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Publication numberUS3691502 A
Publication typeGrant
Publication dateSep 12, 1972
Filing dateApr 21, 1969
Priority dateApr 24, 1968
Publication numberUS 3691502 A, US 3691502A, US-A-3691502, US3691502 A, US3691502A
InventorsKataoka Shoei
Original AssigneeKogyo Gijutsuin
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Semiconductor type potentiometer device
US 3691502 A
Abstract
Various improvements of a semiconductor type potentiometer device comprising one or more three electrode semiconductor elements each having two end electrodes and an intermediate electrode provided at its intermediate portion, and a magnetic field applying device for applying a magnetic field to the semiconductor element while being moved along the element; these improvements being made to extend greatly the variable range of the output voltage of the device and to obtain an output voltage corresponding to one-dimensional variation as well as two-dimensional variation of the magnetic field.
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United States Patent Kataoka [451 Sept. 12, 1972 [54] SEMICONDUCTOR TYPE 3,085,159 4/1963 McNaney ..338/15 X POTENTIOMETER DEVICE 3,335,384 8/1967 Weiss ..338/32 X 3,336,558 8/1967 Wright ..338/217 [72] Japa 3,139,600 6/1964 Rasmanis et al. ..33s/32 11 [73] Assignee: Kogyo Gliutsuin (a/k), Tokyo-to, 3,286,161 11/ 1966 Jones et a1. ..323/94 Japan 3,462,673 8/1969 Hieronymus ..323/94 {22] led. Apnl 1969 Primary Examiner-Benjamin A. Botchelt PP 8179934 Assistant Examiner-R. Kinberg Attorney-Holman, Glascock, Downing 8L Seebold [301 Foreign Application Priority Data [57] ABSTRACT April 24, 1968 Japan ..43/27059 Nov. 20, 1968 Japan ..43/s44s6 Venous lmprwemems 9? semlwnducmr type P Nov. 30, 1968 Japan ..43/87324 tiometer dev'ce compr'smg one more three elec Feb. 19,1969 Japan ..44/11s12 Semiconductor elements each having we end Feb 20' 1969 Japan "44/12127 electrodes and an intermediate electrode provided at Feb. 21, 1969 Japan ..44/12s91 its intermediate Portion, and e mesnetie field pp y device for applying a magnetic field to the semicon- 52 us. c1. ..338/32 11, 323/94 11, 324/46, dneter element while being moved along the element; 330/6, 338/217, 338/283 these improvements being made to extend greatly the 51 Int. Cl. .3016 7/16 variable range of the Output voltage of the device and 58 Field 6rsm11....338/32, 32 11, 1s, 17, 18,217, to obtain an Output voltage corresponding to 338/283; 323/94 H; 324/34, 45, 46 dimensional variation as well as two-dimensional variation of the magnetic field. [56] References Cited UNITED STATES PATENTS 27 Claims, 55 Drawing Figures 1,321,682 11/1919 Thomson ..338/283 ///l JY/ PATENTED E 3.691.502

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INVENTOR S/fpil' 4 0700 kt? DIVISIONAL VOLTAGE DISTANCE OF MAGNETIC FIELD MOVEMENT By 754. M PM ATTORNEYS SEMICONDUCTOR TYPE POTENTIOMETER DEVICE BACKGROUND OF THE INVENTION The present invention relates to improvements in potentiometer devices.

Hitherto, conventional potentiometers have constructions such as shown in FIGS. 1(A) or 1(B), which comprises a resistor 1, input terminals 2, 3 and an intermediate slider 4 sliding along said resistor, one of said input terminals and said intermediate slider 4 being used as output terminals. According to the potentiometers as described above, the intermediate slider slides along the resistor, so that the resistor is liable to be damaged, or contact between the resistor and slider becomes inferior, thus causing occurrence of unfavorable noise.

As an improved potentiometer not having the disadvantage of the above-mentioned potentiometers, a new semiconductor type potentiometer device as shown in FIG. 2 has been recently proposed, said device comprising a semiconductor element 5 having magneto-resistance effect, electrodes 6 and 7 provided at both ends of said element, a central electrode 8 inserted in said element, and a magnetic field applying device for applying a magnetic field M to said element while being moved along said element. In the device of FIG. 2, when a magnetic field M is applied perpendicularly to the right half of the element 5, resistance between the electrodes 7 and 8 is increased, but resistance between the electrodes 6 and 8 is not increased. Accordingly, when a voltage is applied to the input terminals (a), (b), the voltage between the electrodes 6 and 8 is much lower than that between the electrodes 7 and 8. However, with the movement of the magnetic field toward the left half of the element, resistance between the electrodes 6 and 8 is gradually increased and that between the electrodes 7 and 8 is gradually decreased, so that the voltage between the electrodes 6 and 8 can be continuously increased by leftward movement of the magnetic field M. However, in the conventional semiconductor element having so-ca1led magneto-resistance effect, the resistance increase is only tenfold in the case of using a magnetic field of gauss. Since the magnetic field of a of conventionally practical permanent magnet is about 3 K gauss, resistance increase is about threefold. Accordingly, variable range of the output voltage of the potentiometer device as illustrated in FIG. 2 is only about 1:3.

SUMMARY OF THE INVENTION It is therefore the primary object of the present invention to provide improved and effective potentiometer devices having no disadvantages of the conventional potentiometer devices as described above.

It is another object of the present invention to provide improved and effective two-dimension type potentiometer devices not.

The foregoing objects and other objects as well as the characteristic features of the invention will become more apparent and more readily understandable by the following description and the appended claims when read in conjunction with the accompanying drawings; in which the same or equivalent members are designated by the same numerals and characters and descriptions of the same or equivalent members are omitted in the later embodiments in some cases.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1(A) and 1(B) are schematic connection views of difi'erent primitive potentiometer;

FIG. 2 is a schematic connection view of a known semiconductor type potentiometer device;

FIG. 3 is a schematic connection view of a known device corresponding to improvement of the device shown in FIG. 2;

FIG.4(A) and 4(3) are schematic connection views of two similar modifications of the device of FIG. 3;

H685, 6 and 7 are schematic connection views of different embodiments according to the invention FIG. 8 is a schematic connection view of a modification of the embodiment of FIG. 7, to which construction of the embodiment of FIG. 5 is applied;

FIG. 9 is a schematic connection view of a modification of the embodiment of FIG. 6 to which construction of the embodiment of FIG. 5 is applied;

FIG. 10 is a schematic connection view of a modifi cation of the embodiment of FIG. 7, to which construction of FIG. 5 is applied;

FIG. 11 is a schematic connection view of a modification of the embodiment of FIG. 8;

FIG. 12 is a schematic connection view of a modification of the embodiment of FIG. 10;

FIG. 13 is a schematic connection view of an improved modification of the semiconductor element of the potentiometer device of FIG. 2;

FIG. 14 is characteristic curves showing the relation between the ratio v.,,/v,,, of variable output voltage V and input voltage V and magnetic flux density;

FIG. 15 is a schematic view showing the electric field distribution (full line) and the electric potential distribution (broken line) in the case when a magnetic field is applied perpendicularly to the semiconductor element as illustrated in FIG. 13;

FIG. 16 is a perspective view showing a modification of the embodiment of FIG. 13;

FIG. 17 is a front view showing a further modification of the embodiment of FIG. 13;

FIG. 18 is a perspective view showing a practical potentiometer device according to this invention;

FIG. 19 is a schematic view showing an improved modification of the embodiment of FIG. 3;

FIG. 20 is a schematic view showing a modification of the embodiment of FIG. 19;

FIG. 21 is a further modification of the embodiment of FIG. 19;

FIG. 22 is a schematic view showing a principal modification of the semiconductor element as illustrated in FIG. 2;

FIG. 23 is a characteristic curve showing the relation between magnetic field intensity (B) and ohmic resistance (R in the device of FIG. 22;

FIG. 24 is a schematic view showing a modification of the embodiment of FIG. 22;

FIG. 25 is a schematic view showing a magnetic field applying device adapted to the embodiment of FIG. 22;

FIGS. 26 and 27 are, respectively, schematic views showing two kinds of actual potentiometer devices in which the semiconductor element of FIG. 22 is utilized;

FIG. 28 is a schematic view showing a two-dimension type potentiometer device according to the invention;

FIG. 29 is a schematic view showing an improved structure of a part of the device of FIG. 28;

FIGS. 30, 31, and 32 are different modifications of the device of FIG. 28;

FIGS. 33(A), (B), and (C) are schematic views showing a further modified potentiometer device according to the invention;

FIG. 34 is a schematic view showing an improved two-dimension type potentiometer device according to the invention, to which the device of FIG. 33 is applied;

FIGS. 35 and 36 are schematic views showing, respectively, different arrangements of the magnetic field to be applied to the device of FIG. 34;

FIG. 37 is a schematic view showing a magnetic field applying device coupled with a pickup, said device being applicable for the embodiment of FIG. 34;

FIG. 38 is a schematic view showing a modified device of the embodiment of FIG. 33, said device being of circular type;

FIGS. 39(A), (B), and (C) are schematic views showing different states of a modified device of the embodiment of FIG. 33;

FIG. 40 is a schematic view showing a semiconductor element having two end electrodes and metal layers inserted therein, said element showing principle of an improvement according to the invention;

FIGS. 41(A) and (B), FIG. 42, and FIG. 43 are schematic views showing semiconductor elements having two end electrodes, said elements comprising an improvement according to the invention;

FIG. 44 is a schematic view showing a potentiometer device to which the semiconductor element of FIG. 41 is applied; and

FIG. 45 is a characteristic curve showing the relation between the output voltage and displacement of the magnetic field applied to the element in the device of FIG. 44.

DETAILED DESCRIPTION Referring to the device of FIG. 3, the potentiometer device comprises semiconductor elements 5, 5" 5", each having two end electrodes 9 and one of the electrodes 10, l0, l0" or and one of the intermediate electrodes 11, ll, 11" or 11", respectively. The semiconductor elements are parallelly arranged and connected in common at their electrodes 9, the intermediate electrode 1 l of the first element being connected to the end electrode 10' of the second element, the intermediate electrode 11' of the second element being connected to the end electrode 10" of the third element, and so on. In the device of FIG. 3, if it is assumed that a magnetic field M produced by a magnetic field applying device (not shown) is applied to only the upper half portions of the elements, the voltage between the common electrode 9 and the intermediate electrode 11 of the first element is equal to l/a of an input voltage applied to the terminals (a) and (b) connected respectively to the electrode 10 of the first element and common electrode 9, and with all elements having the same construction, the output voltage appearing between a terminal (c) connected to the intermediate electrode 1 1" of the last stage element 5" and the terminal (b) becomes equal to (l/a)" of said input voltage. Nextly, when the position of the magnetic field M is moved to the lower portions of the elements, resistances of the elements at said lower portions are increased, whereby the output voltage between the terminals (b) and (c) is increased. In the case of the lower position of the magnetic field M, if it is assumed that the voltage between the common electrode 9 and the intermediate electrode 11 of the first element is equal to (l/b) of the input voltage applied to the input terminals (a) and (b), the output voltage between the terminals (0) and (b) becomes equal to (l/b) of the input voltage. Accordingly, the output voltage varies within the range from (l/a) to (l/b)", the ratio of which being (a/b)". In general, a b, so that in the case of the device comprising a plurality of elements arranged as described above, the rate of variation of the output voltage is remarkably larger than the case of a device comprising only one semiconductor element. For example, let it be assumed that a magnetic field of 3 K gauss is used in practice. In this case, if only one element is used, the rate of voltage variation is about 3, but if three elements having the same construction are used, said rate is 3 27.

In FIGS. 4(A) and 4(B), two different modifications of the semiconductor element assembly of FIG. 3 are shown. Referring to FIGS. 4(A) and 4(B), plural semiconductor elements 5, 5', and 5" are of arcuate shape and arranged concentrically to one another, but connections of end electrodes 10, 10' and 10", intermediate electrodes 11, 11' and 11" and a common electrode 9 are entirely the same as those in the embodiment of FIG. 3.

The semiconductor element assembly illustrated in FIG. 4(A) or 4(B) can be easily constructed by a method comprising the steps of applying a photoetching technique to a sheet of semiconductor material thereby to form concentrically separated elements and providing electrodes by evaporation-deposition of a metal while masking other portions except the portions to which the electrodes are fixed.

In the potentiometer devices as illustrated in FIGS. 3, 4(A) and 4(A), since a magnetic field is always applied to a portion of each of the semiconductor elements, the resistance between both ends of each element is always constant irrespective of position of the magnetic field. Accordingly, even when the potentiometer device is connected to any electric circuit, said device does not disturb said electric circuit at all. However, strictly speaking, since the semiconductor element of a succeeding stage is connected to intermediate electrode of the semiconductor element of the preceding stage, input resistance will be varied in accordance with variation of the position of the magnetic field. Furthermore, output voltage does not always vary in a linear relation with respect to displacement of the magnetic field. According to the invention, the above-mentioned disadvantage has been effectively avoided by the following three methods.

The first method is, as illustrated in FIG. 5, to reduce successively the width or thickness of the semiconductor element of succeeding stage than that of the semiconductor element of preceding stage, thereby to increase successively resistances of the successive elements towards the element of last stage. That is, if resistances of the successive semiconductor elements are taken respectively as R R R the elements are constructed to obtain the following relation.

According to establishment of the above relation of the resistances of the semiconductor elements, the influence afiorded to the terminals of the element of the preceding stage from the resistance of the succeeding element will become low and furthermore variation of the output voltage due to variation of the magnetic field becomes almost linear.

The second method is, as illustrated in FIG. 6, to taper or decrease width or thickness of each semiconductor element toward the common electrode 9, thereby to increase resistance of the element per unit length. In this case, with movement of position of the applied magnetic field toward lower portion, resistance of each element is increased and even when the succeeding semiconductor elements are connected in parallel, the resultant resistance between the electrodes is increased, whereby the output voltage between the terminals (b) and (c) is increased. Furthermore, linear variation of the output voltage with respect to position of the magnetic field will be established and variation of the resistance between input terminals becomes low, thus establishing an ideal potentiometer.

The third method is the same as the first and second methods in their effects, but improvement of the third method resides in that magneto-resistance characteristics of the semiconductor elements are made to become larger according as they approach to the common electrode. For this purpose, the semiconductor elements 5, 5, 5 are made of a semiconductor material, such as indium or antimonide having large transfrability, and, as illustrated in FIG. 7, many metal wires 12 are transversely deposited on the surface of each element by means of evaporation or plating method so that distance between adjacent wires is successively decreased toward the common electrode 9. According to the semiconductor element assembly constructed as above, with the movement of the magnetic field M toward the common electrode 9, resistance of the individual element increases, thereby eliminating influence due to the decrease of the resultant resistance between the electrodes, said decrease being caused by parallel connection of the elements.

The embodiment of FIG. 8 consists of the combination of the structures of the embodiments of FIGS. 5 and 7. The embodiment of FIG. 9 consists of the combination of the structures of the embodiments of FIGS. 5 and 6. The embodiment of FIG. 10 consists of the combination of the structures of the embodiments of FIGS. 8 and 9 In the case where semiconductor material such as indium or antimonide is used for the semiconductor elements, it is sometimes difficult to obtain an extremely high resistance because of low resistivity of the element.

' According to the present invention, the above-mentioned disadvantage can be effectively eliminated or reduced by constructing the semiconductor element assembly as illustrated in the embodiments of FIGS. 11 and 12, in which each of the semiconductor element is multiplexly bent in the slant direction, whereby the effective length of the element is remarkably increased, thus causing an extremely high resistance of the element. In the embodiment of FIG. 11, the width of the semiconductor element and the space between adjacent metal wires 12 are successively decreased toward succeeding stages, whereby variation of the resistance between the input terminals, caused by variation of the position of the magnetic field, is restricted.

The embodiment of FIG. 12 relates to a further improvement of the embodiment of FIG. 11 and is'equal to the latter except that the width of each semiconductor element is decreased successively toward the lower portion of the element.

The embodiments illustrated in FIGS. 5 to 12 may be modified so that their semiconductor elements are formed so as to have concentric arcuate shapes as in the case of the embodiment of FIG. 4.

Furthermore, the embodiments illustrated in FIGS. 5 to 12 can be applied to all kinds of semiconductor elements resistances of which can be varied in response to the position of a magnetic field applied thereto. Particularly, when any one of the above-mentioned embodiments is applied to a magneto-resistance element consisting of a semiconductor body such as indium, antimonide and arcynide having a large transferability, the potentiometer device manufactured by the present invention can be effectively used for any voltage having a frequency range from dc. to millimeter wavelength region, and furthermore said potentiometer device is very low in its noise and very high in its S/N in comparison with the conventional variable resistors such as volume-control devices or potentiometers. Of course, the technique according to the invention can be applied to the case of an element in which the velocity of recombination of electrons with positive holes is made to be different, depending upon any magnetic field. According to the invention, it will be easily possible toobtain a potentiometer device having no-contact, nonoise, reliability, a very high ability and long life-duration, so that said device is more effectively applicable for television, radio and the like than the conventional devices or metering apparatuses.

In the principal semiconductor element as illustrated in FIG. 2, the intermediate electrode is provided at the central point of said element. In this element, the relationship between the magnetic field and ratio of V /V is represented by the broken line characteristic curve in FIG. 14, so that voltage ratio V /V is within the range of x, x, in the practically usable range, from +B to -B,,, of the magnetic field and accordingly the variable range of the adjustable voltage is relatively narrow. This disadvantage, however, can be simply reduced by providing the intermediate electrode at a position deviated from the central point of the element, as illustrated in FIG. 13. According to the structure of the semiconductor element of FIG. 13, the above-mentioned ratio V /V is represented by the full line characteristic curve in FIG. 14. In this case, it is easily possible to increase x lx FIG. 15 shows the electric field distribution (full line) and the electric potential distribution (broken line) in the case where a magnetic field is applied perpendicularly to a semiconductor element having a rectangular form and uniform thickness and provided with two end electrodes. In the illustration of FIG. 15, when in the state of reverse direction of the magnetic field, the potential distribution (reverse to the abovementioned case with respect to right and left) and voltage ratio x lx of maximum and minimum divided voltage obtained with respect to ratio I'll of the distances 1 and 1 between the electrodes are calculated, the results of the following table are obtained.

TABLE Divisional Divisional Voltage Position ratio x, ratio x, divisional of divided with respect with respect range voltage) I to B, to B, Ja /x 0.5 0.70 0.28 2.5 0.4 0.62 0.20 3.1 0.3 0.52 0.13 4.2 0.2 0.40 0.08 5 0.1 0.28 0.04 7

As will be clear from the above table, if the position of the intermediate electrode is deviated from the central point of the semiconductor element, the adjustable range of the divided output voltage is increased. Of course, even when the intermediate electrode is provided at a central position of the semiconductor element, if the thickness or width of the element is varied along the element as shown, respectively, in FIG. 16 or FIG. 17, the same effect as that of the structure of FIG. 13 can be obtained. At any rate, it is only necessary that position of the intermediate electrode is electrically asymmetric with respect to the whole part of the semiconductor element.

An actual potentiometer device utilizing the elements as illustrated in FIGS. l3, l6 and 17 to divide a voltage is illustrated in FIG. 18, in which a semiconductor element 13 is adhered onto a magnetic disc 14 at its eccentric position and a permanent magnetic disc 15 having N and S poles along its diametrical position is superimposed on said disc 14 at a small gap therebetween. In the device of FIG. 18, if the disc 15 is rotated by rotating a knob-shaft 16 attached to said disc, the magnetic field applied to the semiconductor element 13 being continuously varied from +8., to -B,,, so that any divided output voltage within the range from x to x can be obtained. At any rate, the voltage divisional ratio obtained by moving a magnetic field applied to a semiconductor element having two end electrodes and an intermediate electrode can be made large by providing the intermediate electrode at a position where it is electrically asymmetric with respect to the whole part of said element.

The embodiment of FIG. 19 relates to a semiconductor element assembly to which the semiconductor element of FIG. 13 is applied; FIG. 20 illustrates an improvement of the embodiment of FIG. 19, in which the more the element becomes later stage, the more the element is made to be smaller, whereby electrical connection of the element is made smart; and FIG. 21 illustrates an embodiment obtained by arranging the elements in radial direction. Furthermore, according to the present invention, the potentiometer device utilizing a semiconductor element having three electrodes can be improved by adopting, as shown in FIG. 22, a circuit element consisting of a semiconductor element 5 such as illustrated in FIG. 2 and a magneto-resistance element 5a connected in series to said element 5. According to the circuit element of FIG. 22, multiplicity x /x (refer to FIG. 14) of the voltage divisional ratio can be much increased, whereby a practically effective potentiometer device can be obtained.

Referring to FIG. 22, if it be assumed that the resistance of the magneto-resistance element 50 is R this resistance is increased with an increase of the magnetic field applied to said element irrespective of the direction of the magnetic field, as shown in FIG. 23. Now, if it is assumed that the magnetic field applied to the elements 5 and 5a is varied as indicated in the following table; that is,

Magnetic-resistance element 5a 0 Semiconductor element 5 having three electrodes it is assumed that when (+B is applied to the element 5, the magnetic field is not applied to the element 5a at all, but when (-B is applied to the element 5, the magnetic field is applied also to the element 5a, and resistances of the element 5 and 5a are respectively R and R Then, the voltage divisional ratio x' (=V /V will become as follows.

where x is a voltage divisional ratio obtained by only the element 5. Furthermore, the voltage divisional ratio x in the case of application of +B, can be represented by the following equation where x is voltage divisional ratio obtained by only the element 5 and R is resistance of the element 5a. On the other hand, when a magnetic field of B,, is applied to the element, the resistance of the element 5a increases to R B9 and the voltage divisional ratio x, becomes as follows.

In this case, the multiplicity x 'lx of the dividend voltage is represented by the following equation, because RM RM Accordingly, x /x becomes larger than the case utilizing only one semiconductor element having three electrodes.

In the illustration of FIG. 22, the circuit element consists of two separated semiconductor elements which are connected in series, but said circuit element may be unified as one body as illustrated in FIG. 24, in which metal strips 17 are attached to the surface of the element so as to be perpendicular to the current direction, thereby to increase the resistance increment due to any magnetic field applied to the element.

In the circuit elements as illustrated in FIGS. 22 and 24, for the purpose of effectuating the function of the element, it is necessary that the magnetic field b applied to the magnetic-resistance element 5a only when the magnetic field is directed in a certain direction. This requirement can be satisfied by constructing the magnetic field applying permanent magnet 18 as illustrated in FIG. 25, whereby it is possible to apply the magnetic field to only the semiconductor element 5 provided with three electrodes in the case where the magnetic field is moved toward an arrow direction. Furthermore, in the case of a rotary type potentiometer device, the same object can be attained by providing eccentrically the permanent magnet 18 as illustrated in FIGS. 26 and 27. At any rate, as illustrated in FIGS. 22 and 24, a fixed potentiometer device having very improved multiplicity of the voltage divisional ratio can be easily obtained by adopting the circuit element consisting of a semiconductor element provided with three electrodes and a magneto-resistance element which is suitably combined with the former element.

In the above-mentioned potentiometer devices, only a voltage corresponding to a one dimensional physical variation (distance variation in the linear type and angle variation in the rotary type) can be obtained and any voltage corresponding to a two-dimensional physical variation cannot be obtained.

However, according to further improvement of the invention, a potentiometer device effectively responsive to two-dimensional physical variation can be obtained by modifying the above-mentioned semiconductor elements as in the embodiment of FIG. 28. The element in FIG. 28 consists of a rectangularly bent, hook-shaped semiconductor body having magneto-resistance effect. This semiconductor body can be easily manufactured by punching out a semiconductor piece according to photo-etching technique or spraying technique. The element S is provided with metal electrodes 19 at both ends, corner and intermediate portions between said corner and each of the ends, which are attached to said element according to vacuum evaporation, plating or soldering, said electrodes being provided, respectively, with terminals a a,,, e, b, and b,,. There is provided a magnetic field applying device (not shown) for applying a magnetic field Ma having the same shape as that of the element and being set at a position rotated by 180 leftward from the position of the angle-shaped element S to said element In this case, any kind of the device may be used for the magnetic field applying device, and since the direction of the magnetic field does not cause any affect to the magneto-resistance effect, a magnetic field is applied perpendicularly to the element. In the device of FIG. 28, constant voltages Va ,,e and Va,,e are respectively applied between the terminals a, and e, and a, and e.

In the device of FIG. 28, when the magnetic field Ma takes the uppermost and rightmost position, the magnetic field is applied to the transversal element at its right half portion and to the vertical element at its upper half portion. In this state, the voltage Vb e appearing between the terminals b, and e and the voltage Vb,,e appearing between the terminals b and e become minimum, respectively. With the leftward movement of the magnetic field Ma along the axis x, the voltage Vb,e is increased and with the downward movement of the magnetic field M the voltage Vb,,e is increased, but their increments are independent to each other. When the magnetic field Ma is moved toward only the axis x, the voltage Vb,,e is not varied, because the magnetic field M applied to the vertical element is not varied; and similarly when the magnetic field M is moved toward only the axis y, the voltage Va e is not varied, because the magnetic field M, applied to the transversal element is not varied. Accordingly, movement of the magnetic field M along (x y) plane causes independent voltage variations in the directions at and y. The function of the vertical element or transversal element of the element assembly of FIG. 28 can be effectively improved by inserting metal layers in the element in parallel to the surface of the electrodes thereof as shown in FIG. 29. Furthermore, if the concept of the embodiment of FIG. 3 is applied to the embodiment of FIG. 28 as illustrated in FIG. 30, variation of the divided voltage in each of the x and y directions can be additionally increased and its sensitivity is improved. The embodiment of FIG. 28 may be further modified as shown in FIG. 31. The semiconductor element assembly as illustrated in FIGS. 28, 30, or 31 can be easily manufactured from a sheet of a semiconductor plate by means of etching techniques or by forming separately respective semiconductor pieces and by electrically connecting said pieces at their comer electrodes. Furthermore, since the region of the magnetic field enclosed by dotted line in FIG. 28 is not always necessary, the magnetic field applying device maybe constructed so as to produce the magnetic field consisting of two rectangular fields which are mechanically connected so as to be perpendicular to each other. With above-mentioned devices, even when temperature of the device is varied, resistance of the semiconductor element is uniformly varied over all parts of the element, and the functional quality of the device is not affected by the temperature change. The device of FIG. 28 can be utilized to adjust the position of a needle on a x-y recorder or the position of a bright point on a Braun tube or can be utilized as a pick-up of a stereo recording device 21, as shown in FIG. 32, by attaching a recording needle 20 to a magnetic field applying device such as shown in FIG. 28 in a manner that their angle becomes 45". In the case of the application of the device to a pick-up, since only the part of the displacement is required to be converted to an electric signal, absolute position is voluntary and it is only necessary that the magnetic field is over the intermediate electrodes of the semiconductor elements.

The two-dimensional potentiometer device as illustrated in FIG. 28 can be further improved according to the invention so that an absolute value of an electric signal (positive voltage in the case of displacement of positive direction and negative voltage in the case of displacement of reverse direction) corresponding to an absolute value of any displacement of a magnetic field can be obtained. According to this improvement, there is scarcely an affect due to temperature in spite of using a semiconductor element and a displacement along a two-dimensional plane can be converted to two kinds of independent electrical signals. This improved embodiment of the invention is illustrated in FIG. 33, in which the device comprises a semiconductor element 5 having a magneto-resistance characteristic and is provided with two end electrodes 22, 23, a central electrode 24 and additionally intermediate electrodes 25, 26 which are respectively provided between the electrodes 22 and 24 and between the electrode 24 and 23; two magnets M M which are coupled mechanically so that they are simultaneously moved rightward and leftward; and a dc. voltage source BS one terminal of which is connected to the central electrode 24 and the other terminal of which is connected to two end electrodes 22 and 23. In the case where the magnets M, are positioned respectively at middle portions of the addi tional electrodes 25 and 26 as shown in FIG. 33(A), areas of the element portions being not applied with the magnetic field are the same in the regions between the electrodes 22 and 25, 25 and 24, 24 and 26, and 26 and 23, and similarly areas of the element portions being I I applied with the magnetic field are same. Accordingly, potentials of the electrodes 25 and 26 are the same and equal to V/2, where V the represents voltage of the voltage source BS, so that any output voltage does not appear between the terminals (a) and (b) connected respectively to the electrodes 25 and 26. On the other hand, when the magnets M, are moved rightward as shown in FIG. 33(B), areas of the element portions being applied respectively with the magnetic field between the electrodes 22 and 25 and that between the electrodes 24 and 26 are decreased and the resistance of said portions are decreased; and furthermore areas of the element portions being applied respectively with the magnetic field between the electrodes 25 and 24 I and that between the electrodes 26 and 23 are increased and resistances of said portions are increased, and accordingly, the potential of the electrode 25 is increased by A V and becomes (V /2) AV and the potential of the electrode 26 is decreased by AV and becomes (V/2) AV, thus producing an output voltage of 2 AV between the terminals (a) and (b). n the contrary, as shown in FIG. 33(C), when the two magnetic fields are moved by A2: leftward with respect to the semiconductor element, the resistances at various portions of the element become reverse to the case of FIG. 33(B) and an output voltage of (-2 AV) will be produced between the terminals (a) and (b). That is, an output voltage corresponding to the absolute value of the displacement Ax of the magnetic field can be obtained. Accordingly, the device as illustrated in FIG. 33 can be applied to not only an absolute-displacement meter, but also to detection of any relafive displacement or vibration or conversion of any electric signal and furthermore to any seismometer or vibration picking-up.

According to a further improvement of the inven tion, it is possible to obtain a device adapted to a detect two-dimensional displacement by assembling suitably the devices as illustrated in FIG. 33. The embodiment of FIG. 34 relates to a two-dimensional device obtained by perpendicularly combining two identical devices which are completely equal to that of FIG. 33, but small character x is put to various members in the xdirection and small character y is put to the members in the y-direction. However, tee magnetic field to, be applied to the semiconductor elements is made to be different from that of the embodiment of FIG. 33. That is, in FIG. 34, the magnetic field M is of square shape having a central square space and takes a symmetrical position over the combined central electrode 24 in the case of zero displacement thereof, widths of the four sides of the magnetic field M,, being, respectively, symmetric with respect to the additional central electrodes 25,, 25,, 26,, and 26,, so that in each arm of the semiconductor element assembly the, area being applied with the magnetic field and the area being not applied with the magnetic field are equal to each other. If the magnetic field M is moved in transversal (x) direction with respect to the semiconductor element assembly from the symmetric position shown in FIG. 34, an output voltage in proportion to the component of the displacement of the magnetic field is produced between the terminals a and b, as in the case of the device in FIG. 33. This voltage produced between the terminals a, and b, is not affected by the vertical (yaxis) displacement of the magnetic field M because in the transversal direction, positions of the portions of two transversal arms of the semiconductor element assembly, said portions being applied with the magnetic field, are not changed by the displacement of the magnetic field in the vertical (y-axis) direction. Similarly, between the terminals a and b,,, only the output voltage corresponding to y component of the displacement of the magnetic field M is produced. As is clear from the above-mentioned description, any two-dimensional displacement of the magnetic field Mc can be converted to two independent output voltages. In the embodiment of FIG. 34, a square frame-shaped magnetic field is adopted, but four corner portions of said field are not necessary in practice, so that four magnets each producing a rectangular magnetic field may be mechanically coupled so as to be commonly moved. From a viewpoint of magneto-resistance effect, since only the magnetic field component applied perpendicularly to the semiconductor element is effective in practice, any magnetic field having any direction may be adopted. In practice, a permanent magnet may be formed to apply the necessary magnetic field or a mag net provided with a magnetic body having a shape adapted to distribute the necessary magnetic field may be adopted.

In FIGS. 35 and 36, illustrations of magnetization of the magnetic body are shown, said FIGS. corresponding, respectively, to one-dimensional case and twodimensional case. In both cases illustrated in FIGS. 33 and 34, resistances of all arms of the element viewed from the center point of the element are not always required to be equal to one another, and it is not necessary to position the central electrode at strictly the center point of the element. In this later case, said slightly deviated point is taken as the zero displacement of the magnetic field, because at said point the output voltage between the terminals (a) and (b) becomes zero. Furthermore, in the case where it is only required to convert the change of a relative displacement with respect to time to an electric signal as in the case of a vibration pick-up, zero-position of a displacement is not indespensably necessary provided that the magnetic field M is over the central electrode.

The converter for converting two-dimensional displacement to electric signals can be applied to a stereopick-up. This example is shown in FIG. 37, in which a needle 20 affixed to a magnetic body 22 converts a two-dimensional vibration recorded in a slot of a recording plate 21, thus causing the possibility of regeneration of stereo.

In the various potentiometer devices according to the invention, an ac. power source having a frequency may be used in the place of a dc. voltage source. In this case, a signal having said frequency is modulated in accordance with the absolute value of the displacement of the magnetic field, so that application of the device to a communication technique or an information processing technique can be made possible.

The embodiment of FIG. 33 can be modified so as to have an arcuate or circular form, thereby to convert any angular displacement of the magnetic field to an electric quantity. FIG. 38 relates to an illustration, in which an arcuate semiconductor element 5 provided with two end electrodes 22 and 23 and a central elec- 13 trode 24 and two additional intermediate electrodes 25 and 26 having, respectively, terminals (a) and (b) is used. The electrodes 22 and 23 are connected in com mon and a voltage source BS is connected between said common electrode (22, 23) and the central electrode 24.

In the embodiment of FIG. 38, if both magnetic fields M, which are concentrically and symmetrically disposed with respect to the semiconductor element 5 are made to rotate by an angle A0, an output voltage corresponding to the angle A will be produced between the terminals (3.) and (b), as is similar to the case of the embodiment of FIG. 33. Of course, the embodiment of FIG. 38 can be modified so that the element has a closed circular form and the electrodes 22 and 23 are unified. In this case also, the same operation and effect as those in the case of FIG. 38 can be obtained.

In the embodiments from FIG. 33 to FIG. 38, two magnetic fields are parallelly moved, but said magnetic fields may be replaced by a magnetic field M which is applied symmetrically with respect to the central electrode 24, as shown in FIG. 39. In the case where the magnetic field M is applied symmetrically to the semiconductor element 5, as shown in FIG. 39(A), the potentials of the electrodes 25 and 26 are equal to kV (V and k represent voltage of the source BS and constant, respectively), and accordingly an output voltage would not be produced between the terminals (a) and (b). However, if the magnetic field M is moved rightward as shown in FIG. 39(B), the resistance between the electrodes 26 and 24 is increased, whereby the potential of the electrode 26 increases to (kV A V). On the other hand, since the resistance between the electrodes 25 and 24 is decreased, the potential of the electrode 25 decreases to (kV A V). As a result, a voltage of 2 AV will be produced between the terminals (a) and (b). Similarly, if the magnetic field M is moved leftward, a voltage of 2 AV) will be produced between the terminals (a) and (b).

The. principle of the embodiment of FIG. 39 can be applied to the embodiments of FIG. 34 and 38, with the same effect as that in the embodiment of FIG. 39.

The current passing through the semiconductor elements illustrated in the above-mentioned embodiments flows in parallel to the electric field in the case of applying no magnetic field to the element, but if a magnetic field is applied to such a semiconductor element 5 having two end electrodes 6, 7 as shown in FIG. 40, current i (broken line) flows toward a direction having an angle 0 with respect to the electric field (full line'). This is known as a so-called Hall Efiect. The angle 0 depends upon direction of the magnetic field applied and the type of the semiconductor element (N-type or P- type). Furthermore, the angle 0 is denoted as a Hall angle and the more transferability of the carrier of the semiconductor body is larger or the intensity of the magnetic field is larger, the more said angle becomes larger.

On the other hand in the case of FIG. 40, resistivity of the semiconductor body is increased by application of a magnetic field thereto, but said increase is very low. Accordingly, for the purpose of obtaining a practical magneto-resistance element, it is preferable, as shown in FIG. 40, to insert a plurality of metal layers l2 in the semiconductive element so as to be perpendicular to the longitudinal direction of the element. The metal layers 12 may be provided by any method such as soldering, vacuum evaporation and plating. Due to existence of the metal layers, the electric field E must be perpendicular to the metal layers, so that direction of the current is inclined by application of a magnetic field to the element, whereby current passage is lengthened, thus increasing resistance of the element. However, even when the metal layers 12 are provided, resistance increment caused by a magnetic field is not large unless the distance between adjacent metal layers 12 is extremely shortened. Furthermore, the abovementioned effect due to the metal layers 12 is particularly great at the region near the metal layer, so that resistance variation becomes stepwise. These disadvantages can be effectively reduced, according to the invention, by providing the metal layers 12 so as to be inclined with respect to the direction of the semiconductor element 5, as shown in FIG. 41. FIG. 41(A) shows the case in which a magnetic field H directed frontward from a rear side of the view surface is applied to a semiconductor element of N type, in which the electric field E is perpendicular to the metal layer 12 at point p, so that the current i flows transversely so as to have the Hall angle 0. However, at point q, the current strikes against the side surface of the element and cannot flow further.

According to the embodiment of FIG. 41(A), length of the current passage is increased more than the case when a magnetic field is not applied to the element, whereby resistance between two end electrodes 6 and 7 of the element 5 is increased. Of course, since the current flowing from the point q disappears in practice, distortion of the electric field will occur in the element and perpendicularity of the electric field to the metal layers is somewhat distorted, but as a whole, the efiect is substantially same. However, when the application direction of the magnetic field is reversed as shown in FIG. 41(B), the current flows rather uniformly at all parts of the element. The embodiment of FIG. 41 can be further improved by providing two end electrodes 6 and 7 so as to be parallel to the metal layers 12 as shown in FIG. 42. Furthermore, in the embodiments of FIGS. 41 and 42, the electrodes 6 and 7 and the metal layers 12 may be formed so as to have an angled-shape as shown in FIG. 43 or an arcuate shape.

A potentiometer device obtained by utilizing a three terminal semiconductor element to which the principle of metal layer inclination is applied and a magnetic field applying device for applying a magnetic field M to said element while being moved along said element is shown in FIG. 44. According to the embodiment of FIG. 44, the output voltage produced between a central electrode and an end electrode 7 in the case of applying a voltage between the electrodes 6 and 7 can be adjusted as shown in FIG. 45 by movement of the magnetic field M along the element 5.

Furthermore, the principle of inclining the metal layers to be inserted in the semiconductor element can be effectively applied to the various embodiments of FIGS. 7, 8, 10, ll, 12, 24, and 29, thereby to improve ability of the device. Of course, inclined metal layers may be inserted in the element of FIG. 4.

I claim:

1. A semiconductor potentiometer device comprising an assembly of at least two three-terminal semiconductor elements each with a different resistance, each element having first and second end electrodes and an intermediate electrode, all first end electrodes of said elements being connected to a common input terminal, the intermediate electrode of said element with the least resistance being connected to the second end electrode of said element with the second least resistance, the intermediate electrode of said element with the second least resistance being connecting to the second end electrode of any existing element with the third least resistance, the intermediate electrode of any existing element with the third least resistance being connecting to the intermediate electrode of any existing element with the fourth least resistance, and so on in cascade fashion, and wherein the intermediate electrode of said element with the largest resistance is connected to an output terminal; magnetic field applying means for applying a common magnetic field to said semiconductor element assembly; and means for changing the relative position of said magnetic field on said semiconductor assembly. v

2. A semiconductor type potentiometer device as claimed in claim 1, in which the semiconductor elements of the assembly are of arcuate shape and arranged concentrically to one another.

3. A semiconductor type potentiometer device as claimed in claim 1, in which each of the semiconductor elements of the assembly decreases in cross-section gradually toward the common electrode.

4. A semiconductor type potentiometer device as claimed in claim 1, in which each of the semiconductor elements of the assembly has a magneto-resistance characteristic which is made larger according as it approaches to the common electrode.

5. A semiconductor type potentiometer device as claimed in claim 4, in which each of the semiconductor elements is provided with many metal members provided transversely on the surface so that distance between adjacent metal members is successively decreased toward the common electrode.

6. A semiconductor type potential device as claimed in claim 1, in which each of the semiconductor elements of the assembly has a shape obtained by bending it in a zigzag state along its length.

7. A semiconductor element adapted to a semiconductor type potentiometer device comprising a threeterminal semiconductor element having first and second end electrodes and an intermediate electrode and a magnetic field applying means for applying a magnetic field to said semiconductor element while causing relative movement of said element and magnetic field; said element being provided with at least one slant metal piece inserted therein so as to be inclined at a constant angle with respect to the side edges of the element along the length thereof.

8. A semiconductor element adapted to a semiconductor type potentiometer device comprising a threeterminal semiconductor element having first and second end electrodes and an intermediate electrode and a magnetic field applying means for applying a magnetic field to said semiconductor element while causing relative movement of said element and magnetic field; said element being provided with at least one metal piece inserted therein and having an angled shape.

9. A semiconductor type potentiometer device as claimed in claim 1, in which, the intermediate electrode of each of the semiconductor elements is made to be electrically asymmetric with respect to both ends of said element.

10. In a semiconductor type potentiometer device comprising a three-terminal semiconductor element having first and second end electrodes and an intermediate electrode and a magnetic field applying means for applying a magnetic field to said semiconductor element while causing relative movement of said element and magnetic field; an improvement of said device, in which said element is provided with a magneto-resistance element connected in series thereto, the free end electrodes of said elements being input terminals and the free end electrode and intermediate electrode of said semiconductor element being output terminals, and the magnetic field applying means comprising means adapted to apply the magnetic field to said magneto-resistance element only when the magnetic field is directed to a certain direction.

11. A semiconductor type potentiometer device as claimed in claim 10, in which the three-electrode semiconductor element and the magneto-resistance element which are connected in series are unified as one body.

12. A semiconductor type potentiometer comprising an angle-shaped semiconductor element provided with electrodes at both ends, at the corner, and at intermediate portions between said comer and each of said both ends, and means for applying to said element a magnetic field having the same shape as that of said element and being set at a position rotated by from the position of said element while causing relative movement of said element and means, a pair of electrodes at one end and the comer of the element forming one side input terminal pair, another pair of electrodes at another end and the comer of the element forming another side input terminal pair, and the two intermediate electrodes forming output terminals, thereby to make the device responsive to two-dimensional physical variation.

13. A semiconductor type potentiometer as claimed in claim 12, in which the semiconductor element is provided with metal members inserted therein disposed in parallel to the surface of the electrodes.

14. A semiconductor type potentiometer as claimed in claim 12, in which each of the vertical and transversal parts of the angle-shaped semiconductor element consists of at least two cascade-connected semiconductor elements.

15. A semiconductor type potentiometer as claimed in claim 12, in which each of the vertical and transversal parts of the angle-shaped semiconductor element consists of zigzag-shaped semiconductor element.

16. A semiconductor type potentiometer, comprising a semiconductor element having a magneto-resistance characteristic and provided with two end electrodes, a central electrode and additional intermediate electrodes which are respectively provided between said end electrodes and said central electrode, and comprising two magnetic field applying means which are mechanically coupled so as to be simultaneously

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US3993946 *Dec 4, 1974Nov 23, 1976Sony CorporationApparatus for measuring the direction and relative position between a body and a pick-up using a magnetoresistive pick up
US4251795 *Nov 29, 1978Feb 17, 1981Asahi Kasei Kogyo Kabushiki KaishaSemiconductor magnetoresistive element having a differential effect
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Classifications
U.S. Classification338/32.00R, 338/217, 324/207.21, 257/425, 323/368, 330/6, 338/283
International ClassificationH01C10/00
Cooperative ClassificationH01C10/00
European ClassificationH01C10/00