JP2005003895A - Reflection mirror - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a reflection mirror having the large difference of light transmittance between at the time of coloring and at the time of non-coloring and making the color of reflected light at the time of non-coloring white or a color near to white. <P>SOLUTION: In the reflection mirror 10, a gold coating film 26 whose thickness is 10nm is formed on the side of the ion conductive coating film 24 of a conductive reflection film 16 formed of aluminum or the like, and is made to react on a hydroxyl group produced in electrolysis. Thus, the difference of the transmittance of the reflected light between in the case a reduction colored coating film 22 is colored and in a state where the coloring is released is made large. Besides, the light is reflected by the reflection film 16, and the gold coating film 26 is thin to such an extent that the light can be transmitted. Therefore, influence exerted on the reflected light by the color of gold itself is effectively reduced. Then, the color of the reflected light is made white or the color nearer to white. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a reflecting mirror that reflects light, and more particularly to a reflecting mirror that is suitable for a door mirror, an inner mirror, or the like that is attached to a vehicle.
[0002]
[Prior art]
The vehicle is provided with a so-called door mirror (also referred to as an outer view mirror) for confirming the left and right rear sides.
[0003]
Confirmation of the rear of the vehicle with such a reflecting mirror is performed by confirming a reflected image by the reflected light from the reflecting mirror. At night, for example, the light of the headlight of the following vehicle is reflected on the reflecting film. It is possible to confirm that there is a vehicle traveling backward by being reflected at.
[0004]
However, at night or the like, the light from the headlight is sufficiently bright with respect to the surrounding brightness, and the reflected light from the reflecting mirror is dazzling. For this reason, a reflection mirror having an electrochromic coating provided between a glass substrate and a reflection film may be used for a door mirror of a vehicle in recent years (see Patent Documents 1 to 3 as an example).
[0005]
The electrochromic film used in such a reflector includes a transparent electrode film formed of ITO (an oxide of an alloy of indium and tin) on the back surface of a glass substrate. Further, on the back side of the transparent electrode film (on the opposite side of the glass substrate of the transparent electrode film), an oxidized colored film formed of tin oxide or the like, a reduced colored film formed of tungsten oxide, silicon dioxide or pentoxide. Various films (thin films) of ion conductive films formed of tantalum or the like are provided in a laminated state. Furthermore, a conductive reflective film formed of aluminum or the like is provided on the opposite side of these various films (thin films) to the transparent electrode film.
[0006]
In the electrochromic film having the above configuration, when a voltage is applied between the transparent electrode film and the conductive reflective film, a reversible coloring reaction occurs in the oxidized colored film and the reduced colored film. This coloring reaction reduces the light transmittance in the oxidized colored film and the reduced colored film, reduces the amount of reflected light in the conductive reflective film, and improves the antiglare property.
[0007]
In addition, when a reverse voltage is applied between the transparent electrode film and the conductive reflective film, the colored state of the oxidized colored film and the reduced colored film is released, and the light transmittance reduced by the coloring is restored. .
[0008]
On the other hand, as another example of the electrochromic coating, Non-Patent Document 1 below discloses a configuration in which a gold thin film is used as an electrode coating corresponding to a conductive reflective film. When such a gold thin film is used as an electrode film, moisture contained in the ion conductive film is electrolyzed when a voltage is applied when coloring the reduced coloring film, and the resulting hydroxyl group is converted into a gold thin film gold. The gold thin film is slightly colored.
[0009]
[Patent Document 1]
JP-A-7-125575 [Patent Document 2]
Japanese Patent Laid-Open No. 2000-2895 [Patent Document 3]
Japanese Utility Model Publication No. 6-84437 [Non-Patent Document 1]
Scientific paper "Soviet Electrochemistry", published in 1996, Vol. 28, No. 10, pp. 1186 to 1190 "Electrochromic mirrors as solid state ionic device"
[0010]
[Problems to be solved by the invention]
In the case of an electrochromic film using such a gold thin film, the light transmittance when uncolored is about 75.7%, whereas the light transmittance when colored is about 7.2%. There is an advantage that there is a large difference in light transmittance between time and non-coloration.
[0011]
However, when a gold thin film is used for the conductive reflective film, there is a drawback that the color of the reflected light, particularly the non-colored reflected light, is tinged with yellow, which is the color of gold itself.
[0012]
In view of the above facts, the present invention provides a reflector that has a large difference in light transmittance between colored and non-colored, and that reflects reflected light in white or a color close to white. Is the purpose.
[0013]
[Means for Solving the Problems]
The reflector according to the first aspect of the present invention is substantially transparent or a substrate that transmits light of a predetermined wavelength and a substantially transparent substrate that is formed on the back side of the substrate and has conductivity and can transmit light. A transparent electrode film, a reduction-colored film formed on the opposite side of the substrate through the transparent electrode film, and colored by a reversible electrochemical reaction when a voltage is applied, and the reduction-colored film through the reduction-colored film An ionic conductive coating formed on the opposite side of the transparent electrode coating, and a gloss that is formed on the opposite side of the reduced conductive coating of the ionic conductive coating and capable of reflecting light incident from the substrate side. A reflective film having a thickness capable of transmitting light from the substrate side and the reflective film side, provided on the ion conductive film side of the reflective film, and caused by the electrochemical reaction A gold film that reacts with a hydroxyl group, and Original colored coat, releases a colored or said coloring the reduction coloring film by applying the ion-conductive coating, and a voltage in the stacking direction of said gold film, is characterized by.
[0014]
In the reflecting mirror according to the first aspect of the present invention, incident light incident from the surface side of the substrate is transmitted through the substrate, the transparent electrode coating, the reduced colored coating, the ion conductive coating, and the gold coating to the reflecting coating. It reaches and is reflected by the reflective film. The reflected light reflected by the reflective film passes through the gold film, the ion conductive film, the reduced colored film, the transparent electrode film, and the substrate.
[0015]
Therefore, when the reflecting mirror according to the present invention is a mirror for confirming the rear of the vehicle such as an inner mirror or a door mirror of the vehicle, the rear of the vehicle can be confirmed by visually recognizing the reflected image formed by the reflected light.
[0016]
Further, in the reflecting mirror according to the present invention, when a voltage is applied between the transparent electrode film and the electrode film provided separately from the reflection film or the reflection film, a reversible electrochemical reaction occurs, and this electrochemical reaction occurs. The hydrogen ions generated during the reaction react with the reduced colored film to color the reduced colored film, and the hydroxyl group reacts with gold constituting the gold film. The light transmittance in the reduced colored coating is reduced by the coloring of the reduced colored coating.
[0017]
Thereby, for example, when the reflecting mirror is a vehicle rear-viewing mirror as described above, the reflected light can be suppressed by setting the reduced colored coating in a colored state. For this reason, when the headlight of the vehicle behind and the like is too bright, the antiglare property can be improved by suppressing the reflected light by setting the reduced coloring film in a colored state.
[0018]
On the other hand, the hydroxyl group generated by the electrochemical reaction as described above reacts with the gold of the gold coating, but in the present reflector, the thickness of the gold coating is sufficiently thick to transmit light (for example, the gold coating). The thickness is 5 nm or more and 20 nm or less, preferably 10 nm), and a reflective film is additionally provided on the back side of the gold coating (on the side opposite to the substrate). That is, in this reflector, the gold film is basically required to react with a hydroxyl group, and it is not required to reflect light on the gold film. Therefore, by sufficiently reducing the thickness of the gold coating as described above, the proportion of light in the wavelength range of the yellowish color that is the color of gold itself in the reflected light can be extremely reduced, and as a result, the reflected light Can be white or close to white.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
<Configuration of the present embodiment>
FIG. 1 is an enlarged sectional view schematically showing the structure of a reflecting mirror 10 according to an embodiment of the present invention.
[0020]
As shown in this figure, the reflecting mirror 10 includes a glass substrate 12 as a substrate. An electrochromic coating 14 is provided on the back surface of the glass substrate 12. The electrochromic film 14 includes a reflective film and a conductive reflective film 16 as an electrode film. The conductive reflective film 16 is made of, for example, aluminum (Al), chromium (Cr), palladium (Pd), rhodium (Rh), platinum (Pt), or the like. When the conductive reflective film 16 is made of, for example, aluminum (Al), chromium (Cr), or rhodium (Rh), the thickness thereof is set to about 50 nm.
[0021]
Since the conductive reflective film 16 is made of the above-described metal, at least the surface on the glass substrate 12 side has sufficient gloss, and the light incident from the glass substrate 12 side is reflected with high reflectivity and conductive. It is connected to the power supply 18 via a control circuit (not shown) constituted by a switch or an optical sensor, and further a CPU (ECU) or the like.
[0022]
A transparent electrode film 20 constituting the electrochromic film 14 is formed between the conductive reflective film 16 and the glass substrate 12. The transparent electrode film 20 is made of an oxide of an alloy of indium and tin, so-called “ITO”, and has a thickness of about 150 nm. The transparent electrode film 20 is basically substantially transparent and conductive, and is connected to the power source 18 via a switch or photosensor, and a control circuit (not shown) constituted by a CPU (ECU) or the like. ing.
[0023]
Further, a reduced colored coating 22 constituting the electrochromic coating 14 is formed on the opposite side of the transparent electrode coating 20 from the glass substrate 12. In the present embodiment, the reduced coloring film 22 is made of tungsten trioxide (WO ₃ ) and has a thickness of about 500 nm. The reduction-colored coating 22 is basically substantially transparent, but causes a reversible electrochemical reaction with hydrogen ions, and is colored in a blue color when the hydrogen ions are combined. Further, when the binding of hydrogen ions is released in this colored state, the coloring is released and the structure becomes transparent again.
[0024]
Further, an ion conductive coating 24 constituting the electrochromic coating 14 is formed on the opposite side of the reduced coloring coating 22 from the transparent electrode coating 20. In the present embodiment, the ion conductive coating 24 is basically formed of silicon dioxide (SiO ₂ ) or magnesium fluoride (MgF ₂ ) and contains moisture.
[0025]
In the present embodiment, the thickness of the ion conductive film 24 is set to approximately 200 nm when the ion conductive film 24 is formed of silicon dioxide. On the other hand, when the ion conductive film 24 is formed of magnesium fluoride and the conductive reflective film 16 is formed of chromium, the thickness of the ion conductive film 24 is set to about 410 nm. When the conductive film 24 is formed of magnesium fluoride and the conductive reflective film 16 is formed of rhodium, the thickness of the ion conductive film 24 is set to approximately 250 nm.
[0026]
A gold coating 26 is formed between the ion conductive coating 24 and the conductive reflective film 16. The gold coating 26 is made of gold (Au), and the thickness thereof is a thickness that can sufficiently transmit light, and is numerically 5 nm or more and less than 20 nm, preferably 10 nm (note that In the present embodiment, the thickness of the gold coating 26 is set to 10 nm).
[0027]
<Operation and effect of the present embodiment>
Next, the operation and effect of the reflecting mirror 10 will be described.
[0028]
In the reflecting mirror 10, the light transmitted through the glass substrate 12 enters the conductive reflecting film 16, and is reflected at an angle corresponding to the incident angle at this time and the reflectance of the conductive reflecting film 16, and again, The light passes through the glass substrate 12 and exits from the surface side of the glass substrate 12 to the outside. Therefore, when the reflecting mirror 10 is applied to a door mirror of a vehicle, the state on the substantially vehicle rear side can be confirmed by visually recognizing the reflected image formed by the reflected light.
[0029]
Further, in the present reflecting mirror 10, when a switch (not shown) is operated or the optical sensor senses light having a predetermined luminance or higher, the control means applies a predetermined voltage from the conductive reflective film 16 to the transparent electrode film 20. . By applying this voltage, the water contained in the ion conductive film 24 is electrolyzed to generate hydrogen ions (H ⁺ ) and hydroxyl groups (OH ⁻ ).
[0030]
The hydrogen ions generated in this way move to the reduced colored coating 22 side and reach the reduced colored coating 22 to be bonded to tungsten trioxide constituting the reduced colored coating 22. On the other hand, the hydroxyl group moves to the gold coating 26 side and reaches the gold coating 26 to bond to the gold constituting the gold coating 26.
[0031]
Tungsten trioxide (WO ₃ ) constituting the reduced colored coating 22 becomes H _X WO ₃ when hydrogen ions are bonded. As a result, the reduced colored coating 22 that has been substantially transparent until then is colored substantially blue, and the light transmittance in the reduced colored coating 22 is reduced.
[0032]
Therefore, when strong light is incident on the reflecting mirror 10, by applying a predetermined voltage between the conductive reflective film 16 and the transparent electrode film 20 so as to reduce the light transmittance of the reduced colored film 22, The brightness of the reflected light is reduced. For this reason, if such a reflecting mirror 10 is used for a door mirror or an inner mirror for confirming the rear of the vehicle, the reflected light when the reflecting mirror 10 reflects light from the headlight of the rear vehicle at night or the like. Can reduce brightness and improve anti-glare properties.
[0033]
On the other hand, when a switch (not shown) is operated in the colored state of the reduced colored coating 22 or when the light sensor stops detecting light of a predetermined luminance or higher, the conductive reflection from the transparent electrode coating 20 is performed by the control means. A predetermined reverse voltage is applied to the film 16. Thereby, the bond of hydrogen ions in the reduced coloring film 22 is released, and the bond of the hydroxyl group in the gold film 26 is released. Thereby, the reduction coloring film 22 becomes substantially transparent again, the light transmittance of the reflecting mirror 10 returns to the state before the coloring of the reducing coloring film 22, and the light transmittance in the reflecting mirror 10 returns to the original state.
[0034]
Here, FIGS. 2 and 3 show a spectral reflection graph and chromaticity coordinates when the ion conductive coating 24 is formed of silicon dioxide and the conductive reflective film 16 is formed of aluminum.
[0035]
The chromaticity coordinates are described in JIS Z8701 “Color display method—XYZ color system and X ₁₀ Y ₁₀ Z ₁₀ color system”, and are basically well-known matters, and therefore detailed description thereof. Is omitted. The light source used for spectral reflection and chromaticity coordinates is “standard light C” (hereinafter referred to as “light source C” for convenience) as defined in JIS Z8720 “Standard Light and Standard Light Source for Colorimetry”. ").
[0036]
First, as shown in FIG. 2, in the visible region from 380 nm to 780 nm, the reflectance by the light source C in the non-colored state of the reduced-colored coating 22 is about 85.1%, whereas the reduced-colored coating 22 The reflectance of the light source C in the state where the light is colored is about 7.8%, and the difference in reflectance between the non-colored state and the colored state of the reduced colored coating 22 can be increased.
[0037]
Further, as shown in FIG. 3, the chromaticity coordinates for the light source C in the state in which the reduced coloring film 22 is colored are x = 0.2377 and y = 0.2214, and the whole is bluish white. On the other hand, the chromaticity coordinates for the light source C in the non-colored state of the reduced-colored coating film 22 are x = 0.3225 and y = 0.3346. White which does not transmit or absorb).
[0038]
4 and 5 show spectral reflection graphs and chromaticity coordinates when the ion conductive film 24 is formed of magnesium fluoride and the conductive reflective film 16 is formed of chromium. First, as shown in FIG. 4, in the visible region from 380 nm to 780 nm, the reflectance by the light source C in the non-colored state of the reduced colored film 22 is about 60.1%, whereas the reduced colored film 22. The reflectance by the light source C in the state where the is colored is about 6.7%, and the difference in reflectance between the non-colored state and the colored state of the reduced colored coating 22 can be increased.
[0039]
Further, as shown in FIG. 5, the chromaticity coordinates for the light source C in the state in which the reduced coloring film 22 is colored are x = 0.3833, y = 0.3538, and the overall bluish white On the other hand, the chromaticity coordinates with respect to the light source C in the non-colored state of the reduced-colored coating 22 are x = 0.3116 and y = 0.3236, which are neutral colors as a whole.
[0040]
Further, FIG. 6 and FIG. 7 show a spectral reflection graph and chromaticity coordinates when the ion conductive coating 24 is formed of magnesium fluoride and the conductive reflective film 16 is formed of rhodium. First, as shown in FIG. 6, in the visible region from 380 nm to 780 nm, the reflectance by the light source C in the non-colored state of the reduced colored coating 22 is about 77.5%, whereas the reduced colored coating 22 The reflectance by the light source C in the state where the color is colored is about 7.18%, and the difference in reflectance between the non-colored state and the colored state of the reduced colored coating 22 can be increased.
[0041]
Further, as shown in FIG. 7, the chromaticity coordinates for the light source C in the state in which the reduced coloring film 22 is colored are x = 0.3792 and y = 0.3600, which is a bluish white as a whole. On the other hand, the chromaticity coordinates with respect to the light source C in the non-colored state of the reduced-colored coating film 22 are x = 0.3230 and y = 0.3531, which are neutral colors as a whole.
[0042]
As described above, the reflecting mirror 10 has a structure in which the hydroxyl group generated by the above electrolysis reacts with the gold constituting the gold coating 26, so that the reduced colored coating 22 is colored and the coloring is released. The difference in transmittance of reflected light in the state can be increased. In addition, in the reflecting mirror 10, the conductive reflective film 16 is provided on the back surface side of the gold coating 26, and light is reflected by the conductive reflective film 16.
[0043]
That is, in the present reflecting mirror 10, the gold coating 26 basically has only a function of reacting with a hydroxyl group, and the function of reflecting light to the gold coating 26 is not required. Therefore, as described above, the thickness of the gold coating 26 can be reduced to such an extent that light can be sufficiently transmitted.
[0044]
As a result, the ratio of the reflected light reflected by the conductive reflective film 16 to the color of gold constituting the gold coating 26, that is, the golden color (yellowish color), can be sufficiently reduced. As a result, as described above, the color of the reflected light can be the neutral color as described above, and the reflected image formed by the reflected light can be a natural color.
[0045]
In the present embodiment, the reflective film and the electrode film are formed of a substantially single-layer film as the conductive reflective film 16, but the reflective film and the electrode film may be formed of substantially separate films. .
[0046]
【The invention's effect】
As described above, in the reflecting mirror according to the present invention, the difference in transmittance between when the reduced coloring film is colored and when it is not colored can be increased. Moreover, since the gold film only needs to have a function of reacting with a hydroxyl group generated by an electrochemical reaction, the gold film becomes thin, and the color of gold constituting the gold film can eliminate or reduce the influence of reflected light. . As a result, the color of the reflected light can be white or a color close to white.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view schematically showing a structure of a reflecting mirror according to an embodiment of the present invention.
FIG. 2 is a spectral reflection graph (a graph showing the relationship between the wavelength of reflected light and the reflectance) when an ion conductive film is formed of silicon dioxide and a conductive reflective film is formed of aluminum.
FIG. 3 is a chromaticity coordinate diagram when an ion conductive film is formed of silicon dioxide and a conductive reflective film is formed of aluminum.
FIG. 4 is a spectral reflection graph (a graph showing the relationship between the wavelength of reflected light and the reflectance) when an ion conductive film is formed of magnesium fluoride and a conductive reflective film is formed of chromium.
FIG. 5 is a chromaticity coordinate diagram when an ion conductive film is formed of magnesium fluoride and a conductive reflective film is formed of chromium.
FIG. 6 is a spectral reflection graph (a graph showing the relationship between the wavelength of reflected light and the reflectance) when an ion conductive film is formed of magnesium fluoride and a conductive reflective film is formed of rhodium.
FIG. 7 is a chromaticity coordinate diagram when an ion conductive film is formed of magnesium fluoride and a conductive reflective film is formed of rhodium.
[Explanation of symbols]
10 Reflector 12 Glass substrate (substrate)
16 Conductive reflective film (reflective film, electrode film)
20 Transparent electrode coating 22 Reduction coloring coating 24 Ion conductive coating 26 Gold coating

Claims (1)

A substrate that is substantially transparent or transmits light of a predetermined wavelength;
A substantially transparent transparent electrode film formed on the back side of the substrate, having conductivity and capable of transmitting light;
A reduction-colored film formed on the opposite side of the substrate through the transparent electrode film, and colored by a reversible electrochemical reaction upon application of a voltage;
An ion conductive film formed on the opposite side of the transparent electrode film through the reduced-colored film;
A reflective film having a gloss that is formed on the opposite side of the ion-conductive film from the reduced-colored film and capable of reflecting light incident from the substrate side;
Gold which is formed to have a thickness capable of transmitting light from the substrate side and the reflective film side, is provided on the ion conductive film side of the reflective film, and reacts with a hydroxyl group generated by the electrochemical reaction. A coating;
The reduced colored coating is colored by applying a voltage in the lamination direction of the reduced colored coating, the ion conductive coating, and the gold coating, or the coloring is released.
A reflector characterized by that.

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