Transparent selective frequency shielding unit

Abstract

The present invention relates to a selective frequency shielding structure comprising a transparent substrate and a pattern layer including a conductive material formed on the transparent substrate, wherein the pattern layer is formed on a single surface of the transparent substrate. According to the present invention, high optical transmission characteristics in the visible light and infrared bands and selective multi-band frequency shielding performance can be simultaneously realized.

Description

Technology Field

[0001] The present invention relates to a frequency surface having broadband light transmission characteristics and selectively having frequency shielding performance. Background Technology

[0002] The present invention relates to a method for manufacturing a selective frequency shielding surface having broadband light transmission characteristics from the visible light to the infrared band, and can be used in various fields requiring broadband transparency, such as electromagnetic shielding, RFID, WLAN security, mobile communication equipment, and military applications.

[0003] Conventional technologies include selective frequency surface structure technology implemented with a multilayer structure, energy-saving window technology, and optically transparent selective frequency surface absorber technology.

[0004] Selective frequency surface structure technology implemented through a multilayer structure is generally a technology composed of multilayer structures such as dielectric spacers and back reflectors; however, the application of back reflectors makes it difficult to expect improvements in optical transmission performance.

[0005] In addition, since energy-saving window technology requires specific radio wave penetration characteristics in the frequency bands of GSM (Global System for mobile Communications), GPS (Global positioning systems), and UMTS (Universal Mobile Telecommunication System), it is a technology that requires the implementation of a selective frequency surface with a bandwidth of typically 800 MHz to 2 GHz.

[0006] In addition, the technology requiring transmission performance in the visible light band is an optically transparent selective frequency surface absorber technology. The conductive oxide-based selective frequency surface absorber is a technology that has low electromagnetic wave absorption characteristics due to its lower conductivity compared to metals, and is a technology in which optical transmission characteristics deteriorate in the mid-infrared band and above (~2.5㎛), and is a technology in which it is difficult to secure conductivity loss and heat resistance characteristics at temperatures above 300℃ during high-temperature heat treatment in the atmosphere.

[0007] Infrared and radio wave detection technologies require broadband transparent selective frequency surface fabrication technology as a common monitoring technology applicable to military and civilian fields.

[0008] The matters described in the background technology above are intended to aid in understanding the background of the invention and may include matters that are not prior art already known to those skilled in the art to which this technology belongs. Prior art literature

[0009] Korean Registered Patent Publication No. 10-1014972 The problem to be solved

[0010] The present invention has been devised to solve the aforementioned problems, and the purpose of the present invention is to provide a selective frequency shielding structure capable of simultaneously realizing high optical transmission characteristics in the visible light and infrared bands and selective frequency shielding performance. means of solving the problem

[0011] A selective frequency shielding structure according to one aspect of the present invention comprises a transparent substrate and a pattern layer including a conductive material formed on the transparent substrate, wherein the pattern layer is formed on a single surface.

[0012] In addition, the pattern layer is characterized by having unit cells arranged on the transparent substrate.

[0013] In particular, the unit cell is characterized by having a planar regular polygonal shape of an isotropic resonance structure.

[0014] Furthermore, when shielding characteristics are required for multiple (n) frequency bands, the pattern of the isotropic resonant structure includes multiple (n) planar regular polygonal unit patterns.

[0015] Furthermore, the planar shape of the unit cell is characterized by being identical to the planar shape of the unit pattern.

[0016] In particular, the plurality of the above unit patterns are characterized by being formed as unit patterns with different lengths from the outermost unit pattern to the innermost unit pattern.

[0017] Meanwhile, the multiple unit pattern sizes are characterized by being less than or equal to λ / 2 of the specific shielding required frequency wavelength (λ).

[0018] In addition, the line width of the unit pattern is characterized as being 50 to 250 μm.

[0019] In addition, the material of the transparent substrate is characterized as being one of Ge, Si, GaAs, GaP, ZnS, ZrO2, Y2O3, Al2O3, ALON (Aluminum oxynitride), Spinel, MgO, SiO2, BaF2, LiF, CaF2, sulfide-based, selenide-based, telluride-based optical materials, and chalcogenide glass.

[0020] In addition, the pattern layer is characterized by being a monocrystalline, binary, or ternary metal conductor selected from the group consisting of Au, Ag, Cu, Ti, Co, Fe, and Ni, or a conductive material with a sheet resistance of 22.5 ohm / sq. or less. Effects of the invention

[0021] The present invention is a transparent selective frequency surface structure using an isotropic resonant structure single pattern layer, and the structure implemented through the present invention has the following features.

[0022] 1. It is possible to implement multi-band frequency shielding characteristics with multiple bands of frequency shielding characteristics using multiple unit patterns within a unit cell.

[0023] 2. It has broadband transmission characteristics with an optical transmittance of 70% or more in the visible light and infrared bands, formed as an isotropic resonant structure on a single surface of a transparent substrate.

[0024] 3. It has heat resistance properties with no conductivity loss up to 500℃. Brief explanation of the drawing

[0025] FIG. 1 is a side view of the selective frequency shielding structure of the present invention. Figures 2 and 3 illustrate examples of the unit cell of Figure 1. Figure 4 shows the selective radio wave shielding characteristics of the first embodiment of the present invention. Figure 5 shows the selective radio wave shielding characteristics of the second embodiment of the present invention. Figure 6 shows the heat resistance characteristics of the second embodiment of the present invention. Figure 7 shows the optical transmission characteristics by wavelength according to one embodiment of the present invention. Specific details for implementing the invention

[0026] In order to fully understand the present invention, the operational advantages of the present invention, and the objectives achieved by the implementation of the present invention, reference must be made to the accompanying drawings illustrating preferred embodiments of the present invention and the contents described therein.

[0027] In describing preferred embodiments of the present invention, known technologies or repetitive descriptions that may unnecessarily obscure the essence of the invention will be shortened or omitted.

[0028] FIG. 1 is a side view of the selective frequency shielding structure of the present invention, and FIG. 2 and FIG. 3 illustrate examples of the unit cell of FIG. 1.

[0029] Hereinafter, a selective frequency shielding structure according to an embodiment of the present invention will be described with reference to FIGS. 1 and FIGS. 2.

[0030] Infrared and radio wave detection technologies require broadband transmission and selective shielding performance as common monitoring technologies applicable to military and civilian sectors.

[0031] The present invention is a structure capable of simultaneously implementing broadband optical characteristics and selective frequency shielding characteristics so that it can be used in various fields requiring broadband transparency, such as electromagnetic shielding, RFID, WLAN security, mobile communication equipment, and military applications.

[0032] To this end, the present invention aims to achieve this objective by utilizing an isotropic resonant structure and a single-plane pattern layer.

[0033] Specifically, the selective shielding structure of the present invention is a structure in which a pattern layer (10) is formed on a transparent substrate (20) by a patterning process.

[0034] Light transmission performance is achieved through a transparent substrate, and unlike conventional multilayer structures, the pattern layer consists of a pattern layer implemented on a single surface.

[0035] In other words, since conventional spacers and rear reflectors are not applied, high transmittance can be achieved in the visible and infrared bands.

[0036] The pattern layer (10) is formed such that a plurality of identical unit cells (1) are arranged face-to-face on the plane of the substrate (20).

[0037] In order to achieve a constant shielding characteristic regardless of the angle of incidence and polarization characteristics of the radio waves, the unit cell (1) is preferably configured in a planar regular polygonal shape as shown in the illustration, and a square shape is illustrated in FIG. 2 and a regular hexagonal shape is illustrated in FIG. 3.

[0038] In the present invention, a plurality of unit patterns of isotropic resonant structures are formed in each unit cell (1) so that shielding characteristics can be simultaneously implemented in a plurality (n) multiple radio frequency bands.

[0039] It is preferable that such a pattern be composed of unit patterns of regular polygonal shapes on a planar surface, such as a city, or more strictly, of the shape of its borders. FIG. 2 illustrates a square-shaped unit pattern (11-1, 11-2, 11-3,...,11-n), and FIG. 3 illustrates a regular hexagonal-shaped unit pattern (12-1, 12-2, 12-3,...,12-n). It is more preferable that the shape be identical to the shape of the unit cell.

[0040] Furthermore, the pattern formed in the unit cell (1) may have multiple unit patterns of different lengths arranged in a plurality, and as shown in the illustration, the pattern of an isotropic resonance structure is formed by sequentially arranging from the outermost first unit pattern (11-1, 12-1) with the longest length to the inner second unit pattern (11-2, 12-2), and the third unit pattern (11-3, 12-3) inside the second unit pattern (11-2, 12-2) to the innermost n-th unit pattern (11-n, 12-n).

[0041] More specifically, the substrate (20) is preferably determined according to the required optical transmission characteristics. If mid-infrared band transmission characteristics are required, Ge, Si, GaAs, GaP, ZnS, ZrO2, Y2O3, Al2O3, ALON (Aluminum oxynitride), Spinel, MgO, SiO2, BaF2, LiF, and CaF2 may be selected, and if far-infrared band transmission characteristics are required, sulfide-based, selenide-based, telluride-based optical materials and chalcogenide glass may be selected. If multi-band transmission characteristics are required, it is preferable to select a material that has transmission characteristics in the required wavelength band.

[0042] Also, it is preferable that the unit pattern size within the unit cell (1) be less than or equal to λ / 2 of the specific shielding required frequency wavelength (λ).

[0043] Furthermore, it is desirable that the line width of the unit pattern be determined in the range of 50 to 250 μm and designed according to the dielectric constant and thickness of the substrate.

[0044] The material forming the pattern layer (10) is preferably selected from one or more metal conductors selected from the group consisting of Au, Ag, Cu, Ti, Co, Fe, Ni, etc., or from a binary or ternary alloy group, and is preferably a conductive material having a sheet resistance of 22.5 ohm / sq. or less, and a multilayer thin film structure of heterogeneous materials may be applied.

[0045] FIG. 4 shows the selective radio wave shielding characteristics of the first embodiment of the present invention, and FIG. 5 shows the selective radio wave shielding characteristics of the second embodiment of the present invention. Specific embodiments and test results will be explained below.

[0046] According to an embodiment of the present invention, a pattern layer (10a, 10b) is designed on a sapphire substrate having mid-infrared transmission characteristics as an isotropic resonant structure (square) according to the frequency at which shielding characteristics are required, and a transparent selective frequency surface is fabricated using an Ag conductive material through a gravure offset process.

[0047] The first embodiment is an optional frequency surface requiring single (when n=1 in FIG. 2) frequency band shielding, wherein the frequency requiring shielding is 10 GHz and the optional frequency surface is implemented on a single surface of a sapphire substrate (5T); the second embodiment is an optional frequency surface requiring dual (when n=2 in FIG. 2) frequency band shielding, wherein the frequencies requiring shielding are 6 GHz and 10 GHz and the optional frequency surface is implemented on a single surface of a sapphire substrate (2T and 5T).

[0048] Referring to FIG. 4, it can be seen that although the change in resonance frequency occurs due to the difference in line width between the design value and the implemented value, the predicted value (210) and the measured value (220) of the radio wave shielding characteristics match well for a frequency of 10 GHz.

[0049] Also, referring to FIG. 5, it can be seen that although there are differences in shielding effect and resonant frequency depending on the substrate thickness, shielding characteristics are exhibited in the required selective frequency band. 310 is a selective frequency shielding surface characteristic of 6 GHz and 10 GHz implemented on sapphire (2T), and 320 is a selective frequency shielding surface characteristic of 6 GHz and 10 GHz implemented on sapphire (5T).

[0050] Next, FIG. 6 shows the heat resistance characteristics of the second embodiment (320 in FIG. 6). Although there is a slight difference in the resonance frequency due to the change in electrical conductivity after heat treatment in an atmospheric atmosphere at 500°C, when comparing the electromagnetic shielding characteristics (410) before heat treatment at 500°C and the electromagnetic shielding characteristics (420) after heat treatment, it can be seen that it has heat resistance characteristics at 500°C.

[0051] The following table summarizes the characteristics of the first embodiment and the second embodiment implemented in sapphire (5T).

[0052] division Selective frequency (design criteria) Implementation resonant frequency Shielding bandwidth (S21=-10dB standard) Optical transmittance (@4㎛) First embodiment 10 GHz 9.8 GHz 2.34 GHz 83.4% 2nd embodiment 6 & 8 GHz 5.9 & 9.8 GHz 2.46 GHz 80.3%

[0053] The optical transmittance of a multi-band selective frequency surface can be predicted using a value estimated by the Area Ratio (AR), which is defined as the area fraction of the conductive material per unit cell area.

[0054]

[0055] For a substrate having an optical transmittance of 85% (@1.55 & 4㎛), the change in transmittance according to AR is as shown in Fig. 7. Here, the change in transmittance according to the change in AR has the same change in transmittance for the same linewidth regardless of the isotropic resonant structure shape.

[0056] As shown in FIG. 7, the optical transmittance prediction result according to AR indicates that even if a surface with five selective frequency shielding characteristics is implemented, a transmittance of 70% or more based on a 4㎛ wavelength (520) can be achieved. With the range of AR being 0.03 to 0.15%, 510 represents the change in optical transmittance based on a 1.55㎛ wavelength, indicating that a structure capable of achieving a transmittance of 70% or more based on a 4㎛ wavelength can achieve a transmittance of 70% or more in the visible light band as well.

[0057] Although the present invention has been described above with reference to the illustrated drawings, it is obvious to those skilled in the art that it is not limited to the described embodiments and can be modified and varied in various ways without departing from the spirit and scope of the invention. Accordingly, such modifications or variations should be deemed to fall within the scope of the claims of the present invention, and the scope of rights of the present invention should be interpreted based on the appended claims. Explanation of the symbols

[0058] 10, 10a, 10b: Pattern layer 20 : Substrate 12: Unit cell 11-1, 11-2, 11-3, 11-n: Unit patterns of the first embodiment 12-1, 12-2, 12-3, 12-n: Unit patterns of the first embodiment

Claims

Claim 1 Transparent substrate; The invention comprises a pattern layer including a conductive material formed on the transparent substrate, wherein the pattern layer is formed on a single surface of the transparent substrate, wherein the pattern layer is characterized by having a plurality of unit cells repeatedly arranged on the transparent substrate, wherein the unit cells are characterized by having a planar regular hexagonal shape as a pattern structure of an isotropic resonance structure, wherein the pattern of the isotropic resonance structure includes a plurality of planar regular hexagonal unit patterns, wherein the first unit pattern having the longest length and being the outermost, the second unit pattern inside the first unit pattern, and the third unit pattern inside the second unit pattern are arranged sequentially, wherein the width of each of the first unit pattern, the second unit pattern, and the third unit pattern is λ / 2 or less of the wavelength (λ) of a specific shielding required frequency, wherein the line width of the first unit pattern, the second unit pattern, and the third unit pattern is 50 to 250 μm, wherein the material of the transparent substrate is Al2O3, and wherein the pattern layer has a sheet resistance of 22.5 ohm / sq. A transparent selective frequency surface is manufactured using an Ag material as the conductive material through a gravure offset process, and the Area Ratio (AR), defined as the area fraction of the conductive material per unit cell area, A selective frequency shielding structure characterized by having an optical transmittance of 70% or more on a transparent substrate having an optical transmittance of 85% at a wavelength of 1.55㎛ and 4㎛ for 0.03 to 0.15%. Claim 2 delete Claim 3 delete Claim 4 delete Claim 5 A selective frequency shielding structure according to claim 1, characterized in that the planar shape of the unit cell is identical to the planar shape of the unit pattern. Claim 6 delete Claim 7 delete Claim 8 delete Claim 9 delete Claim 10 delete

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