Light transmitting electromagnetic wave filter and process for producing the same

• US 6,579,423 B2
• Filed: 12/11/2001
• Issued: 06/17/2003
• Est. Priority Date: 04/06/1999
• Status: Expired due to Fees

• Current Assignee: Nippon Sheet Glass Company Limited
• Original Assignee: Nippon Sheet Glass Company Limited
• Inventors: Anzaki, Toshiaki, Ogino, Etsuo
• Primary Examiner(s): Jones, Deborah
• Assistant Examiner(s): Piziali, Andrew
• Application Number:
  US10/011,765
• Publication Number:
  US 20020086164A1
• Time in Patent Office: 553 Days
• Field of Search: 204/192.12, 204/192.15, 204/192.22, 204/298.06, 204/298.12, 204/298.14, 204/298.26, 204/192.16, 204/192.23, 427/164, 427/165, 428/673, 428/432, 428/446, 428/448, 428/469, 428/472, 428/697, 428/698, 428/699, 428/701, 428/702, 428/704
• US Class Current: 204/192.15
• CPC Class Codes: B32B 17/10174 Coatings of a metallic or dielectric material on a constituent layer of glass or polymer
• CPC Class Codes: C03C 17/36 at least one coating being a metal
• CPC Class Codes: C03C 17/3613 Coatings of type glass/inorganic compound/metal/inorganic compound/metal/other
• CPC Class Codes: C03C 17/3639 Multilayers containing at least two functional metal layers
• CPC Class Codes: C03C 17/3644 the metal being silver
• CPC Class Codes: C03C 17/3676 specially adapted for use as electromagnetic shield
• CPC Class Codes: C03C 2217/78 Coatings specially designed to be durable, e.g. scratch-resistant
• CPC Class Codes: C23C 14/08 Oxides C23C14/10 takes precedence
• CPC Class Codes: C23C 14/3414 Metallurgical or chemical aspects of target preparation, e.g. casting, powder metallurgy
• CPC Class Codes: G02B 5/285 comprising deposited thin solid films G02B5/281 - G02B5/289 take precedence; multilayered film filters for fibre optic multiplexing G02B6/29361
• CPC Class Codes: G02B 5/287 comprising at least one layer of organic material
• CPC Class Codes: H01J 2211/446 Electromagnetic shielding means; Antistatic means
• CPC Class Codes: H05K 9/0096 for television displays, e.g. plasma display panel

Abstract

A light transmitting electromagnetic wave filter comprising a transparent and a light transmitting electromagnetic wave shield film having a laminate structure composed of 2n+1 (n≧1) layers in which at least two dielectric layers and at least one silver layer are alternately laminated, with each other with the dielectric layer being the first to be provided on the transparent substrate, wherein at least one of the dielectric layers is an antistatic metal oxide layer having a refractive index of 1.6 to 2.7 at a wavelength of 550 nm, which is preferably formed by sputtering using a metal oxide, e.g., tin-containing indium oxide, as a target in an atmosphere having a reduced oxygen content. The electromagnetic wave filter has a high visible light transmission and a low near infrared transmission, is free from pin holes or contamination, and exhibits high durability against moist heat, etc.

Claims

1. A process for producing a light-transmitting electromagnetic wave filter comprising a transparent substrate having on one side thereof a light-transmitting electromagnetic wave shield film comprising 2n+1 (n≧

1) layers in which at least two dielectric layers comprising an antistatic metal oxide layer and at least one silver layer are alternately laminated with each other with the dielectric layer being the first to be provided on the transparent substrate,

wherein said silver layer is formed by sputtering using silver as a target, and said antistatic metal oxide layer is formed by sputtering using, as a target, a metal oxide whose sheet resistance is 50 Ω

/or less,

and further wherein (i) a barrier layer is provided as an intermediate layer of a metal oxide layer, or (ii) a barrier layer is provided as an intermediate layer of a metal oxide layer and a barrier layer is provided on an outer side of a metal oxide layer constituting an outermost dielectric layer.

2. The process for producing a light transmitting electromagnetic wave filter as claimed in claim 1, wherein the sputtering for forming the antistatic metal oxide layer is carried out in such a manner that a sintered body of a metal oxide powder is set on a pair of adjacent magnetron cathodes, and a negative voltage is applied to each cathode while alternately reversing the polarities of the targets at a frequency of 10 Hz to 1 MHz to generate glow discharge plasma thereby to sputter the target.

3. The process for producing a light-transmitting electromagnetic wave filter as claimed in claim 1, wherein the barrier layer is one of silicon nitride and silicon oxynitride.

4. The process for producing a light-transmitting electromagnetic wave filter as claimed in claim 1, wherein the outermost dielectric layer is a laminate comprising an antistatic metal oxide layer and a barrier layer.