KR960004557B1 - Magnetic image sensor using mateuchi effect - Google Patents

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Description

Magnetic Image Sensor Using Mateuchi Effect

1 is a schematic block diagram of a signal detection unit which is a main part of a coordinate input device according to the present invention.

2 is a principle diagram showing the concept of pulse voltage generation of a magnetic wire imparted with magnetization in the circumferential direction.

3A and 3B are timing diagrams of an alternating magnetic field and generated pulse voltage according to this principle, respectively.

4 is a conceptual diagram of a coordinate input device according to the present invention.

5 is a conceptual diagram of a basic configuration for explaining the operation of the coordinate detection which is another embodiment of the present invention.

6 is an operation explanatory diagram in which the U-turn bent magnetic wire rotates the magnetization in the circumferential direction by an external magnetic field.

7 is a configuration diagram for fixing the magnetic material on the substrate.

8 is a conceptual diagram of a high sensitivity sensor for measuring the vertical distance between the electromagnet and the magnetic wire pattern.

9 is a block diagram showing the overall configuration of a coordinate input device according to the present invention.

10 is a cross-sectional view of the coordinate detector showing the arrangement of the magnetic wires in the X and Y directions.

FIG. 11 is a characteristic curve diagram showing the relationship between the Mateuchi effect voltage occurring at adjacent wires and the distance from the center of each wire. FIG.

12 is a characteristic curve diagram showing the relationship between the distance and the voltage ratio detected on adjacent wires.

13 is a flowchart showing the coordinate point calculation procedure of the coordinate input device.

14 is a block diagram of a magnetic image sensor according to the present invention.

Fig. 15 is a conceptual diagram of a detection unit of this magnetic image sensor.

16 is a timing diagram of an excitation signal of the magnetic image sensor and an A-B detection signal.

The present invention relates to a magnetic image sensor using the Matechucci effect.

When a magnetization in the circumferential direction is applied to one magnetic wire and an alternating magnetic field is applied from the outside in the direction crossing the wire, a pulse voltage is generated at both ends of the wire. The so-called Mateuchi effect occurs. This effect is known, but there will be little application technology.

Coordinate input devices such as digitizers and handwriting characters are described in Japanese Patent Application Laid-Open No. 61 (1986) -70628, but the coordinate input device using the Mateuchi effect is not known. not.

In addition, magnetic image sensors detect magnetic information of multiple tracks, such as magnetic cards, and magnetic fields generated by magnetic bodies existing in bright phenomena. However, multi-channel gap magnetic head magnetoresistive element arrays and hall element arrays are used. Therefore, there is a disadvantage in that the cost is high, the detection circuit also requires multiple channels, and the circuit amount is large.

An object of the present invention is to provide a magnetic image sensor using the Mateuchi effect.

The magnetic image sensor using the Mateuchi effect of the present invention comprises at least one magnetic wire, means for imparting magnetization in the circumferential direction to the magnetic wire, and arranged along the longitudinal direction of the magnetic wire. Means for generating a plurality of alternating magnetic fields, a constant alternating current power supply, switching means for supplying currents from said static alternating current power supply one by one to said plurality of alternating magnetic field generating means in turn, and said magnetic wire and said alternating current Means for detecting a matew effect voltage generated between both ends of the magnetic wire by interaction between a magnetic field generating means and a static magnetic field to be detected, and the detected crystal of the matew effect voltage detected by the detecting means. Means for forming this detected magnetic field image from the modulated signal by the magnetic field.

Next, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a signal detection unit of the coordinate input device according to the present invention, and an alternating magnetic field is applied to the coordinate designator by the magnet for specifying the coordinates or the coordinate indicator 2 using the magnetic wire 1 as the coordinate detector. The DC bias circuit 4 is disposed so that a DC current flows through the magnetic wire 1 to impart magnetization in the circumferential direction. By connecting the DC bias circuit 4 to the magnetic wire 1, in order to prevent the impedance of both ends of the magnetic wire 1 from dropping and the generated pulse voltage from dropping, the AC wire is connected to at least one end of the magnetic wire 1. The high impedance circuit 3 is provided. In this way, the pulse voltage generated in the magnetic wire 1 is the voltage of P-Q at both ends of the magnetic wire 1, and the 2f component is detected using the double wave detection circuit 5. It is possible to use a general resonance circuit, a filter circuit or a synchronous detection circuit as the double frequency detection circuit 5. The control circuit 6 supplies an excitation current based on 1f to the coordinate specifying electromagnet 2, and also sends a control signal based on 2f to the distribution frequency detecting circuit 5 as necessary. .

The pulse voltage generation principle of FIG. 2 shows an embodiment in which an alternating magnetic field is applied to the magnetic wire 1 imparted with magnetization in the circumferential direction. As for the magnetization of the magnetic wire 1, a part of the circumferential magnetization which the magnetic wire 1 has by the alternating magnetic field which generate | occur | produces from the coordinate specification electromagnet 2 repeats inversion and return. At this time, the magnetic field and the pulse voltage of the electromagnet generated at both ends of the magnetic wire are shown in Figs. 3A and 3B. The number of inversions of magnetization changes depending on the combined value of the magnetic field generated from the electromagnet and the geomagnetism. The frequency component of the voltage generated across the magnetic wire is 1f, 2f, 2f,... It consists of the synthesis value of each frequency component of.

It can be seen that the 1f component fluctuates greatly by the alternating magnetic field. In addition, the 2f component has the same waveform as shown in FIG. 3b, and the fluctuation is less. Therefore, it is effective to detect the 2f component of the pulse voltage component generated in the magnetic wire, and the detection circuit 5 of FIG. 1 detects the 2f component.

As a method of imparting circumferential magnetization to the magnetic wire, a method of imparting magnetization by a magnetic field determined by the law of the right-hand screw by flowing a DC current through the magnetic wire is easy, and the DC bias circuit 4 is used for this purpose. do. Thus, the DC current amount can also be controlled. It is also possible to reduce the influence of external magnetic fields such as geomagnetism by increasing the current flowing through the magnetic wire.

4 shows a conceptual diagram as a coordinate input device in which the detector of FIG. 1 is arranged in the form of an XY matrix. A plurality of magnetic wires 1 are disposed in each of the X and Y directions for detecting the position of the coordinate designating electromagnet 2. In FIG. 4, only the voltage detecting section in the Y direction of the magnetic wire 1 is shown, but the same function is also provided in the X direction. The detection side termination circuit 7 includes a function of the AC high impedance circuit 3 of FIG. 1, a signal multiplex circuit for guiding pulse signals from the respective Y-directional magnetic wires 1 to the detection circuit in sequence; It has a double frequency detection circuit. In addition, the drive side termination circuit 8 includes a DC current bias circuit 4 in the case of FIG. 1 and an AC high impedance circuit 3 connected to the circuit 4 as necessary. The coordinate detection control circuit 9 not only excites the coordinate designating electromagnet 2, but also generates timing signals for controlling the double frequency detection circuit function and the multiplex circuit function. Their circuit configuration will be described later in more detail.

As described above, the coordinate input device for detecting the generated voltage at the circumferential magnetization reversal of the magnetic wire generated when the coordinate indicator excited by AC is brought close to the magnetic wire magnetized in the circumferential direction is wound around the magnetic wire which is the coordinate detecting body. Since a voltage is generated without the need for an etc., it is effective as a detection principle of a new coordinate input device. However, since voltages are generated at both ends of the magnetic wires, when a plurality of magnetic wires are arranged in an array for coordinate detection, both ends of the magnetic wires fall in distance and the signal is connected between both ends of the magnetic wires. A path is needed. When the ear environment is disposed in the outer frame portion, in addition to the coordinate detection signal originally generated by the magnetization rotation of the magnetic wire, the magnetic coil and the loop coil made by the ear environment combine with the external magnetic field to generate a signal. When the magnetic wire is thinned, it becomes larger than the voltage component at the time of rotation of the circumferential magnetization of the magnetic wire to be detected, which causes a decrease in the S / N ratio of the signal for coordinate detection.

As a method of reducing the electromagnetic coupling by the loop coil formed by the coordinate detector and the return path, a method of reducing the area of the rope coil is effective. Thereby, the method of making noise in the detection voltage by electromagnetic coupling small is possible. In addition, due to the detection principle of the magnetized magnetic wire in the circumferential direction, the same magnetic wire is used as the ear environment so that the signal of the magnetization reversal is added with the voltage generated by the magnetic wires of the back and the return paths. The detection voltage can be obtained twice as long as the path is made of magnetic wires and the path is made of ordinary conductors. An embodiment for this purpose will be described with reference to FIGS. 5 and 6.

In Fig. 5, the magnetic wire 1 of the outward path and the magnetic wire 1 'of the return path are bent U turns at the U turn fixing point 1R. The circuit for imparting circumferential magnetization to both wires is the bias circuit 4. In the magnetic wire, the coordinate indicator 2 excited by the AC signal source 2S gives an AC magnetic field. FIG. 6 shows the operation principle of the coordinate detector. The magnetization in the circumferential direction shown in FIG. 6 is generated inside the magnetic wire 1 and the magnetic wire 1 'of the return path by the bias current indicated by the arrow. have. When the magnetization direction of the wire is rotated by the magnetic field generated by the coordinate indicator 2, the magnetization rotation part generates voltage due to the magnetic flux change with the polarity shown in FIG. This causes the generated voltage to be added in the direction of addition of the U-turn bending of the wire according to the present invention, thereby doubling the generated voltage. In addition, since the U-wire bends in close proximity to the magnetic wire 1 of the outward path and the magnetic wire 1 'of the return path, the area of the loop coil formed by both wires becomes small. Therefore, the voltage due to electromagnetic coupling other than the detected voltage due to magnetization rotation can be reduced.

FIG. 7 is a view showing another embodiment, in which the magnetic body 14 is a magnetic thin wire and a magnetic body pattern, and is fixed by adhesion or vapor deposition on the surface and back of the substrate 14. Through holes 15 for connecting the pattern on the surface and the pattern on the back surface are formed in the substrate 13. In particular, in the case of producing the magnetic fine pattern, it is also possible to deposit the front magnetic film on the surface and the back surface of the substrate 13 and leave the magnetic body 14 of the three patterns by etching. In the case of disposing X and Y bidirectionally, the substrate can be formed in multiple layers.

FIG. 8 shows another embodiment in which the magnetic material 14 is repeatedly U-turned to increase the sensitivity by adding the detection voltage generated in the magnetic line to obtain a high detection voltage as a whole. A proximity sensor that detects the vertical distance with the indicator 2 with high sensitivity can be realized. Of course, as the proximity sensor, as shown in FIG. 8, a plurality of U-turn bending shapes can be used, but one wire can be used.

As the magnetic wire or the magnetic body described above, a material having a negative magnetostriction coefficient, for example, an amorphous material is effective.

Next, the coordinate input device will be described in detail according to the block diagram shown in FIG. In this figure, reference numeral 18 denotes a matrix of magnetic wires having a U-turn bending shape arranged at equal intervals in the X and Y directions, respectively. One end of all of the magnetic wires is connected to a DC bias circuit 4 which supplies a constant current through the line 19, and the other end thereof is each switching transistor of the X decoder 20 or the Y decoder 21, respectively. Is connected to the collector. The emitter of each switching transistor is connected to the same circuit part, respectively.

The wire selection circuit 23 supplies a switching signal for sequentially switching on one by one to the bases of the switching transistors of the X and Y decoders 20 and 21, and turns on the wires one by one. The bias current is supplied in turn one by one.

The coordinate detection control circuit 9 supplies a timing pulse for wire selection to the wire selection circuit 23 and supplies an alternating current for generating an alternating magnetic field to the coordinate indicator 2.

When the coordinate indicator 2 approaches the matrix 18, when the magnetic wire in the vicinity receives the bias current through the decoder, a pulse voltage as shown in Fig. 3b is generated on the line 19. . This pulse voltage is detected by the detection circuit 26 through the resistor / capacitor coupling circuit 25, sampled by the sample hold circuit 27, and then becomes a digital signal by the A / D converter 28, and the CPU The signal is processed at 29 and transmitted to the host computer (not shown) as coordinate data.

As shown in FIG. 10, the wire matrix is a magnetic wire for detecting X-direction coordinates on the panel 30 for fixing the magnetic wires in order to stabilize the vertical distance between the coordinate indicator 2 and the magnetic wires. ), (X ') and magnetic wires (1Y) and (1Y') for detecting Y-direction coordinates are arranged at regular intervals. The wires 1X, 1X ', 1Y, and 1Y' are bent U turns as shown in FIGS. 5 and 6, respectively, and the magnetization rotates through the insulator 31 between the wires. The generated voltage at the time is not short-circuited. Moreover, the insulator 31 is interposed also between the wires of a X direction and a Y direction.

In this coordinate input device, a plurality of magnetic wires are provided in the X and Y directions to generate a plurality of magnetic wires that generate a detection output corresponding to a sin indicator and a distance therefrom, and a plurality of magnets in which the detection output is increased by an alternating magnetic field generated from the coordinate indicator. Estimation of the coordinates is performed using a plurality of outputs of the wire. Thereby, even if it arrange | positions the coordinate detector of a X and a Y direction every 10 mm, 0.1 mm can be obtained as a resolution. This function is executed in the CPU 29 of FIG.

11 shows the Mateuchi effect voltage characteristics V _N-1 , which are detected at each wire when the sin indicator is located at a distance δ away from the center of each of the three wires N-1, N, N + ₁ . V _N and V _{N + 1} are shown. In this example, the distance between the wires is 5 mm.

As shown in FIG. 11, assuming that the coordinate period is between the wires N and N + 1 and located on the side close to N, the voltage V _N for the wire N and the voltage V _{N + 1 for the} wire _{N + 1} ; The voltage V _N-1 is detected in the wire N-1, respectively. In this case, V _N is the largest, then V _{N + 1} is large, by employing the value of two voltage of the larger one, when dividing the voltage V _N-1, the smaller the voltage V _N of the larger, V _{N + 1} / V _N is obtained. This value V _{N + 1} / V _N has the characteristics as shown in FIG. 12 for the distance δ from the wire center. That is, it becomes the smallest value in the wire N (δ = 0), and increases as the coordinate indicator moves from there to the right, and becomes 1 when the intermediate point (δ = 2.5) between the wire N and N + 1 is reached. . This characteristic shown in FIG. 12 has the same shape in the lateral direction from each wire. Therefore, this characteristic is stored in a memory in the CPU 29 in advance, and the wire N showing the largest detection value among the detected voltages from each wire; From the ratio (V _{N + 1} / V _N ) of the detected voltage from the wire N + 1 showing the next largest value adjacent to it, the position δ of the coordinate period from the wire N showing the largest detected voltage can be calculated. From this, the coordinate point indicated by the coordinate indicator can be calculated.

This calculation procedure is explained according to the flowchart of FIG. In this figure, first, a detection signal from a certain wire is input at step 40, and it is determined at step 41 whether the input signal is larger than a predetermined value. If it is determined NO, the process proceeds to step 43. If YES is determined in step 41, the coordinate value of the wire and the magnitude of the detected signal are recorded in the memory in step 42, and the process proceeds to step 43. In step 43, it is determined whether or not the detection of the entire wire has been completed. If NO is determined here, the flow returns to step 40 and the detection signal of the next wire is input, but if it is determined YES, the flow proceeds to step 44, where it continues Detection signals V _N-1 , V _N , V _N-1 ,... Next, in step 45, the largest of them, for example, V _N , is determined.

Next, compare the detection signals V _N-1 and ₊₁ V of the N + 1 and N-1 of the wire at both sides of the maximum output in the step 46 the wire N. If the comparison result is V _{N-1 >} V _{N + 1} , proceed to step 47 to calculate V _N-1 / V _N and refer to the table shown in FIG. 12 (stored in memory) in step 48. To obtain the value of δ. In step 49, δ is subtracted from the coordinate value of the wire N to calculate the coordinate point where the coordinate indicator is located.

The table in the step 51 according to V _N-1> V and _N-1 when it is determined that the procedure advances to Step 50, V _{N + 1} / V calculate _N, and the calculated value V _{N + 1} / V _N at step 46 By referring to the value of δ, the position coordinates of the coordinate indicator are obtained by adding δ to the coordinate value of the wire N in step 52. In this way, the coordinate calculation is completed in step 53.

Although the above-described coordinate calculation has been described with respect to one coordinate axis, the same flowchart is executed with respect to the other coordinate axis.

Next, another embodiment will be described. When a magnetization in the circumferential direction is generated on a magnetic wire of zero to negative magnetostriction coefficient, and an excitation magnetic field is applied to the excitation coil by the excitation coil, a pulse voltage at the circumferential magnetization inversion is generated according to the strength of the excitation magnetic field. At this time, if there is an external magnetic field in addition to the excitation magnetic field, the pulse voltage at the magnetization inversion is affected by both the excitation magnetic field and the external magnetic field. Therefore, if the excitation magnetic field is set to a predetermined value, the intensity of the external magnetic field can be detected. Further, by arranging a plurality of excitation coils along magnetic wires and sequentially switching excitation coils with a switch, it is possible to detect an external magnetic field in the vicinity of the corresponding excitation coil, thereby realizing a magnetic image parser.

As a method of imparting circumferential magnetization to magnetic wires having a zero to negative magnetostriction coefficient, it can be realized by applying an appropriate twist to a magnetic wire to impart a twist stress.

The circumferential magnetization was imparted by twisting a magnetic wire having a magnetostriction coefficient of zero to minus, which caused the reversal of magnetization when the external magnetic field exceeded a certain value. Generates a voltage proportional to -d? / Dt. Therefore, when an alternating magnetic field is applied to the magnetic wires, pulse voltages at the time of magnetization inversion are generated at both ends of the magnetic wires. Here, when a magnetic field other than the magnetic field due to the excitation coil is present in the vicinity of the magnetic wire, both of the synthesized magnetic fields are applied to the magnetic wire, and the internal magnetic field is reversed by the synthesized magnetic field. That is, the external magnetic field acts as a modulated signal when the excitation magnetic field is used as a carrier, and separate detection of the external magnetic field is performed by processing a signal generated by the magnetization inversion. In order to detect the external magnetic field with high resolution, the excitation magnetic field may be narrowed, and the winding may be realized by ferrite or the like.

The configuration of the magnetic image sensor according to this embodiment is shown in FIG. The magnetic image sensor includes a magnetic wire (1) as a detection body, at least one excitation coil (55) which gives a local excitation magnetic field to the wire (1), and a switching switch (56) for switching the excitation current flowing in the winding of the excitation coil. The oscillator 57 supplies an excitation current to the switching switch 56.

The detection unit of the magnetic image sensor of FIG. 14 is shown in FIG. 15, and the magnetization in the circumferential direction occurs inside the magnetic wire 1 as shown.

The direction of the internal magnetization is reversed by the excitation magnetic field of the excitation coil 55, and at this time, a pulse voltage is generated between the terminals A and B of the magnetic wire 1. The detection signal generates a pulse corresponding to the excitation current, i.e., the predetermined phase of the excitation magnetic field. However, if an external magnetic field other than the excitation magnetic field is present, a change in direction occurs in advance in part of the magnetization inside the magnetic wire 1, and in this part, it does not contribute to generating a pulse voltage at the terminals A and B by applying the excitation magnetic field. It does not come. That is, the magnitude of the detection signal is modulated by the external magnetic field. According to this principle, a pulse voltage is generated in the magnetic wire 1. The control circuit 60 controls the switching operation of the switching switch 56, and at the same time controls the magnetic image forming circuit 61 for forming a magnetic image for detecting the magnitude of the pulse voltage generated in the wire 1. The excitation magnetic field is modulated by the external magnetic field only in the part of the magnetic wire 1 to which each excitation magnetic field of the excitation coil 55 is applied, and the other part without the excitation field does not affect the pulse signal at all. Therefore, by arranging a plurality of excitation coils 55 along the magnetic wires, it is possible to improve the resolution as the magnetic image sensor. As a method of realizing the excitation coil 55, in addition to winding the ferrite rod, it is possible to realize a pattern (swirl, etc.) on a substrate by making a copper clad laminated plate into a multilayer. By arranging a plurality of excitation coils 55, by excitating them sequentially, a portion capable of detecting an external magnetic field moves along the longitudinal direction of the wire, thereby realizing a magnetic image sensor. Since the excitation current of the excitation coil is several tens or less depending on the design, a general analog switch or the like can be used as the changeover switch 56.

FIG. 16 shows the operation signal of the magnetic image sensor shown in FIG. 14, shows C1 to C4 of the excitation coils C1 to C6, and their excitation signals are sequentially switched as shown.

At this time, the detection signal is modulated by an external magnetic field near each excitation coil, and appears as a modulated detection signal having the same amplitude as the detection signal between A-B in FIG.

In the case of using magnetic wires of zero to negative magnetostriction coefficient as the magnetic wire, it is easy to cause magnetization in the circumferential direction, especially indicated by the arrow C by the twisting means 59 in Fig. 14 at a rate of about 1 turn / 10cm of the wire. As described above, magnetization is stabilized by applying a twist. Instead of twisting the wire, a bias current may flow, or after twisting, the bias current may flow.

In this embodiment, it is possible to realize a magnetic image sensor capable of detecting a wide range with a required resolution without using a precise winding operation, precision processing of a magnetic core, or semiconductor technology. In addition, the structure is very simple compared to others, and the cost of the deer is easy to down. In addition, the operation principle is a stop reading and does not depend on the moving speed of the detection medium.

Claims (10)

Means for imparting at least one magnetic wire, magnetization in the circumferential direction thereof to the magnetic wire, means for generating a plurality of alternating magnetic fields arranged along the longitudinal direction of the magnetic wire, An alternating current power source, switching means for supplying currents from the positive alternating current power source to the plurality of alternating magnetic field generating means one by one, the magnetic wire and the alternating magnetic field generating means, and a static magnetic field to be detected; Means for detecting a matew effect voltage generated between the ends of the magnetic wire by the interaction of the magnetic wires, and the detected magnetic field image is formed from a modulated signal of the detected magnetic field of the matew effect voltage detected by the detecting means. Magnetic image sensor using the matouch effect, characterized in that it comprises a means for. The magnetic image sensor according to claim 1, wherein the magnetic wire is made of a material having a magnetostriction coefficient of zero to minus. 3. The magnetic image sensor according to claim 2, wherein the circumferential magnetization means is a means for imparting a twist to the magnetic wire. The magnetic image sensor according to claim 3, wherein the twist imparting means imparts a twist to the magnetic wire at a rate of about 1 turn / 10 cm. The magnetic image sensor according to claim 3, wherein the circumferential magnetization means is a means for supplying a DC current to the magnetic wire. The magnetic image sensor according to claim 1, wherein the circumferential magnetization means is a means for supplying a DC current to the magnetic wire. 2. The magnetic image sensor according to claim 1, wherein each of the magnetic wires has a trailing path and a return path arranged in close proximity to each other. The magnetic image sensor according to claim 1, wherein insulating means are provided so as not to make electrical contact between the return path and the return path of the magnetic wire. The magnetic image sensor according to claim 1, wherein each of the plurality of alternating magnetic field generating means includes a ferrite rod and a winding wound on the ferrite rod. 10. The magnetic image sensor of claim 9, wherein the windings are stacked on a substrate in a multi-layer form.