Multilayer structure and process for producing the same

• US 6,436,542 B1
• Filed: 07/11/2000
• Issued: 08/20/2002
• Est. Priority Date: 07/14/1999
• Status: Expired due to Fees

• Current Assignee: Nippon Sheet Glass Company Limited (Nippon Telegraph and Telephone Corporation)
• Original Assignee: Nippon Sheet Glass Company Limited (Nippon Telegraph and Telephone Corporation)
• Inventors: Mori, Kenji, Inomata, Hiroyuki, Kijima, Yoshifumi, Doushita, Kazuhiro, Ogino, Etsuo, Kawahara, Tetsuro
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): Piziali, Andrew T
• Application Number:
  US09/613,726
• Time in Patent Office: 770 Days
• Field of Search: 428/426, 428/428, 428/432, 428/448, 428/702, 428/697
• US Class Current: 428/432
• CPC Class Codes: B01J 35/30 characterised by their physical properties
• CPC Class Codes: B01J 35/39 Photocatalytic properties
• CPC Class Codes: B01J 37/347 Ionic or cathodic spraying; Electric discharge
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/71 Photocatalytic coatings
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy

Abstract

A conductive sinter obtained from a mixture of titanium oxide particles and 2.5% by weight niobium oxide particles is used as a target in direct current sputtering to form a photocatalytically active film mainly comprising titanium oxide on a glass substrate. The target has a surface resistance of 500 Ω/□ or lower and the sputtering is conducted while heating the substrate at 230° C. The photocatalytically active film is based on an amorphous matrix. This process is free from problems of a conventional process in which a photocatalytically active titanium oxide film is deposited by reactive sputtering using titanium metal as a target. The problems are that the substrate needs to be heated to 350° C. or higher and that the deposited film does not have high photocatalytic activity.

Claims

1. A multilayer structure comprising a substrate and formed thereon a film mainly comprising titanium oxide and having photocatalytic activity, said film containing as a minor component at least one metal oxide selected from the group consisting of niobium oxide, tantalum oxide, vanadium oxide, zirconium oxide, tin oxide, chromium oxide and copper oxide, and being substantially amorphous when analyzed by the X-ray diffraction method.

2. The multilayer structure as claimed in claim 1, wherein the substantially amorphous film mainly comprising titanium oxide comprises an amorphous matrix containing microcrystals.

3. The multilayer structure as claimed in claim 1, wherein the content of the metal oxide as the minor component in the film mainly comprising titanium oxide is from 1 to 10% by weight.

4. The multilayer structure as claimed in claim 3, wherein the metal oxide as the minor component is niobium oxide.

5. The multilayer structure as claimed in claim 1, which has, interposed between the substrate and the film mainly comprising titanium oxide, a primer film which serves to prevent any alkali component of the substrate from dissolving in the film mainly comprising titanium oxide.

6. The multilayer structure as claimed in claim 1, wherein the film mainly comprising titanium oxide is coated with a hydrophilic film.

7. The multilayer structure as claimed in claim 6, which has, interposed between the substrate and the film mainly comprising titanium oxide, a primer film which serves to prevent any alkali component of the substrate from dissolving in the film mainly comprising titanium oxide, wherein the primer film and the hydrophilic film each is a film of silicon dioxide.