# US 9,521,495 B2 · CIC hearing aid seal and method of manufacturing the same

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- Number: US 9,521,495 B2
- Document ID: US9521495B2
- Status: Granted
- Kind: B2
- Application number: 14/428,701
- Filed: 2012-09-17
- Published: 2015-10-01
- Granted: 2016-12-13
- Earliest claimed: 2012-09-17
- Assignees: Sonova AG
- Applicants: Sonova AG
- Inventors: Erdal Karamuk; Stuart Wenzel
- Web page: https://patentgrep.com/patent/US9521495B2

## CPC

- H04R 25/652: {Ear tips; Ear moulds (hybrid ear moulds or post-processing thereof for their customisation H04R25/659)}
- B29C 43/003: {characterised by the choice of material}
- B29C 43/027: {having an axis of symmetry (B29C43/102 takes precedence)}
- B29C 43/32: Component parts, details or accessories; Auxiliary operations
- B29C 45/0001: {characterised by the choice of material}
- B29C 45/0055: {Shaping}
- B29C 45/1671: {with an insert}
- F16J 15/04: without packing between the surfaces, e.g. with ground surfaces, with cutting edge
- H04R 25/02: adapted to be supported entirely by ear
- H04R 25/60: {Mounting or interconnection of hearing aid parts, e.g. inside tips, housings or to ossicles (ear wax retarders, e.g. mounting thereof H04R25/654)}
- H04R 25/658: {Manufacture of housing parts}
- B29C 2045/0058: {removing material}
- B29C 2045/0091: {Pellets or granules, e.g. their structure, composition, length, height, width}
- B29C 2045/1673: {injecting the first layer, then feeding the insert, then injecting the second layer}
- B29K 2083/005: {LSR, i.e. liquid silicone rubbers, or derivatives thereof}
- B29K 2105/041: {Microporous}
- B29K 2995/0002: insulating
- B29L 2031/26: Sealing devices, e.g. packaging for pistons or pipe joints
- H04R 25/456: {mechanically}
- H04R 2225/023: Completely in the canal [CIC] hearing aids
- H04R 2460/15: Determination of the acoustic seal of ear moulds or ear tips of hearing devices
- H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- F16J: PISTONS {(specially adapted for dampers F16F9/32)}; CYLINDERS; SEALINGS
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29L: INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES

## Abstract

A method of manufacturing an acoustic seal for a CIC hearing aid has the steps of: embedding sacrificial particles of 50 μm to 250 μm into a silicone rubber matrix, the concentration and size of the sacrificial particles being selected to achieve a porosity of at least 40%; molding the silicone rubber matrix using a mold and curing the silicone rubber matrix; removing the sacrificial particles from the silicone rubber matrix by leaching out the sacrificial particles in a solvent; and drying the silicone rubber matrix. The seal is to surround at least part of the hearing aid and by selection of the size and/or concentration and/or the distribution of the sacrificial particles, to provide for an acoustic attenuation of at least 20 dB in a frequency range between 200 Hz and 6 kHz, with a compliance of at least 50 mm/N when the hearing aid is inserted into the ear canal.

## Claims

### Claim 1

A method of manufacturing an acoustic seal (100, 110) for retaining a CIC hearing aid (30, 230) within a portion of the ear canal (10) by contact with the wall (20) of the ear canal, comprising the steps of:
embedding sacrificial particles (70) having a size of at least 50 μm and not more than 250 μm into a silicone rubber matrix (72), wherein the concentration and the size of the sacrificial particles is selected such that a porosity of at least 40% is achieved;
molding the silicone rubber matrix into a desired shape by using a mold and curing the silicone rubber matrix;
removing the sacrificial particles from the silicone rubber matrix by leaching out the sacrificial particles in a solvent; and
drying the silicone rubber matrix;
wherein the seal is designed to surround at least part of the hearing aid and wherein the seal is designed, by selection of at least one of the size, the concentration, and the distribution of the sacrificial particles, to provide for an acoustic attenuation of at least 20 dB in a frequency range between 200 Hz and 6 kHz, when the hearing aid is inserted into the ear canal, and for a compliance of at least 50 mm/N.

### Claim 2 (depends on 1)

The method of claim 1, wherein the sacrificial particles (70) are salt particles.

### Claim 3 (depends on 2)

The method of claim 2, wherein the sacrificial particles (70) are NaCl particles.

### Claim 4 (depends on 2)

The method of claim 2, wherein the solvent is water.

### Claim 5 (depends on 1)

The method of claim 1, wherein the temperature of the solvent is from 20° C. to 80° C.

### Claim 6 (depends on 1)

The method of claim 1, wherein in said step of molding the silicone rubber matrix (72) into a desired shape a compression molding process is utilized.

### Claim 7 (depends on 1)

The method of claim 1, wherein in said step of molding the silicone rubber matrix (72) into a desired shape a liquid silicone rubber injection molding process is utilized.

### Claim 8 (depends on 7)

The method of claim 7, wherein, in said step of molding the silicone rubber matrix into a desired shape, one of a temperature curing process and a RTV (room temperature vulcanizing) curing is utilized.

### Claim 9 (depends on 7)

The method of claim 7, wherein the liquid silicone rubber injection molding process forms part of a two-component injection molding process.

### Claim 10 (depends on 7)

The method of claim 7, wherein in said injection molding process the porous silicone rubber material of the seal is combined with a component made of non-porous silicone.

### Claim 11 (depends on 7)

The method of claim 7, wherein, in said injection molding process, a hard component of the hearing aid (30, 230) having a hardness of at least 40 Shore A is overmolded with the porous silicone rubber material of the seal (100, 110).

### Claim 12 (depends on 1)

The method of claim 1, wherein the size and/or the concentration of the sacrificial particles (70) is selected as a function of the dimensions of the seal (100, 110).

### Claim 13 (depends on 1)

The method of claim 1, wherein at least one of the size the concentration of the sacrificial particles (70) is constant over the entire seal (100, 110).

### Claim 14 (depends on 1)

The method of claim 1, wherein the seal (100, 110) provides, when the hearing aid (30, 230) is inserted into the ear canal (10), for an acoustic attenuation of at least 30 dB in a frequency range between 200 Hz and 6 kHz.

### Claim 15 (depends on 1)

The method of claim 1, wherein the seal (100, 110), by selection of at least one of the size, the concentration and the distribution of the sacrificial particles, provides a water vapor transmission rate of at least 0.01 mg/h/mm2 at 37° C.

### Claim 16 (depends on 1)

The method of claim 1, wherein the silicone rubber matrix has a hardness of less than 20 Shore A after removal of the sacrificial particles.

### Claim 17

A CIC hearing aid comprising a body and at least one seal for retaining the body within a portion of the ear canal by contact with a wall of the ear canal, wherein the seal is made of a silicone rubber material having a porosity of at least 40%, with a pore size of at least 50 μm and not more than 250 μm, wherein the seal is adapted to surround at least part of the hearing aid and wherein the seal is adapted to provide for an acoustic attenuation of at least 20 dB in a frequency range between 200 Hz and 6 kHz, when the hearing aid is inserted into the ear canal, and has a compliance of at least 50 mm/N.

### Claim 18 (depends on 17)

The hearing aid of claim 17, wherein the body of the hearing comprises a lateral module (32), a medial module (34) and a flexible joint assembly (36) connecting the medial end of the lateral module and the lateral end of the medial module in such a manner that the lateral module and the medial module are movable relative to each other.

### Claim 19 (depends on 18)

The hearing aid of claim 18, wherein at least one of the lateral module (32) and the medial module (34) is provided with said at least one seal (100, 110) and wherein said silicone rubber material has a hardness of less than 20 Shore A.

### Claim 20 (depends on 19)

The hearing aid of claim 19, wherein said at least one seal comprises a first seal on the lateral module and a second seal on the medial module, and wherein the first seal (100) of the lateral module (32) has at least one of a porosity and a pore size which is different from that of the second seal (110) of medial module (34).

### Claim 21 (depends on 20)

The hearing aid of claim 20, wherein the compliance of the second seal (110) of the medial module (34) is higher than that of the first seal (100) of the lateral module (32).

### Claim 22 (depends on 21)

The hearing aid of claim 21, wherein second seal has a water vapor transmission rate that is higher than that of the first seal (100) of the lateral module (32).

### Claim 23 (depends on 20)

The hearing aid of claim 20, wherein the second seal (110) of the medial module (34) has a sound attenuation that is lower than that of the first seal (100) of the lateral module (32).

### Claim 24 (depends on 17)

The hearing aid of claim 17, wherein the hearing aid (30) is sized and shaped to be worn in the ear canal (10) in a manner that a medial end of the hearing aid is located not more than 4 mm from the tympanic membrane (12).

### Claim 25 (depends on 17)

The hearing aid of claim 17, wherein said at least one seal comprises at least two seals and comprises a single module (240) which is provided with two of the at least two seals (100, 110), and wherein the two seals are arranged axially spaced apart on the module.