Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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- "Method of preparing an otoplasty or adaptive earpiece
lndividually matched ~o ~he shape o~ an audltory canal".
The invention relates to a process for making otoplas~ies
or adaptlve earpieces, consisting of one par~ or several
independentl~ pr~cessable par~s, whi~h are individually
: matched to the shape o~ the audltory cana:L.
f a~ adap~lve ea~piece or, in par~icular, an otoplas~y
i~ to be individually produced today ~or an in the-ear
hearing aid, thic requires a large number of process
. steps which are extremely ~ime-consuming, wor~-intensi~e
: and th~s expensive.
. The following work must essentially be per~ormed
manually:
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1. Pro~uc~ion o~ one mo~e ear impression~ o~ th~
patient;
: z. processin~ o~ ~he ear impression ~or production of a
mold. To do this, excess ma~erial must be removed
~rom the ear lmpresslon, small ~laws in ~he
: , impression repair~d and some part~ of ~he ear
imp~e~sion increased in size. Finally, the ear
i~press~on must b~ immersed in a wax or similar ~luid
to smooth the surface.
. Pin~lly, a mold is made ~rom the ear impression which
may consist o~ plaster, a gel or silicone re~in.
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4. A polymerizable liqu~d synthe~ic resin in the des~red
mixture i5 then prcduced, poured into the mold and
polymerized a~ le~st par~ially~ I~ th~ produet 1~ ~
Bl~ell for an indi~ ually tailored in-the-ear hearing
aid, mos~ or'' the liguid ~ynthetic resin must be
poured out of the mold again be~ore it completely
polymerizes .
5. The mold is normally destroy~d when the Gas~ is
remo~ed ~rom it~
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. The adap~lve earplece or otoplasty is su~s~qu~ntly
ground to the cor~ect size and re~uired appearance.
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7. Norma}ly, lt i then nec~ssary ~o produce a
ventilation channel, which c~n be done in dif~eren~
WAyS .
. Arter thls, a sound outle~ openi~ must be p~oduced
by ~rilling.
4. Finally, the adaptive earplece or otoplasty must be
pol ished .
If the cast i~ intended :eor ar~ in-'che-ear hearing aid,
~urther pJ:ocess teps ar~ add~ionally necessary:
1 n . 1~ must ~e ensur~d ~ha~ there i~ su~icient spa~e for
the hearing aid components ~microphon~, ampllfler,
battery, ~tolume control, earphone e~c. ) .
. The earphone ~nust be inser~ed as deep as po~si~le in
the part c~ th~o otoplasty locat~d ln the auditory
canal and qe~ured here. O~en, t~ere is very little
spac~ her~ to accG- ~date both th~ earphone and the
ven~la~ion channel, which nonnally has a circular
cro~6-s~ctiorl, ln the par~ o~ the otoplasty whi~h ig
lo~at~d deeE: ln the auditory cana 1.
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12. In addltion, a telephone coil should also b~
accommoda~ed somewhere inside ~he otoplasty.
13. In addi~ion, it may be the ca~e that ~he miorophone
also has to ~ lo~ated indi~r~dually.
14~ Finally, the cov~ pla~s mus~ be secured on the
otopla~ty, either by bonding or polymerization.
Overall, this normally ~ollowed method ~hus consis~s of a
lar~e number o~ manu~l proces~ ~teps which require a
gr2at deal of time and which neverth~less inv~lYe a goo~
deal o~ uncertainty, since many of the steps are
d i f S icul~ to monitor and chec~ . The ~11 thickness ~nd
the interlor cavity o~ an otoplasty for in-the-ear
hearing aids can be mer~tioned as exa~r.ples o~ t~i~, sin~e
these o~ten deviate ~rom the desi~ed ~lues when the
m~nual method is used. In some cases, excess ma~erlal has
to be removed ~oTn ~he irtterior cav~ty with a d~ntal
dri Ll or grinding wheel ln or~er to c:reate sufficient
space for the earphone, Yentilation channel etc~ HoweYer,
ev~3n ~his met~od i5 not well de~ined and suppl ~ es
practlcally unpredictable r~sults.
For this reason, ~any atte~npts have al~eady been made ~co
Rolve thi~ problem, b~cause in-the-ea~ hearing aids
manu~ac~ured ~ing ~hese methods in t.~e pas~ have mostly
been of poor quality and possessed hardly foreseeable
character~ sti~s .
Modular in-the-ear he~r~ng aid3 where a module which
a I ready c~n~ains all c:omponents o~ ~he haaring aid is
~olcled into an indivldually produced otoplasty have no~
pro~en to be e~pec~ally suc~ess~l, probably partly
because ~hey are normally sli~h~ly largex. Thi3 i~
becau~e the components within the mo~ule are arranged in
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fixed positions. ~n ad~i~ion, these hearing aids often
had the appeaxance o~ composi~s or hybrid devices.
~ It is the task o~ ~he present invention to:
. completely o~ almost completely ~utomate production
o~ individually ma~ched adapti~e earpiece~ or
housi~g~ o~ in-the-ear hearing aid~ or otoplasties;
2 . permi~ optimum utiliza~ion o~ ~he space availa~le ~n
the audi'ory canal and ln the outer ear, with the
result that the smallest possible heari~g aid can b~
produced:
3. ensur~ optimization~o~ position and ~Drm of all
interna} functions and components o~ an in-the-ear
hearing aid and
4. to des~ribe method~ ~or manu~a¢ture oP well-de~ined
h~ar~n~ ~id9 and a~apti~e earpie~es o~ constantly
uniform quali~y, whlah al50 appear particulaxly
attractl~e ~rom a ~osmetic point of view at the ~ame
time.
Thi~ task which ~orms the b~ o~ the invention ls
; ~olved by the invention ~y way of the following proce~
steps:
a~ ~irect or ind~rec~ ~r~ing o~ ~he shape of th~
au~itory ~anal and conver~ion o~ the values obtalned
lnto digi~al ~o~m;
b) con~er3ion of th~ digital reprece~tation o~ th~s
~ape in~o ~ three-dimensional o~ mult--dimensio~al
computer model o~ the outer ~hap~ o~ the otoplasty or
~daptlve earplece:
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) selection o~ the various comp~nents/~unctiQns ~or the
lnside of the compu~er model with simultaneous
esta~lishment Of ~he wall thickness and optimization
o~ ~he positions o~ the ~omponents/~unctions ~or best
possible operatlon and minimu~ bul~;
d) computer-controlled produc~ion of an otoplas~y or
adaptive earpie~e ~rom the d~ta thus ob~ained ~rQm
the optlmlzed three-dimensional computer
representation of the o~oplas~y or a~aptive earpi~ce.
The invention will now be explained in more detall in
conjunctlon Wi~h ~he enclos~d drawing~ on the ha~i~ of
various example e~bo~imen~s, whereby the ~irst three ~ ~ ~
sections o~ the basic solution are e~sentially common to
them all.
The draw~ngs show ~he following: .
Fiq. 1 a cross-sectional vlew o~ ~n in-the-ear hearing
aid,
Fi~. ~ a ~chematlc cross-sectional view o~ an adaptive
earpiece;
Fig. 3 a ~low chart or sequence diagram o~ the p~ocess
;:s~eps in ac~ordan~ w~th claim 1;
,
Fi~. ~ a ~low chart o~ ~he me~hod in a~:~ordance w~th
~laihl 4 7
Fi~. 5 representations ~ individual cross~sections of
an ear impression obtained ~y ~acing:
:
Fi~. 6 computer representat~on o~ cross-section~l
plane~ obtained by t~a~ing;
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Fig. 7 representa~ion of the outer sur~ace o~ ~n
otoplasty as a three dimensional model
calculated using t~e ~inite element method;
Pig. 8 representation of ~h~ thre~-di~mensional
::omputer model o~ t}~e otopla~ty with alrea~y
c:alc~ulated wall tAickness for de~inition o~ the
interior ca~rity at ~he inner su~ace:
F ig . 9 ~low char~ accordance With the meth~d
de~cribed i n claims 21 and 22;
F i q . 10 ~low cha~t o~ the method in accordan~e with
~~ claims ~?, 28, 31, by p~od~cti~n o~ cro~s~
sectional planes ~nd stacking or these "slices"
on top o~ e~ch other;
Fig. ll ~low chart o~ the extru~ion method in
a~cordance With claim 32;
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F~g . 12 schematiG d~ agrarn o~ the build-up o~ an
o~oplasty or adaptive earpiece using ~he
.. e~ru~ion method;
.
Fig. 13 ~low c:hart o~ a subtxactlve m~thod ~r
represerl~ation o~ ~oth the ~nner and outer
contou~s o~ an otoplasty or adaptlv~ earp~e~e:
Fiq. 1~ shaping o~ the outer contours ~rotn block~ with
p~e-pxoduced in~erior aaY$ty as a ~low ch~rt:
i g . 15 schematic dlagram of' tha subtract ive multl-
bloc~: me'chod7
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Fiq. 16 schema~c cliagram o~ two finished parts o~ an
otopl~5~y;
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Fi~. 17 schematic diagram o~ parts or blocks with pre-
produced lnterior cavity ~o be used f or an
otoplas~y ln con~unction with the subtract~ve
me~hod.
Fig. 1 schematically shows an in-the-ear hearing aid with
a shel 1 or o~oplasty 1 which is closed ~y a cover
pl~te 2. Th~ hear~ng ~id contains a microphone 3, an
electronic amplifier section 4, a battexy 5, an earphone
6 and flnally a 60und outlet channel 7a as well a~ a
pr~ssure ~ompensati~ or ventilation channel 8a.
Fi~. 2 show~ an ~dapti~e earpiece o~ ear t~p 9 with a
sound t~be 10 leadirl~ to a hearing ai.d (not shown), a ~ ~~ ~~
.sound outlet channel 7b and a ventilation channel 8b.
;
rn principle, ~he producti~n method for both embodim~nts
is essentially the same, apart ~rom the fac~ that in one
t:aSe (hearing aid) componen~-~ are inoluded, while this i~
no~ normally so i~ the other case.
~hs general princlple oP the invention ~s shown in
Fig. 3. ~ h~atically ~hown ear 11 possesses an
auditory canal 12, whose contours ha~ to be determined.
Thi~ ~an be don~ statically and dyna~ically. This will be
d~scu~ed in more detail later on.
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In ~.he case shown in Flg. 3, the cont~ur~ o~ ~he ~uditory
c:anal are determ~ned at A and ~ itally stored in a data
b~se l 3 . Thi~ digital data is con~r~rted into a ~chree -
d imension 1 c~mputer model ~ the otopl~sty at 3 and
~aved in ~ data ~ore 14 . All componentsf function~ f~r
the in~he-ea~ hear~ng aids or a~aptive eaxp~ece~ are
stored in a ruxt;~e~ data base ~S. ~hiE~ sh~uld be
understood a~ ~eaning the~t the dimen~ions and per~ornance
da~a o~ all available ~omponen~s and func~ions are.stored
in ~hi~ data base so that they can be called when
requir~d, i.~. also v~xious sizes o~ earphones,
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microphones, amplifler sectlon~, batteries, etc. This
data base wlll be c~eated if it does not already exist
and constantly ke~t up to date and supplemented or
modernized.
The data stored in the dat~ ba~e~ 14 and 15 i~ then used
at C in or~er to optimally in~orporate the neces~ary
~unctions/components in the ~hree-dimensi.on21 computer
~odel, e.g. o~ an in~t~e-ear hearing aid. As a result of
this, a comple e ~odel o~ ~he otoplasty or adapti~e
earpiece i6 o~ained in the memory 16, which may al~o be
part o~ a general data base. The okoplasty 17 i~ then
produced in a computer-controlled production process ~ on
the basls o~ this model o~ the otoplasty or adaptlve ---
~arpieca stored ln the computer, whereby th~ otoplasty is
then sub6e~uently processed in the usual way. Thls
naturally also appltes ~g w~ll to an ~daptive eaFplece.
A static method ~or tracing the contours o~ a~ auditory
~anal i~ shown in pri~clple in Flg. 4. An ear lmpre~sion
L8 i~ made Or the ear 11 with it5 auditory canal la at
Al, ~he ~im0nsions o~ this ~igitized at A2 and th~s
in~orma~on then stored in a memory area 13. As be~ore,
this data is converted in~o a 3-dlmensional computer
model at B and then ~tored in a data base ~t 14.
conversion o~ the contours of th~ ear impression ~an
occur in a wlde varl~ty o~ ways. Por example, the
conto~rs o~ the ear impression can be recorded without
deetruetion by means of radiat~on, e.g. X-~ays or
ultrasound, passing through the ear impression, wit~
~cann~ng taking place ln unlform successlve cross-
s~ctional plane , ~or example. The ~xternal contour~ of
the ear impres~ion can also be de~erffli~ed by ~eans o~
laser lnt~r~eromet~y,
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A ~utther pr~c'eical possibi~ity is ~o divi~e or cut the
ear impression in~o thin layers in successive s~eps and
to r~3cord the dimensic!ns of thest3 layers with a video
camera, ~or example.
~hese method~ can be improved furthe~ b~r embedding the
ear impression ln a plas~ic blocX with contrasting color~
Thi~ impro~le~ reco~di~g o~ the contour~ both ~or
destruction-~ree ~cannlng and for cutting. These cross-
sec~ions may then appear as shown in F~. 5, ~or example.
It ~ust be noted here that 'che cut~ or cross-sectional
plane~ nee~ not necessarily possess un ~orm distan~es or
~.lniform laye~ thicknesses. It is sufficier,t i~ a new
cross-sectlon is determined only when this di4~ers frorQ
the prevlous cross-section by previously defined mini~,lum
d imenslon5.
Finally, it i~ also passible to mill or grind o~ ~rom
the ear lmpression in successive steps thin layers o~
~ni ~orm or non-un~ form thickness and to then trace and
digi~ally s~ore ths resultant sur~ace.
rn addition, the contoux8 o~ the auditory canal can also
be traced by mean~ o~ ontac:tles~ ~cann~ng, e.g. by
ul trasound. In thi~ speclal c~se, lt is even p3ssible to
achiev6~ dynamlc: r~cordin~ o~ the auditory canal contour~.
In principle, ~ecor~ing o~ the conto~lrs o~ the ~uditory
canal m-~st b~ ~een spatially, i . e . ~n a multi-di~nenslonal
recording ~ystem which ~cords and describe~ ~h~ lnterior
space o~ the auditory canal. Howe~rer, since the aontour~
oS t~e aud~tory car;al c~hange a~ a result o~ peaking,
eating, drln~ing etc:., this me~hod of ac~uiring the data
on ~he oontou~ o~ e audltory canal pro~tides sc:anr ing
v~lu~e~ which ~asy in l;ime t i . e . a ~ourth variable), wh~ch
means ~hat these changi2lg contours can also b~ taken into
con~dera~ion~ It is thu~ pos~ible to real~ze an even
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be~ter otoplasty or adaptive earp~ecs ~orm than wi~h the
s~atic method.
~ig. 6 then shows a co~puter representation o~ cross-
sectlons obtalned by scanningc
When ~he digltlzed data oP the auditory canal ls
available in the memory, it i~ possible to start with
conversion o~ thi~ data u~ing algorithms ~nown ~rom the
~ie~d of CAD/C~M technology to produce a three-
dimen~ional computer represen~atlon o~ ~he exte~nal
contours o~ the otoplas y or adap~i~e earpiece, e.g.
u~ing the flnit~ element method. This is shown
schematlc~lly ln ~ig. 7 (also refer--to Fig. 3, i~ms 14,
and 16 ~nd C~. In this contex~, it is also then
possible to immediately define the minimum wall
thickness, which simultan~ou~ly repre~ent~ the outermo~t
boundary su~a¢e ~or tha components/function~ and their
optimum arrangement. Thls 1~ ~hown in Fi~ ~ 8, al~o in a
computer representation.
This conversion can of cours~ be per~ormed eithe~
interactively o~ ~ully computer-controll~d. After this,
Lt ls necessa~y to de~ine the ~hamber~ ~or the earphone
~nd the compensating channel, whereby the compe~sating
channel is pro~ d either with ~ uni~orm cros~-sec~ion
or with a stepped, pre~erably multlply ~epped, ~ross-
~ection in order to achieve a low-pass ~lter e~ect
be~ore the channel is then di~ltized and represente~ in a
thre~-dim~nsional comput~r model. The p~ogram could then
~dapt ~he path o~ the com~ensatin~ channel to t~le given
conditions in order to permit optimU~ utt ~iza~ion or~ the
availa~le 6pace inside ~e o~oplasty. The earphone
~harruber can then be taken ~rorn the d2~ta base 15 or ~rom a
data ba e library of three~ ional 3~0dels and
d ~ f ferer~t ~unction~ . Thi~ allow~ ~e earphone to be
arranged as deep as possible in the ~ nner end o~ the
otoplasty, ~or exam~le. Howe~er, i'c ls also necessary to
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perfo~m a compuker-controlled che~X to establish whether
the earp~one can be inserted up to the end o~ the
ot~plas~y located furthest into the auditory canal when
it i9 finally inserted in the device.
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; In the same way, it is possible to select the amplifier
bleck, microphone cham~er and, where approprlate, a
teleph~e coil cha~ber ~rom the data b~se for components
~unctlons ~nd to interactively or automa~ically arrange
these in an optimum position inside the otoplasty.
.
When all ~unctions~o~ponen~s have been arranged in their
optimum pvsition~ in the three~dimensional computer
model, i.e. no~ physically, it may be necessary ~o fill
i n a small amount o~ aterial" here arld there Ln order
to e~BUre proper manu~ac~ure la~er on. It may al~io be
necessary to provide a numb0r o~ support parts ~or some
production ~ethod~ whlch initially facllltate production
but ~hich must be removed later on.
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~r~e actual productlon process w~ll now be described on
the basis o~ the three-di~ensional co~putex model o~ th~
atoplaety or a~aptive earpiece stored $n the memory or
~ata ~a~e.
In the actual computer~controlled produc~ion ~ the
~toplasty or adaptive earpiece, ~ basic distinction i
ma~e between two variant~i, namely an additiv~ ma~hod,
i.~. build,up o~ ~he otoplasty or adap~iYe earpiece in
successive s~eps, either continuou or discontinuous, and
a subtractive ~ethod, where pre~ab~icated bloc~i are u~ie~
~rom whlah mat~rial is removed until the ~inal sh~pe o~
~he adap ive earpiece or otoplas~y has been achleved.
Thiq will be ~e~c~ibed in detail lat~r on.
Fig. 9 ehowsi a ~irst pos-qlble method.
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On the basis o~ the data stored in the data ~ase 16, this
~hree-dlmen~ional compu~er model i~ converted in o a
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number of ~ross-sectlons in ~tep Dla. These cross-
sac~ions may be equidistan~, but need not be. They need
AlSO not be plane-parallel and horizontal. The preferably
~wo-dimens~onal cross-sectional planes are stored in a
data base ls~ U~n~ this da~a base, the o~oplasty can
then be produ~ed by produ~ing the individ~al cross-
secti~nal planes success~vely and on top oP each other,
underneath each other or nex~ to each other and then
join~n~ them ~ each other. Thusl for example, a stero-
litho~xaphic or sim~lar method can be used as step ~lb.
The resul~'is a "raw p~oduct", e.~. an otoplasty 20,
which must be reworked in step Dlc in or~er to obtain the
finished o~oplasty 17.
These methods ~an ~e per~ormed in quite di~erent way~.
~or examp~, a con~alner with activated llquid syntheti~
resin may be located on a ~omputer-controll~d movable
pla~orm. B~ targe~e~ use o~ r2diatlon directed at the
~ur~ace o~ ~he llquid synthetic resin and causing at
le~t part-polymeri2at~0n oY the synthetic resln, i~ is
possible to generate a first cross-~ection o~ th~
o~oplasty. A~ter th~s, it i necessary to lower the
plAtform by thç th~aXness o~ a layer a~ter each cro~-
~ection 1~ complete~ so that t~e next cross-~tional
plane on the sur~ace o~ the liquid ~ynthetia resin can be
produced in ~he Bame way. ThiS i~ ~hen contlnued until
t~e a~ le~st p rtial~y polymerized otoplas~:y can at last
~e removed from the con~ainer. The Sa~e naturally al~o
applie~ to production o~ an adaptive earpiece.
rn a dif~erent me~hod~ a contaln~r located on a plat~o~m
cantain~ ~ liquid synthetic resin whlch ~an be a~tivated
by an activator. An in~ection nozzle whose position can
be controlled in three dime~sions is located a~ove the
container throuqh whlch an acti~ator can be lnjected in~o
the li~Uid synthetic resin ~rom b~ttom to top in a
prog~es~ manner, ~ither intermltten~ly or
continu~u~ly, in order to then ~uild ~p the otoplasty in
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the li~uid syntheti~ resin as he la~ter hardens at least
partially when the syntheti~ resin and activator come
together. ~is can ~e supported by supplying heat by IR
la~ps or by the presence o~ UV radi~tion.
Fiy. 10 ~hows ths principle o~ thls method.
s~artlng ~rom ~h~ data base 16 i~ which the three-
dimensional computer model is tored, this model .~3
converted in step D~a ~nto a number o~ two-dlmensional
cross-sec~lons and ~hen stored in the da~a base at ~1.
The ad~ptive earp~ece ~s then produced at step D2b by
injection o~ the actl~ator in the liquid ~yn~hetic resi~
maSc~ thu~ producing the raw model ~hown ~t 22, which -i5- - -
then reworXed at D2c to ~inally produce the fin~hed
~toplasty 17.
The same na~urally also applies to an a~aptive ~arpie~e.
A ~ur~her elegant method i5 to ag~in derive two-
dlmen~lonal cross-sec~lons Prom the ~hr~e-dimensional
computer model stored in ~he d~ta base 16 and to then
~tore ~hese in a ~ata base similar to 19 in Flg. 3 or 21
in Fi~. 10. A compu~er-controlled cutter ~s ~hen used ~o
produc~ th~ individ~al cross-s~t~n~l pl~nes, cutting
the individ~al oross-sections out o~ a synthetic resin
rilm or ~ynthet~c resin plate, which may alre~dy be
partially polymerized, ~or example, whereby these cro~-
section~ are then s~acked on top o~ each o~her and joined
toqet~er~ A las~r is ~uitable a~ a cut~er, pa~tlcularly a
so-called Eximer laser funGtionlng in the ultraviolet
range. The base sur~ace ~or ~he synthetic resin ~llm or
th~ synthetic resin plate ~ay be a con~ey~r belt with the
~ilm or ~heet located on top o~ it, for example, sa tha~
tha cross~s~ectlons ca~n be produ ::e~l c~nsecu~i~.rely .
Alt~rnatiY~ly, the base ~ur~acse may a~so be a ro~atin~
wheel. It is al30 po~ible tc) supply ~aterlal in the ~a~e
way as ~r a punah and to produce, stack and j oln ~he
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indi~idual cross-sections successively, i.e. gluelng,
welding, screwing or bonding in~o one piece ~y
polymerization.
~urther pa~sibllity ~s to produ~e these cross-sections
~ in a ~ind o~ printin~ method similar ~o that used in a
ink-~et prlnter, for example, by consecutively praducing
successive cross~sect~ons using ~ kind of printi~g
technique an~, aPter at le~st partial polymerization
w~ich should already také place a~ the prin~ing
opera~ion, by then stac~ing ~hem ~n ~op o~ eac~ other and
joining ~hem to form an otopl s~y. A~ otoplasty produce~
in this way must o~ cou~se also be rewo~ked in the normal
manner to produce the ~inlshed otoplasty 17.
Fig. 11 show a further sui~able me~hod for productlon of
!.' ~n otopl~sty or adaptive earpiece. Starting from the data
ba~e 16 with the three-dimensional ~mputer moder stored
in it, a three-di~ensional path is generated in 6tep D3a
which des~ribes the three-dimensional compu~e~ m~del of
the otoplasty or adap~ive earpi ece on all sides. This is
: stored in the data base 23. In order ~o produce the
o~opla~ty, an extrusion nozzle whose movement~ can be
controlled in three d'mensions ~ ~rranged a~ove a
plat~orm from which synthetic resin i-Q contin~ou~ly or
discontinuously extruded, whereby thQ resin polymerizes
. at lea~t partlally upon emergence ~rom the noz~le and
applicatlon onto the plat~orm, unti~ ~he ex~ruded body o~
an otoplasty as shown ln 24 has been produced. This is
then rewor~ed in th~ usual way ln step D3c to produce ln
turn the ~inished otoplas~y 17
:'
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,.
16 2~7~
The same naturally also applies to production o~ an
adaptive earpiece.
Fig. 12 schematically shows ~e same met:hod. ~n extrusion
de~ice 26 whose movement~ can be controIled in three
~ime~sions and which is equlpped wi~h an extrusion
nozzle ~7 is located above a plat~orm 25 rom whl~h ~
stran~ o~ a polymer~zable liqui~ or pas~y synthe~iG resin
is applied ~o the p~at~orm in order to orm the
o~oplas~y. ~or this purpose, ~he no~le 27 may also ~e
kept ~tatlonary and the pl~orm made to execut~ a
corresponding multi-dimensional movement. However, it may
also be exped$ent to control both ~he position of the
no~le 27 and the position o~.the platform 25.
The subtractive met~od will now be explained ln the
~ollowing sections on the basis o~ example em~odiment~.
~in~e the audlt~ry canal often posse~ses smAll or large
bends and cUrves, i~ i~ normally no~ possible to hollow
out the l~terio~ ~rom the solid in the ne~essary way by
means of drillin~ or milling devices w~en produclng an
adaptive ~arpie~e or an otoplasty. The external contours
o~ ~n adaptl~e ea~piece or an otoplasty can normally be
produced ~ith a numerically ~ontrolled mllling cut~er and
thls could also be used satis~actorily. This will be
examin~d ln more detail ~elow.
~or example, Flg~ 13 shows such a ~e~hod. The contou~s of
the auditory canal 12 are d~termlned ln th~ manne~
described ln the cont~x~ o ~g. 3 and later in Fi~. 4 up
to produat~on and stor~ge o~ a three-dimenslonal comput~r
model o~ the otoplas~y or ~he adaptive earpie~e in the
data bas~ o~ in the memory 16, so ~hat a separate
descriptlon 1J not necessary he~e.
:
.
17 ~7~8,~
Since, a~ already mentioned, it can be very di~lcult to
produce an otoplasty or adapt~ve earpiace in one pi~ce,
it ls sugge~ted to divide ~he three-dimensional computer
model in~o several three dimensiona1 sub-~odels in
accordance with step D4a, whereby ~hese su~-model~ ar~
then stored in th~ data bases 2~b, ~c, 29d ... . One cf
thR parts 30b, 30c and 30d ... is then produced ~rom a
material block by mean~ o~ a comp~ter-co~trolled milliny
and/or grinding device in accordan~e with s~eps D~b, D4c
and ~4d ... . Synthetic resin ~locks are used here, for
example, Wh~ ah are approximately the s~me s1~e as the
part to he produced. In this method, both ~he internal
and exkernal contours oP the indivldual part~ o~ an
otoplasty or adaptive earpiece are thus produ~ed by
compu~er-controlled manufacturing methods. These parts
then result in the ~iniched adaptive earpiece via step
~)~e. In this context, it mus~ be men~oned that there are
v~riou~ possi~ tles ~o~ ~oining toge~her these
individu~l parts. For axample, one mlght provlde p~g3 and
peg holes or pro~ecting edges or shoulders at which the
individual par~ can be joinr~d ~o ~orm a whole and ~hen
bonded With ~ach other by gluein~, we}ding,
polymerization or ~lmil~r. Equally, i~ is pos~ible to
provide threaded bores ~n ~ome parts and bores ~or scr~ws
in other parts so tha~ the individual paxts can be ioi~ed
to~ether by screwing. ~hls would have the advanta~e that
the device could also be taken apa~t ~or repalrs.
how~ another me~hod of thi~ kind in co~junc~ion
with Flgs. 15 to 17.
Tnitially, as in Fig. 3 or 4 and Fig. 13, the dimensi~ns
of the auditory canal are recorded and then stored in a
d~ta memory or ln the data base 16 a~ a three-dimensional
compu~er model o~ ~he otoplasty.
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~ ' .
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18
In thi~ method, a further data ~ase 31 is used in which
prefabri~ated raw plastic blocks, as shown in Fig. 17
with 36a and 36b, are stored. These plastic blocXs, which
~ay correspond to two or more parts o~ an o~oplasty or
the housln~ o~ an in-the-ear hearing aid for example,
already contaln some o~ ~he chambers intended for
componen~s/ functions. ~n process step D5a, the da~a is
co~bined .rom the data bases 16 and 32 BO that the
corresponding posltions and dimenslon~ ~or produc~lon of
an otoplasty ~rom the prefab~icated plastic blocks ean be
optimized. Thi~ optim$zed data 1 then stored in memory
3~, which may also be part of the data base.
The data ~ontained in this m2mory is then used in step ....
D5b to pxoduce the f$nal shape of ~he otoplasty by
machine millin~ or grlnding, i..e. generally by material
removal ~rom the outer side until the prede~ined and
previously ~e~ermlned exte~nal contours o~ the otoplasty
have been ~chie~ed. ThiS is shown in Fig. 15, ~or.
example, where the part~ 34a and 34b are produced ~rom
bl~cks 33a ~d 33b.
The f1nished pArts 35a and 35b ln accordance wlth Fig.
are then produce~ by machinin~ ~rom the pre~abricated
bloc~s, whic~ already conta~n tne ~arious cavities ~or
the hearing aid and whl~h are shown in 36a and 36b ln
Fig. 1~7 .
~Ithough ths uso of drilllng or mill1ng dev~ces with
nu~e~icallv controlled machines might initially suggest
itsel~ for tne ~ubtrac~lve method, use of a so-called
Eximer laser operating in the ultravi~let range would
also be o~ par~icular advanta~e her~ since thl~ would
per~it removal o~ ~aterial ~rom the plastic ~lo~k or the
,: .
, ~
- 19 2~)~6~2
plastic or synthetic resin blocks ~ith h~gh preci~lon,
a I lowing e~en highly complex a~ernal or internal shapes
or sur~aces ~o ~e producPd without difficulty.
This method is therefore partlcula~ly ~ui~able for use of
thi~ subtractlve methad.
Although a number o~ methods for manu~acture o~
otoplastie~ or adap~ive earpieces have been described up
to now, st~rt~ng ~rom ~he contou~ dimensions determincd
erom the au~itory canal up to computer representation of
the three-dimen~ional o~opla~ty or adaptive earpiec~,
~his data and its conver~ion lnto two-dimensional cross-
sections or three-dimensional path curves can ~lso~
conceivably be used as 2 basis ~or other manu~acturing
method3 which thus also lie withln the scope o~ ~his
invention and should not b~ ex~lud~d.
