A light-transmissive ultra-wideband electromagnetic shield based on an indium tin oxide film

Abstract

The application discloses a light-transmitting ultra-wideband electromagnetic shielding device based on an indium tin oxide film, which is a hollow rectangular shell, and the six side walls have the same structure; borosilicate glass is used as a substrate for the side walls; when the electromagnetic attenuation scene is applied, ITO films are arranged on the outer surfaces of the borosilicate glass, and patterns are etched on the ITO films; when the electromagnetic shielding scene is applied, ITO films are arranged on the inner and outer surfaces of the borosilicate glass respectively, and patterns are etched on the ITO films respectively.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of metamaterials, and discloses a light-transmissive ultra-wideband electromagnetic shielding device based on an indium tin oxide (ITO) film. BACKGROUND

[0002] With the rapid development of science and technology, electronic devices are widely used in daily life, and a large number of electromagnetic waves of different frequencies are radiated from various electronic components. In some areas where electronic devices are densely used, the ubiquitous electromagnetic waves in space can interfere with some precision electronic devices, seriously affecting the working stability of the devices, and therefore electromagnetic shielding metamaterials emerge as the times require. The electromagnetic shielding metamaterial is a new type of wave absorber, which changes people's understanding of electromagnetic absorbing materials and makes it possible to artificially manipulate electromagnetic waves. However, most of the existing electromagnetic shielding metamaterials use metal as the resonant structure and printed boards as the intermediate dielectric layer, which are difficult to be applied to liquid crystal screens, visual windows, displays and other electromagnetic shielding objects that need to be observed in the visible light wave band. SUMMARY

[0003] The application aims to provide a light-transmissive ultra-wideband electromagnetic shielding device based on an indium tin oxide film. The ITO film is etched on borosilicate glass in a pattern, and the ITO film with adjustable sheet resistance and the borosilicate glass together constitute electromagnetic resonance, which has a certain shielding effect on electromagnetic waves.

[0004] The technical solution of the application is as follows: a light-transmissive ultra-wideband electromagnetic shielding device based on an indium tin oxide film is a hollow rectangular shell, and the six side walls have the same structure. Borosilicate glass is used as the substrate of the side wall. When acting in an electromagnetic attenuation scene, an ITO film is arranged on the outer surface of the borosilicate glass, and a pattern is etched on the ITO film. When acting in an electromagnetic shielding scene, ITO films are arranged on the inner and outer surfaces of the borosilicate glass, respectively, and patterns are etched on the ITO films.

[0005] Compared with the prior art, the application has the following advantages:

[0006] (1) The resonant characteristics and light-transmissive property of the ITO film are ingeniously utilized to construct a light-transmissive ultra-wideband electromagnetic shielding device.

[0007] (2) According to different application scenes, double-sided etching or single-sided etching can be selected, which can be used for electromagnetic shielding or attenuation, respectively.

[0008] (3) The structure is simple, the manufacturing is convenient, and the cost is low. BRIEF DESCRIPTION OF DRAWINGS

[0009] Figure 1 It is an external view of the electromagnetic shielding device of the application.

[0010] Figure 2 The figure is a schematic diagram of ITO film of the present application, wherein figure (a) is a schematic diagram of single-sided ITO film, and figure (b) is a schematic diagram of double-sided ITO film.

[0011] Figure 3 The figure is a schematic diagram of ITO unit pattern.

[0012] Figure 4 The figure is a curve diagram of electric field intensity value at the center of electromagnetic shield of double-sided ITO film.

[0013] Figure 5 The figure is a curve diagram of shielding effectiveness of electromagnetic shield of double-sided ITO film.

[0014] Figure 6 The figure is a curve diagram of electric field intensity value at the center of electromagnetic shield of single-sided ITO film.

[0015] Figure 7 The figure is a curve diagram of shielding effectiveness of electromagnetic shield of single-sided ITO film. DETAILED DESCRIPTION

[0016] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative effort fall within the scope of the present application.

[0017] It should be noted that all directional indications, such as upper, lower, left, right, front, back, etc., in the embodiments of the present application are only used to explain the relative position relationship, movement condition, etc. between components in a certain posture (as shown in the drawings), and if the certain posture changes, the directional indications also change accordingly.

[0018] In addition, the description such as "first", "second" and the like in the present application is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, for example, two, three, etc., unless otherwise specifically limited.

[0019] In the present application, unless otherwise specifically defined and limited, the terms "connection", "fixing" and the like should be understood in a broad sense, for example, "fixing" can be fixed connection, or detachable connection, or integral; "connection" can be mechanical connection, or electrical connection. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0020] Furthermore, the technical solutions of the various embodiments of the present invention can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by the present invention.

[0021] The following section will further introduce the specific implementation method, as well as the technical difficulties and inventive points of this invention, using examples from this design.

[0022] This invention utilizes ITO thin films and borosilicate glass to fabricate a light-transmitting ultra-wideband electromagnetic shield based on indium tin oxide (ITO) thin films. It features ultra-wideband coverage, light transmittance, simple structural design, low cost, and ease of electromagnetic shielding implementation. Furthermore, this invention provides two electromagnetic shielding effects: electromagnetic attenuation and electromagnetic shielding, corresponding to single-sided and double-sided etching of the ITO thin films, respectively. This light-transmitting ultra-wideband electromagnetic shield based on ITO thin films is a hollow rectangular shell with identical compositions on its six sidewalls. The sidewalls use borosilicate glass as a substrate. In electromagnetic attenuation scenarios, an ITO thin film is deposited on the outer surface of the borosilicate glass, and a pattern is etched onto the ITO film. In electromagnetic shielding scenarios, ITO thin films are deposited on both the inner and outer surfaces of the borosilicate glass, and patterns are etched on each surface. All patterns are identical.

[0023] Considering that ITO is a surface resistive material, in addition to the resonant loss of the surface resonant structure, ohmic loss also accounts for a large part. Furthermore, to ensure angular stability, [the following was chosen]. Figure 3 The unit pattern shown achieves wide-bandwidth and high-intensity electromagnetic wave absorption.

[0024] The borosilicate glass has a dielectric constant ε = 4, a magnetic permeability μ = 1, and an electrical conductivity σ = 0 S / m. Considering the fabrication process, the sheet resistance of the ITO thin film is set to 5 Ω / m. 2 Electromagnetic numerical analysis was performed using the full-wave finite integration method in the frequency domain solver of CST software. The optimized structural dimensions are as follows: Figure 1 , Figure 2 and Figure 3 As shown: the ITO film thickness is 18.5 μm, and the borosilicate glass thickness is 1400 μm. The absorber is 200 mm long, 150 mm wide, and 60 mm high. Each sidewall is divided into several 600 μm x 600 μm units, and etching is performed on the ITO film. A 400 μm x 100 μm rectangle is symmetrically etched away from each of the four sides of the unit to obtain the etched pattern unit. The etched rectangles are symmetrical about the central axis of the pattern unit. All the etched pattern units together form the etched pattern.

[0025] The electromagnetic absorber will be further explained below with reference to the accompanying drawings and specific examples.

[0026] Example 1:

[0027] like Figure 4 The figure shows the electric field strength at the center of the electromagnetic shielding device with double-sided ITO film, which is between 0.005 and 0.06 V / m.

[0028] According to the definition of shielding effectiveness:

[0029]

[0030] Where E0 is the electric field value at a point in space without the electromagnetic absorber, and E1 is the electric field value at that point in space with the electromagnetic absorber. The electric field strength in free space is 1, i.e., E0 = 1.

[0031] Based on the above formula and Figure 4 The data calculated the shielding effectiveness of the double-sided ITO film electromagnetic shield as follows: Figure 5 As shown, the shielding effectiveness is better than 28dB in the 0.5-6GHz range, reaching a maximum of 62dB, with an average shielding effectiveness of 38.5dB, making it suitable for applications requiring electromagnetic wave shielding.

[0032] Example 2:

[0033] like Figure 6 The figure shows the electric field strength at the center of a single-sided ITO thin film electromagnetic shield, with most values ​​ranging from 0.002 to 0.02 V / m. Based on the above formula and... Figure 6 The data calculated the shielding effectiveness of a single-sided ITO film electromagnetic shield as follows: Figure 7 As shown, the shielding effectiveness is better than 5dB within the 0.2-6GHz range, reaching a maximum of 58dB, with an average shielding effectiveness of 28dB, making it suitable for applications requiring a certain level of electromagnetic wave attenuation.

[0034] In summary, the ultra-wideband transparent electromagnetic shielding device based on indium tin oxide (ITO) thin film of this invention uses ITO thin film and glass to replace the traditional copper and dielectric substrate in constructing a metamaterial unit structure, thereby achieving visible light transparency of the overall structure. Simulation and test results show that this ultra-wideband transparent electromagnetic shielding device based on ITO thin film has an ultra-wideband absorption bandwidth, while also possessing advantages such as simple structure and low cost. It can simultaneously achieve both visibility and electromagnetic protection characteristics, and has certain practical value.

Claims

1. A light-transmissive ultra-wideband electromagnetic shield based on an indium tin oxide thin film, characterized by: The hollow rectangular shell has six side walls with the same structure, and borosilicate glass is used as the substrate of the side walls; when used in an electromagnetic attenuation scene, ITO film is arranged on the outer surface of the borosilicate glass, and a pattern is etched on the ITO film; when used in an electromagnetic shielding scene, ITO films are arranged on the inner and outer surfaces of the borosilicate glass respectively, and patterns are etched on the ITO films respectively; The etched patterns on the ITO films are the same in the two different scenes; Each side wall is divided into a plurality of units of 600 μm x 600 μm, and the ITO film is etched to obtain etched pattern units by etching away 400 μm x 100 μm rectangles on the four sides of the units symmetrically; the etched rectangles are symmetric about the central axis of the pattern units respectively, and the etched pattern units jointly form the etched pattern. The ITO film thickness is 18.5 μm, the borosilicate glass thickness is 1400 μm, and the square resistance of the ITO film is set to 5 Ω / m 2 .

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