Electronic device with improved shielding structure

1 . An electronic device comprising:

a circuit board having a first surface and a second surface;

a first member for covering the first surface to function as a shield of the circuit board; and

a second member placed on a side of the second surface, wherein:

the first member has a first encompassing region surrounding an electronic component mounted on the first surface,

the first encompassing region has, in at least a portion thereof, a first outer region located on an outer side of an outer edge of the circuit board,

the second member has a second outer region located on the outer side of the outer edge of the circuit board,

the second outer region has:

a first outer fixed portion and a second outer fixed portion fixed to the first outer region, and

at least two projections located between the first outer fixed portion and the second outer fixed portion in a direction along the outer edge of the circuit board that protrude from a surrounding surface of second outer region,

the first member and the second member are in contact with each other at the first outer fixed portion and the second outer fixed portion by fasteners, and

the first member warps upwards away from the surrounding surface of the second outer region at a region where the first member contacts the at least two projections thereby forming a gap between the first member and the second member in a space between the at least two projections.

2 . The electronic device according to claim 1 ,

wherein the second member is a member for covering the second surface to function as a shield of the circuit board and has a second encompassing region surrounding an electronic component mounted on the second surface, and

the second encompassing region has, in at least a portion thereof, the second outer region.

3 . The electronic device according to claim 1 , wherein the first encompassing region has a first inner region in contact with a ground pattern formed on the first surface of the circuit board.

4 . The electronic device according to claim 3 , wherein the first inner region has

at least one inner fixed portion fixed to the circuit board, and

at least one inner contact portion being located away from the at least one inner fixed portion in an extending direction of the first encompassing region and being in contact with the ground pattern.

5 . The electronic device according to claim 4 ,

wherein the first outer fixed portion, the second outer fixed portion, and the at least two projections form contact points between the first member and the second member across the outer edge of the circuit board,

the at least one inner fixed portion and the at least one inner contact portion form contact points between the first member and the ground pattern, and

a distance between two of the contact points adjacent to each other across the outer edge of the circuit board is less than a third of a wavelength of noise that the first member shields.

6 . The electronic device according to claim 4 ,

wherein the first outer fixed portion, the second outer fixed portion, and the at least two projections form contact points between the first member and the second member across the outer edge of the circuit board,

the at least one inner fixed portion and the at least one inner contact portion form contact points between the first member and the ground pattern, and

a distance between two of the contact points adjacent to each other across the outer edge of the circuit board is 20 mm or less.

7 . The electronic device according to claim 1 , wherein the at least two projections are formed by sheet metal processing.

8 . The electronic device according to claim 1 ,

wherein the second outer region further has an additional projection that protrudes from the surrounding surface of the second outer region, is located in the direction along the outer edge of the circuit board, and is separated from the at least two projections by either the first outer fixed portion or the second outer fixed portion.

9 . The electronic device according to claim 1 ,

wherein the at least two projections include only two projections separating the first outer fixed portion from the second outer fixed portion in the direction along the outer edge of the circuit board.

10 . The electronic device according to claim 1 , wherein a distance between the first outer fixed portion and at least one of the at least two projections is less than a third of a wavelength of noise that the first member shields.

11 . The electronic device according to claim 1 , wherein a distance between the first outer fixed portion and at least one of the at least two projections is 20 mm or less.

12 . The electronic device according to claim 4 , wherein:

the second outer region further has a plurality of outer fixed portions and a plurality of projections that protrude from the surrounding surface of the second outer region,

the plurality of outer fixed portions comprises the first outer fixed portion and the second outer fixed portion,

the plurality of projections comprises the at least two projections located between the first outer fixed portion and the second outer fixed portion,

two or less of the plurality of projections are formed between adjacent two of the plurality of outer fixed portions,

the first inner region has a plurality of inner fixed portions as the at least one inner fixed portion,

two or less of the inner contact portions are formed between adjacent two of the inner fixed portions as the at least one inner contact portion,

the plurality of outer fixed portions and the plurality of projections from contact points between the first member and the second member,

a plurality of the inner fixed portions and the two or less inner contact portions form contact points between the first member and the ground pattern, and

a distance between every adjacent two of the contact points is:

less than a third of a wavelength of noise that one of the first member and the second member shields, or

less than or equal to 20 mm.

13 . The electronic device according to claim 2 , wherein

the first encompassing region has a first inner region in contact with a ground pattern formed on the first surface of the circuit board, and

the second encompassing region has a second inner region in contact with a second ground pattern formed on the second surface of the circuit board.

14 . The electronic device according to claim 13 , wherein

the first inner region has at least one first inner fixed portion fixed to the circuit board with a fixture, and

at least one first contact portion being located away from the at least one first inner fixed portion in an extending direction of the first encompassing region and being in contact with the ground pattern via a projection, and

the second inner region has

at least one second inner fixed portion fixed to the circuit board with the fixture, and

at least one second contact portion being located away from the at least one second inner fixed portion in an extending direction of the second encompassing region and being in contact with the ground pattern via a projection.

15 . The electronic device according to claim 1 , wherein the fasteners comprise screws.

16 . The electronic device according to claim 1 , wherein the first member comprises a first material having a first rigidity, wherein the second member comprises a second material having a second rigidity, wherein the first rigidity is less than the second rigidity.