Colored anti-fog mirror

Abstract

A colored anti-fogging mirror (11) comprising a structure including a reflective layer (14), a reflectance adjusting layer (20), a photocatalytic layer (16) and a hydrophilic layer (18) stacked sequentially on a surface of a base material (12), wherein the photocatalytic layer consists essentially of TiO 2 and the thickness of the photocatalytic layer is 140 to 200 nm, and the hydrophilic layer consists essentially of porous SiO 2 composed, whereby the maximum value of a remission in the visible light range occurs within a wavelength range of 430 to 560 nm, the mirror color is blue or green and the ratio between the maximum value and the minimum value of the remission in the visible light range is not less than 2 and not more than 4.

Description

Technical field

[0001] The present invention relates to a colored anti-fogging mirror using a surface mirror having a mirror color that is blue or green and anti-fogging properties, wherein the color deviation of the colored anti-fogging mirror occurring when the angle of a viewer's line of sight to the mirror surface changes is reduced, while the photocatalytic performance is improved compared with that of conventional products. State of the art

[0002] As exterior mirrors for vehicles, colored anti-fog mirrors are used in practice. These mirrors have a surface with a blue color and anti-fog properties. Fig. Figure 2 schematically shows a stacked structure of a colored antifogging mirror 10 conventionally used in practice. The colored antifogging mirror 10 is formed by sequentially stacking a reflective layer 14, a photocatalytic layer 16, and a hydrophilic layer 18 on a surface of a base material 12. The base material 12 is composed of a glass substrate such as soda glass. The reflective layer 14 is composed of a metal such as Cr. The photocatalytic layer 16 is made of TiO 2 The hydrophilic layer 18 is made of porous SiO 2The thickness of the photocatalytic layer 16 is set to about 75 nm so that the mirror color is blue. The colored anti-fogging mirror 10 produces a blue or green mirror color as a result of interference between reflected light from the respective layers. Further, anti-fogging properties are provided by the hydrophilic layer 18. Furthermore, organic dirt adhering to a surface of the hydrophilic layer 18 is decomposed and removed by the photocatalytic action of the photocatalytic layer 16, thereby maintaining the anti-fogging properties of the hydrophilic layer 18. A colored anti-fogging mirror having the above-mentioned structure is described in each of Patent Documents 1 and 2 indicated below. Document listPatent documents Patent document 1: JP 2001 - 141 916 A Patent document 2: JP 2007 - 286 491 A Summary of the inventionTechnical problem

[0003] Regarding the thickness of the photocatalytic TiO 2 layer, Patent Document 1 states that “with increasing thickness of TiO 2 -Film 10, the number of reflectance peaks in the visible light range increases. For this reason, although the light reflected from the mirror surface 14 has a peak within the wavelength range of 400 to 510 nm and maintains a blue color, the reflected light has a color in which other colors are superimposed on the blue color, and the color varies depending on the angle of a line of sight. Particularly, in the case of a mirror with a small radius of curvature, such as a hybrid curved mirror, such color variation causes color deviation. Therefore, to prevent such color deviation, it is preferable that the thickness of the TiO 2film 10 is adjusted to be not more than 150 nm, so that the reflectance has a single peak in the visible light range" (paragraph 0023 in the description).

[0004] Regarding the thickness of the photocatalytic TiO 2-layer, Patent Document 2 states that "there are no particular restrictions on the thickness of the photocatalytic film 16, as long as the thickness is adjusted so that the reflected light from the colored antifogging mirror 10 has a reflection spectrum that satisfies the conditions described above. However, the thickness is preferably within a range of 50 to 130 nm.When the thickness of the photocatalytic film 16 is below the above-mentioned lower limit, there is a tendency that no spectral reflection peak appears within the visible reflection range, whereas when the thickness is above the above-mentioned upper limit, there is a tendency that a plurality of spectral reflection peaks appear in the visible reflection range and, consequently, a color with other colors superimposed thereon appears, and the color tends to vary depending on the angle of a line of sight" (paragraph 0038 in the description).

[0005] As described above, in order to prevent color deviation that occurs when the angle at which an observer's line of sight is directed to a mirror surface changes (hereinafter referred to as "angle of line of sight": the angle of a line of sight is 0 degrees when the line of sight is directly directed to the mirror surface) in a colored anti-fogging mirror using a surface mirror having a mirror color that is blue and having anti-fogging properties, it has been conventionally recommended that the photocatalytic TiO 2 layer is formed to have a small thickness. However, it has been found that when the photocatalytic TiO 2-layer has a thickness of less than 140 nm, a problem arises regarding durability against a water-repellent vehicle wash, which has rapidly gained popularity in recent years. In other words, a water-repellent agent contained in a water-repellent vehicle wash used for a water-repellent vehicle wash contains a silicone resin as a main component, and when the water-repellent agent adheres to a surface of a mirror, the water-repellent agent cannot be removed by photocatalytic action. Therefore, along with repeated water-repellent vehicle washes, the water-repellent agent accumulates on the surface of the mirror, resulting in a reduction in photocatalytic performance. In this case, when the photocatalytic TiO 2-layer has a large thickness, a tolerance of the photocatalytic performance and consequently, even if the water-repellent agent has accumulated on the surface of the mirror to a certain extent, dirt adhering to the surface can be decomposed, thus restoring the hydrophilic properties. On the other hand, if the TiO 2 layer has a small thickness, no tolerance of the photocatalytic performance and consequently the accumulation of even a small amount of the water repellent on the surface of the mirror makes it impossible to decompose dirt adhering to the surface of the mirror, thus making it impossible to restore the hydrophilic properties.

[0006] The present invention has been made in view of the above points and is intended to provide a colored anti-fogging mirror using a surface mirror having a mirror color which is blue or green and anti-fogging properties, wherein a color deviation occurring with a change in the angle of a line of sight is reduced while durability against a water-repellent vehicle washing agent is increased. Solution to the problem

[0007] The present invention provides a colored antifogging mirror comprising a structure including a reflective layer, a reflectance adjusting layer, a photocatalytic layer and a hydrophilic layer stacked sequentially on a surface of a base material, wherein the photocatalytic layer consists essentially of TiO 2and the thickness of the photocatalytic layer is 140 to 200 nm, and the hydrophilic layer consists essentially of porous SiO 2 is composed, whereby the maximum value of a reflectance in the visible light range occurs within a wavelength range of 430 to 560 nm, the mirror color is blue or green and the ratio between the maximum value and the minimum value of the reflectance in the visible light range is not less than 2 and not more than 4. According to the present invention, the thickness of the photocatalytic TiO 2 -layer is made large, thereby increasing the photocatalytic performance and also increasing the durability against a water-repellent vehicle detergent. The large thickness of the photocatalytic TiO 2However, the reflectance adjustment layer causes a reduction in reflectance in the visible light region, and furthermore, the maximum and minimum reflectance values ​​occur in the visible light region, resulting in a significant color deviation that occurs when the angle of a line of sight changes. In this regard, in the present invention, the reflectance adjustment layer is disposed between the reflective layer and the photocatalytic layer, thereby reducing the reduction in reflectance in the visible light region, and furthermore, an increase in the ratio between the maximum and minimum reflectance values ​​in the visible light region is reduced, enabling a reduction in the color deviation that occurs when the angle of a line of sight changes.Furthermore, the ratio between the maximum value and the minimum value of the reflectance in the visible light region is not less than 2, whereby the mirror color can be adjusted to one color (blue or green), and the ratio is not more than 4, whereby the color deviation can be reduced. Although the present invention has the intended effect when the thickness of the photocatalytic layer is about 140 to 200 nm, no great increase in the photocatalytic effect occurs when the thickness of the photocatalytic layer reaches a certain thickness or more, and thus, it is practical that the thickness of the photocatalytic layer is about 165 ± 20 nm. Furthermore, the thickness of the photocatalytic layer can be adjusted to greater than 150 nm.

[0008] In the present invention, the reflectance adjusting layer may consist essentially of a mixture of Al 2 O 3and one or more of Ta 2 O 5 , SnO 2 and ZrO 2 In this case, if the reflectance adjustment layer consists essentially of a mixture of Al 2 O 3 and Ta 2 O 5 is composed, the volume percentage (hereinafter, % for a content percentage refers to a volume percentage) of Al 2 O 3 contained in the remission adjusting layer shall not be less than 50% and not more than 95% if the remission adjusting layer consists essentially of a mixture of Al 2 O 3 and SnO 2 the volume percentage may not be less than 30% and not more than 90%, and if the reflectance adjusting layer consists essentially of a mixture of Al 2 O 3 and ZrO 2the volume percentage may not be less than 40% and not more than 90%. According to the above, the reflectance adjusting layer contains any of Ta 2 O 5 , SnO 2 and ZrO 2 which reduces the decrease in water resistance properties caused by Al 2 O 3 In particular, if the reflectance adjustment layer consists essentially of a mixture of Al 2 O 3 and Ta 2 O 5 is composed of Al 2 O 3 contained in the reflectance adjustment layer is set to not less than 50% (or Ta 2 O 5 is set to no more than 50%), thereby providing a practically sufficient remission and providing an effect to reduce color deviation. Furthermore, Al 2 O 3contained in the reflectance adjustment layer is set to not more than 95% (or Ta 2 O 5 is adjusted to not less than 5%), which enables the provision of practically sufficient water resistance properties. If the reflectance adjustment layer consists essentially of a mixture of Al 2 O 3 and Ta 2 O 5 composed, Al 2 O 3 contained in the reflectance adjustment layer to not less than 70% (or Ta 2 O 5 can be set to no more than 30%) and no more than 95% (or Ta 2 O 5 can be set to not less than 5%). According to the above, Al 2 O 3contained in the reflectance adjusting layer is adjusted to not less than 70%, thereby enabling even more sufficient reflectance and providing a better color deviation reduction effect. Furthermore, when the reflectance adjusting layer consists essentially of a mixture of Al 2 O 3 and SnO 2 is composed of Al 2 O 3 contained in the reflectance adjusting layer is adjusted to not less than 30% (or SnO 2 is set to no more than 70%), thereby providing a practically sufficient remission and providing an effect to reduce color deviation. Furthermore, Al 2 O 3 contained in the reflectance adjustment layer is adjusted to not more than 90% (or SnO 2is adjusted to not less than 10%), which enables the provision of practically sufficient water resistance properties. Furthermore, when the reflectance adjusting layer consists essentially of a mixture of Al 2 O 3 and ZrO 2 is composed of Al 2 O 3 contained in the reflectance adjustment layer is adjusted to not less than 40% (or ZrO 2 is set to no more than 60%), thereby providing practically sufficient remission and providing an effect to reduce color deviation. Furthermore, Al 2 O 3 contained in the reflectance adjustment layer is adjusted to not more than 90% (or ZrO 2is set to not less than 10%), which enables the provision of practically sufficient water resistance properties. The thickness of the reflectance adjustment layer can be set, for example, to 35 to 85 nm. Short description of the drawings [ Fig. 1] Fig. 1 is a schematic cross-sectional diagram showing an embodiment of a colored anti-fogging mirror according to the present invention. [ Fig. 2] Fig. 2 is a schematic cross-sectional diagram showing a structure of a colored anti-fogging mirror conventionally used in practice. [ Fig. 3] Fig. Figure 3 is a graph showing the relationship between the thickness of the photocatalytic TiO 2 layer and the photocatalytic performance. [ Fig. 4] Fig. 4 is a table showing an example of film forming conditions for forming a reflectance adjusting layer 20, a photocatalytic layer 16 and a hydrophilic layer 18 of the colored antifogging mirror in the Fig. 1 by means of a vapor deposition process. [ Fig. 5] Fig. Figure 5 is a table showing main specifications of Examples 1 to 8 and Comparative Examples 1 to 4. [ Fig. 6] Fig. 6 is a graph showing a reflection spectrum in the visible light region of Example 1. [ Fig. 7] Fig. Figure 7 is a graph showing a visible light reflectance spectrum of Example 2. [ Fig. 8] Fig. Figure 8 is a graph showing a reflection spectrum in the visible light region of Example 3. [ Fig. 9] Fig. Figure 9 is a graph showing a visible light reflectance spectrum of Example 4. [ Fig. 10] Fig. 10 is a graph showing a reflection spectrum in the visible light region of Comparative Example 1. [ Fig. 11] Fig. 11 is a graph showing a reflection spectrum in the visible light region of Comparative Example 2. [ Fig. 12] Fig. 12 is a graph showing a reflection spectrum in the visible light region of Comparative Example 3. [ Fig. 13] Fig. 13 is a graph showing a reflection spectrum in the visible light region of Comparative Example 4. [ Fig. 14] Fig. Figure 14 is a table showing main properties of Examples 1 to 4 and Comparative Examples 1 to 4. [ Fig. 15A] Fig. 15A is a graph showing a reflection spectrum in the visible light region of Example 2 when the angle of a line of sight was changed. [ Fig. 15B] Fig. 15B is a table showing a maximum reflectance value, a minimum reflectance value, and a maximum / minimum reflectance ratio (which refers to maximum reflectance value / minimum reflectance value) in the visible light range according to the characteristics in the Fig. 15A. [ Fig. 16A] Fig. 16A is a graph showing a reflection spectrum in the visible light region of Example 3 when the angle of a line of sight was changed. [ Fig. 16B] Fig. 16B is a table showing a maximum reflectance value, a minimum reflectance value, and a maximum / minimum reflectance ratio in the visible light range according to the characteristics in the Fig. 16A. [ Fig. 17A] Fig. 17A is a graph showing a reflection spectrum in the visible light region of Example 4 when the angle of a line of sight was changed. [ Fig. 17B] Fig. 17B is a table showing a maximum reflectance value, a minimum reflectance value, and a maximum / minimum reflectance ratio in the visible light range according to the characteristics in the Fig. 17A indicates. [ Fig. 18A] Fig. 18A is a graph showing a reflection spectrum in the visible light region of Comparative Example 4 when the angle of a line of sight was changed. [ Fig. 18B] Fig. 18B is a table showing a maximum reflectance value, a minimum reflectance value, and a maximum / minimum reflectance ratio in the visible light range according to the characteristics in the Fig. 18A indicates. [ Fig. 19] Fig. Fig. 19 is a diagram showing a reflection spectrum in the visible light region of the conventional colored anti-fogging mirror 10 used in the Fig. 2 is shown. [ Fig. 20] Fig. Fig. 20 is a graph showing results of a comparison test between the colored anti-fogging mirrors 11 of Examples 1 to 4 and the conventional colored anti-fogging mirror 10 in the Fig. 2 with regard to the durability of the photocatalytic performance against a water-repellent vehicle detergent. [ Fig. 21] Fig. Figure 21 is a graph showing a visible light reflectance spectrum of Example 5. [ Fig. 22] Fig. Figure 22 is a graph showing a visible light reflectance spectrum of Example 6. [ Fig. 23] Fig. Figure 23 is a graph showing a visible light reflectance spectrum of Example 7. [ Fig. 24] Fig. Figure 24 is a graph showing a visible light reflectance spectrum of Example 8. Description of an embodiment

[0009] An embodiment of the present invention will be described below. Fig. 1 schematically shows a stacked structure of a colored anti-fogging mirror 11 according to the present invention. The colored anti-fogging mirror 11 constitutes a mirror body part of an exterior mirror for a vehicle. The colored anti-fogging mirror 11 is formed by sequentially stacking a reflective layer 14, a reflectance adjusting layer 20, a photocatalytic layer 16, and a hydrophilic layer 18 on a surface of a base material 12. The colored anti-fogging mirror 11 produces a mirror color that is blue or green by interference between reflected light from the respective layers. Each of the layers will be described. <Basismaterial 12>

[0010] The base material 12 is composed of a glass substrate, such as soda glass. <Reflektierende Schicht 14>

[0011] The reflective layer 14 is composed of a metal such as Cr. <Photokatalytische Schicht 16>

[0012] The photocatalytic layer 16 is made of TiO 2 In the colored anti-fogging mirror 10 in the Fig. 2, which is conventionally used in practice, the thickness of the photocatalytic TiO 2 -layer 16 to obtain a mirror color which is blue, adjusted to about 75 nm. In the colored anti-fogging mirror 11 in the Fig. 1, the thickness of the photocatalytic layer 16 is set to a large thickness of 140 to 200 nm to obtain a mirror color that is blue (or a green color). The photocatalytic layer 16 decomposes and removes organic dirt adhering to a surface of the hydrophilic layer 18 by means of a photocatalytic action, thereby maintaining the anti-fogging properties of the hydrophilic layer 18. <Hydrophile Schicht 18>

[0013] The hydrophilic layer 18 is made of porous SiO 2 The thickness of the hydrophilic layer 18 is set to 15 nm, for example. The hydrophilic layer 18 provides anti-fogging properties. <Remissionseinstellschicht 20>

[0014] The reflectance adjusting layer 20 is composed of a material having a refractive index lower than that of the photocatalytic layer 16, such as a mixture of, for example, Al 2 O 3 and Ta 2 O 5 , a mixture of Al 2 O 3 and SnO 2 or a mixture of Al 2 O 3 and ZrO 2 The reflectance adjustment layer 20 reduces a decrease in reflectance resulting from adjusting the thickness of the photocatalytic layer 16 to a large value (140 to 200 nm) and reduces the color deviation that occurs when the angle of a line of sight changes. The function of reducing the decrease in reflectance and the color deviation is mainly performed by Al 2 O 3 However, if the reflectance adjustment layer 20 consists only of Al 2 O 3composed, the water resistance properties are insufficient and consequently the water resistance properties are improved by mixing e.g. Ta 2 O 5 , SnO 2 or ZrO 2 improved. If the reflectance adjusting layer 20 is a mixture of Al 2 O 3 and Ta 2 O 5 is the volume percentage of Al 2 O 3 contained in the reflectance adjusting layer 20 is set to not less than 50% and not more than 95% (preferably not less than 70% and not more than 95%). In this case, the volume percentage of Ta 2 O 5 contained in the reflectance adjusting layer 20 is set to not more than 50% and not less than 5% (preferably not more than 30% and not less than 5%). Furthermore, when the reflectance adjusting layer 20 is a mixture of Al 2 O 3 and SnO 2is the volume percentage of Al 2 O 3 contained in the reflectance adjusting layer 20 is set to not less than 30% and not more than 90%. In this case, the volume percentage of SnO 2 contained in the reflectance adjusting layer 20 is set to not more than 70% and not less than 10%. Furthermore, when the reflectance adjusting layer 20 is a mixture of Al 2 O 3 and ZrO 2 is the volume percentage of Al 2 O 3 contained in the reflectance adjusting layer 20 is set to not less than 40% and not more than 90%. In this case, the volume percentage of ZrO 2contained in the reflectance adjusting layer 20 is adjusted to not more than 60% and not less than 10%. In the colored anti-fogging mirror 11, the maximum / minimum reflectance ratio is smaller as the thickness of the reflectance adjusting layer 20 is greater. However, when the reflectance adjusting layer 20 has a large thickness, in order to obtain a mirror color similar to that of a case where the thickness is small, it is necessary to make the photocatalytic layer 16 thin compared to the case where the thickness is small, resulting in a reduction in the photocatalytic performance. Here, the relationship between the thickness of the photocatalytic layer 16 and the photocatalytic performance is as shown in Fig. 3. In other words, when the thickness is small, the photocatalytic performance increases along with the increase in thickness; however, when the thickness reaches a certain value or more, the photocatalytic performance becomes saturated. Therefore, the thickness of the photocatalytic layer 16 is set to the minimum thickness (140 to 200 nm) that enables the provision of photocatalytic performance at approximately the saturation value, and under these conditions, the thickness of the reflectance adjusting layer 20 is adjusted so that the desired specular color (here, blue or green) is obtained and the maximum / minimum reflectance ratio is not less than 2 and not more than 4.When the thickness of the reflectance adjusting layer 20 is set to 35 to 85 nm, the properties satisfying the required conditions (reflectance required for an automobile mirror, photocatalytic performance around the saturation value, mirror color being a blue or green color, and maximum / minimum reflectance ratio of not less than 2 and not more than 4) are obtained.

[0015] The colored antifogging mirror 11 can be manufactured by sequentially forming the reflective layer 14, the reflectance adjusting layer 20, the photocatalytic layer 16, and the hydrophilic layer 18 on a surface of the base material by a PVD method such as a vapor deposition method or a sputtering method or other thin film forming method. An example of film forming conditions for forming the reflectance adjusting layer 20, the photocatalytic layer 16, and the hydrophilic layer 18 by a vapor deposition method is shown in Fig. 4 is specified. Examples

[0016] Examples and comparative examples of the present invention will be described. For the colored anti-fogging mirror 11 having the Fig. 1, Examples 1 to 8 and Comparative Examples 1 to 4 were prepared, which have the Fig. 5, wherein the thickness of the photocatalytic layer 16 and the composition of the reflectance adjusting layer 20 are different (in Comparative Example 4, no reflectance adjusting layer 20 was provided), and various properties were measured. Furthermore, in each of Examples 1 to 8 and Comparative Examples 1 to 4, the thickness of the hydrophilic layer 18 was set to 15 nm. Fig. 6 to 13 show respective reflection spectra in the visible light range of Examples 1 to 4 and Comparative Examples 1 to 4. The Fig. Figure 14 shows the main characteristics of Examples 1 to 4 and Comparative Examples 1 to 4 (integrating sphere reflectance, maximum reflectance value and minimum reflectance value in the visible light range, maximum / minimum reflectance ratio, and degree of color variation occurring with a change in the angle of a line of sight, water resistance performance, and acid resistance performance). "Integrating sphere reflectance" is a reflectance measured by an indirect measurement method using an integrating sphere according to JIS D 5705. "Water resistance performance" is determined by determining whether the films peeled off after immersing each sample in tap water and boiling the water for two hours.The "acid resistance performance" is determined by determining whether the films peeled off after dropping sulfuric acid with a concentration of 0.1 N onto one surface of each sample and allowing the sample to stand for 24 hours. For both the "water resistance performance" and the "acid resistance performance," "good" means that there was no peeling film or that no discoloration occurred, and "poor" means that there was a peeling film or that discoloration occurred. The . Fig. 6 to 14 show the following. (a) In Examples 1 to 4 and Comparative Examples 1 to 4, the respective wavelengths at which a maximum value of reflectance occurs are substantially identical and the respective mirror colors are all blue. (b) The integrating sphere reflectance of Comparative Example 4 is a value close to 35%, which is the lower limit of the reflectance of an automotive mirror according to JIS D 5705 (an integrating sphere reflectance of not less than 40% is suitable for an automotive mirror), and thus is insufficient. The low reflectance of Comparative Example 4 is a result of forming the photocatalytic layer 16 to have a large thickness. In contrast, Examples 1 to 4 each have a reflectance sufficiently high for an automotive mirror. The high reflectance of each of Examples 1 to 4 is a result of mitigating the decrease in reflectance by Al. 2 O 3 , which is included in the reflectance adjusting layer 20, due to the formation of the photocatalytic layer 16 such that it has a large thickness. (c) In Comparative Examples 2 and 3, whose maximum / minimum reflectance ratio is large (i.e., the ratio between a reflectance value of a color-generating strong reflection and a reflectance value of a color-generating weak reflection is large), the color deviation occurring with a change in the angle of a line of sight is large. In contrast, in Examples 1 to 4, whose maximum / minimum reflectance ratio is small, the color deviation occurring with a change in the angle of a line of sight is small. A maximum / minimum reflectance ratio of not more than 4 enables the color deviation to be reduced to a degree that does not cause a problem for practical use. (d) When Examples 1 to 4 are compared with each other, the integrating sphere reflectance of each of Examples 2 to 4 is higher than that of Example 1, and the maximum / minimum reflectance ratio of each of Examples 2 to 4 is smaller than that of Example 1. Therefore, each of Examples 2 to 4 enables the provision of a reflectance higher than that of Example 1 and enables a greater reduction in color deviation than that of Example 1. (e) Comparative Example 1 exhibits insufficient water resistance performance. In contrast, each of Examples 1 to 4 exhibits sufficient water resistance performance and acid resistance performance.

[0017] The relationship between the maximum / minimum remission ratio and the color deviation that occurs when the angle of a line of sight is changed is described. Fig. Figure 15A shows visible light reflectance spectra of Example 2 when the line of sight angle is 0 degrees (viewed directly from the front of the mirror surface), 30 degrees, and 45 degrees. Fig. Figure 15B shows the maximum reflectance values ​​and the minimum reflectance values ​​in the visible light range and the maximum / minimum reflectance ratios according to the properties in the Fig. 15A.

[0018] Accordingly, the Fig. 16A Reflectance spectra in the visible light range of Example 3 when the line of sight angle is 0 degrees, 30 degrees, and 45 degrees. The Fig. Figure 16B shows the maximum reflectance values ​​and the minimum reflectance values ​​in the visible light range and the maximum / minimum reflectance ratios according to the properties in the Fig. 16A.

[0019] Accordingly, the Fig. 17A Reflectance spectra in the visible light range of Example 4 when the line of sight angle is 0 degrees, 30 degrees, and 45 degrees. The Fig. Figure 17B shows the maximum reflectance values ​​and the minimum reflectance values ​​in the visible light range and the maximum / minimum reflectance ratios according to the properties in the Fig. 17A.

[0020] Accordingly, the Fig. 18A Reflectance spectra in the visible light range of Comparative Example 4 when the line of sight angle is 0 degrees, 30 degrees, and 45 degrees. Fig. Figure 18B shows the maximum reflectance values ​​and the minimum reflectance values ​​in the visible light range and the maximum / minimum reflectance ratios according to the properties in the Fig. 18A.

[0021] According to the Fig. 18B, in Comparative Example 4, whose maximum / minimum reflectance ratio is large, the color varies greatly when the angle of a line of sight is changed from 0 degrees, since the fluctuation of the maximum / minimum reflectance ratio according to the change of the angle of a line of sight is large, and consequently, the mirror color varies to a reddish color or becomes brighter from blue, which is the color when the angle of a line of sight is 0 degrees. Further, according to the Fig. 15B, Fig. 16B and Fig. 17B, ​​in each of Examples 2, 3, and 4, whose maximum / minimum reflectance ratio is small, a variation in the color of the mirror color can be reduced (ie, the color deviation can be reduced) compared to Comparative Example 4 even when the angle of a line of sight changes from 0 degrees, since the fluctuation of the maximum / minimum reflectance ratio according to the change in the angle of the line of sight is small. Fig. 19 shows a reflection spectrum in the visible light range of the conventional colored anti-fogging mirror 10 in the Fig. 2 (the thickness of the photocatalytic layer 16 is 75 nm). When the thickness of the photocatalytic layer 16 is 75 nm, there is a single maximum value and no minimum value in the visible light range. Consequently, the variation in reflectance according to wavelength is small, and the problem of color deviation that occurs when the angle of a line of sight changes does not occur. In other words, the problem of color deviation that occurs when the angle of a line of sight changes occurs when the thickness of the photocatalytic layer 16 is large, causing a large variation in reflectance.

[0022] Differences in photocatalytic performance between the colored anti-fogging mirror 11 according to the present invention in the Fig. 1 and the conventional colored anti-fogging mirror 10 in the Fig. 2. The Fig. 20 shows test results when a test in which a vehicle on which the relevant mirror was mounted was subjected to water-repellent vehicle washing and then the mirror was removed and subjected to ultraviolet irradiation and the water drop contact angle on a mirror surface was measured, for each of the colored anti-fogging mirrors 11 according to Examples 1 to 4 and the conventional colored anti-fogging mirror 10 (the thickness of the photocatalytic layer 16 is 70 nm) in the Fig. 2 was carried out repeatedly. According to the Fig. 20, in the colored antifogging mirrors 11 according to Examples 1 to 4, the number of repetitions until the water droplet contact angle greatly increases is not less than two, which is almost three times as much as that of the conventional colored antifogging mirror 10, and thus it can be seen that the photocatalytic performance was dramatically increased as compared with that of the conventional colored antifogging mirror 10.

[0023] Example 5 of the colored anti-fogging mirror 11 according to the present invention in the Fig. 1 is described. The mirror color of the colored anti-fogging mirror 11 is green. The structure of each layer in Example 5 is as follows. <Reflektierende Schicht 14> Composition: Cr. <Remissionseinstellschicht 20> Composition: Mixture of Al 2 O 3 (70% by volume) and Ta 2 O5 (30 volume%), thickness: 70 nm. <Photokatalytische Schicht 16> Composition: TiO 2 , Thickness: 165 nm. <Hydrophile Schicht 18> Composition: porous SiO 2 , Thickness: 15 nm.

[0024] The Fig. 21 shows a reflection spectrum in the visible light region of Example 5. According to the figure, the following characteristics are obtained. - Integrating ball remission: 62% - Maximum reflectance: 78.3% (at 532 nm) - Minimum reflectance value: 25.1% (at 707 nm) - Maximum / minimal remission ratio: 3.1 - Mirror color: green

[0025] Example 6 of the colored anti-fogging mirror 11 according to the present invention in the Fig. 1 is described. The mirror color of this example is also green. The structure of each layer in Example 6 is as follows. <Reflektierende Schicht 14>Composition: Cr. <Remissionseinstellschicht 20> Composition: Mixture of Al 2 O 3 (70% by volume) and Ta 2 O 5 (30 volume%), thickness: 35 nm. <Photokatalytische Schicht 16> Composition: TiO 2 , Thickness: 200 nm. <Hydrophile Schicht 18> Composition: porous SiO 2 , Thickness: 15 nm.

[0026] The Fig. Figure 22 shows a visible light reflectance spectrum of Example 6. The figure shows that the following properties are obtained. - Integrating ball remission: 63% - Maximum reflectance value: 75.2% (at 556 nm) - Minimum reflectance value: 18.8% (at 734 nm) - Maximum / minimal remission ratio: 4.0 - Mirror color: green

[0027] Example 7 of the colored anti-fogging mirror 11 according to the present invention in the Fig. 1 is described. The mirror color of this example is also green. The structure of each layer in Example 7 is as follows. <Reflektierende Schicht 14> Composition: Cr. <Remissionseinstellschicht 20> Composition: Mixture of Al 2 O 3 (50% by volume) and SnO 2 (50 volume%), thickness: 67 nm. <Photokatalytische Schicht 16> Composition: TiO 2 , Thickness: 165 nm. <Hydrophile Schicht 18> Composition: porous SiO 2 , Thickness: 15 nm.

[0028] The Fig. Figure 23 shows a visible light reflectance spectrum of Example 7. The figure shows that the following properties are obtained. - Integrating ball remission: 64% - Maximum reflectance value: 78.4% (at 530 nm) - Minimum reflectance value: 24.1% (at 715 nm) - Maximum / minimal remission ratio: 3.2 - Mirror color: green

[0029] Example 8 of the colored anti-fogging mirror 11 according to the present invention in the Fig. 1 is described. The mirror color of this example is also green. The structure of each layer in Example 8 is as follows. <Reflektierende Schicht 14> Composition: Cr. <Remissionseinstellschicht 20> Composition: Mixture of Al 2 O 3 (60% by volume) and ZrO 2 (40 volume%), thickness: 60 nm. <Photokatalytische Schicht 16> Composition: TiO 2 , Thickness: 170 nm. <Hydrophile Schicht 18> Composition: porous SiO 2 , Thickness: 15 nm.

[0030] The Fig.Figure 24 shows a visible light reflectance spectrum of Example 8. The figure shows that the following properties are obtained. - Integrating ball remission: 65% - Maximum reflectance value: 78.8% (at 530 nm) - Minimum reflectance value: 23.4% (at 716 nm) - Maximum / minimal remission ratio: 3.4 - Mirror color: green List of reference symbols

[0031] 11 ... Colored anti-fogging mirror, 12 ... Substrate (base material), 14 ... Reflective layer, 16 ... Photocatalytic layer, 18 ... Hydrophilic layer, 20 ... Reflectance adjustment layer

Claims

[1] A colored anti-fogging mirror (11) comprising a structure including a reflective layer (14), a reflectance adjusting layer (20), a photocatalytic layer (16) and a hydrophilic layer (18) stacked sequentially on a surface of a base material (12), wherein the photocatalytic layer is composed essentially of TiO2 and the thickness of the photocatalytic layer is 140 to 200 nm, and the hydrophilic layer is essentially composed of porous SiO2, whereby the maximum value of remission in the visible light range occurs within a wavelength range of 430 to 560 nm, the mirror colour is blue or green and the ratio between the maximum value and the minimum value of remission in the visible light range is not less than 2 and not more than 4. [2] A colored antifogging mirror according to claim 1, wherein the reflectance adjusting layer is composed essentially of a mixture of Al2O3 and Ta2O5, and the volume percentage of Al2O3 contained in the reflectance adjusting layer is not less than 50% and not more than 95%. [3] A colored antifogging mirror according to claim 1, wherein the reflectance adjusting layer is composed essentially of a mixture of Al2O3 and SnO2, and the volume percentage of Al2O3 contained in the reflectance adjusting layer is not less than 30% and not more than 90%. [4] A colored antifogging mirror according to claim 1, wherein the reflectance adjusting layer is composed essentially of a mixture of Al2O3 and ZrO2, and the volume percentage of Al2O3 contained in the reflectance adjusting layer is not less than 40% and not more than 90%. [5] A colored antifogging mirror according to claim 1, wherein the thickness of the reflectance adjusting layer is 35 to 85 nm. [6] A colored antifogging mirror according to claim 2, wherein the thickness of the reflectance adjusting layer is 35 to 85 nm. [7] A colored antifogging mirror according to claim 3, wherein the thickness of the reflectance adjusting layer is 35 to 85 nm. [8] A colored antifogging mirror according to claim 4, wherein the thickness of the reflectance adjusting layer is 35 to 85 nm. [9] A colored antifogging mirror according to claim 1, wherein the thickness of the photocatalytic layer is 165 ± 20 nm. [10] A colored anti-fogging mirror according to claim 2, wherein the thickness of the photocatalytic layer is 165 ± 20 nm. [11] A colored anti-fogging mirror according to claim 3, wherein the thickness of the photocatalytic layer is 165 ± 20 nm. [12] A colored anti-fogging mirror according to claim 4, wherein the thickness of the photocatalytic layer is 165 ± 20 nm. [13] A colored anti-fogging mirror according to claim 1, wherein the thickness of the photocatalytic layer is greater than 150 nm. [14] A colored anti-fogging mirror according to claim 2, wherein the thickness of the photocatalytic layer is greater than 150 nm. [15] A colored anti-fogging mirror according to claim 3, wherein the thickness of the photocatalytic layer is greater than 150 nm. [16] A colored anti-fogging mirror according to claim 4, wherein the thickness of the photocatalytic layer is greater than 150 nm.

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