JP2017206392A - Glass article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high transmissible glass article having an anti-reflection film formed on a glass substrate having a specific wavelength range low in transmittance in a visible light wavelength region and having enhanced transmittance of the glass substrate over all visible light wavelength region almost uniformly.SOLUTION: There is provided a glass article having a glass substrate and an anti-reflection film arranged on at least one surface of the glass substrate, the glass substrate has a distribution with a first wavelength range so that transmittance of a light in a visible light wavelength region of 400 to 700 nm injected from the surface has average transmittance lower than average transmittance of whole visible light wavelength range in the visible light wavelength region and average reflection rate of the light in the first wavelength range regarding reflection rate of the light injected from the surface of the anti-reflection film in the glass article is lower than the average reflection of the light of whole visible light wavelength region and is 0.5% or less.SELECTED DRAWING: Figure 3A

Description

  The present invention relates to a glass article, and more particularly, to a glass article having a uniform and high transmittance in the entire visible light wavelength region.

  It is known that an optical product having an antireflection film on a surface such as a lens or a prism is used in an optical instrument to improve the transmittance of the entire optical instrument (see, for example, Patent Document 1).

  On the other hand, when glass is used for optical equipment for projectors and cameras, it is important to display the color of the image uniformly. Therefore, it is preferable to make uniform the transmittance | permeability in each wavelength range of R area | region (wavelength 600-640 nm), G area | region (wavelength 530-570 nm), and B area | region (wavelength 410-500 nm) of the light which permeate | transmits glass. Here, the glass is usually mixed with an impurity component such as iron, rhodium, platinum or the like that lowers the transmittance in a specific wavelength region. By reducing the content of such impurity components to a certain extent, a glass having a substantially uniform transmittance in the visible light wavelength region can be obtained.

  Recently, an attempt has been made to improve the transmittance by forming an antireflection film as described in Patent Document 1 on such glass. However, in the state where the antireflection film is not provided, even when the glass has a substantially uniform transmittance as described above, the antireflection film is formed to increase the transmittance as a whole, but the light absorption of the impurity component is increased. There is a problem in that the amount of light absorption increases in the region, thereby causing the transmittance to be nonuniform in the visible light wavelength region.

JP 2002-267803 A

  By further suppressing the mixing of impurity components contained in the glass, the transmittance in the entire visible light wavelength region can be made uniform. In this case, it is necessary to strictly suppress the mixing of impurities from the glass raw material and the process. There is a problem in that the manufacturing cost is high. In addition, using an antireflection film that adjusts the reflectivity of the region in accordance with the specific absorption wavelength region of the glass, the attempt to uniformly increase the transmittance of the obtained glass with an antireflection film over the entire visible light wavelength region is It has never been done so far.

  The present invention relates to a glass article in which an antireflection film is formed on a glass substrate having a specific wavelength range having low transmittance in the visible light wavelength range, and the transmittance of the glass substrate is substantially uniform over the entire visible wavelength range. It aims at providing the glass article of the high transmittance | permeability raised so that it might become.

  The glass article of the present invention is a glass article having a glass substrate and an antireflection film provided on at least one surface of the glass substrate, the glass substrate having a wavelength of 400 to 700 nm incident from the surface. The glass has a distribution such that the transmittance of light in the visible light wavelength region has a first wavelength region having an average transmittance lower than the average transmittance of the entire visible light wavelength region in the visible light wavelength region, and the glass. Regarding the reflectance of light incident from the surface of the antireflection film in the article, the average reflectance of light in the first wavelength range is lower than the average reflectance of light in the entire visible wavelength range and 0.5% It is characterized by the following.

  In the glass article of the present invention, the first wavelength region is a wavelength region of 400 to 500 nm, and the average transmittance of light in the first wavelength region incident on the surface of the glass substrate is 85 to 92. % Is preferred.

  In the glass article of the present invention, the antireflection film is preferably an optical multilayer film. The number of layers of the optical multilayer film is preferably 8 or less.

In the glass article of the present invention, it is preferable that the antireflection film is an optical multilayer film including alternating laminated portions of SiO ₂ layers and Nb ₂ O ₅ layers. The antireflection film preferably has a thickness of 200 to 450 nm.

  In the glass article of the present invention, in the transmittance of light in the visible light wavelength range incident on the glass article so as to pass through the antireflection film, the average transmittance is 93% or more, the maximum value and the minimum value. The difference is preferably 2% or less.

  According to the present invention, in a glass article in which an antireflection film is formed on a glass base material having a specific wavelength range with low transmittance in the visible light wavelength range, the transmittance of the glass base material covers the entire visible light wavelength range. It is possible to provide a glass article having a high transmittance that is increased to be substantially uniform.

It is sectional drawing of an example of embodiment of the glass article of this invention. It is a graph which shows the transmittance | permeability of the glass article of Example 1 (Example) in an Example. It is a graph which shows the reflectance of the light which injects from the antireflection film side of the glass article of Example 1 (Example) in an Example. It is a graph which shows the transmittance | permeability of the glass article of Example 2 (Example) in an Example. It is a graph which shows the reflectance of the light which injects from the antireflection film side of the glass article of Example 2 (Example) in an Example. It is a graph which shows the transmittance | permeability of the glass article of Example 3 (comparative example) in an Example. It is a graph which shows the reflectance of the light which injects from the antireflection film side of the glass article of Example 3 (comparative example) in an Example. It is a graph which shows the transmittance | permeability of the glass article of Example 4 (comparative example) in an Example. It is a graph which shows the reflectance of the light which injects from the antireflection film side of the glass article of Example 4 (comparative example) in an Example. It is a graph which shows the transmittance | permeability of the glass base material of Example 5 (reference example) in an Example. It is a graph which shows the reflectance of the glass base material of Example 5 (reference example) in an Example.

  Embodiments of the present invention will be described below with reference to the drawings. Note that the present invention is not limited to these embodiments, and these embodiments can be changed or modified without departing from the spirit and scope of the present invention.

  FIG. 1 is a cross-sectional view of an example of an embodiment of a glass article of the present invention. Glass article 3 has glass substrate 1 and antireflection film 2 provided on one main surface 1a side of glass substrate 1.

  The glass substrate 1 used for the glass article 3 has an average transmission of light in the visible light wavelength region of 400 to 700 nm incident from the main surface 1a, which is lower than the average transmittance of the entire visible light wavelength region within the visible light wavelength region. The distribution has a first wavelength region having a rate. In the present specification, unless otherwise specified, the “visible light wavelength region” means a wavelength region of 400 to 700 nm.

  In the glass article 3, the average reflectance of light in the first wavelength range is lower than the average reflectance of light in the entire visible wavelength range with respect to the reflectance of light incident from the surface 2 a of the antireflection film 2. And 0.5% or less.

  In this specification, the transmittance | permeability of the specific wavelength in a glass base material and a glass article, for example, the visible light wavelength range of 400-700 nm, can be measured with a common spectrophotometer, for example, U4100 by Hitachi. Moreover, the specific wavelength in the predetermined | prescribed surface of a glass article and a glass base material, for example, the reflectance of the visible light wavelength range of 400-700 nm, can be measured with a normal spectrophotometer. As a spectrophotometer, Otsuka Electronics FE3000, Hitachi U4100, etc. are mentioned, for example.

(Glass substrate)
In this embodiment, the glass base material 1 has two main surfaces 1a and 1b facing each other, and the antireflection film 2 is formed on the main surface 1a side. In the glass substrate 1, the transmittance measured on the main surface 1 b side of light in the visible light wavelength region of 400 to 700 nm incident from the main surface 1 a is less than the average transmittance of the entire visible light wavelength region within the visible light wavelength region. The distribution has a first wavelength region having a low average transmittance.

  The first wavelength region is a wavelength region that is within the visible light wavelength region and narrower than the visible light wavelength region, and has a width (short wavelength side wavelength) as long as it has an average transmittance that satisfies the above conditions. And the position in the visible light wavelength range, such as the short wavelength side and the long wavelength side, are not particularly limited.

  The first wavelength region may be on the short wavelength side of the visible light wavelength region, in the intermediate region, or on the long wavelength side. The first wavelength region may be, for example, a B region (wavelength 410 to 500 nm), a G region (wavelength 530 to 570 nm), and an R region (wavelength 600 to 640 nm) as wavelengths corresponding to colors. Furthermore, the first wavelength region may be a wavelength region corresponding to a color other than these.

  The width of the first wavelength region is preferably about 100 nm. The first wavelength region is preferably 400 to 500 nm from the viewpoint that the effects in the present invention are remarkably obtained. In this case, the first wavelength region substantially corresponds to the B region (wavelength 410 to 500 nm). For example, if the average transmittance of the B region is lower than the average transmittance of the entire visible light wavelength range, that is, if the average transmittance of the B region is lower than the average transmittance of the region other than the B region in the visible light wavelength range, The color in the blue region does not appear clearly compared to other colors.

  In the glass substrate 1, the average transmittance in the first wavelength region is preferably 85 to 92%, and more preferably 87 to 92%. The average transmittance of the entire visible light wavelength region in the glass substrate 1 is not particularly limited as long as it is higher than the average transmittance of the first wavelength region. Even in the case of a glass substrate having a first wavelength region in the visible light wavelength region, the difference between the average transmittance in the visible light wavelength region and the average transmittance in the first wavelength region usually falls within a certain range. Is set to From such a viewpoint, when the average transmittance of the entire visible light wavelength region in the glass substrate is Tag and the average transmittance in the first wavelength region is Tbg, the difference Tdg between the two expressed by Tag−Tbg is: 0.1 to 1.0% is preferable, and 0.1 to 0.8% is more preferable.

  The shape of the glass substrate 1 is not particularly limited, and may be a block shape, a plate shape, or a film shape. Moreover, what was shape | molded by arbitrary shapes with the metal mold | die etc. may be used. When the glass substrate 1 is plate-shaped or film-shaped, the thickness of the glass substrate 1 is appropriately adjusted according to the application of the glass article 3.

  The glass substrate constituting the glass substrate 1 has a glass substrate having a first wavelength region having an average transmittance lower than the average transmittance of the entire visible light wavelength region in the light transmittance distribution in the visible light wavelength region. If it is a composition which can be obtained, it will not be restrict | limited. Examples of the glass constituting the glass substrate 1 include soda lime glass, borosilicate glass, alkali-free glass, aluminosilicate glass, alkali-free aluminosilicate glass, and the like.

(Antireflection film)
The antireflection film 2 is formed on one main surface 1a of the glass substrate 1 and has an antireflection function, whereby the glass article 1 has a light transmittance in the visible light wavelength region of the glass article 3 to be obtained. Compared with the light transmittance in the visible light wavelength region, it has a function of uniformly increasing the entire region. More specifically, the antireflection film 2 has an average reflectance of light in the first wavelength range, in the visible light wavelength range, for the reflectance of light incident from the surface 2a of the antireflection film 2 in the glass article 3. It has a function of being lower than the average reflectance of the whole light and not more than 0.5%.

  In the present specification, unless otherwise specified, the reflectance refers to the reflectance of light incident from the surface 2 a of the antireflection film 2 for the glass article 3. Further, the reflectance of the glass substrate 1 refers to the reflectance of light incident from the main surface 1 a of the glass substrate 1. About the transmittance | permeability in the glass article 3, it is the transmittance | permeability measured by the main surface 1b side of the glass base material 1 of the light which injects from the surface 2a of the reflection preventing film 2. FIG. The transmittance of the glass substrate 1 is a transmittance measured on the main surface 1b side of the glass substrate 1 of light incident from the main surface 1a of the glass substrate 1.

  In the glass article 3, if the average reflectance of light in the first wavelength region is not lower than the average reflectance of light in the entire visible light wavelength region, the light transmittance in the first wavelength region and the first reflectance in the visible light wavelength region. The difference between the transmittances in the wavelength regions other than the wavelength region of 1 is larger than the difference between the two in the glass substrate 1. Further, if the average reflectance of light in the first wavelength range is more than 0.5%, the average transmittance of light in the first wavelength range is not sufficiently improved in the glass article 3, and the visible wavelength range It is difficult to make it equal to the average transmittance in a wavelength region other than the first wavelength region.

  In the glass article 3, the average reflectance of light in the first wavelength region is preferably 0.45% or less, preferably 0.4% or less, and most preferably 0.35% or less.

  In the glass article 3, when the average reflectance of light in the entire visible light wavelength region is Ra and the average reflectance of light in the first wavelength region is Rb, Ra> Rb as described above. In the glass article 3, when Rd is a value obtained by subtracting Rb from Ra, Rd is preferably 0.01 or more, and more preferably 0.05 or more.

  Further, regarding the transmittance in the glass article 3, when the average transmittance measured on the main surface 1b side of the glass substrate 1 of the light in the visible light wavelength range incident from the surface 2a of the antireflection film 2 is Ta, Although it depends on the glass substrate 1 to be used, the Ta value is preferably 93% or more, more preferably 94% or more. The difference (Ta-Tag) between the average transmittance Tag of the visible light wavelength region of the glass substrate 1 to be used and the average transmittance Ta of the visible light wavelength region of the glass article 3 to be obtained is 2.5. % Or more is preferable, and 3.0% or more is more preferable.

  When the average transmittance of light in the first wavelength range in the glass article 3 measured in the same manner as the transmittance of light in the visible wavelength range is Tb, the average transmittance Ta of the light in the visible wavelength range and the first The relationship with the average transmittance Tb of the light in the wavelength range of Ta may be Ta> Tb, Ta = Tb, Ta <Tb, but the absolute value | Td | of the difference between them (Ta−Tb = Td) is 1.0% or less is preferable, and 0.8% or less is more preferable.

  From another viewpoint, the absolute value | Td | of the difference between Ta and Tb is the average transmittance Tag of light in the visible wavelength range and the average transmittance of light in the first wavelength range in the glass substrate 1 to be used. It is preferable that the difference from Tbg is the same as Tdg or smaller than Tdg.

  Furthermore, the difference between the maximum value and the minimum value of the light transmittance in the visible light wavelength region of the glass article 3 is preferably 2% or less, and more preferably 1.5% or less. If the difference between the maximum value and the minimum value of the light transmittance in the visible light wavelength range is 2% or less, the transmittance difference in each of the R, G, and B regions is sufficiently small, and the appearance of each color becomes substantially uniform. The visibility becomes clear in the entire visible light wavelength range.

  The antireflection film 2 is provided on at least one surface of the glass substrate 1 (surface used as a light transmitting surface). A glass article 3 shown in FIG. 1 is an example in which an antireflection film 2 is provided on one main surface 1a of two opposing main surfaces 1a and 1b of a glass substrate 1. The antireflection film 2 may be formed as the same or different film on a plurality of surfaces as required.

  The configuration is not particularly limited as long as the antireflection film 2 is formed on the surface of the glass substrate 1 and the glass article 3 can be matched with the conditions of the present invention. The antireflection film 2 may be a single layer film composed of only one layer or an optical multilayer film in which two or more layers are laminated. Moreover, if the antireflection film 2 is formed on the surface of the glass substrate 1 and can match the glass article 3 with the conditions of the present invention, for example, infrared shielding, ultraviolet shielding, antifouling, dustproof, durable It may be a film having other functions such as property improvement.

  When the antireflection film 2 is an optical multilayer film, the number of layers is preferably 8 or less. If the number of layers of the optical multilayer film exceeds 8, the manufacturing cost may increase, or the overall thickness of the glass article 3 may increase, making it difficult to utilize for a small device or the like. The number of layers of the antireflection film 2 is more preferably 6 or less.

In the case where the antireflection film 2 is an optical multilayer film, typically, a dielectric in which a low refractive index dielectric film (low refractive index film) and a high refractive index dielectric film (high refractive index film) are alternately laminated. Body multilayer film. The high refractive index film preferably has a refractive index of 1.6 or more, more preferably 2.2 to 2.5. Examples of the material for the high refractive index film include Ta ₂ O ₅ , TiO ₂ , and Nb ₂ O ₅ . Among these, Nb ₂ O ₅ is preferable because desired optical characteristics can be obtained when an optical multilayer film is formed.

On the other hand, the low refractive index film preferably has a refractive index of less than 1.6, more preferably 1.45 or more and less than 1.55. Examples of the material for the low refractive index film include SiO ₂ and SiO _x N _y . From the viewpoint of reproducibility, stability, economical efficiency, etc. in film formability, SiO ₂ is preferable.

That is, when the antireflective film 2 is an optical multilayer film, it is preferably a film including an alternately laminated portion of a silicon oxide (SiO ₂ ) layer and a niobium oxide (Nb ₂ O ₅ ) layer. In the example illustrated in FIG. 1, the antireflection film 2 included in the glass article 3 is an optical multilayer film in which six layers to which reference numerals 21 to 26 are attached in order from the glass substrate 1 side. The antireflection film 2 is, for example, Nb ₂ O ₅ layer 21, SiO ₂ layer 22, Nb ₂ O ₅ layer 23, SiO ₂ layer 24, Nb ₂ O ₅ layer 25 in order from the main surface 1 a side of the glass substrate 1. , The structure of the SiO ₂ layer 26.

The antireflection film 2 may have a five-layer structure of SiO ₂ layer / Nb ₂ O ₅ layer / SiO ₂ layer / Nb ₂ O ₅ layer / SiO ₂ layer in order from the main surface 1a side of the glass substrate 1. . The laminated structure of the antireflection film 2 can be appropriately changed according to the required physical properties.

  When the antireflection film 2 is an optical multilayer film, the thickness of each layer (film thickness per layer) can be set to 5 nm to 200 nm, respectively. The reflectance of light incident from the surface 2a of the antireflection film 2 in the glass article 3 by appropriately adjusting the material (refractive index), film thickness, stacking order on the glass substrate 1, etc. of each layer in the antireflection film 2 The antireflection film 2 having the function of setting the average reflectance of light in the first wavelength region to be lower than the average reflectance of light in the entire visible light wavelength region and 0.5% or less can be designed. In this specification, the thickness of each layer of the optical multilayer film and the thickness of the entire film are optical film thicknesses unless otherwise specified. The optical film thickness can be calculated, for example, from the results of measurement using FE3000 manufactured by Otsuka Electronics Co., Ltd.

  In the antireflection film 2, by setting the upper limit of the film thickness per layer to 200 nm, it is possible to suppress a decrease in visible light transmittance. The reason why the film thickness of one layer of the antireflection film 2 is 5 nm or more is that the antireflection film 2 actually exists in the form of a film and sufficiently exhibits its function.

  The total thickness of the antireflection film 2 is preferably 200 to 450 nm. When the thickness of the antireflection film 2 exceeds 450 nm, it may be difficult to utilize it for a small device or the like due to an increase in manufacturing cost or an increase in the thickness of the entire glass article 3. The thickness of the antireflection film 2 is preferably 430 nm or less, and more preferably 400 nm or less. Moreover, when the thickness of the antireflection film 2 is less than 200 nm, it may be impossible to obtain reflection characteristics necessary for improving the transmittance of the glass substrate 1. The thickness of the antireflection film 2 is preferably 210 nm or more, and more preferably 220 nm or more.

  The antireflection film 2 can be formed on the glass substrate 1 by a known film formation method. Specifically, it is formed using a film forming method such as a heat evaporation method, a sputtering method, or an ion assisted deposition (IAD) method. In particular, when a highly scratch-resistant film is formed as the antireflection film 2, it is preferable to use a sputtering method or an ion-assisted vapor deposition method so that a dense film can be obtained.

  The glass article 3 including the glass substrate 1 and the antireflection film 2 has been described above with reference to FIG. The glass article 3 can change the design of the glass substrate 1 and the antireflection film 2 as long as the effects of the present invention are not impaired. Moreover, the glass article 3 may have members other than the glass substrate 1 and the antireflection film 2 as long as the effects of the present invention are not impaired.

  For example, the glass article 3 may have an adhesion reinforcing film layer for enhancing the adhesion between the glass substrate 1 and the antireflection film 2 between the glass substrate 1 and the antireflection film 2. The glass article 3 may have an ultraviolet absorption layer, an ultraviolet reflection layer, or the like for reducing damage to the glass substrate 1 due to ultraviolet rays in addition to the adhesion reinforcing film layer. These ultraviolet absorbing layer and ultraviolet reflecting layer may be provided, for example, between the glass substrate 1 and the antireflection film 2, and provided between the multilayer films if the antireflection film 2 is an optical multilayer film. May be. In any case, the ultraviolet absorbing layer and the ultraviolet reflecting layer are designed to contribute to the antireflection ability of the antireflection film 2 as a part of the antireflection film 2 while having the ultraviolet absorption ability and ultraviolet reflection ability of the layer itself. There may be.

  The glass article of the present invention is a glass article in which an antireflection film is formed on a glass substrate having a specific wavelength range with low transmittance in the visible light wavelength range, and the transmittance of the glass substrate is in the visible wavelength range. It is a glass article having a high transmittance which is increased so as to be substantially uniform over the entire area. Therefore, the glass article of the present invention is required to have a property that the transmittance in the visible light wavelength region is uniformly high over the entire region, for example, LCD (Liquid Crystal Display), LCOS (Liquid Crystal On Silicon), OLED (Organic Light Emitting Diode). ), Image display devices such as MEMS (Micro Electro Mechanical System) displays and electronic paper.

  Hereinafter, the present invention will be described in more detail by way of examples. The present invention is not limited to the embodiments and examples described below. Examples 1 and 2 are examples, and examples 3 and 4 are comparative examples. Example 5 is a glass substrate (reference example).

[Examples 1-4]
A glass article 3 including a glass substrate 1 and an antireflection film 2 provided on one main surface 1a of the glass substrate 1 shown in FIG. 1 was produced. However, the number of layers of the antireflection film 2 was the number of layers described below for each example.

  As the glass substrate 1, a non-alkali aluminosilicate glass (Asahi Glass Co., Ltd.) substrate (thickness 0.9 mm) was used. Example 5 is the glass substrate itself. On one main surface 1a of the glass substrate 1, an antireflection film 2 having a layer structure (material and film thickness of each layer) shown in Table 1 is formed by a sputtering method to obtain glass articles of Examples 1 to 4. It was. In Table 1, the first layer is a layer in contact with the main surface 1 a of the glass substrate 1. In addition, the film thickness of each layer of the antireflection film 2 is calculated from the result of measurement with an FE3000 manufactured by Otsuka Electronics Co., Ltd.

  About the obtained glass article of each example and the glass base material of Example 5, the reflectance and transmittance | permeability of the light in wavelength 300-800 nm were measured as follows.

(Reflectance)
The reflectance was measured by irradiating light from the surface 2a side of the antireflection film 2 for the glass article 3 and from the main surface 1a side for the glass substrate 1 using an FE3000 manufactured by Otsuka Electronics Co., Ltd. The obtained measured value was used for evaluation as the reflectance as it was.

(Transmittance)
Using U4100 manufactured by Hitachi, Ltd., the transmittance of the glass article 3 was measured on the main surface 1b side of the glass substrate 1 for light incident from the surface 2a of the antireflection film 2. About the glass base material 1, the transmittance | permeability was measured in the main surface 1b side of the glass base material 1 of the light which injects from the main surface 1a of the glass base material 1. FIG.

[Optical properties of glass substrate]
About the glass base material (Example 5) used for the glass article of each example, the whole average transmittance (henceforth Tag) of wavelength 400-700 nm (visible light wavelength range) was 91.53%. . Moreover, the 1st wavelength range which has an average transmittance | permeability lower than Tag exists in wavelength 400-500 nm, and the average transmittance (henceforth Tbg) in wavelength 400-500 nm was 91.23%. The average transmittance in the first wavelength region was 0.30% lower than the average transmittance in the entire visible light wavelength region. That is, the difference between Tag and Tbg represented by Tag−Tbg (hereinafter represented by Tdg) was 0.30%. FIG. 6A shows the relationship between the wavelength of the glass substrate (Example 5) and the transmittance.

  The overall average reflectance (hereinafter referred to as Rag) of the glass substrate (Example 5) having a wavelength of 400 to 700 nm (visible light wavelength range) is 7.85%, and the first wavelength range (wavelength 400 to 500 nm). ) Was 8.46% (hereinafter referred to as Rbg). The relationship between the wavelength of the glass substrate (Example 5) and the reflectance is shown in FIG. 6B. Table 1 shows the transmittance characteristics and reflectance characteristics of the glass substrate (Example 5).

[Evaluation of optical properties of glass articles of Examples 1 to 4]
About the glass articles of Examples 1 to 4, the average transmittance at a wavelength of 400 to 700 nm (hereinafter referred to as Ta), the average transmittance at a wavelength of 400 to 500 nm (hereinafter referred to as Tb), the difference between the two indicated by Ta-Tb (Hereinafter referred to as Td), an average reflectance at a wavelength of 400 to 700 nm (hereinafter referred to as Ra), an average reflectance at a wavelength of 400 to 500 nm (hereinafter referred to as Rb), and a difference between both indicated by Ra-Rb ( Hereinafter, the minimum transmittance and the maximum transmittance at wavelengths 400 to 700, and the difference between the maximum transmittance and the minimum transmittance were calculated. The results are shown in Table 1 together with the configuration of the antireflection film 2.

  Furthermore, the difference (Ta-Tag) shows the degree of improvement in the average transmittance of the entire visible light wavelength region in the glass article compared to the average transmittance of the entire visible light wavelength region in the used glass substrate. Moreover, the difference (Td) between the average transmittance of the entire visible light wavelength region in the glass article and the average transmittance of the first wavelength region, the average transmittance of the entire visible light wavelength region in the used glass substrate, and the first Comparison with the difference in the average transmittance in the wavelength region (Tdg) is shown as the difference between them (Td−Tdg). The results are shown in Table 1.

  The relationship between the wavelength and the transmittance in the glass articles of Examples 1 to 4 is shown in FIGS. 2A, 3A, 4A, and 5A, respectively. “Uncoated” indicated by a broken line in each figure is the transmittance of the glass substrate of Example 5. The relationship between the wavelength and the reflectance in the glass articles of Examples 1 to 4 is shown in FIGS. 2B, 3B, 4B, and 5B, respectively.

  From Table 1, the glass articles obtained in Examples 1 and 2 are glass groups having a specific wavelength range (first wavelength range; 400 to 500 nm in each of the above examples) having a low transmittance in the visible wavelength range. A glass article in which an antireflection film is formed on a material, and the reflectance of light incident from the surface of the antireflection film in the glass article is such that the average reflectance of light in the first wavelength range is the entire visible wavelength range It can be seen that it is lower than the average reflectance of light (Rb <Ra) and 0.5% or less.

  Thereby, as shown in Table 1, the glass articles obtained in Examples 1 and 2 are different in the average transmittance (Ta) of the entire visible light wavelength region and the average transmittance (Tb) of the first wavelength region. (Td) is equal to or less than the difference (Tdg) between the two in the glass substrate used. Furthermore, the average transmittance (Ta) of the entire visible light wavelength region in the glass articles obtained in Examples 1 and 2 is 3% or more compared to the average transmittance (Tag) of the entire visible light wavelength region of the glass substrate. high. Thus, the glass article obtained in Example 1 and Example 2 is a glass article having a high transmittance that is increased so that the transmittance of the glass substrate is substantially uniform over the entire visible wavelength range. Recognize.

  On the other hand, in the glass articles obtained in Examples 3 and 4, the average reflectance of light in the first wavelength range incident from the surface of the antireflection film in the glass article is 0.5% or less. It can be seen that the average reflectance of light in the entire visible light wavelength region incident from the surface of the light is higher (Rb> Ra). Thereby, as shown in Table 1, the glass articles obtained in Examples 3 and 4 are different in the average transmittance (Ta) of the entire visible light wavelength region and the average transmittance (Tb) of the first wavelength region. (Td) is greater than the difference (Tdg) between the two glass substrates used, and the average transmittance (Ta) of the entire visible light wavelength region in the glass articles obtained in Examples 3 and 4 is Although it is higher than the average transmittance (Tag) of the entire visible light wavelength region in the material, the difference is small.

  1: glass substrate, 2: antireflection film, 3: glass article

Claims (7)

A glass article having a glass substrate and an antireflection film provided on at least one surface of the glass substrate,
The glass substrate has an average transmittance of light in a visible light wavelength region of 400 to 700 nm incident from the surface, which is lower than an average transmittance of the entire visible light wavelength region in the visible light wavelength region. Having a distribution having a wavelength range of 1;
Regarding the reflectance of light incident from the surface of the antireflection film in the glass article, the average reflectance of light in the first wavelength region is lower than the average reflectance of light in the entire visible light wavelength region, and 0. A glass article characterized by being 5% or less.   The first wavelength region is a wavelength region of 400 to 500 nm, and an average transmittance of light in the first wavelength region incident on the surface of the glass substrate is 85 to 92%. The glass article according to claim 1.   The glass article according to claim 1, wherein the antireflection film is an optical multilayer film.   The glass article according to claim 3, wherein the number of layers of the optical multilayer film is 8 or less. The glass article according to claim 3 or 4, wherein the optical multilayer film includes an alternately laminated portion of an SiO ₂ layer and an Nb ₂ O ₅ layer.   The glass article according to any one of claims 1 to 5, wherein the antireflection film has a thickness of 200 to 450 nm.   In the transmittance of light in the visible light wavelength range incident on the glass article so as to pass through the antireflection film, the average transmittance is 93% or more, and the difference between the maximum value and the minimum value is 2% or less. The glass article according to any one of claims 1 to 6.

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