PROCESS AND DEVICE FOR TRACING AN ULTRASOUND FIELD

PROCEDE ET DISPOSITIF PERMETTANT DE BALAYER UN CHAMP ULTRASONORE

English Abstract

The invention refers to a process and a deviee to scan
an ultrasound field. The methods known up to now require a
large number of transducers in order to be able to record
the non-transmitted ultrasound waves from all directions.
In accordance with this invention, the number of ultra-
sound transducers is reduced to one or to very few by the
waves coming from different directions being subjected to
different measures to lengthen their paths.

French Abstract

L'invention concerne un procédé et un dispositif qui permettent de balayer un champ ultrasonore (21). Les méthodes utilisées jusqu'à maintenant requéraient une pluralité de transducteurs pour pouvoir capter les ondes ultrasonores non émises provenant de toutes les directions. Selon la présente invention, le nombre de transducteurs (22) est ramené à un ou à un nombre restreint, du fait que les ondes (21) provenant de différentes directions sont soumises à divers processus (23a-h) visant à en prolonger le trajet.

Claims

Claims
1. Process for the local scanning of an ultrasound field
existing in a medium at a specific time by means of a
transducer (5; 22; 32)
c h a r a c t e r i z e d b y t h e f a c t
that the ultrasound waves exiting the medium (2, 21,
31) are subjected to measures which increase their
sound propagation times from their exit areas on and
are then fed to the transducer (5; 22; 32).
2. Device to implement the process under Claim 1
c h a r a c t e r i z e d b y t h e f a c t
that mirrors (3, 4) are located at the points of the
ultrasound field which are to be scanned, these mir-
rors being distributed and oriented so that the ultra-
sound waves load the transducer (5) with different
sound propagation times via the mirrors (3, 4).
3. Device to implement the process under Claim 1
c h a r a c t e r i z e d b y t h e f a c t
that the transducer (22, 32) is connected with the
points of the ultrasound field which are to be scanned
by means of waveguides (a, ... h); 36, 34) having
different sound propagation times.

4. Device in accordance with Claim 3
c h a r a c t e r i z e d b y t h e f a c t
that the ultrasound waves to the points to be scanned
can be fed to the waveguides (a, ... h; 36, 34) by
means of collection devices (23).
5. Device in accordance with Claim 4
c h a r a c t e r i z e d b y t h e f a c t
that waveguide sections (36) of the same length are
connected with the collection devices and that the
ends of the waveguide sections (36) facing away from
the collection devices are connected to a common wave-
guide (34), one end of which loads the transducer
(32), at different longitudinal positions.
6. Device in accordance with Claims 3 to 5
c h a r a c t e r i z e d b y t h e f a c t
that waveguides (a, ... h; 36) contain liquid.
7. Device in accordance with Claims 3 to 5
c h a r a c t e r i z e d b y t h e f a c t
that waveguides (a, ... h; 36, 34) are made from a
solid material.
8. Device in accordance with Claims 2 to 7
c h a r a c t e r i z e d b y t h e f a c t
that further transducers - analogously to the trans-
ducer (5; 22; 32) - are connected to the ultrasound
field.

Description

Translation
21 88539
Sonident Company
under Liechtenstein Law
"Process and Device to Scan
an Ultrasound Field~
The invention refers to a process and a device to scan
an ultrasound field.
The scanning of ultrasound fields, for example as they
are [Translator: sic] used to verify the efficiency of
ultrasound fields or in devices to recognize surfaces and
surface-near structures of objects, has been carried out
up to now by means of transducers, which convert the
ultrasound waves sent back by the object to be measured
into electric signals and forward them to be evaluated.
Since the intensity of the ultrasound waves emitted or
back-scattered and reflected respectively varies depending
on the efficiency of the ultrasound source or on the
structure of the object to be studied, it is necessary to
use numerous transducers in order to be able to record the
waves returned in all directions. It has become clear that
a circular arrangement of a large number of transducers,
circa 250 with a diameter of 1 mm, allows for adequa-l,e
measurement of the ultrasound waves emitted or sent back
as the case may be.

2 21 88539
The large number of transducers necessary with t;he
known devices makes it complicated and expensive to
arrange them, so that on this basis mass production of
these devices to scan ultrasound fields is unsuitable.
Therefore the goal of the invention is to make it
possible to reduce the number of transducers used.
Based on the invention it is proposed to proceed in
accordance with the main claim. As a result the ultrasound
waves have different dimensions, their sound propagation
times are subject to measures to increase them, and the
sound waves, whether produced originally in the medium or
reflected or collected dispersed over various exit points
and then fed one by one to a single or very few trans-
ducers on paths of varying lengths. In this proces~ use is
made of the fact that it is possible in the ultrasound
field to have the sound waves arrive one by one temporally
at a single transducer or at very few transducers by mak-
ing use of different paths which are forced on the sound
waves from different directions and increase their sound
propagation times.
The number of transducers can be reduced considerably
in this way.
The path of the sound waves coming from the individual
directions can be increased in different ways. The ultra-
sound waves coming from different directions can be picked
up by a set of mirrors arranged at different distances and

2 1 8853~
at different places with respect to the medium or an
object respectively which emits them, this picking-up
being done in such a way that the waves have to travel
sound propagation times of different lengths to a single
or very few transducers. Another method is that a trans-
ducer is connected with the points to be scanned in the
ultrasound field via waveguides having different sound
propagation times.
The devices to implement the process using a mirror
arrangement consist of mirrors located in each case oppo-
site to the points to be scanned in the ultrasound field
and distributed and oriented so that the ultrasound waves
load the transducer with different sound propagation times
via the mirrors. Where waveguides are used, the ultrasound
waves at the points to be scanned are fed into the wave-
guides via collection devices and fed to one or more trans-
ducers for purposes of evaluation. The different sound
propagation times can be achieved either with similar wave-
guides of different lengths or with~waveguides of the same
length having different sound propagation times per time
unit. Waveguides with different sound propagation times
can also be achieved by first feeding the ultrasound waves
into waveguides of the same length which are then fed one
by one to a common channel. Surprisingly, it has been
shown that the mirrors or waveguides can be placed in a
liquid medium. The waveguides can also be arranged in a
solid material.

2 1 88539
be obtained by first feeding the ultrasound waves into
waveguides of the same length which are then fed on after
the other to a common channel. Surprisingly, it has been
shown that the mirrors or waveguides can be placed in a
liquid medium. The waveguides can also be arranged in a
solid material.
The drawings illustrated devices which can be imple-
mented with the inventive process. They illustrate as
follows:
Fig. 1 a device in which the increase in path is
achieved by means of a set of mirrors,
Fig. 2 a diagrammatic presentation of waveguides with
different lengths,
Fig. 3 a modification of the device illustrated in Fig.
2.
Fig. 1 illustrates the increase in the path of ultra-
sound waves by means of a set of differently arranged
mirrors. Reference number 1 designates an ultrasound
transmitter. The waves emitted by transmitter 1 strike a
plate 2 made of glass, which, for example can also be
equipped with an object. The waves coming from the indi-
vidual points on the plate or the object respectively are
directed from the base plate to the mirrors 3 and 4 and
are reflected from there one after another to the trans-
ducer 5. Consequently, the waves move from the transmitter
1 via the plate 2 and the mirror 3
Revised page

21 88539
Fig. 2 illustrates the use of waveguides. Ultrasound
waves of whatever origin radiating from the medium 21,
which can be the base plate for some object for example,
are directed to collection devices 23 located on the
medium 21 and, therefore, fed to the waveguides a to h
connected to them. These waveguides are of varying lengths
and have different sound propagation times as a result. As
is clear from the drawing, a is the shortest and h the
longest waveguide. It has become evident that the wave-
guides should differ in length by preferably 1 m in deter-
mining fingerprints. Therefore, waveguide b is 1 m longer
than a and c is 1 m longer than b and so on. All wave-
guides discharge into the transducer 22. The difference in
the waveguides of about 1 m is sufficient in the case of
the application mentioned to direct, in a differentiated
manner, the waves coming from the individual directions to
the transducer 22, which then forwards the appropriate
signals. In this way the waves sent back in different
directions are evaluated separately from one another. The
difference in length of the individual waveguides is to be
adjusted to the different objects to be recorded in each
case. In place of the arrangement with waveguides of dif-
ferent lengths, waveguides of the same length may be util-
ized which have different sound propagation times per time
unit. These different sound propagation times can also be
achieved through waveguides with thicker cross-sections or
waveguides made of different materials.
Fig. 3 illustrates a modification of Fig. 2. In it the
waves emitted by the medium 31 are fed to waveguides 36 of
the same length via collection devices (33) arranged in

6 21 8853q
different directions. The waveguides 36 discharge one by
one into a common waveguide 34, which is connected to the
transducer 32. The distance between the discharge points
35 of the individual waveguides 36 is such that the sig-
nals from the individual waveguides 36 reach the trans-
ducer 32 separated from one another and one after another
for purposes of forwarding the appropriate signals.
The designs in Figures 1, 2 , and 3 can be arranged in
a liquid, e.g. water.
It has become evident that, based on Figures 2 and 3,
the waveguides can be made of tubes filled with liquid or
of a sleeve of some kind or of a solid material, such as
glass or metal.
- Patent Claims -