Radio wave absorber and laminate for radio wave absorbers

Patent metadata

Field	Value
Publication number	US-11844201-B2
Application number	US-201917276550-A
Country	US
Kind code	B2
Filing date	Sep 20, 2019
Priority date	Sep 26, 2018
Publication date	Dec 12, 2023
Grant date	Dec 12, 2023

Abstract

A radio wave absorber ( 1 a ) includes a resistive layer ( 20 ), an electrical conductor ( 30 ), and a dielectric layer ( 10 ). The resistive layer ( 20 ) includes indium tin oxide as a main component. The electrical conductor ( 30 ) reflects a radio wave. The dielectric layer ( 10 ) is disposed between the resistive layer ( 20 ) and the electrical conductor ( 30 ) in the thickness direction of the resistive layer ( 20 ). The dielectric layer ( 10 ) is formed of a polymer. The content of tin oxide in the indium tin oxide included in the resistive layer ( 20 ) is more than 0 weight % and less than 20 weight %. The number of hydrogen atoms included in the resistive layer ( 20 ) is 5% or more of the total number of indium atoms, tin atoms, oxygen atoms, and hydrogen atoms included in the resistive layer ( 20 ).

First claim

The invention claimed is:

1. A radio wave absorber comprising:
a resistive layer comprising indium tin oxide as a main component;
an electrical conductor that reflects a radio wave; and
a dielectric layer disposed between the resistive layer and the electrical conductor in the thickness direction of the resistive layer and formed of a polymer, wherein
the content of tin oxide in the indium tin oxide is more than 0 weight % and less than 20 weight %, and
the number of hydrogen atoms comprised in the resistive layer is 5% or more of the total number of indium atoms, tin atoms, oxygen atoms, and hydrogen atoms comprised in the resistive layer.

2. The radio wave absorber according to claim 1 , wherein the resistive layer remains in an amorphous state after the resistive layer is subjected to annealing at 150° C. and for 1 hour.

3. The radio wave absorber according to claim 1 , wherein the resistive layer comprises at least one selected from the group consisting of silicon oxide, magnesium oxide, and zinc oxide.

4. The radio wave absorber according to claim 1 , wherein the electrical conductor comprises indium tin oxide.

5. The radio wave absorber according to claim 1 , wherein the electrical conductor comprises at least one selected from the group consisting of aluminum, copper, an aluminum alloy, and a copper alloy.

6. The radio wave absorber according to claim 1 , wherein the resistive layer has a sheet resistance of 180 to 600 Ω/□.

7. The radio wave absorber according to claim 1 , wherein the resistive layer has a thickness of 18 to 100 nm.

8. The radio wave absorber according to claim 1 , wherein the resistive layer has a Hall mobility of less than 40 cm 2 /(V·s).

9. The radio wave absorber according to claim 1 , wherein the dielectric layer has a relative permittivity of 2.0 to 20.0.

10. The radio wave absorber according to claim 1 , wherein the dielectric layer comprises at least one polymer selected from the group consisting of ethylene-vinyl acetate copolymer, vinyl chloride resin, urethane resin, acrylic resin, acrylic urethane resin, polyethylene, silicone, and polyethylene terephthalate.

11. The radio wave absorber according to claim 1 , further comprising an adhesive layer, wherein
the electrical conductor is disposed between the dielectric layer and the adhesive layer.

12. The radio wave absorber according to claim 1 , further comprising an adhesive layer, wherein
the adhesive layer is disposed between the dielectric layer and the electrical conductor.

13. The radio wave absorber according to claim 1 , wherein the dielectric layer adheres to the electrical conductor.

14. A laminate for radio wave absorbers comprising:
a resistive layer comprising indium tin oxide as a main component; and
a dielectric layer disposed in contact with the resistive layer in the thickness direction of the resistive layer and formed of a polymer, wherein
the content of tin oxide in the indium tin oxide is more than 0 weight % and less than 20 weight %, and
the number of hydrogen atoms comprised in the resistive layer is 5% or more of the total number of indium atoms, tin atoms, oxygen atoms, and hydrogen atoms comprised in the resistive layer.

Assignees

• Nitto Denko Corp

Inventors

• Haishi Motoki
• Yamagata Kazuto
• Machinaga Hironobu

Classifications

• H05K9/0084 Primary

  comprising a single continuous metallic layer on an electrically insulating supporting structure, e.g. metal foil, film, plating coating, electro-deposition, vapour-deposition · CPC title

• B32B27/08

  of synthetic resin · CPC title

• B32B2255/02

  on fibrous or filamentary layer · CPC title

• B32B2255/10

  on synthetic resin layer or on natural or synthetic rubber layer · CPC title

• B32B2307/20

  having particular electrical or magnetic properties, e.g. piezoelectric · CPC title