It is known to provide a completely-in-the-canal (CIC) hearing instrument (hearing aid) in which an outer housing known as a shell of the hearing aid, is formed in a shape corresponding to the ear canal. An outside surface of that shell is in contact with substantial portions of an inner surface of the ear canal. With such CIC hearing aids, because the hearing aid housing is substantially in contact with the ear canal, a vent cavity inside the shell is provided to allow air flow through the ear canal and thus permit pressure to be equalized between the outside and the inside of the ear drum. This vent cavity or channel also reduces occlusion effects and operation of the hearing aid. Occlusion effects are known in this industry as being a change in hearing acoustics which sounds like being in a tunnel.
It is an object to decrease the size of the CIC hearing aid so that it is even smaller than the conventional CIC hearing aid.
A small hearing aid is provided which fits completely in an ear canal of a user wherein a shell as an outer housing of the hearing aid is shaped to closely surround components of the hearing aid to provide a gap between the hearing canal inner walls and the shell to allow flow of air when the hearing aid is mounted in the ear by a mounting element connected to the shell. The mounting element is provided with at least one aperture to allow the air flow. In a fabrication method, an image of the shell is shrunk to closely surround the hearing aid components while maintaining a shape of the ear canal to assure a custom fit.
For the purposes of promoting an understanding of the principles of the invention, reference will now be made to preferred embodiments/best mode illustrated in the drawings and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the invention is thereby intended, and such alterations and further modifications in the illustrated device and such further applications of the principles of the invention as illustrated as would normally occur to one skilled in the art to which the invention relates are included.
The preferred embodiments allow fabrication of a CIC hearing aid which is smaller than the prior art CIC hearing aid. The small CIC hearing aid fabricated by the preferred embodiments generally has a profile which is smaller than the ear canal, since the hearing aid shell is modeled around the components of the hearing aid such that the shell is “shrunk” to more closely approximate the size of the hearing aid components, rather than being sized to the ear canal inner walls. A mushroom cap is used to secure the small hearing aid inside the ear canal. This mushroom cap has an outer periphery contacting inner side walls of the ear canal near the ear drum and air vent apertures are provided therein as described hereafter.
The hearing aid 10 has an outer shell 14 formed of a receiver shell section 14A having a receiver 18 (
The fabrication of the small hearing aid will now be described with reference to
Creating the raw impression and scanning the raw impression to create an STL file is known prior art.
Thereafter as shown in
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As an alternative to the semiautomatic mode involving manual manipulation by an operator, a fully automated method which automatically shrinks the outer shell 14 to the components by using fixed geometries is provided. As in the case of the semi-automatic method, with the automatic method a clearance is provided between the shell (hearing aid outer housing) and the ear canal that provides the open fit previously described.
Three alternative embodiments are provided for the fully automated method. A flowchart of the first and second embodiments is shown in
At step 23 a check is made for collision between the components and the shell. At decision block 24, if there is a collision, then the shell is again shrunk. If there is no collision, as shown at step 25 a smoothing algorithm is applied. Finally, at step 26, the final detail/touch-up occurs.
With embodiment 1 of the fully automated method, the following occurs:
1. The software takes as an input an STL file that represents the receiver shell section around the receiver.
2. The software positions the receiver shell section as deep as possible inside a virtual cast representing the inside of the ear canal.
3. The software allows the user to position the other hearing aid components inside the virtual cast (ear canal), and shows a clearance equal to the shell thickness value between the other components and the virtual cast (ear canal).
4. The software grows the STL shell section towards the other components in such a way that the expanded shell section touches the virtual cast (ear canal) along the longest axis of the canal and has some free space between the expanded shell section and the virtual cast (ear canal) along the short axis of the canal.
5. The shrink wraparound the receiver and other components generated as a result of this operation shall have a minimum space required to cover the hearing aid receiver and other components.
6. The software ensures that on the face plane the shrink wrapped shell shall touch the virtual cast (ear canal) along the long axis of the canal.
7. The software ensures that the shrink wrap shall not collide with the virtual cast (ear canal). This ensures that the shell does not flop in the ear.
A second embodiment for the fully automated method is shown in
In
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In the second embodiment for the fully automated method, the following steps occur:
1. The software takes as an input an STL file format that represents the receiver shell section and an STL file that represents the expanded shell section around the other components.
2. The software positions the STL file that represents the receiver shell section around the receiver as deep as possible inside the virtual cast (ear canal) without collisions with the virtual cast (ear canal).
3. The software positions the STL file that represents the expanded shell section around the other components as deep as possible inside the virtual cast without collisions with the virtual cast (ear canal) and an STL file that represents the receiver shell section around the receiver.
4. The software grows an STL file that represents the expanded shell section around other components in the direction of an STL file that represents the receiver shell section around the receiver in such way that no collision with the virtual cast (ear canal) occur.
5. The software grows an STL file that represents the receiver shell section around the receiver in the direction of an STL file that represents the expanded shell section around the other components in such a way that no collision with the virtual cast (ear canal) will occur.
6. The software ensures that the growing surfaces of an STL file that represents the expanded shell section around the other components and an STL file that represents the receiver shell section around the receiver will meet in-between two STL files and allow the seamless merge of two STL files to form a single shell.
7. The software merges the grown surfaces of an STL file that represents the receiver shell section around the receiver with the grown surface of an STL file that represents the expanded shell section around the other components to form a single hearing aid shell.
A third embodiment for the fully automated method will now be described with reference to
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With the third embodiment for the fully automated method illustrated in
1. The software takes as an input for this approach an STL file that represents the generic small hearing aid shell.
2. The software positions the generic small hearing aid shell in the virtual cast (ear canal) in such a way that no collisions occur before an area where bending of the shell is to occur.
3. Software bends the hearing aid shell in such a way that the bent hearing aid shell fits in a virtual cast (ear canal) without collisions.
For either the semi-automated or fully automated method, the final result is an STL file which is now sent to rapid prototype equipment such as SLA Viper or other 3D printers (also known as SLA stereolithography printers). Such printers are well known in the art and accept STL files to create three dimensional final objects, in this case a fabricated shell.
As shown in the two view of
While preferred embodiments have been illustrated and described in detail in the drawings and foregoing description, the same are to be considered as illustrative and not restrictive in character, it being understood that only the preferred embodiments have been shown and described and that all changes and modifications that come within the spirit of the invention both now or in the future are desired to be protected.
This application claims the benefit of U.S. Provisional Application No. 61/041,336, filed Apr. 1, 2008, the disclosure of which is incorporated by reference herein in its entirety.
Number | Date | Country | |
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61041336 | Apr 2008 | US |