Microphone unit, close-talking voice input device, information processing system, and method of manufacturing microphone unit

1. A method of manufacturing a microphone unit including a housing which has an inner space, a partition member which is provided in the housing and divides the inner space into a first space and a second space, the partition member being at least partially formed of a diaphragm, and an electrical signal output circuit which outputs an electrical signal based on vibrations of the diaphragm, the method comprising:

forming a first through-hole in the housing through which the first space communicates with an outer space of the housing and forming a second through-hole in the housing through which the second space communicates with the outer space,

wherein a center-to-center distance between the first through-hole and the second through-hole is set within a range in which a sound pressure when using the diaphragm as a differential microphone is equal to or less than a sound pressure when using the diaphragm as a single microphone with respect to sound in a frequency band of 10 kHz or less; and

wherein the diaphragm is disposed closer to either the first through-hole or the second through-hole so that a distance between the diaphragm and the first through-hole is not equal to a distance between the diaphragm and the second through-hole.

2. A method of manufacturing a microphone unit including a housing which has an inner space, a partition member which is provided in the housing and divides the inner space into a first space and a second space, the partition member being at least partially formed of a diaphragm, and an electrical signal output circuit which outputs an electrical signal based on vibrations of the diaphragm, the method comprising:

forming a first through-hole in the housing through which the first space communicates with an outer space of the housing and forming a second through-hole in the housing through which the second space communicates with the outer space in the housing,

wherein a center-to-center distance between the first through-hole and the second through-hole is set within a range in which a sound pressure when using the diaphragm as a differential microphone is equal to or less than a sound pressure when using the diaphragm as a single microphone in all directions with respect to sound in an extraction target frequency; and

wherein the diaphragm is disposed closer to either the first through-hole or the second through-hole so that a distance between the diaphragm and the first through-hole is not equal to a distance between the diaphragm and the second through-hole.

3. A microphone unit comprising:

a housing which has an inner space;

a partition member which is provided in the housing and divides the inner space into a first space and a second space, the partition member being at least partially formed of a diaphragm;

an electrical signal output circuit which outputs an electrical signal based on vibrations of the diaphragm; and

a first through-hole formed in the housing through which the first space communicates with an outer space of the housing and a second through-hole formed in the housing through which the second space communicates with the outer space,

wherein a center-to-center distance between the first through-hole and the second through-hole is set within a range in which a sound pressure when using the diaphragm as a differential microphone is equal to or less than a sound pressure when using the diaphragm as a single microphone with respect to sound in a frequency band of 10 kHz or less; and

wherein the diaphragm is disposed closer to either the first through-hole or the second through-hole so that a distance between the diaphragm and the first through-hole is not equal to a distance between the diaphragm and the second through-hole.

4. The microphone unit as defined in claim 3 ,

wherein the partition member is provided so that a medium that propagates sound waves does not move between the first space and the second space inside the housing.

5. The microphone unit as defined in claim 3 ,

wherein the housing has a polyhedral external shape; and

wherein the first through-hole and the second through-hole are formed in one face of the polyhedron.

6. The microphone unit as defined in claim 5 ,

wherein the diaphragm is disposed so that a normal to the diaphragm is in parallel to the face.

7. The microphone unit as defined in claim 5 ,

wherein the diaphragm is disposed so that a normal to the diaphragm perpendicularly intersects the face.

8. The microphone unit as defined in claim 5 ,

wherein a center-to-center distance between the first through-hole and the second through-hole is 5.2 mm or less.

9. The microphone unit as defined in claim 3 ,

wherein the diaphragm is disposed so that the diaphragm does not overlap the first through-hole or the second through-hole.

10. The microphone unit as defined in claim 3 ,

wherein a center-to-center distance between the first through-hole and the second through-hole is 5.2 mm or less.

11. The microphone unit as defined in claim 3 ,

wherein the electrical signal output circuit is at least partially formed in the housing.

12. The microphone unit as defined in claim 3 ,

wherein the housing has a shielding structure which electromagnetically separates the inner space and the outer space of the housing.

13. The microphone unit as defined in claim 3 ,

wherein the diaphragm includes a vibrator having an SN ratio of about 60 dB or more.

14. A close-talking voice input device comprising the microphone unit as defined in claim 3 .

15. The voice input device as defined in claim 14 ,

wherein the housing has a polyhedral external shape; and

wherein the first through-hole and the second through-hole are formed in one face of the polyhedron.

16. The voice input device as defined in claim 14 ,

wherein a center-to-center distance between the first through-hole and the second through-hole is 5.2 mm or less.

17. The voice input device as defined in claim 14 ,

wherein the diaphragm includes a vibrator having an SN ratio of about 60 dB or more.

18. The voice input device as defined in claim 14 ,

wherein the microphone unit is provided in the housing of a voice input device so that the first and second through-holes are disposed at different positions along a travel direction of a user's voice which is limited by a position of the housing in the voice input device.

19. The microphone unit as defined in claim 3 ,

wherein the microphone unit is provided in the housing of a voice input device so that the first and second through-holes are disposed at different positions along a travel direction of a user's voice which is limited by a position of the housing in the voice input device.

20. The microphone unit as defined in claim 3 ,

wherein a center-to-center distance between the first through-hole and the second through-hole is set so that a phase component intensity ratio of a user's voice is smaller than an amplitude component intensity ratio.

21. The microphone unit as defined in claim 3 ,

wherein a center-to-center distance between the first through-hole and the second through-hole is set so that a phase component intensity ratio of a noise is 0 dB or less.

22. A microphone unit comprising:

a housing which has an inner space;

a partition member which is provided in the housing and divides the inner space into a first space and a second space, the partition member being at least partially formed of a diaphragm;

an electrical signal output circuit which outputs an electrical signal based on vibrations of the diaphragm; and

a first through-hole formed in the housing through which the first space communicates with an outer space of the housing and a second through-hole formed in the housing through which the second space communicates with the outer space,

wherein a center-to-center distance between the first through-hole and the second through-hole is set within a range in which a sound pressure when using the diaphragm as a differential microphone is equal to or less than a sound pressure when using the diaphragm as a single microphone in all directions with respect to sound in an extraction target frequency band; and

wherein the diaphragm is disposed closer to either the first through-hole or the second through-hole so that a distance between the diaphragm and the first through-hole is not equal to a distance between the diaphragm and the second through-hole.

23. The microphone unit as defined in claim 22 ,

wherein the partition member is provided so that a medium that propagates sound waves does not move between the first space and the second space inside the housing.

24. The microphone unit as defined in claim 22 ,

wherein the housing has a polyhedral external shape; and

wherein the first through-hole and the second through-hole are formed in one face of the polyhedron.

25. The microphone unit as defined in claim 24 ,

wherein the diaphragm is disposed so that a normal to the diaphragm is in parallel to the face.

26. The microphone unit as defined in claim 24 ,

wherein the diaphragm is disposed so that a normal to the diaphragm perpendicularly intersects the face.

27. The microphone unit as defined in claim 24 ,

wherein a center-to-center distance between the first through-hole and the second through-hole is 5.2 mm or less.

28. The microphone unit as defined in claim 22 ,

wherein the diaphragm is disposed so that the diaphragm does not overlap the first through-hole or the second through-hole.

29. The microphone unit as defined in claim 22 ,

wherein a center-to-center distance between the first through-hole and the second through-hole is 5.2 mm or less.

30. The microphone unit as defined in claim 22 ,

wherein the electrical signal output circuit is at least partially formed in the housing.

31. The microphone unit as defined in claim 22 ,

wherein the housing has a shielding structure which electromagnetically separates the inner space and the outer space of the housing.

32. The microphone unit as defined in claim 22 ,

wherein the diaphragm includes a vibrator having an SN ratio of about 60 dB or more.

33. A close-talking voice input device comprising the microphone unit as defined in claim 22 .

34. The voice input device as defined in claim 33 ,

wherein the housing has a polyhedral external shape; and

wherein the first through-hole and the second through-hole are formed in one face of the polyhedron.

35. The voice input device as defined in claim 33 ,

wherein a center-to-center distance between the first through-hole and the second through-hole is 5.2 mm or less.

36. The voice input device as defined in claim 33 ,

wherein the diaphragm includes a vibrator having an SN ratio of about 60 dB or more.

37. The voice input device as defined in claim 33 ,

wherein the microphone unit is provided in the housing of a voice input device so that the first and second through-holes are disposed at different positions along a travel direction of a user's voice which is limited by a position of the housing in the voice input device.

38. The microphone unit as defined in claim 22 ,

wherein the microphone unit is provided in the housing of a voice input device so that the first and second through-holes are disposed at different positions along a travel direction of a user's voice which is limited by a position of the housing in the voice input device.

39. The microphone unit as defined in claim 22 ,

wherein a center-to-center distance between the first through-hole and the second through-hole is set so that a phase component intensity ratio of a user's voice is smaller than an amplitude component intensity ratio.

40. The microphone unit as defined in claim 22 ,

wherein a center-to-center distance between the first through-hole and the second through-hole is set so that a phase component intensity ratio of a noise is 0 dB or less.