Antistatic coating for video display screen

• US 5,580,662 A
• Filed: 03/09/1995
• Issued: 12/03/1996
• Est. Priority Date: 03/09/1995
• Status: Expired due to Term

• Current Assignee: Chunghwa Picture Tubes Limited
• Original Assignee: Chunghwa Picture Tubes Limited
• Inventors: Yu, Yu-Chung, Tong, Hua-Sou, Hu, Chung-Min
• Primary Examiner(s): TURNER, ARCHENE A
• Application Number:
  US08/400,926
• Time in Patent Office: 635 Days
• Field of Search: 428/432, 428/688, 428/689, 428/702, 428/704, 428/426, 428/323, 428/325, 428/328, 252/500, 252/518, 313/478, 313/479, 427/126.1, 427/126.2, 427/126.3, 427/164, 427/165
• US Class Current: 428/432
• CPC Class Codes: H01J 29/868 Screens covering the input or output face of the vessel, e.g. transparent anti-static coatings, X-ray absorbing layers
• CPC Class Codes: Y10T 428/25 Web or sheet containing structurally defined element or component and including a second component containing structurally defined particles
• CPC Class Codes: Y10T 428/252 Glass or ceramic [i.e., fired or glazed clay, cement, etc.] [porcelain, quartz, etc.]
• CPC Class Codes: Y10T 428/256 Heavy metal or aluminum or compound thereof

Abstract

An antistatic coating for the outer surface of a video display panel such as of a cathode ray tube (CRT), and a method of applying this type of surface coating, employs a conventional antistatic material such as antimony doped tin oxide to which is added a solvent which is (1) soluble in water and alcohol, (2) has an evaporation point higher than that of water, and (3) has greater solubility for oil-based contaminants than for water. Solvents having these characteristics and which are adapted for use in the antistatic coating include ethylene glycol and dimethyl-based solvents, and their derivatives. The antistatic coating has reduced susceptibility to picking up surface contaminants such as dust and wiping residues such as applied in cleaning the display panel, particularly during manufacture, while affording a high degree of static charge dissipation.

Claims

1. A video apparatus comprising:

a display panel having an outer and an inner surface; and

an antistatic coating layer disposed on the outer surface of said display panel, said coating layer comprised of a conductive metal oxide, an organic solvent and a non-alcohol solvent having a dimethyl amide group or dimethyl sulfide group, or a derivative thereof, wherein said antistatic coating layer is comprised of 5-20 wt. % of said non-alcohol solvent, or derivative thereof, and wherein said non-alcohol solvent, or derivative thereof, is (1) soluble in water and alcohol, (2) has an evaporation point higher than that of water, and (3) has greater solubility for oil-based contaminants than for water.

2. The video display apparatus of claim 1 wherein said antistatic layer further comprises 10 wt. % water and 1 wt. % of said conductive metal oxide.

3. The video display apparatus of claim 1 wherein said derivative of said non-alcohol solvent is selected from the group consisting of dimethyl formamide, dimethyl sulfoxide, and dimethyl acetamide.

4. The video display apparatus of claim 1 wherein said organic solvent is an alcohol or alcohol mixture.

5. The video display apparatus of claim 4 wherein said organic solvent is ethanol or isopropanol, or a mixture of ethanol and isopropanol.

6. The video display apparatus of claim 1 wherein said display panel is a field emission display, a plasma discharge panel, a vacuum florescent screen, or a gas discharge screen.

7. The video display apparatus of claim 1 wherein said conductive metal oxide is antimony doped tin oxide.