Cathode ray tube comprising a display screen having an electroconductive coating

• US 5,742,119 A
• Filed: 08/08/1995
• Issued: 04/21/1998
• Est. Priority Date: 08/08/1994
• Status: Expired due to Fees

• Current Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Original Assignee: US Philips Corporation (Koninklijke Philips N.V.)
• Inventors: Aben, Gerardus V. A., Krings, Leo H. M.
• Primary Examiner(s): Patel, Ashok
• Application Number:
  US08/512,424
• Time in Patent Office: 987 Days
• Field of Search: 313/479, 313/478, 313/480, 313/635, 313/112, 313/313, 359/614, 359/885, 348/834, 348/820
• US Class Current: 313/479
• CPC Class Codes: C03C 17/28 with organic material C03C17/34, C03C17/44 take precedence
• CPC Class Codes: C03C 17/3676 specially adapted for use as electromagnetic shield
• CPC Class Codes: C03C 17/42 at least one coating of an organic material and at least one non-metal coating
• CPC Class Codes: C03C 2217/734 comprising an alternation of high and low refractive indexes
• CPC Class Codes: C08G 61/123 derived from five-membered heterocyclic compounds
• CPC Class Codes: H01B 1/127 comprising five-membered aromatic rings in the main chain, e.g. polypyrroles, polythiophenes
• 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

Abstract

The display screen 3 of a cathode ray tube 1 is provided with an electroconductive coating 8 of poly-3,4-ethylene dioxythiophene. The layer 8 has a sheet resistance of 1 kΩ/□ and a high transmission. The layer 8 provides an effective shield against electromagnetic radiation. The coating can be provided with additional layers of, for example, silicon dioxide to improve the mechanical properties.

Claims

1. A cathode ray tube comprising a display screen having an electroconductive coating which contains poly-3,4-ethylene dioxythiophene, characterized in that the coating has a layer thickness of maximally 100 nm and a sheet resistance of less than 3 kΩ

/□

.

2. A cathode ray tube as claimed in claim 1, characterized in that the coating is covered with an additional layer of silicon dioxide having a thickness of 50-250 nm.

3. A cathode ray tube as claimed in claim 1, characterized in that the coating is successively covered with a first additional layer of titanium dioxide and a second additional layer of silicon dioxide, the coating and the additional layers having a thickness such that the layers jointly exhibit an antireflective effect.

4. A cathode ray tube as claimed in claim 1, characterized in that the coating is successively covered with a first additional layer of silicon dioxide, a second additional layer of titanium dioxide and a third additional layer of silicon dioxide, the coating and the additional layers having a thickness such that the layers jointly exhibit an antireflective effect.

5. A cathode ray tube as claimed in claim 1, characterized in that the coating is covered with an additional layer of a composite of an inorganic network of at least silicon oxide and chains of an organic polymeric component intertwined therewith.

6. A cathode ray tube as claimed in claim 2, characterized in that the additional layer comprises a yellow dye.

7. A cathode ray tube as claimed in claim 5, characterized in that the additional layer comprises a yellow dye.