Position detection device, position detection system, position detection method, and position detection program

Abstract

To provide a position detection device that can accurately detect an absolute position.SOLUTION: There is provided a position detection device comprising: an acquisition unit that acquires, from a detection object device including a detection unit that has a plurality of magnetic sensor parts arranged at positions different from each other in a predetermined direction, and a moving unit that is movable in the predetermined direction relative to the detection unit and gives a magnetic field pattern according to the position with respect to the detection unit to the plurality of magnetic sensor parts, the magnetic field patterns measured by the plurality of magnetic sensor parts; a reference pattern output unit that outputs reference patterns corresponding to a plurality of candidate positions of the moving unit with respect to the detection unit; and a position detection unit that, based on a result of comparison between the acquired magnetic field patterns and the reference patterns corresponding to each of the plurality of candidate positions, detects if any one of the plurality of candidate positions is the position of the moving unit with respect to the detection unit.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a position detection device, a position detection system, a position detection method, and a position detection program. [Background technology]

[0002] Conventionally, relative position detection has been used to detect the position of an object that moves within a predetermined range of motion, such as the movement of a lens in an imaging device. Devices that use relative position detection first move the object to a reference position and then detect the position of the object by detecting the amount of movement from the reference position. For this reason, devices that use relative position detection require the object, such as a lens, to be moved to the reference position after startup before they can be used for actual purposes such as taking pictures, which means that it takes time from startup until they are ready for actual use.

[0003] In contrast, Patent Document 1 and Patent Document 2 disclose devices that perform absolute position detection. Patent Document 1 describes that "the position detection magnet 101 is arranged at a predetermined angle θ in the movement direction of the lens holder 102 with respect to a line parallel to the optical axis L (the movement direction of the lens holder 102)" (paragraph 0012), and that "the peak values ​​of the detection signals Asinθ and Acosθ output from the position detection element 100 are configured to decrease or increase as the optical lens 103 moves in the direction of the optical axis L" (paragraph 0016), and that this allows the position of the position detection magnet 101 in the optical axis direction to be calculated from the peak values ​​of the detection signals.

[0004] Patent Document 2 states that "the position detection unit has a potentiometer 20 as a first sensor, a position detection magnet 22 as a second sensor, and an MR element 24 (magnetic resistance element) arranged to face the potentiometer 20" (paragraph 0026), and that "in the position detection unit of this embodiment, it is possible to identify in which cycle of the sinusoidal signal the position to be detected is located, based on the output value of the potentiometer 20 and the voltage values ​​(P0, P1...PN) pre-stored in the memory 26. Therefore, after the initial adjustment before shipping from the factory, it is possible to directly and accurately detect the absolute position of the zoom adjustment lens 16 at startup, without having to move the zoom adjustment lens 16 to the wide end or telephoto end" (paragraph 0047). [Prior art document] [Patent documents] [Patent Document 1] JP 2009-169202 A [Patent Document 2] JP 2013-36795 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the devices described in Patent Documents 1 and 2, the structure becomes complicated because the position detection magnet 101 is arranged at an angle θ with respect to the direction of movement, and a potentiometer is provided in addition to the magnetic sensor. [Means for solving the problem]

[0006] A first aspect of the present invention provides a position detection device. The position detection device may include a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction. The position detection device may include an acquisition unit that acquires a magnetic field pattern measured by the plurality of magnetic sensor units from a detection target device including a mobile unit that is movable in a predetermined direction relative to the detection unit and provides the plurality of magnetic sensor units with a magnetic field pattern according to its position relative to the detection unit. The position detection device may include a reference pattern output unit that outputs a reference pattern corresponding to each of a plurality of candidate positions of the mobile unit relative to the detection unit. The position detection device may include a detection unit that detects which of the plurality of candidate positions is the position of the mobile unit relative to the detection unit based on a result of comparing the acquired magnetic field pattern with the reference patterns corresponding to each of the plurality of candidate positions.

[0007] Each of the plurality of magnetic sensor units may include two or more magnetic sensors. Each of the plurality of magnetic sensor units may include a calculation unit that calculates a detection value corresponding to the magnetic sensor unit in the magnetic field pattern based on output values ​​of the two or more magnetic sensors.

[0008] The calculation unit may calculate, as the detection value, a difference between output values ​​of the magnetic sensors included in the two or more magnetic sensors.

[0009] The interval between the two or more magnetic sensors in each of the plurality of magnetic sensor units may be smaller than the interval between adjacent magnetic sensor units in the plurality of magnetic sensor units.

[0010] The detection unit may determine, from among the reference patterns corresponding to the plurality of candidate positions, the candidate position associated with the reference pattern that is closest to the magnetic field pattern, as the position of the mobile unit relative to the detection unit.

[0011] The detection unit may determine, from among the reference patterns corresponding to each of the multiple candidate positions, the candidate position associated with a reference pattern whose difference from the magnetic field pattern is less than a predetermined reference difference as the position of the mobile unit relative to the detection unit.

[0012] The position detection device may include a range determination unit that determines a detection range for the position of the mobile unit relative to the detection unit to be a part of the movable range based on the magnetic field patterns measured by the multiple magnetic sensor units. The detection unit may detect a position within the detection range for the mobile unit relative to the detection unit based on a result of comparing the magnetic field pattern with a reference pattern corresponding to a position within the detection range.

[0013] The range specifying unit may specify the detection target range based on the magnitude relationship between the detection values ​​included in the magnetic field pattern.

[0014] When the detection unit detects that the position of the mobile unit relative to the detection unit is a position corresponding to the reference pattern, the detection unit may determine the final position of the mobile unit relative to the detection unit using the detection value of the magnetic sensor unit corresponding to that position.

[0015] The detection section may be capable of switching between outputting the position associated with the reference pattern or the final position as the position of the mobile unit relative to the detection unit.

[0016] After detecting that the position of the mobile unit relative to the detection unit is the target position, the detection unit may detect whether the mobile unit has moved away from the target position based on the results of comparing the magnetic field pattern with a reference pattern associated with the target position.

[0017] The position detection device may include a reference data storage unit that stores reference data including a plurality of pairs of positions of the mobile unit relative to the detection unit and reference patterns corresponding to the positions.

[0018] The reference pattern output unit may smooth a predetermined number of reference patterns in the reference data, the corresponding positions of which are adjacent to each other, and output the smoothed reference patterns as reference patterns used to detect the position of the mobile unit relative to the detection unit.

[0019] In the reference data creation process, the acquisition unit may acquire a magnetic field pattern at each position of the mobile unit relative to the detection unit as a reference pattern, and for each position, the acquisition unit may smooth a predetermined number of adjacent reference patterns and store the smoothed reference patterns in the reference data storage unit.

[0020] One of the detection unit and the movement unit may be fixed relative to the lens, and the other of the detection unit and the movement unit may be fixed relative to the housing. The detection unit may detect the position of the lens relative to the housing.

[0021] According to a second aspect of the present invention, there is provided a position detection device. The position detection device may include an acquisition unit that acquires a magnetic field pattern measured by the magnetic sensor units from a detection target device including a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction, and a mobile unit that is movable relative to the detection unit in a predetermined direction and provides the magnetic sensor units with a magnetic field pattern corresponding to its position relative to the detection unit. The position detection device may include a detection unit that detects whether the position of the mobile unit relative to the detection unit is a position associated with the reference pattern based on a result of comparing the acquired magnetic field pattern with a reference pattern. Each of the plurality of magnetic sensor units may have two or more magnetic sensors. Each of the plurality of magnetic sensor units may include a calculation unit that calculates a detection value corresponding to the magnetic sensor unit in the magnetic field pattern based on output values ​​of the two or more magnetic sensors. The spacing between the two or more magnetic sensors in each of the plurality of magnetic sensor units may be smaller than the spacing between adjacent magnetic sensor units in the plurality of magnetic sensor units.

[0022] According to a third aspect of the present invention, there is provided a position detection system, which may include a detection target device and a position detection device.

[0023] According to a fourth aspect of the present invention, there is provided a position detection method. The position detection method may acquire a magnetic field pattern measured by a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction from a detection target device, and a mobile unit movable in a predetermined direction relative to the detection unit and providing a magnetic field pattern to the plurality of magnetic sensor units according to its position relative to the detection unit. The position detection method may output a reference pattern corresponding to each of a plurality of candidate positions of the mobile unit relative to the detection unit. The position detection method may detect which of the plurality of candidate positions is the position of the mobile unit relative to the detection unit based on a result of comparing the acquired magnetic field pattern with the reference pattern corresponding to each of the plurality of candidate positions.

[0024] According to a fifth aspect of the present invention, there is provided a position detection method. The position detection method may acquire a magnetic field pattern measured by a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction, each of the plurality of magnetic sensor units having two or more magnetic sensors and a calculation unit that calculates a detection value corresponding to the magnetic sensor unit based on output values ​​of the two or more magnetic sensors, where the spacing between the two or more magnetic sensors in each of the plurality of magnetic sensor units is smaller than the spacing between adjacent magnetic sensor units in the plurality of magnetic sensor units. The position detection method may also acquire a magnetic field pattern measured by the plurality of magnetic sensor units from a detection target device including: a detection unit that is movable in a predetermined direction relative to the detection unit and that provides the plurality of magnetic sensor units with a magnetic field pattern corresponding to its position relative to the detection unit; and a mobile unit that is movable in a predetermined direction relative to the detection unit and that provides the plurality of magnetic sensor units with a magnetic field pattern corresponding to its position relative to the detection unit. The position detection method may detect whether the position of the mobile unit relative to the detection unit is a position associated with the reference pattern based on a result of comparing the acquired magnetic field pattern with a reference pattern.

[0025] The present invention6 According to one aspect of the present invention, there is provided a position detection program executed by a computer. The position detection program may cause the computer to function as an acquisition unit that acquires a magnetic field pattern measured by the plurality of magnetic sensor units from a detection target device including a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction, and a mobile unit that is movable in a predetermined direction relative to the detection unit and provides a magnetic field pattern to the plurality of magnetic sensor units according to its position relative to the detection unit. The position detection program may cause the computer to function as a reference pattern output unit that outputs a reference pattern corresponding to each of a plurality of candidate positions of the mobile unit relative to the detection unit. The position detection program may cause the computer to function as a detection unit that detects which of the plurality of candidate positions is the position of the mobile unit relative to the detection unit based on a result of comparing the acquired magnetic field pattern with the reference pattern corresponding to each of the plurality of candidate positions.

[0026] The present invention 7 According to another aspect, there is provided a position detection program executed by a computer. The position detection program may cause the computer to function as an acquisition unit that acquires a magnetic field pattern measured by the magnetic sensor units from a detection target device including: a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction, each of the plurality of magnetic sensor units having two or more magnetic sensors and a calculation unit that calculates a detection value corresponding to the magnetic sensor unit based on output values ​​of the two or more magnetic sensors, where the spacing between the two or more magnetic sensors in each of the plurality of magnetic sensor units is smaller than the spacing between adjacent magnetic sensor units in the plurality of magnetic sensor units; and a mobile unit that is movable in a predetermined direction relative to the detection unit and provides a magnetic field pattern to the plurality of magnetic sensor units according to its position relative to the detection unit. The position detection program may cause the computer to function as a detection unit that detects whether the position of the mobile unit relative to the detection unit is a position associated with the reference pattern based on a result of comparing the acquired magnetic field pattern with a reference pattern.

[0027] The above summary of the invention does not list all of the features of the present invention, and subcombinations of these features may also be inventions. [Brief explanation of the drawings]

[0028] [Figure 1] 1 shows the configuration of a system 10 according to this embodiment. [Figure 2] 1 shows an example of the relationship between the position of the moving unit 60 relative to the detection unit 30 and the magnetic field detection values ​​(average values) obtained by the plurality of calculation units 45-1 to 45-4. [Figure 3] 1 shows an example of the relationship between the position of the moving unit 60 relative to the detection unit 30 and the magnetic field detection values ​​(difference values) obtained by the multiple calculation units 45-1 to 45-4. [Figure 4] 10 shows a position detection flow according to the present embodiment. [Figure 5] 1 shows an example of reference data stored in the reference data storage unit 130 according to this embodiment. [Figure 6] 1 shows an example of the relationship between the position of the mobile unit 60 relative to the detection unit 30 and the distance between the acquired magnetic field pattern and the reference pattern. [Figure 7] 10 shows an imaging process flow of an imaging device according to an example of this embodiment. [Figure 8] 10 shows a flow of creating reference data according to the present embodiment. [Figure 9] 22 illustrates an example computer 2200 in which aspects of the present invention may be embodied, in whole or in part. DETAILED DESCRIPTION OF THE INVENTION

[0029] The present invention will be described below through embodiments of the invention, but the following embodiments do not limit the scope of the invention according to the claims. Furthermore, not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0030] 1 shows the configuration of a system 10 according to this embodiment. The system 10 uses a relatively simple structure that uses multiple magnetic sensor units 35-1 to 35-4, and can detect the position of a moving unit 60, which has a relatively large range of movement, relative to a detection unit 30 by absolute position detection.

[0031] The system 10 includes a detection target device 20, a position detection device 100, and a drive control unit 160. The detection target device 20 has a detection unit 30 and a moving unit 60 that is movable in a predetermined direction relative to the detection unit 30, and is a device whose absolute position is detected by the position detection device 100, and whose position relative to the detection unit 30 is the detection target. For example, the detection target device 20 may be a lens device of an imaging device, and one of the detection unit 30 and the moving unit 60 (e.g., the moving unit 60) may be fixed to a lens (not shown), and the other of the detection unit 30 and the moving unit 60 (e.g., the detection unit 30) may be fixed to a housing of the lens device. Alternatively, the detection target device 20 may be any other device that moves the moving unit 60 within a movable range relative to the detection unit 30.

[0032] The detection unit 30 has a housing 32, a plurality of magnetic sensor units 35-1 to 35-4 (also referred to as "magnetic sensor units 35"), and a drive unit 50. The housing 32 may be, for example, the housing of a lens device. The plurality of magnetic sensor units 35 are arranged at different positions in a predetermined direction. Here, the "predetermined direction" may be the movement direction of the moving unit 60 relative to the detection unit 30, and is also referred to as the "movement direction." In this embodiment, the detection unit 30 has, as an example, four magnetic sensor units 35. Alternatively, the detection unit 30 may have two, three, five or more magnetic sensor units 35.

[0033] The plurality of magnetic sensor units 35 may be arranged along the movement direction, or may be arranged at offset positions in a direction perpendicular to the movement direction. In this embodiment, the plurality of magnetic sensor units 35 are arranged along the movement direction.

[0034] Each of the multiple magnetic sensor units 35 includes two or more magnetic sensors 40 and a calculation unit 45. In this embodiment, the magnetic sensor unit 35-1 includes two magnetic sensors 40-1a-b and a calculation unit 45-1, the magnetic sensor unit 35-2 includes two magnetic sensors 40-2a-b and a calculation unit 45-2, the magnetic sensor unit 35-3 includes two magnetic sensors 40-3a-b and a calculation unit 45-3, and the magnetic sensor unit 35-4 includes two magnetic sensors 40-4a-b and a calculation unit 45-4. Here, the magnetic sensors 40-1a-b, 40-2a-b, 40-3a-b, and 40-4a-b are also referred to as "magnetic sensors 40." The calculation units 45-1-4 are also referred to as "calculation units 45."

[0035] Each magnetic sensor 40 measures the magnetic field at the position where the magnetic sensor 40 is installed, and outputs an output value (for example, a voltage or a current) according to the magnetic field. The magnetic sensor 40 may measure the strength of the magnetic field in the vertical direction in the figure (i.e., the direction of the mobile unit 60 relative to the detection unit 30), or may measure the strength of the magnetic field in other directions as long as it can detect changes in the magnetic field according to the movement of the mobile unit 60.

[0036] Each calculation unit 45 is connected to two or more magnetic sensors 40 included in the magnetic sensor unit 35 in which the calculation unit 45 is provided. Each calculation unit 45 calculates a detection value corresponding to the magnetic sensor unit 35 in the magnetic field pattern based on the output values ​​of the two or more magnetic sensors 40. For example, each calculation unit 45 may calculate the sum or average of the output values ​​of the two or more magnetic sensors 40 as the detection value, or may calculate the difference between the output values ​​of two magnetic sensors 40 included in the two or more magnetic sensors 40 as the detection value.

[0037] The two or more magnetic sensors 40 in each of the multiple magnetic sensor units 35 may be provided adjacent to each other. In this case, the distance between the two or more magnetic sensors 40 in each of the multiple magnetic sensor units 35 is smaller than the distance between adjacent magnetic sensor units 35 in the multiple magnetic sensor units 35. That is, the distance between adjacent magnetic sensors 40 in the same magnetic sensor unit 35 (the distance between magnetic sensor 40-1a and magnetic sensor 40-1b, etc.) is smaller than the distance between adjacent magnetic sensors 40 in adjacent magnetic sensor units 35 (the distance between magnetic sensor 40-1b and magnetic sensor 40-2a, etc.). This allows each magnetic sensor unit 35 to output an appropriate detection value using the local magnetic field at the position where the respective magnetic sensor unit 35 is provided, and makes it possible to detect the position of the mobile unit 60, which has a wide range of motion, using the multiple magnetic sensor units 35 distributed over a wide range in the movement direction of the mobile unit 60.

[0038] Here, the two or more magnetic sensors 40 in each magnetic sensor section 35 may be arranged at different positions in the movement direction of the moving unit 60, or may be arranged at the same position in the movement direction of the moving unit 60. For example, the two or more magnetic sensors 40 may be arranged at different positions in a direction perpendicular to both the movement direction of the moving unit 60 (left-right direction in the drawing) and the direction of the moving unit 60 relative to the detection unit 30 (up-down direction in the drawing) (i.e., a direction perpendicular to the plane of the drawing).

[0039] The driving unit 50 is fixed to the housing 32. The driving unit 50 is an actuator such as an electrostatic actuator, a voice coil motor (VCM), or a piezoelectric actuator. The driving unit 50 is connected to the driving control unit 160 and moves the object 70 to be moved in the movement direction under the control of the driving control unit 160. The driving unit 50 may have a driving coil fixed to the housing 32 and move the object 70 to be moved in the movement direction by generating a magnetic force between the driving coil and a magnet 75. Such a driving coil may have a structure having a winding around the outer periphery of each magnetic sensor unit 35-1.

[0040] The moving unit 60 has a moving object 70 and a magnet 75. The moving object 70 is a component that is moved by the driving unit 50, such as a lens in a lens device. The magnet 75 is fixed to the moving object 70 and applies a magnetic field pattern to the plurality of magnetic sensor units 35 according to its position relative to the detection unit 30. In this embodiment, the magnet 75 has its south poles and north poles arranged alternately along the moving direction of the moving unit 60. Alternatively, the magnet 75 may have any structure (such as an arrangement of south and north poles) that can apply a magnetic field pattern to the plurality of magnetic sensor units 35 according to the movement of the moving unit 60.

[0041] Instead of having the magnet 75, the mobile unit 60 may have any magnetic field changing means that can change the magnetic field pattern applied to the multiple magnetic sensor units 35 in accordance with the movement of the mobile unit 60. For example, the mobile unit 60 may have a magnetic concentrator made of a soft magnetic material, or the like, and the magnetic field generated by a magnet fixed to the housing 32 may be changed in accordance with the position of the mobile unit 60.

[0042] The position detection device 100 includes an acquisition unit 110, a range identification unit 120, a reference data storage unit 130, a reference pattern output unit 140, and a detection unit 150. The acquisition unit 110 is connected to a plurality of magnetic sensor units 35 and acquires magnetic field patterns measured by the plurality of magnetic sensor units 35.

[0043] Here, the "magnetic field pattern" refers to a pattern of combinations of the multiple detection values ​​output by the multiple magnetic sensor units 35, which are obtained by measuring the magnetic field applied to the detection unit 30 according to the position of the mobile unit 60 using the multiple magnetic sensors 40 and converting the values ​​into detection values ​​for each magnetic sensor unit 35. In the example shown in the figure, the magnetic sensor units 35-1 to 35-4 output detection values ​​S1 to S4, so the magnetic field pattern is a set of detection values ​​S1 to S4 (S1, S2, S3, S4). Note that the set of detection values ​​S1 to S4 is a set of different values ​​depending on the distribution of the magnetic field applied to the detection unit 30, and therefore is a collection of values ​​that allows the distribution of the magnetic field applied to the detection unit 30 to be identified, and may also be expressed as a "magnetic field profile."

[0044] The range specifying unit 120 is connected to the acquisition unit 110. The range specifying unit 120 specifies a detection target range for the position of the mobile unit 60 relative to the detection unit 30 as a part of the movable range, based on the magnetic field pattern measured by the multiple magnetic sensor units 35. For example, if the movable range of the mobile unit 60 is 12 mm, the range specifying unit 120 uses the magnetic field pattern to narrow down the range in which the mobile unit 60 is located to, for example, a "range of 3 mm to 6 mm."

[0045] The reference data storage unit 130 stores reference data used to generate reference patterns representing magnetic field patterns to be measured by the multiple magnetic sensor units 35 for each position of the mobile unit 60. The reference pattern output unit 140 is connected to the range identification unit 120 and the reference data storage unit 130. The reference pattern output unit 140 uses the reference data stored in the reference data storage unit 130 to output reference patterns corresponding to one or more candidate positions of the mobile unit 60 relative to the detection unit 30. Here, the reference pattern output unit 140 outputs reference patterns corresponding to one or more candidate positions within the detection target range identified by the range identification unit 120.

[0046] The detection unit 150 is connected to the acquisition unit 110 and the reference pattern output unit 140, and detects the position of the mobile unit 60 relative to the detection unit 30 based on the magnetic field pattern acquired by the acquisition unit 110. For each of one or more reference patterns corresponding to one or more candidate positions output by the reference pattern output unit 140, the detection unit 150 detects whether the position of the mobile unit 60 relative to the detection unit 30 is a position associated with the reference pattern based on a result of comparing the magnetic field pattern with the reference pattern. Here, when the reference pattern output unit 140 outputs a reference pattern corresponding to a candidate position within the detection target range, the detection unit 150 detects which position within the detection target range the position of the mobile unit 60 relative to the detection unit 30 is based on a result of comparing the magnetic field pattern with the reference pattern corresponding to the position within the detection target range.

[0047] The drive control unit 160 is connected to the detection unit 150 in the position detection device 100, and receives the position of the moving unit 60 relative to the detection unit 30 from the detection unit 150. The drive control unit 160 receives a target position of the moving unit 60 from a control unit that controls the system 10, such as a microcontroller of the imaging device, and controls the drive of the drive unit 50 so as to move the moving unit 60 to the target position.

[0048] FIG. 2 shows an example of the relationship between the position of the moving unit 60 relative to the detection unit 30 and the magnetic field detection values ​​(average values) obtained by the calculation units 45-1 to 45-4. In the detection target device 20 shown in this figure, the moving unit 60 has a movable range of 0 to 12 mm relative to the detection unit 30. The detection target device 20 uses a magnet 75 with a length of 8 mm in the movement direction and whose south and north poles change polarity every 2 mm as shown in FIG. 1. Four magnetic sensor units 35 are provided at 3 mm intervals in the movement direction, and two magnetic sensors 40 are provided at 480 μm intervals within each magnetic sensor unit 35. In the example shown in this figure, each magnetic sensor unit 35 outputs the average output value of the two magnetic sensors 40 connected to it as a detection value. This figure is a graph of the detection target device 20 configured in this way, with the horizontal axis representing the position of the moving unit 60 and the vertical axis representing the detection values ​​S1 to S4 output by each magnetic sensor unit 35 at each position. In this figure, the detected values ​​S1 to S4 at each position of the moving unit 60 are values ​​obtained by simulation.

[0049] As shown in this figure, the magnetic field pattern represented by the set of detection values ​​S1 to S4 differs for each position of the mobile unit 60. Therefore, the detection unit 150 can detect the position of the mobile unit 60 by determining which of the sets of detection values ​​S1 to S4 for each position shown in this figure corresponds to the magnetic field pattern acquired from the acquisition unit 110. In this embodiment, the reference pattern output unit 140 generates the sets of detection values ​​S1 to S4 for each position shown in this figure as reference patterns, and the detection unit 150 determines which of the reference patterns generated by the reference pattern output unit 140 matches the magnetic field pattern acquired from the acquisition unit 110, and identifies the position associated with the matched reference pattern as the position of the mobile unit 60. Alternatively, if a conversion function for calculating a position can be obtained from the set of detection values ​​S1 to S4, the detection unit 150 may input the detection values ​​S1 to S4 included in the magnetic field pattern into this conversion function to calculate the position of the mobile unit 60.

[0050] 3 shows an example of the relationship between the position of the moving unit 60 relative to the detection unit 30 and the magnetic field detection values ​​(difference values) detected by the multiple calculation units 45-1 to 45-4. The detection target device 20 in this figure has the same structure of the magnet 75 and the same arrangement of the magnetic sensor units 35 as those in FIG. 2, but differs in that each magnetic sensor unit 35 outputs the difference value between the output values ​​of the two magnetic sensors 40 connected thereto as a detection value.

[0051] As shown in the figure, the magnetic field pattern represented by the set of detection values ​​S1 to S4 differs for each position of the mobile unit 60. Therefore, in the example of the figure, the detection unit 150 can detect the position of the mobile unit 60 by determining to which of the sets of detection values ​​S1 to S4 for each position shown in the figure the magnetic field pattern acquired from the acquisition unit 110 corresponds.

[0052] Here, when the magnetic sensing directions of the two magnetic sensors 40 in each magnetic sensor unit 35 are the same, the average value of the output values ​​of the two magnetic sensors 40 is affected by the disturbance magnetic field, but the difference between the output values ​​of the two magnetic sensors 40 is a value in which the disturbance magnetic field components contained in each output value are offset. Therefore, when such a magnetic sensor unit 35 is used, the calculation unit 45 can output a detection value more suitable for position detection by outputting the difference between the output values ​​of the two magnetic sensors 40 as the detection value. Note that when the magnetic sensing directions of the two magnetic sensors 40 in each magnetic sensor unit 35 are opposite to each other, the calculation unit 45 can output a detection value in which the disturbance magnetic field components are offset by outputting the sum or average of the output values ​​of the two magnetic sensors 40 as the detection value.

[0053] If multiple magnetic sensor units 35 are disposed at different positions in the movement direction of the mobile unit 60 so as to cover the movable range of the mobile unit 60, different magnetic fields are applied to the multiple magnetic sensors 40 depending on the position of the mobile unit 60. Therefore, the multiple magnetic sensors 40 of the multiple magnetic sensor units 35 may be provided at any position in the movement direction of the mobile unit 60 as long as they are disposed at different positions within the movable range of the mobile unit 60. Furthermore, each magnetic sensor unit 35 may have only one magnetic sensor 40, or three or more, and each magnetic sensor unit 35 may have a different number of magnetic sensors 40. Furthermore, if each calculation unit 45 calculates a detection value by an operation that reflects the output value of each connected magnetic sensor 40, it is possible to supply the position detection device 100 with a different magnetic field pattern depending on the position of the mobile unit 60.

[0054] 4 shows a position detection flow according to this embodiment. In step 400 (S400), each of the magnetic sensors 40 measures the magnetic field at the position where the magnetic sensor 40 is provided, and outputs an output value according to the magnetic field. 75 Alternatively, in a configuration in which the object to be moved 70 is moved by generating a magnetic force between another magnet and a drive coil, the drive control unit 160 may stop the generation of the magnetic field by the drive coil during the period in which the magnetic field is measured. In step S410, each of the multiple calculation units 45 calculates a detection value in the magnetic field pattern that corresponds to the magnetic sensor unit 35 including the calculation unit 45, based on the output value of at least one magnetic sensor 40 to which it is connected.

[0055] In step S420, the range specifying unit 120 specifies a detection target range for the position of the mobile unit 60 relative to the detection unit 30 as a part of the movable range based on the magnetic field pattern measured by the multiple magnetic sensor units 35. Based on a combination of multiple detection values ​​included in the acquired magnetic field pattern, the range specifying unit 120 may set a range where a reference pattern similar to the acquired magnetic field pattern may exist as the detection target range, and may exclude from the detection target range a range where a reference pattern similar to the magnetic field pattern does not exist. As an example, the range specifying unit 120 specifies the detection target range as follows.

[0056] (1) Identifying the detection range based on the magnitude relationship of detected values The range specifying unit 120 may specify the detection target range based on the magnitude relationship of each detection value included in the magnetic field pattern. For example, in the example of Fig. 3, if the four detection values ​​of the acquired magnetic field pattern have a magnitude relationship of S1>S2>S4>S3, the range in which the four detection values ​​having such a magnitude relationship can exist is limited to a range in which the position of the mobile unit 60 is approximately 2 to 2.5 mm. Therefore, the range specifying unit 120 may specify the detection target range to be approximately 2 to 2.5 mm.

[0057] Note that the multiple detection values ​​actually detected by the multiple magnetic sensor units 35 deviate slightly from the theoretical values, resulting in a slight deviation in the position where the magnitude relationship changes. Therefore, instead of setting the detection target range exactly within the range where the magnitude relationship determined by the theoretical values ​​of the multiple detection values ​​matches, the range specifying unit 120 may set the detection target range with a certain margin on both sides of the range. For example, if the theoretical range where the magnitude relationship matches the acquired magnetic field pattern is 2 to 2.5 mm, the range specifying unit 120 sets the detection target range to 1.8 to 2.7 mm by adding a margin of, for example, 0.2 mm above and below the range.

[0058] Here, the range specifying unit 120 may specify the detection target range using the magnitude relationship of all the detection values included in the magnetic field pattern, or may specify the detection target range using only the magnitude relationship of some of the detection values. For example, the range specifying unit 120 specifies the detection target range based on only the magnitude relationship between detection values S1 and S2. When S1 > S2, the detection target range is set to 2 to 4 mm, and when S2 < S1, the detection subject range may be set to 0 to 2 mm and 4 to 6 mm. Here, the range specifying unit 120 may specify the detection target range using the magnitude relationship of different detection values for each range. For example, the range specifying unit 120 may use the magnitude relationship between detection values S1 and S2 to specify the detection target range for the range of 0 to 6 mm, and use the magnitude relationship between detection values S3 and S4 to specify the detection target range for the range of 6 to 12 mm.

[0059] In addition, the range specifying unit 120 may specify the detection target range based on whether any one of the plurality of detection values but is the maximum, the minimum, or the nth largest, etc. For example, in FIG. 3, when detection value S1 is the largest among detection values S1 to 4, the range specifying unit 120 sets the vicinity of about 2 to 3.5 mm and 6.5 mm as the detection target range.

[0060] (2) Specifying the detection target range based on the positive or negative of the detection value The range specifying unit 120 may specify the detection target range using the positive or negative of one or more detection values. For example, the range specifying unit 120 uses the combination of the positive and negative of detection values S2 and S3. In FIG. 3, when detection values S2 and S3 are positive, the detection target range may be specified as 0.5 to 1.8 mm, 4.5 to 5.5 mm, 8.2 to 9.5 mm, etc.

[0061] (3) Specifying the detection target range based on the magnitude of the detection value The range specifying unit 120 may specify the detection target range using the magnitude of one or more detection values. For example, the range specifying unit 120 uses the magnitude of detection value S1. In FIG. 3, if the magnitude of detection value S1 is within the range of 100 to 250 mT, the detection target range may be specified as 2 to 3 mm.

[0062] In S430, reference pattern output unit 140 outputs a reference pattern corresponding to one or more candidate positions within the detection target range identified by range identification unit 120. In the position detection flow shown in this figure, each time reference pattern output unit 140 executes S430, it outputs one reference pattern corresponding to each candidate position obtained by dividing the area between the lower limit and upper limit of the detection target range at small intervals. Here, each time reference pattern output unit 140 executes S430, it may select candidate positions in order from the lower limit to the upper limit or from the upper limit to the lower limit of the detection target range, and output a reference pattern corresponding to the selected candidate position. Furthermore, if the detection target range includes multiple ranges that are separated from each other, reference pattern output unit 140 may select candidate positions for each of these multiple ranges in order, for example, from the lower limit to the upper limit.

[0063] In S440, the detection unit 150 compares the magnetic field pattern acquired by the acquisition unit 110 with the reference pattern output from the reference pattern output unit 140. In S450, the detection unit 150 determines whether the position of the mobile unit 60 has been detected based on the comparison result between the magnetic field pattern and the reference pattern. If the detection unit 150 has not detected the position of the mobile unit 60 ("N" in S450), the process proceeds to S430 and performs a comparison using the reference pattern corresponding to the next position. If the detection unit 150 has detected the position of the mobile unit 60 ("Y" in S450), the process proceeds to S460 and outputs the detected position.

[0064] The detection unit 150 according to this embodiment detects which of the multiple candidate positions is the position of the mobile unit 60 relative to the detection unit 30 based on the result of comparing the magnetic field pattern with the reference patterns corresponding to each of the multiple candidate positions output by the reference pattern output unit 140 during the repetition of steps S430 to S450. As an example, the detection unit 150 determines, as the position of the mobile unit 60 relative to the detection unit 30, the candidate position associated with the reference pattern that is closest to the magnetic field pattern among the reference patterns corresponding to each of the multiple candidate positions. In this case, the detection unit 150 may compare the reference pattern corresponding to each candidate position with the magnetic field pattern for all candidate positions within the detection target range, and determine the candidate position after performing the comparison for all candidate positions. In step S460, the detection unit 150 outputs the detected position of the mobile unit 60.

[0065] Alternatively, the detection unit 150 may determine, from among the reference patterns corresponding to each of the multiple candidate positions, a candidate position associated with a reference pattern whose difference from the magnetic field pattern is equal to or smaller than a predetermined standard difference, as the position of the mobile unit 60 relative to the detection unit 30. In this case, the detection unit 150 may compare the reference pattern of the candidate position with the magnetic field pattern while changing the candidate position within the detection target range, and upon finding a reference pattern whose difference from the magnetic field pattern is equal to or smaller than the standard difference, determine the candidate position associated with the reference pattern as the position of the mobile unit 60, interrupt the repetition of S430 to S450, and proceed to S460.

[0066] In addition, in S460, the detection unit 150 may determine the final position of the mobile unit 60 based on the position of the mobile unit 60 detected from the comparison result of the reference pattern and the magnetic field pattern, using the detection value of the magnetic sensor unit 35 associated with that position. For example, the detection unit 150 may determine the proximity of one of a plurality of discrete candidate positions to which the mobile unit 60 is located using the comparison result of the reference pattern and the magnetic field pattern, and may calculate by interpolation where the mobile unit 60 is located between the discrete candidate positions using the magnitude of the detection value from the magnetic sensor unit 35 located in the proximity of the determined position.

[0067] In this case, the detection unit 150 can detect the position of the mobile unit 60 with higher accuracy. The detection unit 150 may also compare the detection value of the magnetic sensor unit 35 associated with the position detected from the comparison result of the reference pattern and the magnetic field pattern with these local approximation formulas (approximation formulas with higher accuracy), or may compare the magnetic field patterns measured by multiple magnetic sensor units 35 with more local reference patterns at small intervals. In this case, the reference data storage unit 130 may further store such local approximation formulas or more detailed reference patterns.

[0068] Furthermore, when the detection unit 150 identifies the magnetic sensor unit 35 associated with the position of the mobile unit 60 from the comparison result between the reference pattern and the magnetic field pattern, and determines the position of the mobile unit 60 using the detection values ​​from the identified one or two magnetic sensor units 35, the detection accuracy of the position of the mobile unit 60 that can be detected from the comparison result between the reference pattern and the magnetic field pattern may be such that one or two magnetic sensor units 35 associated with that position can be identified. In this case, the reference data storage unit 130 may store, in association with each magnetic sensor unit 35, one reference pattern corresponding to a representative position within the position detection range of that magnetic sensor unit 35, or may store reference patterns corresponding to positions at both ends of the detection range, or may store reference patterns corresponding to positions at both ends and at least one intermediate point within the detection range.

[0069] With this type of detection unit 150, the number of reference patterns to be compared with the magnetic field pattern can be reduced compared to when the final position of the mobile unit 60 is determined from the comparison result between the reference pattern and the magnetic field pattern, and the number of times the processing from S430 to S450 is repeated can be reduced. Therefore, the detection unit 150 can shorten the processing time required to detect the position of the mobile unit 60.

[0070] Furthermore, the detection unit 150 may be capable of switching between outputting a position associated with a reference pattern as the position of the mobile unit 60 relative to the detection unit 30, and outputting a final position determined using a detection value by the magnetic sensor unit 35 associated with that position. For example, when relatively low position detection accuracy is acceptable but high-speed position detection is required, the detection unit 150 may be set to a position detection mode that outputs a position associated with a reference pattern in response to an external instruction. When higher position detection accuracy is required, the detection unit 150 may be set to a position detection mode that calculates a final position using a detection value by the magnetic sensor unit 35 for a position associated with a reference pattern in response to an external instruction.

[0071] In the position detection flow described above, the position detection device 100 can identify a candidate position that generates a reference pattern similar to the magnetic field pattern by generating a reference pattern corresponding to each of a plurality of candidate positions and comparing it with the magnetic field pattern acquired from the detection unit 30. In this way, if the position detection device 100 knows the theoretical values ​​or target values ​​of each detection value output by the plurality of magnetic sensor units 35 for each position of the mobile unit 60, it can detect the position of the mobile unit 60 using these values.

[0072] Note that the position detection device 100 does not need to have the range identification unit 120, and the position detection flow in Fig. 4 does not need to include S420. In this case, the reference pattern output unit 140 may output reference patterns corresponding to each of a plurality of candidate positions included in the entire movable range of the mobile unit 60.

[0073] 5 shows an example of reference data stored in the reference data storage unit 130 according to this embodiment. The reference data in this figure includes, for each of a plurality of entries indicated by an index, the position x(i) of the moving unit 60 relative to the detection unit 30 and a reference pattern (S(i)1, S(i)2, ..., S(i)) corresponding to that position. N ) and stores a pair. Here, i is an index number, an integer between 1 and I. x(i) is the position associated with the i-th entry. (S(i)1,S(i)2,...,S(i) N ) is the reference pattern corresponding to the i-th entry.

[0074] In S430 of FIG. 4, the reference pattern output unit 140 selects a position x(i) included in the detection target range measured by the range identification unit 120 from the reference data as a candidate position, and outputs the candidate position x(i) and the reference pattern (S(i)1, S(i)2, ..., S(i)) corresponding to that position. N ) to the detection section 150. The detection section 150 detects the position of the mobile unit 60 relative to the detection unit 30 based on the result of comparing the magnetic field pattern with the reference pattern.

[0075] For example, x(i) may be a real value indicating each position obtained by dividing the movable range of the moving unit 60 into the smallest measurement unit, such as 0.01 mm, and each reference value S(i)1, S(i)2, ..., S(i) of the reference pattern k ,…,S(i) N is the magnetic field detection value S that each magnetic sensor unit 35-k (k=1, . . . , N) should detect when the mobile unit 60 is located at position x(i). k (x) is shown.

[0076] In another example, x(i) may represent each section into which the movable range of the mobile unit 60 is divided, and S(i)1, S(i)2, ..., S(i) k ,…,S(i) N may be a parameter such as a coefficient of an approximation function for calculating the magnetic field detection value to be detected in the section i. For example, the reference value S corresponding to the position x in each section k(x) is the approximate function S k (x)=a k ×x+b k The reference data storage unit 130 may approximate the time interval by a linear expression such as k Parameter a of (x) k ,b k This approximation function S k (x) may be a higher order expression as long as it is a function of the position x, or may be an expression of another form, such as using trigonometric functions as an example.

[0077] If an approximation function is associated with each section, the reference pattern output unit 140 may calculate and output a reference pattern corresponding to each candidate position using the approximation function for the section corresponding to each candidate position. In this case, the reference pattern output unit 140 may first output a reference pattern for each section included in the detection range, using one or more candidate positions as representative candidate positions. In this case, the detection unit 150 first detects which of the representative candidate positions is closest to the position of the mobile unit 60 based on the results of comparing the reference pattern of the representative candidate position in each section with the magnetic field pattern. Next, the reference pattern output unit 140 generates one or more candidate positions within the section including the detected representative candidate position, and the detection unit 150 detects which candidate position is the position of the mobile unit 60 based on the results of comparing the reference pattern corresponding to each candidate position with the magnetic field pattern.

[0078] By storing in the reference data storage unit 130 reference patterns corresponding to each position within the movable range of the mobile unit 60 relative to the detection unit 30, the reference data storage unit 130 can store reference patterns for any magnetic field pattern whose characteristics may vary depending on the arrangement of each magnetic sensor 40, the shape of the magnet 75, and other conditions. This allows the reference pattern output unit 140 to output a reference pattern for any position within the movable range of the mobile unit 60. Furthermore, if an approximation function is associated with each section into which the movable range of the mobile unit 60 is divided and stored in the reference data storage unit 130, each section can be enlarged, provided that the error between the original reference pattern and the reference pattern derived from the approximation function is within an acceptable range, and the size of the reference data can be reduced.

[0079] In S430 of FIG. 4, the reference pattern output unit 140 may smooth a predetermined number of adjacent reference patterns in the reference data, and output the smoothed reference patterns as reference patterns used to detect the position of the moving unit 60 relative to the detection unit 30. For example, the reference pattern output unit 140 may smooth each reference pattern stored in the reference data storage unit 130 in association with each of positions x(i-2) to x(i+2), as a reference pattern corresponding to position x(i) excluding two points at each end of the movable range, and output the smoothed reference pattern to the detection unit 150. Such smoothing may be performed using averaging, linear approximation, approximation using a quadratic function or a higher-order function, or other approximation. This allows the position detection device 100 to suppress a decrease in position detection accuracy even if some reference patterns contain noise or data are missing due to a temporary malfunction or other reasons. Here, the reference pattern output unit 140 may dynamically change the number of adjacent reference patterns used to generate a reference pattern for each position.

[0080] 5, the reference data storage unit 130 stores in each entry a reference pattern used for comparison with the magnetic field patterns output by the multiple magnetic sensor units 35. Alternatively, the reference data storage unit 130 may store in each entry a set of output values ​​to be output by the multiple magnetic sensors 40. In this case, the reference pattern output unit 140 may convert the set of output values ​​stored in the reference data storage unit 130 for each candidate position into a reference pattern by, for example, calculating the difference between the output values ​​corresponding to adjacent magnetic sensors 40, and output the reference pattern.

[0081] Furthermore, if the magnetic field detection value of each magnetic sensor 40 can theoretically be defined as a function of the position x of the mobile unit 60 relative to the detection unit 30, the reference pattern output unit 140 can output a reference pattern corresponding to the candidate position using such a function without using the reference data stored in the reference data storage unit 130. In this case, the position detection device 100 does not need to have the reference data storage unit 130. Furthermore, if an inverse function of such a function can be defined, the detection unit 150 may calculate the position of the mobile unit 60 from the magnetic field pattern acquired by the acquisition unit 110 using such an inverse function.

[0082] Furthermore, the number N of pairs of positions and reference patterns stored in the reference data storage unit 130 may be determined based on the required position detection accuracy, the required processing time for position detection, the data size that can be stored in the reference data storage unit 130, etc. For example, if the required position detection accuracy is lower, N may be made smaller, and if the required position detection accuracy is higher, N may be made larger. Furthermore, if the required processing time for position detection is shorter, N may be made smaller, and if a longer processing time for position detection is acceptable, N may be made larger.

[0083] When the position detection device 100 is used for purposes such as focus adjustment in an imaging device, the position detection device 100 is required to output the accurate current position of the mobile unit 60 after it has moved. In this case, the position detection device 100 may obtain higher position detection accuracy by storing more pairs of positions and reference patterns in the reference data storage unit 130. Furthermore, as described with reference to FIG. 4, the position detection device 100 may identify the magnetic sensor unit 35 associated with the position of the mobile unit 60 from the comparison result between the reference pattern and the magnetic field pattern, and determine the position of the mobile unit 60 using the detection value of the identified magnetic sensor unit 35.

[0084] Furthermore, for example, when the position detection device 100 is used to detect fluctuations in the position of the mobile unit 60 due to external impact or the like, the detection accuracy of the position of the mobile unit 60 may be relatively low. In this case, the position detection device 100 may store fewer pairs of positions and reference patterns in the reference data storage unit 130. For example, the position detection device 100 may reduce the position detection accuracy to an accuracy that allows the magnetic sensor unit 35 corresponding to the position of the mobile unit 60 to be identified, thereby shortening the position detection processing time and repeating position detection at shorter intervals. The position detection device 100 may switch the number of pairs of positions and reference patterns used to detect the position of the mobile unit 60 in response to an external instruction based on the required position detection accuracy and position detection processing time.

[0085] FIG. 6 shows an example of the relationship between the position of the mobile unit 60 relative to the detection unit 30 and the distance between the acquired magnetic field pattern and the reference pattern. The detection unit 150 may use the distance between the magnetic field pattern and the reference pattern as an index representing the closeness or magnitude of the difference between the magnetic field pattern and the reference pattern. In the example shown in this figure, the Minkowski distance is used as this distance. If the number of dimensions is p, then the magnetic field pattern s j and the reference pattern S(x) j The Minkowski distance D(x, p) is expressed by the following equation: where j represents the number of the magnetic sensor unit 35.

number

[0086] When p=1, the Minkowski distance D(x,1) is the Manhattan distance. When p=2, the Minkowski distance D(x,2) is the Euclidean distance. The detection unit 150 may use such Minkowski distance as an index representing the closeness or difference between the magnetic field pattern and the reference pattern, or may use other distances or other indices such as similarity. When distance is used, the smaller the distance between the magnetic field pattern and the reference pattern, the closer the magnetic field pattern and the reference pattern are (the smaller the difference), and the larger the distance between the magnetic field pattern and the reference pattern, the farther the magnetic field pattern and the reference pattern are (the larger the difference).

[0087] This figure shows the distance between the reference pattern and the magnetic field pattern corresponding to each candidate position along the horizontal axis when the mobile unit 60 relative to the detection unit 30 is at position A, 4 mm from the end point of the movable range, and at position B, 10 mm from the end point of the movable range, in the example of Figure 3. For example, when the mobile unit 60 is at position A, the distance between the reference pattern and the magnetic field pattern corresponding to each candidate position within the movable range of 0 to 12 mm changes as the candidate position changes from 0 to 12 mm, as shown by the solid line in the figure. Here, this distance is minimum, or approximately zero, when the candidate position is the same as position A, 4 mm. Therefore, the position detection device 100 generates candidate positions within the movable range of 0 to 12 mm, for example, at 0.01 mm intervals, and compares the reference pattern and the magnetic field pattern corresponding to each candidate position to detect the candidate position corresponding to the reference pattern where the distance is minimum or within a predetermined margin range (e.g., within 10 mm in this figure). This allows the position detection device 100 to detect the position of the mobile unit 60 as being at 4 mm.

[0088] Similarly, when the mobile unit 60 is at position B, the distance between the reference pattern and the magnetic field pattern corresponding to each candidate position within the movable range of 0 to 12 mm is smallest, or almost zero, when the candidate position is 10 mm, the same as position B. Therefore, in the same manner as above, the position detection device 100 can detect that the position of the mobile unit 60 is at a position of 10 mm by detecting the candidate position corresponding to the reference pattern where the distance is smallest or within a predetermined margin range.

[0089] 7 shows an imaging process flow of an imaging device according to an example of this embodiment. This diagram shows the process when the system 10 is an imaging device that has an optical system including a lens as a moving object 70 and moves the lens for zooming. Before entering the imaging process flow of this diagram, the system 10 is powered off or in a sleep state, etc., and the mobile unit 60 can move freely relative to the detection unit 30. Therefore, before entering the imaging process flow of this diagram, it is assumed that the position of the mobile unit 60 relative to the detection unit 30 is unknown.

[0090] In S700, the system 10 is started as an imaging device. In S710, the position detection device 100 in the system 10 detects the position x of the lens relative to the housing 32 by the position detection process shown in Fig. 4, for example. At this time, the position detection device 100 can detect the position x of the lens by absolute position detection, without first moving the lens to a predetermined reference position.

[0091] In S720, the system 10 displays the zoom magnification and the image of the subject when the lens is at position x on a display device such as a display panel. In S730, the system 10 determines whether a zoom operation has been received. Here, a "zoom operation" is an operation to enlarge (increase the focal length of the optical system) or reduce (shorten the focal length of the optical system) the subject.

[0092] When a zoom operation is received, in S740, the control device in the system 10 supplies the drive control unit 160 with a target position of the moving unit 60 for setting the focal length of the optical system to the focal length specified by the zoom operation. The drive control unit 160 controls the drive unit 50 so that the position of the moving unit 60 approaches the target position, thereby moving the moving unit 60 to the target position. The system 10 may continue to move the position of the moving unit 60 to the target position while receiving the zoom operation.

[0093] When the zoom operation is no longer performed, the system 10 performs imaging processing in S750. For example, the system 10 may capture an image formed on an imaging element by an optical system. According to the imaging processing flow described above, the system 10 can detect the lens position x by absolute position detection, so there is no need to temporarily move the lens to the reference position for relative position detection, even immediately after startup.

[0094] In the imaging process flow described above, an example has been shown in which system 10, which is an imaging device, detects the position of and drives moving object 70, which is a zoom lens. Alternatively, system 10 may detect the position of and drive moving object 70, which is a focusing lens, or may detect the position of and drive moving object 70, which is a blur correction lens to suppress image blur caused by vibration of the imaging device.

[0095] Furthermore, after moving the moving object 70 to the target position, the system 10 may detect whether the moving object 70 is maintained at the target position, i.e., whether the moving object 70 has deviated from the target position. To achieve this, the detection unit 150 detects that the position of the moving unit 60 relative to the detection unit 30 is the target position, and then detects whether the moving unit 60 has deviated from the target position based on the result of comparing a reference pattern associated with the target position with sequentially acquired magnetic field patterns. For example, the position detection device 100 may compare a periodically acquired magnetic field pattern with only one or some of the reference patterns associated with the target position, and determine that the moving unit 60 has deviated from the target position if the difference between the magnetic field pattern and the reference pattern exceeds a predetermined reference difference.

[0096] When the system 10 is an imaging device, the system 10 moves a moving object 70 such as a lens to a target position in S730 and S740, and then detects in S750 whether the moving object 70 has moved away from the target position due to a disturbance or the like. If the moving object 70 has moved away from the target position during the imaging process, the system 10 may detect the abnormality and proceed to S710 to redetect the position of the moving object 70, and repeat the processes from S720 to S740.

[0097] 8 shows a reference data creation flow according to this embodiment. In the creation flow shown in this figure, the system 10 measures the magnetic field patterns output by the multiple magnetic sensor units 35 while moving the mobile unit 60, and stores the measured magnetic field patterns as reference patterns in the reference data storage unit 130. The system 10 may execute this creation flow for initial adjustment before shipping from the factory, or may execute this creation flow in response to an instruction to adjust the system 10 after shipping from the factory.

[0098] In S800, the drive control unit 160 moves the moving unit 60 to position x, which is to be set as a candidate position. Because this creation flow is a process for creating reference data used by the detection unit 150 for position detection, the system 10 cannot detect the position of the moving unit 60 using the reference data. Therefore, when the system 10 first executes S800, it moves the moving unit 60 to an end point of the movable range. Then, each time S800 is executed, the system 10 may control the drive unit 50 to drive by a predetermined amount, thereby moving the moving unit 60 by a predetermined pitch. Furthermore, before shipping from the factory, the position of the moving unit 60 relative to the detection unit 30 may be measured by a measurement device not included in the system 10, and the detection unit 150 may move the moving unit 60 to the candidate position using the measurement results of the other measurement device.

[0099] In S810, the acquiring unit 110 acquires the magnetic field pattern S(x) output by the plurality of magnetic sensor units 35 when the mobile unit 60 is at position x. In S820, the acquiring unit 110 converts the magnetic field pattern S(x) into data of an entry in the reference data corresponding to position x, and stores the data in the reference data storage unit 130. When the reference data stores the reference pattern itself, the acquiring unit 110 stores the magnetic field pattern S(x) as the reference pattern in the reference data storage unit 130 in association with position x. When the reference data stores each magnetic field detection value S(x) in each section, j When storing the approximate function of each magnetic field detection value S(x) included in the magnetic field pattern S(x), the acquisition unit 110 j Each magnetic field detection value S(x) j The approximation function is calculated, and the parameters of the approximation function are stored in the reference data storage unit 130.

[0100] In S830, if the system 10 has completed the creation of reference data for all positions within the movable range, the system 10 ends this creation flow. If there are any positions for which the system 10 has not completed the creation of reference data, the system 10 proceeds to S800 and performs adjustment at the next position.

[0101] By using the creation flow shown in this figure, the system 10 can generate a reference pattern using the magnetic field pattern observed at each position in the actual object, thereby eliminating the influence of differences in the magnetic field pattern unique to each individual device 20 to be detected, and reducing errors in position detection.

[0102] In the reference data creation process, the acquisition unit 110 may acquire the magnetic field pattern at each position of the mobile unit 60 relative to the detection unit 30 as a reference pattern, smooth a predetermined number of adjacent reference patterns for each position, and store the smoothed reference patterns in the reference data storage unit 130. For example, for each position x(i) excluding two points at each end of the movable range, the acquisition unit 110 may smooth five reference patterns acquired for five adjacent positions x(i-2) to x(i+2) and store the smoothed reference patterns in the reference data storage unit 130. This reduces errors in the reference patterns stored in the reference data storage unit 130 even if noise is included in the reference patterns acquired at some positions due to a temporary malfunction or the like in S810. The acquisition unit 110 may dynamically change the number of adjacent reference patterns used to generate a reference pattern for each position.

[0103] 1 to 8 show the case where the movement of the moving unit 60 relative to the detection unit 30 is in one dimension. Alternatively, the detection target device 20 may move the moving unit 60 in multiple dimensions (two or three dimensions) relative to the detection unit 30. In this case, the detection target device 20 may have a pair of the detection unit 30 and the moving unit 60 that are relatively movable in the x-axis direction, for example, and the moving object 70 carried by the moving unit 60 may include a pair of the detection unit and the moving unit that are relatively movable in the y-axis direction.

[0104] Alternatively, the detection unit 30 may have multiple magnetic sensor units 35 arranged at different positions in two or three dimensions, and the mobile unit 60 may have magnets 75 that provide different magnetic field patterns to the multiple magnetic sensor units 35 at each position within the two or three-dimensional movable range. For example, the magnets 75 may include a magnet with south and north poles arranged alternately in the x-axis direction and a magnet with south and north poles arranged alternately in the y-axis direction. The reference pattern output unit 140 may output reference patterns corresponding to multiple two or three-dimensional candidate positions, and the detection unit 150 may detect, as the position of the mobile unit 60, a candidate position associated with a reference pattern, etc., that is closest to the magnetic field pattern acquired by the acquisition unit 110, among the reference patterns corresponding to the multiple candidate positions.

[0105] Various embodiments of the present invention may be described with reference to flowcharts and block diagrams, where the blocks may represent (1) stages of a process in which operations are performed or (2) sections of an apparatus responsible for performing the operations. Particular stages and sections may be implemented by dedicated circuitry, programmable circuitry provided with computer-readable instructions stored on a computer-readable medium, and / or a processor provided with computer-readable instructions stored on a computer-readable medium. Dedicated circuitry may include digital and / or analog hardware circuitry, and may include integrated circuits (ICs) and / or discrete circuits. Programmable circuitry may include reconfigurable hardware circuitry, including logical AND, OR, XOR, NAND, NOR, and other logical operations, flip-flops, registers, memory elements such as field programmable gate arrays (FPGAs), programmable logic arrays (PLAs), and the like.

[0106] A computer-readable medium may include any tangible device capable of storing instructions that are executed by an appropriate device, such that the computer-readable medium having instructions stored thereon comprises an article of manufacture containing instructions that can be executed to create means for performing the operations specified in the flowcharts or block diagrams. Examples of computer-readable media may include electronic, magnetic, optical, electromagnetic, and semiconductor storage media. More specific examples of computer-readable media may include floppy disks, diskettes, hard disks, random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EPROM or flash memory), electrically erasable programmable read-only memory (EEPROM), static random access memory (SRAM), compact disc read-only memory (CD-ROM), digital versatile disc (DVD), Blu-ray disc, memory stick, integrated circuit card, and the like.

[0107] The computer readable instructions may include either assembler instructions, Instruction Set Architecture (ISA) instructions, machine instructions, machine-dependent instructions, microcode, firmware instructions, state-setting data, or source or object code written in any combination of one or more programming languages, including object-oriented programming languages ​​such as Smalltalk®, JAVA®, C++, etc., and conventional procedural programming languages ​​such as the “C” programming language or similar programming languages.

[0108] The computer-readable instructions may be provided to a processor or programmable circuitry of a programmable data processing apparatus, such as a general-purpose computer, special-purpose computer, or other computer, either locally or over a wide-area network (WAN) such as a local area network (LAN), the Internet, etc., which executes the computer-readable instructions to create means for performing the operations specified in the flowcharts or block diagrams. Examples of processors include computer processors, processing units, microprocessors, digital signal processors, controllers, microcontrollers, etc.

[0109] 9 illustrates an example of a computer 2200 in which aspects of the present invention may be embodied, in whole or in part. Programs installed on the computer 2200 may cause the computer 2200 to function as or perform operations associated with an apparatus or one or more sections of the apparatus according to embodiments of the present invention, and / or to perform a process or steps of a process according to embodiments of the present invention. Such programs may be executed by the CPU 2212 to cause the computer 2200 to perform specific operations associated with some or all of the blocks of the flowcharts and block diagrams described herein.

[0110] A computer 2200 according to this embodiment includes a CPU 2212, a RAM 2214, a graphics controller 2216, and a display device 2218, which are interconnected by a host controller 2210. The computer 2200 also includes input / output units such as a communication interface 2222, a hard disk drive 2224, a DVD-ROM drive 2226, and an IC card drive, which are connected to the host controller 2210 via an input / output controller 2220. The computer also includes legacy input / output units such as a ROM 2230 and a keyboard 2242, which are connected to the input / output controller 2220 via an input / output chip 2240.

[0111] The CPU 2212 operates according to programs stored in the ROM 2230 and RAM 2214, thereby controlling each unit. The graphics controller 2216 acquires image data generated by the CPU 2212 into a frame buffer or the like provided in the RAM 2214 or into the graphics controller 2216 itself, and causes the image data to be displayed on the display device 2218.

[0112] The communications interface 2222 communicates with other electronic devices via a network. The hard disk drive 2224 stores programs and data used by the CPU 2212 in the computer 2200. The DVD-ROM drive 2226 reads programs or data from the DVD-ROM 2201 and provides the programs or data to the hard disk drive 2224 via the RAM 2214. The IC card drive reads programs and data from an IC card and / or writes programs and data to an IC card.

[0113] The ROM 2230 stores therein a boot program or the like that is executed by the computer 2200 upon activation, and / or programs that depend on the hardware of the computer 2200. The input / output chip 2240 may also connect various input / output units to the input / output controller 2220 via a parallel port, a serial port, a keyboard port, a mouse port, etc.

[0114] The programs are provided by a computer-readable medium such as a DVD-ROM 2201 or an IC card. The programs are read from the computer-readable medium, installed in the hard disk drive 2224, RAM 2214, or ROM 2230, which are also examples of computer-readable media, and executed by the CPU 2212. Information processing described in these programs is read by the computer 2200, and brings about cooperation between the programs and the various types of hardware resources described above. An apparatus or method may be configured by realizing information manipulation or processing in accordance with the use of the computer 2200.

[0115] For example, when communication is performed between the computer 2200 and an external device, the CPU 2212 may execute a communication program loaded into the RAM 2214 and instruct the communication interface 2222 to perform communication processing based on the processing described in the communication program. Under the control of the CPU 2212, the communication interface 2222 reads transmission data stored in a transmission buffer processing area provided in the RAM 2214, the hard disk drive 2224, the DVD-ROM 2201, or a recording medium such as an IC card, and transmits the read transmission data to the network, or writes reception data received from the network to a reception buffer processing area or the like provided on the recording medium.

[0116] The CPU 2212 may also cause all or a necessary portion of a file or database stored on an external recording medium such as the hard disk drive 2224, the DVD-ROM drive 2226 (DVD-ROM 2201), an IC card, etc. to be read into the RAM 2214, and perform various types of processing on the data on the RAM 2214. The CPU 2212 then writes back the processed data to the external recording medium.

[0117] Various types of information, such as various types of programs, data, tables, and databases, may be stored on the recording medium and may undergo information processing. The CPU 2212 may perform various types of processing on data read from the RAM 2214, including various types of operations, information processing, conditional judgment, conditional branching, unconditional branching, information search / replacement, etc., as described throughout this disclosure and specified by the instruction sequences of the programs, and write the results back to the RAM 2214. The CPU 2212 may also search for information in a file, database, etc. on the recording medium. For example, if multiple entries each having an attribute value of a first attribute associated with an attribute value of a second attribute are stored on the recording medium, the CPU 2212 may search for an entry that matches a condition specified by the attribute value of the first attribute from among the multiple entries, read the attribute value of the second attribute stored in the entry, and thereby obtain the attribute value of the second attribute associated with the first attribute that satisfies a predetermined condition.

[0118] The above-described programs or software modules may be stored in a computer-readable medium on or near the computer 2200. A recording medium such as a hard disk or RAM provided in a server system connected to a dedicated communication network or the Internet can also be used as a computer-readable medium, thereby providing the programs to the computer 2200 via the network.

[0119] Although the present invention has been described above using embodiments, the technical scope of the present invention is not limited to the scope described in the above embodiments. It will be apparent to those skilled in the art that various modifications and improvements can be made to the above embodiments. It is clear from the claims that such modifications and improvements can also be included within the technical scope of the present invention.

[0120] It should be noted that the execution order of each process, such as operations, procedures, steps, and stages, in the devices, systems, programs, and methods shown in the claims, specifications, and drawings is not specifically stated as "before," "prior to," etc., and that the processes can be performed in any order unless the output of a previous process is used in a subsequent process. Even if the operational flow in the claims, specifications, and drawings is described using "first," "next," etc. for convenience, this does not mean that the processes must be performed in this order. [Explanation of symbols]

[0121] 10 Systems 20 Device to be detected 30 Detection Unit 32 Case 35-1~4 Magnetic sensor section 40-1a~b Magnetic sensor 40-2a~b Magnetic sensor 40-3a~b Magnetic sensor 40-4a~b Magnetic sensor 45-1~4 Calculation section 50 Drive unit 60 Mobile Units 70 Moving Objects 75 Magnet 100 Position detection device 110 Acquisition Department 120 Range specification part 130 Reference data storage unit 140 Reference pattern output unit 150 Detector 160 Drive control unit 2200 Computer 2201 DVD-ROM 2210 host controller 2212 CPU 2214 RAM 2216 Graphics Controller 2218 Display Device 2220 Input / Output Controller 2222 communication interface 2224 hard disk drive 2226 DVD-ROM drive 2230 ROM 2240 I / O chip 2242 keyboard

Claims

1. an acquisition unit that acquires the magnetic field pattern measured by the plurality of magnetic sensor units from a detection target device that includes a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction, and a moving unit that is movable relative to the detection unit in the predetermined direction and provides the plurality of magnetic sensor units with a magnetic field pattern according to their positions relative to the detection unit; a reference pattern output unit that outputs a reference pattern corresponding to each of a plurality of candidate positions of the mobile unit relative to the detection unit; a detection unit that detects which of the plurality of candidate positions is the position of the mobile unit relative to the detection unit based on a result of comparing the acquired magnetic field pattern with the reference patterns corresponding to each of the plurality of candidate positions; a range specifying unit that specifies a detection range of the position of the mobile unit relative to the detection unit to a part of a movable range based on the magnetic field patterns measured by the plurality of magnetic sensor units; Equipped with The detection unit detects a position within the detection range of the mobile unit relative to the detection unit based on a result of comparing the magnetic field pattern with a reference pattern corresponding to a position within the detection range. Position detection device.

2. Each of the plurality of magnetic sensor units two or more magnetic sensors; a calculation unit that calculates a detection value corresponding to the magnetic sensor unit in the magnetic field pattern based on the output value of each of the two or more magnetic sensors; The position detection device according to claim 1 , further comprising:

3. The position detection device according to claim 2 , wherein the calculation unit calculates a difference between output values ​​of the magnetic sensors included in the two or more magnetic sensors as the detection value.

4. 4. The position detection device according to claim 2, wherein the distance between the two or more magnetic sensors in each of the plurality of magnetic sensor units is smaller than the distance between adjacent magnetic sensor units in the plurality of magnetic sensor units.

5. 5. The position detection device according to claim 1, wherein the detection unit determines the candidate position associated with the reference pattern that is closest to the magnetic field pattern among the reference patterns corresponding to each of the plurality of candidate positions as the position of the mobile unit relative to the detection unit.

6. 5. The position detection device according to claim 1, wherein the detection unit determines, among the reference patterns corresponding to each of the plurality of candidate positions, a candidate position associated with a reference pattern whose difference from the magnetic field pattern is less than a predetermined standard difference as the position of the mobile unit relative to the detection unit.

7. an acquisition unit that acquires the magnetic field pattern measured by the plurality of magnetic sensor units from a detection target device that includes a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction, and a moving unit that is movable relative to the detection unit in the predetermined direction and provides the plurality of magnetic sensor units with a magnetic field pattern according to their positions relative to the detection unit; a detection unit that detects whether or not a position of the mobile unit relative to the detection unit is a position associated with the reference pattern based on a result of comparing the acquired magnetic field pattern with a reference pattern; Equipped with Each of the plurality of magnetic sensor units two or more magnetic sensors; a calculation unit that calculates a detection value corresponding to the magnetic sensor unit in the magnetic field pattern based on the output value of each of the two or more magnetic sensors; and a distance between the two or more magnetic sensors in each of the plurality of magnetic sensor units is smaller than a distance between adjacent magnetic sensor units in the plurality of magnetic sensor units; a range specifying unit that specifies a detection range of the position of the mobile unit relative to the detection unit to a part of a movable range based on the magnetic field patterns measured by the plurality of magnetic sensor units; The detection unit detects a position within the detection range of the mobile unit relative to the detection unit based on a result of comparing the magnetic field pattern with a reference pattern corresponding to a position within the detection range. Position detection device.

8. A position detection device as described in Claim 7, further comprising a reference pattern output unit that outputs the reference pattern.

9. The position detection device according to claim 1 , wherein the range specifying unit specifies the detection target range based on a magnitude relationship between the detection values ​​included in the magnetic field pattern.

10. A position detection device described in any one of claims 1 to 6 and 8, wherein the range determination unit determines the detection target range based on the positive or negative of each detection value included in the magnetic field pattern.

11. A position detection device described in any one of claims 1 to 6 and 8, wherein the range determination unit determines the detection target range based on the magnitude of each detection value included in the magnetic field pattern.

12. A position detection device described in any one of claims 1 to 6 and 8 to 11, wherein the detection unit, upon detecting that the position of the mobile unit relative to the detection unit is a position corresponding to the reference pattern, determines the final position of the mobile unit relative to the detection unit using the detection value of the magnetic sensor unit corresponding to that position.

13. The position detection device according to claim 12 , wherein the detection unit is capable of switching between outputting the position associated with the reference pattern or outputting the final position as the position of the mobile unit relative to the detection unit.

14. A position detection device described in any one of claims 1 to 6 and 8 to 13, wherein the detection unit detects that the position of the mobile unit relative to the detection unit is a target position, and then detects whether the mobile unit has moved away from the target position based on the results of comparing a reference pattern corresponding to the target position with the magnetic field pattern.

15. A position detection device described in any one of claims 1 to 6 and 8 to 14, further comprising a reference data memory unit that stores reference data including multiple pairs of the position of the mobile unit relative to the detection unit and the reference pattern corresponding to the position.

16. A position detection device as described in Claim 15, wherein the reference data storage unit stores the reference pattern corresponding to a representative position within the position detection range of the magnetic sensor unit in association with each of the multiple magnetic sensor units, stores the reference pattern corresponding to each position at both ends within the position detection range of the magnetic sensor unit, or stores reference patterns corresponding to each position at both ends and at least one intermediate point within the position detection range of the magnetic sensor unit.

17. The magnetic field pattern is a pattern of a combination of a plurality of detection values ​​measured by the plurality of magnetic sensor units, a movable range of the moving unit relative to the detection unit is divided into a plurality of sections; The reference data storage unit stores parameters of an approximation function for calculating a detection value to be detected in each of the plurality of sections, in association with each of the plurality of sections. The position detection device according to claim 15.

18. The position detection device according to claim 15, wherein the reference pattern output unit smoothes a predetermined number of the reference patterns in the reference data whose corresponding positions are adjacent, and outputs the smoothed reference patterns as the reference patterns used to detect the position of the mobile unit relative to the detection unit.

19. In the reference data creation process, the acquisition unit: obtaining the magnetic field pattern at each position of the mobile unit relative to the detection unit as the reference pattern; For each position, a predetermined number of adjacent reference patterns are smoothed and stored in the reference data storage unit. The position detection device according to claim 15.

20. one of the detection unit and the moving unit is fixed relative to the lens; the other of the detection unit and the moving unit is fixed to a housing; The position detection device according to claim 1 , wherein the detection unit detects the position of the lens relative to the housing.

21. A position detection system comprising the detection target device and the position detection device according to any one of claims 1 to 20.

22. a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction; and a moving unit that is movable in the predetermined direction relative to the detection unit and provides the plurality of magnetic sensor units with magnetic field patterns corresponding to their positions relative to the detection unit, the magnetic field patterns being acquired from the detection target device, the magnetic field patterns being measured by the plurality of magnetic sensor units; outputting a reference pattern corresponding to each of a plurality of candidate positions of the mobile unit relative to the detection unit; Based on a result of comparing the acquired magnetic field pattern with the reference patterns corresponding to the plurality of candidate positions, it is determined which of the plurality of candidate positions is the position of the mobile unit relative to the detection unit.

1. A position detection method, comprising: specifying a detection range of the position of the mobile unit relative to the detection unit as a part of a movable range based on the magnetic field patterns measured by the plurality of magnetic sensor units; Based on a result of comparing the magnetic field pattern with the reference pattern corresponding to a position within the detection range, the position of the mobile unit relative to the detection unit is detected as a position within the detection range. Location detection methods.

23. a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction, each of the plurality of magnetic sensor units having two or more magnetic sensors and a calculation unit that calculates a detection value corresponding to the magnetic sensor unit based on output values ​​of the two or more magnetic sensors, and a distance between the two or more magnetic sensors in each of the plurality of magnetic sensor units being smaller than a distance between adjacent magnetic sensor units in the plurality of magnetic sensor units; and a moving unit that is movable in the predetermined direction relative to the detection unit and that gives the plurality of magnetic sensor units a magnetic field pattern corresponding to their position relative to the detection unit, Based on a result of comparing the acquired magnetic field pattern with a reference pattern, it is detected whether or not the position of the mobile unit relative to the detection unit is a position associated with the reference pattern.

1. A position detection method, comprising: specifying a detection range of the position of the mobile unit relative to the detection unit as a part of a movable range based on the magnetic field patterns measured by the plurality of magnetic sensor units; Based on a result of comparing the magnetic field pattern with the reference pattern corresponding to a position within the detection range, the position of the mobile unit relative to the detection unit is detected as a position within the detection range. Location detection methods.

24. The method is executed by a computer, causing the computer to: an acquisition unit that acquires the magnetic field pattern measured by the plurality of magnetic sensor units from a detection target device that includes a detection unit having a plurality of magnetic sensor units arranged at different positions in a predetermined direction, and a moving unit that is movable relative to the detection unit in the predetermined direction and provides the plurality of magnetic sensor units with a magnetic field pattern according to their positions relative to the detection unit; a reference pattern output unit that outputs a reference pattern corresponding to each of a plurality of candidate positions of the mobile unit relative to the detection unit; a detection unit that detects which of the plurality of candidate positions is the position of the mobile unit relative to the detection unit based on a result of comparing the acquired magnetic field pattern with the reference patterns corresponding to each of the plurality of candidate positions; a range specifying unit that specifies a detection range of the position of the mobile unit relative to the detection unit to a part of a movable range based on the magnetic field patterns measured by the plurality of magnetic sensor units; and make it work, The detection unit detects a position within the detection range of the mobile unit relative to the detection unit based on a result of comparing the magnetic field pattern with a reference pattern corresponding to a position within the detection range. Location detection program.

25. The method is executed by a computer, causing the computer to: an acquisition unit that acquires the magnetic field pattern measured by the plurality of magnetic sensor units from a detection target device that includes a detection unit having a plurality of magnetic sensor units arranged at different positions from each other in a predetermined direction, each of the plurality of magnetic sensor units having two or more magnetic sensors and a calculation unit that calculates a detection value corresponding to the magnetic sensor unit based on output values ​​of the two or more magnetic sensors, and a moving unit that is movable relative to the detection unit in the predetermined direction and that provides the plurality of magnetic sensor units with a magnetic field pattern corresponding to their position relative to the detection unit; a detection unit that detects whether a position of the mobile unit relative to the detection unit is a position associated with the reference pattern based on a result of comparing the acquired magnetic field pattern with a reference pattern; a range specifying unit that specifies a detection range of the position of the mobile unit relative to the detection unit to a part of a movable range based on the magnetic field patterns measured by the plurality of magnetic sensor units; and make it work, The detection unit detects a position within the detection range of the mobile unit relative to the detection unit based on a result of comparing the magnetic field pattern with a reference pattern corresponding to a position within the detection range. Location detection program.

Images