Vehicle accessory microphone

• US 7,443,988 B2
• Filed: 10/09/2006
• Issued: 10/28/2008
• Est. Priority Date: 11/19/1999
• Status: Expired due to Fees

• Current Assignee: Gentex Corporation
• Original Assignee: Gentex Corporation
• Inventors: Watson, Alan R., Turnbull, Robert R., Knapp, Robert C., Poe, G. Bruce
• Primary Examiner(s): Mei; Xu
• Application Number:
  US11/539,751
• Publication Number:
  US 20070133827A1
• Time in Patent Office: 750 Days
• Field of Search: 381/86, 381/92, 381/91, 381/122, 381355-357, 381/95, 381111-113
• US Class Current: 381/86
• CPC Class Codes: B60R 11/0247 for microphones or earphones
• 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: H04R 1/08 Mouthpieces; Microphones; Attachments therefor
• CPC Class Codes: H04R 1/342 for microphones
• CPC Class Codes: H04R 1/38 in which sound waves act upon both sides of a diaphragm and incorporating acoustic phase-shifting means, e.g. pressure-gradient microphone
• CPC Class Codes: H04R 1/406 microphones
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 3/005 for combining the signals of two or more microphones specially adapted for hearing aids H04R25/407

Abstract

A microphone includes one or more transducers positioned in a housing. Circuitry is coupled to the transducer for outputting an electrical signal such that the microphone has a main lobe directed forwardly and attenuates signals originating from the sides. The microphone transducers can advantageously include multiple transducers, which with the circuit produce a desired sensitivity pattern. The microphone can be employed in a vehicle accessory.

Claims

1. A vehicle accessory, comprising:

a housing;

a mirror element;

at least one first transducer positioned in the housing;

at least one second transducer positioned in the housing, wherein the first and second transducers are positioned in spaced relation inside the housing;

a circuit coupled to the first and second transducers for combining the output signal of the first and second transducers to produce a combined audio signal;

a high pass filter for filtering the combined audio signal to produce an enhanced audio signal with a reduced noise component; and

wherein a signal entering the second transducer is electronically delayed using a time delay circuit by an amount equal to the time period required for sound to travel a predetermined distance between the first transducer and the second transducer.

2. A vehicle accessory as in claim 1, wherein the reduced noise component is substantially devoid of frequency audio components below a predetermined frequency.

3. A vehicle accessory as in claim 1, wherein the predetermined frequency is below components of a human voice required for intelligibility.

4. A vehicle accessory as in claim 1, further comprising an amplifier amplifying audio from the at least one first transducer and the at least one second transducer before it is filtered by the high pass filter.

5. A vehicle accessory as in claim 4, wherein the amplifier is operated as a unity gain follower.

6. A vehicle accessory as in claim 1, wherein the high pass filter is a 3-pole filter.

7. A vehicle accessory as in claim 6, wherein the high pass filter has a cutoff frequency in a range between 100-300 Hz.

8. A vehicle accessory as in claim 1, wherein the vehicle accessory is a rearview mirror.

9. A vehicle accessory as in claim 1, wherein the housing includes at least one port for directing audio to the at least one first transducer and the at least one second transducer.

10. A vehicle accessory as in claim 1, wherein the at least one first transducer and the at least one second transducer are at least one from the group of capacitor, electret, piezo electric, or carbon transducers.

11. A vehicle rearview mirror accessory, comprising:

a mirror element;

a housing including at least one microphone port;

at least one first transducer positioned in the housing;

at least one second transducer positioned in the housing, wherein the first and second transducers are positioned in spaced relation inside the housing;

a circuit for combining the output signal of the first and second transducers;

a filter for producing an audio signal with a reduced noise component below a predetermined frequency; and

wherein a signal entering the at least one second transducer is electronically delayed using a time delay circuit by an amount equal to the time period required for sound to travel a predetermined distance between the at least one first transducer and the at least one second transducer.

12. A vehicle rearview mirror accessory as in claim 11, wherein the predetermined frequency is below that of a human voice.

13. A vehicle rearview mirror accessory as in claim 11, wherein the amplifier is operated as a unity gain follower.

14. A vehicle rearview mirror accessory as in claim 11, wherein the filter is a 3-pole high pass filter.

15. A vehicle rearview mirror accessory as in claim 14, wherein the high pass filter has a cutoff frequency in a range between 100-300 Hz.

16. A vehicle rearview mirror accessory as in claim 11, wherein the housing includes at least one port for directing audio to the at least one first transducer and the at least one second transducer.

17. A vehicle rearview mirror accessory as in claim 11, wherein the at least one first transducer and the at least one second transducer are at least one from the group of capacitor, electret, piezo electric or carbon transducers.

18. A vehicle rearview mirror accessory, comprising:

a mirror element;

at least one first transducer positioned in the housing;

at least one second transducer positioned in the housing, wherein the first and second transducers are positioned in spaced relation inside the housing;

a housing having at least one audio port for directing audio to the at lest one first transducer and the at least one second transducer;

an amplifier circuit for combining the output signal of the first and second transducers;

a high pass filter for providing an audio signal with a reduced noise component below that of the human voice; and

wherein a signal entering the at least one second transducer is electronically delayed using a time delay circuit by an amount equal to the time period required for sound to travel a predetermined distance between the at least one first transducer and the at least one second transducer.