WO2004106968A1

WO2004106968A1 - Material detector device

Info

Publication number: WO2004106968A1
Application number: PCT/CH2004/000275
Authority: WO
Inventors: Siegfried Stauber
Original assignee: Siegfried Stauber
Priority date: 2003-05-28
Filing date: 2004-05-06
Publication date: 2004-12-09
Also published as: DE10329335A1; DE10329335B4; TW200510713A; TWI336780B; CH696893A5

Abstract

The invention relates to a material detector device (1) which is provided with a search antenna polarisation instrument comprising: a rotatable body (3) which contains a magnetic disk (23) and is used to adjust the polarisation angle; a base body (5) which is connected to the rotatable body (3) and contains a resonance disk (25) forming an antenna, one side (26) of said resonance disk being oriented towards the magnetic disk (23); an insulating layer (28) which is adjacent to the other side (27) of the resonance disk (25); a Mumetall® layer (29) which is adjacent to the insulating layer, the resonance disk (25) and the Mumetall® layer (29) forming a capacitor (30); and a printed circuit board (14) which comprises electronic elements and is electrically connected to the capacitor (30). The frequency and/or the amplitude of the signal received by the detected material can be determined by said printed circuit board.

Description

Material detecting means

The invention relates to a material detector device.

In an article that was received in 1934, Wüst and Wimmer report on novel vibrations of the wavelength in the vicinity of organic and inorganic substances as well as biological objects. However, the results were relatively difficult to reproduce and inaccurate.

So-called magnetometers are known for detecting iron. Metal detectors or so-called metal detectors are also available on the market. The metal detectors available on the market usually work with coils, and these send out a signal in a certain direction and then measure the returning, reflected signal. However, the devices mentioned have the disadvantage that they must be held directly over the object sought. With these devices, location from a greater distance is not possible. But even if the devices are held in the immediate vicinity next to instead of on or over the searched object, they do not show the desired object or the searched material.

The invention has for its object to provide a material detector device which is more versatile and in particular is able to find the material or object sought even over a greater distance.

This object is achieved according to the invention by a material detector device with the features of patent claim 1. Advantageous further developments are the subject of the dependent claims.

With the help of the (parallel) magnetically flooded capacitor and the soft magnetic electrodes used, the desired material can be scanned in terms of its specific width and length ratios, so that the dimensions of the material can be determined. With the device according to the invention, it is possible to determine the position of the material sought even over a greater distance and to detect the radiation between electrically conductive, magnetic resonances. to measure nanzkörpem. The parts of the search antenna polarization instrument specified in claim 1 form a resonant resonant circuit, the resonant disc forming the antenna representing the inductance L of the resonant circuit. Provided that forming the antenna resonant disc of ferromagnetic material is prepared (such as dynamo sheet, Mumetall ^®, permalloy, carbonyl iron or other soft magnetic material), the aforementioned increases inductance L of the resonance disc by the permeability as a material constant. This enables the resonant circuit to have a small capacitance for tuning. This makes it easier to eliminate interference frequencies and to maintain the resonance frequency.

According to a development of the invention, the rotatable body forms the upper part of the search antenna polarization instrument and has a spirit level, preferably in the form of a circular bubble, on its upper side for vertical alignment of the instrument. In this way, on the one hand, the vertical alignment of the search antenna polarization instrument can be established or checked, on the other hand, the searched polarization angle can be easily determined and read.

According to another development of the invention are preferably formed two pole resonance disc, the insulating layer and the mu-metal ^® layer by means of these parts penetrating central screw, preferably a hollow screw with an internal tuning screw fastened to the printed circuit board. As a result, the above-mentioned parts are securely held on the printed circuit board and directly attached to it, so that the device according to the invention can be of extremely compact construction.

The insulating layer is advantageously made of polycarbonate and the Metal ^® layer is in the form of a magnetic lens. Polycarbonate is a good insulator with a comparatively low weight.

According to a preferred development, the resonance disc is a transmitting and receiving antenna, by means of which a transit time measurement can be carried out, for example, for determining the distance, by superimposing a pulse on the signal emitted by the resonance disc and measuring the transit time of the pulse, i.e. the time until the pulse returns from the found material again at the sound disk has arrived. The resonance disc is thus able to transmit and receive electrical signals in the sense of a double effect.

According to a particularly preferred embodiment of the invention, the resonance disk is hair-shaped or tubular, rectangular, rectangular-arch-shaped, lenticular, partially circular, arch-shaped, with or without one or more notches or from a combination of the aforementioned shapes and preferably has a bore. This means that a large number of resonance discs are available for practical applications, so that a suitable resonance disc can be selected for each application.

According to a development of the invention, the one or more notches are shaped like a circular section.

The search antenna polarization instrument advantageously has a light-emitting diode, a connection for headphones or an electrical measuring device and / or a built-in loudspeaker. This allows the signals determined to be displayed particularly easily, and thus perceived optically or acoustically.

According to a particularly preferred embodiment of the invention, the signal received by the found material is designed and polarized in the form of a rotary shaft, preferably an edge rotary shaft, center rotary shaft or dimensional rotary shaft, preferably the diameter of the resonance disc or the wavelength of the signal or its fraction corresponds to π and ^3, π ^3/2 or π ^3/4. The diameter of the resonance disc can thus correspond to the wavelength of the signal received by the material found. However, it is also possible for the diameter of the resonance disc to correspond to straight fractions of the wavelength of this signal. Thereafter, the diameter of the resonance disc depends on the material sought or found and can be easily determined using the aforementioned dimensioning rule.

Other developments of the subject matter of the invention are specified in the dependent claims. Exemplary embodiments of the subject matter of the invention are explained in more detail below with reference to the drawing, all of the features described and / or illustrated individually or in any combination forming the subject matter of the present invention, regardless of how they are summarized in the claims or their relationship. Show it:

1 shows a schematic front view of a material detector device;

FIG. 2 shows a schematic side view of the material detector device according to FIG. 1;

FIG. 3 shows a schematic top view of the material detector device according to FIG. 1;

4 shows a schematic, partial vertical section through the upper part of the material detector device;

5 - 17 are schematic representations of a resonance disk of the material detector device, predominantly each in a top view;

18 shows a resonance disk in the form of a converging lens;

19 is a schematic front view of a resonance disk called pinch;

20 shows a section through the resonance disc according to FIG. 19;

Fig. 21 is a schematic plan view of the resonance disk called pinch;

22 shows a schematic, partial vertical section through the upper part of the material detector device according to another embodiment; and

23 shows a circuit diagram of a series resonant circuit used in the material detector device.

1 to 3 different views of a material detector device 1 are shown schematically. In detail, the material detector device 1 is shown in FIG. 1 in a front view, in FIG. 2 in a side view and in FIG. 3 in a top view.

The material detector device 1 has a search antenna polarization instrument 2. This search antenna polarization instrument 2 has a rotatable body 3, which forms the upper part 4 of the search antenna polarization instrument. The Rotatable body 3 sits on a base body 5. Rotatable body 3 and base body 5 sit concentrically on one another and have a common longitudinal axis 6.

On its upper side 7, the rotatable body 3 has a spirit level 8 which, according to a particularly preferred embodiment, is in the form of a circular bubble. The bladder 9 is shown in a side view in FIGS. 1 and 2 and in a top view in FIG. 3. The spirit level 8 is used in particular for the vertical alignment of the instrument 2, in which the longitudinal axis 6 is perpendicular to a floor, not shown in detail.

The rotatable body 3 also has a pointed downward, i.e. Mark 10 tapering toward base body 5, the lower tip of which ends at lower edge 11 of rotatable body 3. On the upper edge 12 of the base body 5 there is a degree scale 13, that is to say as it were opposite the tip of the marking 10. In FIG. 1 the degree scale 13 at the height of the longitudinal axis 6 shows the value 0 degrees. Towards the left in FIG. 1, the degree scale 13 has a division between 0 and +90 degrees, on the right in FIG. 1 accordingly from 0 degrees to -90 degrees. The left half in FIG. 1 can also be seen in the side view according to FIG. 2 of the material detector device 1. It is clear that the connecting line between the value +90 degrees on the degree scale 13 and the longitudinal axis 6 forms a right angle with the connecting line between the value 0 degrees on the degree scale 13 and the longitudinal axis 6.

The base body 5 also has a printed circuit board 14, which is only indicated by dash-dotted lines in FIG. 2, with a plurality of electronic elements 15 which are likewise only indicated by dash-dotted lines. At its lower end in FIG. 2, the printed circuit board 14 has a plurality of brackets 16, indicated by dash-dotted lines, which are connected to a 9 volt -Battery 17 are in contact. The battery 17 has a housing (not shown in detail), preferably made of nickel, and is inserted from the outside into a recess 18 in the base body 5. As indicated in FIGS. 2 and 3, the outer end of the battery 17 projects outwards beyond the jacket-shaped outer contour 19 of the base body 5.

On the outer contour 19 there is also a light-emitting diode 20 and a connection 21, for example for headphones or an electrical measuring device (not shown). Furthermore, a loudspeaker can be built into the base body (not shown). Light-emitting diode 20 and connection 21 and possibly speakers connected to the printed circuit board 14 and are located on that side of the printed circuit board which also has the aforementioned electronic elements 15. As illustrated in FIG. 3, the light-emitting diode 20 and the connection 21 lie on the side of the base body 5 opposite the battery 17.

The more precise structure of the search antenna polarization instrument 2 can be seen in a partial vertical section from FIG. 4.

The rotatable body 3 has an inner shoulder 22 for receiving a magnetic disk 23, which is, for example, a plastoferrite magnet. With the aid of the magnetic disk 23, the polarization angle 24 can be set by rotating the rotatable body 3 and read off on the degree scale 13.

The base body 5 of the search antenna polarization instrument 2 has a resonance disk 25 forming an antenna, one side 26 of which, in FIG. 4 this is the upper side, is arranged facing the magnetic disk 23 of the rotatable body 3. Furthermore, the base body has an insulating layer 28 adjoining the opposite, other side 27 of the resonance disk 25, which is preferably made of polycarbonate. In addition, the base body 5 has a Mumetall ^® layer 29 which adjoins the insulating layer 28 and which is preferably designed in the form of a so-called magnetic lens. Rotationally symmetrical magnetic fields, such as z. B. generated by current-carrying coils, act on charged particles, such as. B. electrons or ions that remain near the field axis, focusing. In order to be able to build lens fields that are as strong as possible, the field is concentrated in a small space with the help of pole shoes using the magnetic lens. Magnetic lenses of this type are also called pole shoe lenses. The Mumetall ^® layer 29 is a permalloy alloy made of 76% nickel, 17% iron, 5% copper, 2% chromium and at most 0.1% carbon.

According to the invention form resonant disc 26 and Mumetall ^® layer 29 a capacitor 30, which electrically having the electronic elements 15 printed circuit board 14, respectively. The electronic elements 15 are omitted in FIG. 4 for the sake of simplicity. With the aid of the aforementioned components, it is possible to receive the frequency and / or amplitude of the piece of material found or sought (this is denoted in FIG. 3 by the reference symbol 46) To determine the signal in more detail and thereby determine the type and location and, if necessary, also the size of the piece of material.

The preferably two-pole formed resonance plate 25, the insulating layer 28 and the mu-metal ^® layer 29 are centrally by a screw 31, which is designed as a hollow screw, penetrated and fixed by a nut 32 on a L-shaped bracket 33 which receives the printed circuit board 14 and is electrically connected to it. Between the holder 33 and the insulating layer 28 there is also a rivet sleeve 34. Between the screw 31 and the cylindrical inner wall of the rivet sleeve 34 there is also a teflon sleeve 35. In addition, a teflon ring 36 extends between the nut 32 and the holder 33. As shown in FIG 4, the Teflon sleeve 35 extends at least partially through the insulating layer 28 and through the Teflon ring 36. In this respect, the Teflon ring could also form a type of flange of the Teflon sleeve and be formed in one piece with the latter. In addition, a so-called tuning screw 37 is screwed into the screw 31 from below, which is used to fine-tune the emitted and / or received signals.

According to the invention, the resonance disk 25 is a transmitting and receiving antenna, by means of which the distance, i.e. To determine the distance between the material detector device 1 and the found piece of material 46 shown schematically in FIG. 3, a transit time measurement can be carried out by superimposing a pulse on the signal emitted by the resonance disc 25 and the transit time of the pulse, i.e. the time is measured until the impulse coming back from the found material has reached the resonance disc again.

Individual embodiments of the resonance disk 25 are predominantly shown in a top view in FIGS. 5 to 17. The resonance disk is preferably made of pure nickel. It is pointed out that, in particular in FIGS. 5 to 8, only the left half which is mirrored on a longitudinal axis 47 of the resonance disc 25 is shown in solid lines. The right, second half of these resonance disks is only shown in dashed lines in FIGS. 5 and 8. Ultimately, all other embodiments of the resonance disc, with the exception of the resonance discs shown in FIGS. 13, 16 and 17, and the resonance disc shown in FIGS. 19 to 21 can also be provided with a second half mirrored on the longitudinal axis. In Fig. 5 the resonance disc is hair-shaped or L-shaped. FIG. 6 shows a tubular design, while in FIG. 7 a rectangular resonance disc 25 is shown. It is clear that in relation to the shapes shown in FIGS. 5 and 6, the term resonance disk is not to be understood strictly literally and is to be interpreted to the extent that the shapes shown in the figures are also subsumed under it. In Fig. 6 the resonance disc is shown in a side or front view. In this embodiment, the base surface 48 is a circular disc and the tube 49 has a cylindrical cross section.

8 shows a rectangular-arched configuration of the resonance disk 25. 9 and 10, the upper flat 38 with the right boundary line 39 of the resonance disk 25 in FIG. 9 forms an angle 40 of approximately 45 ° and in FIG. 10 an angle 40 of approximately 30 °. 11 to 13, the resonance disks 25 are approximately semi-circular, the angle 43 enclosed by the two legs 41 and 42 of each resonance disk 25 being 180 ° in the case of FIG. 11, approximately 171 ° in the case of FIG. 12 and 13 is approximately 189 °.

14 and 15, the resonance disks 25 are of arcuate design, a 90 ° bend 44 being provided in the embodiment shown in FIG. 14 and two 90 ° bends 44 being provided in FIG.

Furthermore, the resonance disc can have one or more notches 45. 16 and 17 there are two notches 45 lying diagonally opposite one another and in FIG. 17 four notches 45 lying opposite each other in pairs. The resonance disk preferably has a central bore 64. However, it is also possible for the resonance disk to have only one notch 45 or to be formed from a combination of the aforementioned or other shapes. According to a particularly preferred embodiment, the notch or the plurality of notches is shaped like a circular section.

Further embodiments of the resonance disk are shown in FIGS. 18 to 21. 18 shows a plan view of a resonance disk 25 in the form of a so-called converging lens. For the flattening angle shown in Fig. 18! the relationship applies:

α = 29.7177 °.

The resonance disk 25 shown in FIGS. 19 to 21 is called pinch. It is roughly like the resonance disk shown in FIG. 12 including the right, mirrored half, not shown in FIG. 12, but is substantially thicker than that.

FIG. 19 shows a schematic front view, FIG. 20 shows a section through the resonance disc according to FIG. 19 and FIG. 21 shows a top view of such a resonance disc. 19, the resonance disk 25 has the diameter D and the thickness D / 2. 20 illustrates an insulator 50 and electrical conductors 51, 52, the latter of which forms the outer surface 53 of the resonance disk. 21 illustrates that the resonance disk 25, which is designed as a so-called pinch, has a notch 45.

According to an embodiment not shown, it is also possible to design the resonance disk in the form of a cone or a pyramid. It is clear that the chosen term "resonance disc" is to be interpreted in such a way that it also includes such antenna shapes. Such a cone can be formed, for example, by forming a tip cone above the resonance disc, for example according to FIGS. 11 to 13 and 16 and 17. It is clear that in this case the rotatable body 3 is designed in such a way that such antenna shapes can be accommodated therein.

According to a particularly preferred embodiment, the signal coming back or received from the material found is in the form of a rotary shaft, preferably an edge rotary shaft, center rotary shaft or dimensional rotary shaft. With the so-called edge rotation shaft, the signal goes to the edge of the material sought, with the so-called center rotation shaft to its center, and with the so-called dimension rotation shaft, it goes back to the material searched for so that its entire surface reflects the rotation shaft. Assuming that in FIG. 5 the length of the resonance disc is L and the radius r and further assuming that in FIGS. 11, 12 and 13 r the radius and U are the circumference of the respective resonance disc 25, is preferably

at the edge wave

at the center wave

at the dimensional wave

According to an embodiment not shown in more detail, the resonance disk is designed in the form of a cone or a pyramid, with α for the cone angle or the pyramid surface or edge angle

with an edge rotary shaft sin α = 1 / π

with a center rotary shaft tg α = ^' 1 / π

applies. The particular advantage of the pinch, cone and pyramid antenna shapes is that no tuning capacitor, i.e. no variable capacitor, is necessary. However, the dimensions and the cone-pyramid angle α according to the last two relationships must be strictly observed.

In a preferred embodiment of the invention, the diameter of the resonance disk 25 corresponds to the wavelength of the signal or its fraction. This diameter is preferably ³ π, π ^3/2 or π ^3/4.

According to a particularly preferred embodiment, there is a very specific resonance disk 25, which could also be called a disk antenna, with the corresponding diameter or circumference for the corresponding frequency or wavelength for each material sought. With reference to FIG. 3, a piece of material 46 to be found or located, for example made of metal, is shown in front of the material detector device 1 at a certain distance, which is shown particularly small for drawing reasons. The piece of material is at an angle of 0 °. In such a case, a minimum signal is obtained with the antenna in the form of the resonance disc. A similar value is obtained with a 90 ° arrangement. By contrast, a maximum signal is obtained when the piece of material 46 is arranged at 45 ° (shown in broken lines in FIG. 3). As mentioned, the rotatable body 3 of the instrument 2 is rotatable for setting the polarization angle 24. To determine the signal, a headphone or an electrical measuring device can be connected to the connection 21 in order to directly indicate the frequency and amplitude of the received signal and, if appropriate, the position of the material sought via the value of the direct current. The printed circuit board preferably has an amplifier circuit and is used in particular to measure the wavelength and the frequencies of the received signals. The resonance frequencies are usually in the audible range between 20 and 20,000 Hz. However, resonance frequencies occurring outside the audible range can also be determined with the aid of appropriate display devices.

22 shows a schematic, partial vertical section through the upper part of the material detector device according to another embodiment.

According to this embodiment, three magnetic plates 54 are provided, a polycarbonate layer 55 being located below the upper magnetic plate 54. This is followed by the resonance disk 25 at the bottom. A further polycarbonate layer 55 is located on the central magnetic plate 54. In FIG. 22, below the central magnetic plate 54, there is a polycarbonate plate 56 at a distance from the latter. Below the latter there is a further resonance disk 25, which is designed as a position and polarization angle resonator. A polycarbonate layer 55 is again located above the lower magnetic plate 54. As in the embodiment shown in FIG. 4, the screw 31 is again designed as a hollow screw and is surrounded by the Teflon sleeve 35. However, the upper resonance disk 25 is in direct contact with the screw 31. In the lower part of the screw 31, the rivet sleeve 34 is located on the outside on the Teflon sleeve 35. The radiation losses are minimized with the aid of the three magnetic disks 54 described above. The entire arrangement ultimately preferably forms a package with self-adhesive magnetic plates and polycarbonate layers. The total diameter 57 in this arrangement is preferably 31 mm, namely exactly π ³ mm.

A basic circuit 58 in the form of a series resonant circuit is shown schematically in FIG. The resonance disk 25 is connected to a first capacitor 59 with 50 to 300 pF, which can also be bridged by an adjustable second capacitor 60 with 0 to 50 pF. The output of both capacitors is connected to a first diode 61 and to a second diode 62. The former is connected on its other side to an amplifier, not shown, the second is connected to a resistor 63 with 200 kΩ. Resistor 63 is also connected to a 9 volt DC power source. The basic circuit shown in Fig. 23 operates with 0 to 8 volts DC. The diodes 61, 62 can be designed as an impedance converter. Instead of the diodes mentioned, it is also possible to use signal field effect transistors for direct or alternating current. The basic circuit mentioned is suitable for alternating current and direct current signals.

When operating the material detector device described above, the following four influencing variables exist:

1. the static earth magnetic field has an influence on the direct current signal;

2. The static gravity of the earth, called gravitation, also has an influence on the direct current signal;

3. the electromagnetic waves affect the AC signal;

4. The magnetic double wave, also called Zenek wave, also influences the AC signal.

When using the material detector device, double waves are usually transmitted and received.

The polarization setting and measurement can be done mechanically by swiveling, tilting, rotating the material detector device or magnetically by a static, magnetic interference field or electrically directly by means of the capacitor (0 - 8 V DC voltage), e.g. B. with the help of a coil, by applying a DC voltage of 0 to 8 volts to the coil. The resonance disk is, for example, made of a soft magnetic material, preferably pure iron, pure nickel and their alloys. The resonance disk can be made of any metal and / or a semiconductor or piezoelectric material. According to an embodiment not shown, two mutually opposite magnetic plates are arranged outside the rotatable body of the search antenna polarization instrument, the static magnetic field of which is generated by a coil.

The initial polarization angle is set with a DC voltage between 0 and 8 volts (for an alloy, for example, 2.67 volts). The magnetic field of the resonance disk can be evaluated by means of a Hall or magnetic field sensor, for example manufactured by Philips under the name KMZ 10.

The procedure for measuring is explained in more detail below.

First, the material detector device 1 is held vertically with the aid of the spirit level 8 and the bubble 9. The polarization angle 24 is set to 0 "by rotating the rotatable body 3 such that the tip of the marking 10 meets the polarization angle 0 ° of the degree scale 13. The detector device is then rotated 360" in the vertical position in order to clarify at which angle of rotation (azimuth angle!) a signal can be obtained taking into account that a maximum signal is obtained when the resonance disc, also called a rotating antenna, takes an angle of 45 ^D to the piece of material being searched for and a minimal signal is then obtained, when the rotary antenna to the material piece takes an angle of 0 or 90 ". In the vertical position, as indicated in FIGS. 1 and 2, the detector device has an opening angle of 180 *, namely + or - 90", so that only from signals can be received at this opening angle.

The rotating antenna is then rotated again so far that the signal is minimal. In this rotary position, the detector device is tilted by 90 ° in the direction of the minimum signal in the horizontal plane and held in this position. A subsequent follow-up check can determine where the signal is minimal by rotating the detector device in different directions in the horizontal plane. According to a first variant, the position determination of a desired piece of material can be determined by cross bearing. If the detector device is correctly aligned, in this position there is only a minimal signal, the same measurement is carried out again from another location, so that the exact location of the piece of material or generally of the object sought can be determined by the so-called cross bearing.

According to a second variant, the position of the piece of material sought can also be determined by determining the angle and distance. The angle is determined in the manner described above; For the distance determination, as already indicated above, a transit time measurement is carried out by superimposing a pulse on the signal emitted by the rotary antenna, that is to say from the resonance disc, and by measuring the transit time of the pulse, namely the time which the pulse requires until it is received the desired piece of material is reflected back at the rotating antenna.

The resonance disks can also be designed as a so-called dipole, for example by placing two disks next to or on top of one another. This makes it possible to obtain a signal that is twice as strong. Furthermore, the printed circuit board 14 can be provided with potentiometers for setting a bias voltage on the capacitor electrodes of the material detector.

This creates a material detector device with which a sought-after material can be found even over a greater distance.

Claims

claims

Material detector device with a search antenna polarization instrument (2), which has:

(a) a rotatable body (3) having a magnetic disk (23) for adjusting the polarization angle (24),

(b) a base body (5) connected to the rotatable body (3), which has a resonance disk (25) forming an antenna, one side (26) of which is arranged facing the magnetic disk (23) of the rotatable body (3) to the other side (27) of the resonance plate (25) subsequent insulating layer (28), a to ^® to the latter subsequent mu-metal layer (29), said resonance plate (25) and Mumetal ^® layer (29) comprises a capacitor (30 ) and has a printed circuit board (14), which is electrically connected to the capacitor (30) and has electronic elements (15), by means of which the frequency and / or amplitude of the signal received by the material found can be determined.

Material detector device according to claim 1, characterized in that the rotatable body (3) forms the upper part (4) of the search antenna polarization instrument (2) and for vertical alignment of the instrument (2) on its upper side (7) a spirit level ( 8) preferably in the form of a circular bubble.

Material detector device according to claim 1 or 2, characterized in that the preferably bipolar resonance disc (25), the insulating layer (28) and the Mumetall ^® layer (29) by means of a central screw (31) penetrating these parts, preferably one Banjo bolt with inner adjustment screw (37) on which the printed circuit board (14) is attached.

4. Material detector device according to one of the preceding claims, characterized in that the insulating layer (28) made of polycarbonate and the Mumetall ^® layer (29) is designed in the form of a magnetic lens.

5. Material detector device according to one of the preceding claims, characterized in that the resonance disc (25) is a transmitting and receiving antenna, by means of which a time-of-flight measurement can be carried out for determining the distance, by superimposing a pulse on the signal emitted by the resonance disc (25) the duration of the pulse, ie the time is measured until the pulse coming back from the found material has reached the resonance disc (25) again.

6. Material detector device according to one of the preceding claims, characterized in that the resonance disc (25) hair or tube-shaped, rectangular, rectangular-arc-shaped, lenticular, part-circular, arc-shaped, with or without one or more notches (45) or from one Combination of the aforementioned shapes is formed and preferably has a bore (64).

7. Material detector device according to claim 6, characterized in that the one or more notches (45) are shaped like a circular section.

8. Material detector device according to one of the preceding claims, characterized in that the search antenna polarization instrument (2) preferably has a light-emitting diode (20), a connection (21) for headphones or an electrical measuring device and / or a built-in loudspeaker ,

9. Material detector device according to one of the preceding claims, characterized in that the received from the found material Signal in the form of a rotary shaft, preferably an edge rotary shaft, center rotary shaft or dimensional rotary shaft, is formed and polarized

10. Material detector device ηach claim 9, characterized in that the resonance disc (25) has a length (L) and a radius (r) and for the ratio radius / length (r / L)

at the edge wave

at the center wave

at the dimensional wave

applies.

11. Material detector device according to claim 9 or 10, characterized in that the resonance disc is in the form of a cone or a pyramid and for the ^' -, cone angle or the pyramid surface or edge angle ()

with an edge rotary shaft sin = 1 / π with a center rotary shaft tg α = 1 / π-.

applies

12. Material detector device according to one of claims 9 to 11, characterized in that the diameter of the resonance disc len length of the signal or its fraction and preferably 7t ³ , τ? l or 7rV4.

13. Material detector device according to one of the preceding claims, characterized in that the resonance disc (25) is made of a soft magnetic material, preferably Reϊneisen, Reiππiekel or their alloys.

14. Material detector device according to one of claims 1 to 12, characterized in that the resonance disc (25) is made of any metal and / or a semiconductor or piezoelectric material.

15. Material detector device according to one of the preceding claims, characterized in that outside of the rotatable body (3) of the search antenna polarization instrument (2) two mutually opposite magnetic plates are arranged, the static magnetic field of which is generated by a coil.

16. Material detector device according to one of the preceding claims, ^{'characterized} by, that the initial polarization angle with a DC voltage between 0 and 8 volts (z is an alloy. B. 2.67 volts) is set.

17. Material detector device according to one of the preceding claims, characterized in that the magnetic field of the resonance disc (25) can be evaluated by means of a Hall or magnetic field sensor.