Method for imparting hydrophilicity to substrate

• US 6,667,075 B2
• Filed: 04/12/2002
• Issued: 12/23/2003
• Est. Priority Date: 05/16/2000
• 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: Kitazoe, Toshiaki, Tanaka, Keisuke, Murata, Kenji
• Primary Examiner(s): CAMERON, ERMA C
• Application Number:
  US10/110,642
• Publication Number:
  US 20020192365A1
• Time in Patent Office: 620 Days
• Field of Search: 427/341, 427/342, 427/343, 427/344, 427/353, 427/354, 427/419.2, 427/419.3, 427/419.4
• US Class Current: 427/341
• CPC Class Codes: C03C 17/245 by deposition from the vapour phase
• CPC Class Codes: C03C 17/3417 all coatings being oxide coatings
• CPC Class Codes: C03C 2217/213 SiO2
• CPC Class Codes: C03C 2218/151 by vacuum evaporation
• CPC Class Codes: C03C 2218/152 by cvd
• CPC Class Codes: C03C 2218/32 After-treatment
• CPC Class Codes: C23C 14/10 Glass or silica
• CPC Class Codes: C23C 14/5853 Oxidation
• CPC Class Codes: C23C 16/0272 Deposition of sub-layers, e.g. to promote the adhesion of the main coating
• CPC Class Codes: C23C 16/402 Silicon dioxide
• CPC Class Codes: C23C 16/56 After-treatment
• CPC Class Codes: G02B 1/10 Optical coatings produced by application to, or surface treatment of, optical elements G02B1/08 takes precedence
• CPC Class Codes: G02B 1/18 Coatings for keeping optical surfaces clean, e.g. hydrophobic or photo-catalytic films G02B1/16 takes precedence

Abstract

The present invention relates to a method for imparting hydrophilicity to a substrate whereby high hydrophilic properties and water-holding properties can be maintained for a long period of time. According to the present invention, an SiO₂ film is formed directly or through an undercoat layer on a substrate under a reduced pressure of 100 Pa or less and immediately after the SiO₂ film is formed, the SiO₂ film is treated with water. Before forming the SiO₂ film, it is also desirable that an undercoat layer consisting of a TiO₂ film, Al₂O₃ film, Nb₂O₅ film, a laminated film prepared by laminating the TiO₂ film on the Al₂O₃ film, a laminated film prepared by laminating the TiO₂ film on the Nb₂O₅ film, or a low emissivity film be formed on a substrate and the SiO₂ film be then formed on the undercoat film to serve as an SiO₂ composite film.

Claims

1. A method for imparting to a substrate comprising the steps of forming an SiO₂ film directly or through an undercoat layer on the substrate under a reduced pressure of 100 Pa or less, treating the SiO₂ film with water immediately after formation of the film and forming silanol groups (SiOH) on the surface of the SiO₂ film.

2. The method for imparting hydrophilicity to a substrate according to claim 1, wherein the undercoat layer is selected from the group consisting of a TiO₂ film, an Al₂O₃ film, a Nb₂O₅ film, a laminated film prepared by laminating the TiO₂ film on the Al₂O₃ film, a laminated film prepared by laminating the TiO₂ film on the Nb₂O₅ film, or a low emissivity film.

3. The method for imparting hydrophilicity to a substrate according to claim 2, wherein the low emissivity film comprises a SnO₂ film.

4. The method for imparting hydrophilicity to a substrate according to claim 1, wherein another SiO2 film is formed between the undercoat layer and the substrate.

5. The method for imparting hydrophilicity to a substrate according to claim 3, wherein a laminated film comprising another SiO₂ film on another SnO₂ film is formed between the SnO₂ film undercoat layer and the substrate.

6. The method for imparting hydrophilicity to a substrate according to claim 1, wherein the undercoat layer comprises an SiN film.

7. The method for imparting hydrophilicity to a substrate according to claim 6, wherein the thickness of the SiN film is 1˜

20 nm.

8. The method for imparting hydrophilicity to a substrate according to claim 1, wherein the reduced pressure of 100 Pa or less is characterized in that 1˜

400% of argon or nitrogen is mixed relative to oxygen in oxygen atmospheric gas.

9. The method for imparting hydrophilicity to a substrate according to claim 1, wherein the thickness of the SiO₂ film is performed by sputtering an Si target.

10. The method for imparting hydrophilicity to a substrate according to claim 1, wherein the thickness of the SiO2 film is 1˜

100 nm.

11. The method for imparting hydrophilicity to a substrate according to claim 1, wherein the substrate is a glass substrate which is burned after the water treatment at a temperature of 300˜

500°

C. under an atmosphere in which 0˜

100% nitrogen is mixed relative to air.

12. The method for imparting hydrophilicity to a substrate according to claim 1, wherein 0.1˜

20% by weight of an Al component is doped relative to an Si component in the SiO₂ film.

13. The method for imparting hydrophilicity to a substrate according to claim 1, wherein the substrate provides transparency or a mirror reflection and the transparency or mirror reflection can still be maintained after the hydrophilic treatment.