KR20190080285A - Optical Structure for Improving Sunscreen Performance and Manufacturing Method thereof - Google Patents

Abstract

According to the present invention, an optical structure is formed by alternately stacking a high refractive layer and a low refractive layer on a substrate, and comprises first and second optical multilayer films including a near infrared shielding layer which reflects near infrared rays wherein the first and second optical multilayer films are configured so that 1-1^th, 1-2^th, 1-3^th layers or 2-1^th, 2-2^th, 2-3^th layers have different geometrical thicknesses. The 2-3^th layer is not configured as necessary. Therefore, an optical multilayer film according to an embodiment of the present invention can have sufficient reflection performance against near infrared rays and have limited reflection performance against visible light so as to have sufficient shielding performance against sunlight, thereby providing a user with sufficient visible light transmission and improved infrared shielding performance.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical structure for improving sunlight shielding performance and a manufacturing method thereof,

The present invention relates to an optical structure and a method of manufacturing the same, and more particularly, to an optical structure for improving the shielding ability against sunlight by adjusting a transmission / reflection ratio at a certain wavelength among visible light and a method of manufacturing the same.

Recently, various technologies have been developed to implement functions in window systems. These technologies are collectively referred to as smart windows. A window for applying infrared shielding technology to increase the efficiency of energy use through control of incident light, a low radiation window for controlling the radiation characteristics of the glass formed in the window, a multiple glass / vacuum window for improving the thermal conductivity, Electrochromic window (EC) for realizing usage efficiency and protecting privacy Suspended Particle Display, SPD; Various types of technologies such as Polymer Dispersed Liquid Crystal (PDLC), Thermal Chromic (TC), self-cleaning windows capable of preventing or eliminating window contamination, and display windows are being developed. Among these windows, infrared shielding technology is one of the fields to improve energy efficiency of buildings. Infrared shielding technology, which is classified as a passive device, has been developed in various forms over a long period of time and can be supplied at a low price, making it familiar to users.

 Many methods for implementing such an infrared shielding function have already been proposed. The most popular technologies are absorption-type devices that use dyes, nanoparticles, or oxides with infrared absorption properties. It is the most well known technology field because various methods are implemented according to the manufacturer and the manufacturing process can be configured relatively inexpensively. However, when the infrared ray shielding is implemented by the absorption method, the absorbed energy is radiated in the form of radiation or the surrounding air, so that it has a limitation in realizing a high shielding performance. Further, since the energy absorbed over a long period of time acts as a cause for changing the characteristics of the shielding material, it is not easy to secure reliability. In addition, when a shielding performance through absorption is required, it is applied as a method of increasing the absorption amount when a higher level of shielding performance is required, which causes deterioration of transparency of visible light.

 In addition to the absorption method, what is popular is a method of realizing reflection of light by using metal or transparent conductive material. The reflection type infrared ray shielding technology using such a specific material may have a low reflection characteristic due to low stability of oxidation of the reflection material, and thus, an improved structure is required to prevent the reflection property. Techniques for implementing a reflective function using metals such as silver or silver compounds known as soft low-e constitute double or triple glasses for the purpose of improving thermal conductivity and oxidation inhibition, Place them between the spaced glass so that the system is configured to prevent oxidation. However, restraining the change of characteristics through the configuration of such a system is easy to apply the technology in the case of constructing a new building, but it is a factor that deteriorates the accessibility of the related technology in the renovation of the star building. In some technologies, the reflection layer is placed between two polymers to prevent the change of characteristics, but the characteristics of the polymer which changes the moisture permeability according to the temperature change are overlooked. When the temperature and humidity are high or the seasonal change is severe, . In addition, due to exposure of the side surface of the polymer according to the construction method, there is a limit in suppressing the characteristic change in the inner side from the exposed outer side. In order to improve reflection characteristics, a product which implements reflection by using such a metal or metal oxide has a problem of decreasing the transmittance of the visible light because it increases the thickness. In addition, since the electromagnetic shielding space is formed, when the reflection technology is applied, the communication is blocked inside the automobile or the commercial building.

 A method of improving the limitations of such a shielding technique is a reflection-type shielding technique using an optical multilayer film. The infrared shielding technology implemented with the optical multilayer film facilitates securing various reflection characteristics and visible light transmission characteristics by controlling the thickness / number of layers constituting the multilayer film and the characteristics of the constituent materials. It is essential that the reflection technique of the optical multilayer film system alternately laminate the material having the difference in refractive index of at least two kinds of the thickness of the function to the wavelength to be controlled. The commercially available optical multilayer reflection technique has the same principle of reflection but can be classified by the material to be applied. Japanese Patent PCT / JP2003 / 002073, which is well known, and Patent No. 4461532, which has been annulled by Shokken Co., Such a technique is produced by laminating / laminating polymers having different refractive indices and stretching at a high temperature so as to have a specific thickness. The optical film technology of the laminated type is easy to realize a predetermined thickness required through stretching but limits the ability to provide improved performance by controlling the reflection wavelength by changing the refractive index and the thickness of the constitution, and in order to improve the near infrared ray shielding property, Layer, it is possible to implement the performance. Unlike this technology, it is relatively easy to select a material having various refractive indexes in an optical multilayer film implemented through a thin film. US registration (disappearance) The technique described in patent US4461532 (1984-07-24) controls the thickness of the layer to be formed at the outermost layer to control ripple (coloration) / 8 < / RTI > thick. However, when the optical structure is fabricated using the proposed technique, not only the transmittance of the visible light but also the transmittance of the infrared light are increased, thereby deteriorating the shielding performance of the sunlight. In addition, JP 05076897 suggests a method of forming an additional layer of 5 to 40 nm to improve the infrared reflection characteristic, but the proposed method also has a problem of lowering the efficiency at the reflection center wavelength. The technique disclosed in KR 10-2015-0113087 recently discloses a technique of adjusting color by adjusting the thickness of the transmitted light and the reflection wavelength, but the proposed technique maximizes the reflection of the solar near-infrared rays But it has a problem in that it can not control the reflection of near infrared rays because it implements color by changing the center of transmission and reflection wavelength.

  In summary, in the conventional technology of absorbing and reflecting metal, the transmittance of the visible light ray is 75% or more and the infrared ray shielding ability can not be satisfactorily achieved. In the optical multilayer infrared ray reflection technique, But there is a limit to improvement of the infrared shielding ability.

US registered patent US4461532 PCT / JP2003 / 002073 Korean Patent Publication No. 10-2015-0113087

In order to secure a technology capable of reducing the incident ratio of solar energy to realize a transmittance of a certain level or higher with respect to visible light, the present invention can improve the shielding performance of solar energy by controlling transmission and reflectance of visible light at a specific wavelength And a method for manufacturing the optical structure.

By controlling the transmission reflection characteristics for a particular wavelength, the sunlight shielding performance of the optical structure used for infrared shielding purposes can be improved. It has a high energy distribution in the visible region of the sun and has a high energy of visible light having a large energy range of 380 to 750 nm and a reflection of less than 450 nm and a wavelength of 700 nm or more and a transmission and reflection ratio of 750 nm to 1000 nm in the near- As shown in FIG. In addition, by limiting the reflection in the range of 450 ~ 700nm of the visible light region, it is possible to control the incident ratio of solar energy. The transmission and reflection characteristics are controlled by changing the thicknesses of the low refraction layer and the high refraction layer of the optical structure applied to the geometrical optical thickness of / 4 to have different values. Also, it is possible to change or remove the thickness of / 8 applied to the outermost layer on the basis of the substrate in order to suppress the ripple (coloring).

 The technique embodied in the present patent is based on the fact that the detection ability for the difference of the change of the human eye with respect to the wavelength of 450 nm or less or 700 nm or more is reduced in comparison with the wavelength around 550 nm. The difference in the described wavelengths is lower than the detection level for the displacement at 550 nm, so even if a reflection of several tens of percent is achieved, this is perceived as a few percent difference level. By using this, the actual ratio of solar energy incident on solar energy can be reduced, while the transmittance of human eyes can be realized with a high optical multilayer film.

  Also, by reflecting the range of 700 nm or more, the color realized in red can reflect other wavelengths in the range of 380 to 700 nm, so that the color of the color realized in red can be changed to another color. Reflection in an acceptable range for the visible light region through this technique makes it possible to provide a specific color through transmission and reflection to the device to which the optical structure for infrared shielding purposes is applied.

According to the optical multilayer film according to the embodiment of the present invention, it is possible to realize appropriate reflection for the visible light region while maintaining a highly reflective function for the near-infrared region. This allows the visible light transmittance of the infrared reflective optical structure used for solar shielding purposes to be maintained at a certain level and to improve the solar shielding performance. Accordingly, the window to which the proposed technique is applied can provide a more comfortable indoor environment through the improved infrared reflection and can provide an improved view through the high transmittance.

1 is a schematic view of an optical structure for infrared reflection to be proposed in the present invention.
FIGS. 2 to 4 are results of spectral analysis and layer thicknesses of the optical structure of the embodiment of the present invention
Figs. 5 and 6 are the result of spectral analysis and thickness of the optical structure of the comparative example shown before the present invention

Hereinafter, embodiments of the present invention will be described in detail. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of other various forms of implementation, and that these embodiments are provided so that this disclosure will be thorough and complete, It is provided to let you know completely.

The present invention is to provide a method for improving the shielding property of indoor light to sunlight by having a limited reflection function for visible light while maintaining an appropriate reflection function for near infrared rays among sunlight.

The optical multilayered film according to the first comparative example has a structure in which the substrate / the first high refraction layer (TiO 2) / the first low refraction layer (SiO 2) / the second high refraction layer (TiO 2) / the second low refraction layer (SiO 2) / the third high refraction layer The thickness of the first, second and third high refractive index layers 21a, 21b and 21c is 100 nm and the thicknesses of the first and second low refractive layers 22a and 22b, And the third low refractive index layer 22c as the uppermost layer is 80 nm which is 0.50 to 0.55 of the first and second low refractive index layers 22a and 22b.

The optical multilayer film according to the second comparative example has a structure in which the substrate / first high refraction layer (TiO2) / first low refraction layer (SiO2) / second high refraction layer (TiO2) / second low refraction layer (SiO2) / third high refraction layer TiO 2) / third low refractive index layer (SiO 2), the thicknesses of the first, second and third high refractive index layers are 97.5 nm, the thicknesses of the first and second low refractive index layers are 102.5 nm, 3 low refraction layer is 77.5 nm.

The optical multilayered film 100 according to the first embodiment has a structure in which the substrate / the first high refraction layer (TiO2) / the first low refraction layer (SiO2) / the second high refraction layer (TiO2) / the second low refraction layer (SiO2) The first and second high refractive index layers 21a, 21b and 21c are formed of a high refractive index layer (TiO2) having a thickness of 105/95 / 105nm and first and second low refractive layers 22a and 22b, Is 110 nm and 150 nm. The top layer / 8 layers that existing technologies introduced for the purpose of color removal (ripple) removal are excluded from the configuration.

The optical multilayered film 100 according to the second embodiment comprises a substrate 1, a first high refraction layer (TiO 2) / a first low refraction layer (SiO 2) / a second high refraction layer (TiO 2) / a second low refraction layer (SiO 2) And the first and second high refractive index layers 21a, 21b and 21c are 110/88/110 nm thick and the first and second low refractive index layers 22a and 22b are made of a high refractive index layer (TiO2) Is 145 nm.

The optical multilayered film 100 according to the third embodiment includes a substrate 1, a first high refractive index layer (TiO 2) / a first low refractive index layer (SiO 2) / a second high refractive index layer (TiO 2) / a second low refractive index layer (SiO 2) And the first and second high refractive index layers 21a, 21b and 21c are 100/110/110 nm thick and the first and second low refractive layers 22a and 22b are made of a high refractive index layer (TiO2) Is 160/120 nm.

rescue High refractive index layer thickness (nm) Thickness of low refraction layer (nm) Top Thickness (nm) Comparative Example 1 Substrate / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ TiO ₂ 100 nm SiO ₂ 160 nm SiO ₂ 80 nm Comparative Example 2 Substrate / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ TiO ₂ 97.5 nm SiO ₂ 102.5 nm SiO ₂ 77.5 nm First Embodiment Substrate / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ TiO ₂
105/95 / 105nm SiO ₂
110 / 150nm - none Second Embodiment Substrate / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ TiO ₂
110/88 / 110nm SiO ₂
145 / 145nm - none Third Embodiment Substrate / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ TiO ₂
100/110 / 110nm SiO ₂ 160/120 nm - none

rescue  ~ 450 nm reflectance (%) Standard visible light wavelength transmittance (550 nm) (%) Visible light reflectance
(380 to 750 nm) (%) Near infrared reflectance
(750 to 1000 nm) (%) Solar Energy Ratio
(350 ~ 2500 nm) (%) Comparative Example 1 Board/ TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ 11.2 96.8 8 61.6 61.1 Comparative Example 2 Board/ TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ 36.14 96.8 23.6 62.4 57.0 First Embodiment Board/ TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ 37.3 90.5 16.2 74.4 54.9 Second Embodiment Board/ TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ 31.9 91.6 13.5 72.4 54.8 Third Embodiment Board/ TiO ₂ / SiO ₂ / TiO ₂ / SiO ₂ / TiO ₂ 40.7 94.7 14.8 69.1 54.2

For the visually open environment of the window of the building, and for securing the vision for safety in transportation equipment, the transmittance in the visible light region should be at least 75%. In addition, the reflection ratio of the visible ray region varies depending on the region, but it may cause glare to the external observer due to reflection, so a low value is required to prevent the reflection, so it should be less than 20%. As can be seen in the first comparative example, the transmittance of 90% or more is ensured and the reflectivity for 750 nm to 1000 nm in the near infrared region is only 61.6%. This causes 61.1% of solar energy to enter the room.

 Also, in the second comparative example in which the color is improved by improving the reflection, the reflection of visible light reaches 23%, but 57% is introduced into the room of solar energy. The application of this technique means that the observer is inconvenienced by reflection, but does not achieve sufficient shielding performance.

 As can be seen in the first embodiment, the reflectance in the entire visible light region is 16.2%, which is a result of including wavelengths of 450 nm or shorter and 700 nm or shorter in visible sensitivity, and 90% or more at wavelengths around 550 nm, It is possible to realize transmittance. Also, as can be seen, it has a shielding ability that reflects near-infrared rays of 74.4%. In the first embodiment, only a part of infrared rays and visible light are reflected, so that only 54.9% of the solar energy flows into the room.

 In the case of the second embodiment, when the total reflectance in the visible light region is reduced so that the transmissivity of 90% or more of the visible light at a wavelength of around 550 nm is sufficiently reflected, the wavelength of 450 or less and the near infrared light of 750 to 1000 nm are sufficiently reflected, Energy incidence ratio can be implemented.

 As in the first, second and third embodiments, it is possible to increase the reflection ratio of 450 nm or less and sufficiently realize the reflectance of the solar near-infrared rays. Further, the application of this technology can increase the reflection ratio of the total solar energy to 45% It is possible to keep the transmittance at 90% or more at a wavelength around 550 nm where the eyes have high visibility. The application of this technology provides a high visual open environment and enables the shielding performance against solar near infrared rays to be improved.

The optical multilayer thin film was designed using an optical simulator, Essential Maclaud, and a multilayer optical multilayer film was fabricated by using in - line sputter and roll sputter. Transmission and reflection of visible light and infrared rays were measured using lamda 1050, and incident ratio of solar energy was calculated using KS L 2514.

100: Optical multilayer film
10: substrate
20: near infrared ray shielding layer
21a, 21b, 21c: high-refraction layer
22a, 22b, 22c: a low refractive layer

Claims (11)

 An optical structure having an infrared ray reflection function, wherein the optical structure is configured to reflect a part of visible light while reflecting the near-infrared region of the sun.   The optical structure according to claim 1, wherein the optical structure alternately stacks a high refractive index material and a low refractive index material.   The optical structure according to claim 2, wherein the optical structure uses a material having a refractive index of 1.9 or higher as a high refractive index material.   The optical structure according to claim 2, wherein the optical structure uses a refractive index of 1.56 or less as a low refractive material.   The optical structure according to claim 2, wherein the optical structure has a thickness of the high refraction layer or at least one of different values of the low refraction layer in each of the high refractive index layer and the low refraction layer.   The optical structure according to claim 1, wherein the optical structure is composed of four layers, five layers, six layers, or seven layers. The optical structure according to claim 1, wherein the optical structure has a first reflection center in a wavelength range of 750 to 950 nm of near-infrared light. 7. The optical structure according to claim 7, wherein the first near-infrared ray having a wavelength in the range of 750 to 950 nm has a reflectance of 60% or more. The optical structure according to claim 1, wherein a part of the reflected visible light includes 380 to 450 nm and 700 to 750 nm. The optical structure according to claim 9, wherein the optical structure has an average reflectance of 30% or more on the visible light in the range of 380 to 450 nm or less. The optical structure according to claim 9, wherein the 700 to 750 nm range has an average reflectance of 20% or more.

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