Window glass employing titanium dioxide photocatalyst

• US 6,939,611 B2
• Filed: 03/22/2002
• Issued: 09/06/2005
• Est. Priority Date: 10/31/1994
• Status: Expired due to Fees

• Current Assignee: Kanagawa Academy of Science and Technology, Nippon Soda Company Limited
• Original Assignee: Kanagawa Academy of Science and Technology, Nippon Soda Company Limited
• Inventors: Fujishima, Akira, Hashimoto, Kazuhito, Iyoda, Tomokazu, Yoshimoto, Tetsuo, Saitoh, Tokuyoshi, Fukayama, Shigemichi
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): BLACKWELL, GWENDOLYN
• Application Number:
  US10/102,819
• Publication Number:
  US 20020107144A1
• Time in Patent Office: 1,264 Days
• Field of Search: 428/403, 428/426, 428/432, 428/685, 428/689, 428/702, 428/701, 502/308, 502/349, 502/350
• US Class Current: 428/432
• CPC Class Codes: A61L 9/205 using a photocatalyst or photosensitiser
• CPC Class Codes: B01D 2255/20707 Titanium
• CPC Class Codes: B01D 2255/802 Photocatalytic
• CPC Class Codes: B01J 21/06 Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 21/063 Titanium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 21/066 Zirconium or hafnium; Oxides or hydroxides thereof
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 37/0244 Coatings comprising several layers
• CPC Class Codes: C03C 17/2456 Coating containing TiO2
• CPC Class Codes: C03C 17/256 Coating containing TiO2
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/212 TiO2
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: H01J 61/35 provided with coatings on the walls thereof; Selection of materials for the coatings using coloured coatings H01J61/40; using luminescent coatings H01J61/42
• CPC Class Codes: H01J 61/42 by transforming the wavelength of the light by luminescence

Abstract

A titanium dioxide film (2) having at least photocatalytic activity, whose light linear transmittance corresponding to light having a wavelength of 550 nm is not less than 50% and whose thickness is 0.1 to 5 μm or so, is formed on a transparent substrate (1) constituted by a glass plate or the like. Preferably, a precoat film (3), which has optical transmissivity and is constituted by a SiO₂ film having a thickness of 0.02 to 0.2 μm or so, is provided between the transparent substrate (1) and the titanium dioxide film (2). Thereby, excellent photocatalytic action and optical transmissivity can be obtained. Moreover, members composing various structures such as a glass window, which are especially required to have optical transparency, can be further provided with photocatalytic activities.

Claims

1. A window glass comprising:

a transparent plate having first and second opposing surfaces and formed of a soda lime glass; and

a titanium dioxide film having a first surface deposited on at least one of the surfaces of said transparent plate, said titanium dioxide film having a photocatalytic activity, a linear transmittance of at least 50% for light having a wavelength of 550 nm and a linear transmittance of 50% or less for light having a wavelength of 350 nm.

2. A window glass according to claim 1 wherein at least 0.5 μ

g of linoleic acid deposited per cm² on a second surface of said titanium dioxide film is decomposed when said titanium dioxide film is irradiated with ultraviolet light, including light in the 300 to 400 nm range at an intensity of 5 mW/cm².

3. A window glass according to claim 1, wherein the thickness of the titanium dioxide film is in the range of approximately 0.1 to 5.0 μ

m.

4. A window glass according to claim 1, wherein the titanium dioxide film contains anatase crystals.

5. A window glass according to claim 1, further comprising a precoat film has a transparency characteristic that is disposed between the transparent plate and the titanium dioxide film.

6. A window glass according to claim 5, wherein the thickness of the precoat film is in the range of approximately 0.02 to 0.2 μ

m.

7. A window glass according to claim 5 wherein the precoat film is made from of one of a silicone dioxide film, a tin oxide film, an indium-doped tin oxide film, an indium oxide film, a tin-doped indium oxide film, a germanium oxide film, an aluminum oxide film, a zirconium oxide film and a SiO₂+metallic oxide film.

8. A window glass according to claim 7, wherein the precoat film is made of a SiO₂+metallic oxide film and the metallic oxide is selected from the group consisting of P₂O₅, B₂O₃, ZrO₂, TiO₂ and Ta₂O₅.

9. A window glass according to claim 7, wherein the precoat film is made of a SiO₂+metallic oxide film in which approximately 5% by weight of P₂O₅ is added to SiO₂.

10. A window glass according to claim 5, wherein the precoat film is made of SiO₂.