Black liquid-crystal polymer film and multilayer board

Patent metadata

Field	Value
Publication number	US-11365353-B2
Application number	US-201916431908-A
Country	US
Kind code	B2
Filing date	Jun 5, 2019
Priority date	Dec 5, 2016
Publication date	Jun 21, 2022
Grant date	Jun 21, 2022

Abstract

A black liquid-crystal polymer film that contains a black pigment and a liquid crystal polymer and the black liquid-crystal polymer film has a lightness of 45 or less, a dielectric loss tangent of 0.0035 or less, a minimum dielectric breakdown strength of 60 kV/mm or more, and a maximum-to-minimum ratio of in-plane thermal linear expansion coefficient in the range of 1.0 to 2.5.

First claim

The invention claimed is:

1. A black liquid-crystal polymer film comprising:
a black pigment; and
a liquid crystal polymer, wherein
an average primary particle size of the black pigment is 15 to 75 nm,
an amount of the black pigment is 0.1% to 5.0% by mass of the liquid crystal polymer,
the black liquid-crystal polymer film having a thickness of 10 μm to 75 μm, a lightness of 45 or less, a dielectric loss tangent of 0.0035 or less, a minimum dielectric breakdown strength of 60 kV/mm or more, and a maximum-to-minimum ratio of in-plane thermal linear expansion coefficient in the range of 1.0 to 2.5, and
wherein a high-concentration spot of the black pigment has a size of 9/10 or less of a film thickness of the black liquid-crystal polymer film.

2. The black liquid-crystal polymer film according to claim 1 , wherein the black liquid-crystal polymer film has a relative permittivity of 3.5 or less.

3. The black liquid-crystal polymer film according to claim 1 , wherein the black liquid-crystal polymer film has a thermal linear expansion coefficient in a range of 3 to 30 ppm/° C.

4. The black liquid-crystal polymer film according to claim 1 , wherein the black liquid-crystal polymer film is a long film.

5. A laminated sheet comprising:
the black liquid-crystal polymer film according to claim 1 ; and
a metal foil on one or both faces of the black liquid-crystal polymer film.

6. An electronic circuit board comprising a circuit on the metal foil of the laminated sheet according to claim 5 .

7. A multilayer board comprising two or more of the electronic circuit boards according to claim 6 .

8. The multilayer board according to claim 7 , further comprising an electronic device mounted on the circuit.

9. An electronic component comprising:
a mother board; and
the multilayer board according to claim 8 mounted on the mother board.

10. A black liquid-crystal polymer film comprising:
a black pigment; and
a liquid crystal polymer, wherein
an average primary particle size of the black pigment is 15 to 75 nm,
an amount of the black pigment is 0.1% to 5.0% by mass of the liquid crystal polymer,
a thickness of the black liquid-crystal polymer film is 10 μm to 75 μm, and
a number density of high-concentration spots of the black pigment with a size in the range of 3/10 to 9/10 of a film thickness of the black liquid-crystal polymer film is 15/342 mm 2 or less.

11. The black liquid-crystal polymer film according to claim 10 , wherein the black liquid-crystal polymer film has a relative permittivity of 3.5 or less.

12. The black liquid-crystal polymer film according to claim 10 , wherein the black liquid-crystal polymer film has a thermal linear expansion coefficient in a range of 3 to 30 ppm/° C.

13. The black liquid-crystal polymer film according to claim 10 , wherein the black liquid-crystal polymer film is a long film.

14. A laminated sheet comprising:
the black liquid-crystal polymer film according to claim 10 ; and
a metal foil on one or both faces of the black liquid-crystal polymer film.

15. An electronic circuit board comprising a circuit on the metal foil of the laminated sheet according to claim 14 .

16. A multilayer board comprising two or more of the electronic circuit boards according to claim 15 .

17. The multilayer board according to claim 16 , wherein in a side view, in the black liquid-crystal polymer film, the high-concentration spot of the black pigment between the two circuits disposed on both faces of the black liquid-crystal polymer film has a size of 9/10 or less of the shortest distance between the circuits.

18. The multilayer board according to claim 16 , wherein in a top view a high-concentration spot of the black pigment disposed between the two circuits disposed on one face of the black liquid-crystal polymer film has a size of 9/10 or less of the shortest distance between the circuits.

19. The multilayer board according to claim 16 , wherein in a side view a high-concentration spot of the black pigment disposed directly above and/or directly under the circuit has a size of ½ or less of the minimum width of the circuit.

20. The multilayer board according to claim 16 , further comprising an electronic device mounted on the circuit.

21. An electronic component comprising:
a mother board; and
the multilayer board according to claim 16 mounted on the mother board.

Assignees

• Murata Manufacturing Co

Inventors

• Nishi Yoshimasa
• Fukutake Sunao
• Moriya Akira
• Iida Kanto

Classifications

• C09K19/3809 Primary

  Polyesters; Polyester derivatives, e.g. polyamides · CPC title

• C08J5/18

  Manufacture of films or sheets · CPC title

• C09K2219/03

  in the form of films, e.g. films after polymerisation of LC precursor · CPC title

• H05K2201/0141

  Liquid crystal polymer [LCP] · CPC title

• H05K2201/0191

  wherein the thickness of the dielectric plays an important role · CPC title