrate; an adhesive layer formed on the top of the glass substrate; a metal layer pattern positioned on the adhesive layer; a light emitting diode (LED) positioned on the metal layer pattern; a transparent cover positioned on the top of the light emitting diode (LED); and an organic layer on a portion of the glass substrate on which the metal layer pattern is not formed.

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] Recent technological advancements in the display market have led to a growing demand for large-area display devices. Light-emitting diodes (LEDs) are being used as billboards and electronic displays in various locations, including department stores, stores, and shopping malls. Transparent LED displays, in particular, are installed on building exterior walls and windows to display advertisements and various information. Glass- or PET (Polyester)-based transparent LED displays form circuit wiring on the PET film and arrange colored LEDs. When current is applied to the colored LEDs, they emit light. To enhance the transparency and visibility of transparent LED displays, it is necessary to reduce the visibility of the wiring while simultaneously arranging smaller LEDs.

[0004] Republic of Korea Patent No. 10-1789126 also discloses a method for manufacturing a large-area display of an LED display board using a PET substrate.

[0005] However, when mounting LEDs on narrow-pitch metal layer patterns with narrow spacing, especially thick-film patterns, using only conventional technology, short-circuit defects due to solder bridges frequently occur. Therefore, a method is needed to suppress short-circuit defects caused by solder paste flowing into adjacent metal layer patterns depending on the concentration of the solder paste during solder printing or LED mounting in a small LED SMT (Surface Mount Technology) process.

[0006]

[0007] The purpose of the present invention is to provide an optical laminate and a transparent display that improve the occurrence of short-circuit defects by forcibly suppressing the phenomenon of solder paste encroaching on an adjacent metal layer pattern by adding an organic layer having a dam structure that keeps solder paste within a certain area when mounting a light-emitting diode (LED) on a narrow-pitch metal layer pattern.

[0008] In addition, the present invention aims to provide a method for manufacturing the optical laminate and transparent display.

[0009]

[0010] The present invention relates to an optical laminate comprising a glass substrate, an adhesive layer formed on the upper portion of the glass substrate, a metal layer pattern positioned on the adhesive layer, a light emitting diode (LED) positioned on the metal layer pattern, a transparent cover positioned on the light emitting diode (LED), and an organic layer on a portion of the first substrate where the metal layer pattern is not formed.

[0011] In one embodiment of the present invention, the organic layer may be provided to cover all or part of the metal layer pattern.

[0012] In one embodiment of the present invention, the organic layer may be a solder resist.

[0013] In another embodiment of the present invention, the solder resist may be in a solid form.

[0014] In one embodiment of the present invention, a metal layer pattern having a distance between patterns of 60 to 500 μm may be included.

[0015] In one embodiment of the present invention, the thickness of the metal layer pattern may be 30 μm to 105 μm.

[0016] In one embodiment of the present invention, the metal layer pattern may include solder paste thereon.

[0017] In one embodiment of the present invention, the concentration of the solder paste may be characterized as being 100 to 220 Pa·S.

[0018] In one embodiment of the present invention, the metal layer may include at least one selected from the group consisting of copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), silver (Ag), iron (Fe), gold (Au), cobalt (Co), titanium (Ti), and tungsten (W).

[0019] In one or more embodiments of the present invention, a transparent display comprising the optical laminate is provided.

[0020] In another embodiment of the present invention, the glass substrate and the transparent cover may each independently be at least one selected from glass, quartz, borosilicate, aluminosilicate, non-alkali, soda lime glass, meshed glass, colored glass, magic mirror, and holographic glass.

[0021] In one embodiment of the present invention, when the transparent cover is made of glass, it may further include one or more selected from mesh glass, colored glass, magic mirror, and holographic glass.

[0022] In addition, the present invention comprises a step of preparing a metal film including an adhesive layer formed on one surface of a metal layer, a first protective film provided on one surface of the adhesive layer, and a second protective film provided on the other surface of the metal layer; a step of peeling off the first protective film of the metal film; a step of bonding the metal film so that the adhesive layer is disposed on one surface of a glass substrate; a step of peeling off the second protective film of the metal film;

[0023] The present invention relates to a method for manufacturing an optical laminate, comprising: a step of forming a metal layer pattern by patterning the metal layer; and a step of forming an organic layer in a portion where the metal layer pattern is not formed.

[0024] In one embodiment of the present invention, the step of forming an organic layer in a portion where the metal layer pattern is not formed may include a step of patterning a solder resist on a substrate and a step of applying solder paste to the metal layer pattern.

[0025] In one embodiment of the present invention, the step of forming the metal layer pattern may include: a step of forming a photoresist pattern on one surface of the metal layer; a step of etching an exposed area of ​​the metal layer by the photoresist pattern; and a step of peeling the photoresist pattern.

[0026] In another embodiment of the present invention, in the step of applying solder paste to the metal layer pattern, the solder paste applied on the metal layer pattern may not invade an adjacent metal layer pattern within 60 to 500 μm.

[0027] The optical laminate and transparent display according to the present invention can stably mount LED elements on a metal layer pattern having a narrow pitch of 60 to 500 μm, thereby significantly reducing the occurrence of short circuits and the defect rate during the manufacture of the optical laminate and display.

[0028]

[0029] FIGS. 1A and 1B are diagrams showing the structure of an optical laminate according to one or more embodiments of the present invention.

[0030] FIG. 2 is a flowchart illustrating a step of forming an organic layer on a portion of a substrate where a metal layer pattern is not formed, according to one or more embodiments of the present invention.

[0031] Figure 3 is an image of the shape of an optical laminate according to an embodiment and a comparative example of the present invention.

[0032] FIGS. 4A to 4C are diagrams showing the distance between patterns by photographing a metal layer pattern according to one or more embodiments of the present invention.

[0033] What each symbol represents is as follows:

[0034] 10: Metal layer pattern

[0035] 20: Substrate

[0036] 30: Organic layer

[0037] 40: Solder paste

[0038] 50: Mask

[0039]

[0040] The present invention relates to an optical laminate and a transparent display including a substrate, a formed metal layer pattern, and an organic layer in a portion of the glass substrate where the metal layer pattern is not formed, and a method for manufacturing the same, wherein LED elements can be stably mounted on a metal layer pattern having a narrow pitch of 60 to 500 μm, thereby significantly reducing the occurrence of short circuits and the defect rate during the manufacture of the optical laminate and the display.

[0041] Specifically, when mounting a light-emitting diode (LED) on a narrow-pitch metal layer pattern, the occurrence of short-circuit defects can be reduced by forcibly suppressing the phenomenon of solder paste encroaching on an adjacent metal layer pattern by adding an organic layer with a dam structure that keeps the solder paste within a certain area.

[0042]

[0043] 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.

[0044] 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. For example, "protective film" as used herein may refer to at least one of the first protective film and the second protective film.

[0045] 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.

[0046] 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.

[0047] As used herein, “substantially” may be interpreted to include not only physically identical or identical, but also within the range of error in the measurement or manufacturing process, for example, it may be interpreted to mean an error range of 0.1% or less.

[0048]

[0049] < Optical laminate and transparent display >

[0050] An optical laminate according to one or more embodiments of the present invention may include a glass substrate, an adhesive layer, a metal layer pattern, a light emitting diode (LED), a transparent cover, and an organic layer. In addition, a transparent display of the present invention may include the optical laminate.

[0051] Referring to FIGS. 1A and 1B which illustrate the structure of an optical laminate according to one or more embodiments of the present invention, in an optical laminate including a glass substrate (20), a metal layer pattern (10) formed on the glass substrate, a solder paste (40) applied to the metal layer pattern, and an organic layer (30) formed to cover a portion of the glass substrate where the metal layer pattern is not formed and a portion of the metal layer pattern, a transparent cover is positioned on the entire substrate, and more specifically, may be positioned to cover all of a light-emitting diode (LED), a metal layer pattern, and an adhesive layer, and may be positioned at the outermost portion of the optical laminate. At this time, the surface of the transparent cover may be the surface of the optical laminate and the transparent display. In FIGS. 1A and 1B, as an example of the present invention, a solder resist is used as the organic layer.

[0052] Referring to FIG. 3, when a device or LED is mounted on a substrate by applying the present invention as shown in FIG. 2, it can be visually confirmed that the phenomenon of solder paste encroaching on an adjacent metal layer pattern (10) did not occur. Specifically, unlike the conventional technology in which solder bridges are formed in an irregular shape due to the flow of solder paste, the substrate applying the present invention has an organic layer (30) having a dam structure that blocks the flow so that the solder paste is maintained only within a certain area, so that solder bridges can be applied cleanly without being formed. The narrower the spacing between the metal layer patterns, the higher the possibility that an unintended path is formed on the substrate (20), resulting in a short-circuit defect. However, when the present invention is applied, the risk of such a phenomenon is greatly reduced because the flow of solder paste is physically suppressed. Specifically, when the present invention is applied, there is no risk of a short-circuit defect even when a light-emitting diode (LED) is mounted on a fine-pitch metal layer pattern with a spacing of 60 to 500 μm. Preferably, a light emitting diode (LED) can be stably mounted on a narrow-pitch metal layer pattern with an interval of 60 to 500 μm without short-circuiting defects.

[0053] Referring to FIGS. 4A and 4C, which show the distance between patterns by photographing metal layer patterns according to one or more embodiments of the present invention, the distance between patterns may mean the shortest distance from any metal layer pattern to an adjacent metal layer pattern. Each metal layer pattern may be formed regularly or irregularly as needed and is not limited thereto. The metal layer pattern of the present invention may enable the mounting of devices since it has an area larger than the metal wiring. In the case of FIG. 4A, the case where the distance between metal layer patterns between edges is 200 μm or 300 μm is included, and in the case of FIG. 4B, the case where the distance between metal layer patterns between vertices is 100 μm or the case where the distance between edges is 500 μm is included, and in the case of FIG. 4C, the case where the distance between metal layer patterns between edges is 400 μm is included. Meanwhile, in the case of Fig. 4a, when the distance between metal layer patterns is 50 ㎛, it can be confirmed that a defect occurred in the pattern because it was too close, and with the metal layer pattern thickness of the present invention, it may be difficult to form a pattern with a distance between patterns of 50 ㎛ or less.

[0054]

[0055] Glass substrate (20)

[0056] The above glass substrate and transparent cover may be made of glass or ceramic, and are not particularly limited as long as they do not impair the optical properties of the optical laminate. For example, they may include oxide glass such as silicate glass, borate glass, or phosphate glass. In this case, there is an advantage in that heat shrinkage does not occur during subsequent processing, and a predetermined hardness can be imparted to the optical laminate.

[0057] In particular, when the glass substrate or transparent cover is made of glass, the glass can be glass with a flat surface and a transmittance of 89% or more, and specifically, quartz, borosilicate, aluminosilicate, non-alkali, soda lime glass, meshed glass, colored glass, magic mirror, and holographic glass can be used without limitation in the scope of application. In this case, the shape can be used without limitation in a specific shape such as a wafer shape or a square flat plate.

[0058] Additionally, when the transparent cover is made of glass, it may further include one or more selected from mesh glass, colored glass, magic mirror, and holographic glass.

[0059] In one or more embodiments, the glass substrate may have a thickness of 0.5 mm to 20 mm. When the thickness of the glass substrate satisfies the above range, the glass substrate can be made thin while having excellent hardness, and can prevent deformation or cracking of the metal layer. Specifically, when the thickness is less than 0.5 mm, it may be difficult to protect the metal layer or other laminated members from external impact, and when it exceeds 20 mm, it may be disadvantageous in terms of thinning or weight reduction.

[0060] In one or more embodiments, the glass substrate may have a single-layer or multi-layer structure. For example, the glass substrate may have a single-layer structure formed by a single glass substrate, but is not necessarily limited thereto, and may have a multi-layer structure in which a plurality of glass substrates are laminated.

[0061]

[0062] adhesive layer

[0063] In one embodiment, the optical laminate may include an adhesive layer on one surface of the glass substrate.

[0064] The adhesive layer may be manufactured from an adhesive layer composition containing a silicone-based adhesive. The adhesive layer composition of the present invention contains a silicone-based additive and a solvent, and may further contain additives.

[0065] The above additive may be one or more of an anchorage, a cross linker, and a catalyst.

[0066] 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.

[0067] 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.

[0068] 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.

[0069] 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.

[0070] The adhesive layer of the present invention may be formed by heating and curing the adhesive layer composition at a temperature of 100°C to 180°C.

[0071] The adhesive layer 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 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.

[0072] In one embodiment, the adhesive layer may have an adhesion strength of 5B or greater with respect to a glass substrate. As described above, the adhesive layer includes a silicone-based adhesive, and thus is characterized by excellent adhesion strength with respect to a glass substrate.

[0073] In one embodiment, the adhesion of the adhesive layer to the glass substrate may be evaluated by the measurement standard ISO 2409: Standard Test Methods for Measuring Adhesion by Tape Test.

[0074]

[0075] Metal layer pattern (10)

[0076] The above metal layer pattern may be used as an electrode in an electronic device such as a display device including the optical laminate. For example, a solder paste, which is a conductive material, may be applied onto the metal layer pattern and soldered to electrically connect the electrode of the light-emitting diode to the metal wiring of the substrate.

[0077] The metal layer on which the above pattern is formed 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 copper (Cu), aluminum (Al), nickel (Ni), chromium (Cr), silver (Ag), iron (Fe), gold (Au), cobalt (Co), titanium (Ti), and tungsten (W).

[0078] The above metal layer pattern can be formed by a known metal film process, for example, by preparing and attaching a metal film, or by using at least one method selected from the group consisting of electroless deposition, electrodeposition, sputtering, thermal evaporation, and electron beam evaporation, but is not limited thereto.

[0079] The above metal layer pattern may preferably have a thickness of 30 μm to 105 μm. If the thickness of the metal layer exceeds 105 μm, it may not be easy to form a uniform metal film or pattern, and if it is less than 30 μm, a problem of not being able to obtain conductivity for smooth operation may occur. In particular, in the case of a metal layer pattern satisfying the above preferred thickness, it may be difficult to form a pattern-to-pattern interval of 50 μm or less, and thus it may be more suitable for forming a thick-film pattern rather than a fine pattern. Therefore, in forming the metal layer pattern of the present invention, it is particularly preferable to form it so that the minimum pattern-to-pattern interval exceeds 50 μm.

[0080]

[0081] Organic layer (30)

[0082] The organic layer is formed on the adhesive layer where the metal layer pattern is not formed, i.e., on the adhesive layer exposed by etching the metal layer when forming the metal layer pattern. In addition, the organic layer may be formed to include a portion where the metal layer pattern is not formed and a portion of the metal layer pattern. For example, the organic layer may be formed by filling a portion where the metal layer pattern is not formed, as in Fig. 1a, and may be formed in a form where it is connected to a portion where the metal layer pattern is not formed on the adhesive layer and is partially laminated on the metal layer, as in Fig. 1b.

[0083] More specifically, the organic layer may be formed to cover all or part of the metal layer pattern. In one example of the present invention, when there are multiple metal layer patterns, the organic layer may be formed to cover all or only part of each metal layer pattern. More preferably, as shown in FIG. 1A, the organic layer may be formed to cover all of a portion of the substrate where the metal layer pattern is not formed, or as shown in FIG. 1B, the organic layer may be formed to cover a portion of the substrate where the metal layer pattern is not formed and a part of the metal layer pattern. In this case, the metal layer pattern that is not covered or is only partially covered by the organic layer may be for mounting a light emitting diode (LED). In this way, when the organic layer is formed to cover only part of the metal layer pattern, the degree to which the organic 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).

[0084] In addition, by forming the organic layer, it is possible to prevent diffuse reflection caused by the adhesive layer. Specifically, as described above, a metal layer pattern is formed on one surface of the adhesive layer of the present invention, and the metal layer pattern may have a surface roughness (Rz) of 0.1 to 20 μm. At this time, if the adhesive layer includes a silicone-based adhesive layer, and the surface shape of the metal layer is directly reflected in the adhesive layer, when the metal layer is patterned and then peeled off, the exposed adhesive layer surface has irregularities derived from the metal layer having a certain surface roughness, and this causes light scattering and increases haze when applied to a transparent display. Therefore, by providing an organic layer in a portion of the adhesive layer where the metal layer pattern is not formed so that the surface irregularities of the adhesive layer do not appear, diffuse reflection can be prevented, haze can be reduced, and visibility can be improved.

[0085] In this respect, the organic layer may have a surface roughness (Rz) of 5.0 μm or less. If the surface roughness (Rz) exceeds 5.0 μm, diffuse reflection occurs, increasing haze and causing a problem of blurry perception.

[0086] The organic layer may include a solder resist. More specifically, the organic layer may be formed by a solder resist. The solder resist may be formed by any one of thermal curing, photocuring, and thermal curing, and may also be either a liquid type or a film type.

[0087] If the solder resist is of a liquid type, it may be manufactured from a solder resist composition containing a binder resin, a photopolymerizable compound, a photopolymerization initiator, a pigment, a dye, a solvent, and / or other additives. If the solder resist is of a liquid type, the printing and drying processes must be repeated during manufacturing, and therefore, in the present invention, it is more preferable to apply a solid type.

[0088] When the solder resist is of a solid type, more preferably a film type, it may include a protective film, a photosensitive resin layer, and a base film. When the solder resist is of 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, so that a light-emitting diode (LED) can be efficiently mounted, and it has a high resolution. The base film includes a polyester film such as polyethylene terephthalate and is used as a support. The protective film functions as a protective layer to prevent damage to the resist, but is not limited thereto. The photosensitive resin layer may use the same components as the liquid type solder resist described above.

[0089] The above organic layer can be patterned using a solder resist using a photolithography method to form a structure that only partially covers 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.

[0090] As described above, when the organic layer partially covers the metal layer pattern, the thickness laminated on the metal layer pattern may be 1 µm to 3 mm.

[0091]

[0092] solder paste (40)

[0093] The solder paste (40) of the present invention is applied and soldered on a metal layer pattern, and the electrodes of the light-emitting diode and the metal wiring of the substrate can be electrically connected by the solder paste, and is also called solder cream. The solder paste may contain about 85 wt% to 90 wt% of solder powder in powder form and about 10 wt% to 15 wt% of paste flux. The paste flux may be included to prevent the surface of the metal layer pattern from coming into contact with the air and forming an oxide layer, thereby facilitating the mounting of the device.

[0094] As solder powder, a generally commercially available product can be used, and it can also be manufactured and applied directly using a conventional spraying method. The solder powder may be a commonly used Sn / Pb alloy (tin / lead alloy) powder, but considering environmental aspects, it may also be an alloy powder that does not contain lead. Lead-free solder powders that can be used in the present invention include Sn / Ag, Sn / Ag / Cu, Sn / Cu, Sn / Zn, Sn / Zn / Bi, Sn / Zn / Bi / In, Sn / Bi, Sn / Bi / Cu, and Sn / In, and these may be used alone or in combination of two or more. As the solder powder used in the solder paste according to the present invention, a lead-free solder powder is preferably used, and more preferably, a solder powder in which bismuth (Bi) + copper (Cu) and tin (Sn) are mixed in a ratio of 8:2 to 5:5 can be used. Specific examples include an alloy composed of 30 wt% Sn and 70 wt% Bi+Cu as solder powder, an alloy composed of 40 wt% Sn and 60 wt% Bi+Cu, or an alloy composed of 50 wt% Sn and 50 wt% Bi+Cu, and product names include, but are not limited to, SBX02.

[0095] The solder paste can be adjusted in concentration by adding a diluent, and preferably, when the concentration is 100 to 220 Pa·S, the flowability is suitable, which is advantageous in preventing short circuits due to suppression of solder bridge formation. If the solder paste is less than the above concentration range, it is too dilute, and even though an organic layer that functions as a dam between metal layer patterns exists, it is easy to invade the surrounding metal layer patterns, and the density may be low, which may not be suitable in terms of conductivity. In addition, if the solder paste exceeds the above concentration range, the SMT (surface mount technology) process may not be possible.

[0096] Accordingly, the solder paste according to the present invention may optionally further include an organic solvent as a diluent. The organic solvent is specifically a hydrocarbon (e.g., dodecane, tetradecane); an aromatic hydrocarbon (e.g., benzene, toluene, xylene, trimethylbenzene, butyl benzoate, dodecylbenzene); a ketone (e.g., methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone); an ether (e.g., tetrahydrofuran, 1,4-dioxane and tetrahydrofuran, 1,3-dioxalane, dipropylene glycol dimethyl ether); an alcohol (e.g., 2-methoxyethanol, 2-butoxyethanol, methanol, ethanol, isopropanol, α-terpineol, benzyl alcohol, 2-hexyldecanol); Esters (e.g., ethyl acetate, ethyl lactate, butyl acetate, diethyl adipate, diethyl phthalate, diethylene glycol monobutyl acetate, propylene glycol monomethyl ether acetate, ethyl lactate, methyl 2-hydroxyisobutyrate, propylene glycol monomethyl ether acetate); and, amides (e.g., N-methylpyrrolidone, N,N-dimethylformamide, and N,N-dimethylacetamide); glycol derivatives (e.g., cellosolve, butyl cellosolve); glycols (e.g., ethylene glycol; diethylene glycol; dipropylene glycol; triethylene glycol; hexylene glycol; 1,5-pentanediol); glycol ethers (e.g., propylene glycol monomethyl ether, methyl carbitol, butyl carbitol); rosin resins; and petroleum solvents (e.g., petroleum ether, naphtha), etc., and preferably, a rosin series resin can be used, but is not limited thereto.

[0097] The solder paste may optionally further contain auxiliary additives such as a rheology modifier or thickener to give it a creamy form.

[0098]

[0099] Light-emitting diode (LED)

[0100] The light emitting diode (LED) of the present invention can be applied to any known light emitting diode (LED) without limitation. In particular, the present invention may be a light emitting diode (LED) that must be mounted on a substrate having a metal layer pattern with a narrow pitch, particularly a thick film pattern, and preferably, it can be applied to a metal layer pattern with a distance between patterns of 60 to 500 μm. Using the present invention, it is possible to manufacture an optical laminate and display that significantly reduces short-circuit occurrence and defect rate, particularly when mounting a 4-pin to 6-pin light emitting diode.

[0101]

[0102] <Method for manufacturing optical laminate>

[0103] A method for manufacturing an optical laminate according to an embodiment of the present invention may include the steps of: preparing a metal film including a silicone-based adhesive layer formed on one surface of a metal layer, and including a first protective film provided on one surface of the silicone-based adhesive layer and a second protective film provided on the other surface of the metal layer; peeling off the first protective film of the metal film; bonding the metal film so that the adhesive layer is disposed on one surface of a glass substrate; peeling off the second protective film of the metal film; patterning the metal layer to form a metal layer pattern; and forming an organic layer in a portion where the metal layer pattern is not formed.

[0104]

[0105] Steps to prepare a metal film

[0106] The above protective film may be provided to protect the surface of the metal layer and / or the adhesive layer from the outside, and may be provided in the form of, for example, a first protective film formed on one side of the adhesive layer to protect the surface of the adhesive layer, and a second protective film formed on one side of the metal layer to protect the surface of the metal layer.

[0107] In one embodiment, the protective film may be used as a single-layer structure formed of one layer, but is not limited thereto, and may also be used as a multi-layer structure in which one or more protective films are continuously laminated.

[0108] In one embodiment, the protective film may be formed by laminating a second protective film and a first protective film on one surface of the metal layer and the adhesive layer, respectively, using a laminator.

[0109] The above protective film is not particularly limited as long as it is for protecting the surface of the metal layer and / or the adhesive layer, and for example, polyethylene terephthalate (PET), polyethylene isophthalate (PEI), polyethylene naphthalate (PEN), polybutylene terephthalate (PBT), diacetyl cellulose, triacetyl cellulose (TAC), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polymethyl acrylate (PMA), polyimide (PI), polymethyl methacrylate (PMMA), polyethyl acrylate (PEA), polyethyl methacrylate (PEMA), and cyclic It may include at least one selected from the group consisting of cyclic olefin polymers (COPs), and in terms of ease of acquisition and processing convenience, polyethylene terephthalate (PET), triacetyl cellulose (TAC), polycarbonate (PC), polyimide (PI), and cyclic olefin polymers (COPs) can be preferably used.

[0110] The thickness of the above protective film is not particularly limited and may be, for example, 10 μm to 200 μm.

[0111] Meanwhile, the metal film described above is exemplified by a metal film having a protective film on one side of the metal layer and the adhesive layer, but is not limited thereto. For example, it may include only one protective film among the protective film formed on one side of the metal layer and the protective film formed on one side of the adhesive layer.

[0112]

[0113] Step of peeling off the first protective film of the metal film

[0114] Specifically, the step of peeling off the first protective film provided on the metal film may be peeling off the first protective film disposed on the lower surface of the adhesive layer of the metal film.

[0115] The peeling of the first protective film can be appropriately performed within a range that does not harm the purpose of the present invention, and a method used in a conventional peeling process of a release film can also be used.

[0116]

[0117] Step of bonding the above metal film

[0118] The step of bonding the metal film so that the adhesive layer is disposed on one surface of the glass substrate may be bonding the surface of the adhesive layer exposed to the outside by peeling off the first protective film onto one surface of the glass substrate.

[0119] Bonding of the above adhesive layer and the glass substrate can be appropriately performed within a range that does not harm the purpose of the present invention, and can be bonded using, for example, a laminator or the like.

[0120]

[0121] Step of peeling off the second protective film of the metal film

[0122] The step of peeling off the second protective film provided on the above metal film may be peeling off the second protective film disposed on the upper surface of the metal layer of the metal film.

[0123] The peeling of the second protective film may be performed by substantially the same method as the peeling of the first protective film.

[0124] Meanwhile, the method for manufacturing the optical laminate described above is described by way of example, a method for manufacturing the optical laminate using a metal film, but is not necessarily limited thereto.

[0125] For example, in another embodiment of the present invention, if the metal film does not have a second protective film, the step of peeling off the second protective film provided on the metal film may be omitted.

[0126]

[0127] Step of forming a metal layer pattern

[0128] The step of forming a metal layer pattern of an optical laminate according to one embodiment of the present invention may include the steps of forming a photoresist pattern on one surface of the metal layer; etching an exposed area of ​​the metal layer by the photoresist pattern; and peeling off the photoresist pattern.

[0129] Specifically, the step of forming a photoresist pattern on one surface of the metal layer may include a step of applying a composition for forming a photoresist pattern onto the metal layer by spin coating, slit coating, inkjet printing, etc., a step of drying and heat-treating the applied composition for forming a photoresist pattern 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 an exposed area or a non-exposed area, thereby forming a photoresist pattern.

[0130] The step of forming the above photoresist pattern can be performed by a known method, and details are omitted.

[0131] The step of etching the exposed area of ​​the metal layer by the above photoresist pattern is not particularly limited and may be performed by a dry etching process or a wet etching process.

[0132] In one embodiment, the wet etching process may be performed using an etchant including at least one selected from the group consisting of nitric acid, phosphoric acid, and acetic acid. As described above, the adhesive layer is characterized by including a silicon-based adhesive, and thus has excellent chemical resistance to an etchant including at least one selected from the group consisting of nitric acid, phosphoric acid, and acetic acid. Therefore, when the etching process is performed by wet etching using an etchant including at least one selected from the group consisting of nitric acid, phosphoric acid, and acetic acid, not only is the etching performance for the metal layer excellent, but even if the adhesive layer located under the metal layer is exposed to the etchant, damage (physical and chemical damage and clouding phenomenon) to the adhesive layer may not occur.

[0133] The above dry etching process or wet etching process can be performed by a known method, and details are omitted.

[0134] The step of stripping the above photoresist pattern may be performed by immersing the substrate on which the resist pattern is formed in a resist stripping solution, or by spraying the stripping solution onto the substrate. In addition, in this case, physical processing such as ultrasonic irradiation or contact with a brush that rotates or swings left and right may be used in combination.

[0135] In one embodiment, the resist stripping conditions may be a temperature of about 15°C to 100°C, preferably 30°C to 70°C, and the immersion or spraying time may be preferably about 1 minute to 20 minutes, but is not limited thereto and may be appropriately modified according to the needs of the user.

[0136] In one embodiment, after the resist stripping solution treatment, an additional cleaning process may be performed to remove any stripping solution remaining on the substrate. The cleaning process may be performed in the same manner as the stripping process described above, except that water or isopropyl alcohol is used instead of the stripping solution.

[0137]

[0138] Step of forming an organic layer in a part where a metal layer pattern is not formed

[0139] In addition, according to a method for manufacturing an optical laminate according to an embodiment of the present invention, the step of forming an organic layer in a portion where the metal layer pattern is not formed may include a step of patterning a solder resist on a substrate and a step of applying solder paste on the metal layer pattern.

[0140] In one embodiment of the present invention, the step of forming the organic layer may be a step of forming using either a liquid type or a solid type solder resist, and preferably a step of forming a film type solder resist layer, but the forming method is not particularly limited.

[0141] FIG. 2 is a flowchart illustrating a step of forming an organic layer in a portion where the metal layer pattern is not formed and a step of applying solder paste according to one or more embodiments of the present invention. Referring to FIG. 2, a metal layer pattern (10) is formed on a substrate, and a solder resist is applied to an upper portion of the substrate (20). Next, the substrate is exposed to light while covering the portion except for the metal layer pattern (10), and the portion exposed to light as a result of the exposure is dissolved and removed. The solder resist is photocured or thermally cured only in a portion that is not selectively exposed by the mask, and remains in the form of a dam in a subsequent developing process. As a result of the developing process, the surface of the substrate is selectively exposed to form an opening, and a dam-like shape is formed with the organic layer (30). Afterwards, through the SMT (surface mount technology) process, a mask (50) is placed on the area except for the area where solder paste is to be applied, and then solder paste is applied using a squeezer. By using the organic layer (30) filled in the area where the metal layer pattern (10) on the substrate is not formed, solder paste (40) can be applied only to the opening without invading the adjacent metal layer pattern (10).

[0142]

[0143] In addition, the method for manufacturing an optical laminate according to one embodiment of the present invention may further include a step of mounting a light emitting diode (LED) on the optical laminate described above.

[0144]

[0145] Transparent Display and Manufacturing Method

[0146] The present invention includes a transparent display manufactured using the optical laminate of the present invention described above and a manufacturing method thereof.

[0147] Specifically, the present invention relates to a transparent display including the optical laminate described above and a light emitting diode (LED). FIGS. 1A and 1B are diagrams showing an example of a transparent display of the present invention. Referring to FIGS. 1A and 1B, the transparent display of the present invention has a form in which a light emitting diode (LED) is formed in a portion of a patterned metal layer of an optical laminate in which an organic layer is not formed. More specifically, the portion of a patterned metal layer of a metal film substrate in which an organic layer is not formed may further include solder paste, and a light emitting diode (LED) may be mounted through the solder paste. The arrangement interval or density of the light emitting diodes (LED) 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 a 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 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.

[0148] The present invention may further include a structure and method including an overcoat layer covering the upper portion of the light-emitting diode (LED) or the entire transparent display. The overcoat layer may be made of any material known in the art without limitation, and its thickness is not particularly limited as long as it is at a level commonly applied by those skilled in the art.

[0149] 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 advantage of being particularly suitable for use in devices that can be exposed to the external environment for long periods of time, such as transparent displays, in terms of excellent heat resistance and reliability in high temperature and high humidity environments.

[0150]

[0151] 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. In addition, "%" and "part" indicating the content below are based on weight unless specifically stated.

[0152]

[0153] Example I.1 and Comparative Example I.1: Fabrication of an optical laminate

[0154] Example I.1

[0155] Silicone (DOWSIL) TM A composition having a silicone adhesive content of 50% was prepared using 96-083 Silicone Adhesive Kit, DOW; solid content 70%), and then the composition was stirred with a stirrer to prepare an adhesive layer composition.

[0156] Afterwards, the adhesive layer composition was applied on one surface of a copper metal substrate (surface roughness (Rz) 9.0 ㎛) with a thickness of 30 ㎛ by the gravure coating method, and then cured at 150°C for 2 minutes to produce a metal film having a silicone adhesive layer with a thickness of 10 ㎛ formed on one surface of the metal substrate.

[0157] Afterwards, the adhesive layer of the metal film was placed on one side of a glass substrate having a thickness of 2 mm, and then the metal film was bonded using a sheet to sheet method to laminate the metal layer.

[0158] Afterwards, a metal layer pattern was formed by patterning the metal layer using photolithography. The formed metal layer pattern was a narrow-pitch metal layer pattern, with a distance between patterns of 140 μm.

[0159] An organic layer was formed using solder resist on a portion of the adhesive layer where no metal layer pattern was formed, thereby manufacturing an optical laminate of Example I.1.

[0160] Specifically, the solder resist was prepared by mixing a monomer (ELVAROY TM, manufacturer: DOW), a binder (VORAMERTM, manufacturer: DOW), and a photoinitiator (Irugacure 907, manufacturer: Ciba Specialty Chemical (Co., Ltd.)) in a 5:3:2 ratio, and then mixing the PGMEA solvent and the monomer, binder, and photoinitiator mixture in a 5.5:4.5 ratio to prepare a liquid solution. This was uniformly applied to the top of the film and dried in an 85°C oven for 6 minutes to produce a transparent DFSR (Dry Film Solder Resist), which was then attached to the substrate. At this time, the thickness of the organic layer was 50 μm.

[0161] Afterwards, the above transparent DFSR was patterned using a photolithography method to form a pattern of the DFSR, and then, through the SMT (surface mount technology) process, a mask (50) was placed over the area except for the area where solder paste was to be applied, and then solder paste was applied using a squeezer.

[0162]

[0163] Comparative Example I.1

[0164] An optical laminate was manufactured in the same manner as in Example I.1 above, except that the organic layer was not formed.

[0165]

[0166] Test Example I: Photographing the shape of an optical laminate

[0167] For the optical laminates of Example I.1 and Comparative Example I.1, their shapes were photographed and shown in Fig. 3.

[0168] Referring to Fig. 3, in the case of the left substrate, where solder bridges were formed in an irregular shape due to the flow of solder paste, a short-circuit defect occurred. Specifically, in order to mount one light-emitting diode (LED), all four metal layer patterns must be in normal contact, but in the case of the left substrate using the conventional technology, one or more solder bridges were formed, which confirmed the occurrence of a defect. Therefore, in order to control the solder paste application process so that an unintended solder bridge is not formed in the metal layer pattern with a narrow pitch and a short-circuit occurs, a very precise process is required, which complicates the process. On the other hand, in the case of the right substrate to which the present invention is applied, an organic layer with a dam structure that keeps the solder paste within a certain area is formed, so it can be confirmed that not a single unintended path is formed between the metal layer patterns on the substrate. The reason why no short circuit defect occurred on the right substrate is because the flow of solder paste was physically suppressed, and since an organic layer was formed in the area except for the upper portion of the metal layer pattern on which the light-emitting diode (LED) is to be mounted after solder paste application, it is possible to manufacture an optical laminate with a significantly reduced risk of short circuit defect without having to go through an overly precise process when applying solder paste, which is advantageous in the production process. When the present invention is applied in this way, as shown in the left substrate of Fig. 3, there is no risk of short circuit defect even when an LED is mounted on a narrow-pitch metal layer pattern with a pattern distance of 140 μm.

[0169]

[0170] Examples II.1 to II.8 and Comparative Examples II.1 to II.8

[0171] Examples II.1 to II.8

[0172] Example II.1 was manufactured in the same manner as Example I.1 except that the metal layer pattern was manufactured to a thickness of 70 μm and the distance between patterns was manufactured to be 50 μm.

[0173] Examples II.2 to II.8 were manufactured in the same manner as Example II.1, except that the inter-pattern distance was formed as shown in Table 1.

[0174] Presence or absence of organic layer Pattern distance (㎛) Example II.1050 Example II.2060 Example II.30100 Example II.40200 Example II.50300 Example II.60400 Example II.70500 Example II.80600

[0175]

[0176] Comparative Examples II.1 to II.8

[0177] Comparative Example II.1 was manufactured in the same manner as Comparative Example I.1 except that the metal layer pattern was manufactured to have a thickness of 70 μm and the distance between patterns was manufactured to be 50 μm.

[0178] Comparative Examples II.2 to II.8 were manufactured in the same manner as Comparative Example II.1, except that the distance between patterns was formed as shown in Table 2.

[0179] Distance between patterns with and without organic layer composition (㎛) Comparative example II. 1X50 Comparative example II. 2X60 Comparative example II. 3X100 Comparative example II. 4X200 Comparative example II. 5X300 Comparative example II. 6X400 Comparative example II. 7X500 Comparative example II. 8X600

[0180]

[0181] Test Example II. Solder Bridge Formation Evaluation

[0182] For the manufactured optical laminate, solder paste was applied on the metal layer pattern, and the degree of solder bridge formation was evaluated visually, as shown in Table 3.

[0183] Solder paste was manufactured with concentrations of 90 Pa·S and 180 Pa·S by mixing rosin-based resin as a diluent with OM525 SBX02 Type4 product with concentrations of 180 to 220 Pa·S.

[0184] - ○: No solder bridge occurs

[0185] - △: Solder bridge occurrence less than 5%

[0186] - X: Solder bridge exceeds 5%

[0187]

[0188] Solder bridge evaluation configuration Solder paste concentration 90 Pa·S Solder paste concentration 180 Pa·S Example II.1 Pattern formation not possible Pattern formation not possible Example II.2 △○ Example II.3 △○ Example II.4○○ Example II.5○○ Example II.6○○ Example II.7○○ Example II.8○○ Comparative example II.1- Pattern formation not possible Comparative example II.2-X Comparative example II.3-X Comparative example II.4-X Comparative example II.5-X Comparative example II.6-X Comparative example II.7-X Comparative example II.8-○

[0189] Referring to Example II.1 and Comparative Example II.1 of Table 3, in the case of the metal layer pattern of the present invention, it was impossible to form a thick-film pattern with a distance between patterns of 50 μm. In addition, according to Examples II.2 to II.7, in the case of a metal layer pattern formed with a distance between patterns of 60 to 500 μm, it is possible to suppress solder bridge formation even when using a solder paste having a concentration of less than 100 Pa·S due to the presence of an organic layer, and it can be confirmed that it is even better in terms of suppressing shoulder bridge formation when using a solder paste having a concentration of 100 to 220 Pa·S.

[0190] On the other hand, according to comparative examples II.2 to II.7 of Table 3, in the case of metal layer patterns formed without including an organic layer, solder bridges were formed at an interval of 60 to 500 μm between patterns, resulting in defects, even though solder paste having a concentration of 100 to 220 Pa·S was used.

[0191] Meanwhile, according to Example II.8 and Comparative Example II.8 manufactured with a distance between patterns of 600 μm, it was confirmed that when the distance between patterns is 600 μm, the distance is so far that solder bridges do not occur regardless of the formation of the organic layer or the concentration of the solder paste.

[0192]

[0193] The optical laminate and transparent display according to the present invention can stably mount LED elements on a metal layer pattern having a narrow pitch of 60 to 500 μm, thereby significantly reducing the occurrence of short circuits and the defect rate during the manufacture of the optical laminate and display.

Claims

1. Glass substrate; An adhesive layer formed on top of the glass substrate; A metal layer pattern positioned on the above adhesive layer; A light emitting diode (LED) positioned on the above metal layer pattern; A transparent cover positioned above the light emitting diode (LED); and An optical laminate comprising an organic layer on the glass substrate, wherein the metal layer pattern is not formed in a portion thereof.

2. In claim 1, An optical laminate, wherein the organic layer is provided to cover all or part of the metal layer pattern.

3. In claim 1, An optical laminate, wherein the organic layer is formed using a solder resist.

4. In claim 3, An optical laminate wherein the solder resist is in solid form.

5. In claim 1, An optical laminate comprising a metal layer pattern having an inter-pattern distance of 60 ㎛ to 500 ㎛.

6. In claim 1, An optical laminate, wherein the thickness of the metal layer pattern is 30 ㎛ to 105 ㎛.

7. In claim 1, An optical laminate having a metal layer pattern including solder paste on top.

8. In claim 7, An optical laminate, characterized in that the concentration of the solder paste is 100 to 220 Pa·S.

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

10. A transparent display comprising an optical laminate according to any one of claims 1 to 9.

11. In claim 10, A transparent display, wherein the glass substrate and the transparent cover are each independently at least one selected from glass, quartz, borosilicate, aluminosilicate, non-alkali, soda lime glass, meshed glass, colored glass, magic mirror, and holographic glass.

12. In claim 10, A transparent display, wherein the transparent cover is made of glass, and further comprises at least one selected from mesh glass, colored glass, magic mirror, and holographic glass.

13. A step of preparing a metal film including an adhesive layer formed on one surface of a metal layer, a first protective film provided on one surface of the adhesive layer, and a second protective film provided on the other surface of the metal layer; A step of peeling off the first protective film of the above metal film; A step of bonding the metal film so that an adhesive layer is disposed on one surface of a glass substrate; A step of peeling off the second protective film of the above metal film; A step of forming a metal layer pattern by patterning the metal layer; and A method for manufacturing an optical laminate, comprising: forming an organic layer in a portion where the metal layer pattern is not formed.

14. In claim 13, the step of forming an organic layer in a portion where the metal layer pattern is not formed comprises the step of patterning a solder resist on a substrate, and A method for manufacturing an optical laminate, comprising the step of applying solder paste on the metal layer pattern.

15. In claim 13, The step of forming the above metal layer pattern includes a step of forming a photoresist pattern on one surface of the metal layer; A step of etching the exposed area of ​​the metal layer by the above photoresist pattern; and A method for manufacturing an optical laminate, comprising: a step of peeling off the photoresist pattern.

16. In claim 14, A method for manufacturing an optical laminate, wherein, in a step of applying solder paste to the metal layer pattern, the solder paste applied on the metal layer pattern does not invade an adjacent metal layer pattern within 60 to 500 μm.

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