Event detection method, event detection system and program

Abstract

The present invention provides an event detection method, an event detection system and a program. The event detection method detects an event corresponding to the position of a magnetic field generating unit by using a magnetic sensor to detect a predetermined magnetic field of more than two axes generated by a magnetic field generating unit. The event detection method includes the following stages: obtaining the event generation position based on the magnetic field detected by the magnetic sensor; selecting a detection axis for detecting the event based on the event generation position; calculating a trigger threshold on the detection axis corresponding to the event generation position; and obtaining a trigger signal indicating that the magnetic field detected by the magnetic sensor and the trigger threshold satisfy specified conditions.

Description

Technical Field

[0001] The present invention relates to an event detection method, an event detection system and a program. Background Art

[0002] Patent document 1 states that "a position sensor is provided that can detect the movement of a detection object by using a single detection unit even if the movement amount of the detection object increases." Patent document 2 states that "a position detection sensor is provided that has a linear output for a long detection distance and can detect a position with high detection accuracy."

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2019-2835

[0006] Patent Document 2: Japanese Patent Application Publication No. 2003-167627 Summary of the invention

[0007] In the first embodiment of the present invention, an event detection method is provided, which detects an event corresponding to the position of a magnetic field generating unit by using a magnetic sensor to detect a predetermined magnetic field of more than two axes generated by a magnetic field generating unit. The event detection method includes the following stages: obtaining the event generation position based on the magnetic field detected by the magnetic sensor; selecting a detection axis for detecting the event based on the event generation position; calculating a trigger threshold on the detection axis corresponding to the event generation position; and receiving a trigger signal indicating that the magnetic field detected by the magnetic sensor and the trigger threshold satisfy specified conditions.

[0008] In a second embodiment of the present invention, an event detection system is provided, which comprises: a magnetic field generating unit, which generates a predetermined magnetic field; a magnetic sensor, which is used to detect the magnetic field generated by the magnetic field generating unit; and a processing unit, which is used to process the signal detected by the magnetic sensor, wherein the processing unit has: an acquisition unit, which acquires the event occurrence position based on the magnetic field detected by the magnetic sensor; a selection unit, which selects a detection axis for detecting the event based on the event occurrence position; and a calculation unit, which calculates a trigger threshold on the detection axis corresponding to the event occurrence position, and the magnetic sensor has an output unit, which outputs a trigger signal indicating that the detected magnetic field and the trigger threshold satisfy specified conditions.

[0009] In a third aspect of the present invention, there is provided a program for causing a computer to execute the event detection method described in the first aspect of the present invention.

[0010] In addition, the above summary of the invention does not list all the features of the present invention. In addition, sub-combinations of these feature groups can also constitute other inventions. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1A is a block diagram showing an overview of the event detection system 100 .

[0012] Figure 1B The magnetic sensor 20 and the processing unit 30 are shown in more detail.

[0013] Figure 2A An example of a method of arranging the magnetic field generating unit 10 and the magnetic sensor 20 is shown.

[0014] Figure 2B An example of a method of arranging the magnetic field generating unit 10 and the magnetic sensor 20 is shown.

[0015] Figure 2C An example of a method of arranging the magnetic field generating unit 10 and the magnetic sensor 20 is shown.

[0016] Figure 3A The state where the magnetic field generating unit 10 is arranged at the reference position P0 is shown.

[0017] Figure 3B The state where the magnetic field generating unit 10 is arranged at the event occurrence position Pe is shown.

[0018] Figure 3C The magnetic field waveform according to the position of the magnetic field generating unit 10 is shown.

[0019] Figure 3D Shown with Figure 3C The changes in magnetic flux density and trigger signal corresponding to the magnetic field waveform.

[0020] Figure 4A An example of a threshold determination method using a biaxial magnetic field is shown.

[0021] Figure 4B An example of a method of arranging the magnetic field generating unit 10 and the magnetic sensor 20 is shown.

[0022] Figure 4C An example of a method of arranging the magnetic field generating unit 10 and the magnetic sensor 20 is shown.

[0023] Figure 4D An example of a threshold determination method using a biaxial magnetic field is shown.

[0024] Figure 5 A comparative example of a threshold determination method using a uniaxial magnetic field is shown.

[0025] Figure 6 A more specific example of a threshold determination method is shown.

[0026] Fig. 7A A more specific example of a threshold determination method is shown.

[0027] Figure 7B A more specific example of a threshold determination method is shown.

[0028] Figure 7C A more specific example of a threshold determination method is shown.

[0029] Fig.7D A more specific example of a threshold determination method is shown.

[0030] Fig. 7E A more specific example of a threshold determination method is shown.

[0031] Fig. 8A A more specific example of a threshold determination method is shown.

[0032] Figure 8B A more specific example of a threshold determination method is shown.

[0033] Figure 8C A more specific example of a threshold determination method is shown.

[0034] Fig.8D A more specific example of a threshold determination method is shown.

[0035] Fig. 9 An example of the operation flow of the event detection system 100 is shown.

[0036] Fig.10 An example of the configuration of the event detection system 100 is shown.

[0037] Fig.11 An example of a computer 2200 is shown that can implement various aspects of the present invention in whole or in part. DETAILED DESCRIPTION

[0038] The present invention will be described below by way of the embodiments of the invention, but the following embodiments do not limit the invention as defined in the claims. In addition, all combinations of features described in the embodiments are not necessarily essential to the solution of the invention.

[0039] Figure 1A 2 is a block diagram showing an overview of the event detection system 100 . The event detection system 100 includes a magnetic field generating unit 10 , a magnetic sensor 20 , and a processing unit 30 .

[0040] The magnetic field generating unit 10 generates a predetermined magnetic field. For example, the magnetic field generating unit 10 includes a two-pole magnet, and the two-pole magnet includes an N pole and an S pole arranged in a predetermined direction. The magnetic field generating unit 10 generates a magnetic field with a predetermined magnetic field waveform according to the magnetization direction of the magnet. The magnetic field generating unit 10 can move in a predetermined direction to change the magnetic field waveform.

[0041] The magnetic sensor 20 is used to detect the magnetic field generated by the magnetic field generating unit 10. The magnetic sensor 20 detects the magnetic field of at least two or more detection axes. The magnetic sensor 20 in this example is a multi-axis magnetic sensor capable of detecting magnetic fields of more than two axes. However, the magnetic sensor 20 can also detect magnetic fields of more than two axes by having multiple single-axis sensors. The magnetic sensor 20 obtains measurement data obtained by detecting the magnetic flux density of the magnetic field of more than two axes. When the obtained measurement data meets a predetermined condition, the magnetic sensor 20 generates a trigger signal. The trigger signal is an interrupt signal for notifying the magnetic sensor 20 of a state change.

[0042] The processing unit 30 is used to process the signal detected by the magnetic sensor 20. The processing unit 30 performs serial communication with the magnetic sensor 20 and receives the measurement data from the magnetic sensor 20. In addition, the processing unit 30 changes the internal state using the trigger signal from the magnetic sensor 20. For example, the processing unit 30 changes the device provided with the processing unit 30 from the standby state to the startup state according to the receipt of the trigger signal.

[0043] The event detection system 100 generates a trigger signal based on the detection of an event corresponding to the relative positional relationship between the magnetic field generator 10 and the magnetic sensor 20. The event detection system 100 of this example generates a trigger signal when the magnetic field generator 10 moves to a predetermined position, thereby executing a predetermined action.

[0044] In one example, the event detection system 100 is mounted on a mobile terminal such as a smartphone with a retractable display (e.g., a roll-up screen phone), and outputs a trigger signal for switching the display of the display according to the display being retracted to a predetermined position. In addition, the event detection system 100 can also switch the smartphone from a standby state to a start state according to the detection of an event. In addition, the event detection system 100 can change from a start state to a standby state if there is no operation within a predetermined period.

[0045] Figure 1B The following is a more specific configuration of the magnetic sensor 20 and the processing unit 30. The magnetic sensor 20 of this example includes a detection unit 22 and an output unit 24. The processing unit 30 includes an acquisition unit 32, a selection unit 34, and a calculation unit 36.

[0046] The detection unit 22 detects the magnetic field generated by the magnetic field generating unit 10. The detection unit 22 outputs the measurement data (Bx, By, Bz) of the detected magnetic field to the detection unit 22 or the processing unit 30. Bx, By, and Bz represent the magnetic flux density in the X-axis direction, the Y-axis direction, and the Z-axis direction, respectively. The detection unit 22 of this example detects the magnetic flux density in the three-axis direction as the measurement data, and can also detect the magnetic flux density in the two-axis direction.

[0047] The acquisition unit 32 acquires the measurement data (Bx, By, Bz) from the magnetic sensor 20. For example, the acquisition unit 32 acquires the measurement data when the magnetic field generator 10 is located at a predetermined reference position P0. The reference position P0 may be any position where the magnetic sensor 20 can detect the position of the magnetic field generator 10.

[0048] In addition, the acquisition unit 32 can acquire information required for selecting the detection axis or calculating the trigger threshold, such as the event generation position Pe of the magnetic field generating unit 10. The acquisition method of the event generation position Pe will be described later. The acquisition unit 32 outputs the acquired event generation position Pe to the selection unit 34 and the calculation unit 36. The acquisition unit 32 can also acquire information such as the event generation position Pe from a storage unit provided in the processing unit 30.

[0049] In addition, the acquisition unit 32 can acquire the detectable area and the undetectable area corresponding to the position of the magnetic field generating unit 10 according to the detection axis. The detectable area is an area where the trigger threshold can be detected on the corresponding detection axis. The undetectable area is an area where the trigger threshold cannot be detected on the corresponding detection axis. The situation where the trigger threshold cannot be detected, for example, refers to the situation where the position of the magnetic field generating unit 10 cannot be determined based on the output magnetic flux density. It can be that each of the multiple detection axes is selected to have a detectable area and an undetectable area in a different area.

[0050] The selection unit 34 selects a detection axis for detecting an event based on the event generation position Pe. For example, the selection unit 34 selects a first axis parallel to a predetermined first direction in which the magnetic field generating unit 10 moves, or a second axis orthogonal to the first axis as the detection axis. The selection unit 34 selects the detection axis in such a way that the position of the magnetic field generating unit 10 belongs to the detectable area. The specific method for selecting the detection axis will be described later.

[0051] The calculation unit 36 ​​calculates a trigger threshold value corresponding to the event occurrence position Pe on the detection axis. The trigger threshold value is the magnetic flux density detected by the magnetic sensor 20 at the event occurrence position Pe on the selected detection axis. The calculation unit 36 ​​outputs the calculated trigger threshold value to the output unit 24.

[0052] The output unit 24 detects a predetermined trigger threshold and outputs a trigger signal. The output unit 24 of this example generates a trigger signal when the magnetic flux density of the magnetic field detected by the detection unit 22 exceeds the trigger threshold or is lower than the trigger threshold. The output unit 24 outputs the generated trigger signal to the processing unit 30. The processing unit 30 can perform a predetermined process based on the reception of the trigger signal.

[0053] Figure 2A An example of the arrangement method of the magnetic field generating unit 10 and the magnetic sensor 20 is shown. This figure shows the magnetic field generating unit 10 and the magnetic sensor 20 from the viewpoint of the Y-axis direction.

[0054] The magnetic field generating unit 10 of this example has an N pole and an S pole arranged in the X-axis direction. The X-axis direction is an example of a first direction. However, the magnetic field generating unit 10 is not limited to moving in the X-axis direction, and may also move in the Y-axis direction, the Z-axis direction, or other directions. The magnetic field generating unit 10 of this example has an S pole on the negative side of the X-axis direction than the N pole, but is not limited thereto. The distance between the magnetic field generating unit 10 and the magnetic sensor 20 in the Z-axis direction is not particularly limited as long as it is a distance at which the magnetic sensor 20 can detect the magnetic field of the magnetic field generating unit 10.

[0055] In this example, the shape of the magnet of the magnetic field generating unit 10 is a rectangular parallelepiped, but it can also be other shapes such as a cylinder. The material of the magnet can be any material such as neodymium or ferrite. In one example, when the event detection system 100 is mounted on a curved screen mobile phone, the magnetic field generating unit 10 is mounted on the display side, and the magnetic sensor 20 is mounted on the shell side. The relative position relationship between the magnetic field generating unit 10 and the magnetic sensor 20 changes according to the expansion and contraction of the display.

[0056] Furthermore, if the relative positional relationship between the magnetic field generating unit 10 and the magnetic sensor 20 is to be changed, the magnetic sensor 20 may be moved, or both the magnetic field generating unit 10 and the magnetic sensor 20 may be moved. In one example, when the event detection system 100 is mounted on a roll-up screen mobile phone, the magnetic field generating unit 10 is mounted on the display side, and the magnetic sensor 20 is mounted on the housing side, and the relative positional relationship between the magnetic field generating unit 10 and the magnetic sensor 20 changes according to the expansion and contraction of the display.

[0057] Figure 2B 1 shows an example of a method of arranging the magnetic field generating unit 10 and the magnetic sensor 20. This figure shows the magnetic field generating unit 10 and the magnetic sensor 20 from the viewpoint in the Z-axis direction. That is, the viewpoint in this example represents the viewpoint from the direction relative to Figure 2A The viewpoint after being rotated 90 degrees.

[0058] The magnetic field generating unit 10 moves in a manner that crosses the magnetic sensor 20 on the XY plane. The fact that the magnetic field generating unit 10 crosses the magnetic sensor 20 means that the magnetic field generating unit 10 overlaps a portion of the magnetic sensor 20 on the XY plane. In other words, the magnetic field generating unit 10 can move in a manner that passes over the magnetic sensor 20. In addition, the magnetic field generating unit 10 can also move in a manner that crosses the magnetic sensor 20 on the YZ plane. The magnetic field generating unit 10 crosses the magnetic sensor 20 on a predetermined plane, thereby making it easy to detect a change in magnetic flux density corresponding to the movement of the magnetic field generating unit 10, and making it easy to determine the trigger threshold.

[0059] In addition, the magnetic field generating unit 10 of this example moves parallel to the X-axis direction, but may also move obliquely relative to the X-axis on the XY plane. In this way, the magnetic field generating unit 10 is not limited to being configured to cross the magnetic sensor 20 on the XY plane, which can increase the degree of freedom of housing design.

[0060] In this example, the magnetic field generating unit 10 moves on a straight line, but the present invention is not limited thereto. That is, the magnetic field generating unit 10 may move on a curve or along any other trajectory. The magnetic field generating unit 10 may also rotate on a predetermined circle.

[0061] Figure 2C An example of a configuration method of the magnetic field generating unit 10 and the magnetic sensor 20 is shown. This figure shows the magnetic field generating unit 10 and the magnetic sensor 20 from a viewpoint in the Z-axis direction. This figure is a top view showing a state where the magnetic field generating unit 10 moves on a circumference. Figure 2C In the figure, the magnetic field generating unit 10 moves in a manner that crosses the magnetic sensor 20 on the XY plane. The magnetic field generating unit 10 crossing the magnetic sensor 20 means that the magnetic field generating unit 10 overlaps a portion of the magnetic sensor 20 on the XY plane. In other words, the magnetic field generating unit 10 may move in a manner that passes over the magnetic sensor 20. In addition, the magnetic field generating unit 10 may not pass over the magnetic sensor 20.

[0062] For example, the magnetic field generating unit 10 may move according to the folding of a foldable smartphone (e.g., a foldable phone), and the magnetic field generating unit 10 may also move according to the rotation of the bezel of a smart watch. In the case of a foldable phone, the magnetic field generating unit 10 may be provided on one side, and the magnetic sensor 20 may be provided on the other side, and the magnetic field generating unit 10 may move on a curve according to the opening and closing. In the case of a smart watch, the magnetic sensor 20 may be provided on the main body side, and the magnetic field generating unit 10 may be provided on the bezel side, and the magnetic field generating unit 10 may rotate in a circle according to the rotation drive of the bezel.

[0063] Figure 3A The magnetic field generating unit 10 is shown in a state where it is arranged at the reference position P0. The magnetic field generating unit 10 of this example is arranged so that the boundary between the N pole and the S pole is located above the magnetic sensor 20. In this example, the magnetic flux density Bx in the X-axis direction is greater than the magnetic flux density Bz in the Z-axis direction. However, the magnetic flux density detected by the magnetic sensor 20 at the reference position P0 is not limited thereto.

[0064] Figure 3B FIG. 1 shows a state where the magnetic field generating unit 10 is arranged at the event occurrence position Pe. That is, when the magnetic field generating unit 10 is arranged at the position in this figure, the event detection system 100 performs a predetermined process. Figure 3AThe reference position P0 of is moved toward the positive side of the X-axis direction. Figure 3A Compared with the case where the magnetic field generating unit 10 is present at the reference position P0, the component of the magnetic flux density Bz in the Z-axis direction becomes larger. The relative positional relationship between the magnetic field generating unit 10 and the magnetic sensor 20 and the moving direction of the magnetic field generating unit 10 are not limited to this example, as long as the trigger threshold can be detected by the magnetic sensor 20.

[0065] Figure 3C The magnetic field waveform corresponding to the position of the magnetic field generating unit 10 is shown. The horizontal axis represents the position of the magnetic field generating unit 10 in the X-axis direction, and the vertical axis represents the magnetic flux density Bz in the Z-axis direction. The magnitude of the magnetic flux density Bz measured using the magnetic sensor 20 changes according to the movement of the magnetic field generating unit 10. The magnetic flux density Bz_0 is the magnetic flux density detected by the magnetic sensor 20 when the magnetic field generating unit 10 is configured at the reference position P0. The magnetic flux density Bz_1 is the magnetic flux density detected by the magnetic sensor 20 when the magnetic field generating unit 10 is configured at a position closer to the positive side of the X-axis direction than the reference position P0.

[0066] The magnetic flux density Bthz is the magnetic flux density detected by the magnetic sensor 20 when the magnetic field generating unit 10 is arranged at the event generating position Pe. When the magnetic flux density detected by the magnetic sensor 20 exceeds the magnetic flux density Bthz, the event detection system 100 of this example generates a trigger signal. In addition, in this example, a case where a detection axis of one axis is used for the purpose of explanation is described, but an event can also be detected using detection axes of two or more axes.

[0067] Figure 3D Shown with Figure 3C The magnetic flux density and the change of the trigger signal corresponding to the magnetic field waveform. In this example, from time T0 to time T1, the magnetic field generating unit 10 stops at the reference position P0, and the magnetic flux density Bz does not change.

[0068] At time T1, the magnetic field generating unit 10 starts to move from the reference position P0, and the magnetic flux density gradually increases from Bz_0. At time T2, when the magnetic flux density exceeds the magnetic flux density Bthz, a trigger signal is generated from the magnetic sensor 20. After that, the magnetic field generating unit 10 moves to a position corresponding to the magnetic flux density Bz_1 at time T3 and stops. At time T4, the magnetic field generating unit 10 starts to move toward the reference position P0, and at time T5, when the magnetic flux density is lower than the magnetic flux density Bthz, the generation of the trigger signal is stopped. In this way, the event detection system 100 of this example generates a trigger signal based on the internal threshold judgment of the magnetic sensor 20.

[0069] Next, an example of a threshold determination method using a biaxial magnetic field will be described.

[0070] Figure 4AAn example of a threshold determination method using a two-axis magnetic field is shown. Figure 2A and Figure 2B As shown, the magnetic field generating unit 10 moves in a manner that crosses the magnetic sensor 20 on the XY plane. The event detection system 100 of this example selectively uses the magnetic flux density Bx in the X-axis direction and the magnetic flux density Bz in the Z-axis direction. However, the event generation position Pe corresponds to the vicinity of the inflection point of the magnetic flux density Bz in the Z-axis direction, and the event generation position Pe cannot be correctly detected when the Z-axis is used as the detection axis. Therefore, the event detection system 100 of this example detects the event generation position Pe at the event generation position Pe using the linearly changing magnetic flux density Bx. The event detection system 100 of this example can expand the detectable event area by using the measurement data of more than two axes for threshold judgment.

[0071] In the present embodiment, even when the magnetic field generator 10 moves so as not to cross the magnetic sensor 20 on the XY plane, event detection can be performed.

[0072] Figure 4B An example of a configuration method of the magnetic field generating unit 10 and the magnetic sensor 20 is shown. This figure shows the magnetic field generating unit 10 and the magnetic sensor 20 from the viewpoint of the Z-axis direction. The magnetic field generating unit 10 of this example does not cross the magnetic sensor 20 on the XY plane, but moves to a position offset in the Y-axis direction relative to the magnetic sensor 20. Figure 4B In FIG. 1 , the movement amount y in the Y-axis direction is a positive value. That is, the magnetic field generating unit 10 moves by the amount y in the positive direction of the Y-axis direction, but the present invention is not limited thereto.

[0073] Figure 4C An example of a configuration method of the magnetic field generating unit 10 and the magnetic sensor 20 is shown. This figure shows the magnetic field generating unit 10 and the magnetic sensor 20 from the viewpoint in the Z-axis direction. The magnetic field generating unit 10 of this example does not cross the magnetic sensor 20 in the XY plane, but moves at a position offset in the Y-axis direction relative to the magnetic sensor 20. The magnetic field generating unit 10 can move in the positive direction of the X-axis direction in the XZ plane, and the movement amount y in the Y-axis direction is a negative value. That is, the magnetic field generating unit 10 can move in the negative direction of the Y-axis in the XY plane by the amount y.

[0074] Figure 4D The magnetic field waveform corresponding to the position of the magnetic field generating unit 10 is shown. The horizontal axis represents the position of the magnetic field generating unit 10 in the X-axis direction, and the vertical axis represents the magnetic flux density Bx in the X-axis direction and the magnetic flux density Bz in the Z-axis direction. The magnitudes of the magnetic flux densities Bx and Bz measured by the magnetic sensor 20 change according to the movement of the magnetic field generating unit 10.

[0075] The dotted line indicates Figure 2BThe magnetic field waveform (Bx, Bz) when the magnetic field generating unit 10 moves in a manner that crosses the magnetic sensor 20 is represented by a solid line. Figure 4C The magnetic field waveform (Bxoff, Bzoff) when the magnetic field generating unit 10 moves to a position offset in the Y-axis direction relative to the magnetic sensor 20. Figure 4C In that case, the distance between the magnetic field generating unit 10 and the magnetic sensor 20 is greater than Figure 2B In the case of , the distance between the magnetic field generating unit 10 and the magnetic sensor 20 decreases, and therefore the magnetic flux density detected by the magnetic sensor 20 decreases.

[0076] However, if Figure 4D As shown in FIG. 1 , when the magnetic field generating unit 10 crosses the magnetic sensor 20 on the XY plane and when the position is shifted in the Y-axis direction relative to the magnetic sensor 20, the position of the peak value of the magnetic flux density provided by the magnetic field generating unit 10 in the X-axis direction does not change significantly. Therefore, even when the magnetic field generating unit 10 does not cross the magnetic sensor 20 on the XY plane, the same event detection method as that of the case where the magnetic field generating unit 10 crosses the magnetic sensor 20 can be applied.

[0077] Here, the larger the movement amount y of the magnetic field generating unit 10 in the Y-axis direction, the smaller the intensity of the magnetic flux density detected by the magnetic sensor 20. Although not shown in the figure, Figure 4B The intensity of the magnetic flux density detected by the magnetic sensor 20 is less than that in Figure 4C In this case, the intensity of the magnetic flux density detected by the magnetic sensor 20 is used.

[0078] Thus, the movement amount y of the magnetic field generating unit 10 can be determined by considering the magnetic flux density size that can detect events in a manner that includes the influence of external magnetic field noise, etc. at the position of the magnetic sensor 20. By doing so, the degree of freedom in configuring the magnetic field generating unit 10 and the magnetic sensor 20 is increased, thereby increasing the degree of freedom in the housing design.

[0079] Figure 5 A comparative example of a threshold determination method using a 1-axis magnetic field is shown. In this example, the event generation position Pe corresponds to the vicinity of the inflection point of the magnetic flux density Bz in the Z-axis direction, so it is difficult to correctly determine the position of the magnetic field generating unit near the event generation position Pe. Therefore, in the threshold determination method of the comparative example, an undetectable area Ru where an event cannot be detected will be generated. Therefore, in the method of the comparative example, the event generation position Pe that can be detected will be limited.

[0080] Figure 6An example of a more specific threshold determination method is shown. The event detection system 100 of this example selects and uses a certain detection axis according to the position in the X-axis direction. The solid line in the graph represents a detectable area that can detect the position of the magnetic field generating unit 10. The dotted line in the graph represents an undetectable area where the position of the magnetic field generating unit 10 cannot be detected. In one example, the detectable area is an area that does not have an inflection point of the magnetic flux density and monotonically increases or decreases according to the movement of the magnetic field generating unit 10. The undetectable area is an area where the waveform of the magnetic flux density has an inflection point or an area where the change in the magnetic flux density corresponding to the movement of the magnetic field generating unit 10 is small.

[0081] When the event generation position Pe belongs to the detectable area where the position of the magnetic field generating unit 10 can be detected on the X axis, the selecting unit 34 selects the X axis. On the other hand, when the event generation position Pe does not belong to the detectable area of ​​the X axis but belongs to the detectable area of ​​the Z axis, the selecting unit 34 selects the Z axis. In addition, the selecting unit 34 can select the detection axis based on the reference position P0 and the event generation position Pe.

[0082] The event detection system 100 of this example selects axes in a manner that the axes are divided into five regions, namely, region R1, region R2, region R3, region R1', and region R2'. The selection unit 34 selects the Z axis as the detection axis in the regions R1, region R3, and region R1'. The selection unit 34 selects the X axis as the detection axis in the regions R2 and region R2'.

[0083] Region R1 is the interval between the starting point and boundary 1, and the trigger threshold can be determined using the monotonically decreasing magnetic flux density Bz. Region R2 is the interval between boundary 1 and boundary 2, and the trigger threshold can be determined using the monotonically decreasing magnetic flux density Bx. Region R3 is the interval between boundary 2 and boundary 2', and the trigger threshold can be determined using the monotonically increasing magnetic flux density Bz. Region R2' is the interval between boundary 2' and boundary 1', and the trigger threshold is determined using the monotonically increasing magnetic flux density Bx. Region R1' is the interval between boundary 1' and the end point, and the trigger threshold is determined using the monotonically decreasing magnetic flux density Bz. The method of setting the region is not limited to this.

[0084] As described above, the event detection system 100 sets each area and selects a detection axis so that the magnetic flux density of the selected axis does not have an inflection point. Thus, the event detection system 100 can determine the trigger threshold in a wider range and generate a trigger signal.

[0085] In this embodiment, when multiple trigger thresholds can be set for each detection axis, event detection can be performed when the magnetic field generating unit 10 moves in the positive or negative direction of the X axis. In addition, in this embodiment, when only one trigger threshold can be set for each detection axis, event detection can also be performed.

[0086] As an example, a method of detecting an event when the magnetic field generator 10 moves from the reference position P0 is described. Hereinafter, a method of detecting an event when the magnetic field generator 10 moves in the positive or negative direction of the X axis is described, but the moving direction of the magnetic field generator 10 is not limited thereto.

[0087] Fig. 7A The magnetic field waveform corresponding to the position of the magnetic field generating unit 10 is shown. The horizontal axis represents the position of the magnetic field generating unit 10 in the X-axis direction, and the vertical axis represents the magnetic flux density Bx in the X-axis direction and the magnetic flux density Bz in the Z-axis direction. When the magnetic field generating unit 10 moves in the positive direction or negative direction of the X-axis near the reference position P0, when neither Bx nor Bz includes an inflection point, event detection can be performed when the magnetic field generating unit 10 moves ±1 mm from the reference position P0.

[0088] For example, in Fig. 7A In the figure, when the reference position P0 is 2 mm, the trigger threshold value corresponding to the event generation position Pe+ when moving toward the positive side is Bx, and the trigger threshold value corresponding to the event generation position Pe- when moving toward the negative side is Bz, to perform event detection separately. Thus, even when only one trigger threshold value can be set for each detection axis, event detection can be performed.

[0089] However, for example, Fig. 7A In the case where the reference position P0 is 0 mm, the change of Bx is small around the reference position P0, so event detection using Bx cannot be performed. Even in such a case, if the magnetic sensor 20 can calculate the square root of the sum of squares of the magnetic flux density Bsum, event detection can be performed. That is, event detection can be performed by calculating the trigger threshold corresponding to the event generation position Pe using the square root of the sum of squares Bsum. The square root of the sum of squares of the magnetic flux density Bsum can be expressed by the formula shown in the following formula 1.

[0090]

Formula 1

[0091]

[0092] Figure 7B The magnetic field waveform corresponding to the position of the magnetic field generating unit 10 is shown. The horizontal axis represents the position of the magnetic field generating unit 10 in the X-axis direction, and the vertical axis represents the magnetic flux density Bx in the X-axis direction, the magnetic flux density Bz in the Z-axis direction, and the square root of the sum of the squares of the magnetic flux density Bsum. For example, when the reference position P0 is 0 mm, by using Bsum in a bilaterally symmetrical shape, event detection can be performed when the reference position P0 moves by ±1 mm.

[0093] Figure 7CMagnetic field waveforms corresponding to the positions of the magnetic field generating unit 10 are shown. Figure 7C In the reference position P0 and Figure 7B The same is 0mm. Figure 7C In the example, Bz is used as the trigger threshold corresponding to the event position Pe+ when the event moves to the positive side, and Bsum is used as the trigger threshold corresponding to the event position Pe- when the event moves to the negative side, to respectively detect events. Thus, even when only one trigger threshold can be set for each detection axis, event detection can be performed.

[0094] Fig.7D The figures respectively show the case where the reference position P0 is 1 mm. Fig.7D In the process, Bsum is used as the trigger threshold value corresponding to the event occurrence position Pe+ when the event moves to the positive side, and Bz is used as the trigger threshold value corresponding to the event occurrence position Pe- when the event moves to the negative side, and event detection is performed separately. Thus, even when only one trigger threshold value can be set for each detection axis, event detection can be performed.

[0095] Fig. 7E This is a diagram showing the case where the reference position P0 is -1 mm. Fig. 7E In the process, event detection is performed separately by using Bz as the trigger threshold value corresponding to the event occurrence position Pe+ when moving to the positive side, and using Bsum as the trigger threshold value corresponding to the event occurrence position Pe- when moving to the negative side. Thus, event detection can be performed even when only one trigger threshold value can be set for each detection axis.

[0096] As described above, the event detection system 100 can detect events in two directions by using the square root of the sum of squares of magnetic flux density Bsum. Thus, even when only one trigger threshold can be set for the selected detection axis, the event detection system 100 can determine the trigger threshold and generate a trigger signal.

[0097] Furthermore, in the present embodiment, when only one trigger threshold can be set for each detection axis, even when the magnetic sensor 20 cannot calculate the square root Bsum of the sum of squares of magnetic flux density, event detection can be performed.

[0098] Fig. 8A Shown as Figure 4CAs shown in FIG. 1 , the magnetic field waveform corresponding to the position of the magnetic field generating unit 10 when the magnetic field generating unit 10 does not cross the magnetic sensor 20. The horizontal axis represents the position of the magnetic field generating unit 10 in the X-axis direction, and the vertical axis represents the magnetic flux density Bx in the X-axis direction, the magnetic flux density By in the Y-axis direction, and the magnetic flux density Bz in the Z-axis direction. When the magnetic field generating unit 10 moves in the positive direction or negative direction of the X-axis near the reference position P0, when neither Bx nor Bz includes an inflection point, event detection can be performed when the magnetic field generating unit 10 moves ±1 mm from the reference position P0.

[0099] For example, in Fig. 8A In the figure, when the reference position P0 is 2 mm, the trigger threshold value corresponding to the event generation position Pe+ when moving toward the positive side is Bx, and the trigger threshold value corresponding to the event generation position Pe- when moving toward the negative side is Bz, to perform event detection separately. Thus, even when only one trigger threshold value can be set for each detection axis, event detection can be performed.

[0100] However, for example, Fig. 8A In the case where the reference position P0 is 0 mm, the change in Bx is small around the reference position P0, so event detection using Bx cannot be performed. Even in such a case, event detection can be performed by selecting the Y axis as the detection axis and using By.

[0101] Figure 8B : is a diagram showing the case where the reference position P0 is 0 mm. In this embodiment, the following case is shown: Bz is used as the trigger threshold corresponding to the event generation position Pe+ when the movement is made to the positive side, and By is used as the trigger threshold corresponding to the event generation position Pe- when the movement is made to the negative side, and event detection is performed separately. Thus, even when only one trigger threshold can be set for each detection axis, event detection can be performed, but it is not limited to this. That is, By is used as the trigger threshold corresponding to the event generation position Pe+ when the movement is made to the positive side, and Bz is used as the trigger threshold corresponding to the event generation position Pe- when the movement is made to the negative side, and event detection is performed separately.

[0102] Figure 8C: is a diagram showing the case where the reference position P0 is 1 mm. In this embodiment, the following case is shown: Bz is used as the trigger threshold corresponding to the event generation position Pe+ when the movement is made to the positive side, and By is used as the trigger threshold corresponding to the event generation position Pe- when the movement is made to the negative side, and event detection is performed separately. Thus, even when only one trigger threshold can be set for each detection axis, event detection can be performed, but it is not limited to this. That is, By is used as the trigger threshold corresponding to the event generation position Pe+ when the movement is made to the positive side, and Bz is used as the trigger threshold corresponding to the event generation position Pe- when the movement is made to the negative side, and event detection is performed separately.

[0103] Fig.8D : is a diagram showing the case where the reference position P0 is -1 mm. In this embodiment, the following case is shown: Bz is used as the trigger threshold corresponding to the event generation position Pe+ when the movement is made to the positive side, and By is used as the trigger threshold corresponding to the event generation position Pe- when the movement is made to the negative side, and event detection is performed separately. Thus, even when only one trigger threshold can be set for each detection axis, event detection can be performed, but it is not limited to this. That is, By is used as the trigger threshold corresponding to the event generation position Pe+ when the movement is made to the positive side, and Bz is used as the trigger threshold corresponding to the event generation position Pe- when the movement is made to the negative side, and event detection is performed separately.

[0104] Fig. 9 An example of the operation flow of the event detection system 100 is shown. In this example, a method is shown in which, after the processing unit 30 shifts to the standby state, a predetermined event is detected and a trigger signal for activating the processing unit 30 is generated.

[0105] It is possible that steps S300 to S314 are performed by the processing unit 30, and steps S200 to S206 are performed by the magnetic sensor 20. In step S300, the processing unit 30 is set to an activated state. In step S302, in order to obtain the measurement data of the reference position P0 of the magnetic field generating unit 10, the magnetic sensor 20 is requested to read the measurement data. Thus, the processing unit 30 obtains the measurement data (Bx, By, Bz) at the reference position P0 from the magnetic sensor 20. The reference position P0 of the magnetic field generating unit 10 is not particularly limited.

[0106] In step S304, the processing unit 30 determines the region of the reference position P0 of the magnetic field generator 10 based on the acquired measurement data. For example, the processing unit 30 calculates the reference position P0 of the magnetic field generator 10 using a pre-created data table or function fitting.

[0107] In step S306, the processing unit 30 determines the area of ​​the event generation position Pe. The processing unit 30 may also store a preset event generation position Pe. The processing unit 30 may also determine the area of ​​the event generation position Pe based on the measurement data when the magnetic field generating unit 10 is located at the event generation position Pe. In step S308, the processing unit 30 calculates the trigger threshold based on the event generation position Pe. The processing unit 30 may calculate the trigger threshold using a pre-created data table or function fitting.

[0108] In step S310, the processing unit 30 writes the calculated trigger threshold to the magnetic sensor 20. Thus, in step S202, the detection axis and trigger threshold to be used are set for the magnetic sensor 20. It can be that the magnetic sensor 20 does not use the axis that is not needed in the determination of the trigger threshold and does not detect the magnetic flux density. The magnetic sensor 20 measures the magnetic field, and when the magnetic flux density of the magnetic field exceeds the set trigger threshold or is lower than the set trigger threshold, the trigger signal is output to the processing unit 30 (step S204, step S206). Then, the processing unit 30 becomes the start state due to receiving the trigger signal (step S314).

[0109] Fig.10 An example of the configuration of the event detection system 100 is shown. Figure 2A The embodiment of the present invention is different in that the event detection system 100 of the present embodiment includes a plurality of magnetic sensors 20. The event detection system 100 of the present embodiment includes two magnetic sensors 20, namely, a magnetic sensor 20a and a magnetic sensor 20b.

[0110] The magnetic sensor 20a and the magnetic sensor 20b are arranged in the X-axis direction which is the moving direction of the magnetic field generating unit 10. The magnetic sensor 20a and the magnetic sensor 20b may be magnetic sensors of the same type or magnetic sensors of different types. The magnetic sensor 20b may overlap with the detectable event region of the magnetic sensor 20a or may not overlap with the detectable event region of the magnetic sensor 20a.

[0111] The event detection system 100 can further expand the detectable event area by providing a plurality of magnetic sensors 20. The processing unit 30 can select the magnetic sensor 20 to be used by the same process as the process of determining the detection axis when there is one magnetic sensor 20, and determine the detection axis from the selected magnetic sensor 20. Thus, the event detection system 100 can use the best detection axis in the best magnetic sensor 20 according to the event occurrence position Pe.

[0112] Fig.11An example of a computer 2200 that can implement multiple embodiments of the present invention in whole or in part is shown. The program installed in the computer 2200 can cause the computer 2200 to function as an operation associated with the device involved in the embodiment of the present invention or one or more parts of the device, or can cause the computer 2200 to perform the operation or the one or more parts, and / or can cause the computer 2200 to perform a process involved in the embodiment of the present invention or a stage of the process. Such a program can be executed by the CPU 2212 to cause the computer 2200 to perform specific operations associated with some or all blocks in the flowcharts and block diagrams described in this specification.

[0113] The computer 2200 of the present embodiment includes a CPU 2212, a RAM 2214, a graphic controller 2216, and a display device 2218, which are connected to each other through a main controller 2210. The computer 2200 also includes input / output units such as a communication interface (I / F) 2222, a hard disk drive 2224, a DVD-ROM drive 2226, and an IC card drive, which are connected to the main controller 2210 via an input / output (I / O) controller 2220. The computer also includes conventional 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 (I / O) chip 2240.

[0114] The CPU 2212 controls each unit by operating according to the program stored in the ROM 2230 and the RAM 2214. The graphic controller 2216 acquires image data generated by the CPU 2212 in a frame buffer or the like provided in the RAM 2214 or in the RAM 2214 itself, and displays the image data on the display device 2218.

[0115] The communication 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.

[0116] A boot program or the like executed by the computer 2200 at the time of activation and / or a program depending on the hardware of the computer 2200 is stored in the ROM 2230. The input / output chip 2240 can 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, and the like.

[0117] The program is provided by a computer-readable medium such as DVD-ROM 2201 or an IC card. The program is read from the computer-readable medium, installed in the hard disk drive 2224, RAM 2214 or ROM 2230, which is also an example of a computer-readable medium, and executed by the CPU 2212. After the information processing described in these programs is read by the computer 2200, the program and the various types of hardware resources described above are coordinated. The device or method can be constructed by implementing the operation or processing of information according to the use of the computer 2200.

[0118] For example, in the case where the computer 2200 performs communication with an external device, the CPU 2212 can execute the communication program loaded in 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 the transmission data stored in the transmission buffer processing area provided in the recording medium such as the RAM 2214, the hard disk drive 2224, the DVD-ROM 2201 or the IC card, and transmits the read transmission data to the network, or writes the reception data received from the network to the reception buffer processing area provided on the recording medium, etc.

[0119] In addition, the CPU 2212 can read all or a necessary part of a file or database stored in an external recording medium such as the hard disk drive 2224, the DVD-ROM drive 2226 (DVD-ROM 2201), an IC card, etc. into the RAM 2214, and perform various types of processing on the data on the RAM 2214. The CPU 2212 then writes the processed data back to the external recording medium.

[0120] Various types of information such as various types of programs, data, tables, and databases can be stored in the recording medium and subjected to information processing. The CPU 2212 can perform various types of processing described in various places of the present disclosure, including various types of operations specified by the command sequence of the program, information processing, conditional judgment, conditional branching, unconditional branching, information retrieval / replacement, etc., for the data read from the RAM 2214, and write the results back to the RAM 2214. In addition, the CPU 2212 can retrieve information in files, databases, etc. in the recording medium. For example, when multiple entries each having an attribute value of a first attribute associated with an attribute value of a second attribute are stored in the recording medium, the CPU 2212 can retrieve an entry that is consistent with the condition specifying the attribute value of the first attribute from 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 meets the predetermined condition.

[0121] The program or software module described above may be stored in a computer-readable medium on or near the computer 2200. In addition, 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 be used as a computer-readable medium, thereby providing the program to the computer 2200 via the network.

[0122] The present invention has been described above using the embodiments, but the protection scope of the present invention is not limited to the scope described in the above embodiments. It is obvious to those skilled in the art that various changes or improvements can be made to the above embodiments. According to the description of the claims, the methods obtained by applying such changes or improvements can also be included in the protection scope of the present invention.

[0123] It should be noted that the execution order of each process such as actions, processes, steps and stages in the devices, systems, programs and methods shown in the claims, specifications and drawings can be implemented in any order unless it is specifically stated as "before...", "prior to...", etc., and as long as the output of the previous process is not used in the subsequent process. Although the action flow in the claims, specifications and drawings is described using "first", "next", etc. for convenience, it does not mean that it must be implemented in this order.

[0124] Description of Reference Numerals

[0125] 10: magnetic field generating unit; 20: magnetic sensor; 22: detecting unit; 24: output unit; 30: processing unit; 32: acquiring unit; 34: selecting unit; 36: calculating unit; 100: event detection system; 2200: computer; 2201: DVD-ROM; 2210: main controller; 2212: CPU; 2214: RAM; 2216: graphic controller; 2218: display device; 2220: input / output controller; 2222: communication interface; 2224: hard disk drive; 2226: DVD-ROM drive; 2230: ROM; 2240: input / output chip; 2242: keyboard.

Claims

1. An event detection method, comprising: detecting an event corresponding to a position of a magnetic field generating unit by detecting magnetic fields of two or more detection axes predetermined by the magnetic field generating unit using a multi-axis magnetic sensor, the event detection method comprising the following stages: acquiring a location where an event occurs based on the magnetic field detected by the multi-axis magnetic sensor; Based on the event occurrence position, selecting a detection axis for detecting the event from the two or more detection axes; Calculating a trigger threshold corresponding to the event occurrence position on the selected detection axis; as well as A trigger signal is acquired, indicating that the magnetic flux density of the selected detection axis detected by the multi-axis magnetic sensor and the trigger threshold satisfy a predetermined condition.

2. The event detection method according to claim 1, characterized in that: It also includes the following stages: moving the magnetic field generating unit in a predetermined first direction; and A first axis parallel to the first direction or a second axis orthogonal to the first axis is selected from the two or more detection axes as the detection axis.

3. The event detection method according to claim 2, characterized in that: The step of moving the magnetic field generating unit in the predetermined first direction includes the step of moving the magnetic field generating unit on the first axis or the second axis so as to pass over the multi-axis magnetic sensor.

4. The event detection method according to claim 3, characterized in that: The step of moving the magnetic field generating unit in a predetermined first direction includes the following steps: moving the magnetic field generating unit to a position offset in the direction of the third axis relative to the multi-axis magnetic sensor on a plane formed by the first axis and a third axis, the third axis being orthogonal to the first axis and the second axis, The amount of movement of the magnetic field generating unit in the direction of the third axis is determined based on a magnitude of magnetic flux density that enables event detection such that the magnetic flux density at the position of the multi-axis magnetic sensor includes the influence of external magnetic field noise.

5. The event detection method according to any one of claims 2 to 4, characterized in that: The stage of selecting the detection axis from the two or more detection axes includes the following stages: When the event occurrence position belongs to a detectable area on the first axis, the first axis is selected from the two or more detection axes, and the detectable area is an area where the position of the magnetic field generating unit can be detected. When the event occurrence position does not belong to the detectable area of ​​the first axis but belongs to the detectable area of ​​the second axis, the second axis is selected from the two or more detection axes.

6. The event detection method according to claim 5, characterized in that: The stage of calculating the trigger threshold comprises the following stages: calculating the magnetic flux density detected by the multi-axis magnetic sensor at the event generation position on the selected detection axis as the trigger threshold, The stage of acquiring the trigger signal includes the following stage: acquiring a trigger signal indicating that the magnetic flux density of the selected detection axis detected by the multi-axis magnetic sensor exceeds the trigger threshold or is lower than the trigger threshold.

7. The event detection method according to claim 6, characterized in that: The magnetic flux density in the detectable area does not have an inflection point.

8. The event detection method according to any one of claims 1 to 4, 6 and 7, characterized in that: It also includes the following stages: acquiring a reference position of the magnetic field generating unit; and The detection axis is selected from the two or more detection axes based on the reference position and the event occurrence position.

9. The event detection method according to any one of claims 1 to 4, 6 and 7, characterized in that: It also includes the following stages: calculating a square root of a sum of squares of magnetic fields detected by the multi-axis magnetic sensor; as well as The square root of the square sum is used to calculate a trigger threshold corresponding to the event generation location.

10. An event detection system comprising: a magnetic field generating unit that generates a predetermined magnetic field; a multi-axis magnetic sensor for detecting magnetic fields of two or more detection axes generated by the magnetic field generating unit; and a processing unit, which is used to process the signal detected by the multi-axis magnetic sensor, in, The processing unit comprises: an acquisition unit that acquires an event occurrence position based on the magnetic field detected by the multi-axis magnetic sensor; a selection unit that selects a detection axis for detecting an event from among the two or more detection axes based on the event occurrence position; as well as a calculation unit for calculating a trigger threshold corresponding to a position where the event occurs on the selected detection axis; The event detection system further includes an output unit that outputs a trigger signal indicating that the magnetic flux density of the selected detection axis detected by the multi-axis magnetic sensor and the trigger threshold satisfy a predetermined condition.

11. The event detection system according to claim 10, characterized in that: The selection unit selects, from among the two or more detection axes, a first axis parallel to a predetermined first direction in which the magnetic field generating unit moves, or a second axis orthogonal to the first axis as the detection axis.

12. The event detection system according to claim 11, characterized in that: The magnetic field generating unit moves on the first axis or the second axis so as to pass over the multi-axis magnetic sensor.

13. The event detection system according to claim 12, characterized in that: The magnetic field generating unit moves on a plane formed by the first axis and a third axis to a position offset relative to the multi-axis magnetic sensor in a direction of the third axis, the third axis being orthogonal to the first axis and the second axis, The amount of movement of the magnetic field generating unit in the direction of the third axis is determined based on a magnitude of magnetic flux density that enables event detection such that the magnetic flux density at the position of the multi-axis magnetic sensor includes the influence of external magnetic field noise.

14. The event detection system according to any one of claims 11 to 13, characterized in that: When the event occurrence position belongs to a detectable area on the first axis, the selection unit selects the first axis from the two or more detection axes, and the detectable area is an area where the position of the magnetic field generating unit can be detected. When the event occurrence position does not belong to the detectable area of ​​the first axis but belongs to the detectable area of ​​the second axis, the selection unit selects the second axis from the two or more detection axes.

15. The event detection system according to claim 14, characterized in that: The calculation unit calculates the magnetic flux density on the selected detection axis detected by the multi-axis magnetic sensor at the event occurrence position as the trigger threshold, The output unit outputs a trigger signal indicating that the magnetic flux density of the selected detection axis detected by the multi-axis magnetic sensor exceeds the trigger threshold or falls below the trigger threshold.

16. The event detection system according to claim 15, characterized in that: The magnetic flux density in the detectable area does not have an inflection point.

17. The event detection system according to any one of claims 10 to 13, 15 and 16, characterized in that: The processing unit acquires a reference position of the magnetic field generating unit, and selects the detection axis from the two or more detection axes based on the reference position and the event occurrence position.

18. The event detection system according to claim 11, characterized in that: The magnetic field generating unit has an N pole and an S pole arranged in the first direction.

19. The event detection system according to claim 11 or 12, characterized in that: A plurality of multi-axis magnetic sensors are provided which are arranged in the first direction.

20. The event detection system according to any one of claims 10 to 13, 15, 16, and 18, characterized in that: The processing unit calculates a square root of a sum of squares of magnetic fields detected by the multi-axis magnetic sensor, and calculates a trigger threshold corresponding to a location where the event occurs using the square root of the sum of squares.

21. The event detection system according to claim 10, characterized in that: The event detection system is mounted on a mobile terminal with a retractable display. The relative positional relationship between the magnetic field generating unit and the multi-axis magnetic sensor changes according to the expansion and contraction of the display. The output unit outputs a trigger signal indicating that the magnetic flux density of the selected detection axis detected by the multi-axis magnetic sensor and the trigger threshold satisfy the condition that the display is extended to a predetermined position, so as to switch the display of the display or switch the mobile terminal from a standby state to a startup state.

22. A computer program product comprising a program for causing a computer to execute the event detection method according to any one of claims 1 to 9.

23. A computer-readable medium storing a program for causing a computer to execute the event detection method according to any one of claims 1 to 9.

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