Flexible substrate transducer assembly

• US 6,324,907 B1
• Filed: 11/29/1999
• Issued: 12/04/2001
• Est. Priority Date: 11/29/1999
• Status: Expired due to Term

• Current Assignee: TDK Corporation
• Original Assignee: Microtronic A/S
• Inventors: Kristensen, Poul Rosenkilde, Halteren, Aart van
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US09/450,994
• Time in Patent Office: 736 Days
• Field of Search: 734/31, 737/03, 737/19, 737/20, 737/25, 737/26, 737/27, 381/189, 381/190, 381/191, 381/355, 310/327, 310/334
• US Class Current: 73/431
• CPC Class Codes: H04R 19/005 using semiconductor materials
• CPC Class Codes: H04R 2225/49 Reducing the effects of electromagnetic noise on the functioning of hearing aids, by, e.g. shielding, signal processing adaptation, selective (de)activation of electronic parts in hearing aid
• CPC Class Codes: H04R 25/00 Deaf-aid sets , i.e. electro-acoustic or electro-mechanical hearing aids; Electric tinnitus maskers providing an auditory perception electrical stimulation of auditory nerves to promote the auditory function A61N1/36038; optical stimulation of auditory nerves to promote the auditory function A61N5/0622

Abstract

A flexible substrate transducer assembly integrates a transducer or transducer system with built-in signal processing capability, and a flexible substrate. The flexible substrate provides connectivity between the transducer system and electronic equipment which house the transducer assembly. This assembly is adapted for use in compact equipment such as mobile phones and hearing instruments that benefit from the small outer dimensions achievable for the assembly.

Claims

1. A flexible substrate transducer assembly, comprising:

a flexible elongate member having an upper and a lower surface and comprising at least two conductors that each has an exposed part at a first end of the member and a contact pad at a second end of the member,

a transducer system adapted to generate or receive a transducer signal on two or more signal terminals and to convey the transducer signal from the two or more signal terminals to the respective contact pads, the transducer system being attached to the upper surface at the second end of the flexible elongate member,

a lid attached to the upper surface of the flexible elongate member and covering and shielding the transducer system and a supporting area of the flexible elongate member from an external environment,

wherein the supporting area of the flexible elongate member comprises one or several holes extending through the flexible elongate member so as to provide a first passage to the external environment between the lower surface of the member and the transducer system covered by the lid.

2. A flexible substrate transducer assembly according to claim 1, wherein the lid comprises an electrically and/or magnetically conductive material.

3. A flexible substrate transducer assembly according to claim 2, wherein the lid is fabricated in a moulding process or in a cold stamping process or in a deep draw process.

4. A flexible substrate transducer assembly according to claim 1, wherein the lid comprises a material selected from the group consisting of copper, iron, steel, silver, gold, tin, and aluminum.

5. A flexible substrate transducer assembly according to claim 1, wherein the lid is fabricated from a non-corrosive alloy.

6. A flexible substrate transducer assembly according to claim 1, wherein the lid is electrically conductive and connected to at least one of the at least two conductors of the flexible elongate member.

7. A flexible substrate transducer assembly according to claim 6, wherein the electrical connection between the electrically conductive lid and the at least one of the at least two conductors is provided by an electrically conductive glue.

8. A flexible substrate transducer assembly according to claim 6, wherein the electrical connection between the electrically conductive lid and the at least one of the at least two conductors is provided by a rolling or a welding process.

9. A flexible substrate transducer assembly according to claim 1, wherein the flexible elongate member comprises a flexible circuit strip.

10. A flexible substrate transducer assembly according to claim 1, wherein the at least two conductors comprised on the flexible elongate member are arranged on a single surface of the upper and lower surfaces of the flexible elongate member.

11. A flexible substrate transducer assembly according to claim 1, wherein the flexible elongate member comprises an electrically conductive intermediate layer arranged between the upper surface and the lower surface to provide EMC shielding of the at least two conductors.

12. A flexible substrate transducer assembly according to claim 1, wherein the transducer system comprises a first die and second die.

13. A flexible substrate transducer assembly according to claim 12, wherein the first die comprises a transducer adapted to generate the transducer signal on the two or more signal terminals in response to a measured physical quantity, and

the second die comprises an electronic circuit adapted to receive and process the transducer signal and convey a processed transducer signal to the contact pads.

14. A flexible substrate transducer assembly according to claim 13, wherein the electronic circuit comprises an analogue-to-digital converter.

15. A flexible substrate transducer assembly according to claim 12, wherein the transducer system comprises an acoustic sound pressure transducer.

16. A flexible substrate transducer assembly according to claim 15, wherein the acoustic sound pressure transducer comprises a miniature silicon microphone.

17. A flexible substrate transducer assembly according to claim 16, wherein the lid comprises one or several holes providing a second passage for the external environment to the miniature silicon microphone,

thereby forming a directional microphone by a joint acoustic effect of the first passage in the flexible elongate member and the second passage in the lid.

18. A flexible substrate transducer assembly according to claim 16, wherein the miniature silicon microphone comprises a membrane and a back plate, the membrane facing one or several holes extending through the member,

thereby providing a microphone wherein the lid functions as a back chamber and wherein a sound inlet port is formed in the supporting area of the flexible elongate member.

19. A flexible substrate transducer assembly according to claim 12, wherein the first die comprises a actuator adapted to receive a processed transducer signal from the two or more signal terminals, and

the second die comprises an electronic circuit adapted to receive and process the transducer signal and convey the processed transducer signal to the two or more signal terminals.

20. A flexible substrate transducer assembly according to claim 19, wherein the actuator comprises a miniature sound pressure generator responding to the processed transducer signal.

21. A flexible substrate transducer assembly according to claim 19, wherein the electronic circuit comprises a digital-to-analogue converter.

22. A flexible substrate transducer assembly according to claim 1, wherein the lid is substantially rigidly attached to the upper surface of the flexible elongate member to restrain the supporting area of the flexible elongate member so as to increase a stiffness of the supporting area.

23. A flexible substrate transducer assembly according to claim 1, wherein at least a part of the transducer system is attached through an intermediate resilient layer adapted to absorb stress forces between the flexible elongate member and the transducer system generated by a differing thermal coefficient of expansion/compression between the flexible elongate member and the transducer system or generated by external forces.

24. A flexible substrate transducer assembly according to claim 23, wherein the intermediate resilient layer comprises a resilient glue joint or joints.

25. A flexible substrate transducer assembly according to claim 23, wherein the intermediate resilient layer comprises a resilient piece of foil, foam or rubber.

26. A mobile phone comprising the flexible substrate transducer assembly according to claim 1.