KR102025984B1 - Mirror for adjusting light transmittance - Google Patents

Abstract

A highly reliable variable transmission mirror is proposed, which is environmentally friendly and can be manufactured at low cost. Variable transmittance mirror according to the present invention is a variable transmittance mirror including a liquid crystal color change unit according to the applied voltage; And a reflector including a first multilayer reflective film reflecting a portion of incident light and a second multilayer reflective film reflecting a remainder of incident light.

Description

Transmittance variable mirror {MIRROR FOR ADJUSTING LIGHT TRANSMITTANCE}

The present invention relates to a variable transmission mirror, and more particularly, to a highly reliable variable transmission mirror that is environmentally friendly and can be manufactured at low cost.

Electrochromic mirrors are widely applied to ski goggles, sunglasses, vehicle smart mirrors to prevent glare from the driver, or light transmittance control windows. Smart mirror for cars is a mirror applied to the room mirror or side mirror of the vehicle to protect the eyesight of the driver and prevent glare from the strong light from the rear when driving at night. Doing.

Goggles and sunglasses mainly implement a discoloration mirror using photochromic material. Photochromic material has an advantage that it is easy to apply, but it is difficult to apply to a smart mirror for a vehicle because of a slow reaction speed. Accordingly, the smart mirror for a vehicle is mainly implemented with an ECM (Electrochronic mirror) technology.

The conventional commercial ECM is filled with an electrolytic solution mixed with an electrochromic material in two thick glass substrates on which transparent electrodes are formed, and has a structure that discolors by applying electrodes to both substrates. Since ECM technology controls permeability through redox reactions, there is a problem that performance decreases due to material denaturation and deterioration according to the number of repetitions. In addition, since a thick glass is used and the mirror surface is formed by plating, depositing, or painting metal on the opposite side of the electrode, there is a limitation in implementing the shape.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a highly reliable variable transmittance mirror that is environmentally friendly and can be manufactured at low cost.

Variable transmittance mirror according to an embodiment of the present invention for achieving the above object is a color change unit in accordance with the applied voltage, including the liquid crystal; And a reflector including a first multilayer reflective film reflecting a portion of incident light and a second multilayer reflective film reflecting a remainder of incident light.

The color change part may include a first transparent electrode, a liquid crystal layer, and a second transparent electrode.

The first multilayer reflective film may be located on one surface of the discoloration part, and the second multilayer reflective film may be located on the other surface of the discoloration part.

The first multilayer reflective film and the second multilayer reflective film may be located on one surface of the discoloration part.

The liquid crystal may be a cholesteric liquid crystal.

If the liquid crystal has a planar structure, color can be exhibited.

If the liquid crystal has a homeotropic structure, it may exhibit a mirror image.

If a liquid crystal has a focal conic structure, it can show a haze phase.

The discoloration part and the reflecting part may be flexible so that the variable transmittance mirror may be flexible.

According to another aspect of the invention, the step of positioning the liquid crystal between the first transparent electrode and the second transparent electrode to form a color change part that changes color in accordance with the applied voltage; And forming a reflector including a first multilayer reflective film reflecting a part of incident light and a second multilayer reflective film reflecting a remainder of the incident light on the discoloration unit.

According to another aspect of the invention, the color change part is changed according to the applied voltage, including the liquid crystal, comprising a first transparent substrate, a first transparent electrode, a liquid crystal layer, a second transparent electrode and a second transparent substrate Discoloration; And a reflector comprising a first multilayer reflective film reflecting a portion of the incident light and a second multilayer reflective film sequentially reflecting the remainder of the incident light, which are positioned on the other surface of the incident surface of the discolored part. Is provided.

According to another aspect of the invention, the step of forming a discoloration portion that changes color according to the applied voltage by positioning the liquid crystal between the first transparent electrode on the first transparent substrate and the second transparent electrode on the second transparent substrate; And forming a reflector by sequentially stacking a first multilayer reflective film reflecting a part of incident light and a second multilayer reflective film reflecting a remainder of incident light on the other surface of the incident surface of the discolored part. A manufacturing method is provided.

According to the present invention, a complicated deposition process is unnecessary by using a multilayer film as a reflector of the variable transmissivity mirror, and a polymer material is used to produce a low cost.

In addition, without using a conventional electrochromic material using a redox reaction, it is possible to vary the transmittance using a liquid crystal, making it possible to manufacture a mirror with high reliability, and because of the voltage difference driving method, it is possible to manufacture a large area device. .

1 is a cross-sectional view of a variable transmittance mirror according to an embodiment of the present invention.
2 is a diagram illustrating light transmission when the cholesteric liquid crystal has a planar structure, and FIG. 3 is a diagram showing light transmission when the cholesteric liquid crystal has a focal conic structure, and FIG. In the case of a meotropic structure, light transmission is shown.
5 is a cross-sectional view of the first multilayer reflective film, and FIG. 6 is a view illustrating light reflection in the first multilayer reflective film and the second multilayer reflective film.
7 is a cross-sectional view of a variable transmission mirror according to another embodiment of the present invention, Figure 8 is a cross-sectional view of a variable transmission mirror according to another embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. In the accompanying drawings, there may be a component having a specific pattern or having a predetermined thickness, but this is for convenience of description or distinction. It is not limited only.

1 is a cross-sectional view of a variable transmittance mirror 100 according to an embodiment of the present invention. The variable transmittance mirror 100 according to the present exemplary embodiment includes color change parts 111, 112, and 113 that change color according to an applied voltage including a liquid crystal; And reflectors 121 and 122 including a first multilayer reflective film 121 that reflects a portion of incident light and a second multilayer reflective film 122 that reflects the remainder of incident light.

The color change parts 111, 112, and 113 change color when a voltage is applied. The color change parts 111, 112, and 113 include the liquid crystal layer 111, and the liquid crystal layer 111 includes a liquid crystal that exhibits optical anisotropy, and thus, color may be changed due to the change in optical characteristics according to application of voltage.

In the present invention, the liquid crystal layer 111 may include a cholesteric liquid crystal. A cholesteric liquid crystal is a liquid crystal in which layered molecules are oriented in a spiral manner like a nematic liquid crystal, and a reflection transmission property of light is controlled according to the spiral pitch. That is, light of a predetermined wavelength band is selectively reflected according to the spiral pitch of the cholesteric liquid crystal molecules. The arrangement of the cholesteric liquid crystals varies depending on whether the voltage is applied and the magnitude of the voltage. The structure of the cholesteric liquid crystals is changed, and the reflection of incident light can be controlled, thereby controlling the transmittance. The change in the transmittance of the variable transmittance mirror 100 according to the structure of the cholesteric liquid crystal will be further described with reference to FIGS. 2 to 4.

The first transparent electrode 112 and the second transparent electrode 113 are positioned on both sides of the liquid crystal layer 111 to apply a voltage to the liquid crystal layer 111. It is preferable that the first transparent electrode 112 and the second transparent electrode 113 use a transparent and conductive material. The first transparent electrode 112 and the second transparent electrode 113 may include a transparent conductive oxide (TCO). For example, the first transparent electrode 112 and the second transparent electrode 113 may include at least one of zinc oxide, indium oxide, tin oxide, and titanium oxide. It may include one.

The variable transmittance mirror 100 according to the present invention includes reflectors 121 and 122 including a multilayer reflective film. The reflectors 121 and 122 include a first multilayer reflective film 121 and a second multilayer reflective film 122, and the first multilayer reflective film 121 is part of incident light incident on the variable transmittance mirror 100. The second multilayer reflective film 122 may reflect the incident light without being reflected. The reflectors 121 and 122 will be further described below with reference to FIGS. 5 and 6.

According to the present invention, since the discoloration parts 111, 112, 113 and the reflecting parts 121, 122 exhibit flexible characteristics, the transmittance variable mirror 100 may be flexible. In particular, since the reflectors 121 and 122 may be implemented as a multilayer reflective film, the reflector 121 and 122 may be a flexible film exhibiting reflective characteristics, so that the variable transmittance mirror 100 may be a flexible device.

The variable transmissivity mirror 100 forms a color change part 111, 112, and 113 that changes color according to an applied voltage by placing a liquid crystal between the first transparent electrode 112 and the second transparent electrode 113. Reflectors 121 and 122 including a first multilayer reflective film 121 reflecting a part of incident light on the discoloration parts 111, 112, and 113 and a second multilayer reflective film 122 reflecting a remainder of incident light. It can be prepared by forming a.

2 is a diagram illustrating light transmission when the cholesteric liquid crystal has a planar structure, and FIG. 3 is a diagram showing light transmission when the cholesteric liquid crystal is a homeotropic structure, and FIG. 4 is a diagram showing a cholesteric liquid crystal. In the case of a focal conic structure, light transmission is illustrated.

When the liquid crystal layer 111 includes a cholesteric liquid crystal, the cholesteric liquid crystal has a planar structure, a homeotropic structure, and a focal conic structure according to an applied voltage.

When voltage is applied to the cholesteric liquid crystal, a planar structure as shown in FIG. 2 is first shown. When light enters a cholesteric liquid crystal having a planar structure, light of a wavelength corresponding to the pitch of the cholesteric liquid crystal is reflected to exhibit color. When a voltage is further applied, the cholesteric liquid crystal has a focal conic structure (FIG. 3), and light incident on the liquid crystal layer 111 is scattered to have a haze without showing a specific color. The variable transmittance mirror 100 may perform an anti-glare function according to the haze of the liquid crystal layer 111 of the focal conic structure.

If a voltage is further applied, the cholesteric liquid crystal exhibits a homeotropic structure, and the liquid crystal layer 111 transmits all the light. Since the cholesteric liquid crystal of the homeotropic structure transmits all incident light, the incident light is reflected by both the first multilayer reflective film 121 and the second multilayer reflective film 122, so that the variable transmittance mirror 100 is a mirror image. Can be represented.

FIG. 5 is a cross-sectional view of the first multilayer reflective film 121, and FIG. 6 is a view illustrating light reflections in the first multilayer reflective film 121 and the second multilayer reflective film 122. In the multilayer reflective film, a structure in which several or hundreds of layers of materials having different refractive indices are stacked, reflection and reinforcement and destructive interference are caused by Bragg's diffraction by the thickness and refractive index difference of each layer. The reflection can be controlled by adjusting the thickness of the multilayer film, the number of layers, and the refractive index.

For example, the multilayer reflective film may reflect only one of P waves and S waves. Therefore, when the first multilayer reflective film 121 and the second multilayer reflective film 122 are implemented to reflect P waves and S waves, respectively, as in the present invention, all the light may be reflected. Referring to FIG. 6, incident light incident on the first multilayer reflective film 121 includes P waves and S waves, and P waves are reflected by the first multilayer reflective film 121. The S wave transmitted through the first multilayer reflective film 121 is reflected by the second multilayer reflective film 122 to reflect all light.

Referring back to FIG. 1, the first multilayer reflective film 121 is positioned on one surface of the discoloration parts 111, 112, and 113, and the second multilayer reflective film 122 is the other surface of the discoloration parts 111, 112, and 113. Located in It will be described on the assumption that the first multilayer reflective film 121 reflects the P wave and the second multilayer reflective film 122 reflects the S wave.

In the variable transmittance mirror 100 of FIG. 1, the first multilayer reflective film 121 is positioned on the side where light is incident. When the cholesteric liquid crystal of the liquid crystal layer 111 has a planar structure, the P wave is reflected and the S wave is transmitted by the first multilayer reflective film 121 incident on the variable transmittance mirror 100. The transmitted S-waves reflect light of the wavelength corresponding to the pitch of the cholesteric liquid crystal in the liquid crystal layer 111 to exhibit color.

When the cholesteric liquid crystal has a focal conic structure, the transmitted S-waves are scattered so that the variable transmittance mirror 100 exhibits a haze phase. On the other hand, when the cholesteric liquid crystal has a homeotropic structure, the transmitted S-waves are transmitted through the liquid crystal layer 111, and are reflected back from the second multilayer reflective film 122, so that all the light has a variable transmittance mirror 100. The reflected mirror image is shown.

7 is a cross-sectional view of a variable transmission mirror 100 according to another embodiment of the present invention, Figure 8 is a cross-sectional view of a variable transmission mirror 100 according to another embodiment of the present invention. In FIGS. 7 and 8, the variable transmittance mirror 100 includes the first multilayer reflective film 121 and the second multilayer reflective film 122 positioned on one side of the discoloration portions 111, 112, 113, 114, and 115. can do. In FIG. 1, the first multilayer reflective film 121 and the second multilayer reflective film 122 are implemented with the liquid crystal layer 111 interposed therebetween. In this case, the cholesteric liquid crystal exhibits a mirror image in the homeotropic structure. In addition, the transmitted S waves may be separated into S waves and P waves again while passing through the liquid crystal layer 111. Thus, the mirror image may not be complete.

In contrast, in FIGS. 7 and 8, the reflection parts 121 and 122 are formed on one side of the discoloration parts 111, 112, 113, 114 and 115, and preferably the discoloration parts 111, 112, 113, 114 and 115. The incident light is positioned on a surface other than the incident surface of the both surfaces to allow the incident light to reach the reflectors 121 and 122 after passing through the liquid crystal layer 111.

Referring to FIG. 7, the variable transmittance mirror 100 of the present exemplary embodiment is a color change part 111, 112, 113, 114, and 115, and includes a first transparent substrate 114, a first transparent electrode, a liquid crystal layer 111, It includes a second transparent electrode and a second transparent substrate 115 and reflecting parts 121, 122 positioned on the other surface of the surface incident incident light of the discoloration portion (111, 112, 113, 114, 115). In the transmittance variable mirror 100 of the present exemplary embodiment, the color change parts 111, 112, 113, 114, and 115 include a first transparent substrate 114 and a second transparent substrate 115. In the variable transmittance mirror 100 of FIG. 1, the first multilayer reflective film 121 and the second multilayer reflective film 122 are positioned at both sides of the color change parts 111, 112, and 113. Since the multilayer film does not exist on the side where incident light from the discoloration parts 111, 112, 113, 114 and 115 is incident, the first transparent substrate 114 may be positioned to protect the liquid crystal layer 111.

The substrate that can be used for the first transparent substrate 114 and the second transparent substrate 115 is not particularly limited as long as it has transparency, and is a transparent inorganic substrate film such as quartz or glass, polyethylene terephthalate (PET), polyethylene Naphthalate (PEN), Polycarbonate (PC), Polystyrene (PS), Polypropylene (PP), Polyimide (PI), Polyethylenesulfonate (PES), Polyoxymethylene (POM), Polyetheretherketone (PEEK) , Any one of a transparent plastic base film selected from the group consisting of polyethersulfone (PES) and polyetherimide (PEI) can be used. When the first transparent substrate 114 and the second transparent substrate 115 are implemented with a transparent plastic film, the transmittance variable mirror 100 may be implemented as a flexible device.

8, the discoloration parts 111, 112, 113, and 114 of the variable transmittance mirror 100 include only the first transparent substrate 114. Since the first multilayer reflective film 121 and the second multilayer reflective film 122 are positioned on the second transparent electrode 113 side, as shown in FIG. 7, the liquid crystal layer 111 does not have to include the second transparent substrate 115. Prepare for physical destruction or damage.

As described above, embodiments of the present invention have been described, but those skilled in the art may add, change, delete, or add elements within the scope not departing from the spirit of the present invention described in the claims. The present invention may be modified and changed in various ways, etc., which will also be included within the scope of the present invention.

100 transmittance variable mirror
111 liquid crystal layer
112 First Transparent Electrode
113 Second Transparent Electrode
114 First Transparent Substrate
115 2nd transparent board
121 1st multilayer reflective film
122 Second Multilayer Reflective Film

Claims (12)

A color change part that changes color depending on an applied voltage including a cholesteric liquid crystal; And
And a reflector including a first multilayer reflecting film reflecting any one of S-wave or P-wave of incident light and a second multilayer reflecting film reflecting a remainder of incident light.
The first multilayer reflective film and the second multilayer reflective film are positioned together on one surface of the discoloration unit so that the reflector can reflect both the S-wave and P-waves that are all incident light. The method according to claim 1,
The discoloration unit includes a first transparent electrode, a liquid crystal layer, and a second transparent electrode. delete delete delete The method according to claim 1,
If the liquid crystal is a planar structure, the color is displayed, characterized in that the variable mirror. The method according to claim 1,
The variable transmittance mirror, characterized in that the liquid crystal is a homeotropic structure showing a mirror image. The method according to claim 1,
The said variable liquid crystal shows a haze phase, if it is a focal conic structure, The variable transmittance mirror characterized by the above-mentioned. The method according to claim 1,
The discoloration unit and the reflecting unit are flexible, and the transmittance variable mirror is characterized in that the flexible mirror is flexible. Placing a cholesteric liquid crystal between the first transparent electrode and the second transparent electrode to form a color change part that changes color according to an applied voltage; And
Forming a reflector including a first multilayer reflective film reflecting any one of S-wave or P-wave of incident light and a second multilayer reflective film reflecting the remainder of incident light on the discoloration unit; As a manufacturing method,
The first multilayer reflective film and the second multilayer reflective film is positioned on one surface of the discoloration portion so that the reflector can reflect both the S-wave and P-waves that are all incident light, characterized in that the variable mirror manufacturing method. delete Positioning a cholesteric liquid crystal between the first transparent electrode on the first transparent substrate and the second transparent electrode on the second transparent substrate to form a color change part that changes color according to an applied voltage; And
On the other side of the surface where the incident light of the discoloration part is incident, the first multilayer reflective film which reflects either the S-wave or the P-wave of the incident light and the second multilayer reflective film which reflects the rest of the incident light are located together on one surface of the discoloration part. Laminating sequentially so as to form a reflector to reflect all the S-waves and P-waves that are all the incident light; Transmittance variable mirror manufacturing method comprising a.

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