WO2025079901A1 - Coating structure and method for manufacturing same - Google Patents

Abstract

According to an embodiment, disclosed is a coating structure comprising: a substrate; a first thin film disposed on the substrate; a second thin film disposed on the first thin film; and a metal pattern protruding from the substrate. The metal pattern penetrates the first thin film and penetrates a portion of the second thin film.

Description

Coating structure and its manufacturing method

The present invention relates to a coating structure. Specifically, the present invention relates to a low-reflection coating structure having high transmittance and low reflectance in a wide-angle visible light band.

When external image information is transmitted to the sensor through the lens in the image sensor, reflections may occur due to differences in the refractive index of the external environment and the lens. In the case of light entering the lens at a high angle, multiple reflections may occur within the lens, resulting in ghost images. The occurrence of such ghost images may cause a decrease in the performance of the image sensor.

Between two materials with different refractive indices, light is lost due to Fresnel reflection. This loss weakens the intensity of light reaching the sensor, which can affect the quality of the image. If the reflectivity between the lens and the external environment (air) is high, the light reaching the sensor after reflection within the lens can generate a ghost image, and in particular, since light incident at a wide angle generally has a higher reflectivity between the two materials, it is necessary to prevent the generation of ghost images due to a wide angle.

The present invention provides a coating structure having high transmittance and low reflectance in a wide-angle visible light band and a method for manufacturing the same.

In addition, a coating structure capable of preventing the generation of ghost images and a method for manufacturing the same are provided.

The problem to be solved in the embodiment is not limited to this, and it can be said that the purpose or effect that can be understood from the solution or embodiment of the problem described below is also included.

A coating structure according to an embodiment includes a substrate; a first thin film disposed on the substrate; a second thin film disposed on the first thin film; and a metal pattern protruding on the substrate, wherein the metal pattern penetrates the first thin film and can penetrate a portion of the second thin film.

The first thin film and the second thin film overlap in a first direction, and the first direction is an incident direction of light and may be a direction perpendicular to the first thin film and the second thin film.

The first thin film may have a refractive index of 1.3 to 3.0.

The above first thin film may include a metal oxide.

The first thin film may include TiO2, ZnO or Al2O3.

The thickness of the first thin film in the first direction may be 0.1 to 0.7 times the height of the metal pattern in the first direction.

The second thin film may have a refractive index of 1.2 to 1.4.

The second thin film may include a hydrophobic material.

The second thin film may include PTFE (Polytetrafluoroethylene) or FEP (Fluorinated ethylene propylene).

The thickness of the second thin film in the first direction may be 50 nm to 200 nm.

The above metal pattern can have a refractive index of 1.3 to 3.0.

The above metal pattern may include a metal oxide.

The above metal pattern may include TiO2, ZnO or Al2O3.

The height of the above metal pattern in the second direction may be 50 nm to 300 nm.

The refractive index of the first thin film and the metal pattern may be greater than the refractive index of the second thin film.

A method for manufacturing a coating structure according to an embodiment may include a step of dispersing PS beads on a substrate; a step of depositing a metal thin film on the substrate; a step of removing the PS beads; a step of forming a random pattern with the metal thin film; a step of forming an oxide thin film on the substrate; and a step of forming a hydrophobic thin film on the oxide thin film.

According to an embodiment, a coating structure having high transmittance and low reflectance in a wide-angle visible light band can be implemented.

Additionally, a coating structure capable of preventing the generation of ghost images can be implemented.

The various advantageous and beneficial advantages and effects of the present invention are not limited to the above-described contents, and will be more easily understood in the course of explaining specific embodiments of the present invention.

Figures 1 and 2 are conceptual diagrams of a coating structure according to an embodiment.

Figure 3 is a flow chart of a method for manufacturing a coating structure according to an embodiment.

Figures 4 to 9 are drawings showing a method for manufacturing a coating structure according to an embodiment.

Figure 10 is a graph showing the transmittance according to the wavelength of incident light of a coating structure according to an embodiment.

Figures 11 to 13 are graphs showing the transmittance of incident light according to the incident angle of the coating structure according to the embodiment.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings.

However, the technical idea of the present invention is not limited to some of the embodiments described, but can be implemented in various different forms, and within the scope of the technical idea of the present invention, one or more of the components among the embodiments can be selectively combined or substituted for use.

In addition, terms (including technical and scientific terms) used in the embodiments of the present invention can be interpreted as having a meaning that can be generally understood by a person of ordinary skill in the technical field to which the present invention belongs, unless explicitly and specifically defined and described, and terms that are commonly used, such as terms defined in a dictionary, can be interpreted in consideration of the contextual meaning of the relevant technology.

Additionally, the terms used in the embodiments of the present invention are for the purpose of describing the embodiments and are not intended to limit the present invention.

In this specification, the singular may also include the plural unless specifically stated otherwise in the phrase, and when it is described as "A and (or at least one) of B, C", it may include one or more of all combinations that can be combined with A, B, C.

Additionally, in describing components of embodiments of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used.

These terms are only intended to distinguish one component from another, and are not intended to limit the nature, order, or sequence of the component.

And, when a component is described as being 'connected', 'coupled' or 'connected' to another component, it may include not only cases where the component is directly connected, coupled or connected to the other component, but also cases where the component is 'connected', 'coupled' or 'connected' by another component between the component and the other component.

In addition, when described as being formed or arranged "above or below" each component, above or below includes not only the case where the two components are in direct contact with each other, but also the case where one or more other components are formed or arranged between the two components. In addition, when expressed as "above or below", it can include the meaning of the downward direction as well as the upward direction based on one component.

Figures 1 and 2 are conceptual diagrams of a coating structure according to an embodiment.

Referring to FIGS. 1 and 2, a coating structure (1000) according to an embodiment includes a substrate (1100), a first thin film (1200) disposed on the substrate (1100), a second thin film (1300) disposed on the first thin film (1200), and a metal pattern (1400) protruding on the substrate (1100), and the metal pattern (1400) may penetrate the first thin film (1200) and a portion of the second thin film (1300).

The coating structure (1000) may mean a structure in which a plurality of thin films are coated on the surface of an optical element such as a lens. The coating structure (1000) may be arranged on an incident surface where an optical signal is incident on the optical element when the optical signal passes through the optical element.

The coating structure (1000) may include a substrate (1100). The substrate (1100) may be a surface of an optical element on which a plurality of thin films are arranged. The substrate (1100) may mean a surface of a lens. The substrate (1100) may include a glass or plastic material. The substrate (1100) may have a refractive index of 1.3 to 2.0. An optical signal may be incident on the optical element through the substrate (1100). A first thin film (1200) may be arranged on the substrate (1100). In addition, a metal pattern (1400) may be formed on the substrate (1100). The substrate (1100) may include an incident surface (P) on which the optical signal is incident. The incident surface (P) of the substrate (1100) may be in contact with a first surface (P1) of the first thin film (1200).

The coating structure (1000) may include a first thin film (1200). The first thin film (1200) may be disposed on a substrate (1100). The first thin film (1200) may include a metal oxide. The first thin film (1200) may include TiO2, ZnO, or Al2O3. The first thin film (1200) may include an oxide. For example, the first thin film (1200) may include SiO2 or HfO2. The first thin film (1200) may include an oxide thin film. The first thin film (1200) may have a refractive index of 1.3 to 3.0. The first thin film (1200) may be disposed between the second thin film (1300) and the substrate (1100). The first thin film (1200) may overlap the second thin film (1300) in a first direction in which an optical signal is incident. The first thin film (1200) may partially overlap with the metal pattern (1400). The first thin film (1200) may overlap with the metal pattern (1400) in a second direction perpendicular to the first direction. The thickness (a) of the first thin film (1200) in the first direction may be 0.1 to 0.7 times the height (c) of the metal pattern (1400). The metal pattern (1400) may be arranged inside the first thin film (1200). The first thin film (1200) may include a first surface (P1) and a second surface (P2) arranged with the first surface (P1). The first surface (P1) of the first thin film (1200) may be in contact with the incident surface (P) of the substrate (1100). The second surface (P2) may be in contact with the second thin film (1300). The coating structure (1000) may have the effect of improving the adhesion of the metal pattern (1400) to the substrate (1100) including the first thin film (1200).

The coating structure (1000) may include a second thin film (1300). The second thin film (1300) may be disposed on the first thin film (1200). The second thin film (1300) may be disposed on the second surface (P2) of the first thin film (1200). The second thin film (1300) may have a refractive index of 1.2 to 1.4. The second thin film (1300) may include a hydrophobic material. The second thin film (1300) may include PTFE (Polytetrafluoroethylene) or FEP (Fluorinated ethylene propylene). The thickness (b) of the second thin film (1300) in the first direction may be 50 nm to 200 nm. The second thin film (1300) may overlap the first thin film (1200) in the first direction. The second thin film (1300) may partially overlap with the metal pattern (1400). The second thin film (1300) may partially overlap with the metal pattern (1400) in the second direction. The coating structure (1000) may enable easy removal of foreign substances from the coating structure (1000) by including the second thin film (1300). In addition, the coating structure (1000) may have the effect of protecting the metal pattern (1400) by including the second thin film (1300).

The coating structure (1000) may include a metal pattern (1400). The metal pattern (1400) may be protruded on the substrate (1100). The metal pattern (1400) may be disposed on an incident surface (P) of the metal pattern (1400). The metal pattern (1400) may penetrate the first thin film (1200) and a portion of the second thin film (1300). The metal pattern (1400) may penetrate the second surface (P2) of the first thin film (1200) and protrude in a first direction. The metal pattern (1400) may be disposed to penetrate the entire thickness (a) of the first thin film (1200) in the first direction. The metal pattern (1400) may be disposed to penetrate a portion of the thickness (b) of the second thin film (1300) in the first direction. The height (c) of the metal pattern (1400) may be greater than the thickness (a) of the first thin film (1200) in the first direction. The height (c) of the metal pattern (1400) may be less than the sum of the thickness (a) of the first thin film (1200) in the first direction and the thickness (b) of the second thin film (1300) in the first direction. The metal pattern (1400) may have a refractive index of 1.3 to 3.0. The metal pattern (1400) may include a metal oxide. The metal pattern (1400) may include TiO2, ZnO, or Al2O3. The height (c) of the metal pattern (1400) in the first direction may be 50 nm to 300 nm. The refractive indices of the first thin film (1200) and the metal pattern (1400) may be greater than the refractive index of the second thin film (1300). The coating structure (1000) can have a gradual change in refractive index by including a second thin film (1300) and a metal pattern (1400) having a refractive index of between 1.2 and 1.4, thereby improving the low-reflectivity of the optical element.

FIG. 3 is a flow chart of a method for manufacturing a coating structure according to an embodiment, and FIGS. 4 to 9 are drawings showing a method for manufacturing a coating structure according to an embodiment.

Referring to FIG. 4, a method for manufacturing a coating structure according to an embodiment may include a step of washing a substrate (1100).

Referring to FIG. 5, a method for manufacturing a coating structure according to an embodiment may include a step of dispersing PS beads (polystyrene beads) (10). PS beads (10) may be placed on a substrate (1100) and dispersed on the substrate (1100) through spin coating. In this case, the diameter of the PS beads (10) may be formed to be 50 nm to 1000 nm. Specifically, the PS beads (10) may be dispersed at 0 to 20 wt% in a mixed solution of an organic solvent such as divinylbenzene and DI water (deionization water). Here, the organic solvent and DI water may have a ratio of 1:1. The mixed solution is coated on the substrate, and as a coating method, spin coating may be used to coat at a speed of 1000 to 3000 RPM, or a method such as blade coating may be used. The density of the metal pattern using PS beads can be adjusted to reduce the difference in refractive index of the thin film that is different from that of the lens or substrate.

Referring to FIG. 6, a method for manufacturing a coating structure according to an embodiment may include a step of depositing a metal. A metal (titanium, zinc, aluminum, etc.) may be deposited on a substrate (1100) by a PVD (Physical Vapor Deposition) method. The metal may be deposited in the form of a metal thin film (20), and the deposition thickness of the metal thin film (20) may be 10 nm to 500 nm. Two or more types of metal may be deposited. The metal thin film (20) may be deposited on a portion excluding the PS beads (10).

Referring to FIG. 7, a method for manufacturing a coating structure according to an embodiment may include a step of removing PS beads. The PS beads may be removed by dipping into an organic solvent (such as chloroform).

Referring to FIG. 8, a method for manufacturing a coating structure according to an embodiment may include a step of forming a random pattern (30). The random pattern (30) may be formed by boiling in DI water. By boiling, oxygen in the water and a metal oxide may react to form an oxidized metal. The oxidized metal may go through processes such as Release/Migration/Re-deposition in DI water to form a random pattern (30). The water temperature may be 50°C to 95°C for 0 to 15 hours to form the pattern. When the boiling method is used, productivity may be increased.

Referring to FIG. 9, a method for manufacturing a coating structure according to an embodiment may include a nano-thin film deposition and a hydrophobicization step. An oxide film (40) (SiO2, HfO, TiO2, etc.) may be deposited by a PVD method. After the oxide film is formed, a fluorine-based material may be coated to form a hydrophobic film (50). A spin coating or blade coating method may be used as the coating method. The oxide film (40) may be deposited to increase the adhesion of the random pattern (30) to the substrate (1100). The hydrophobic film (50) may be deposited to enable easy removal of foreign substances from the coating structure. In addition, the hydrophobic film (50) may be deposited to protect the random pattern (30). In addition, since the oxide film (40) and the hydrophobic film (50) are deposited together to bring about a gradual refractive index change of the hydrophobic film (50) and the random pattern (30) between 1.2 and 1.4, the low reflectivity may be improved.

Figure 10 is a graph showing the transmittance according to the wavelength of incident light of a coating structure according to an embodiment.

Referring to FIG. 10, when a coating structure according to an embodiment is used, the transmittance of incident light can increase.

When a lens having a metal pattern formed thereon (case 1) is used, the transmittance of incident light is higher than that of when only a conventional lens is used (case 0). When a lens having a metal pattern and a hydrophobic thin film formed thereon (case 2) is used, the transmittance of incident light is higher than that of when only a conventional lens is used (case 0). When the wavelength of the incident light is about 480 nm or more, the transmittance of the incident light when a lens having a metal pattern and a hydrophobic thin film formed thereon (case 2) may be higher than that of the incident light when a lens having a metal pattern formed thereon (case 1). When the wavelength of the incident light is about 480 nm or less, the transmittance of the incident light when a lens having a metal pattern and a hydrophobic thin film formed thereon (case 2) may be lower than that of the incident light when a lens having a metal pattern formed thereon (case 1).

Figures 11 to 13 are graphs showing the transmittance of incident light according to the incident angle of the coating structure according to the embodiment.

Figure 11 is a graph showing the change in transmittance depending on the angle of incidence of incident light when the incident light has a wavelength of 650 nm in the red wavelength region, Figure 12 is a graph showing the change in transmittance when the incident light has a wavelength of 430 nm in the blue wavelength region, and Figure 13 is a graph showing the change in transmittance when the incident light has a wavelength of 540 nm in the green wavelength region.

Referring to FIGS. 11 to 13, when using a coating structure according to an embodiment, the decrease in transmittance as the incident angle of incident light increases can be reduced.

Referring to FIGS. 11 to 13, when a lens formed with a metal pattern and a hydrophobic thin film is used (case 2), the difference in transmittance (d2) depending on the difference in the incident angle of incident light (0˚ to 60˚) may be smaller than the differences in transmittance (d0, d1) depending on the difference in the incident angle of incident light (0˚ to 60˚) when only a conventional lens is used (case 0) and when a lens formed with a metal pattern is used (case 1).

Although the above has been described with reference to examples, these are merely examples and do not limit the present invention. Those skilled in the art will appreciate that various modifications and applications not exemplified above are possible without departing from the essential characteristics of the present invention. For example, each component specifically shown in the examples can be modified and implemented. In addition, differences related to such modifications and applications should be interpreted as being included in the scope of the present invention defined in the appended claims.

Claims (10)

substrate; A first thin film disposed on the substrate; A second thin film disposed on the first thin film; comprising a metal pattern protruding on the substrate; The metal pattern is a coating structure that penetrates the first thin film and a part of the second thin film. In the first paragraph, The first thin film and the second thin film overlap in the first direction, A coating structure in which the first direction is the incident direction of the optical signal and is perpendicular to the first thin film and the second thin film. In the second paragraph, The first thin film includes a first surface and a second surface disposed with the first surface, The above substrate includes an incident surface onto which the optical signal is incident, A coating structure in which the first surface and the incident surface are in contact with each other. In the third paragraph, A coating structure in which the metal pattern is arranged on the incident surface and protrudes in the first direction through the second surface. In the first paragraph, The above first thin film is a coating structure having a refractive index of 1.3 to 3.0. In paragraph 5, The above first thin film is a coating structure including a metal oxide. In Article 6, The above first thin film is a coating structure including TiO2, ZnO or Al2O3. In the second paragraph, A coating structure in which the thickness of the first thin film in the first direction is 0.1 to 0.7 times the height of the metal pattern in the first direction. In Article 8, A coating structure in which the height of the metal pattern in the first direction is smaller than the sum of the thicknesses of the first thin film and the second thin film in the first direction. In the first paragraph, The second thin film is a coating structure having a refractive index of 1.2 to 1.4.

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