Mechanical acoustic filter by erosion etching

• US 20050135648A1
• Filed: 12/18/2003
• Published: 06/23/2005
• Est. Priority Date: 12/18/2003
• Status: Active Grant

• Current Assignee: Knowles Electronics Taiwan Ltd. (Knowles Corporation)
• Original Assignee: Knowles Electronics Taiwan Ltd. (Knowles Corporation)
• Inventors: Lee, Pei-Chau
• Granted Patent: US 7,165,647 B2
• Time in Patent Office: Days
• US Class Current: 381/355
• CPC Class Codes: H04R 19/04 Microphones H04R19/01 takes precedence

Abstract

The invention relates to a mechanical acoustic filter using erosion etching technique to be used in electric condenser microphones. The invention is to be formed as one or a plurality of boards by erosion etching according to different requirements. The boards can be of boards for printed circuit boards, ply boards, or of other materials. Every etched board has corresponding paths. which after the boards are assembled, form an acoustic filtering path that not only can extend the length of the path to filter out high frequency noise more efficiently, but also can reduce the entire volume of the microphone assembly.

Claims

1. A mechanical acoustic filter by erosion etching comprising:

a board formed from a plurality of individual boards using erosion etching based on individual needs, of wherein the individual board being replaced with printed circuit board, ply board and boards with different materials;

paths being etched on each individual board so when the individual boards are joined together, resulting in a wave filtering path being formed efficiently from the corresponding bending and turning grooves.

2. The mechanical acoustic filter by erosion etching as recited in claim 1, wherein at least one wave filter by erosion etching can be made on a single print circuit board by applying erosion etching.

3. The mechanical acoustic filter by erosion etching as recited in claim 1, wherein when the board is made from a single board, the radius of the wave filtering path is smaller formed by erosion etching than that formed by injection molding.