WO2011136054A1 - Position detection device - Google Patents

Abstract

Disclosed is a position detection device with even higher resolution. In the position detection device (1), a first element (4_A) is connected in series between a first output terminal (8a) and a first power supply terminal (6) and comprises 2ⁿ first detection elements disposed in apposition along the x-direction, a third element (4_C) is connected in series between a second output terminal (8b) and the first power supply terminal (6) and comprises 2ⁿ first detection elements disposed in apposition along the x-direction, the arrangement of the 2ⁿ first detection elements in the x-direction is determined in a manner such that at least the linear phase term is removed from the combined signal of the respective read signals of said 2ⁿ first detection elements, and a position acquisition unit (9) calculates the position of an object that is the subject of position detection on the basis of the signal output from the first output terminal (8a) and the signal output from the second output terminal (8b).

Description

Position detection device

The present invention relates to a position detection device, and more particularly, to a detection element configured to generate a predetermined readout signal corresponding to a scale facing position when moving along a scale and a scale surface such as a magnetic scale or an optical scale. The present invention relates to a position detection device to be used.

Some industrial equipment such as mounters include a position detection device that detects the position of an object using magnetism or a light beam in order to detect the position of the moving object.

FIG. 23A is a diagram showing a configuration of a position detection apparatus 10 of a type (magnetic type) that uses magnetism. As shown in the figure, the position detection device 10 has a magnetic sensor 20 attached to a position detection target object (not shown) and a surface 30a extending in the moving direction of the object (hereinafter referred to as the x direction). The surface 30a is provided with a magnetic scale 30 magnetized so that N poles and S poles appear alternately at equal intervals.

FIG. 23A also shows the strength of the magnetic field formed by the magnetic scale 30. As shown in the figure, the strength of the magnetic field formed by the magnetic scale 30 is expressed as a sine wave having a wavelength of 2λ, where λ is the width (length in the x direction) of each magnetic pole appearing on the surface 30a of the magnetic scale 30. Approximated.

As shown in FIG. 23A, the magnetic sensor 20 has four AMR (Anisotropic magnetoresistive) elements MRA to MRD, which are arranged at an interval of λ / 4 along the x direction.

FIG. 23B is a diagram showing an electrical connection form of the AMR elements MRA to MRD. As shown in the figure, in the magnetic sensor 20, the AMR element MRA and the AMR element MRC are half-bridge connected, and the AMR element MRB and the AMR element MRD are half-bridge connected. There are two output signals from the magnetic sensor 20, one output signal Vsin is taken out from the connection point between the AMR element MRA and the AMR element MRC, and the other output signal Vcos is taken out from the connection point between the AMR element MRB and the AMR element MRD. .

An AMR element is an element whose resistance value changes depending on the strength of an applied magnetic field. FIG. 23A also shows a change in the resistance value (read signal) of the AMR element when the AMR element moves in the x direction. As shown in the figure, the resistance value of the AMR element changes at a wavelength λ that is half of the magnetic field formed by the magnetic scale 30.

FIG. 24 is a diagram showing changes in the resistance values R _MRA to R _MRD and the output signals Vsin and Vcos of the AMR elements MRA to MRD when the position detection target object moves in the x direction. As shown in the figure, the resistance values R _MRA to R _MRD are shifted in phase by π / 4. This corresponds to the fact that the AMR elements MRA to MRD are arranged at intervals of λ / 4 along the x direction. Further, the output signals Vsin and Vcos also change with the wavelength λ, and their phases differ from each other by π / 4.

The resistance values R _MRA to R _MRD of the AMR elements MRA to MRD are approximately expressed as the following equations (1) to (4), respectively. However, θ = 2π · x / λ, and A ₀ and A ₁ are constants.

From the expressions (1) to (4), the output signals Vsin and Vcos are expressed by the following expressions (5) and (6), respectively. However, in the equations (5) and (6), the 0th-order term component of θ is removed. Since the zero-order term component is known, it can be removed by subtraction processing. Note that it is not appropriate to use a filter to remove the 0th-order term component. This is because the position detection device needs to detect the position of a stationary object.

The position x of the object is obtained by the following equation (7) using the output signals Vsin and Vcos obtained as described above.

By the way, in the equations (1) to (4), it is assumed that the read signal of the AMR element is a perfect sine wave, but it is not actually a perfect sine wave. When this is expressed by using Fourier series expansion, the read signals of the resistance values R _MRA to R _MRD are expressed by the following equations (8) to (11), respectively. _{However, A 2,} A _3, ··· is a constant. As is clear from these equations, the read signals of the resistance values R _MRA to R _MRD include harmonic components.

When the output signals Vsin and Vcos are obtained in consideration of harmonic components, the following equations (12) and (13) are obtained, respectively.

As understood from the equations (12) and (13), harmonic components remain in the output signals Vsin and Vcos, which causes an error in the position x obtained by the equation (7). Therefore, it is preferable to remove harmonic components appearing in the resistance values R _MRA to R _MRD . In this regard, for example, Patent Document 1 discloses a technique for removing odd-order harmonics.

Also, as understood from the equations (12) and (13), the 0th-order component (DC component) of θ remains in the output signals Vsin and Vcos. The DC component can be removed by subtraction processing as described above, but can also be removed by using a full bridge connection. Therefore, the full bridge connection will be described below.

FIG. 25 is a diagram showing a specific connection form of the AMR elements MRA to MRD when a full bridge connection is applied to the magnetic sensor 20. As shown in the figure, when full bridge connection is performed, two sets of half bridges shown in FIG. 23B are prepared. The output from each set is input to the inverting input terminal and the non-inverting input terminal of the operational amplifier, respectively, and the output of the operational amplifier becomes the output signals Vsin and Vcos.

In the example of FIG. 25, the output signals Vsin and Vcos are expressed by the following equations (14) and (15), respectively.

As understood from the comparison between the equations (12) and (13), according to the equations (14) and (15), the term Vcc / 2 is removed from the output signals Vsin and Vcos. This indicates that the DC component is removed from the output signals Vsin and Vcos by performing the full bridge connection.

Japanese Patent No. 3118960

By the way, as a detection element, various elements other than the above-described AMR element are known. Among these, it is known that a GMR (giant magnetomagnetoresistive) element can obtain a larger output than other detection elements. If a position detection device is configured using a GMR element, it is possible to obtain a larger output than when an AMR element is used.

However, the GMR element has a problem that its resistance value changes with the wavelength of the magnetic field formed by the magnetic scale 30 (twice that of the AMR element) at least as long as it is used in a normal manner. This means that a position detection apparatus using a GMR element can only obtain a resolution of 1/2 that of an apparatus using an AMR element. Thus, it is difficult to configure a position detection device using a GMR element, no matter how high the output is. Therefore, there is a need for a position detection device with higher resolution so that a GMR element can be used as the detection element.

In the point that a position detection device having higher resolution is required, the situation is the same in the type (optical type) position detection device using a light beam. That is, in the optical position detection device, a reflecting plate (optical scale) having a diffraction pattern formed on the surface is used instead of the magnetic scale, and the optical scale is irradiated with a light beam. An optical sensor is used instead of the magnetic sensor, and the optical sensor receives the light beam reflected by the optical scale. The amount of light received at this time is the same as the readout signal shown in equations (8) to (11), and the resolution decreases as the wavelength increases. Therefore, as for the optical position detection device, a position detection device having higher resolution is required as in the case of the position detection device using magnetism.

Therefore, one of the objects of the present invention is to provide a position detection device having higher resolution.

In order to achieve the above object, a position detection device according to the present invention is configured to have a scale having a first surface extending along a moving direction of an object to be position-detected, to be movable together with the object, and to the first. And a position acquisition means for acquiring the position of the position detection target object based on an output signal of the sensor, and the sensor is supplied with a first power supply potential. A first power supply terminal, a second power supply terminal supplied with a second power supply potential different from the first power supply potential, first and second output terminals, and the first output terminal A first element connected between the first power supply terminal; a second element connected between the second power supply terminal and the first output terminal; and the second output. A third terminal connected between the terminal and the first power supply terminal And a fourth element connected between the second power supply terminal and the second output terminal, wherein the first element includes the first output terminal and the first output terminal. The third element includes a plurality of first detection elements connected in series between the power supply terminals and juxtaposed along the moving direction, and the third element includes the second output terminal and the first power supply. A plurality of third detection elements connected in series with each other along the moving direction, and each of the first detection elements and each of the third detection elements is respectively When moving along the surface of 1 in the moving direction, it is configured to generate a predetermined readout signal corresponding to the position facing the scale, and the arrangement of the plurality of first detection elements in the moving direction is: At least the first-order component of the phase is removed from the voltage signal appearing at the first output terminal. The arrangement of the plurality of third detection elements in the moving direction is determined so that at least a first-order component of a phase is removed from a voltage signal appearing at the second output terminal, and the position The acquisition means calculates the position of the position detection target object based on a voltage signal appearing at the first output terminal and a voltage signal appearing at the second output terminal.

According to the present invention, the second and higher harmonics become the fundamental wave. Therefore, it is possible to obtain a resolution that is at least twice that of the conventional position detection device. In the present invention, “movement” means relative movement of the position detection target object and the scale. That is, for example, considering the ground surface as a reference, the scale may be fixed with respect to the ground surface, and the object may move with respect to the ground surface, or the object may be fixed with respect to the ground surface, and the scale may be It is also possible that both the object and the scale move in different directions with respect to the ground surface. Note that the power supply potential may be a constant voltage source potential or a constant current source potential.

In the position detection device, the second element is connected in series between the second power supply terminal and the first output terminal, and a plurality of second elements arranged in parallel along the moving direction. The fourth element includes a plurality of fourth detection elements connected in series between the second power supply terminal and the second output terminal and juxtaposed along the moving direction. An arrangement of the plurality of second detection elements in the moving direction is determined such that at least a first-order component of a phase is removed from a voltage signal appearing at the first output terminal; The arrangement of the fourth detection elements in the moving direction may be determined so that at least a first-order component of the phase is removed from the voltage signal appearing at the second output terminal. According to this, the temperature characteristics of the first to fourth elements can be made uniform.

In the position detection device, the first element includes 2 ⁿ (n is a number selected from an arbitrary natural number) first detection elements, and the third element is 2 ^{When n} = 1, the 2 ⁿ first detection elements are each separated by ± π / 2 from the first reference position in the movement direction. When n ≧ 2 are arranged one by one at the first and second positions, respectively, 2 ⁿ separated from the first position by ± π / 8... ± π / 2 ^{n + 1 in the} moving direction. ^-1 each at 1 position and 1 at 2 ^n-1 positions away from the second position by ± π / 8 ... ± π / 2 ^{n + 1 in the} moving direction, respectively. the 2 ⁿ pieces of the third detector element, a first predetermined distance Shifts each said 2 ⁿ pieces of the first detecting element in the direction of movement It may be placed in position. According to this, the second harmonic becomes the fundamental wave. Therefore, it is possible to obtain twice the resolution as compared with the conventional position detecting device.

Furthermore, in this position detection apparatus, the second element includes 2 ⁿ second detection elements, the fourth element includes 2 ⁿ fourth detection elements, and the 2 ^{When n} = 1, the n second detection elements have a second distance of πl / 2 (where l is a number selected from an arbitrary odd number) away from the first reference position in the movement direction. When n ≧ 2, the reference positions are further separated from each other by ± π / 2 in the moving direction, and when n ≧ 2, respectively, ± π / 8 in the moving direction from the third position. ... ^{1 at} 2 ^n-1 positions separated by ± π / 2 ^{n + 1,} and ± π / 8 at the moving direction from the fourth position, respectively, 2 ^n- separated by ± π / 2 ^{n + 1. One} piece is arranged at one position, and the 2 ⁿ fourth detection elements are the 2 ⁿ second detection elements. Each may be arranged at a position shifted by a second predetermined distance in the moving direction. According to this, the temperature characteristics of the first to fourth elements can be made uniform.

In the position detection device, the first element includes 2 ⁿ (n is a number selected from an arbitrary natural number) first detection elements, and the third element is 2 ^{It is} composed of ⁿ third detection elements, and the arrangement of the 2 ⁿ first detection elements in the moving direction is other than a 2 ^k order component (k is a number selected from an arbitrary natural number) It is determined that n components selected from power-of-two components of 2 and 2 ^k P-order components (P is a prime number of 3 or more) are removed, and the 2 ⁿ third detection elements are The 2 ⁿ first detection elements may be arranged at positions shifted by a first predetermined distance in the moving direction. According to this, higher harmonics than the fundamental wave can be appropriately removed.

Furthermore, in this position detection apparatus, the second element includes 2 ⁿ second detection elements, the fourth element includes 2 ⁿ fourth detection elements, and the 2 ^{The n} second detection elements are arranged at positions where the 2 ⁿ first detection elements are shifted by a third predetermined distance in the movement direction, and the 2 ⁿ fourth detection elements are: Each of the 2 ⁿ second detection elements may be arranged at a position shifted by a second predetermined distance in the movement direction. According to this, the temperature characteristics of the first to fourth elements can be made uniform.

In the position detection apparatus, the first element includes 2 ⁿ (n is a number selected from any two or more natural numbers) first detection elements, and the third element Is composed of 2 ⁿ third detection elements, and the 2 ⁿ first detection elements are separated by + π / 2 from the first reference position in the moving direction when n = 2. The second position is further separated from the first reference position by −π / 2 in the moving direction, one at each of the fifth and sixth positions that are further separated by ± π / 4 in the moving direction from the first position. One in each of the seventh and eighth positions further away from the position in the moving direction by ± π / 4, respectively, and when n ≧ 3, the fifth position in the moving direction, respectively. ± π / 16... ± π / 2 ^{n + 1 one} by 2 ^n-2 positions apart from the sixth position The one on the moving direction, each ± π / 16 ··· ± π / 2 n + 1 apart 2 ^n-2 pieces of position, the seventh, respectively ± π / 16 ··· ± in the moving direction from the position of π ^{/ 2 n + 1} one by one to the distant ^{2 n-2} pieces of position, the eighth, respectively ^{± π / 16 ··· ± π /} 2 n + 1 apart ^{2 n-2} pieces of position in the moving direction from the position of The 2 ⁿ third detection elements are arranged at positions shifted from the 2 ⁿ first detection elements by a first predetermined distance in the moving direction. It is good. According to this, the fourth harmonic becomes the fundamental wave. Accordingly, it is possible to obtain a resolution four times that of the conventional position detection device.

Furthermore, in this position detection apparatus, the second element includes 2 ⁿ second detection elements, the fourth element includes 2 ⁿ fourth detection elements, and the 2 ^In the case where n = 2, the n second detection elements are separated by πl / 4 (l is a number selected from an arbitrary odd number) in the movement direction from the first reference position. One from each of the second reference position and each of the ninth and tenth positions further ± π / 4 in the movement direction from the third position further + π / 2 in the movement direction from the reference position. In the case where n ≧ 3, one is arranged at each of the eleventh and twelfth positions separated by ± π / 4 in the moving direction from the fourth position separated by −π / 2 in the moving direction, respectively. , respectively in the moving direction from the position of the first 9 ± π / 16 ··· ± π / 2 n + 1 away One for ^{2 n-2} pieces of positions, one for the first 10 respectively ^{± π / 16 ··· ± π /} 2 n + 1 apart ^{2 n-2} pieces of position in the moving direction from the position of, One at each of 2 ⁿ⁻² positions ± π / 16... ± π / 2 ^{n + 1} apart from the eleventh position in the moving direction and ± π from the twelfth position in the moving direction, respectively. / 16... ± π / 2 ^{n + 1} one by one at 2 ⁿ⁻² positions, and the 2 ⁿ fourth detection elements are the 2 ⁿ second detection elements. Each may be arranged at a position shifted by a second predetermined distance in the moving direction. According to this, the temperature characteristics of the first to fourth elements can be made uniform.

In each of the position detection devices, the scale is a magnetic scale magnetized so that N poles and S poles alternately appear along the moving direction on the first surface, and the detection element is magnetic. It may be a resistance element. According to this, in the position detection device using magnetism, it becomes possible to obtain a resolution more than twice that of the conventional one. Therefore, even if a GMR element that can obtain only half the resolution of the AMR element is used, a resolution equivalent to or higher than that of the conventional one can be obtained, so that the GMR element can be used as the detection element.

In each of the position detection devices, the scale is a magnetic scale magnetized so that N poles and S poles alternately appear along the moving direction on the first surface, and the detection element is magnetic. Each of the second and fourth elements may be a resistance element configured so as not to be affected by a magnetic field formed by the magnetic scale.

Further, in each of the position detection devices described above, the magnetoresistive element may be any one of a GMR element, an AMR element, and a TMR element.

In each of the position detection devices, the scale may be an optical scale having a diffraction pattern formed on the first surface, and the detection element may be a light detection element. According to this, in the optical position detection device, it becomes possible to obtain a resolution that is at least twice that of the conventional one.

In the position detection device, each of the second and fourth elements may be a constant current source.

In each of the position detection devices, the first power supply potential may be a ground potential.

According to another aspect of the present invention, there is provided a position detection apparatus configured to be movable with a scale having a first surface extending along a moving direction of an object to be detected, and the first object. And a position acquisition means for acquiring the position of the position detection target object based on an output signal of the sensor, and the sensor is supplied with a first power supply potential. A first power supply terminal, a second power supply terminal supplied with a second power supply potential different from the first power supply potential, first and second output terminals, and the first output terminal A first element connected between the first power supply terminal; a second element connected between the second power supply terminal and the first output terminal; and the second output. A third element connected between the terminal and the first power supply terminal; A fourth element connected between the second power supply terminal and the second output terminal, wherein the first element includes the first output terminal, the first power supply terminal, And a plurality of first detection elements juxtaposed along the moving direction, and the third element includes a connection between the second output terminal and the first power supply terminal. Each of the first detection elements and the third detection elements is connected to the first surface of the first surface. When moving in the moving direction along the scale, a predetermined readout signal is generated according to the opposing position of the scale, and the arrangement of the plurality of first detection elements in the moving direction is the first 2 ^k order term component of at least phase of the voltage signal appearing at the output terminal and the 2 ^k + ^{k + 1 ·} N order term component (the number k is chosen among any natural number, N are positive integers) rest, the first 2 from the voltage signal at least a phase appearing at the output terminal of the ^m-order term component and 2 ^m +2 ^{An m + 1} · Nth order component (m is a positive integer smaller than k) is determined to be removed, and the arrangement of the plurality of third detection elements in the moving direction is a voltage signal appearing at the second output terminal. At least the phase 2 ^k order component and the 2 ^k +2 ^{k + 1} · N order term component remain, and at least the phase 2 ^m order component and 2 ^m +2 ^{m + 1} · N order term component are removed from the voltage signal appearing at the second output terminal. The position acquisition means calculates the position of the object to be detected based on the voltage signal appearing at the first output terminal and the voltage signal appearing at the second output terminal. Characteristic To. According to this, the 2 ^k order harmonic becomes the fundamental wave. Therefore, it is possible to obtain a resolution of 2 ^k times as compared with the conventional position detecting device.

In the position detection device, the arrangement of the plurality of first detection elements in the moving direction also removes the 2 ^k +2 ^{k + 1} · Nth order component of the phase from the voltage signal appearing at the first output terminal. The arrangement of the plurality of third detection elements in the moving direction is determined so that the 2 ^k +2 ^{k + 1} · Nth-order component of the phase is also removed from the voltage signal appearing at the second output terminal. It is good as well. According to this, higher harmonics than the fundamental wave can be appropriately removed.

According to still another aspect of the present invention, there is provided a position detection apparatus configured to have a scale having a first surface extending along a movement direction of an object to be position-detected, movable with the object, and the first And a position acquisition means for acquiring a position of the position detection target object based on an output signal of the sensor, and the sensor is supplied with a first power supply potential. A first power supply terminal, a second power supply terminal to which a second power supply potential different from the first power supply potential is supplied, first to fourth output terminals, and the first output terminal And a first element connected between the first power supply terminal, a second element connected between the second power supply terminal and the first output terminal, and the second power supply terminal. A third connected between an output terminal and the first power supply terminal; And a fourth element connected between the second power supply terminal and the second output terminal, and a second element connected between the third output terminal and the first power supply terminal. 5 element, a sixth element connected between the second power supply terminal and the third output terminal, and a connection between the fourth output terminal and the first power supply terminal. The seventh output element, the eighth output element connected between the second power supply terminal and the fourth output terminal, and the third output terminal from the voltage signal appearing at the first output terminal. A first subtracting circuit that outputs a voltage signal obtained by subtracting a voltage signal appearing at, and a voltage signal obtained by subtracting the voltage signal appearing at the fourth output terminal from the voltage signal appearing at the second output terminal. A second subtracting circuit for outputting, wherein the first element includes the first output terminal and the first power supply terminal. A plurality of first detection elements connected in series between each other and arranged in the movement direction, wherein the third element is between the second output terminal and the first power supply terminal. And a plurality of third detection elements juxtaposed along the moving direction, and the fifth element is interposed between the third output terminal and the first power supply terminal. A plurality of fifth detection elements connected in series and juxtaposed along the moving direction, and the seventh element is connected in series between the fourth output terminal and the first power supply terminal. A plurality of seventh detection elements connected and juxtaposed along the moving direction, each of the first detection elements, each of the third detection elements, each of the fifth detection elements, and Each seventh detection element moves in the moving direction along the first surface, An arrangement for generating a predetermined readout signal in accordance with the opposing position of the scale, the arrangement of the plurality of first detection elements in the movement direction and the arrangement of the plurality of fifth detection elements in the movement direction Is determined so that at least the first-order component of the phase is removed from the output signal of the first subtracting circuit, and the arrangement of the plurality of third detection elements in the moving direction and the plurality of seventh detection elements are determined. The arrangement of the elements in the moving direction is determined so that at least the first-order component of the phase is removed from the output signal of the second subtraction circuit, and the position acquisition means includes the output signal of the first subtraction circuit, The position of the position detection object is calculated based on the output signal of the second subtracting circuit. According to this, in the case of performing a full bridge connection, it becomes possible to obtain a resolution that is at least twice that of a conventional position detection device.

In the position detection device, the second element is connected in series between the second power supply terminal and the first output terminal, and a plurality of second elements arranged in parallel along the moving direction. The fourth element includes a plurality of fourth detection elements connected in series between the second power supply terminal and the second output terminal and juxtaposed along the moving direction. The sixth element comprises a plurality of sixth detection elements connected in series between the second power supply terminal and the third output terminal and juxtaposed along the moving direction. The eighth element includes a plurality of eighth detection elements connected in series between the second power supply terminal and the fourth output terminal and juxtaposed along the moving direction. The plurality of second detection elements in the moving direction and the plurality of second detection elements 6 is arranged so that at least a first-order component of the phase is removed from the output signal of the first subtraction circuit, and the plurality of fourth detection elements are arranged in the movement direction. The arrangement and the arrangement of the plurality of eighth detection elements in the moving direction may be determined so that at least a first-order component of the phase is removed from the output signal of the second subtracting circuit. According to this, the temperature characteristics of the first to eighth elements can be made uniform.

In the position detection device, the first element includes 2 ⁿ (n is a number selected from an arbitrary natural number) first detection elements, and the third element is 2 ⁿ third detection elements, the fifth element includes 2 ⁿ fifth detection elements, and the seventh element includes 2 ⁿ seventh detection elements. Thus, the 2 ⁿ first detection elements are 1 at 2 ⁿ positions separated from each other by ± π / 2 ± π / 8... ± π / 2 ^{n + 1 in the} movement direction from the first reference position. The 2 ⁿ third detection elements are arranged in a moving direction from the first reference position in the moving direction (2i ₂ −1) π / 4 (i ₂ is selected from an arbitrary integer) number) not a one to distant third respectively ± π / 2 ± π / 8 ··· ± π / 2 n + 1 apart the 2 ⁿ position in the moving direction from a reference position Are arranged, the 2 ⁿ pieces of the fifth detector element (number i ₄ is selected from among any integer) the first from the reference position in the moving direction (2i 4 _-1) π / 2 disposed from the fifth reference position apart one on each ± π / 2 ± π / 8 ··· ± π / 2 n + 1 apart the 2 ⁿ position in the moving direction, wherein the 2 ⁿ 7 The detection element of (2i ₆ −1) π / 2 + (2i ₂ −1) π / 4 (where i ₆ is a number selected from an arbitrary integer) is away from the first reference position in the movement direction. Alternatively, one may be arranged at 2 ⁿ positions that are separated from each other by ± π / 2 ± π / 8... ± π / 2 ^{n + 1 in the} moving direction from the seventh reference position. According to this, in the case of performing a full bridge connection, it becomes possible to obtain twice the resolution as compared with the conventional position detection device.

Furthermore, in this position detection apparatus, the second element includes 2 ⁿ second detection elements, the fourth element includes 2 ⁿ fourth detection elements, 6 elements are composed of 2 ⁿ sixth detection elements, the eighth element is composed of 2 ⁿ eighth detection elements, and the 2 ⁿ second detection elements are: ± π from the first reference position in the moving direction from the second reference position that is (2i ₁ −1) π / 2 (i ₁ is a number selected from any integer) in the moving direction from the first reference position. / 2 ± π / 8, one on ··· ± π / 2 n ^{+ 1} apart the 2 ⁿ position is arranged, the 2 ⁿ pieces of the fourth detection element, the moving direction from the first reference position 4th reference position separated by (2i ₃ -1) π / 2 + (2i ₂ -1) π / 4 (i ₃ is a number selected from any integer) Disposed placed et the one by one in the movement direction in each ± π / 2 ± π / 8 ··· ± π / 2 n + 1 apart the 2 ⁿ position, the detection element of the 2 ⁿ pieces of the sixth, the ± π / 2 ± π / in the moving direction from a sixth reference position that is 2i ₅ π / 2 away from the first reference position in the moving direction (i ₅ is a number selected from an arbitrary integer). 8... ± π / 2 ^{n + 1} are arranged one by one at 2 ⁿ positions, and the 2 ⁿ eighth detection elements are moved from the first reference position to the moving direction by 2i ₇ π / ± π / 2 ± π / 8... ± in the moving direction from an eighth reference position separated by 2+ (2i ₂ −1) π / 4 (i ₇ is a number selected from an arbitrary integer) One piece may be arranged at 2 ⁿ positions that are separated by π / 2 ^{n + 1} . According to this, the temperature characteristics of the first to eighth elements can be made uniform.

In the position detection apparatus, the first element includes 2 ⁿ (n is a number selected from an arbitrary natural number), and the third element is 2 ⁿ third detection elements, the fifth element includes 2 ⁿ fifth detection elements, and the seventh element includes 2 ⁿ seventh detection elements. becomes, wherein the arrangement of the moving direction of the 2 ⁿ first detection element, and 2 ^k-order terms component (k is a number chosen from among any natural number) power following components other than 2, 2 ^k P N components selected from the following components (P is a prime number of 3 or more) are determined to be removed, and the 2 ⁿ third detection elements are the 2 ⁿ first detection elements. each element in the moving direction shift (number _{i 2} is to be selected from any ^{_{integer) (2i 2 -1) π /}} 2 k + 1 Is disposed at a position, the ^{2 n} pieces of the fifth detection element, wherein the ² each ^n-number of the first detection element in the moving direction ^{_{(2i 4 -1) π / 2}} k (i 4 is an arbitrary integer arranged several) shifted by a position selected from among the detection elements of the 2 ⁿ pieces of seventh, respectively the 2 ⁿ pieces of the first detecting element in the moving direction (2i 6 _-1) π / 2 ^k + (2i ₂ −1) π / 2 ^{k + 1} (where i ₆ is a number selected from an arbitrary integer) may be arranged at a shifted position. According to this, when full-bridge connection is performed, higher-order harmonics than the fundamental wave can be appropriately removed.

Furthermore, in this position detection apparatus, the second element includes 2 ⁿ second detection elements, the fourth element includes 2 ⁿ fourth detection elements, 6 elements are composed of 2 ⁿ sixth detection elements, the eighth element is composed of 2 ⁿ eighth detection elements, and the 2 ⁿ second detection elements are: Each of the 2 ⁿ first detection elements is arranged at a position shifted by (2i ₁ −1) π / 2 ^k (i ₁ is a number selected from an arbitrary integer) in the movement direction, ^{The n} fourth detection elements are (2i ₃ −1) π / 2 ^k + (2i ₂ −1) π / 2 ^{k + 1} (i ₃ ) in the moving direction, respectively, with respect to the 2 ⁿ first detection elements. is disposed at a position shifted by several) chosen from any integer, the detection element of the 2 ⁿ pieces of the sixth, the 2 ⁿ pieces of 2i each first detection element in the movement direction _{5 π} / 2 k ⁽ⁱ ₅ is a number selected from among an arbitrary integer) are arranged in a position shifted, the detecting element of the 2 ⁿ pieces of eighth, Each of the 2 ⁿ first detection elements is shifted by 2i ₇ π / 2 ^k + (2i ₂ −1) π / 2 ^{k + 1} (i ₇ is a number selected from an arbitrary integer) in the moving direction. It is good also as arrange | positioning at a position. According to this, the temperature characteristics of the first to eighth elements can be made uniform.

In the position detection apparatus, the first element includes 2 ⁿ (n is a number selected from any two or more natural numbers) first detection elements, and the third element Comprises 2 ⁿ third sensing elements, the fifth element comprises 2 ⁿ fifth sensing elements, and the seventh element comprises 2 ⁿ seventh sensing elements. consists detection element, wherein the 2 ⁿ first detection element, n = a if 2, further wherein the direction of movement from a first position in which the moving direction to the + [pi / 2 away from the first reference position One at each of the fifth and sixth positions separated by ± π / 4 respectively, and from the second position separated by −π / 2 from the first reference position in the moving direction and further by ± π in the moving direction, respectively. / 4, respectively, at 7th and 8th positions separated from each other, and when n ≧ 3, One on placed et the respective ± π / 16 ··· ± π / 2 n + 1 apart 2 ^n-2 pieces of position in the moving direction, the sixth respectively ± π / 16 ·· from the position in the moving direction of the · ± π ^{/ 2 n + 1} one by one to the distant ^{2 n-2} pieces of position, the first 7 ^{2 n-2} pieces which each distant ^{± π / 16 ··· ± π /} 2 n + 1 in the moving direction from the position of One at each position, one at each of 2 ⁿ⁻² positions ± π / 16... ± π / 2 ^{n + 1} apart from the eighth position in the moving direction, respectively. ^{The n} third detection elements are (2i ₂ −1) π / 8 (where i ₂ is a number selected from an arbitrary integer) in the moving direction with respect to each of the 2 ⁿ first detection elements. It arranged staggered position, the 2 ⁿ pieces of the fifth detection element, respectively the 2 ⁿ pieces of the first detecting element in the direction of movement _{2i 4 -1) π / 4 (} i 4 is disposed at a position shifted by several) chosen from any integer, the detection element of the 2 ⁿ pieces of seventh, said ^the 2 ⁿ first Each detection element is arranged at a position shifted in the moving direction by (2i ₆ −1) π / 4 + (2i ₂ −1) π / 8 (i ₆ is a number selected from an arbitrary integer). Also good. According to this, when full-bridge connection is performed, it becomes possible to obtain a resolution four times that of a conventional position detection device.

Furthermore, in this position detection apparatus, the second element includes 2 ⁿ second detection elements, the fourth element includes 2 ⁿ fourth detection elements, 6 elements are composed of 2 ⁿ sixth detection elements, the eighth element is composed of 2 ⁿ eighth detection elements, and the 2 ⁿ second detection elements are: Each of the 2 ⁿ first detection elements is arranged at a position shifted by (2i ₁ −1) π / 4 (i ₁ is a number selected from an arbitrary integer) in the movement direction, and the 2 ⁿ fourth detection element pieces, the ^two respective ⁿ first detector element in the moving direction _{(2i 3 -1) π / 4} + (2i 2 -1) π / 8 (i 3 is an arbitrary integer arranged several) shifted by a position selected from among the detection elements of the 2 ⁿ pieces of the sixth, the 2 ⁿ pieces of the first detection element 2i ₅ π / 4 to respectively to the moving direction (i ₅ is a number selected from among an arbitrary integer) are arranged in a position shifted, the detecting element of the 2 ⁿ pieces of the eighth, the 2 ⁿ Each of the first detection elements is arranged at a position shifted by 2i ₇ π / 4 + (2i ₂ −1) π / 8 (i ₇ is a number selected from an arbitrary integer) in the moving direction. It is good. According to this, the temperature characteristics of the first to eighth elements can be made uniform.

According to still another aspect of the present invention, there is provided a position detection apparatus configured to have a scale having a first surface extending along a movement direction of an object to be position-detected, movable with the object, and the first And a position acquisition means for acquiring a position of the position detection target object based on an output signal of the sensor, and the sensor is supplied with a first power supply potential. A first power supply terminal, a second power supply terminal to which a second power supply potential different from the first power supply potential is supplied, first to fourth output terminals, and the first output terminal And a first element connected between the first power supply terminal, a second element connected between the second power supply terminal and the first output terminal, and the second power supply terminal. A third element connected between the output terminal and the first power supply terminal. A fourth element connected between the second power supply terminal and the second output terminal, and a fifth element connected between the third output terminal and the first power supply terminal. A sixth element connected between the second power terminal and the third output terminal, and a fourth power terminal connected between the fourth output terminal and the first power terminal. Appears at the third output terminal from a voltage signal appearing at the seventh element, the eighth element connected between the second power supply terminal and the fourth output terminal, and the first output terminal A first subtracting circuit for outputting a voltage signal obtained by subtracting the voltage signal, and a voltage signal obtained by subtracting the voltage signal appearing at the fourth output terminal from the voltage signal appearing at the second output terminal. A second subtracting circuit, wherein the first element is between the first output terminal and the first power supply terminal. A plurality of first detection elements connected in series and juxtaposed along the moving direction, wherein the third element is connected in series between the second output terminal and the first power supply terminal. A plurality of third detection elements connected and juxtaposed along the moving direction, wherein the fifth element is connected in series between the third output terminal and the first power supply terminal; And a plurality of fifth detection elements juxtaposed along the moving direction, wherein the seventh element is connected in series between the fourth output terminal and the first power supply terminal. And a plurality of seventh detection elements juxtaposed along the moving direction, the first detection elements, the third detection elements, the fifth detection elements, and the first detection elements. Each of the seven detection elements moves in the movement direction along the first surface, and A plurality of first detection elements arranged in the movement direction and the plurality of fifth detection elements arranged in the movement direction; , At least the 2 ^k order component of the phase and the 2 ^k +2 ^{k + 1} · N order component (k is a number selected from an arbitrary natural number, N is a positive integer) remain in the output signal of the first subtraction circuit, It is determined that at least the 2 ^m order component and the 2 ^m +2 ^{m + 1} · N order component (m is a positive integer smaller than k) of the phase are removed from the voltage signal appearing at the first output terminal. The arrangement of the three detection elements in the movement direction and the arrangement of the plurality of seventh detection elements in the movement direction include at least a 2 ^k- order component of phase and 2 ^k +2 ^{k + 1 in} the output signal of the second subtraction circuit.・ Nth order component is Ri, from the voltage signal appearing at the second output terminal of at least 2 ^m order term component and 2 ^m +2 ^m + ^{1 · N} order term component of the phase is determined to be removed, the position acquiring means of the first subtractor circuit The position of the position detection target object is calculated based on the output signal and the output signal of the second subtracting circuit. According to this, in the case of performing a full bridge connection, it becomes possible to obtain a resolution of 2 ^k times as compared with the conventional position detection device.

In the position detection device, the arrangement of the plurality of first detection elements in the movement direction and the arrangement of the plurality of fifth detection elements in the movement direction are determined from the output signal of the first subtraction circuit. 2 ^k +2 ^{k + 1} · Nth order component is also removed, and the arrangement of the plurality of third detection elements in the movement direction and the arrangement of the plurality of seventh detection elements in the movement direction are: It may be determined so that the 2 ^k +2 ^{k + 1} · N-order component of the phase is also removed from the output signal of the second subtracting circuit. According to this, when full-bridge connection is performed, higher-order harmonics than the fundamental wave can be appropriately removed.

According to the present invention, the second and higher harmonics become the fundamental wave. Therefore, it is possible to obtain a resolution that is at least twice that of the conventional position detection device. In addition, when the present invention is applied to a position detection device using magnetism, even if a GMR element that can obtain only half the resolution of an AMR element is used, it is possible to obtain a resolution equal to or higher than the conventional one. Therefore, a GMR element can be used as the detection element.

(A) is a figure which shows the structure of the position detection apparatus by the 1st Embodiment of this invention. (B) is a figure which shows the electrical connection form of the 1st thru | or 4th element by the 1st Embodiment of this invention. (A) is a figure which shows arrangement | positioning of the GMR element which comprises the 1st element by the 1st Embodiment of this invention. (B) is a figure which shows arrangement | positioning of the GMR element which comprises the 2nd element by the 1st Embodiment of this invention. It is a figure which shows arrangement | positioning of the GMR element which comprises the 3rd and 4th element by the 1st Embodiment of this invention. (A) is a figure which shows the 1st modification of the position detection apparatus by the 1st Embodiment of this invention. (B) is a figure which shows the 2nd modification of the position detection apparatus by the 1st Embodiment of this invention. It is a figure which shows the electrical connection form of the 1st thru | or 4th element in the position detection apparatus by the 2nd Embodiment of this invention. (A) is a figure which shows arrangement | positioning of the GMR element which comprises the 1st element by the 2nd Embodiment of this invention. (B) is a figure which shows arrangement | positioning of the GMR element which comprises the 2nd element by the 2nd Embodiment of this invention. It is a figure which shows arrangement | positioning of the GMR element which comprises the 3rd and 4th element by the 2nd Embodiment of this invention. (A) and (b) are figures which show the modification of the position detection apparatus by the 2nd Embodiment of this invention. It is a figure which shows the position of the GMR element in the case of using a secondary harmonic as a fundamental wave. (A) is a figure which shows arrangement | positioning of the GMR element which comprises a 1st element in the position detection apparatus by the 3rd Embodiment of this invention. (B) is a figure which shows arrangement | positioning of the GMR element which comprises a 2nd element in the position detection apparatus by the 3rd Embodiment of this invention. It is a figure which shows arrangement | positioning of the GMR element which comprises the 3rd and 4th element in the position detection apparatus by the 3rd Embodiment of this invention. It is a figure which shows the position of the GMR element in the case of using a 4th harmonic as a fundamental wave. It is a figure which shows the modification of the position of the GMR element in the case of using a secondary harmonic as a fundamental wave. (A) is a figure which shows the structure of the position detection apparatus by the 4th Embodiment of this invention. (B) is a figure which shows the electrical connection form of the 1st thru | or 8th element by the 4th Embodiment of this invention. (A) is a figure which shows the specific example of arrangement | positioning of the GMR element in the case of setting n = 1 in the 4th Embodiment of this invention. (B) is a figure which shows the specific example of arrangement | positioning of the GMR element in case n = 2 in the 4th Embodiment of this invention. It is a figure which shows the modification of the position of the GMR element in the case of using a 4th harmonic as a fundamental wave. It is a figure which shows the modification of arrangement | positioning of the GMR element shown to Fig.2 (a) (b). It is a figure which shows the example which applied the arrangement | positioning of the GMR element similar to FIG. 9 to the cyclic | annular encoder. It is a figure which shows the example which applied arrangement | positioning of the GMR element similar to FIG. 12 to the cyclic | annular encoder. It is a figure which shows the example which applied the arrangement | positioning of the GMR element similar to FIG. 13 to the cyclic | annular encoder. It is a figure which shows the example which applied the arrangement | positioning of the GMR element similar to FIG. 16 to the cyclic | annular encoder. It is a figure which shows the example which applied the arrangement | positioning of the GMR element similar to each of Fig.15 (a) (b) to the cyclic | annular encoder. (A) is a figure which shows the structure of the position detection apparatus by the background art of this invention. (B) is a figure which shows the specific connection form of the AMR element by the background art of this invention. It is a figure which shows the change of the resistance value of each AMR element and the output signal of a magnetic sensor when the object of a position detection object moves to a x direction in the position detection apparatus by the background art of this invention. It is a figure which shows the specific connection form of each AMR element at the time of applying a full bridge connection to the magnetic sensor by the background art of this invention.

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

FIG. 1A is a diagram showing a configuration of the position detection apparatus 1 according to the first embodiment of the present invention. The position detection device 1 is a magnetic position detection device, and extends in the x direction (moving direction of the object) with a magnetic sensor 2 attached to an object (not shown) as a position detection target, as shown in FIG. A magnetic scale 3 having a surface 3a and magnetized so that N poles and S poles appear alternately along the x direction on the surface 3a; and an object of position detection based on an output signal of the magnetic sensor 2. and a position acquisition unit 9 (position acquisition means) for acquiring a position in the x direction.

FIG. 1A also shows the strength of the magnetic field formed by the magnetic scale 3. As shown in the figure, the strength of the magnetic field formed by the magnetic scale 3 is expressed as a sine wave having a wavelength of 2λ, where λ is the width (length in the x direction) of each magnetic pole appearing on the surface 3a of the magnetic scale 3. Approximated. That is, it is preferable that the magnetic scale 3 itself has periodicity with respect to the strength of the magnetic field.

The magnetic sensor 2 includes first to fourth elements 4 _A to 4 _D. In FIG. 1 (a), these are drawn as if they are arranged in the x direction, but this drawing is for convenience, and the actual arrangement of the first to fourth elements 4 _A to 4 _D Is different. The actual arrangement will be described in detail later.

FIG. 1B is a diagram showing an electrical connection form of the first to fourth elements 4 _A to 4 _D. As shown in the figure, in the present embodiment, the first to fourth elements 4 _A to 4 _D are each composed of two GMR elements. Specifically, the first element _{4 A} is composed by two GMR elements _{5 A1, 5 A2} (two of the first detection element), the second element _{4 B} is two GMR elements _{5 B1} , 5 _B2 (two second detection elements), and the third element 4 _C is constituted by two GMR elements 5 _C1 , 5 _C2 (two third detection elements), element _{4 D} of constituted by two GMR elements _{5 D1, 5 D2} (2 pieces of fourth detection elements).

Similar to the AMR element, the GMR element is an element whose resistance value changes depending on the strength of the applied magnetic field. In normal usage, the GMR element is placed so that the pin direction (P direction shown in FIG. 1A) is parallel to the normal direction of the surface 3a, so that the GMR element is along the surface 3a. When moving in the x direction, the resistance value changes according to the facing position of the magnetic scale 3. When the GMR element moves in the x direction, the wavelength of the change in the resistance value (read signal) of the GMR element is 2λ as shown in FIG. This is twice that of the AMR element (see FIG. 23A). When the readout signal of the GMR element is shown using Fourier series expansion, the following equation (16) is obtained. Where R is the resistance value of the GMR element, φ = 2π · x / 2λ, and A ₀ , A ₁ ,... Are constants.

Here, in general, the Fourier series expansion of a periodic signal is the sum of a sine term and a cosine term as in the following equation (17). On the other hand, in the equation (16) and each equation described later, the readout signal is expressed using only the sine term. This is because the read signal is an odd function.

As shown in FIG. 1B, the magnetic sensor 2 includes a power supply terminal 6 (first power supply terminal) to which a ground potential (first power supply potential) is supplied and a power supply potential Vcc (second power supply potential). Power supply terminal 7 (second power supply terminal) and two output terminals 8a and 8b (first and second output terminals). The GMR elements 5 _A1 and 5 _A2 are connected in series between the output terminal 8 a and the power supply terminal 6 in this order. Similarly, the GMR elements 5 _B1 and 5 _B2 are connected in series between the power supply terminal 7 and the output terminal 8 a in this order, and the GMR elements 5 _C1 and 5 _C2 are connected in this order to the output terminal 8 b and the power supply terminal 6. The GMR elements 5 _D1 and 5 _D2 are connected in series between the power supply terminal 7 and the output terminal 8 b in this order. The voltage signal appearing at the output terminal 8a becomes one output signal Vsin of the magnetic sensor 2, and the voltage signal appearing at the output terminal 8b becomes the other output signal Vcos of the magnetic sensor 2. Note that the order of connection of the plurality of GMR elements constituting the element may be in any order. For example, the order of connection of the GMR elements 5 _A1 and 5 _A2 may be reversed.

With the above configuration, the output signals Vsin and Vcos are expressed by the following equations (18) and (19), respectively. However, R _X (x is A1, A2, etc.) is the resistance value of the GMR element 5 _X. As shown in these equations, the numerator of the output signal Vsin is a sum signal of the read signals of the GMR elements constituting the first element, and the numerator of the output signal Vcos is the sum of the GMR elements constituting the third element. This is the sum signal of the read signals. The denominator of the output signal Vsin is a sum signal of the read signals of the GMR elements constituting the first and second elements, and the denominator of the output signal Vcos is the read of the GMR elements constituting the third and fourth elements. It becomes the sum signal of the signal.

The physical arrangement of each GMR element is such that when the output signals Vsin and Vcos are calculated, odd-order harmonics including the first-order component of φ are removed, and second-order harmonics (second-order component of φ) are basically used. Decided to be a wave. Hereinafter, a specific arrangement of each GMR element will be described.

FIG. 2A is a diagram showing the arrangement of the GMR elements 5 _A1 and 5 _A2 . As shown in the figure, when the position of x = B ₁ is set as a reference position (first reference position), the GMR element 5 _A1 is separated from the first by + π / 2 (= + λ / 2) in the x direction. Is located at position P ₁ (= B ₁ + λ / 2). The GMR element 5 _A2 is disposed at a second position P ₂ (= B ₁ -λ / 2) that is −π / 2 (= −λ / 2) away from the first reference position B _{1 in the} x direction. The

FIG. 2B is a diagram showing the arrangement of the GMR elements 5 _B1 and 5 _B2 . As shown in the figure, the GMR element 5 _B1 uses the position of x = B ₂ as a reference position (second reference position), and is separated from the third position by + π / 2 (= + λ / 2) in the x direction. It is disposed at a position _{P 3 (= B 2 + λ} / 2). The second reference position B ₂ is here set to the first reference from the position B ₁ in the x-direction + π / 2 (= + λ / 2) ( third predetermined distance) away. The GMR element 5 _B2 is disposed at a _fourth position P ₄ (= B ₂ −λ / 2) that is separated from the second reference position B ₂ by −π / 2 (= −λ / 2) in the x direction.

As a result of arranging each GMR element as described above, the read signals of the GMR elements 5 _A1 , 5 _A2 , 5 _B1 , and 5 _B2 are expressed by the following equations (20) to (23), respectively.

Substituting Equations (20) to (23) into Equation (18), the output signal Vsin is obtained as in the following Equation (24).

As understood from the equation (24), in the output signal Vsin according to the present embodiment, odd-order harmonics including the first-order component of φ disappear, and second-order harmonics (second-order component of φ) are fundamental. It has become a wave.

FIG. 3 is a diagram showing the arrangement of the GMR elements 5 _C1 , 5 _C2 , 5 _D1 and 5 _D2 . As shown in the figure, the GMR elements 5 _C1 , 5 _C2 , 5 _D2 , and 5 _D2 are respectively connected to the GMR elements 5 _A1 , 5 _A2 , 5 _B1 , and 5 _B2 by a predetermined distance + λ / 4 (= + π / 4) in the x direction. ). The predetermined distance is not limited to + λ / 4, and may be determined so that the phase of the output signal Vcos differs by an odd multiple of π / 2 compared to the phase of the output signal Vsin. Further, the predetermined distance (first predetermined distance) for the GMR elements 5 _C1 and 5 _{C2 and} the predetermined distance (second predetermined distance) for the GMR elements 5 _D2 and 5 _D2 may be different. As a result, the read signals of the GMR elements 5 _C1 , 5 _C2 , 5 _D1 , and 5 _D2 are expressed as the following Expressions (25) to (28), respectively.

Substituting Expressions (25) to (28) into Expression (19), the output signal Vcos is obtained as in the following Expression (29).

As understood from the equation (29), even in the output signal Vcos, the odd-order harmonics including the first-order component of φ disappear, and the second-order harmonic (second-order component of φ) becomes the fundamental wave. Yes.

The position acquisition unit 9 uses the output signals Vsin and Vcos obtained as described above to calculate the position in the x direction of the object that is the position detection target. Specifically, the position x of the object is calculated by the following equation (30).

As described above, in the position detection apparatus 1 according to the present embodiment, the second harmonic becomes the fundamental wave. Therefore, the position detection apparatus 1 according to the present embodiment realizes twice the resolution as compared with the conventional position detection apparatus. From another point of view, the same resolution as that obtained when the AMR elements shown in the equations (12) and (13) are used although the GMR elements are used. Therefore, according to the position detection device 1, it is possible to use a GMR element as a detection element for the position detection device.

FIG. 4A is a diagram illustrating a first modification of the position detection device 1 according to the first embodiment. In the present modification, as shown in the figure, the second and fourth elements 4 _B and 4 _D are configured by resistance elements configured not to be affected by the magnetic field formed by the magnetic scale 3. The “resistive element configured so as not to be affected by the magnetic field formed by the magnetic scale 3” may be a resistive element that does not have a magnetoresistive effect, or from a magnetic field formed by the magnetic scale 3. It may be a GMR element disposed at a magnetically shielded location. The output signals Vsin and Vcos in this case are obtained as in the following equations (31) and (32), where R _S is the resistance of the second and fourth elements 4 _B and 4 _D.

As understood from the equations (31) and (32), even in the output signals Vsin and Vcos according to this modification, the odd-order harmonics including the first-order component of φ disappear, and the second-order harmonics (φ The quadratic component is the fundamental wave. Therefore, it is possible to use a GMR element as a detection element for the position detection device.

In the case where the second and fourth elements 4 _B and 4 _D are configured by GMR elements disposed at locations magnetically shielded from the magnetic field formed by the magnetic scale 3, the first and third elements The temperature characteristics of the elements 4 _A and 4 _C and the second and fourth elements 4 _B and 4 _D can be made uniform. However, since it is necessary to shield magnetically, the first and third elements 4 _A and 4 _D and the second and fourth elements 4 _B and 4 _D may not be configured as an integrated circuit. There is. Therefore, when it is necessary to make these into an integrated circuit and to make these temperature characteristics uniform, it is preferable to use the position detection device 1 according to the first embodiment.

FIG. 4B is a diagram illustrating a second modification of the position detection device 1 according to the first embodiment. In the present modification, as shown in the figure, the second and fourth elements 4 _B and 4 _D are constituted by constant current sources. The output signals Vsin and Vcos in this case are obtained as shown in the following equations (33) and (34), where I _S is the current generated by the second and fourth elements 4 _B and 4 _D.

As understood from the equations (33) and (34), even in the output signals Vsin and Vcos according to this modification, the odd-order harmonics including the first-order component of φ disappear, and the second-order harmonics (φ The quadratic component is the fundamental wave. Therefore, it is possible to use a GMR element as a detection element for the position detection device. Moreover, if the wiring between elements becomes long, the wiring resistance may not be negligible. In such a case, it is preferable to use a constant current source.

FIG. 5 is a diagram showing an electrical connection form of the first to fourth elements 4 _A to 4 _D in the position detection apparatus 1 according to the second embodiment of the present invention. The position detection apparatus 1 according to the present embodiment is different from the position detection apparatus 1 according to the first embodiment in that the first to fourth elements 4 _A to 4 _D are each composed of four GMR elements. The other points are common. Hereinafter, the position detection apparatus 1 according to the present embodiment will be described focusing on the differences.

As shown in FIG. 5, in the present embodiment, the first element 4 _A is composed of four GMR elements 5 _A1 to 5 _A4 (four first detection elements), and the second element 4 _B Is constituted by four GMR elements 5 _B1 to 5 _B4 (four second detection elements), and the third element 4 _C includes four GMR elements 5 _C1 to 5 _C4 (four third detection elements). The fourth element 4 _D is composed of four GMR elements 5 _D1 to 5 _D4 (four fourth detection elements).

As shown in FIG. 5, GMR elements 5 _A1 to 5 _A4 are connected in series between output terminal 8a and power supply terminal 6 in this order, and GMR elements 5 _B1 to 5 _B4 are connected to power supply terminal 7 in this order. The GMR elements 5 _C1 to 5 _C4 are connected in series between the output terminal 8a, the GMR elements 5 _C1 to 5 _C4 are connected in series between the output terminal 8 b and the power supply terminal 6, and the GMR elements 5 _D1 to 5 _D4 are connected in this order. The power supply terminal 7 and the output terminal 8b are connected in series. With the above connection, the output signals Vsin and Vcos are expressed by the following equations (35) and (36), respectively.

As with the first embodiment, the physical arrangement of each GMR element is such that when the output signals Vsin and Vcos are calculated, the odd-order harmonics including the first-order component of φ are removed, and the second-order harmonics ( The second-order term component of φ is determined to be a fundamental wave. In addition, in the present embodiment, it is determined so as to remove fourth-order harmonics (fourth-order component of φ). Hereinafter, a specific arrangement of each GMR element will be described.

FIG. 6A is a diagram showing the arrangement of GMR elements 5 _A1 to 5 _A4 . As shown in the figure, the GMR element 5 _A1 is located at a position (= B ₁ ) away from the second position P ₂ (= B ₁ −λ / 2) described above by + π / 8 (= + λ / 8) in the x direction. -3λ / 8). The GMR element 5 _A2 is disposed at a position (= B ₁ -5λ / 8) that is separated from the second position P ₂ by −π / 8 (= −λ / 8) in the x direction. The GMR element 5 _A3 is disposed at a position (= B ₁ + 5λ / 8) that is separated from the first position P ₁ (= B ₁ + λ / 2) by + π / 8 (= + λ / 8) in the x direction. Is done. Further, the GMR element 5 _A4 is disposed at a position (= B ₁ + 3λ / 8) that is separated from the first position P ₁ by −π / 8 (= −λ / 8) in the x direction.

Next, FIG. 6B is a diagram showing the arrangement of the GMR elements 5 _B1 to 5 _B4 . As shown in the figure, the GMR element 5 _B1 is located at a position (= B ₂ + 5λ) that is separated from the above-described third position P ₃ (= B ₁ + λ / 2) by + π / 8 (= + λ / 8) in the x direction. / 8). The GMR element 5 _B2 is disposed at a position (= B ₂ + 3λ / 8) that is separated from the third position P ₃ by −π / 8 (= −λ / 8) in the x direction. Further, the GMR element 5 _B3 is located at a position (= B ₂ −3λ / 8) that is separated from the above-described fourth position P ₄ (= B ₂ −λ / 2) by + π / 8 (= + λ / 8) in the x direction. Placed in. The GMR element 5 _B4 is disposed at a position (= B ₂ −5λ / 8) that is separated from the fourth position P ₄ by −π / 8 (= −λ / 8) in the x direction.

Next, FIG. 7 is a diagram showing the arrangement of the GMR elements 5 _C1 to 5 _C4 and 5 _D1 to 5 _D4 . As shown in the figure, the GMR elements 5 _C1 to 5 _C4 , 5 _D1 to 5 _D4 are respectively connected to the GMR elements 5 _A1 to 5 _A4 and 5 _B1 to 5 _B4 by a predetermined distance + λ / 4 (= + π / 4) in the x direction. ). Again, this predetermined distance is not limited to + λ / 4, and it may be determined so that the phase of the output signal Vcos differs from the phase of the output signal Vsin by an odd multiple of π / 2. Further, the predetermined distance (first predetermined distance) for GMR elements 5 _C1 to 5 _{C4 and} the predetermined distance (second predetermined distance) for GMR elements 5 _D1 to 5 _D4 may be different.

When the read signals of the respective GMR elements are calculated based on the above-described arrangement and are substituted into the equations (35) and (36) to obtain the output signals Vsin and Vcos, the output signals Vsin and Vcos are expressed by the following equations ( 37) and equation (38).

As understood from the equations (37) and (38), even in the output signals Vsin and Vcos according to the present embodiment, the odd-order harmonics including the first-order component of φ disappear, and the second-order harmonics (φ Of the second-order term) is the fundamental wave. Therefore, the position detection device 1 according to the present embodiment also achieves twice the resolution as compared with the conventional position detection device. In addition, in the present embodiment, fourth-order harmonics (fourth-order component of φ) are also removed. Therefore, it is possible to obtain the position x more accurately than in the first embodiment.

FIGS. 8A and 8B are diagrams showing a modification of the position detection device 1 according to the second embodiment. This modification, the second reference position B _2, in the x-direction from the first reference position _{B 1 + 3π / 2 (=} + 3λ / 2) in that set to a position apart, the second embodiment It is different from the form. Also by this modification, the same effect as the second embodiment is obtained.

Thus, not the distance between the first reference position B ₁ of the second reference position B ₂ must always π / 2 (= λ / 2 ), lπ / 2 (l is an odd number) If it is.

Here, a generalized description will be given of the arrangement of the GMR element in the case where the second harmonic is used as the fundamental wave. In the following description focuses on the first element 4 _A, select the first element 4 _A is, 2 ⁿ pieces (n connected in series between the output terminal 8a and the power supply terminal 6 from among any natural number The number of GMR elements will be described. The same generalization can be applied to the second element 4 _B by changing B ₁ , P ₁ , and P ₂ to B ₂ , P ₃ , and P ₄ in the following description.

FIG. 9 is a diagram showing the position of the GMR element in each case of n = 1 to 4. As shown in the drawing, first the case of n = 1 (if the first element _{4 A} is composed of two GMR element), the two GMR elements, respectively, from the first reference position _{B 1} in the x-direction to ± [pi / 2 apart first and second positions _P 1, _{P 2,} are arranged one by one.

In the present invention, for example, when using the expression “eight positions apart from X ₁ by ± X ₂ ± X ₃ ± X ₄ ” (X ₁ to X ₄ are positions on the x axis), X ₁ + X ₂ + X ₃ + X ₄ + 2π · i, X ₁ + X ₂ + X ₃ −X ₄ + 2π · i, X ₁ + X ₂ −X ₃ + X ₄ + 2π · i, X ₁ + X ₂ −X ₃ −X ₄ + 2π · i, X ₁ -X ₂ + X ₃ + X ₄ + 2π · i, X ₁ -X ₂ + X ₃ -X ₄ + 2π · i, X ₁ -X ₂ -X ₃ + X ₄ + 2π · i, and X ₁ -X ₂ -X ₃ -X _It means 8 positions of ₄ + 2π · i. However, i is an arbitrary integer and may be a different value for each detection element. The reason why 2π · i is added is that the output of the GMR element is the same at a certain position and a position away from 2π · i. This is because the waveform of the output signal of the GMR element becomes a waveform depending on the period of the magnetic field. According to the above definition, the first position P ₁ is a position separated from the first reference position B ₁ by + π / 2 + 2π · i in the x direction, and the second position P ₂ is the first reference position B 1. _{It is} a position away from _{1 in the} x direction by −π / 2 + 2π · i.

Then in the case of n ≧ 2, the one at first respective ± [pi / 8 from the position _{P 1} in the x direction ··· ± π ^{/ 2 n + 1} apart ^{2 n-1} positions GMR element together they are placed, one by one to the second, respectively ± [pi / 8 from the position _{P 2} in the x direction ··· ± π ^{/ 2 n + 1} apart ^{2 n-1} positions GMR elements are arranged.

When again it is described for each value of n, when n = 2, speaking from a first position P _1, respectively ± [pi / 8 distant two positions (more generally in the x-direction, a first position a position apart in the x-direction π / 8 + 2π · i from _{P 1, -π / 8 + 2π} · i away. the same applies hereinafter. 1 to) each GMR element is arranged in the x direction from the first position _{P 1} together, GMR elements one by one is disposed to two positions away respectively ± [pi / 8 in x-direction from the second position P _2. n = in the case of 3, together with one by one from the first position P ₁ to the four positions away respectively ± π / 8 ± π / 16 in the x-direction GMR element is disposed, a second position P One GMR element is also arranged at four positions spaced from each other by _{2 in the} x direction by ± π / 8 ± π / 16. In the case of n = 4, together with the one by one from the first position P ₁ to the respective ± π / 8 ± π / 16 ± π / 32 distant eight positions in the x-direction GMR element is disposed, the one by one from the second position P _2, respectively ± π / 8 ± π / 16 ± π / 32 distant eight positions in the x-direction GMR element is arranged.

By adopting the above arrangement, as described in the first and second embodiments, odd-order harmonics including the first-order component of φ disappear, and second-order harmonics (φ2 Next-order component) can be used as the fundamental wave. Further, when n ≧ 2, the 4th harmonic is further removed, when n ≧ 3, the 8th harmonic is further removed, and when n ≧ 4, the 16th harmonic is further removed. , N is larger, the position x can be obtained more accurately.

In general, the following relationship exists between the arrangement of the GMR element and the harmonics to be removed. That is, one GMR element is placed at 2 ⁿ positions separated by ± π / Y ₁ ± π / Y ₂ ± π / Y ₃ ... ± π / Y _{n in the} x direction from the first reference position B _1. When arranged, Y ₁ / second order, Y ₂ / second order, Y ₃ / second order,... Y _n / second order waves are removed. For example, in the case of n = 4 in FIG. 9, Y ₁ = 2, Y ₂ = 8, Y ₃ = 16, and Y ₄ = 32, so 2/2 = 1 order, 8/2 = 4 order, The waves of 16/2 = 8th order and 32/2 = 16th order are removed.

Next, a position detection apparatus 1 according to a third embodiment of the present invention will be described. The position detection apparatus 1 according to the present embodiment is common to the position detection apparatus 1 according to the second embodiment in that the first to fourth elements 4 _A to 4 _D are each composed of four GMR elements. However, it differs from the position detection apparatus 1 according to the second embodiment in the physical arrangement of each GMR element. Specifically, the physical arrangement of each GMR element according to the present embodiment is such that when the output signals Vsin and Vcos are calculated, in addition to the odd-order harmonics including the first-order component of φ, the second-order harmonics are included. (Second-order component of φ) is also removed, and the fourth-order harmonic (fourth-order component of φ) is determined to be a fundamental wave. Hereinafter, the position detection apparatus 1 according to the present embodiment will be described focusing on the differences.

FIG. 10A is a diagram showing the arrangement of the GMR elements 5 _A1 to 5 _A4 in the position detection apparatus 1 according to the present embodiment. As shown in the figure, the GMR element 5 _A1 in the present embodiment is separated from the above-described first position P ₁ (= B ₁ + λ / 2) by + π / 4 (= + λ / 4) in the x direction. It is arranged at the fifth position P ₅ (= B ₁ + 3λ / 4). The GMR element 5 _A2 is disposed at a _sixth position P ₆ (= B ₁ + λ / 4) that is separated from the first position P ₁ by −π / 4 (= −λ / 4) in the x direction. Further, the GMR element 5 _A3 has a seventh position P ₇ (= B ₁ ) that is separated from the second position P ₂ (= B ₁ -λ / 2) by + π / 4 (= + λ / 4) in the x direction. -Λ / 4). Further, the GMR element 5 _A4 is arranged at an _eighth position P ₈ (= B ₁ -3λ / 4) that is separated from the second position P ₂ by −π / 4 (= −λ / 4) in the x direction. .

FIG. 10B is a diagram showing the arrangement of the GMR elements 5 _B1 to 5 _B4 in the position detection device 1 according to the present embodiment. As shown in the figure, in this embodiment, the second reference position B ₂ is set to the first from the reference position B ₁ in the x-direction + π / 4 (= + λ / 4) away.

The distance between the first reference position B ₁ of the second reference position B ₂ is generally an odd multiple of [pi / 2 ^k if the fundamental wave is 2 ^k harmonic . In the first and second embodiments, since the fundamental wave is 2 harmonic, the distance between the first reference position B ₁ of the second reference position B ₂ is an odd multiple of [pi / 2 there were. In contrast, in the present embodiment, since the order of the fundamental wave is 4, the distance between the first reference position B ₁ of the second reference position B ₂ is an odd multiple of [pi / 4.

The GMR element 5 _B4 has a ninth position P ₉ (= B ₂ + 3λ / 4) that is separated from the third position P ₃ (= B ₂ + λ / 2) by + π / 4 (= + λ / 4) in the x direction. ). The GMR element 5 _B3 is disposed at a _tenth position P ₁₀ (= B ₂ + λ / 4) that is separated from the third position P ₃ by −π / 4 (= −λ / 4) in the x direction. Further, the GMR element 5 _B2 has an eleventh position P ₁₁ (= B ₂ −λ) that is separated from the fourth position P ₄ (= B ₂ −λ / 2) by + π / 4 (= + λ / 4) in the x direction. / 4). Further, the GMR element 5 _B1 is disposed at a _twelfth position P ₁₂ (= B ₂ -3λ / 4) which is separated from the fourth position P ₄ by −π / 4 (= −λ / 4) in the x direction. .

FIG. 11 is a diagram showing an arrangement of the GMR elements 5 _C1 to 5 _C4 and 5 _D1 to 5 _{D4 in} the position detection apparatus 1 according to the present embodiment. As shown in the figure, the GMR elements 5 _C1 to 5 _C4 , 5 _D1 to 5 _D4 are respectively connected to the GMR elements 5 _A1 to 5 _A4 and 5 _B1 to 5 _B4 by a predetermined distance + λ / 8 (= + π / 8) in the x direction. ). Again, this predetermined distance is not limited to + λ / 8, and it may be determined so that the phase of the output signal Vcos differs by an odd multiple of π / 2 compared to the phase of the output signal Vsin. Further, the predetermined distance (first predetermined distance) for GMR elements 5 _C1 to 5 _{C4 and} the predetermined distance (second predetermined distance) for GMR elements 5 _D1 to 5 _D4 may be different.

When the read signals of the respective GMR elements are calculated based on the above-described arrangement and are substituted into the equations (35) and (36) to obtain the output signals Vsin and Vcos, the output signals Vsin and Vcos are expressed by the following equations ( 39) and Equation (40).

As understood from the equations (39) and (40), in the output signals Vsin and Vcos according to the present embodiment, in addition to the odd-order harmonics including the first-order component of φ, the second-order harmonics (φ Of the second-order term) is also removed, and the fourth-order harmonic (fourth-order component of φ) is the fundamental wave. Therefore, the position detection device 1 according to the present embodiment achieves a resolution four times that of the conventional position detection device.

Here, a general description will be given of the arrangement of the GMR elements in the case where the fourth harmonic is used as the fundamental wave. In the following description focuses on the first element 4 _A, the first element 4 _A is, 2 ⁿ pieces connected in series between the output terminal 8a and the power supply terminal 6 (n is an arbitrary natural number of 2 or more A description will be given assuming that the number of GMR elements is a number selected from among them. The second element 4 _B is the same by changing B ₁ , P ₁ , P ₂ , and P ₅ to P ₈ to B ₂ , P ₃ , P ₄ , and P ₉ to P ₁₂ in the following description. Generalization is applicable.

FIG. 12 is a diagram showing the position of the GMR element in each case of n = 2-4. As shown in the drawing, first the case of n = 2 (if the first element _{4 A} is composed of four GMR elements), four GMR elements, respectively, from the first reference position _{B 1} in the x-direction One by one is arranged at the _fifth to _eighth positions P ₅ to P ₈ further separated by ± π / 4 from the first and second positions P1, P2 separated by ± π / 2.

Then in the case of n ≧ 3 is one by one from the position _{P 5} of the 5 to each ^{± π / 16 ··· ± π /} 2 n + 1 apart ^{2 n-2} pieces of position in the x-direction GMR element is arranged, the sixth is arranged one not a GMR element one each ^{± π / 16 ··· ± π /} 2 n + 1 apart ^{2 n-2} pieces of position from the position _{P 6} in the x direction, the position of the 7 One GMR element is arranged at each of 2 ⁿ⁻² positions ± π / 16... ± π / 2 ^{n + 1} apart from P _{7 in the} x direction, and ± ₈ directions from the eighth position P _{8 in the} x direction. π / 16... ± π / 2 ^{n + 1} GMR elements are arranged at 2 ⁿ⁻² positions apart from each other.

By adopting the above arrangement, as described in the third embodiment, in addition to odd-order harmonics including the first-order component of φ, second-order harmonics (second-order component of φ) And the fourth-order harmonic (fourth-order component of φ) can be used as the fundamental wave. Further, when n ≧ 3, the 8th harmonic is further removed, and when n ≧ 4, the 16th harmonic is further removed. n = variable _Y 1 described above for the case of _{4, Y} 2, will be described with reference to _..., because it is _{Y 1 = 2, Y 2 =} 4, Y 3 = 16, Y 4 = 32, 2/2 = 1st order, 4/2 = 2nd order, 16/2 = 8th order, and 32/2 = 16th order. Therefore, the position x can be obtained more accurately as n increases.

As described above, according to the present invention, it is possible to use the second or fourth harmonic as the fundamental wave. Therefore, it is possible to obtain twice or four times the resolution as compared with the conventional position detecting device. From another point of view, even if a GMR element that can obtain only half the resolution of an AMR element is used, a resolution equivalent to or higher than that of the conventional one can be obtained, so that a GMR element can be used as a detection element. Become.

In the present invention, not only the second-order or fourth-order harmonics but also 2 ^k (k is a natural number) order harmonics can be the fundamental wave. Therefore, for example, by arranging the GMR element so that the 8th and 16th harmonics become the fundamental wave, higher resolution can be obtained.

On the other hand, harmonics other than the 2 ^k order cannot be fundamental waves. This is because the 2 ^k +2 ^{k + 1} · Nth order component (N is an integer satisfying N ≧ 0) is also removed by removing the 2 ^k order component. Hereinafter, this point will be described in detail.

In short, the removal of harmonics is realized by adding two signals that are shifted by a predetermined amount in the positive and negative phases of the original signal. That is, g (φ) = f (φ + ρ) + f (φ−ρ) obtained by adding the offset ± ρ added to φ in f (φ) shown in the above equation (17) is f (φ ) From which harmonics corresponding to ρ are removed.

Expression (41) represents the signal g (φ) by a mathematical expression. According to the equation (41), when a certain order m ₀ (m ₀ is a natural number) satisfies the relationship of the equation (42), the m _0th- order term component of φ is removed from the signal g (φ). This is because cos (m ₀ ρ) = 0. However, _{k 1} in the formula (42) is an integer. Conversely, if it is desired to remove the m _0th- order term component, ρ may be determined so as to satisfy Equation (42).

Here, when ρ is determined so as to satisfy Expression (42), x satisfying cos (xρ) = 0 (x is a natural number) is not only m ₀ . Specifically, all x satisfying the equation (43) satisfy cos (xρ) = 0. However, _{k 2} in the formula (43) is an integer.

If k ₁ = 0, the equation (43) can be rewritten as the following equation (44). When ρ is determined from the equation (44) such that the m _0th- order term component is removed, in addition to the m _0th- order term component, the m _Nth- order term component (N satisfies N ≧ 0) expressed by the equation (45) (Integer) is also removed at the same time.

The following Table 1 specifically lists the order m _N removed simultaneously for each value of m ₀ . As shown in this table, when ρ is determined so that the first-order term component is removed, all odd-order term components are removed. Further, when ρ is determined such that the second-order term component is removed, the sixth-order term, the 10th-order term, the 14th-order term,... Are removed. The same applies to the following.

If the smallest order among the series of orders removed at the same time is called a basic order, the basic orders are 1, 2, 4,..., 2 ^k (k is an integer satisfying k ≧ 0). Therefore, from equation (45), the order removed simultaneously when 2 ^k is the basic order is generally expressed by the following equation (46).

As described above, according to the present invention, the 2 ^k +2 ^{k + 1} · Nth order component (N is an integer satisfying N ≧ 0) is also removed by removing the 2 ^k order component.

Here, the number represented by 2 ^k (1 + 2N) appearing in the equation (46) includes a total natural number less than 2 ^{k + 1} . This means that all natural numbers are represented by products of even prime numbers (2) and odd prime numbers, (1 + 2N) represents all odd numbers (product of odd prime numbers), and 2 ^k represents products of even prime numbers. by. Therefore, if the arrangement is such that the 2 ^k order term component (0 ≦ k ≦ n) is removed first, the 2 ^{n + 1} order term component becomes the fundamental wave.

From the opposite viewpoint, it can be said that, for example, in order to use a fourth-order harmonic as a fundamental wave, it is sufficient to remove the first-order component and the second-order term component, and it is not necessary to remove the third-order term component. In other words, the arrangement of the GMR element to the fundamental harmonic of the 2 ^k order (k ≧ 1) is, 2 ^m-order terms component (m is smaller than k positive integer) sufficient to determine as is removed . The examples shown in FIG. 9 and FIG. 12 described above utilize such properties of the present invention.

However, removing only the 2 ^m order component (m is a positive integer smaller than k) may cause a problem from the viewpoint of removing higher harmonics than the fundamental wave. This will be described in detail below.

For example, in the example of n = 3 in FIG. 9, the basic orders to be removed are 1, 4, 8, and the removed orders are 1, 3, 5, 7,..., 2N + 1 order, 4,12. , 20, 28,..., 8N + 4th order, 8, 24, 40, 56,. Eventually, the components to be removed are the following components: 1, 3, 4, 5, 7, 8, 9, 11,... The 6th order component, the 10th order component and the like are not removed. In the example of n = 3 in FIG. 12, since the basic orders to be removed are 1, 2, 8, the orders to be removed are 1, 3, 5, 7,..., 2N + 1 order, 2, 6, 10, 14,..., 4N + second order, 8, 24, 40, 56,. Eventually, the removed components are 1, 2, 3, 5, 6, 7, 8, 9, 10, 11, 13,..., And the following components are not removed.

The “non-removable component” in question is, in short, the harmonic component that should be removed at the same time if the 2 ^k order used as the fundamental wave is removed, that is, the N ^{k of the} 2 ^k +2 ^{k + 1} · Nth order component. ≧ 1 part. Therefore, in order to appropriately remove the “component that is not removed”, the GMR element may be arranged so that the 2 ^k +2 ^{k + 1} · Nth order component (N ≧ 1) is removed. Hereinafter, an example will be described.

FIG. 13 is a diagram showing a modification of the position of the GMR element in the case where the second harmonic is used as the fundamental wave. As understood from a comparison between FIG. 9 and FIG. 9, the GMR element in the case of n = 1, 2 is the same as the example of FIG.

On the other hand, When n = 3, with one by one from the first position P ₁ to the four positions respectively ± π / 8 ± π / 12 apart in the x direction GMR element is disposed, a second position from P ₂ one by one in four positions respectively ± π / 8 ± π / 12 apart in the x direction GMR element is arranged. Also, when n = a 4, together with the one by one from the first position P ₁ to 8 positions away respectively ± π / 8 ± π / 12 ± π / 16 in the x-direction GMR element is disposed, GMR elements one by one is disposed to the second position P _2, respectively ± π / 8 ± π / 12 ± π / 16 distant eight positions in the x-direction from.

In short, in FIG. 13, an arrangement (± π / 12) for removing the 2 ¹ +2 ^{1 + 1} · 1 = 6th order component is inserted as compared with the example of FIG. Since this arrangement corresponds to the case where m ₀ = 6 in the equation (45), the 18th, 30th,..., 12N + 6th order components are also removed in addition to the 6th order term component. Therefore, for example, when n = 3, 1, 3, 5, 7,..., 2N + 1 order, 4, 12, 20, 28,..., 8N + 4th order, 6, 18, 30,. Each component of 12N + 6th order is removed. In summary, it is understood that the following components are removed, and that the sixth-order component is also removed.

When n = 4, 1, 3, 5, 7,..., 2N + 1 order, 4, 12, 20, 28,..., 8N + 4th order, 6, 18, 30,. Next, the 8th, 24th, 40th, 56th,..., 16N + 8th order components are removed. In summary, 1, 3, 4, 5, 6, 7, 8,... Are removed, and the sixth-order component is also removed as in the case of n = 3. Understood.

The above is an example of removing harmonics of N = 1 when k = 1, but the same applies to the case of k ≧ 2 or N ≧ 1. Specifically, as is apparent from the above description using the variables Y ₁ , Y ₂ ,..., The arrangement sequence of GMR elements is ± π / {(2 ^k +2 ^{k + 1} · N) × 2}. An arrangement of = ± π / (2 ^{k + 1} +2 ^{k + 2} · N) may be added. By doing so, it becomes possible to suitably remove higher harmonics than the fundamental wave.

In order to remove components other than the fundamental wave substantially completely, the following may be performed. When (the k number selected from among any natural number) 2 ^k-order term component as the fundamental wave is assumed to leave, firstly The basis is the arrangement capable of removing a power of two following components other than 2 ^k-order term component is there. 1 This is a plurality of positions away respectively ^{± π / 2 1 ··· ± π} / 2 k ± π / 2 k + 2 ± π / 2 k + 3 ··· in the x direction from the first reference position _{B 1} This corresponds to arranging GMR elements one by one. However, in this arrangement, if the 2 ^k order term component is removed, the component that is automatically removed, that is, 2 ^k +2 ^{k + 1} N order term component (N ≧ 1) is not removed (see Equation (46)). Needs to employ an arrangement that can remove the 2 ^k +2 ^{k + 1} Nth-order component (N ≧ 1).

Here, 2 ^k +2 ^{k + 1} N is equal to 2 ^k (2N + 1). Therefore, if an arrangement capable of removing higher harmonics corresponding to odd multiples of the fundamental wave order 2 ^k is added to the basic arrangement, components other than the fundamental wave can be completely removed. However, in this arrangement, the removed orders may overlap, which is not efficient. For example, since 2 ^k · 9 can be written as 2 ^k · 3 · (2 · 1 + 1), it is automatically removed by an arrangement that removes the 2 ^k · 3 order harmonics. An efficient arrangement that avoids such duplication is an arrangement that can remove higher-order harmonics corresponding to 2 ^k P (P is a prime number of 3 or more). In other words, if an arrangement capable of removing harmonics of the order corresponding to 2 ^kP is added to the basic arrangement, components other than the fundamental wave can be efficiently removed completely.

In reality, the number of GMR elements that can be arranged is limited. Therefore, ^if the first element 4 _A is composed of 2 ⁿ GMR elements, a power-of-two component (2 ⁰ , 2 ¹ ,..., 2 ^k−1 , 2 other than the 2 ^k order component) ^{k + 1} , 2 ^{k + 2} ,...) and 2 ^k P-order components (2 ^k · 3, 2 ^k · 5, 2 ^k · 7, 2 ^k · 11,...) An arrangement corresponding to the selected order may be adopted. In this selection, it is preferable to select a component having a large influence on the output signal. That is, as shown in the equations (24) and (29), the harmonic component having an even multiple of the fundamental wave order does not remain in the numerator of the output signal. Since such harmonic components have a small influence on the output signal, it is preferable not to select them and to preferentially select the harmonic components remaining in the molecule. To explain with a specific example, for example, if k = 1, a power order component 2 other than the ^{2 k-order} terms component ^{2 0,} 2 ^{2, 2} 3, a., Tables in ^{2 k} P The resulting components are 2 ¹ · 3, 2 ¹ · 5, 2 ¹ · 7, 2 ¹ · 11,. And the even multiple of the order 2 of the fundamental wave is 4, 8, 12,. Thus, for example, if the k = 1, n = 5, select each order of 1,6,10,14,22, arranged corresponding to these, i.e. respectively in the x direction from the first reference position _{B 1} one for ± π / 2 ± π / 12 ± π / 20 ± π / 28 ± π / 44 away, it is preferable to dispose ^{two five} GMR element.

For the second to fourth elements 4 _B to 4 _D , as shown in Table 3 to be described later, the first element 4 _A is moved in the x direction to + (2i ₁ −1) π / 2 ^k (i ₁ is Arbitrary integer) The second element 4 _B is arranged at a shifted position, and the first element 4 _A is shifted in the x direction by + (2i ₂ −1) π / 2 ^{k + 1} + (i ₂ is an arbitrary integer) The third element 4 _C is disposed at the position, and the fourth element 4 _C is shifted to the position by shifting the third element 4 _C by + (2i ₃ −1) π / 2 ^k (i ₃ is an arbitrary integer) in the x direction. _D may be arranged. By adopting the above arrangement, it is possible to substantially completely remove components other than the fundamental wave by making the value of n sufficiently large.

FIG. 14A is a diagram showing a configuration of the position detection apparatus 1 according to the fourth embodiment of the present invention. The position detection device 1 according to the present embodiment is different from the position detection device 1 according to the first embodiment in that the magnetic sensor 2 includes first to eighth elements 4 _A to 4 _H. . Hereinafter, the electrical connection form and physical arrangement of the first to eighth elements 4 _A to 4 _H will be described in detail.

FIG. 14B is a diagram showing an electrical connection form of the first to eighth elements 4 _A to 4 _H. As shown in the figure, in the present embodiment, the first to eighth elements 4 _A to 4 _H are each composed of two GMR elements. Specifically, the first to fourth elements 4 _A to 4 _D are the same as those in the first embodiment. The fifth element 4 _E includes two GMR elements 5 _E1 and 5 _E2 (two fifth detection elements), and the sixth element 4 _F includes two GMR elements 5 _F1 and 5 _F2 (2 And the seventh element 4 _G is composed of two GMR elements 5 _G1 and 5 _G2 (two seventh detection elements), and the eighth element 4 _H is It is constituted by two GMR elements 5 _H1 and 5 _H2 (two eighth detection elements).

Similarly to the first embodiment, the magnetic sensor 2 includes a power terminal 6 (first power terminal), a power terminal 7 (second power terminal), and output terminals 8a and 8b (first and second power terminals). In addition to having an output terminal), output terminals 8c and 8d (third and fourth output terminals) and subtractors 10 and 11 (first and second subtraction circuits) are further provided. The connections between the GMR elements 5 _A1 , 5 _A2 , 5 _B1 , 5 _B2 , 5 _C1 , 5 _C2 , 5 _D1 , 5 _D2 and the respective terminals are the same as in the first embodiment. On the other hand, the GMR elements 5 _E1 and 5 _E2 are connected in series between the output terminal 8 c and the power supply terminal 6 in this order. Similarly, the GMR elements 5 _F1 and 5 _F2 are connected in series between the power supply terminal 7 and the output terminal 8 c in this order, and the GMR elements 5 _G1 and 5 _G2 are connected in this order to the output terminal 8 d and the power supply terminal 6. The GMR elements 5 _H1 and 5 _H2 are connected in series between the power supply terminal 7 and the output terminal 8 d in this order. The output terminal 8a is connected to the non-inverting input terminal of the subtractor 10, the output terminal 8b is connected to the non-inverting input terminal of the subtractor 11, the output terminal 8c is connected to the inverting input terminal of the subtractor 10, and the output terminal 8d. Is connected to the inverting input terminal of the subtractor 11. The subtracter 10 outputs a voltage signal obtained by subtracting the voltage signal appearing at the output terminal 8c from the voltage signal appearing at the output terminal 8a, and this voltage signal becomes one output signal Vsin of the magnetic sensor 2. The subtractor 11 outputs a voltage signal obtained by subtracting the voltage signal appearing at the output terminal 8d from the voltage signal appearing at the output terminal 8b, and this voltage signal becomes the other output signal Vcos of the magnetic sensor 2.

In short, the above connection form is a full bridge connection similar to the connection form shown in FIG. In the present embodiment, the arrangement of GMR elements for using a second harmonic as a fundamental wave in the case of performing full-bridge connection will be described as in the first embodiment.

As in the case of the half bridge, the physical arrangement of each GMR element is such that when the output signals Vsin and Vcos are calculated, odd-order harmonics including the first-order component of φ are removed, and second-order harmonics (φ Of the second-order term) is determined to be a fundamental wave. Specifically, first, the arrangement of the first to fourth elements 4 _A to 4 _D may be the same as the arrangement described in the first embodiment (the arrangement shown in FIGS. 2 and 3). That is, two GMR elements (GMR elements 5 _A1 and 5 _A2 ) constituting the first element 4 _A are provided at two positions that are ± π / 2 apart from the first reference position B _{1 in the} x direction. Just place them one by one. In addition, the two GMR elements (GMR elements 5 _B1 and 5 _B2 ) constituting the second element 4 _B are connected to the second reference position B ₂ (= B ₁ + (2i ₁ −1) π / 2) x One piece may be arranged at two positions separated by ± π / 2 in the direction. The GMR elements 5 _C1 and 5 _C2 constituting the third element 4 _C may be arranged at positions where the GMR elements 5 _A1 and 5 _A2 are shifted by + (2i ₂ −1) π / 4 in the x direction. The GMR elements 5 _D1 and 5 _D2 constituting the fourth element 4 _D may be arranged at positions where the GMR elements 5 _B1 and 5 _B2 are shifted by + (2i ₃ −1) π / 2 in the x direction. However, i ₁ , i ₂ , and i ₃ are all numbers selected from arbitrary integers.

In the following description, the intermediate position between the GMR element 5 _C1 and the GMR element 5 _C2 is referred to as “third reference position B ₃ ”. According to this, the third reference position B ₃ is equal to B ₁ + (2i ₂ −1) π / 4. Two GMR elements (GMR elements 5 _C1 and 5 _C2 ) constituting the third element 4 _C are arranged at two positions that are ± π / 2 apart from the third reference position B _{3 in the} x direction. It will be arranged one by one. An intermediate position between the GMR element 5 _D1 and the GMR element 5 _D2 is referred to as a “fourth reference position B ₄ ”. According to this, the fourth reference position B ₄ becomes equal to B ₁ + (2i ₁ −1) π / 2 + (2i ₃ −1) π / 2. Then, two GMR elements (GMR elements 5 _D1 and 5 _D2 ) constituting the fourth element 4 _D are arranged at two positions that are ± π / 2 apart from the fourth reference position B _{4 in the} x direction. It will be arranged one by one.

The fifth to eighth elements 4 _E to 4 _H may be arranged at positions shifted by a predetermined distance in the x direction from the first to fourth elements 4 _A to 4 _D , respectively. Specifically, if a position that is separated from the first reference position B ₁ by + (2i ₄ −1) π / 2 in the x direction is a fifth reference position B ₅ , the second element 4 _E is formed. Two GMR elements (GMR elements 5 _E1 and 5 _E2 ) may be arranged one by one at two positions that are ± π / 2 apart from the fifth reference position B _{5 in the} x direction. Further, when the first reference position _{B 1} position in the x-direction + 2i ₅ [pi / 2 away from the reference position _{B 6} of the sixth, two GMR elements (GMR element _{5 F1} constituting the element _{4 F} sixth , 5 _F2 ) may be arranged one by one at two positions spaced ± π / 2 in the x direction from the sixth reference position B ₆ . Similarly, when the first reference from the position _{B 1} in the x-direction _{+ (2i 6 -1) π /} 2 + (2i 2 -1) π / 4 distant position seventh reference position _{B 7,} the seventh If two GMR elements (GMR elements 5 _G1 and 5 _G2 ) constituting the element 4 _G are arranged one by one at two positions that are ± π / 2 apart from the seventh reference position B _{7 in the} x direction. Good. Further, an eighth element 4 _H is configured by _assuming that a position away from the first reference position B ₁ by + 2i ₇ π / 2 + (2i ₂ −1) π / 4 in the x direction is an eighth reference position B _8. Two GMR elements (GMR elements 5 _H1 and 5 _H2 ) may be arranged one by one at two positions that are ± π / 2 apart from the eighth reference position B _{8 in the} x direction. However, i ₄ to i ₇ are all numbers selected from arbitrary integers.

Table 2 summarizes the arrangement of the _first to eighth reference positions B ₁ to B ₈ starting from the first reference position B ₁ . The two GMR elements constituting each of the first to eighth elements 4 _A to 4 _H are placed at two positions ± π / 2 away from the corresponding ones of the reference positions shown in the table in the x direction. By arranging them one by one, it becomes possible to use the second harmonic as the fundamental wave.

According to the position detection device 1 according to the present embodiment, the second harmonic can be used as a fundamental wave. Further, since the full bridge connection is used, it is possible to obtain an output twice that of the case of the herb bridge connection, and furthermore, it is possible to remove the DC component from the output signals Vsin and Vcos.

In the fourth embodiment, an example in which the second harmonic is a fundamental wave has been described. However, as in the case of the half-bridge connection described above, a higher-order harmonic is also obtained in a full-bridge connection. A wave can be a fundamental wave. Table 3, in the case of the 2 ^k harmonic and fundamental wave, summarizes the arrangement of the reference position B _{1 ~} B ₈ of the first to eighth.

If 1 is substituted for k in Table 3, the same arrangement as shown in Table 2 is obtained. As described above, the arrangement of the two GMR elements constituting each of the first to eighth elements 4 _A to 4 _H is set to one at two positions that are ± π / 2 apart from the corresponding reference position. That's fine.

FIG. 15A is a diagram showing a specific arrangement example of the GMR elements when k = 1 and each of the first to eighth elements 4 _A to 4 _H is constituted by two GMR elements. is there. In the same figure, the vertically long rectangles indicate individual GMR elements. In the example of the figure, i ₁ = 3, i ₂ = 2, i ₃ = 3, i ₄ = 1, i ₅ = 3, i ₆ = 1, and i ₇ = 3. By setting the values of i ₁ to i ₇ in this way, the GMR elements can be arranged at different positions on the x-axis as shown in FIG.

When k ≧ 2, 2 ⁿ GMR elements constituting each of the first to eighth elements 4 _A to 4 _H are moved ± π / Y ₁ ± π / Y ₂ ± π from the corresponding reference position. / _Y 3 in ··· ± π / _{Y n} distant ^{2 n} pieces of position may be arranged one by one. The specific values of the variables Y ₁ , Y ₂ ,... Use the second harmonic as the fundamental wave as in the case of n = 4 shown in FIG. When it is desired to remove the 16th order waves, Y ₁ = 2 and Y ₂ = 8, Y ₃ = 16, and Y ₄ = 32 may be set. For example, as in the case of n = 4 shown in FIG. 13, the second harmonic is used as the fundamental wave, and when it is desired to remove the first, fourth, sixth, and eighth waves, Y ₁ = 2; Y ₂ = 8; Y ₃ = 12; Y ₄ = 16.

FIG. 15 (b), k = 2, and shows a specific arrangement example of the GMR element when the elements ₄ A ~ _{4 H} respective first to eighth constituted by ^{two two} GMR elements It is. Also in this figure, the vertically long rectangles indicate individual GMR elements. The example in the figure is an example in the case where the fourth harmonic is used as a fundamental wave (Y ₁ = 2 and Y ₂ = 4), i ₁ = 5, i ₂ = 2, i ₃ = 5, i ₄ = 1, i ₅ = 5, i ₆ = 1, i ₇ = 5. By setting the values of i ₁ to i ₇ in this way, the GMR elements can be arranged at different positions on the x-axis as shown in FIG.

As described above, the arrangement of the GMR element in the case of adopting the full bridge connection has been described. Of course, it is also possible to adopt an arrangement other than the above arrangement. As a specific example, an arrangement similar to the example shown in FIG. In this case, the first element _{4 A} arranged GMR element as shown in FIG. 12, further for the second to eighth element ₄ B ~ _{4 H,} a first reference position B shown in FIG. 12 _After replacing ₁ with the reference positions B ₂ to B ₈ shown in Table 3, the GMR elements may be similarly arranged. This also makes it possible to use a 2 ^k- order harmonic as the fundamental wave.

Note that the harmonics other than the 2 ^k order cannot be the fundamental wave, and the full bridge connection is the same as the half bridge connection. Therefore, it is sufficient to determine the arrangement of the GMR element for using the 2 ^kth order (k ≧ 1) harmonic as the fundamental wave so that the 2 ^m order component (m is a positive integer smaller than k) is removed. . In addition, the arrangement of GMR elements for appropriately removing higher-order harmonics than the fundamental wave may be the same as in the case of half-bridge connection. In other words, when the harmonic used as the fundamental wave is the 2 ^k order, if the GMR element is arranged so that the 2 ^k +2 ^{k + 1} · Nth order component is removed, higher harmonics than the fundamental wave are also appropriately removed. It becomes possible.

In the case of performing the full bridge connection, the arrangement for removing the components other than the fundamental wave substantially completely is the same as in the case of the half bridge connection described above. That is, each of the first to eighth elements 4 _A to 4 _H is configured by 2 ⁿ GMR elements, and a 2 ^k- order component (k is a number selected from an arbitrary natural number) as a fundamental wave. In the case of leaving, first, for the first element 4 _A , a power-of-two order component other than the 2 ^k order component (2 ⁰ , 2 ¹ ,..., 2 ^k−1 , 2 ^{k + 1} , 2 ^{k + 2} ,. And 2 ^k P (P is a prime number greater than or equal to 3) (2 ^k · 3, 2 ^k · 5, 2 ^k · 7, 2 ^k · 11,...) An arrangement corresponding to the selected order may be adopted by selecting the number. The selection criteria may be the same as in the half-bridge connection. The second to eighth elements 4 _B to 4 _H can be arranged in the same manner as the first element 4 _A by using the reference positions shown in Table 3 instead of the _first reference position B _1. Good. By adopting the above arrangement, it is possible to substantially completely remove components other than the fundamental wave by making the value of n sufficiently large.

As mentioned above, although preferable embodiment of this invention was described, this invention is not limited to such embodiment at all, and this invention can be implemented in various aspects in the range which does not deviate from the summary. Of course.

For example, as described above, according to the present invention, the 2 ^k +2 ^{k + 1} Nth order component is also removed by removing the 2 ^k order component, but the arrangement for removing these automatically removed components is arranged. That doesn't mean you can't. For example, in the example shown in FIG. 12, since the second-order term component is removed, the sixth-order term component is automatically removed. However, as shown in FIG. I do not care.

Further, for example, in the example of FIGS. 15A and 15B, the detection elements are arranged at different positions on the x-axis, but this is not always necessary. For example, by arranging the detection elements side by side in the normal direction of the surface 3a, it is possible to obtain the same output as when the detection elements are arranged at different positions on the x-axis without impairing the phase relationship. Become.

In each of the above-described embodiments, the example in which the GMR element is used as the detection element has been described. However, the present invention is also applicable to the case where another type of magnetoresistive element such as an AMR element or a TMR (tunnel-magnetoresistive) element is used as the detection element. it can. When an AMR element is used, it is possible to obtain a higher resolution than that of a conventional position detection apparatus that similarly uses an AMR element.

The present invention can also be applied to the optical position detection device described above. In this case, an optical scale having a diffraction pattern formed on the surface is used instead of the magnetic scale 3. Further, an optical sensor is used instead of the magnetic sensor 2, and the detection element is a photodetection element. When the optical sensor is moved along the surface of the optical scale, the amount of received light is the same signal as the GMR readout signal shown in equations (20) to (23). According to the present invention, even-order harmonics can be used as the fundamental wave in this signal. Therefore, even in an optical position detection device, it is possible to obtain a resolution that is at least twice that of the prior art.

In each of the above embodiments, the GMR element electrical connection order and the physical arrangement order are associated with each other with priority given to ease of explanation, but these do not need to be associated with each other. It is. For example, FIG. 17 shows a modified example of the arrangement of the GMR elements shown in FIGS. In the example shown in FIG. 2, the physical arrangement order of the GMR elements is different from the example shown in FIGS. 2A and 2B, but the second harmonic is used as the fundamental wave. (A) The same effect as the example shown in (b) can be obtained. The specific arrangement order may be determined in consideration of the ease of wiring.

In addition to the linear scale (magnetic linear scale, optical linear scale) as shown in FIG. 1 (a), the present invention provides an annular or curved scale (magnetic rotary encoder, optical rotary encoder). The same applies when used. That is, it can be applied to all measuring instruments having periodicity with respect to a certain physical property value.

FIGS. 18, 19, 20, and 21 show examples in which the same arrangement of GMR elements as in FIGS. 9, 12, 13, and 16 is applied to an annular encoder. FIG. 22 shows an example in which the same arrangement of GMR elements as in FIGS. 15A and 15B is applied to an annular encoder. As shown in these drawings, the present invention is also applicable to an annular encoder.

1 position detecting device 2 magnetic sensor 3 magnetic scale _{4 A-4 H} first to eighth element _{5 A1 -5 A4, 5 B1 -5} B4, 5 C1 -5 C4, 5 D1 -5 D4, 5 E1 -5 _E4 , 5 _F1 -5 _F4 , 5 _G1 -5 _G4 , 5 _H1 -5 _H4 GMR element 6 First power supply terminal 7 Second power supply terminals 8a to 8d First to fourth output terminals 9 Position acquisition unit B ₁ B ₈ 1st to 8th reference positions P ₁ to P ₁₂ 1st to 12th positions

Claims (26)

1. A scale having a first surface extending along a moving direction of the object to be detected;
   A sensor configured to be movable with the object and disposed opposite the first surface;
   Position acquisition means for acquiring the position of the position detection target object based on an output signal of the sensor;
   The sensor is
   A first power supply terminal to which a first power supply potential is supplied;
   A second power supply terminal to which a second power supply potential different from the first power supply potential is supplied;
   First and second output terminals;
   A first element connected between the first output terminal and the first power supply terminal;
   A second element connected between the second power supply terminal and the first output terminal;
   A third element connected between the second output terminal and the first power supply terminal;
   A fourth element connected between the second power supply terminal and the second output terminal;
   The first element comprises a plurality of first detection elements connected in series between the first output terminal and the first power supply terminal and juxtaposed along the moving direction,
   The third element includes a plurality of third detection elements connected in series between the second output terminal and the first power supply terminal and juxtaposed along the moving direction.
   Each of the first detection elements and each of the third detection elements generates a predetermined readout signal corresponding to the facing position of the scale when moving in the movement direction along the first surface. Configured,
   The arrangement of the plurality of first detection elements in the moving direction is determined so that at least a first-order component of a phase is removed from a voltage signal appearing at the first output terminal,
   The arrangement of the plurality of third detection elements in the moving direction is determined so that at least a first-order component of a phase is removed from a voltage signal appearing at the second output terminal,
   The position acquisition means calculates the position of the object to be detected based on a voltage signal appearing at the first output terminal and a voltage signal appearing at the second output terminal. apparatus.
2. The second element includes a plurality of second detection elements connected in series between the second power supply terminal and the first output terminal and juxtaposed along the moving direction.
   The fourth element includes a plurality of fourth detection elements connected in series between the second power supply terminal and the second output terminal and juxtaposed along the moving direction.
   The arrangement of the plurality of second detection elements in the moving direction is determined so that at least a first-order component of a phase is removed from a voltage signal appearing at the first output terminal,
   The arrangement of the plurality of fourth detection elements in the moving direction is determined so that at least a first-order component of a phase is removed from a voltage signal appearing at the second output terminal. The position detection apparatus described in 1.
3. The first element is composed of 2 ⁿ first detection elements (n is a number selected from an arbitrary natural number),
   The third element is composed of 2 ⁿ third detection elements,
   The 2 ⁿ first detection elements are:
   When n = 1, one is disposed at each of the first and second positions separated by ± π / 2 in the moving direction from the first reference position,
   If n ≧ 2, the second position is one at each of 2 ⁿ⁻¹ positions separated by ± π / 8... ± π / 2 ^{n + 1 in the} moving direction from the first position. ^{One at} each of 2 ⁿ⁻¹ positions separated from each other by ± π / 8... ± π / 2 ^{n + 1 in the} moving direction.
   3. The 2 ⁿ third detection elements are arranged at positions shifted from the 2 ⁿ first detection elements by a first predetermined distance in the movement direction, respectively. Position detector.
4. The second element is composed of 2 ⁿ second detection elements,
   The fourth element includes 2 ⁿ fourth detection elements,
   The 2 ⁿ second detection elements are:
   When n = 1, ± 1/2 in the movement direction from the first reference position (where l is a number selected from an arbitrary odd number) is further ±± in the movement direction, respectively. arranged at third and fourth positions separated by π / 2,
   When n ≧ 2, one in each of the 2 ⁿ⁻¹ positions that are separated from each other by ± π / 8... ± π / 2 ^{n + 1 in the} moving direction from the third position. ^{One at} each of 2 ⁿ⁻¹ positions separated from each other by ± π / 8... ± π / 2 ^{n + 1 in the} moving direction.
   The ²ⁿ fourth detection elements are arranged at positions shifted from the ²ⁿ second detection elements by a second predetermined distance in the moving direction. Position detector.
5. The first element is composed of 2 ⁿ first detection elements (n is a number selected from an arbitrary natural number),
   The third element is composed of 2 ⁿ third detection elements,
   The arrangement of the 2 ⁿ first detection elements in the movement direction is a power-of-two order component other than a 2 ^k order component (k is a number selected from an arbitrary natural number) and a 2 ^k P order component. (P is a prime number greater than or equal to 3) and n components selected from among them are determined to be removed,
   3. The 2 ⁿ third detection elements are arranged at positions shifted from the 2 ⁿ first detection elements by a first predetermined distance in the movement direction, respectively. Position detector.
6. The second element is composed of 2 ⁿ second detection elements,
   The fourth element includes 2 ⁿ fourth detection elements,
   The 2 ⁿ second detection elements are arranged at positions shifted from the 2 ⁿ first detection elements by a third predetermined distance in the movement direction, respectively.
   The said ²ⁿ 4th detection element is arrange | positioned in the position which shifted each said ²ⁿ 2nd detection element by the 2nd predetermined distance to the said movement direction. Position detector.
7. The first element includes 2 ⁿ (n is a number selected from any two or more natural numbers) of the first detection elements,
   The third element is composed of 2 ⁿ third detection elements,
   The 2 ⁿ first detection elements are:
   When n = 2, 1 is set to 5th and 6th positions that are further separated by ± π / 4 in the movement direction from the first position that is + π / 2 away from the first reference position in the movement direction. One by one from the second position, which is -π / 2 away from the first reference position in the movement direction, to the seventh and eighth positions, which are further separated by ± π / 4 in the movement direction, respectively. Arranged,
   When n ≧ 3, each of the sixth positions is one in 2 ⁿ⁻² positions that are separated by ± π / 16... ± π / 2 ^{n + 1 in the} moving direction from the fifth position. one by one from the position in each of ± π / 16 ··· ± π / 2 n + 1 apart 2 ^n-2 pieces of position in the moving direction, the seventh, respectively ± π / 16 ·· from the position in the moving direction of the one by one · ± a [pi ^{/ 2 n + 1} apart ^{2 n-2} pieces of position, ^{2 n-2} pieces that each ^{± π / 16 ··· ± π /} 2 n + 1 apart in the moving direction from the position of the eighth One at each position,
   3. The 2 ⁿ third detection elements are arranged at positions shifted from the 2 ⁿ first detection elements by a first predetermined distance in the movement direction, respectively. Position detector.
8. The second element is composed of 2 ⁿ second detection elements,
   The fourth element includes 2 ⁿ fourth detection elements,
   The 2 ⁿ second detection elements are:
   When n = 2, + π // 4 further in the movement direction from a second reference position that is πl / 4 away from the first reference position in the movement direction (l is a number selected from an arbitrary odd number). A third position separated from the second reference position by −π / 2 from the second reference position, one at each of the ninth and tenth positions separated by ± π / 4 in the movement direction from the third position separated by two. One at each of the eleventh and twelfth positions, which are further separated from each other by ± π / 4 in the moving direction from the position of 4, respectively.
   If n ≧ 3, the tenth position is one at each of 2 ⁿ⁻² positions that are ± π / 16... ± π / 2 ^{n + 1} apart from the ninth position in the moving direction. one by one from the position in each of ± π / 16 ··· ± π / 2 n + 1 apart 2 ^n-2 pieces of position in the moving direction, the second 11, respectively ± π / 16 ·· from the position in the moving direction of the one by one · ± a [pi ^{/ 2 n + 1} apart ^{2 n-2} pieces of position, ^{2 n-2} pieces that each ^{± π / 16 ··· ± π /} 2 n + 1 apart in the moving direction from the position of the first 12 One at each position,
   The 2 ⁿ fourth detection elements are arranged at positions shifted from the 2 ⁿ second detection elements by a second predetermined distance in the movement direction, respectively. Position detector.
9. The scale is a magnetic scale magnetized so that N poles and S poles appear alternately along the moving direction on the first surface,
   The position detection device according to any one of claims 1 to 8, wherein the detection element is a magnetoresistive element.
10. The scale is a magnetic scale magnetized so that N poles and S poles appear alternately along the moving direction on the first surface,
    The detection element is a magnetoresistive element;
    The position detection apparatus according to claim 1, wherein each of the second and fourth elements includes a resistance element configured not to be affected by a magnetic field formed by the magnetic scale.
11. The position detection device according to claim 9 or 10, wherein the magnetoresistive element is any one of a GMR element, an AMR element, and a TMR element.
12. The scale is an optical scale having a diffraction pattern formed on the first surface;
    The position detection device according to any one of claims 1 to 8, wherein the detection element is a light detection element.
13. The position detection apparatus according to claim 1, wherein each of the second and fourth elements includes a constant current source.
14. The position detection apparatus according to any one of claims 1 to 13, wherein the first power supply potential is a ground potential.
15. A scale having a first surface extending along a moving direction of the object to be detected;
    A sensor configured to be movable with the object and disposed opposite the first surface;
    Position acquisition means for acquiring the position of the position detection target object based on an output signal of the sensor;
    The sensor is
    A first power supply terminal to which a first power supply potential is supplied;
    A second power supply terminal to which a second power supply potential different from the first power supply potential is supplied;
    First and second output terminals;
    A first element connected between the first output terminal and the first power supply terminal;
    A second element connected between the second power supply terminal and the first output terminal;
    A third element connected between the second output terminal and the first power supply terminal;
    A fourth element connected between the second power supply terminal and the second output terminal;
    The first element comprises a plurality of first detection elements connected in series between the first output terminal and the first power supply terminal and juxtaposed along the moving direction,
    The third element includes a plurality of third detection elements connected in series between the second output terminal and the first power supply terminal and juxtaposed along the moving direction.
    Each of the first detection elements and each of the third detection elements generates a predetermined readout signal corresponding to the facing position of the scale when moving in the movement direction along the first surface. Configured,
    The arrangement of the plurality of first detection elements in the moving direction is such that a voltage signal appearing at the first output terminal includes at least a 2 ^k- order component and a 2 ^k +2 ^{k + 1} · N-order component (k is an arbitrary natural number). A number selected from the above, N is a positive integer), and at least the 2 ^m order component of the phase and the 2 ^m +2 ^{m + 1} · N order term component (m is smaller than k) from the voltage signal appearing at the first output terminal Positive integer) is removed,
    The arrangement of the plurality of third detection elements in the movement direction is such that at least a 2 ^k order component and a 2 ^k +2 ^{k + 1} · N order component of the phase remain in the voltage signal appearing at the second output terminal. Is determined so that at least the 2 ^m order component and the 2 ^m +2 ^{m + 1} · N order component of the phase are removed from the voltage signal appearing at the output terminal of
    The position acquisition means calculates the position of the object to be detected based on a voltage signal appearing at the first output terminal and a voltage signal appearing at the second output terminal. apparatus.
16. The arrangement of the plurality of first detection elements in the moving direction is determined so that the 2 ^k +2 ^{k + 1} · N-order component of the phase is also removed from the voltage signal appearing at the first output terminal,
    The arrangement of the plurality of third detection elements in the moving direction is determined so that a 2 ^k +2 ^{k + 1} · N-th order component of a phase is also removed from a voltage signal appearing at the second output terminal. The position detection device according to claim 15.
17. A scale having a first surface extending along a moving direction of the object to be detected;
    A sensor configured to be movable with the object and disposed opposite the first surface;
    Position acquisition means for acquiring the position of the position detection target object based on an output signal of the sensor;
    The sensor is
    A first power supply terminal to which a first power supply potential is supplied;
    A second power supply terminal to which a second power supply potential different from the first power supply potential is supplied;
    First to fourth output terminals;
    A first element connected between the first output terminal and the first power supply terminal;
    A second element connected between the second power supply terminal and the first output terminal;
    A third element connected between the second output terminal and the first power supply terminal;
    A fourth element connected between the second power supply terminal and the second output terminal;
    A fifth element connected between the third output terminal and the first power supply terminal;
    A sixth element connected between the second power supply terminal and the third output terminal;
    A seventh element connected between the fourth output terminal and the first power supply terminal;
    An eighth element connected between the second power supply terminal and the fourth output terminal;
    A first subtraction circuit that outputs a voltage signal obtained by subtracting a voltage signal appearing at the third output terminal from a voltage signal appearing at the first output terminal;
    A second subtracting circuit that outputs a voltage signal obtained by subtracting a voltage signal appearing at the fourth output terminal from a voltage signal appearing at the second output terminal;
    The first element comprises a plurality of first detection elements connected in series between the first output terminal and the first power supply terminal and juxtaposed along the moving direction,
    The third element includes a plurality of third detection elements connected in series between the second output terminal and the first power supply terminal and juxtaposed along the moving direction.
    The fifth element includes a plurality of fifth detection elements connected in series between the third output terminal and the first power supply terminal and juxtaposed along the moving direction,
    The seventh element includes a plurality of seventh detection elements connected in series between the fourth output terminal and the first power supply terminal and juxtaposed along the moving direction,
    Each of the first detection elements, the third detection elements, the fifth detection elements, and the seventh detection elements move in the movement direction along the first surface. , Configured to generate a predetermined readout signal according to the opposing position of the scale,
    The arrangement of the plurality of first detection elements in the movement direction and the arrangement of the plurality of fifth detection elements in the movement direction are such that at least a first-order component of the phase from the output signal of the first subtraction circuit Decided to be removed,
    The arrangement of the plurality of third detection elements in the movement direction and the arrangement of the plurality of seventh detection elements in the movement direction are such that at least a first-order component of the phase from the output signal of the second subtraction circuit Decided to be removed,
    The position acquisition device calculates the position of the object to be detected based on an output signal of the first subtraction circuit and an output signal of the second subtraction circuit.
18. The second element includes a plurality of second detection elements connected in series between the second power supply terminal and the first output terminal and juxtaposed along the moving direction.
    The fourth element includes a plurality of fourth detection elements connected in series between the second power supply terminal and the second output terminal and juxtaposed along the moving direction.
    The sixth element includes a plurality of sixth detection elements connected in series between the second power supply terminal and the third output terminal, and juxtaposed along the movement direction,
    The eighth element includes a plurality of eighth detection elements connected in series between the second power supply terminal and the fourth output terminal and juxtaposed along the movement direction,
    The arrangement of the plurality of second detection elements in the movement direction and the arrangement of the plurality of sixth detection elements in the movement direction are such that at least the first-order component of the phase from the output signal of the first subtraction circuit. Decided to be removed,
    The arrangement of the plurality of fourth detection elements in the movement direction and the arrangement of the plurality of eighth detection elements in the movement direction are such that at least the first-order component of the phase is derived from the output signal of the second subtraction circuit. The position detection device according to claim 17, wherein the position detection device is determined to be removed.
19. The first element is composed of 2 ⁿ first detection elements (n is a number selected from an arbitrary natural number),
    The third element is composed of 2 ⁿ third detection elements,
    The fifth element includes 2 ⁿ of the fifth detection elements,
    The seventh element is composed of 2 ⁿ seventh detection elements,
    The 2 ⁿ first detection elements are arranged one by one at 2 ⁿ positions separated from each other by ± π / 2 ± π / 8... ± π / 2 ^{n + 1 in the} movement direction from the first reference position. Arranged,
    The 2 ⁿ third detection elements are spaced apart from the first reference position in the movement direction by (2i ₂ −1) π / 4 (where i ₂ is a number selected from an arbitrary integer). One at each of 2 ⁿ positions apart from each other by ± π / 2 ± π / 8... ± π / 2 ^{n + 1 in the} moving direction from the three reference positions;
    The 2 ⁿ fifth detection elements are spaced apart from the first reference position in the movement direction by (2i ₄ −1) π / 2 (i ₄ is a number selected from an arbitrary integer). 1 is arranged at 2 ⁿ positions apart from each other by ± π / 2 ± π / 8... ± π / 2 ^{n + 1 in the} moving direction from 5 reference positions,
    The 2 ⁿ seventh detection elements are (2i ₆ −1) π / 2 + (2i ₂ −1) π / 4 (i ₆ is an arbitrary integer in the moving direction from the first reference position. be arranged from the seventh reference position apart a few) selected one for each ± π / 2 ± π / 8 ··· ± π / 2 n + 1 apart the 2 ⁿ position in the moving direction from The position detection device according to claim 18.
20. The second element is composed of 2 ⁿ second detection elements,
    The fourth element includes 2 ⁿ fourth detection elements,
    The sixth element is composed of 2 ⁿ sixth detection elements,
    The eighth element includes 2 ⁿ of the eighth detection elements,
    The 2 ⁿ second detection elements are spaced apart from the first reference position in the movement direction by (2i ₁ −1) π / 2 (where i ₁ is a number selected from an arbitrary integer). One at each of 2 ⁿ positions separated from each other by ± π / 2 ± π / 8... ± π / 2 ^{n + 1 in the} moving direction from the two reference positions,
    The 2 ⁿ fourth detection elements are (2i ₃ −1) π / 2 + (2i ₂ −1) π / 4 (i ₃ is an arbitrary integer in the moving direction from the first reference position. is arranged from the fourth reference position apart a few) selected one for each ± π / 2 ± π / 8 ··· ± π / 2 n + 1 apart the 2 ⁿ position in the moving direction from,
    The 2 ⁿ sixth detection elements are arranged at a sixth reference position that is 2i ₅ π / 2 away from the first reference position in the movement direction (i ₅ is a number selected from an arbitrary integer). Are arranged one by one at 2 ⁿ positions apart from each other by ± π / 2 ± π / 8... ± π / 2 ^{n + 1 in the} moving direction.
    The 2 ⁿ eighth detection elements are selected from 2i ₇ π / 2 + (2i ₂ −1) π / 4 (i ₇ is an arbitrary integer) in the movement direction from the first reference position. characterized in that it is arranged number) from a distant eighth reference position, one for each ± π / 2 ± π / 8 ··· ± π / 2 n + 1 apart the 2 ⁿ position in the moving direction The position detection device according to claim 19.
21. The first element is composed of 2 ⁿ first detection elements (n is a number selected from an arbitrary natural number),
    The third element is composed of 2 ⁿ third detection elements,
    The fifth element includes 2 ⁿ of the fifth detection elements,
    The seventh element is composed of 2 ⁿ seventh detection elements,
    The arrangement of the 2 ⁿ first detection elements in the movement direction is a power-of-two order component other than a 2 ^k order component (k is a number selected from an arbitrary natural number) and a 2 ^k P order component. (P is a prime number greater than or equal to 3) and n components selected from among them are determined to be removed,
    The 2 ⁿ third detection elements are (2i ₂ −1) π / 2 ^{k + 1} (i ₂ is selected from arbitrary integers) in the movement direction with respect to each of the 2 ⁿ first detection elements. Are arranged at a shifted position,
    The 2 ⁿ fifth detection elements are each selected from (2i ₄ −1) π / 2 ^k (i ₄ is an arbitrary integer) in the moving direction with respect to each of the 2 ⁿ first detection elements. Are arranged at a shifted position,
    Detecting element of the ^{2 n} pieces of seventh, the ^two respective ⁿ first detector element in the moving direction ^{_{(2i 6 -1) π / 2}} k + (2i 2 -1) π / 2 k + 1 ( The position detection device according to claim 18, wherein i ₆ is arranged at a position shifted by a number selected from an arbitrary integer.
22. The second element is composed of 2 ⁿ second detection elements,
    The fourth element includes 2 ⁿ fourth detection elements,
    The sixth element is composed of 2 ⁿ sixth detection elements,
    The eighth element includes 2 ⁿ of the eighth detection elements,
    The ^{2 n} pieces of the second detection element, wherein the ² each ^n-number of the first detection element in the moving direction ^{_{(2i 1 -1) π / 2}} k (i 1 is selected from any integer Are arranged at a shifted position,
    The ^{2 n} pieces of the fourth detection element, wherein the ² each ^n-number of the first detection element in the moving direction ^{_{(2i 3 -1) π / 2}} k + (2i 2 -1) π / 2 k + 1 ( i ₃ is arranged at a position shifted by a number selected from an arbitrary integer)
    The 2 ⁿ sixth detection elements shift the 2 ⁿ first detection elements by 2i ₅ π / 2 ^{k in the} moving direction (where i ₅ is a number selected from an arbitrary integer). Placed at
    The 2 ⁿ eighth detection elements are arranged so that each of the 2 ⁿ first detection elements is 2i ₇ π / 2 ^k + (2i ₂ −1) π / 2 ^{k + 1} (i ₇ is arbitrary) in the moving direction. The position detection device according to claim 21, wherein the position detection device is arranged at a shifted position.
23. The first element includes 2 ⁿ (n is a number selected from any two or more natural numbers) of the first detection elements,
    The third element is composed of 2 ⁿ third detection elements,
    The fifth element includes 2 ⁿ of the fifth detection elements,
    The seventh element is composed of 2 ⁿ seventh detection elements,
    The 2 ⁿ first detection elements are:
    When n = 2, 1 is set to 5th and 6th positions that are further separated by ± π / 4 in the movement direction from the first position that is + π / 2 away from the first reference position in the movement direction. One by one from the second position, which is -π / 2 away from the first reference position in the movement direction, to the seventh and eighth positions, which are further separated by ± π / 4 in the movement direction, respectively. Arranged,
    When n ≧ 3, each of the sixth positions is one in 2 ⁿ⁻² positions that are separated by ± π / 16... ± π / 2 ^{n + 1 in the} moving direction from the fifth position. one by one from the position in each of ± π / 16 ··· ± π / 2 n + 1 apart 2 ^n-2 pieces of position in the moving direction, the seventh, respectively ± π / 16 ·· from the position in the moving direction of the one by one · ± a [pi ^{/ 2 n + 1} apart ^{2 n-2} pieces of position, ^{2 n-2} pieces that each ^{± π / 16 ··· ± π /} 2 n + 1 apart in the moving direction from the position of the eighth One at each position,
    The 2 ⁿ third detection elements are each selected from (2i ₂ −1) π / 8 (i ₂ is an arbitrary integer) in the movement direction for each of the 2 ⁿ first detection elements. Number)
    The 2 ⁿ fifth detection elements are each selected from (2i ₄ −1) π / 4 (i ₄ is an arbitrary integer) in the moving direction for each of the 2 ⁿ first detection elements. Number)
    The 2 ⁿ seventh detection elements are arranged so that each of the 2 ⁿ first detection elements is (2i ₆ −1) π / 4 + (2i ₂ −1) π / 8 (i ₆ The position detection device according to claim 18, wherein the position detection device is arranged at a position shifted by a number selected from an arbitrary integer.
24. The second element is composed of 2 ⁿ second detection elements,
    The fourth element includes 2 ⁿ fourth detection elements,
    The sixth element is composed of 2 ⁿ sixth detection elements,
    The eighth element includes 2 ⁿ of the eighth detection elements,
    The 2 ⁿ second detection elements are each selected from (2i ₁ −1) π / 4 (i ₁ is an arbitrary integer) in the movement direction for each of the 2 ⁿ first detection elements. Number)
    The 2 ⁿ fourth detection elements move (2i ₃ −1) π / 4 + (2i ₂ −1) π / 8 (i ₃ in the moving direction) to each of the 2 ⁿ first detection elements. A number selected from an arbitrary integer)
    The 2 ⁿ sixth detection elements are shifted from the 2 ⁿ first detection elements by 2i ₅ π / 4 (i ₅ is a number selected from an arbitrary integer) in the movement direction. Placed in position,
    The 2 ⁿ eighth detection elements are arranged so that each of the 2 ⁿ first detection elements is 2i ₇ π / 4 + (2i ₂ −1) π / 8 (i ₇ is an arbitrary integer) in the moving direction. The position detection device according to claim 23, wherein the position detection device is arranged at a position shifted by a number selected from among the positions.
25. A scale having a first surface extending along a moving direction of the object to be detected;
    A sensor configured to be movable with the object and disposed opposite the first surface;
    Position acquisition means for acquiring the position of the position detection target object based on an output signal of the sensor;
    The sensor is
    A first power supply terminal to which a first power supply potential is supplied;
    A second power supply terminal to which a second power supply potential different from the first power supply potential is supplied;
    First to fourth output terminals;
    A first element connected between the first output terminal and the first power supply terminal;
    A second element connected between the second power supply terminal and the first output terminal;
    A third element connected between the second output terminal and the first power supply terminal;
    A fourth element connected between the second power supply terminal and the second output terminal;
    A fifth element connected between the third output terminal and the first power supply terminal;
    A sixth element connected between the second power supply terminal and the third output terminal;
    A seventh element connected between the fourth output terminal and the first power supply terminal;
    An eighth element connected between the second power supply terminal and the fourth output terminal; and a voltage signal appearing at the third output terminal is subtracted from a voltage signal appearing at the first output terminal. A first subtraction circuit that outputs a voltage signal
    A second subtracting circuit that outputs a voltage signal obtained by subtracting a voltage signal appearing at the fourth output terminal from a voltage signal appearing at the second output terminal;
    The first element comprises a plurality of first detection elements connected in series between the first output terminal and the first power supply terminal and juxtaposed along the moving direction,
    The third element includes a plurality of third detection elements connected in series between the second output terminal and the first power supply terminal and juxtaposed along the moving direction.
    The fifth element comprises a plurality of fifth detection elements connected in series between the third output terminal and the first power supply terminal and juxtaposed along the moving direction,
    The seventh element includes a plurality of seventh detection elements connected in series between the fourth output terminal and the first power supply terminal and juxtaposed along the moving direction,
    Each of the first detection elements, the third detection elements, the fifth detection elements, and the seventh detection elements move in the movement direction along the first surface. , Configured to generate a predetermined readout signal according to the opposing position of the scale,
    The arrangement of the plurality of first detection elements in the movement direction and the arrangement of the plurality of fifth detection elements in the movement direction are such that an output signal of the first subtraction circuit has at least a 2 ^k- order component of phase. And 2 ^k +2 ^{k + 1} · Nth-order term component (k is a number selected from an arbitrary natural number, N is a positive integer), and at least the 2 ^mth- order component of the phase from the voltage signal appearing at the first output terminal And 2 ^m +2 ^{m + 1} · Nth order component (m is a positive integer smaller than k) is determined to be removed,
    The arrangement of the plurality of third detection elements in the movement direction and the arrangement of the plurality of seventh detection elements in the movement direction are such that an output signal of the second subtraction circuit includes at least a 2 ^k- order component of phase. and the balance ^{2 k +2} k ^{+ 1} · N order term component, ^{2 m} order term component and ^{2 m +2} m ^{+ 1} · N order term component of at least a phase from the voltage signal appearing at the second output terminal is determined to be removed,
    The position acquisition device calculates the position of the object to be detected based on an output signal of the first subtraction circuit and an output signal of the second subtraction circuit.
26. The arrangement of the plurality of first detection elements in the movement direction and the arrangement of the plurality of fifth detection elements in the movement direction are determined from the output signal of the first subtraction circuit by a phase of 2 ^k +2 ^{k + 1} · The Nth order component is also determined to be removed,
    The arrangement of the plurality of third detection elements in the movement direction and the arrangement of the plurality of seventh detection elements in the movement direction are determined from the output signal of the second subtraction circuit by a phase of 2 ^k +2 ^{k + 1} · The position detection device according to claim 25, wherein the position detection device is determined so as to remove the N-th order component.

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