Vehicle accessory microphone

• US 20040208334A1
• Filed: 04/09/2004
• Published: 10/21/2004
• Est. Priority Date: 02/14/2001
• Status: Active Grant

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Watson, Alan R., Bryson, Michael A.
• Granted Patent: US 7,447,320 B2
• Time in Patent Office: Days
• US Class Current: 381/365
• CPC Class Codes: B60R 1/12 Mirror assemblies combined with other articles, e.g. clocks
• CPC Class Codes: B60R 11/0252 for personal computers, e.g. laptops, notebooks
• CPC Class Codes: B60R 2001/1284 with communication systems other than radio-receivers, e.g. keyless entry systems, navigation systems; with anti-collision systems
• CPC Class Codes: B60R 2011/0033 Rear-view mirrors
• CPC Class Codes: H04R 1/083 Special constructions of mouthpieces
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles

Abstract

A vehicle rearview mirror assembly (201) includes one or more microphone assemblies (220a, 220b) positioned on the rear surface (207) of the mirror housing (206). Recesses (248a, 248b) are provided in the rear surface to serve as a deflector for deflecting airflow from the defroster. Front ports (216) are provided on the microphone housing (215) that open upward, while rear ports (218) open downward. The microphone assemblies may include an acoustic dam (230) that extends around the microphone transducer (225) to acoustically separate the acoustic chamber within the microphone housing into two zones such that the front face of the transducer is acoustically coupled to the first zone and the rear face of transducer is acoustically coupled to the second zone. The microphone assemblies may include windscreens (245) made of a material of high acoustic resistivity (i.e., about 1 or more Ω/cm²), and preferably of very high acoustic resistivity (i.e., about 8 or more Ω/cm²).

Claims

1. An interior rearview mirror assembly for a vehicle comprising:

a mirror housing adapted for attachment to the interior of the vehicle, said mirror housing having a back surface generally facing the front of the vehicle and an opening generally facing the rear of the vehicle;

a mirror disposed in said opening of said mirror housing; and

a first microphone transducer carried by said mirror housing along said back surface.

2. The interior rearview mirror assembly of claim 1 and further comprising a second microphone transducer carried by said mirror housing along said back surface at a position laterally spaced apart from said first microphone transducer.

3. The interior rearview mirror assembly of claim 1 and further comprising a first microphone housing mounted on said back surface, wherein said first microphone transducer is mounted within said first microphone housing.

4. The interior rearview mirror assembly of claim 3, wherein said first microphone housing is mounted in a recess formed in said back surface.

5. The interior rearview mirror assembly of claim 4, wherein said recess includes a wall below said first microphone housing such that said back surface deflects airflow coming from the below said rearview mirror assembly and along the windshield of the vehicle away from said first microphone housing.

6. The interior rearview mirror assembly of claim 3, wherein said first microphone housing includes at least one first port acoustically coupled to a front surface of said first microphone transducer.

7. The interior rearview mirror assembly of claim 6, wherein said first microphone housing is mounted on said back surface such that said at least one first port opens generally towards the top of said mirror housing.

8. The interior rearview mirror assembly of claim 6, wherein said first microphone housing comprises a windscreen across said at least one first port.

9. The interior rearview mirror assembly of claim 8, wherein said windscreen is sealed across said at least one first port, said windscreen having hydrophobic properties to prevent water from penetrating said microphone housing through said at least one first port.

10. The interior rearview mirror assembly of claim 8, wherein said windscreen has an acoustic resistivity of at least about 1 acoustic Ω

/cm².

11. The interior rearview mirror assembly of claim 1 and further including a circuit board having a hole sized to receive at least a portion of said first microphone transducer, wherein said first microphone transducer is mounted within the hole in the circuit board such that a portion of said transducer extends below a bottom surface of said circuit board.

12. The interior rearview mirror assembly of claim 11, wherein said circuit board is mounted relative to said rearview mirror assembly such that said circuit board is substantially parallel to a surface of said mirror.

13. The interior rearview mirror assembly of claim 12 and further comprising a mother board mounted in said mirror housing substantially in parallel with said circuit board.

14. The interior rearview mirror assembly of claim 1 further comprising:

a microphone housing defining an acoustic chamber, said microphone housing being mounted to the back surface of said mirror housing, wherein said transducer is contained in the acoustic chamber; and

an acoustic dam extending through said housing and dividing said acoustic chamber into at least two zones including a first zone and a second zone,

wherein said transducer includes a front face exposed to said first zone of said acoustic chamber and a rear face exposed to said second zone of said acoustic chamber.

15. An interior rearview mirror assembly for a vehicle comprising:

a mirror housing adapted for attachment to the interior of the vehicle, said mirror housing having a back surface generally facing the front of the vehicle and an opening generally facing the rear of the vehicle;

a mirror disposed in said opening of said mirror housing;

a first microphone transducer carried by said mirror housing along said back surface; and

a second microphone transducer carried by said mirror housing along said back surface at a position laterally spaced apart from said first microphone transducer.

16. The interior rearview mirror assembly of claim 15 and further comprising:

a first microphone housing mounted on said back surface, wherein said first microphone transducer is mounted within said first microphone housing; and

a second microphone housing mounted on said back surface, wherein said second microphone transducer is mounted within said second microphone housing.

17. The interior rearview mirror assembly of claim 16, wherein said first and second microphone housings are each mounted in a recess formed in said back surface.

18. The interior rearview mirror assembly of claim 17, wherein each said recess includes a wall below a respective one of said first and second microphone housings such that said back surface deflects airflow coming from the below said rearview mirror assembly and along the windshield of the vehicle away from said first and second microphone housings.

19. The interior rearview mirror assembly of claim 16, wherein said first and second microphone housings each include at least one first port acoustically coupled to a front surface of a respective one of said first and second microphone transducers.

20. The interior rearview mirror assembly of claim 19, wherein said first and second microphone housings are mounted on said back surface such that each said at least one first port opens generally towards the top of said mirror housing.

21. The interior rearview mirror assembly of claim 19, wherein said first and second microphone housings comprise a windscreen across said at least one first port.

22. The interior rearview mirror assembly of claim 21, wherein said windscreen is sealed across said at least one first port, said windscreen having hydrophobic properties to prevent water from penetrating said microphone housing through said at least one first port.

23. The interior rearview mirror assembly of claim 21, wherein said windscreen has an acoustic resistivity of at least about 1 acoustic Ω

/cm².

24. The interior rearview mirror assembly of claim 15 and further including a first circuit board and a second circuit board each having a hole sized to receive at least a portion of a corresponding one of said first and second microphone transducers, wherein a corresponding one of said first and second microphone transducers is mounted within each hole in the circuit boards such that a portion of the transducers extends below a bottom surface of the circuit board.

25. The interior rearview mirror assembly of claim 24, wherein each said circuit board is mounted relative to said rearview mirror assembly such that said circuit board is substantially parallel to a surface of said mirror.

26. A microphone assembly comprising:

a microphone housing defining an acoustic chamber;

a circuit board;

a transducer mounted to said circuit board and contained in said acoustic chamber; and

an acoustic dam extending through said housing and dividing said acoustic chamber into at least two zones including at least a first zone and a second zone,

wherein said transducer includes a front face exposed to said first zone of said acoustic chamber and a rear face exposed to said second zone of said acoustic chamber.

27. The microphone assembly of claim 26, wherein said front and rear zones of said acoustic chamber are acoustically coupled within said housing.

28. The microphone assembly of claim 26, wherein said acoustic dam does not extend completely across said acoustic chamber such that said first and second zones of said acoustic chamber are acoustically coupled around at least one end of said acoustic dam.

29. The microphone assembly of claim 26, wherein said acoustic dam is acoustically sealed to said housing proximate said transducer.

30. The microphone assembly of claim 26, wherein said acoustic dam extends the acoustic path length between the front and rear faces of said transducer.

31. The microphone assembly of claim 26, wherein a distance from faces of said transducer to interior walls of said housing is substantially less than a distance between side edges of said transducer and side walls of said housing.

32. The microphone assembly of claim 26 further comprising a second transducer mounted in said microphone housing and having a front face and a rear face, wherein said acoustic chamber is divided into at least three zones including said first and second zones and a third zone.

33. The microphone assembly of claim 32, wherein said front face of said second transducer is exposed to said first zone and said rear face of said second transducer is exposed to said third zone.

34. A method of constructing a microphone assembly, comprising:

providing a microphone transducer having front and rear faces and a peripheral side edge extending around the transducer between the front and rear faces; and

providing an acoustic dam around at least a portion of the peripheral side edge of the transducer to increase the acoustic path length between the front and rear faces of the transducer.

35. The method of claim 34 and further comprising mounting the transducer within a hole in a circuit board such that a central acoustic axis of the transducer is substantially parallel to a surface of the circuit board and such that portions of the transducer extend above and below the circuit board.

36. The method of claim 35, wherein said acoustic dam extends around the side edges of the transducer that extend above the circuit board.