KR102191162B1 - Photochromic glass - Google Patents

Abstract

The photochromic glass according to an embodiment of the present invention is provided on one surface of the photochromic layer and the photochromic layer in which the visible light transmittance decreases in short wavelength light and the visible light transmittance increases in long wavelength light. A short wavelength transmission layer that transmits only short wavelength light among the light, a wavelength conversion layer that is provided on the other side opposite to the photochromic layer and converts the wavelength of light incident toward the photochromic layer into a long wavelength, or light incident toward the photochromic layer It includes a long-wavelength transmission layer that transmits only medium-long wavelength light. The visible light transmittance of the photochromic layer can be adjusted through the incident direction of light on both sides opposite to the photochromic layer. Various colors can be implemented according to the photochromic layer, and the short-wavelength transmission layer can be used as an insulating function by blocking infrared rays.

Description

Photochromic glass {PHOTOCHROMIC GLASS}

The present invention relates to a photochromic glass, and more particularly, to a photochromic glass that is switched by irradiation of selective light.

Most functional windows used today use electrochromic devices whose transmittance changes according to the applied voltage. Since a general electrochromic device uses an electrolyte, it is difficult to apply to windows and doors, and there are problems in stability and reaction time. Therefore, when light of a specific wavelength is irradiated, it is necessary to develop a photochromic device that exhibits a characteristic of reducing the transmittance of visible light due to a change in the molecular structure. The photochromic layer for a photochromic device is mostly organic and causes photochromic in response to ultraviolet rays. In addition, since stability at room temperature is recently secured, organic dyes that maintain a photochromic state before applying light of different wavelengths have been developed.

An object to be solved of the present invention is to add a light switching function to a photochromic glass.

The problem to be solved by the present invention is not limited to the problems mentioned above, and other problems that are not mentioned will be clearly understood by those skilled in the art from the following description.

A photochromic glass for solving the above-described technical problems is provided. The photochromic glass according to an embodiment of the present invention includes a photochromic layer, a short-wavelength transmissive layer that is disposed on the first surface of the photochromic layer and has a higher transmittance for light of a shorter wavelength than a long wavelength, and the first of the photochromic layer It is disposed on the second surface opposite the surface and includes a wavelength conversion layer for converting light of a short wavelength into light of a long wavelength.

For example, the photochromic layer may increase absorbance of visible light when irradiated with ultraviolet rays, and increase transmittance when irradiating near infrared rays.

For example, the photochromic layer is azobenzene, spiro-naphtoxazine, naphtopyran, spiropyran, furylfulgide, stilbene ), nitron, fulgide, triarylmethane, diarylethene, MoO _x , or WO _x .

The short wavelength transmission layer has a thickness of less than 500 nm, and may include a transparent electrode selected from ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ and V ₂ O ₅ .

The short-wavelength transmission layer may be a multilayer optical functional thin film including an insulator having a thickness of less than 500 nm and an ultra-thin metal. The insulator may be selected from ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ and V ₂ O ₅ . The ultra-thin metal may be selected from Ag, Cu, Al, Au, Pt, Zn, Cr, and Mo.

The wavelength conversion layer may include an organic dye, a lanthanide inorganic thin film, TiO _x or ZnO _x .

The photochromic glass according to another embodiment of the present invention includes a photochromic layer, a short-wavelength transmissive layer that is disposed on the first surface of the photochromic layer and has a higher transmittance for light of a shorter wavelength than that of a longer wavelength, and the photochromic layer. It is disposed on the second surface opposite the first surface and includes a long-wavelength transmission layer that absorbs and blocks short-wavelength light.

For example, the photochromic layer may increase absorbance of visible light when irradiated with ultraviolet rays, and increase transmittance when irradiating near infrared rays.

For example, the photochromic layer is azobenzene, spiro-naphtoxazine, naphtopyran, spiropyran, furylfulgide, stilbene ), nitron, fulgide, triarylmethane, diarylethene, MoO _x , or WO _x .

The short wavelength transmission layer has a thickness of less than 500 nm, and may include a transparent electrode selected from ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ and V ₂ O ₅ .

The short-wavelength transmission layer may be a multilayer optical functional thin film including an insulator having a thickness of less than 500 nm and an ultra-thin metal. The insulator may be selected from ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ and V ₂ O ₅ . The ultra-thin metal may be selected from Ag, Cu, Al, Au, Pt, Zn, Cr, and Mo.

The long-wavelength transmission layer may include a light absorbing material having a band gap of 1.5 to 2.5 eV. The light absorbing material may include amorphous silicon, microcrystalline silicon, amorphous silicon-germanium, CIGS, CdTe, GaAs, INP, SiC, SiN, or SiO.

The long-wavelength transmission layer may further include a dielectric selected from ITO, ZnO:Al, ZnO:Ga, SnO ₂ , ZnO, TiO ₂ , Al ₂ O ₃ , SiO ₂ and ZrO ₂ .

The long-wavelength transmission layer may be an inorganic thin film having a thickness of 20 to 500 nm.

Photochromic glass according to embodiments of the present invention includes a photochromic layer.

Light of a specific wavelength may change the transmittance of the photochromic layer. The wavelength range of the incident component can be controlled by the short wavelength transmission layer, the wavelength conversion layer, and the long wavelength transmission layer. When the wavelength of the incident component is shortened, the visible light transmittance of the photochromic layer decreases. The incident short wavelength light is limited to the short wavelength transmission layer. Further, as the wavelength of the incident component increases, the visible light transmittance of the photochromic layer increases. The incident long wavelength light is limited to the wavelength conversion layer or the long wavelength transmission layer. Therefore, the transmittance of the photochromic layer can be adjusted according to the incident direction of light.

For a more complete understanding and assistance of the present invention, references are given in the following description along with the accompanying drawings and reference numerals have been given hereinafter.
1 is a graph showing characteristics of a photochromic layer according to embodiments of the present invention.
2 is a cross-sectional view showing a photochromic glass according to an embodiment of the present invention.
3 is a graph of a change in transmittance according to a wavelength of a short-wavelength transmission layer according to an embodiment of the present invention.
4 is a graph of wavelength conversion characteristics according to wavelengths of a wavelength conversion layer according to an embodiment of the present invention.
5 is a cross-sectional view showing a photochromic glass according to another embodiment of the present invention.
6 is a graph of a change in transmittance according to a wavelength of a long-wavelength transmission layer according to another embodiment of the present invention.
7 is a view showing a principle of coloring and discoloration of light-switching discoloration sunglasses according to embodiments of the present invention.
8 is a view showing the principle of coloring and discoloration of light-switching discoloration windows for buildings according to embodiments of the present invention.
9 is a view showing the principle of coloring and discoloration of a light-switching vehicle color change window according to embodiments of the present invention.

In order to fully understand the configuration and effects of the present invention, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and may be implemented in various forms and various modifications may be made. However, it is provided to complete the disclosure of the present invention through the description of the present embodiments, and to fully inform the scope of the present invention to those of ordinary skill in the art. Those of ordinary skill in the art will understand that the inventive concept may be practiced in any suitable environment.

The terms used in the present specification are for describing exemplary embodiments and are not intended to limit the present invention. In this specification, the singular form also includes the plural form unless specifically stated in the phrase. As used in the specification,'comprises' and/or'comprising' refers to the presence of one or more other elements, steps, actions and/or elements, and/or elements, steps, actions and/or elements mentioned. Or does not exclude additions.

Where a side (or layer) is referred to herein as being on the other side (or layer) or substrate it may be formed directly on the other side (or layer) or substrate, or a third side ( Or a layer) may be interposed.

In various embodiments of the present specification, terms such as first, second, and third are used to describe various regions, faces (or layers), and the like, but these regions and faces should not be limited by these terms. do. These terms are only used to distinguish one area or surface (or layer) from another area or surface (or layer). Accordingly, the side referred to as the first side in one embodiment may be referred to as the second side in another embodiment. Each embodiment described and illustrated herein also includes its complementary embodiment. Parts marked with the same reference numbers throughout the specification represent the same elements.

Terms used in the embodiments of the present invention may be interpreted as meanings commonly known to those of ordinary skill in the art, unless otherwise defined.

Hereinafter, the present invention will be described in detail by describing preferred embodiments of the present invention with reference to the accompanying drawings.

The concept of the present invention relates to a photochromic glass whose transmittance is controlled by light. Preferably, the photochromic glass according to the embodiments of the present invention includes a photochromic layer, and the photochromic layer is sandwiched between two layers that transmit light of opposite wavelengths (eg, ultraviolet rays and near infrared rays). Lose.

Referring to FIG. 1, the photochromic layer increases the absorption of visible light when irradiated with short wavelength light λ _on (eg, ultraviolet), and transmittance when irradiated with long wavelength light λ _off (eg, near infrared). It has an increasing photochromic property. For example, when a photochromic layer is irradiated with light (λ _on ) of a short wavelength, the absorption of visible light increases. Even if the short wavelength light (λ _on ) irradiated to the photochromic layer is removed, the absorption of visible light remains increased. When a long wavelength light (λ _off ) is irradiated to the photochromic layer, the transmittance of visible light increases. Even when the long wavelength light (λ _off ) irradiated to the photochromic layer is removed, the transmittance of visible light remains increased.

The photochromic layer may include an organic material having photochromic properties. For example, the photochromic layer is azobenzene, spiro-naphtoxazine, naphtopyran, spiropyran, furylfulgide, stilbene ), nitron, fulgide, triarylmethane, or diarylethene. Alternatively, the photochromic layer may be an inorganic oxide. For example, the photochromic layer may be formed of MoO _x or WO _x .

2 is a cross-sectional view showing a photochromic glass according to an embodiment of the present invention.

Referring to FIG. 2, a photochromic glass 10 according to an embodiment of the present invention may include a short wavelength transmission layer 14, a photochromic layer 12, and a wavelength conversion layer 16.

The photochromic layer 12 includes the photochromic layer described with reference to FIG. 1. The photochromic layer 12 has a first surface 12a and a second surface 12b opposed to each other.

The short wavelength transmission layer 14 is formed on the first surface 12a of the photochromic layer 12. 3 is a graph of the change in transmittance according to the wavelength of the short-wavelength transmission layer 14. Referring to FIG. 3, the short wavelength transmission layer 14 may have high transmittance at a short wavelength. The short-wavelength transmission layer 14 may reflect or absorb light of a long wavelength, thereby having a low transmittance at a long wavelength. For example, at a long wavelength of 700 nm or more, the transmittance may be very low, such as 50% or less. The short wavelength transmission layer 14 may have directionality. For example, the short wavelength transmission layer 14 may have different transmittance or reflectivity depending on the incident direction of light.

The short-wavelength transmission layer 14 may include a transparent electrode having a thickness of less than 500 nm. For example, the transparent electrode may include ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ or V ₂ O ₅ . The short wavelength transmission layer 14 may be a multilayer optical functional thin film having a thickness of less than 500 nm. The multilayer optical functional thin film may include an insulator or an ultra-thin metal. For example, the insulator may include ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ or V ₂ O ₅ . For example, the ultra-thin metal may include Ag, Cu, Al, Au, Pt, Zn, Cr or Mo.

Since the short-wavelength transmission layer 14 is disposed on the first surface 12a of the photochromic layer 12, only the short-wavelength light λ _on among natural light is irradiated to the photochromic layer 12. The short wavelength transmission layer 14 serves as a switch to lower the visible light transmittance of the photochromic layer 12.

The wavelength conversion layer 16 is formed on the second surface 12b of the photochromic layer 12. 4 is a graph of wavelength conversion characteristics according to the wavelength of the wavelength conversion layer 16. Referring to FIG. 4, the wavelength conversion layer 16 converts light of a short wavelength into light of a long wavelength (λ _off ). The wavelength conversion layer 16 transmits light of a long wavelength (λ _off ) and converts light of a short wavelength (λ _on ) into light of a long wavelength.

The wavelength conversion layer 16 may include an organic dye, a lanthanide inorganic thin film, TiO _x or ZnO _x . For example, organic dyes include metal oxinoid compounds, stilbene compounds, anthracine compounds, oxadiazole metal chelate compounds, polyfluorenes, and polyfluorene compounds. It may be selected from phenylenevinylenes and mixtures thereof. For example, the lanthanide inorganic thin film may be a compound containing a lanthanide cation and a derivative thereof.

Since the wavelength conversion layer 16 is disposed on the second surface 12b of the photochromic layer 12, only light of a long wavelength λ _off among natural light is irradiated to the photochromic layer 12. The wavelength conversion layer 16 serves as a switch to increase the visible light transmittance of the photochromic layer 12.

5 is a cross-sectional view showing a photochromic glass 20 according to another embodiment of the present invention

Referring to FIG. 5, a photochromic glass 20 according to another embodiment of the present invention may include a short wavelength transmission layer 24, a photochromic layer 22, and a long wavelength transmission layer 26.

The photochromic layer 22 may be a photochromic layer described with reference to FIG. 1. The photochromic layer 22 has a first surface 22a and a second surface 22b opposed to each other.

The short wavelength transmission layer 24 is formed on the first surface 22a of the photochromic layer 22. As described with reference to FIG. 3, the short-wavelength transmission layer 24 may reflect or absorb long-wavelength light, thereby having a low transmittance at a long wavelength. The short wavelength transmission layer 14 may have directionality. For example, the short wavelength transmission layer 14 may have different transmittance or reflectivity depending on the incident direction of light.

The short wavelength transmission layer 24 may include a transparent electrode having a thickness of less than 500 nm. For example, it may include ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ or V ₂ O ₅ . The short wavelength transmission layer 24 may be a multilayer optical functional thin film having a thickness of less than 500 nm. The multilayer optical functional thin film may include an insulator or an ultra-thin metal. For example, the insulator may include ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ or V ₂ O ₅ . For example, the ultra-thin metal may include Ag, Cu, Al, Au, Pt, Zn, Cr or Mo.

Since the short-wavelength transmission layer 24 is disposed on the first surface 22a of the photochromic layer 22, only the short-wavelength light λ _on among natural light is irradiated to the photochromic layer 22. The short wavelength transmission layer 24 serves as a switch to lower the visible light transmittance of the photochromic layer 22.

The long-wavelength transmission layer 26 is formed on the second surface 22b of the photochromic layer 20. 6 is a graph showing a change in transmittance according to the wavelength of the long-wavelength transmission layer 26. Referring to FIG. 6, the long-wavelength transmission layer 26 absorbs short-wavelength light λ _on . The long-wavelength transmission layer 26 may have directionality. For example, the long-wavelength transmission layer 26 may have different transmittance or reflectivity depending on the incident direction of light.

The long-wavelength transmission layer 26 may be an inorganic thin film formed to a thickness of 20 to 500 nm. The inorganic thin film may be made of a light absorbing material having a band gap of 1.5 to 2.5 eV. For example, the light absorbing material may include amorphous silicon, microcrystalline silicon, amorphous silicon-germanium, CIGS, CdTe, GaAs, INP, SiC, SiN, and SiO. The long wavelength transmission layer 26 may further include a dielectric. For example, the dielectric may include ITO, ZnO:Al, ZnO:Ga, SnO ₂ , ZnO, TiO ₂ , Al ₂ O ₃ , SiO ₂ or ZrO ₂ .

Since the long-wavelength transmission layer 26 is disposed on the second surface 22b of the photochromic layer 22, short-wavelength light (λ _on ) is absorbed to block transmission and long-wavelength light (λ _off ) is transmitted. do. Among natural light, only light of a long wavelength λ _on is irradiated to the photochromic layer 22. The long-wavelength transmission layer 26 serves as a switch to increase the visible light transmittance of the photochromic layer 22.

The photochromic layers 12 and 22 according to embodiments of the present invention may have various colors depending on the photochromic layer.

The short-wavelength transmission layers 14 and 24 according to embodiments of the present invention may perform a function of low heat radiation. In other words, the short-wavelength transmission layers 14 and 24 block infrared rays, thereby improving heat blocking efficiency.

In embodiments of the present invention, photochromic glass may be used as sunglasses glass. The photochromic glass on the sunglasses may be arranged such that the short wavelength transmission layers 14 and 24 face the outside direction, and the wavelength conversion layer 16 or the long wavelength transmission layer 26 faces the inside direction.

7 is a diagram illustrating a principle of coloring and decolorizing light-switching discoloration sunglasses as embodiments of the present invention. Referring to FIG. 7, when sunlight is irradiated from the outside to sunglasses having a high visible light transmittance, only short wavelength light λ _off is irradiated to the photochromic layers 12 and 22 by the short wavelength transmitting layers 14 and 24. . Therefore, the visible light transmittance of the photochromic layers 12 and 22 is lowered, and the sunglasses are maintained in a colored state. When light is irradiated to the inner surface of the colored sunglasses for conversion to the bleaching state, only the long-wavelength light (λ _on ) is caused by the wavelength conversion layer 16 or the long-wavelength transmission layer 26. The photochromic layers 12 and 22 ). Accordingly, the visible light transmittance of the photochromic layers 12 and 22 increases, and the sunglasses return to a high transmittance state.

In embodiments of the present invention, photochromic glass may be used as a color changeable window for a building. The photochromic glass on the windows of the building is arranged so that the short-wavelength transmission layers 14 and 24 face the outdoor direction, and the wavelength conversion layer 16 or the long-wavelength transmission layer 26 faces the indoor direction.

8 is a diagram illustrating the principle of coloring and discoloring of light-switching discolored windows for buildings as embodiments of the present invention. Referring to FIG. 8, when sunlight is irradiated from the outside of the building light-switching discoloration window, only the short wavelength light λ _off is irradiated to the photochromic layers 12 and 22 by the short wavelength transmitting layers 14 and 24. Accordingly, the visible light transmittance of the photochromic layers 12 and 22 is lowered, and the light-switching discolored window for a building blocks external sunlight and serves as a shading. Thereafter, when indoor light is irradiated to the building light-switching discoloration window, only the long wavelength light λ _on is irradiated to the photochromic layers 12 and 22 by the wavelength conversion layer 16 or the long wavelength transmission layer 26. Accordingly, the visible light transmittance of the photochromic layers 12 and 22 increases, and the light-switching discoloration window for the building returns to a discolored state.

In embodiments of the present invention, the photochromic glass may be used as a car color changeable window. In the photochromic glass on a vehicle window, the short-wavelength transmitting layers 14 and 24 are arranged to direct the outdoor direction, and the wavelength conversion layer 16 or the long-wavelength transmitting layer 26 is arranged to direct the indoor direction.

9 is a diagram illustrating a principle of coloring and discoloring a window of an automobile light-switching discoloration according to embodiments of the present invention. Referring to FIG. 9, when sunlight is irradiated from the outside of the car light-switching color change window, only the short wavelength light λ _off is irradiated to the photochromic layers 12 and 22 by the short wavelength transmission layers 14 and 24. Therefore, the visible light transmittance of the photochromic layers 12 and 22 is lowered, and the car light-switching discoloration window blocks external sunlight and functions as a shade. Thereafter, when indoor light is irradiated onto the car light-switching discoloration window, only the long-wavelength light λ _on is irradiated to the photochromic layers 12 and 22 by the wavelength conversion layer 16 or the long-wavelength transmission layer 26. Accordingly, the visible light transmittance of the photochromic layers 12 and 22 increases, and the vehicle light-switching discoloration window returns to a discolored state.

In the above, embodiments of the present invention have been described with reference to the accompanying drawings, but those of ordinary skill in the art to which the present invention pertains can be implemented in other specific forms without changing the technical spirit or essential features. You can understand that there is. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not limiting.

Claims (20)

A photochromic layer that increases the absorption of visible light when irradiated with ultraviolet rays and increases the transmittance when irradiation with near infrared rays;
A short-wavelength transmission layer disposed on the first surface of the photochromic layer and having a high transmittance for light having a short wavelength compared to a long wavelength; And
A photochromic glass comprising a wavelength conversion layer disposed on a second surface of the photochromic layer opposite to the first surface and converting light of a short wavelength into a long wavelength. The method of claim 1,
The photochromic layer is azobenzene, spiro-naphtoxazine, naphtopyran, spiropyran, furylfulgide, stilbene, age Tron (nitron), fulgide (fulgide), triarylmethane, diarylethene (diarylethene), MoO _x , or photochromic glass containing WO _x . The method of claim 1,
The transmittance or reflectivity of the short wavelength transmission layer is different depending on the light incident on the first surface of the short wavelength transmission layer and the light incident on the second surface of the short wavelength transmission layer opposite to the first surface of the short wavelength transmission layer. Fading glass. The method of claim 1,
The short-wavelength transmission layer has a thickness of less than 500nm, ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ and V ₂ O ₅ Photochromic glass comprising a transparent electrode selected from. The method of claim 1,
The short wavelength transmission layer is a photochromic glass that is a multilayer optical functional thin film having a thickness of less than 500 nm. The method of claim 5,
The multilayer photochromic glass comprising an insulator selected from ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ and V ₂ O ₅ . The method of claim 5,
The multilayer photochromic glass comprising an ultra-thin metal selected from Ag, Cu, Al, Au, Pt, Zn, Cr, and Mo. The method of claim 1,
The wavelength conversion layer is a photochromic glass comprising an organic dye, a lanthanide inorganic thin film, TiO _x or ZnO _x . A photochromic layer that increases the absorption of visible light when irradiated with ultraviolet rays and increases the transmittance when irradiation with near infrared rays;
A short-wavelength transmission layer, which is disposed on the first surface of the photochromic layer and has a higher transmittance for light of a short wavelength than that of a long-wavelength light, and the short-wavelength transmission layer uses light incident to the first surface to transmit visible light of the photochromic layer. Functions as a switch to lower the value; And
It is disposed on a second surface of the photochromic layer opposite to the first surface and includes a long-wavelength transmission layer that absorbs and blocks short-wavelength light, and the long-wavelength transmission layer uses light incident to the second surface to Photochromic glass that functions as a switch to increase the visible light transmittance of the color change layer. The method of claim 9,
The photochromic layer is azobenzene, spiro-naphtoxazine, naphtopyran, spiropyran, furylfulgide, stilbene, age Tron (nitron), fulgide (fulgide), triarylmethane, diarylethene (diarylethene), MoO _x , or photochromic glass containing WO _x . The method of claim 9,
The transmittance or reflectivity of the short wavelength transmission layer is different depending on the light incident on the first surface of the short wavelength transmission layer and the light incident on the second surface of the short wavelength transmission layer opposite to the first surface of the short wavelength transmission layer. Fading glass. The method of claim 9,
The short-wavelength transmission layer has a thickness of less than 500nm, ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ and V ₂ O ₅ Photochromic glass comprising a transparent electrode selected from. The method of claim 9,
The short wavelength transmission layer is a photochromic glass that is a multilayer optical functional thin film having a thickness of less than 500 nm. The method of claim 13,
The multi-layered photofunctional thin film is a photochromic glass comprising an insulator selected from ITO, ZnO:Al, ZnO:Ga, ZnO:B, SnO ₂ , ZnO, TiO ₂ and V ₂ O ₅ . The method of claim 13,
The multilayer photochromic glass comprising an ultra-thin metal selected from Ag, Cu, Al, Au, Pt, Zn, Cr, and Mo. The method of claim 9,
The long-wavelength transmission layer has a transmittance or reflectivity of the long-wavelength transmission layer according to light incident on the first surface of the long-wavelength transmission layer and light incident on the second surface of the long-wavelength transmission layer opposite to the first surface of the long-wavelength transmission layer. Photochromic glass, including others. The method of claim 9,
The long wavelength transmission layer is an inorganic thin film having a thickness of 20 to 500nm photochromic glass. The method of claim 9,
The long-wavelength transmission layer is a photochromic glass comprising a light-absorbing material having a band gap of 1.5 to 2.5 eV. The method of claim 18,
The light absorbing material is amorphous silicon, microcrystalline silicon, amorphous silicon-germanium, CIGS, CdTe, GaAs, INP, SiC, SiN or SiO photochromic glass containing. The method of claim 18,
The long-wavelength transmissive layer is a photochromic glass further comprising a dielectric selected from ITO, ZnO:Al, ZnO:Ga, SnO ₂ , ZnO, TiO ₂ , Al ₂ O ₃ , SiO ₂ and ZrO ₂ .

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