Flexible wiring circuit board and imaging device

1. A flexible wiring circuit board having flexibility comprising:

a first insulating layer,

a wire disposed at one side in a thickness direction of the first insulating layer,

a second insulating layer disposed at one side in the thickness direction of the wire,

a shield layer disposed at one side in the thickness direction of the second insulating layer, and

a third insulating layer disposed at one side in the thickness direction of the shield layer,

wherein

the shield layer includes

an electrically conductive layer and

two barrier layers sandwiching the electrically conductive layer therebetween in the thickness direction;

the electrically conductive layer is selected from a metal belonging to a group 11, and the fourth period and the fifth period in the periodic table;

each of the two barrier layers is selected from a metal belonging to groups 4 to 10, and the fourth to the sixth periods in the periodic table;

each of the materials for the second insulating layer and the third insulating layer is a polyimide;

the electrically conductive layer has a thickness of 0.05 μm or more and 1.0 μm or less; and

each of the two barrier layers has a thickness of 0.01 μm or more and 0.05 μm or less.

2. The flexible wiring circuit board according to claim 1 , wherein

each of the two barrier layers is one metal selected from the group consisting of titanium, chromium, nickel, palladium, and tantalum.

3. The flexible wiring circuit board according to claim 1 , wherein

the wire includes a ground wire, and

the shield layer is electrically connected to the ground wire by bringing one of the two barrier layers into contact with the ground wire.

4. The flexible wiring circuit board according to claim 1 , wherein

the wire is in direct contact with the first insulating layer,

the second insulating layer is in direct contact with the wire,

one of the two barrier layers that is positioned at the other side in the thickness direction with respect to the electrically conductive layer is in direct contact with the second insulating layer,

the electrically conductive layer is in direct contact with the barrier layer that is positioned at the other side in the thickness direction with respect to the electrically conductive layer,

another of the two barrier layers that is positioned at one side in the thickness direction with respect to the electrically conductive layer is in direct contact with the electrically conductive layer, and

the third insulating layer is in direct contact with the other of the two barrier layers that is positioned at one side in the thickness direction with respect to the electrically conductive layer.

5. The flexible wiring circuit board according to claim 1 further comprising:

a fourth insulating layer and a second wire disposed between the wire and the second insulating layer in the thickness direction, wherein

the fourth insulating layer is disposed at one side in the thickness direction of the wire and

the second wire is disposed at one side in the thickness direction of the fourth insulating layer.

6. The flexible wiring circuit board according to claim 1 comprising an imaging element-mounting board for mounting an imaging element.

7. An imaging device comprising:

the flexible wiring circuit board according to claim 1 and

an imaging element mounted on the flexible wiring circuit board.

8. The flexible wiring circuit board according to claim 1 , wherein each of the second insulating layer and the third insulating layer has a thickness in a range of 1 μm or more and 5 μm or less.

9. The flexible wiring circuit board according to claim 1 , wherein the material for the first insulating layer is a polyimide.

10. The flexible wiring circuit board according to claim 1 , wherein the first insulating layer has a thickness in a range of 1 μm or more and 8 μm or less.