Panel-form microphones

• US 6,307,942 B1
• Filed: 10/22/1998
• Issued: 10/23/2001
• Est. Priority Date: 09/02/1995
• Status: Expired due to Fees

• Current Assignee: New Transducers Limited (Alphabet Inc.)
• Original Assignee: New Transducers Limited (Alphabet Inc.)
• Inventors: Harris, Neil John, Colloms, Martin, Azima, Henry
• Primary Examiner(s): LE, HUYEN D
• Application Number:
  US09/011,772
• Time in Patent Office: 1,097 Days
• Field of Search: 381/152, 381/354, 381/355, 381/361, 381/365, 381/173, 381/190, 381/398, 381/396, 381/FOR.146, 381/423, 381/425, 381/431
• US Class Current: 381/152
• CPC Class Codes: B42D 15/022 combined with permanently fastened sound-producing or light-emitting means or carrying sound records
• CPC Class Codes: B60R 11/0217 for loud-speakers
• CPC Class Codes: G06F 1/1605 Multimedia displays, e.g. with integrated or attached speakers, cameras, microphones
• CPC Class Codes: G06F 1/1616 with folding flat displays, e.g. laptop computers or notebooks having a clamshell configuration, with body parts pivoting to an open position around an axis parallel to the plane they define in closed position
• CPC Class Codes: G06F 1/1688 the I/O peripheral being integrated loudspeakers
• CPC Class Codes: G06F 9/02 using wired connections, e.g. plugboards
• CPC Class Codes: G07F 9/02 Devices for alarm or indication, e.g. when empty; Advertising arrangements in coin-freed apparatus alarms or warning devices indicating the interruption of flow to be metered G07F15/10
• CPC Class Codes: H04R 1/021 incorporating only one transducer
• CPC Class Codes: H04R 1/025 Arrangements for fixing loudspeaker transducers, e.g. in a box, furniture
• CPC Class Codes: H04R 1/028 associated with devices performing functions other than acoustics, e.g. electric candles
• CPC Class Codes: H04R 1/24 Structural combinations of separate transducers or of two parts of the same transducer and responsive respectively to two or more frequency ranges
• CPC Class Codes: H04R 1/26 Spatial arrangements of separate transducers responsive to two or more frequency ranges
• CPC Class Codes: H04R 1/2811 for loudspeaker transducers
• CPC Class Codes: H04R 17/00 Piezoelectric transducers; Electrostrictive transducers piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners H10N30/00
• CPC Class Codes: H04R 2201/021 Transducers or their casings adapted for mounting in or to a wall or ceiling
• CPC Class Codes: H04R 2307/029 Diaphragms comprising fibres
• CPC Class Codes: H04R 2440/07 Loudspeakers using bending wave resonance and pistonic motion to generate sound
• CPC Class Codes: H04R 2499/13 Acoustic transducers and sound field adaptation in vehicles
• CPC Class Codes: H04R 2499/15 Transducers incorporated in visual displaying devices, e.g. televisions, computer displays, laptops
• CPC Class Codes: H04R 3/04 for correcting frequency response
• CPC Class Codes: H04R 5/02 : Spatial or constructional arrangements of loudspeakers
• CPC Class Codes: H04R 5/027 : Spatial or constructional arrangements of microphones, e.g. in dummy heads
• CPC Class Codes: H04R 7/045 : using the distributed mode principle, i.e. whereby the acoustic radiation is emanated from uniformly distributed free bending wave vibration induced in a stiff panel and not from pistonic motion
• CPC Class Codes: H04R 7/06 : comprising a plurality of sections or layers
• CPC Class Codes: H04R 7/08 : comprising superposed layers separated by air or other fluid
• CPC Class Codes: H04R 9/025 : Magnetic circuit
• CPC Class Codes: H04R 9/045 : Mounting H04R9/043 takes precedence
• CPC Class Codes: H04R 9/066 : using the principle of inertia

Abstract

A panel-form microphone characterised by a distributed mode acoustic member (12) and a transducer (63) coupled wholly and exclusively to the member to produce a signal in response to resonance of the member due to incident acoustic energy.

Claims

1. A panel-form microphone for operation in a predetermined frequency range, comprising:

a member having selected values of certain physical parameters which enable the member to sustain and propagate input vibrational energy in a predetermined frequency range by a plurality of resonant bending wave modes in at least one operative area extending transversely of thickness such that the frequencies of the resonant bending wave modes along at least two conceptual axes of the operative area are interleaved and spread so that there are substantially minimal clusterings and disparities of spacings of said frequencies, the member when resonating having at least one site at which the number of vibrationally active resonance anti-nodes is relatively high; and

a transducer coupled to the member at one of said sites on the member, the transducer being capable of converting resonance vibrations of the member due to incident acoustic energy in the predetermined frequency range into an electrical output signal.

2. A panel-form microphone according to claim 1, comprising the member (2) is mounted in a surrounding frame (1) by means of an interposed resilient support (3).

3. A panel-form microphone according to claim 1, wherein at least two said transducers (9,63) at said sites on the member.

4. A panel-form microphone according to claim 1, wherein the member (2) has a cellular core (22) sandwiched between skins (21).

5. A panel-form microphone according to claim 1, wherein the or each transducer (9,63) is a piezo-electric device.