Pressure-sensitive sensor

1. A pressure-sensitive sensor comprising:

a cantilever;

a frame which is provided around the cantilever and holds a base end of the cantilever;

a gap formed between the cantilever and the frame; and

a liquid which seals the gap.

2. The pressure-sensitive sensor according to claim 1 , wherein

the gap is held in a state of being sealed by the liquid, regardless of a deformation of the cantilever.

3. The pressure-sensitive sensor according to claim 1 , wherein

a liquid retaining region which includes a surface of the cantilever and the gap, and a liquid expelling region which is formed around the liquid retaining region are provided.

4. The pressure-sensitive sensor according to claim 1 , wherein

a gas chamber which is connected to the gap is provided in a rear face side of the cantilever.

5. The pressure-sensitive sensor according to claim 4 , wherein

a film having flexibility is provided so as to cover the liquid, and outside pressure is transmitted to the liquid through the film.

6. The pressure-sensitive sensor according to claim 4 , wherein

the liquid is provided locally with respect to the gap, and the outside pressure is transmitted directly to the cantilever.

7. The pressure-sensitive sensor according to claim 4 , further comprising a protection mechanism which limits the deformation of the cantilever within a fixed range and thereby protects the cantilever.

8. The pressure-sensitive sensor according to claim 1 , wherein

a temperature compensation system for compensating temperature characteristics of the cantilever is provided.

9. The pressure-sensitive sensor according to claim 8 , wherein

the temperature compensation system has a non-deforming type dummy cantilever that has characteristics similar to resistance variation characteristics with respect to temperature, which the cantilever has.

10. The pressure-sensitive sensor according to claim 4 , wherein

the pressure-sensitive sensor is arranged in a liquid tank and detects a pressure which travels in the liquid in the liquid tank.

11. The pressure-sensitive sensor according to claim 10 , wherein

the pressure-sensitive sensor is a hydrophone which detects a sound wave that travels in the liquid.

12. The pressure-sensitive sensor according to claim 11 , wherein

the hydrophone has a sound guide which guides the sound wave to the cantilever.

13. A sensor array, wherein

the pressure-sensitive sensors according to claim 1 are arrayed one-dimensionally or two-dimensionally.

14. The pressure-sensitive sensor according to claim 1 , wherein

the liquid has an adsorbing molecule which adsorbs a gas component to be detected, on a liquid surface.

15. The pressure-sensitive sensor according to claim 14 , further comprising:

a gas chamber which is formed in a rear face side of the cantilever so that gas can flow through the gap;

a through hole which connects the inside of the gas chamber and the outside; and

a filter which is provided in the through hole and through which gases except the gas component to be detected can pass.

16. A method of using a pressure-sensitive sensor, in which the pressure-sensitive sensor includes:

a cantilever;

a frame which is provided around the cantilever and holds a base end of the cantilever; and a gap formed between the cantilever and the frame, the method comprising:

a step of sealing the gap by a liquid so that an interface of the liquid in the gap stays inside or in a vicinity of the gap, regardless of a deformation of the cantilever, and thereby maintaining a sealed state of the gap; and

a step of detecting the deformation of the cantilever, which occurs due to a force exerted from the outside, in the sealed state, as a change of electrical characteristics that the cantilever has.