Keyboard switch with internal fluid containment network

1. An keyboard switch, comprising:

a membrane sheet having an upper surface and a lower surface;

at least one fixed electrode positioned on said upper surface of said membrane sheet;

a protruding member affixed to said upper surface of said membrane sheet, said protruding member being selectively movable;

at least one movable electrode secured inside said protruding member such that when said protruding member is moved toward said membrane sheet, said movable electrode contacting said at least one fixed electrode;

a base plate situated below said membrane sheet such that a gap is formed between said base plate and said membrane sheet;

a support structure secured within said gap and positioned to support said fixed electrode and said protruding member; and

a ventilation opening penetrating said membrane sheet and positioned inside said protruding member in the vicinity of said fixed electrode;

wherein said protruding member and said upper surface of said membrane sheet define a first air space, wherein said lower surface of said membrane sheet, said support structure and said base plate define a second air space, and wherein said first air space is connected to said second air space through said ventilation opening such that all air escaping from said first air space is accommodated within said second air space.

2. The keyboard switch of claim 1 , wherein said protruding member is a flexible cap.

3. The keyboard switch according to claim 2 , wherein said support structure further comprises a substantially circular fixed electrode support surrounded by an annular linking channel, and wherein said ventilation opening can be disposed in a plurality of places around the fixed electrode support.

4. The keyboard switch of claim 3 , wherein said supporting structure further comprises a peripheral support surrounding said substantially circular fixed electrode support, and wherein at least four mutually perpendicular linking channels are formed within said peripheral support such that each of said perpendicular linking channels opens into said annular linking channel.

5. The keyboard switch of claim 3 , wherein said supporting structure further comprises a substantially circular peripheral support surrounding said substantially circular fixed electrode support, and wherein at least four mutually perpendicular linking channels are formed within said peripheral support such that each of said perpendicular linking channels opens into said annular linking channel.

6. The keyboard switch of claim 3 , wherein said supporting structure further comprises a ring-like peripheral support surrounding said substantially circular fixed electrode support, said peripheral support comprising a plurality of linear ribs having a plurality of straight linking channels formed between said linear ribs such that each of said straight linking channels opens into said annular linking channel.

7. The keyboard switch according to claim 2 , wherein said support structure further comprises a peripheral support having an annular linking channel and at least four mutually perpendicular linking channels formed within said peripheral support such that each of said perpendicular linking channels opens into said annular linking channel, and wherein said ventilation opening can be disposed in a plurality of places along said annular linking channel.

8. The keyboard switch of claim 1 , wherein the protruding member is a dome-like projection having an inversion characteristic.

9. The keyboard switch according to claim 8 , wherein said support structure further comprises a substantially circular fixed electrode support surrounded by an annular linking channel, and wherein said ventilation opening can be disposed in a plurality of places around the fixed electrode support.

10. The keyboard switch of claim 9 , wherein said supporting structure further comprises a peripheral support surrounding said substantially circular fixed electrode support, and wherein at least four mutually perpendicular linking channels are formed within said peripheral support such that each of said perpendicular linking channels opens into said annular linking channel.

11. The keyboard switch of claim 9 , wherein said supporting structure further comprises a substantially circular peripheral support surrounding said substantially circular fixed electrode support, and wherein at least four mutually perpendicular linking channels are formed within said peripheral support such that each of said perpendicular linking channels opens into said annular linking channel.

12. The keyboard switch of claim 9 , wherein said supporting structure further comprises a ring-like peripheral support surrounding said substantially circular fixed electrode support, said peripheral support comprising a plurality of linear ribs having a plurality of straight linking channels formed between said linear ribs such that each of said straight linking channels opens into said annular linking channel.

13. The keyboard switch according to claim 8 , wherein said support structure further comprises a peripheral support having an annular linking channel and at least four mutually perpendicular linking channels formed within said peripheral support such that each of said perpendicular linking channels opens into said annular linking channel, and wherein said ventilation opening can be disposed in a plurality of places along said annular linking channel.

14. The keyboard switch of claim 1 , wherein said ventilation opening is connected to said second air space via at least one linking channel formed in said support structure.

15. The keyboard switch according to claim 14 , wherein said support structure further comprises a substantially circular fixed electrode support surrounded by an annular linking channel.

16. The keyboard switch of claim 15 , wherein said ventilation opening can be disposed in a plurality of places around the fixed electrode support.

17. The keyboard switch of claim 15 , wherein said supporting structure further comprises a peripheral support surrounding said substantially circular fixed electrode support, and wherein at least four mutually perpendicular linking channels are formed within said peripheral support such that each of said perpendicular linking channels opens into said annular linking channel.

18. The keyboard switch of claim 15 , wherein said supporting structure further comprises a substantially circular peripheral support surrounding said substantially circular fixed electrode support, and wherein at least four mutually perpendicular linking channels are formed within said peripheral support such that each of said perpendicular linking channels opens into said annular linking channel.

19. The keyboard switch of claim 15 , wherein said supporting structure further comprises a ring-like peripheral support surrounding said substantially circular fixed electrode support, said peripheral support comprising a plurality of linear ribs having a plurality of straight linking channels formed between said linear ribs such that each of said straight linking channels opens into said annular linking channel.

20. The keyboard switch according to claim 14 , wherein said support structure further comprises a peripheral support having an annular linking channel and at least four mutually perpendicular linking channels formed within said peripheral support such that each of said perpendicular linking channels opens into said annular linking channel.