Waterproof sound-permeable membrane, waterproof sound-permeable member, and electronic device

Patent metadata

Field	Value
Publication number	US-10028043-B2
Application number	US-201715655087-A
Country	US
Kind code	B2
Filing date	Jul 20, 2017
Priority date	Nov 24, 2015
Publication date	Jul 17, 2018
Grant date	Jul 17, 2018

Abstract

The waterproof sound-permeable membrane of the present disclosure is a waterproof sound-permeable membrane adapted to permit passage of sound and prevent ingress of water. The air permeability of the waterproof sound-permeable membrane, as expressed by Gurley number, is 20 seconds/100 mL or more. The water entry pressure of the waterproof sound-permeable membrane is 500 kPa or more. When a tensile strength at break of the waterproof sound-permeable membrane in a MD direction is denoted by T1 and a tensile strength at break of the waterproof sound-permeable membrane in a TD direction orthogonal to the MD direction is denoted by T2, a strength ratio (T1/T2) is in a range of 0.5 to 2.0.

First claim

What is claimed is:

1. A waterproof sound-permeable membrane adapted to permit passage of sound and prevent ingress of water, wherein
an air permeability of the waterproof sound-permeable membrane, as expressed by Gurley number, is 20 seconds/100 mL or more,
a water entry pressure of the waterproof sound-permeable membrane is 500 kPa or more,
when a tensile strength at break of the waterproof sound-permeable membrane in a MD direction is denoted by T 1 and a tensile strength at break of the waterproof sound-permeable membrane in a TD direction orthogonal to the MD direction is denoted by T 2 , a strength ratio (T 1 /T 2 ) is in a range of 0.5 to 2.0, and
the waterproof sound-permeable membrane is endurable against a continuous water pressure loading test in which the membrane is continuously exposed to a water pressure of 500 kPa for 10 minutes.

2. The waterproof sound-permeable membrane according to claim 1 , wherein
the waterproof sound-permeable membrane is formed of polytetrafluoroethylene.

3. The waterproof sound-permeable membrane according to claim 2 , wherein
the waterproof sound-permeable membrane is oriented both in the MD direction and in the TD direction.

4. The waterproof sound-permeable membrane according to claim 1 , wherein
the strength ratio (T 1 /T 2 ) is in a range of 0.5 to 1.25.

5. The waterproof sound-permeable membrane according to claim 1 , wherein
at least one selected from the tensile strength T 1 and the tensile strength T 2 is 30 MPa or more.

6. The waterproof sound-permeable membrane according to claim 1 , wherein
the air permeability of the waterproof sound-permeable membrane, as expressed by Gurley number, is 10000 seconds/100 mL or more.

7. The waterproof sound-permeable membrane according to claim 1 , wherein
the air permeability of the waterproof sound-permeable membrane, as expressed by Gurley number, is 20 to 300 seconds/100 mL.

8. The waterproof sound-permeable membrane according to claim 1 , wherein
an insertion loss at 1 kHz measured for the waterproof sound-permeable membrane is 13 dB or less when the waterproof sound-permeable membrane has a circular sound-permeable region with a diameter of 1.5 mm.

9. The waterproof sound-permeable membrane according to claim 1 , wherein
the waterproof sound-permeable membrane has a surface density of 1 to 30 g/m 2 .

10. The waterproof sound-permeable membrane according to claim 1 , wherein
the waterproof sound-permeable membrane has a surface density of 1 to 25 g/m 2 .

11. The waterproof sound-permeable membrane according to claim 1 , wherein
the waterproof sound-permeable membrane is subjected to a coloring treatment.

12. A waterproof sound-permeable member comprising:
the waterproof sound-permeable membrane according to claim 1 ; and
a bonding layer placed on a surface of the waterproof sound-permeable membrane.

13. An electronic device comprising:
a sound transducing part that performs conversion between an electrical signal and sound;
a housing enclosing the sound transducing part and having an opening located between the sound transducing part and the outside of the housing; and
the waterproof sound-permeable membrane according to claim 1 , the waterproof sound-permeable membrane being attached to the housing to cover the opening.

14. An electronic device comprising:
a sound transducing part that performs conversion between an electrical signal and sound;
a housing enclosing the sound transducing part and having an opening located between the sound transducing part and the outside of the housing; and
the waterproof sound-permeable member according to claim 12 , the waterproof sound-permeable member being attached to the housing to cover the opening.

15. The waterproof sound-permeable membrane according to claim 1 , wherein
an amount of change in an insertion loss at 1 kHz of the waterproof sound-permeable membrane during the continuous water pressure loading test is 5.2 dB or less, the insertion loss being a value when the water sound-permeable membrane has a circular sound-permeable region with a diameter of 1.5 mm.

16. The waterproof sound-permeable membrane according to claim 1 , wherein
the strength ratio (T 1 /T 2 ) is in a range of 0.9 to 2.0.

17. The waterproof sound-permeable membrane according to claim 1 , wherein
the strength ratio (T 1 /T 2 ) is in a range of 0.9 to 1.92.

18. The waterproof sound-permeable membrane according to claim 1 , wherein
the air permeability of the waterproof sound-permeable membrane, as expressed by Gurley number, is 68 to 300 seconds/100 mL.

19. The waterproof sound-permeable membrane according to claim 1 , wherein
the water entry pressure of the waterproof sound-permeable membrane is 747 kPa or more, and the thickness of the waterproof sound-permeable membrane is 1 μm to 13 μm.

20. The waterproof sound-permeable membrane according to claim 1 , wherein
the waterproof sound-permeable membrane is subjected to a surface modification treatment for improving a bond strength.

Assignees

• Nitto Denko Corp

Inventors

• Kuki Nobuharu
• Fukushima Tamao

Classifications

• B32B2307/10

  having particular acoustical properties · CPC title

• B32B27/36

  comprising polyesters · CPC title

• B32B27/281

  comprising polyimides · CPC title

• H04R1/44

  Special adaptations for subaqueous use, e.g. for hydrophone · CPC title

• H04R2499/11

  Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's · CPC title