buffer film

Abstract

This document discloses a buffer film and an organic light-emitting device (OLED) incorporating the same. In some embodiments, the buffer film comprises a porous metal sheet with an average reflectance of 50% or less to light in the wavelength range of 400 nm to 800 nm. The buffer film can exhibit the heat dissipation characteristics, electromagnetic shielding characteristics, and shock resistance (or shock mitigation characteristics) required by OLEDs. The buffer film can ensure the characteristics required by OLEDs without increasing the cost, process complexity, and thickness of OLEDs.

Description

Technical Field

[0001] This application is filed under International Application No. PCT / KR2021 / 011802, filed on September 2, 2021, pursuant to 35 U.SC §371, and claims priority to Korean Patent Application No. 10-2020-0111885, filed on September 2, 2020; Korean Patent Application No. 10-2020-0116206, filed on September 10, 2020; and Korean Patent Application No. 10-2020-0143626, filed on October 30, 2020, the disclosures of which are incorporated herein by reference.

[0002] This disclosure relates to buffer membranes and their uses. Background Technology

[0003] Because organic light-emitting devices can emit light themselves, they are advantageous compared to other devices such as LCDs (liquid crystal devices) in terms of achieving thin devices, and are also advantageous in configuring flexible devices such as foldable or rollable devices.

[0004] However, organic light-emitting devices are susceptible to external shocks, such as drop impacts, and as the frequency of their application in mobile devices increases, the problems caused by external shocks become increasingly significant.

[0005] As devices equipped with organic light-emitting devices are made thinner, problems such as electromagnetic waves and heat generated by the organic light-emitting devices or the electronic components connected to them also increase.

[0006] Organic light-emitting devices may include a substrate on which an organic light-emitting layer is formed, and typically include a driving circuit portion for driving the organic light-emitting layer and electronic components for transmitting signals to the driving circuit portion. When electronic components are present, they may be located on the back side of the substrate. Figure 1 As exemplarily shown, in the aforementioned case, the organic light-emitting device may have a structure in which an organic light-emitting layer 20 is present on a first surface surrounding a substrate 10 and an electronic component 30 is present on a second surface.

[0007] In such a structure, problems may arise when heat generated in the organic light-emitting layer or driving circuit is transferred to the electronic components, or conversely, when heat generated in the electronic components or battery is transferred to the organic light-emitting layer or driving circuit. Therefore, it is necessary to effectively manage the heat generated as described above.

[0008] Furthermore, even when electromagnetic waves generated by electronic devices are transmitted to the organic light-emitting layer, the performance may deteriorate, and the electromagnetic waves also adversely affect the users of the device.

[0009] Patent document 1 discloses a structure in which a buffer member made of urethane or the like is disposed under the substrate of an organic light-emitting device to cope with external impact problems.

[0010] However, the structure disclosed in Patent Document 1 is insufficient to ensure adequate impact resistance when applied to mobile devices, etc.

[0011] Furthermore, the structure disclosed in Patent Document 1 does not take into account electromagnetic waves or heat generated in the device.

[0012] To address electromagnetic wave or thermal issues, one could consider adding components to the device that can additionally shield electromagnetic waves or address thermal problems. However, introducing such components makes it difficult to configure devices with thin profiles.

[0013] [Existing Technical Documents]

[0014] [Patent Literature]

[0015] (Patent Document 1) Korean Patent Publication No. 10-0965251 Summary of the Invention

[0016] Technical issues

[0017] This disclosure is intended to provide buffer films and their uses, and in particular, to provide buffer films and their uses for organic light-emitting devices.

[0018] Technical solution

[0019] Unless otherwise stated, the physical properties mentioned in this specification that are affected by the measurement temperature are those measured at room temperature.

[0020] The term room temperature refers to the natural temperature without heating or cooling, meaning, for example, any temperature in the range of 10°C to 30°C, or around 23°C or around 25°C. Furthermore, in this specification, unless otherwise stated, the unit of temperature is Celsius (°C).

[0021] Unless otherwise stated, the physical properties mentioned in this specification refer to properties where the measurement pressure affects the results, and are measured at atmospheric pressure.

[0022] The term atmospheric pressure refers to natural pressure that is not controlled by means of pressurization and depressurization, and is usually at atmospheric pressure, which can be around 900 hPa to 1,200 hPa.

[0023] In the case of measuring the physical properties that affect the results of humidity measurement, the relevant physical properties are those measured under natural humidity conditions without special control at room temperature and normal pressure.

[0024] This disclosure provides a buffer film. The buffer film of this application can be applied to a variety of applications requiring shock mitigation. In one example, the buffer film can be effectively used in organic light-emitting devices (hereinafter, OLEDs).

[0025] The buffer membrane of this disclosure includes a porous metal sheet. The term porous metal sheet means a metal sheet having one or more or two or more pores formed therein or on its surface, wherein the metal sheet has a shape commonly referred to as a membrane, sheet, or layer.

[0026] Porous metal sheets contain metal as a major component. Therefore, the weight percentage of metal based on the total weight of the porous metal sheet can be approximately 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, or 95% by weight or more. Since porous metal sheets can contain only metal, the upper limit for the weight percentage of metal is 100% by weight. Here, the categories of metal also include so-called metal alloys. Furthermore, metal can also be contained in the porous metal sheet in the form of oxides, nitrides, or oxynitrides.

[0027] Porous metal sheets, due to their porous structure, can buffer external impacts. Furthermore, by selecting the appropriate metal material for the porous metal sheet to ensure the required thermal conductivity characteristics in the device, heat dissipation can be guaranteed. Additionally, the voids included in the porous metal sheet can also dissipate or shield electromagnetic waves. Therefore, the buffer film of this disclosure can exhibit the required heat dissipation characteristics, electromagnetic wave shielding characteristics, shock resistance, and shock mitigation characteristics of a device using only a porous metal sheet. Thus, the buffer film of this disclosure enables the resolution of various problems that may arise in OLEDs and similar applications without increased cost, process complexity, or thickness.

[0028] The porous metal sheet included in the buffer film of this disclosure can exhibit an average reflectivity of 50% or less for light in the wavelength range of 400 nm to 800 nm. In another example, the average reflectivity can also be around 49% or less, 47% or less, 45% or less, 43% or less, 41% or less, 39% or less, 37% or less, 35% or less, 33% or less, 31% or less, or 29% or less. Such low reflectivity is particularly necessary when the buffer film is applied to OLEDs. OLEDs typically include reflective electrodes or reflective plates for light emission, where such reflective electrodes or reflective plates reduce the visibility of the device, and therefore various methods have been developed to address this problem. When a metallic material is applied to the buffer film, the above problems may be exacerbated due to the inherent reflective properties of the metal. In this disclosure, by adjusting the reflectivity of the porous metal sheet as described above, the buffer film can exhibit the desired performance without degrading the optical properties of OLEDs, etc.

[0029] The average reflectivity of porous metal sheets for light in the wavelength range of 400 nm to 800 nm is advantageous as this value decreases, thus there is no particular limitation on its lower limit. Considering the reflective properties of general metallic materials, for example, the average reflectivity can be around 10% or more, 15% or more, or around 25% or more.

[0030] The average reflectance is obtained by measuring the reflectance at intervals of 0.5 nm from 400 nm to 800 nm and averaging these values; specifically, it is the value measured by the method presented in the example.

[0031] There are no particular limitations to the methods described above for adjusting the reflectivity of porous metal sheets. The inherent reflective properties exhibited by metallic materials are known for each metal, and these properties can be considered to achieve the above reflectivity by selecting appropriate metals. If necessary, two or more metals can be used to adjust the reflectivity, as described below.

[0032] Porous metal sheets can also have a diameter of 1.0 × 10⁻⁶. -5The specific resistance is Ωcm or greater. The buffer film of this disclosure can be included in electronic / electrical devices such as OLEDs to ensure buffering characteristics, heat dissipation characteristics, and / or electromagnetic wave shielding characteristics. When the specific resistance of the porous metal sheet is adjusted to the above range, suitable insulating sites or pass-through potentials can be formed in the device through the porous metal sheet. Therefore, by adjusting the specific resistance of the porous metal sheet as described above, the structure of the device using the buffer film of this disclosure can be controlled more simply and effectively. The method for measuring the specific resistance is described in the following examples. There are no particular limitations on the method of forming the porous metal sheet to achieve the above specific resistance. Since the inherent specific resistance of metallic materials is known, suitable metals can be selected to form a porous metal sheet with a specific resistance in the above range. To impart heat dissipation characteristics to the porous metal sheet, it is advantageous to select a metal with preferably good thermal conductivity, wherein metals with good thermal conductivity typically exhibit low specific resistance. Therefore, it may be advantageous to use two or more metals to configure the porous metal sheet to simultaneously ensure excellent thermal conductivity and a specific resistance in the above range. In another example, the specific resistance can be 1.1 × 10⁻⁶. -5 Ωcm or larger, 1.2 × 10 -5 Ωcm or larger, 1.3 × 10 -5 Ωcm or larger, 1.4 × 10 -5 Ωcm or larger, 1.5 × 10 -5 Ωcm or larger, 1.6 × 10 -5 Ωcm or larger, 1.7 × 10 -5 Ωcm or larger, 1.8 × 10 -5 Ωcm or larger, 1.9 × 10 -5 Ωcm or larger, 2.0 × 10 -5 Ωcm or larger, 2.1 × 10 -5 Ωcm or larger, or 2.2 × 10 -5 Ωcm or larger, or even 9×10 -5 Ωcm or smaller, 8×10 -5 Ωcm or smaller, 7×10 -5 Ωcm or smaller, 6×10 -5 Ωcm or smaller, 5×10 -5 Ωcm or smaller, 4×10 -5 Ωcm or smaller, 3×10 -5 Ωcm or smaller, 2×10 -5 Ωcm or less, or 1.5 × 10 -5 Ωcm or smaller.

[0033] The thermal diffusivity of the porous metal sheet can be 25 mm. 2 / second or greater. Thermal diffusivity is a value measured in the manner described in the embodiments of this specification. When the porous metal sheet has a thermal diffusivity within the above range, the buffer film of this disclosure can exhibit heat dissipation characteristics in devices such as OLEDs. In another example, the thermal diffusivity can be 30 mm². 2 / second or greater, 35mm 2 / second or greater, 40mm 2 / second or greater, 45mm 2 / second or greater, 50mm 2 / second or greater, 55mm 2 / second or greater, 60mm 2 / second or greater, 65mm 2 / second or greater, 70mm 2 / second or greater, 75mm 2 / second or greater, 80mm 2 / second or greater, 85mm 2 / second or greater, 90mm 2 / second or greater, 95mm 2 / second or greater, 100mm 2 / second or greater, 105mm 2 / second or greater, 110mm 2 / second or greater, 115mm 2 / second or greater, 120mm 2 / second or greater, 125mm 2 / second or greater, 130mm 2 / second or greater, 135mm 2 / second or greater, 140mm 2 / second or greater, 145mm 2 / second or greater, 150mm 2 / second or greater, 155mm 2 / second or greater, 160mm 2 / second or greater, 165mm 2 / second or greater, 170mm 2 / second or greater, 175mm 2 / second or greater, 180mm 2 / second or greater, 185mm 2 / second or greater, 190mm 2 / second or greater, 195mm 2 / second or greater, 200mm 2 / second or greater, 205mm 2 / second or greater, 210mm 2 / second or greater, 215mm 2 / second or greater, 220mm2 / second or greater, 225mm 2 / second or greater, 230mm 2 / second or greater, 235mm 2 / second or greater, 240mm 2 / second or greater, 245mm 2 / second or greater, 250mm 2 / second or greater, 255mm 2 / second or greater, 260mm 2 / second or greater, 265mm 2 / second or greater, 270mm 2 / second or greater, 275mm 2 / second or greater, 280mm 2 / second or greater, 285mm 2 / second or greater, 290mm 2 / second or greater, or 295mm 2 / second or more, or even 300mm 2 / second or less, 295mm 2 / second or less, 290mm 2 / second or less, 285mm 2 / second or less, 280mm 2 / second or less, 275mm 2 / second or less, 270mm 2 / second or less, 265mm 2 / second or less, 260mm 2 / second or less, 255mm 2 / second or less, 250mm 2 / second or less, 245mm 2 / second or less, 240mm 2 / second or less, 235mm 2 / second or less, 230mm 2 / second or less, 225mm 2 / second or less, 220mm 2 / second or less, 215mm 2 / second or less, 210mm 2 / second or less, 205mm 2 / second or less, 200mm 2 / second or less, 195mm 2 / second or less, 190mm 2 / second or less, 185mm 2 / second or less, 180mm 2 / second or less, 175mm2 / second or less, 170mm 2 / second or less, 165mm 2 / second or less, 160mm 2 / second or less, 155mm 2 / second or less, 150mm 2 / second or less, 145mm 2 / second or less, 140mm 2 / second or less, 135mm 2 / second or less, 130mm 2 / second or less, 125mm 2 / second or less, 120mm 2 / second or less, 115mm 2 / second or less, 110mm 2 / second or less, 105mm 2 / second or less, 100mm 2 / second or less, 95mm 2 / second or less, 90mm 2 / second or less, 85mm 2 / second or less, 80mm 2 / second or less, 75mm 2 / second or less, 70mm 2 / second or less, 65mm 2 / second or less, 60mm 2 / second or less, 55mm 2 / second or less, 50mm 2 / second or less, 45mm 2 / second or less, or 40mm 2 / second or less.

[0034] Such thermal diffusivity can be achieved by using porous metal sheets with appropriate metallic materials, taking into account the thermal conductivity of each material's metallic properties. To simultaneously achieve the aforementioned reflectivity, thermal conductivity, and resistivity, porous metal sheets can be configured using two or more metals, as described below.

[0035] As described above, the porous metal sheet included in the buffer membrane is in the form of a membrane, sheet, or layer. A porous metal sheet in such a form may have a first primary surface and a second primary surface opposite to it. Here, among the surfaces defined in the porous metal sheet in the form of a membrane, sheet, or layer, the first primary surface and the second primary surface are two surfaces with a larger area compared to the other surfaces, and such first and second primary surfaces are generally opposite each other.

[0036] The first and second principal surfaces can have different surface roughnesses. By changing the surface roughness of the first and second principal surfaces of the porous metal sheet, the buffering characteristics and durability of the device can be further improved. For example, when the buffer film of this disclosure is applied to an OLED, the buffer film can be applied to the surface of the substrate opposite to the surface on which the organic light-emitting layer is formed, as described below. In this case, when the buffer film is configured such that the surface with a larger surface roughness (in the following, it is assumed that the first principal surface has a larger surface roughness) of the first and second principal surfaces of the porous metal sheet faces the organic light-emitting layer, a better shock mitigation effect can be obtained. Although not theoretically limited, the reason for obtaining this effect is estimated as follows. Typically, the shock to be mitigated in the shock applied to the OLED is an shock applied in the direction from the organic light-emitting layer to the substrate. Therefore, when the buffer film is configured such that the first principal surface of the first and second principal surfaces faces the organic light-emitting layer, the shock is first applied to the first principal surface of the first and second principal surfaces, and the applied shock is transmitted in the direction from the first principal surface to the second principal surface. At this point, if the surface roughness of the first primary surface to which the impact is first applied is large, the impact can be effectively absorbed compared to the case where the surface roughness is small. Furthermore, the applied impact is transmitted to the second primary surface and then dispersed, wherein if the second primary surface on which the impact is dispersed exhibits relatively small surface roughness, the impact can be dispersed more effectively.

[0037] Furthermore, to arrange the buffer film as described above, an adhesive layer, as described below, is attached to the porous metal sheet, wherein the adhesive layer is formed on a first major surface with a large surface roughness for arranging such a buffer film. Here, because the first major surface has a large surface roughness, better adhesion to the adhesive layer can be achieved through the so-called anchoring effect, thus improving the device's durability.

[0038] There is no particular limitation on the difference in surface roughness between the first primary surface and the second primary surface. However, in order to properly ensure the above effect, the ratio of the surface roughness 1Sa of the first primary surface to the surface roughness (2Sa) of the second primary surface, 1Sa / 2Sa, can be adjusted to be greater than 1 and 3 or less. In another instance, the ratio 1Sa / 2Sa can be 1.05 or greater, 1.1 or greater, 1.15 or greater, 1.2 or greater, 1.25 or greater, 1.3 or greater, 1.35 or greater, 1.4 or greater, 1.45 or greater, 1.5 or greater, 1.55 or greater, 1.6 or greater, 1.65 or greater, or 1.7 or greater, or it can also be 2.9 or less, 2.8 or less, 2.7 or less, 2.6 or less, 2.5 or less, 2.4 or less, 2.3 or less, 2.2 or less, 2.1 or less, 2.0 or less, 1.9 or less, 1.8 or less, 1.7 or less, 1.6 or less, 1.5 or less, 1.4 or less, 1.3 or less, or around 1.2 or less.

[0039] At this ratio, the surface roughness 1Sa of the first primary surface can be 6.5 μm or greater. In another example, the surface roughness 1Sa can be 6.7 μm or greater, 6.9 μm or greater, 7.1 μm or greater, 7.3 μm or greater, 7.5 μm or greater, 7.7 μm or greater, 7.9 μm or greater, 8.1 μm or greater, 8.3 μm or greater, 8.5 μm or greater, or around 8.7 μm or greater, or it can also be 20 μm or less, 18 μm or less, 16 μm or less, 14 μm or less, 12 μm or less, 10 μm or less, or around 8 μm or less.

[0040] The method for measuring the surface roughness of the first and second principal surfaces is described in the Examples section.

[0041] There are no particular limitations on the methods used to control the surface roughness of the two surfaces of the porous metal sheet as described above. As described below, in this disclosure, metal foam, sintered metal fiber sheets, or metal meshes can be used as porous metal sheets. Here, metal foam can be prepared by using a slurry containing metal powder to prepare a precursor and then sintering it. For example, in the above process, the surface roughness can be controlled by adjusting the particle size of the metal powder in the slurry. Furthermore, in sintered metal fiber sheets, the surface roughness can also be controlled by controlling the wire diameter of the applied metal fibers, and in the case of metal meshes, the surface roughness can be adjusted by controlling the mesh size, etc. Furthermore, there are no particular limitations on the methods for changing the surface roughness of the first and second main surfaces. During the manufacture of metal foam or sintered metal fiber sheets in porous metal sheets, a sintering process for the precursor can be performed. At this time, the precursor can also be in the form of a film, sheet, or layer. During the sintering process, one main surface of the film, sheet, or layer contacts a relatively smooth surface and is sintered while the opposing surface is exposed to air, or sintered while the opposing surface is in contact with a surface with roughness, thereby obtaining a porous metal sheet with different surface roughnesses on the two main surfaces. Furthermore, if it is necessary to adjust the surface roughness of the main surfaces of the manufactured porous metal sheet without using the above method, the surface roughness of the porous metal sheet can be adjusted by applying a method such as extruding the surface of the porous metal sheet.

[0042] The porous metal sheet of the buffer membrane disclosed herein can have electromagnetic wave shielding capability. In metals, conductive metals can exhibit electromagnetic wave reflection characteristics. Therefore, electromagnetic waves propagating to the buffer membrane can be reflected and shielded by the porous metal sheet. Furthermore, since the porous metal sheet includes gaps within or on its surface, electromagnetic waves that have propagated to the porous metal sheet can be repeatedly reflected within these gaps, and the electromagnetic waves can dissipate in this process through interference or the like.

[0043] In one example, the electromagnetic shielding characteristic of the porous metal sheet in the range of 30 MHz to 1.5 GHz can be 70 dB or greater. In another example, the electromagnetic shielding characteristic can be 75 dB or greater, 80 dB or greater, 85 dB or greater, 86 dB or greater, 87 dB or greater, 88 dB or greater, 89 dB or greater, 90 dB or greater, 91 dB or greater, 92 dB or greater, 93 dB or greater, 94 dB or greater, or 95 dB or greater. There is no particular upper limit to the electromagnetic shielding characteristic, but for example, it can be about 200 dB or less, 190 dB or less, 180 dB or less, 170 dB or less, 160 dB or less, 150 dB or less, 140 dB or less, 130 dB or less, 120 dB or less, 100 dB or less, or around 100 dB or less. Such electromagnetic shielding properties can be achieved by adjusting the porosity, thickness, and material of the porous metal sheet. Electromagnetic shielding properties can be measured according to ASTM D4935 or ASTM ES7 standards.

[0044] To ensure the required impact resistance and achieve the aforementioned electromagnetic wave shielding and heat dissipation characteristics, the thickness of the porous metal sheet can be controlled. For example, the thickness of the porous metal sheet can be 50 μm or greater, 65 μm or greater, 70 μm or greater, 75 μm or greater, 80 μm or greater, 85 μm or greater, 90 μm or greater, 95 μm or greater, 100 μm or greater, 105 μm or greater, 110 μm or greater, 115 μm or greater, 120 μm or greater, 125 μm or greater, 130 μm or greater, 135 μm or greater, 140 μm or greater, 145 μm or greater, 150 μm or greater, 155 μm or greater, 160 μm or greater, 165 μm or greater, 170 μm or greater, 175 μm or greater, 180 μm or greater, 185 μm or greater, 190 μm or greater, 195 μm or greater, or around 200 μm or greater. Increasing the thickness of porous metal sheets is advantageous in ensuring the heat dissipation, electromagnetic shielding, and shock resistance required for OLEDs, so there is no particular upper limit to this thickness. However, when the porous metal sheet is too thick, it is not conducive to achieving thin devices. Therefore, the thickness of the porous metal sheet can be controlled within the range of approximately 1000 μm or less, 900 μm or less, 800 μm or less, 700 μm or less, 600 μm or less, 500 μm or less, 400 μm or less, 300 μm or less, 200 μm or less, or 150 μm or less.

[0045] Porous metal sheets can be formed using various known metals or metal alloys. Considering the reflectivity, thermal conductivity, and electrical conductivity of metallic materials, porous metal sheets exhibiting these properties can be obtained by selecting appropriate materials.

[0046] For example, the porous metal sheet may contain any one of the metals selected from stainless steel, copper, gold, platinum, silver, aluminum, nickel, manganese, iron, cobalt, magnesium, molybdenum, tungsten, and zinc, or two or more of the aforementioned, or may be composed of, but is not limited to, these metals.

[0047] In the porous metal sheet, based on the total weight of the porous metal sheet, the content of any one of the metals selected from stainless steel, copper, gold, platinum, silver, aluminum, nickel, manganese, iron, cobalt, magnesium, molybdenum, tungsten, and zinc, or two or more of the aforementioned, can be approximately 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, or 95% by weight or more. Since the porous metal sheet can contain only metal, the upper limit for the weight percentage of metal is 100% by weight.

[0048] In one instance, the porous metal sheet may contain a first metal and a second metal different from the first metal.

[0049] In one instance, the first metal and the second metal can have Young's modulus in different ranges.

[0050] For example, the Young's modulus of the first metal can be 160 GPa or less, and the Young's modulus of the second metal can be greater than 160 GPa. The Young's modulus of the metals is a value determined according to ASTM E111.

[0051] In another example, the Young's modulus of the first metal can be around 155 GPa or less, 150 GPa or less, 145 GPa or less, 140 GPa or less, 135 GPa or less, 130 GPa or less, 125 GPa or less, 120 GPa or less, or 115 GPa or less, or it can also be around 50 GPa or greater, 55 GPa or greater, 60 GPa or greater, 65 GPa or greater, 70 GPa or greater, 75 GPa or greater, 80 GPa or greater, 85 GPa or greater, 90 GPa or greater, 95 GPa or greater, 100 GPa or greater, 105 GPa or greater, 110 GPa or greater, 115 GPa or greater, 120 GPa or greater, or around 125 GPa or greater.

[0052] In another example, the Young's modulus of the second metal can be 165 GPa or greater, 170 GPa or greater, 175 GPa or greater, 180 GPa or greater, 185 GPa or greater, 190 GPa or greater, 195 GPa or greater, or around 200 GPa or greater, or it can also be 400 GPa or less, 395 GPa or less, 390 GPa or less, 385 GPa or less, 380 GPa or less, 375 GPa or less, 370 GPa or less, 365 GPa or less, 360 GPa or less, 355 GPa or less, 350 GPa or less, 345 GPa or less, 340 GPa or less, 335 GPa or less, 330 GPa or less. Smaller, 325 GPa or smaller, 320 GPa or smaller, 315 GPa or smaller, 310 GPa or smaller, 305 GPa or smaller, 300 GPa or smaller, 295 GPa or smaller, 290 GPa or smaller, 285 GPa or smaller, 280 GPa or smaller, 275 GPa or smaller, 270 GPa or smaller, 265 GPa or smaller, 260 GPa or smaller, 255 GPa or smaller, 250 GPa or smaller, 245 GPa or smaller, 240 GPa or smaller, 235 GPa or smaller, 230 GPa or smaller, 225 GPa or smaller, 220 GPa or smaller, 215 GPa or smaller, 210 GPa or smaller, or around 205 GPa or smaller.

[0053] By applying a first metal and a second metal, each having the above Young's modulus, a porous metal sheet can be obtained in which the desired impact mitigation properties are effectively ensured.

[0054] In one instance, the first metal and the second metal can have different ranges of specific resistance.

[0055] For example, the resistivity of the first metal can be 4.3 × 10⁻⁶. -6 Ωcm or less, and the resistivity of the second metal can be greater than 4.3 × 10⁻⁶. -6 Ωcm. The resistivity of a metal is a value determined according to ASTM E1004-17.

[0056] In another example, the resistivity of the first metal can be 4.1 × 10⁻⁶. -6 Ωcm or smaller, 3.9 × 10 -6 Ωcm or smaller, 3.7 × 10 -6 Ωcm or smaller, 3.5 × 10 -6 Ωcm or smaller, 3.3 × 10 -6 Ωcm or smaller, 3.1 × 10 -6 Ωcm or smaller, 2.9 × 10 -6Ωcm or smaller, 2.7 × 10 -6 Ωcm or smaller, 2.5 × 10 -6 Ωcm or smaller, 2.3 × 10 -6 Ωcm or smaller, 2.1 × 10 -6 Ωcm or smaller, 1.9 × 10 -6 Ωcm or smaller, or 1.7 × 10 -6 Ωcm or smaller, or even 0.5 × 10⁻⁶. -6 Ωcm or larger, 0.7 × 10 -6 Ωcm or larger, 0.9 × 10 -6 Ωcm or larger, 1.0 × 10 -6 Ωcm or larger, 1.1 × 10 -6 Ωcm or larger, 1.3 × 10 -6 Ωcm or larger, 1.5 × 10 -6 Ωcm or larger, or 1.7 × 10 -6 Ωcm or larger.

[0057] In another example, the resistivity of the second metal can be 4.5 × 10⁻⁶. -6 Ωcm or larger, 4.9 × 10 -6 Ωcm or larger, 5.1 × 10 -6 Ωcm or larger, 5.3 × 10 -6 Ωcm or larger, 5.5 × 10 -6 Ωcm or larger, 5.7 × 10 -6 Ωcm or larger, 5.9 × 10 -6 Ωcm or larger, 6.1 × 10 -6 Ωcm or larger, 6.3 × 10 -6 Ωcm or larger, 6.5 × 10 -6 Ωcm or larger, 6.7 × 10 -6 Ωcm or larger, or 6.9 × 10 -6 Ωcm or larger, or even 15×10 -6 Ωcm or smaller, 14×10 -6 Ωcm or smaller, 13×10 -6 Ωcm or smaller, 12×10 -6 Ωcm or smaller, 11×10 -6 Ωcm or smaller, 10×10 -6 Ωcm or smaller, 9.9 × 10 -6 Ωcm or smaller, 9.7 × 10 -6 Ωcm or smaller, 9.5 × 10 -6 Ωcm or smaller, 9.3 × 10 -6Ωcm or smaller, 9.1 × 10 -6 Ωcm or smaller, 8.9 × 10 -6 Ωcm or smaller, 8.7 × 10 -6 Ωcm or smaller, 8.5 × 10 -6 Ωcm or smaller, 8.3 × 10 -6 Ωcm or smaller, 8.1 × 10 -6 Ωcm or smaller, 7.9 × 10 -6 Ωcm or smaller, 7.7 × 10 -6 Ωcm or smaller, 7.5 × 10 -6 Ωcm or smaller, 7.3 × 10 -6 Ωcm or smaller, 7.1 × 10 -6 Ωcm or smaller, or 6.9 × 10 -6 Ωcm or smaller.

[0058] By applying a first metal and a second metal, each having a specific resistivity within such a range, porous metal sheets that simultaneously possess the desired thermal conductivity and resistivity can be formed more effectively.

[0059] In one instance, the first metal and the second metal can have different ranges of thermal conductivity.

[0060] For example, the thermal conductivity of the first metal can be 150 W / mK or greater, and the thermal conductivity of the second metal can be less than 150 W / mK. The thermal conductivity of the metals is a value determined according to ASTM E1225.

[0061] In another example, the thermal conductivity of the first metal can be 1000 W / mK or less, 950 W / mK or less, 900 W / mK or less, 850 W / mK or less, 800 W / mK or less, 750 W / mK or less, 700 W / mK or less, 650 W / mK or less, 600 W / mK or less, 550 W / mK or less, 500 W / mK or less, or around 450 W / mK or less, or it can also be 160 W / mK or greater, 170 W / mK or greater, 180 W / mK or greater, 190 W / mK or greater, 200 W / mK or greater, 210 W / mK or greater. W / mK or greater, 220W / mK or greater, 230W / mK or greater, 240W / mK or greater, 250W / mK or greater, 260W / mK or greater, 270W / mK or greater, 280W / mK or greater, 290W / mK or greater, 300W / mK or greater, 310W / mK or greater, 320W / mK or greater, 330W / mK or greater, 340W / mK or greater, 350W / mK or greater, 360W / mK or greater, 370W / mK or greater, 380W / mK or greater, 390W / mK or greater, or around 400W / mK or greater.

[0062] In another example, the thermal conductivity of the second metal can be around 10 W / mK or greater, 20 W / mK or greater, 30 W / mK or greater, 40 W / mK or greater, 50 W / mK or greater, 60 W / mK or greater, 70 W / mK or greater, 80 W / mK or greater, or 90 W / mK or greater, or it can also be around 145 W / mK or less, 140 W / mK or less, 135 W / mK or less, 130 W / mK or less, 125 W / mK or less, 120 W / mK or less, 115 W / mK or less, 110 W / mK or less, 105 W / mK or less, 100 W / mK or less, or 95 W / mK or less.

[0063] By applying a first metal and a second metal, each having thermal conductivity within such a range, porous metal sheets that simultaneously possess the desired thermal conductivity and electrical resistance properties can be formed more effectively.

[0064] The first metal may exhibit at least one property selected from Young's modulus, thermal conductivity, and resistivity, and in one instance, it may exhibit Young's modulus, thermal conductivity, and resistivity simultaneously. There are no particular limitations on the type of such metal; for example, the first metal may be copper.

[0065] The second metal may exhibit at least one property selected from Young's modulus, thermal conductivity, and resistivity, and in one instance, it may exhibit Young's modulus, thermal conductivity, and resistivity simultaneously. There are no particular limitations on the type of such metal; for example, the second metal may be copper.

[0066] Furthermore, a porous metal sheet may contain only one type of first metal, and it may also contain two or more types of first metal. For example, even if there are two or more types of metals that have Young's moduli within the aforementioned range but are of different types, these two or more types of metals are considered as the first metal, provided that their Young's moduli are within the aforementioned range. This classification applies to resistivity or thermal conductivity.

[0067] A porous metal sheet may contain only one type of second metal, and it may also contain two or more types of second metals. For example, even if there are two or more types of metals with Young's moduli within the aforementioned range but different from each other, these two or more types of metals are considered second metals, provided that their Young's moduli are within the aforementioned range. This classification applies to resistivity or thermal conductivity.

[0068] Based on the total weight of the porous metal sheet, the total weight ratio of the first metal and the second metal in the porous metal sheet can be approximately 55% by weight or more, 60% by weight or more, 65% by weight or more, 70% by weight or more, 75% by weight or more, 80% by weight or more, 85% by weight or more, 90% by weight or more, or 95% by weight or more. Since the porous metal sheet can contain only the first metal and the second metal, the upper limit for the total weight ratio of the first metal and the second metal is 100% by weight.

[0069] The first and second metals can have different thermal conductivity, resistivity, and / or Young's modulus as described above, and simultaneously exhibit densities within a similar range. The density of the metals is a value determined according to ASTM B923.

[0070] For example, the densities of the first and second metals can each be 6 g / cm³. 3 Up to 15g / cm 3 Within a certain range. In another example, the density could be 6.5 g / cm³. 3 or larger, 7g / cm 3 Or larger, 7.5g / cm 3 or larger, 8g / cm 3 Or larger, or 8.5g / cm 3 Or even larger, or perhaps as high as 14.5 g / cm³. 3 or smaller, 14g / cm 3or smaller, 13.5g / cm 3 or smaller, 13g / cm 3 Or smaller, 12.5g / cm 3 or smaller, 12g / cm 3 or smaller, 11.5g / cm 3 or smaller, 11g / cm 3 or smaller, 10.5g / cm 3 Or smaller, or 10g / cm 3 Or even smaller.

[0071] By using metals with densities within this range, it is possible to manufacture lighter buffer membranes that still ensure the desired effect.

[0072] The first and second metals can have different thermal conductivity, resistivity, and / or Young's modulus as described above, and simultaneously exhibit Poisson's ratios within similar ranges. The Poisson's ratio of the metals is a value determined according to ASTM E132.

[0073] For example, the Poisson's ratios of the first and second metals can each be in the range of 0.1 to 0.7. In another example, the Poisson's ratio can be about 0.15 or greater, 0.2 or greater, 0.25 or greater, or 0.3 or greater, or it can also be about 0.65 or less, 0.6 or less, 0.55 or less, 0.5 or less, 0.45 or less, 0.4 or less, or 0.35 or less.

[0074] By applying metals with Poisson's ratios within such a range, it is possible to more effectively manufacture buffer membranes that exhibit the desired shock-absorbing effects.

[0075] The first metal and the second metal can each independently satisfy one or both of the above-mentioned density and Poisson's ratio.

[0076] There is no particular limitation on the ratio of the first metal to the second metal in the porous metal sheet. That is, since the above-mentioned reflectivity, resistivity and thermal conductivity characteristics of the porous metal sheet depend on the content of the first metal and the second metal, the content ratio of the first metal to the second metal can be adjusted to meet the above-mentioned reflectivity, resistivity and thermal conductivity characteristics.

[0077] There are no limitations on the method of simultaneously including a first metal and a second metal in a porous metal sheet. For example, as described below, the porous metal sheet can be a metal foam, a sintered metal fiber sheet, or a metal mesh, wherein the first metal and the second metal can be used simultaneously as materials for the metal foam, sintered metal fiber sheet, or metal mesh. Alternatively, a method can be applied to form a metal foam, sintered metal fiber sheet, or metal mesh from either the first metal or the second metal, and then form a metal layer from another metal on the metal foam, sintered metal fiber sheet, or metal mesh. Here, there are no particular limitations on the method of forming the metal layer; for example, known methods such as electroplating or electroless plating can be used.

[0078] In one instance, the porous metal sheet can be a so-called metal foam. Known metal foams can be used without particular restriction, as long as they are made of the aforementioned materials and exhibit the aforementioned properties (resistivity, thermal conductivity, reflectivity, etc.).

[0079] These metal foams are widely known, and methods for manufacturing metal foams are also widely known. This disclosure may apply to such known metal foams or metal foams manufactured by known methods.

[0080] The metal foam used in this disclosure can be formed, for example, by a method including the step of sintering a metal foam precursor containing the aforementioned metal. In this disclosure, the term metal foam precursor refers to a structure prior to a process performed to form a metal foam, such as sintering, i.e., a structure prior to the formation of a metal foam. Even if a metal foam precursor is called a porous metal foam precursor, it is not necessarily porous itself, as long as it can ultimately be formed into a metal foam with a porous metal structure; for convenience, it can be referred to as a porous metal foam precursor.

[0081] Metal foam precursors can be formed using a slurry containing at least a metal component, a dispersant or solvent, and a binder, wherein the application of the slurry can effectively produce porous metal sheets with desired properties.

[0082] Metal powders can be used as the metal component. Examples of suitable metal powders are determined according to the purpose and are not particularly limited. For example, powders of the first metal and / or the second metal, or powders of metal alloys or powders of metal mixtures as described above can be used.

[0083] The size of the metal powder is also selected considering desired porosity or surface roughness, and there are no particular limitations. However, for example, the average particle size of the metal powder can range from about 0.1 μm to about 200 μm. In another example, the average particle size can be about 0.5 μm or greater, about 1 μm or greater, about 2 μm or greater, about 3 μm or greater, about 4 μm or greater, about 5 μm or greater, about 6 μm or greater, about 7 μm or greater, or about 8 μm or greater, 10 μm or greater, 15 μm or greater, 20 μm or greater, 25 μm or greater, 30 μm or greater, 35 μm or greater, 40 μm or greater, 45 μm or greater, 50 μm or greater, or 55 μm or greater. In another example, the average particle size can be approximately 150 μm or less, 100 μm or less, 90 μm or less, 80 μm or less, 70 μm or less, 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, or 20 μm or less. For metals within metal particles, those with different average particle sizes can also be applied. The average particle size can be selected within an appropriate range, taking into account the desired shape of the metal foam (e.g., the thickness or porosity of the metal foam, etc.). The average particle size of the metal powder mentioned in this specification is the so-called median particle size, also known as the D50 particle size. Such a median particle size can be obtained using known particle size analysis methods.

[0084] The proportion of metal components (metal powder) in the slurry is not particularly limited and can be selected considering factors such as desired viscosity or process efficiency. In one example, the proportion of metal components in the slurry, by weight, can range from approximately 0.5% to about 95%, but is not limited to this. In another example, the proportion can be approximately 1% or greater, approximately 1.5% or greater, approximately 2% or greater, approximately 2.5% or greater, approximately 3% or greater, approximately 5% or greater, 10% or greater, 15% or greater, 20% or greater, 25% or greater, 30% or greater, 35% or greater, 40% or greater, 45% or greater, 50% or greater, 55% or greater, 60% or greater, 65% or greater, 70% or greater, 75% or greater. Large, or 80% or more, or may be about 90% or less, about 85% or less, about 80% or less, about 75% or less, about 70% or less, about 65% or less, 60% or less, 55% or less, 50% or less, 45% or less, 40% or less, 35% or less, 30% or less, 25% or less, 20% or less, 15% or less, 10% or less, or about 5% or less, but not limited to these.

[0085] Metal foam precursors can be formed using a slurry containing dispersants or solvents and binders, as well as metal powder.

[0086] Alcohols can be used as dispersants or solvents, for example. Monohydric alcohols having 1 to 20 carbon atoms, such as methanol, ethanol, propanol, pentanol, octanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, or terpineol, can be used; or dihydric alcohols having 1 to 20 carbon atoms, such as ethylene glycol, propylene glycol, hexanediol, octanediol, or pentanediol; or higher polyhydric alcohols having 1 to 20 carbon atoms, such as glycerol or texanol; and so on, but the types are not limited to the above. Furthermore, suitable solvents can be used as other solvents, taking into account the solubility of the metal component and the binder described below, wherein solvents with dielectric constants in the range of about 10 to 120 can be used. In another example, the dielectric constant can be about 20 or greater, about 30 or greater, about 40 or greater, about 50 or greater, about 60 or greater, or about 70 or greater, or about 110 or less, about 100 or less, or about 90 or less. Such solvents may be exemplified as water or alcohols having 1 to 8 carbon atoms, such as ethanol, butanol or methanol, DMSO (dimethyl sulfoxide), DMF (dimethylformamide) or NMP (N-methylpyrrolidone), or ester-based solvents such as alkyl isobutyrate esters having alkyl groups having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms, such as IBIB (isobutyl isobutyrate), but are not limited thereto.

[0087] A mixture of alcohol and ester-based solvent can also be used as a solvent or dispersant. In this case, for example, about 1 to 100 parts by weight of ester-based solvent can be used relative to 100 parts by weight of alcohol. In another example, the ratio of ester-based solvent can be 3 parts by weight or more, 5 parts by weight or more, 7 parts by weight or more, 9 parts by weight or more, or 11 parts by weight or more, or it can be about 90 parts by weight or less, 80 parts by weight or less, 70 parts by weight or less, 60 parts by weight or less, 50 parts by weight or less, 40 parts by weight or less, 30 parts by weight or less, or about 20 parts by weight or less.

[0088] The slurry may also contain a binder. There are no particular limitations on the type of such binder, which may be appropriately selected based on the type of metal component, solvent, or dispersant used in the production of the slurry. Examples of binders include alkyl celluloses having alkyl groups containing 1 to 8 carbon atoms, such as methyl cellulose or ethyl cellulose; polyalkylene carbonates having alkylene units containing 1 to 8 carbon atoms, such as polypropylene carbonate or polyethylene carbonate; or polyvinyl alcohol-based binders, such as polyvinyl alcohol or polyvinyl acetate (hereinafter also referred to as polyvinyl alcohol compounds), etc., but not limited to these.

[0089] There are no particular restrictions on the ratio of the components in the slurry. Such ratios can be adjusted by taking into account process efficiency, such as coating characteristics and formability, when using the slurry in a process.

[0090] For example, relative to 100 parts by weight of the aforementioned metal component, the binder can be included in the slurry at a ratio of about 1 part by weight to 500 parts by weight to more effectively ensure pore properties such as desired porosity or surface roughness. In another example, this ratio can be about 2 parts by weight or more, about 3 parts by weight or more, about 4 parts by weight or more, about 5 parts by weight or more, about 6 parts by weight or more, about 7 parts by weight or more, about 8 parts by weight or more, about 9 parts by weight or more, about 10 parts by weight or more, about 20 parts by weight or more, about 30 parts by weight or more, about 40 parts by weight or more, about 50 parts by weight or more, about 60 parts by weight or more, about 70 parts by weight or more, about 80 parts by weight or more, about 90 parts by weight or more, about 100 parts by weight or more, about 110 parts by weight or more, about 120 parts by weight or more, or about 130 parts by weight. It may be approximately 140 parts by weight or more, approximately 150 parts by weight or more, approximately 200 parts by weight or more, or approximately 250 parts by weight or more, and may also be approximately 450 parts by weight or less, approximately 400 parts by weight or less, approximately 350 parts by weight or less, approximately 300 parts by weight or less, approximately 250 parts by weight or less, approximately 200 parts by weight or less, approximately 150 parts by weight or less, approximately 100 parts by weight or less, approximately 50 parts by weight or less, approximately 40 parts by weight or less, approximately 30 parts by weight or less, approximately 20 parts by weight or less, approximately 10 parts by weight or less, approximately 8 parts by weight or less, or approximately 6 parts by weight or less.

[0091] Relative to 100 parts by weight of binder, the dispersant or solvent in the slurry can be included in a ratio of about 0.5 parts by weight to 2,000 parts by weight to more effectively ensure desired pore properties, etc. In another example, this ratio can be about 1 part by weight or more, about 1.5 parts by weight or more, about 5 parts by weight or more, about 10 parts by weight or more, about 15 parts by weight or more, about 20 parts by weight or more, about 30 parts by weight or more, about 40 parts by weight or more, about 50 parts by weight or more, about 60 parts by weight or more, about 70 parts by weight or more, about 80 parts by weight or more, about 90 parts by weight or more, about 100 parts by weight or more, about 200 parts by weight or more, about 300 parts by weight or more, about 400 parts by weight or more, about 500 parts by weight or more, about 550 parts by weight or more, about 600 parts by weight or more, or about 650 parts by weight or more, and can be about 180 parts by weight or more. 0 parts by weight or less, about 1,600 parts by weight or less, about 1,400 parts by weight or less, 1,200 parts by weight or less, or about 1,000 parts by weight or less, about 900 parts by weight or less, about 800 parts by weight or less, about 700 parts by weight or less, about 600 parts by weight or less, about 500 parts by weight or less, about 400 parts by weight or less, about 300 parts by weight or less, about 200 parts by weight or less, about 150 parts by weight or less, about 130 parts by weight or less, about 110 parts by weight or less, about 100 parts by weight or less, about 50 parts by weight or less, about 30 parts by weight or less, about 20 parts by weight or less, about 10 parts by weight or less, or about 5 parts by weight or less.

[0092] Unless otherwise stated, parts by weight in this document refer to the weight ratio between the components.

[0093] In addition to the components mentioned above, the slurry may also contain necessary known additives. However, in order to effectively obtain desired pore properties or surface roughness, the slurry may not contain a so-called foaming agent. The term foaming agent includes components that can exhibit a foaming effect relative to other components in the slurry, as well as other components commonly referred to as foaming agents in industry. Therefore, in this disclosure, a foaming process may not be performed during the manufacture of metal foam.

[0094] The types of other components that can be included in the slurry vary, but a representative example can be illustrated by polymer beads as pore-forming agents. These polymer beads are present in the slurry and then, while being removed during processes such as sintering, form pores in the regions present in the slurry. There are no particular limitations on the types of polymer beads that can be used, wherein beads that can be removed during sintering (e.g., polymer beads with a sintering temperature or a lower melting point) and have an average particle size suitable for the desired pore size can be used.

[0095] In addition, the slurry may further contain additives known to function as so-called leveling agents.

[0096] There are no particular limitations on the method of forming metal foam precursors using slurry. Various methods for forming metal foam precursors are known in the field of metal foam manufacturing, and all of these methods can be applied in this disclosure. For example, metal foam precursors can be formed by holding the slurry in a suitable template or by coating the slurry in an appropriate manner.

[0097] When producing metal foam in the form of a film or sheet according to an example of this disclosure, applying a coating method may be advantageous. For example, after coating a slurry onto a suitable substrate to form a precursor, the desired metal foam can be formed by a sintering process described below. In the above process, the surface roughness of the metal foam can also be controlled by controlling the smoothness of the surface of the substrate on which the slurry is coated.

[0098] The form of the metal foam precursor is determined by the desired metal foam and is not particularly limited. In one instance, the metal foam precursor may be in the form of a film, sheet, or layer, as in the case of a porous metal sheet.

[0099] During the formation of the metal foam precursor, a suitable drying process can also be performed. For example, the metal foam precursor can also be formed by shaping a slurry via the coating method described above, and then drying it for a certain period of time. The drying conditions are not particularly limited and can be controlled to, for example, to remove the solvent contained in the slurry to a desired level. For example, the shaped slurry can be dried by maintaining it at a temperature in the range of approximately 50°C to 250°C, approximately 70°C to 180°C, or approximately 90°C to 150°C for an appropriate period of time. The drying time can also be selected within an appropriate range.

[0100] The metal foam precursor formed in this manner can be sintered to produce metal foam. In this case, there are no particular limitations on the method of sintering for producing metal foam, and known sintering methods can be applied. That is, sintering can be carried out by applying an appropriate amount of heat to the metal foam precursor in a suitable manner.

[0101] In this case, taking into account the state of the metal foam precursor used (e.g., the composition of the slurry or the type of metal powder), the sintering conditions can be controlled to allow the metal powders to connect and form a porous structure, and there are no particular restrictions on the specific conditions.

[0102] For example, the precursor can be sintered by maintaining a temperature in the range of approximately 500°C to 2000°C, 700°C to 1500°C, or 800°C to 1200°C, and the holding time can also be optionally selected. In one example, the holding time can range from approximately 1 minute to approximately 10 hours, but is not limited to this.

[0103] After the metal foam is formed in this way, if necessary, a metal layer forming process, such as electroplating or chemical plating, can be performed to form a porous metal sheet containing a first metal and a second metal.

[0104] To ensure the required shock resistance and achieve electromagnetic shielding and heat dissipation characteristics, the pore properties of the metal foam can be controlled. For example, the porosity of the metal foam can range from 50% to 80%. In another example, the porosity of the metal foam can be 52% or greater, 54% or greater, 56% or greater, 58% or greater, 60% or greater, 62% or greater, 64% or greater, 66% or greater, or 68% or greater, or even around 78% or less, 76% or less, 74% or less, or 72% or less. Such porosity of the metal foam can be obtained using known methods that convert porosity through the volume, mass, density, etc., of the metal foam.

[0105] In another example, the porous metal sheet can be a sintered sheet of metal fibers or a metal mesh layer.

[0106] Metal fiber sintered sheets refer to sheet-like products manufactured by applying metal fibers to papermaking processes or similar methods to form sheet or film shapes, and then sintering them together. Metal mesh refers to sheet-like products manufactured by braiding or weaving metal fibers into grids, wire meshes, nets, or woven fabric shapes.

[0107] The above-mentioned sintered metal fiber sheets and / or metal mesh layers can also be provided as porous metal sheets with desired electromagnetic wave shielding properties, heat dissipation properties and shock absorption properties by individually applying materials, thickness and / or pore control.

[0108] To ensure the required electromagnetic shielding characteristics, shock resistance, and / or heat dissipation characteristics, the wire diameter, porosity, and / or mesh characteristics of the metal fibers constituting the metal fiber sintered sheets and / or metal mesh layers can be controlled.

[0109] Here, the wire diameter of a metal fiber refers to the cross-sectional diameter of the metal fiber. This wire diameter can be the wire diameter of the metal fiber in the state of forming a sintered metal fiber sheet or a metal mesh, or it can be the wire diameter of the metal fiber used as a raw material before being manufactured into a sintered metal fiber sheet or a metal mesh.

[0110] For example, the metal fibers forming the metal fiber sintered sheet or the metal fibers used as raw materials for manufacturing the metal fiber sintered sheet can have a wire diameter in the range of 1 μm to 80 μm.

[0111] Furthermore, in one example, the sintered metal fiber sheet can have a porosity ranging from 40% to 80%. The porosity of the sintered metal fiber sheet can be obtained through known methods of converting porosity via the volume, mass, density, etc., of the sintered metal fiber sheet.

[0112] For example, the metal fibers that form the metal mesh or the metal fibers used as raw materials for manufacturing the metal mesh can have a wire diameter in the range of 25 μm to 100 μm.

[0113] In addition, the metal mesh layer can have a mesh size in the range of 100 to 200 mesh.

[0114] The aforementioned sintered metal fiber sheets and / or metal mesh layers can be configured using any known metallic materials (metal fibers) without any particular limitations. That is, the sintered metal fiber sheets and / or metal mesh layers can be configured by selecting appropriate materials taking into account the Young's modulus, resistivity, thermal conductivity, Poisson's ratio, and / or density of the aforementioned metals.

[0115] Metal fiber sintered sheets and / or metal mesh layers are widely known, and methods for manufacturing metal fiber sintered sheets and / or metal mesh layers are also widely known. In this disclosure, such known metal fiber sintered sheets and / or metal mesh layers, or metal fiber sintered sheets and / or metal mesh layers prepared by known methods, can be applied.

[0116] In order to include the desired first and second metals in the metal fiber sintered sheets and / or metal mesh layers, metal layer forming processes, such as electroplating or electroless plating, may also be performed if necessary.

[0117] The porous metal sheet of the buffer membrane may include only one of metal foam, metal fiber sintered sheet and metal mesh layer, or it may be in the form of a laminate or combination of two or more of the foregoing.

[0118] The buffer membrane, or the porous metal sheet included therein, may be substantially free of organic components, such as polymers. This is important in ensuring desired heat dissipation characteristics or impact resistance. For example, composite materials in which metal foam is combined with organic components such as polymers are known, but such combination increases the thermal conductivity of the metal foam in the thickness direction and reduces its impact resistance. Therefore, in this disclosure, the buffer membrane, or the porous metal sheet included therein, needs to be substantially free of organic components. Here, "substantially free of organic components" means that the ratio of organic components in the buffer membrane or porous metal sheet is about 5% by weight or less, 4.5% by weight or less, 4% by weight or less, 3.5% by weight or less, 3% by weight or less, 2.5% by weight or less, 2% by weight or less, 1.5% by weight or less, 1% by weight or less, or about 0.5% by weight or less. In this case, the ratio of organic components does not include organic components contained in the layers applied to attach the porous metal sheet to the substrate (e.g., the adhesive layer described below). There is no lower limit to the ratio of organic components; since it is necessary to exclude organic components, the lower limit of this ratio can be 0 by weight.

[0119] The buffer film may include an adhesive layer for attaching the porous metal sheet to a substrate or the like as an additional component. The adhesive layer may be formed on one or both sides of the porous metal sheet. As described above, when the porous metal sheet includes a first primary surface and a second primary surface with different surface roughnesses, the adhesive layer may be formed on the primary surface having the larger surface roughness. That is, as described above, if the first primary surface and the second primary surface of the porous metal sheet have different surface roughnesses, and the first primary surface has a larger surface roughness than the second primary surface, then the adhesive layer may be formed on at least the first primary surface.

[0120] As an adhesive layer, known pressure-sensitive adhesive layers or adhesive layers can be applied without any particular restrictions, and there are no particular limitations on their thickness, etc.

[0121] If necessary, the buffer film may include additional layers. For example, additional layers such as graphite sheets or graphite layers may be present to improve thermal diffusion properties in the planar direction.

[0122] However, for the preferred configuration of thin devices, the buffer film can consist only of a porous metal sheet and an adhesive layer, thereby enabling thinner devices. This is possible because the porous metal sheet included in the buffer film can individually ensure the electromagnetic shielding characteristics, heat dissipation characteristics, and shock resistance required for devices such as OLEDs.

[0123] Therefore, in this disclosure, devices such as OLEDs can be provided that ensure the required heat dissipation characteristics, electromagnetic shielding characteristics, and shock resistance (or shock mitigation characteristics) in a simple structure without problems such as increased price, process complexity, and increased thickness.

[0124] This disclosure also relates to OLEDs, specifically including OLEDs of the buffer film.

[0125] The OLED disclosed herein may include a substrate; an organic light-emitting layer formed on the upper part of the substrate; and a buffer film formed on the lower part of the substrate. Figure 2 The diagram schematically illustrates an OLED comprising an organic light-emitting layer 20, a substrate 10, and a buffer film 100 in sequence. The aforementioned buffer film can be applied as the buffer film.

[0126] As used above, the upper and lower parts of the terminology define the positional relationship between the organic light-emitting layer and the buffer film surrounding the substrate. Therefore, in actual transportation or usage conditions, the organic light-emitting layer may not necessarily be located above the buffer film.

[0127] There are no particular restrictions on the type of substrate used in OLEDs. Typically, glass or plastic substrates are used as substrates when configuring OLEDs, and in this disclosure, commonly used substrates can be used without restriction.

[0128] In one example, a plastic substrate can be used as the substrate. Using a plastic substrate is advantageous for configuring relatively thin and flexible OLEDs. However, when using a plastic substrate, the OLED becomes more susceptible to external shocks and is less able to effectively withstand electromagnetic waves or heat. However, when the buffer film of this disclosure is applied, the advantages of the plastic substrate can be utilized while addressing these disadvantages.

[0129] There are no particular restrictions on the type of organic light-emitting layer formed on the substrate. Typically, the organic light-emitting layer exists between opposing positive electrodes (anodes) and negative electrodes (cathodes) and includes an organic layer comprising at least the light-emitting layer, wherein such a general configuration may be used without particular limitation herein.

[0130] In addition to the light-emitting layer, the organic layer may also include necessary known layers, such as an electron injection layer, an electron transport layer, a hole transport layer, and / or a hole injection layer.

[0131] In an organic light-emitting layer, either the positive or negative electrode can be a transparent electrode, and the other can be a reflective electrode. In some cases, both electrodes can also be transparent electrodes.

[0132] Methods and materials for constructing organic light-emitting layers in this manner are known, and these known methods and materials can also be applied to the present disclosure.

[0133] In the above structure, the buffer film is a layer formed on the lower part of the substrate, which can effectively remove the heat generated by the organic light-emitting layer or other components of the OLED, shield electromagnetic waves generated from or propagating to the organic light-emitting layer, and reduce or mitigate external impacts.

[0134] Furthermore, as described above, if the buffer film has a porous metal sheet with different surface roughness on the first and second main surfaces and a larger surface roughness on the first surface compared to the second surface, the first main surface of the porous metal sheet in the buffer film can be set closer to the organic light-emitting layer than the second main surface.

[0135] Furthermore, by exhibiting the aforementioned reflectivity, it does not cause the problem of reduced visibility in OLEDs, and by ensuring the aforementioned specific resistance, it is possible to form potential points or insulating sites in OLEDs, if necessary.

[0136] OLEDs can also include electronic components formed on the underside of the buffer film as an additional component. Figure 3 This configuration is illustrated, showing a configuration in which an organic light-emitting layer 20, a substrate 10, a buffer film 100, and an electronic component 40 are sequentially included.

[0137] The electronic component is a configuration for applying signals to the driving circuit portion that drives the organic light-emitting layer. Therefore, in this case, the substrate or organic light-emitting layer may include the driving circuit portion for driving the organic light-emitting layer, and the driving circuit portion may be connected to the electronic component.

[0138] Even in such Figure 3 In its configuration, the buffer film 100 can also prevent the heat generated in the organic light-emitting layer 20 and / or electronic components 40 from being transferred to each other, and shield the electromagnetic waves generated in the organic light-emitting layer 20 and / or electronic components 40 from propagating to each other. In addition, even when components such as the substrate 10 are thinned, damage to the device caused by external impacts can be prevented.

[0139] There are no particular restrictions on the specific configuration of the electronic components and drive circuits, and known configurations can be used.

[0140] Furthermore, with this configuration, only a buffer film can exist between the electronic components and the substrate. Therefore, thinner devices can be configured. This is possible because the porous metal sheet included in the buffer film can individually ensure the electromagnetic shielding, heat dissipation, and shock resistance required by OLEDs.

[0141] Beneficial effects

[0142] This disclosure provides information on buffer films and their uses, particularly buffer films for organic light-emitting devices. Attached Figure Description

[0143] Figure 1 This is a schematic diagram illustrating the structure of a conventional OLED.

[0144] Figure 2 and 3 The diagram is shown schematically to illustrate the OLED of this application.

[0145] Figure 4 Photographs are shown to illustrate the process used to evaluate impact resistance.

[0146] [Figure Labels]

[0147] 10: Base

[0148] 20: Organic light-emitting layer

[0149] 30, 40: Electronic components

[0150] 100: Buffer membrane Detailed Implementation

[0151] The present disclosure will be described in detail below through embodiments, but the scope of the present disclosure is not limited to the following embodiments.

[0152] 1. Evaluation of the reflectivity of porous metal sheets

[0153] The reflectance of the porous metal sheet (metal foam) included in the buffer film to wavelengths from 400 nm to 800 nm was evaluated using a UV spectroscopy instrument (Shimadzu UV-2600, manufactured by Shimadzu). An integrating sphere (ISR-2600) was mounted on the instrument, and reflectance was measured in diffuse reflectance mode (diffuse reflectance measurement) according to the manual, using BaSO4 as the standard material. In this manner, reflectance was evaluated at 0.5 nm intervals from 400 nm to 800 nm, and the average of the evaluated reflectance values ​​was calculated to determine the reflectance.

[0154] 2. Assessment of thermal diffusivity

[0155] The thermal diffusivity of the porous metal sheet (metal foam) included in the buffer membrane was evaluated using the LFA (Laser Flash Analysis) method, where the evaluated thermal diffusivity is the thermal diffusivity in the xy plane. When measuring the thermal diffusivity, a microflash device (LFA46Hyper flash lamp, manufactured by Netzsch) was used (in-plane measurement mode). The sample (metal foam) was punched into a circle with a diameter of approximately 25.4 mm and then...

[0156] 3. Surface roughness assessment

[0157] The surface roughness of the porous metal sheet was measured using a 3D laser microscope (Keyence VK-X160 model).

[0158] 4. Evaluation of resistivity

[0159] The resistivity of a porous metal sheet (metal foam) contained in a buffer membrane was measured using the four-point probe (FPP) method. A CMT-SR2000N (manufactured by AIT) was used as the instrument in this measurement.

[0160] 5. Assessment of shock resistance (pulse attenuation)

[0161] like Figure 4 As shown, a drop ball device is used to evaluate impact resistance. Figure 4 In the diagram, reference numeral 1000 indicates the drop ball position, reference numeral 2000 indicates the sample position, and reference numeral 3000 indicates the measurement section. The porous metal sheet (metal foam) is placed... Figure 4 The sample location was determined, and balls of the same weight were dropped from the same height onto the porous metal sheet using a drop ball device. The peak impact force was measured by the measuring section. The table below describes the compression ratio obtained by comparing the results measured in the above manner with the peak impact force measured by dropping the ball without the porous metal sheet.

[0162] Example 1.

[0163] Metal foams were prepared as porous metal sheets. The metal foams were prepared using copper powder with an average particle size (median particle size, D50 particle size) of approximately 60 μm. Here, copper is characterized by a thermal conductivity of approximately 401 W / mK, a Young's modulus of approximately 110 GPa to 128 GPa, a Poisson's ratio of approximately 0.34, and a thermal conductivity of approximately 1.7 × 10⁻⁶ W / mK. -6 The resistivity is approximately Ωcm and the specific resistance is approximately 8.96 g / cm. 3 Materials with a density of approximately [density value missing]. A slurry was prepared by mixing 30g copper powder, 20g terpineol, 8g ethylhexyl decanoate, 3g polyvinyl acetate, and 1g leveling agent (BYK, BYK-358N). The slurry was coated as a film, dried in an oven at 120°C for 30 minutes, and then sintered at approximately 1000°C for about 2 hours under a hydrogen / argon atmosphere to prepare a metal foam. In the above process, the slurry was coated onto a smooth surface with a small surface roughness, and the side of the smooth surface opposite to the coated side was exposed to air for sintering.

[0164] Nickel is then plated onto the resulting copper foam. Here, nickel has a thermal conductivity of approximately 91 W / mK, a Young's modulus of approximately 200 GPa, a Poisson's ratio of approximately 0.31, and a molecular weight of approximately 6.9 × 10⁻⁶. -6 The resistivity is approximately Ωcm and the specific resistance is approximately 8.908 g / cm. 3 Materials with a density of approximately [value missing].

[0165] Electroplating was performed using a known method. A copper foam was placed in a solution containing dissolved NiSO4, NiCl2, or H2BO3, and nickel was deposited onto the surface of the copper foam using electroplating, with a platinum electrode and the copper foam serving as the positive and negative electrodes, respectively. The plating process lasted approximately one minute to obtain a nickel-plated copper foam. The nickel plating thickness in the copper foam was approximately 97 nm. The nickel plating thickness was determined by SEM (scanning electron microscopy) while the sample (metal foam) was cut with a focused ion beam (FIB) to expose the cross-section. The prepared metal foam had a thickness of approximately 150 μm and a porosity of approximately 74%. Furthermore, the surface roughness (1Sa) of one side (the first major surface) of the metal foam was approximately 8.2 μm, and the surface roughness (2Sa) of the other side (the second major surface) was approximately 5.5 μm. An acrylic pressure-sensitive adhesive layer was formed on the first major surface to prepare a buffer film.

[0166] Example 2.

[0167] A porous metal sheet was prepared in the same manner as in Example 1, except that it was prepared by nickel plating for 2 minutes. The nickel plating thickness in the copper foam was approximately 142 nm. The resulting metal foam had a thickness of approximately 151 μm and a porosity of approximately 74%. Furthermore, the surface roughness (1Sa) of one side (the first major surface) of the metal foam was approximately 8.2 μm, and the surface roughness (2Sa) of the other side (the second major surface) was approximately 5.5 μm. An acrylic pressure-sensitive adhesive layer was formed on the first major surface to prepare a buffer film.

[0168] Example 3.

[0169] A porous metal sheet was prepared in the same manner as in Example 1, except that it was prepared by nickel plating for 4 minutes. The nickel plating thickness in the copper foam was approximately 209 nm. The resulting metal foam had a thickness of approximately 153 μm and a porosity of approximately 72%. Furthermore, the surface roughness (1Sa) of one side (the first major surface) of the metal foam was approximately 8.1 μm, and the surface roughness (2Sa) of the other side (the second major surface) was approximately 5.5 μm. An acrylic pressure-sensitive adhesive layer was formed on the first major surface to prepare a buffer film.

[0170] Example 4.

[0171] A porous metal sheet was prepared in the same manner as in Example 1, except that it was prepared by nickel plating for 8 minutes. The nickel plating thickness in the copper foam was approximately 536 nm. The resulting metal foam had a thickness of approximately 155 μm and a porosity of approximately 70%. Furthermore, the surface roughness (1Sa) of one side (the first major surface) of the metal foam was approximately 8.0 μm, and the surface roughness (2Sa) of the other side (the second major surface) was approximately 5.5 μm. An acrylic pressure-sensitive adhesive layer was formed on the first major surface to prepare a buffer film.

[0172] Example 5.

[0173] An acrylic pressure-sensitive adhesive layer is formed on the second main surface of the porous metal sheet prepared in Example 1 to prepare a buffer film.

[0174] Comparative Example 1.

[0175] No additional nickel plating was performed on the same copper metal foam prepared in Example 1, and a pressure-sensitive adhesive layer was formed on the first major surface to prepare a buffer film.

[0176] The evaluation results of each embodiment and comparative example are described in Table 1.

[0177] In Table 1 below, the electromagnetic shielding capability is measured according to ASTM D4935 in the range of 30MHz to 1.5GHz.

[0178] [Table 1]

[0179]

[0180] As can be seen from Table 1 above, the buffer films according to these embodiments can individually meet the impact resistance, heat dissipation characteristics and electromagnetic wave shielding capabilities required by OLEDs and other devices.

[0181] Furthermore, it can be determined that the porous metal sheet in the buffer film of the above embodiments exhibits low reflectivity, which allows it to be included in OLEDs without causing visibility problems, and it exhibits appropriate specific resistance, which allows it to form the insulating sites or potential points required for OLEDs, etc. However, it can be determined that the buffer film of Comparative Example 1 exhibits excessively high reflectivity.

Claims

1. A buffer membrane, comprising: Porous metal sheet, The porous metal sheet has an average reflectivity of 50% or less relative to light with wavelengths ranging from 400 nm to 800 nm. The porous metal sheet has a first primary surface and a second primary surface, the first primary surface and the second primary surface having different surface roughness, and The ratio of the surface roughness 1Sa of the first primary surface to the surface roughness 2Sa of the second primary surface is greater than 1 and is 3 or less.

2. The cushioning film of claim 1, wherein the specific resistance of the porous metal sheet is 1.0 x 10 -5 Ωcm or more.

3. The buffer membrane according to claim 1, wherein the thermal diffusivity of the porous metal sheet is 25 mm. 2 / second or greater.

4. The buffer membrane according to claim 1, wherein 1Sa is 6.5 μm or larger.

5. The buffer membrane according to claim 1, wherein the thickness of the porous metal sheet is 50 μm or greater.

6. The buffer membrane according to claim 1, wherein the porous metal sheet comprises a first metal with a Young's modulus of 160 GPa or less and a second metal with a Young's modulus greater than 160 GPa.

7. The buffer membrane according to claim 1, wherein the porous metal sheet comprises a resistivity of 4.3 × 10⁻⁶. -6 The first metal has a resistance of Ωcm or less and a specific resistance greater than 4.3 × 10⁻⁶. -6 The second metal of Ωcm.

8. The buffer membrane of claim 1, wherein the porous metal sheet comprises a first metal and a second metal different from the first metal, and wherein the Poisson's ratio of each of the first metal and the second metal is in the range of 0.1 to 0.

7.

9. The buffer membrane according to claim 1, wherein the porous metal sheet is a metal foam, a sintered metal fiber sheet, or a metal mesh.

10. The buffer membrane according to claim 1, further comprising: An adhesive layer on one or both sides of the porous metal sheet.

11. The buffer membrane of claim 10, wherein the porous metal sheet has a first primary surface and a second primary surface having a surface roughness different from the first primary surface. Wherein the surface roughness of the first primary surface is greater than the surface roughness of the second primary surface, and The adhesive layer is formed on the first main surface.

12. An organic light-emitting device, comprising: Base; An organic light-emitting layer is formed on the upper part of the substrate; and A buffer membrane formed on the lower part of the substrate according to any one of claims 1 to 11.

13. The organic light-emitting device of claim 12, wherein the porous metal sheet has a first primary surface and a second primary surface having a surface roughness different from the first primary surface. Wherein the surface roughness of the first primary surface is greater than the surface roughness of the second primary surface, and The first primary surface is positioned closer to the organic light-emitting layer than the second primary surface.

14. The organic light-emitting device according to claim 12, further comprising: An electronic component is formed on the lower part of the buffer film, wherein only the buffer film exists between the electronic component and the substrate.

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