High compliance headphone driving

• US 5,181,252 A
• Filed: 10/16/1991
• Issued: 01/19/1993
• Est. Priority Date: 12/28/1987
• Status: Expired due to Term

• Current Assignee: Bose Corporation
• Original Assignee: Bose Corporation
• Inventors: Sapiejewski, Roman, Breen, John J.
• Primary Examiner(s): Dwyer, James L.
• Assistant Examiner(s): Chan, Jason
• Application Number:
  US07/782,874
• Time in Patent Office: 461 Days
• Field of Search: 381/181, 381/183, 381/158, 381/197, 381/74, 381/202, 181/166, 181/171, 181/172
• US Class Current: 381/372
• CPC Class Codes: G10K 11/17857 Geometric disposition, e.g. placement of microphones
• CPC Class Codes: G10K 11/17875 using an error signal without a reference signal, e.g. pure feedback
• CPC Class Codes: G10K 2210/1081 Earphones, e.g. for telephones, ear protectors or headsets
• CPC Class Codes: G10K 2210/3026 Feedback
• CPC Class Codes: G10K 2210/3217 Collocated sensor and cancelling actuator, e.g. "virtual earth" designs
• CPC Class Codes: H04R 1/1008 Earpieces of the supra-aural or circum-aural type
• CPC Class Codes: H04R 1/1083 Reduction of ambient noise active noise reduction per se G10K11/175; protective devices for the ear, e.g. providing acoustic protection A61F11/06
• CPC Class Codes: H04R 5/033 Headphones for stereophonic communication details thereof, e.g. relating to batteries, cables or control elements H04R1/10

Abstract

An active noise reducing headset has a high compliance diaphragm. Structure limits the maximum excursion of the diaphragm so that the voice coil does not escape the air gap. Structure, such as indentations in the diaphragm, prevent unrecoverable diaphragm collapse.

Claims

1. A headset comprising:

at least one earcup having a front cavity and rear cavity with front cavity and rear cavity compliances respectively,

a baffle separating the front and rear cavities,

a high compliance driver with a driver compliance that is greater than said rear cavity compliance having a diaphragm joined to a voice coil normally residing in a gap mounted on the baffle, and

an active noise reduction system coupled to said driver.

2. A headset in accordance with claim 1 and further comprising limiting structure limiting the maximum excursion of the diaphragm so that the voice coil remains at least partially in said gap.

3. The headset set forth in claim 2 wherein said limiting structure comprises a plurality of plastic elements, placed such that said plastic elements contact the diaphragm where the voice coil is joined to said diaphragm.

4. The headset set forth in claim 2 wherein said limiting structure comprises a fine wire mesh screen shaped so as to contact as much of the surface of the diaphragm as practical at its position of maximum allowed outward excursion, preventing further movement.

5. The headset set forth in claim 1 and further comprising means for recovering from collapse of the diaphragm including indentations in the diaphragm such that the diaphragm recovers its shape if collapsed.

6. The headset set forth in claim 1 and further comprising raised portions on the surface underneath the diaphragm preventing unrecoverable collapse of said diaphragm.