KR20200126315A - Method of measuring angle between two bodies of foldable device and apparatus therefor - Google Patents

Abstract

Disclosed are a method for measuring an angle of a foldable device and a device therefor. A first magnetic sensor unit installed on a first body of the foldable device detects the magnitude of an external magnetic field applied to itself, and generates first azimuth information representing a direction in which the first body is directed. A second magnetic sensor unit installed on a second body of the foldable device, which is foldably coupled to the first body detects the magnitude of an external magnetic field applied to itself to generate second azimuth information representing a direction in which the second body is directed. A control unit calculates an angle between the first body and the second body by using the first azimuth information and the second azimuth information. The first and second magnetic sensor units may be implemented as a magnetic fluxgate sensor unit, respectively. The size of an origin offset which each magnetic fluxgate sensor unit has in an initial state can be obtained in advance and applied to the calculation of an interposition angle.

Description

Method for measuring the angle between two bodies of a foldable device and a device therefor {METHOD OF MEASURING ANGLE BETWEEN TWO BODIES OF FOLDABLE DEVICE AND APPARATUS THEREFOR}

The present invention relates to a method and apparatus for measuring an angle between a foldable device, and more particularly, to two bodies of a foldable device capable of measuring the angle between the two bodies folded to be folded in real time when the angle between them changes. It relates to a method for measuring the angle between the minor and an apparatus therefor.

A variety of devices and devices are used in which the two components perform a relative rotational motion with respect to one central axis so that the angle between the two components can be changed. That is, one side of each of the two components is rotatably coupled through the coupling shaft, and may be folded or unfolded around the coupling shaft as necessary. Examples of such a foldable structure include, for example, a robot device including first and second robot arm members axially coupled so that the angle between each other can be variable, and the door frame and the door frame can be rotatably coupled to the door frame to be opened and closed. An example is a revolving door device including a door that is in place. Typical examples of electronic devices having a foldable structure include a notebook computer and a foldable tablet computer. Recently, a folder in which two bodies are combined in a foldable structure through a coupling shaft and employs a flexible, bendable, or rollable display (hereinafter collectively referred to as'foldable display'). The commercial launch of the mobile phone is also scheduled. In the future, there will be a wide variety of applications that apply a foldable display. For example, an electronic device with a foldable display employs a plurality of displays to independently output a plurality of screens or to divide and output one screen, and the two components of the foldable device can be folded with each other. It can be combined in a hinge structure, for example.

In an apparatus or device having a foldable structure, a predetermined follow-up action (required operation, processing, control, etc.) may be taken depending on the size of the angle between the two components. For example, when the closed door rotates and the angle between the door frame becomes more than a predetermined angle, it is determined that the door is open, and necessary actions (eg, an alarm notifying that there is an unwanted door opening, etc.) can be taken. For example, according to the size of the angle between the first and second robot arm members coupled to the axis, a predetermined operation of the robot device may be performed or an action may be taken of providing the angle data to the outside. In addition, for example, a function of outputting various user interfaces (UI) may be required according to an angle between two components of the foldable electronic device (ie, an opening angle or a folding angle). For example, in the case of a foldable smartphone, the display portion provided on the two body portions may have different usage types when the two body portions are folded and in an open state. That is, when the display unit is folded, the display unit is divided into two display areas and used as an independent display screen of each body unit, and when the display unit is opened, the display unit can function as one screen.

In such a variety of foldable devices, there are many cases in which some decision or processing needs to be made according to the size of the angle between the two components. For example, the UI can be variably applied according to the opening angle of the two body parts of the foldable smartphone. Therefore, there is a need for a technology capable of accurately measuring the angle between two components forming a foldable structure in real time.

The portable foldable electronic device may change its posture or direction from time to time during use, and the angle between the two components may also change during the change of posture or direction. Even in such a situation, a technology that can accurately measure the angle between two components in real time is required.

Korean Patent Publication No. 10-2017-0031525 discloses a technology for measuring the angle between two displays using two acceleration sensors or one acceleration sensor and one angular velocity sensor. However, this technology has the following technical limitations. In the case of using the acceleration sensor, when the entire or part of the foldable device as well as the body part equipped with the acceleration sensor performs acceleration motion, the acceleration sensor does not accurately recognize the direction of gravitational acceleration, causing an error in measuring the rotation angle. I can. Using one acceleration sensor and one angular velocity sensor, the angle between the two displays can be measured when the power is on. However, when the power supply to the angular velocity sensor is turned off and then turned on again, the angular velocity sensor cannot measure the angle between the two components at the time when the power supply is turned on. In a state where it is impossible to measure the angle between the two components formed at the present time, it is not possible to accurately measure the angle between the two components simply by calculating the displacement of the rotation angle of the component with the acceleration sensor installed.

The present invention was invented to solve the above-described problem, and an object according to an aspect of the present invention is to use a minimum magnetic sensor regardless of acceleration motion and power on/off of all or part of the foldable device. It is to provide a method and apparatus for accurately measuring the angle between two body parts of a device in real time.

The problem to be solved by the present invention is not limited to the above-described problems, and may be variously expanded without departing from the spirit and scope of the present invention.

An apparatus for measuring an angle between two body parts of a foldable device according to embodiments for realizing an object of the present invention may include a first magnetic sensor unit, a second magnetic sensor unit, and a control unit. The first magnetic sensor unit is installed in the first body portion of the foldable device in which the first body portion and the second body portion are foldably coupled via a folding axis to detect the magnitude of an external magnetic field applied to the first body portion and the first body portion. It is configured to detect first orientation information representing a direction in which the body portion is directed. The second magnetic sensor unit is installed on the second body and is configured to detect a magnitude of an external magnetic field applied to the second body to detect second orientation information representing a direction in which the second body is directed. The control unit is configured to receive the first orientation information and the second orientation information from the first and second magnetic sensor parts and calculate an angle between the first body part and the second body part around the folding axis. do.

In example embodiments, in a three-dimensional coordinate system having a point on the folding axis as an origin, the first orientation information is determined by the magnitude of an external magnetic field component in at least the first direction and the second direction from the origin. Information that can be mapped to a first azimuth vector connecting a determined first point, and the second azimuth information is a second point determined by the magnitude of external magnetic field components in the third and fourth directions from the origin It may be information that can be mapped to a second orientation vector connected to. The first direction is an arbitrary direction substantially parallel to the plane of the first body part, the second direction is a substantially normal direction to the plane of the first body part, and the third direction is the plane of the second body part It is an arbitrary direction substantially parallel, and the fourth direction may be a direction substantially normal to a plane of the second body part.

In example embodiments, the control unit obtains each of the first orientation vector mapped by the first orientation information and the second orientation vector mapped by the second orientation information, and the first orientation vector and It may be configured to calculate an angle between the second orientation vectors.

In example embodiments, the first magnetic sensor unit includes a first fluxgate device configured to detect an external magnetic field component in at least a first direction, a second fluxgate device configured to detect an external organ field component in a second direction, And at least the first and second driving currents required for driving the first and second fluxgate devices are applied, respectively, and magnetic fields and external application by the first and second driving currents from the first and second fluxgate devices are applied. It may be a first magnetic fluxgate sensor unit including a first driving/detecting unit configured to detect the first orientation information by receiving first and second pick-up voltages induced by a magnetic field, respectively. The second magnetic sensor unit includes a third fluxgate device configured to detect an external magnetic field component in at least a third direction, a fourth fluxgate device configured to detect an external magnetic field component in a fourth direction, and at least the third and fourth fluxes. The third and fourth driving currents required for driving the gate element are applied, respectively, and the third and fourth magnetic fields induced by the third and fourth driving currents and the externally applied magnetic fields are induced from the third and fourth fluxgate elements. 4 It may be a second magnetic fluxgate sensor unit including a second driving/detecting unit configured to receive each pickup voltage and detect the second orientation information. The first direction is an arbitrary direction substantially parallel to the plane of the first body part, the second direction is a substantially normal direction to the plane of the first body part, and the third direction is the plane of the second body part It is an arbitrary direction substantially parallel, and the fourth direction may be a direction substantially normal to a plane of the second body part.

In example embodiments, each of the first to fourth fluxgate elements may be formed in a structure in which a driving coil and a pickup coil are wound around a magnetic material. Each of the first driving/detecting units is configured by the magnetization reversal characteristics of the magnetic bodies of the first and second fluxgate devices in each cycle while applying an AC driving current to the driving coils of the first and second fluxgate devices. The first azimuth information is respectively calculated using the degree to which each voltage peak of the generated first and second pickup voltages is shifted by the strength of an external magnetic field applied to the pickup coils of the first and second fluxgate elements, respectively. Can be configured to produce. The second driving/detecting unit is configured for each period while applying an AC driving current to the driving coils of the third and fourth fluxgate devices, respectively, by magnetization reversal characteristics of the magnetic bodies of the third and fourth fluxgate devices. The second azimuth information is respectively calculated using a degree in which each voltage peak of the generated third and fourth pickup voltages is shifted by the strength of an external magnetic field applied to the pickup coils of the first and second fluxgate elements, respectively. Can be configured to produce.

In example embodiments, the apparatus for measuring an angle between two body parts of the foldable device is provided on the first body part and the second body part, respectively, and configured to provide an interface function with a user, and It may further include a second interface unit. The control unit may be configured to control the first and second interface units to operate as one integrated interface unit or as separate independent interface units according to the calculated size of the interval.

In example embodiments, each of the first and second magnetic fluxgate sensor units stores a pre-obtained origin offset size of each fluxgate element, and each flux stored when the first and second orientation information is detected. It may be configured to apply an origin offset size of the gate element, respectively. Here, the size of the origin offset of each fluxgate element is the time difference from the start of one period of the pickup voltage in the pickup voltage profile of the corresponding fluxgate element to the occurrence of the voltage peak when no external magnetic field is applied or equivalent thereto. It may be the strength of the external magnetic field.

In example embodiments, the control unit stores a pre-obtained origin offset size of each of the fluxgate elements of the first and second magnetic fluxgate sensor units, and the first body portion and the second body portion When calculating the intervening angle of the liver, it may be configured to apply an origin offset size for each fluxgate element to the first orientation information and the second orientation information provided from the first and second magnetic fluxgate sensor units, respectively. Here, the size of the origin offset of each fluxgate element is the time difference from the start of one period of the pickup voltage in the pickup voltage profile of the corresponding fluxgate element to the occurrence of the voltage peak when no external magnetic field is applied or equivalent thereto. It may be the strength of the external magnetic field.

In exemplary embodiments, the foldable device may reversibly move from a state in which the first body portion and the second body portion are combined with a hinge axis and folded to overlap each other to an unfolded state to form the same plane, It may be a foldable communication device further comprising a display unit disposed on one surface of the first and second members.

On the other hand, the method for measuring the angle between two body parts of a foldable device according to embodiments for realizing one object of the present invention is an external magnetic field applied to the first magnetic sensor unit installed on the first body part of the foldable device A second magnetic sensor installed on the second body of the foldable device, which detects the size of and generates first orientation information representing the direction in which the first body is directed, and is foldably coupled with the first body First and second orientation information generating steps of generating second orientation information representing a direction in which the second body portion is directed by detecting the magnitude of the external magnetic field applied to the body; And the first body part around a folding axis between the first body part and the second body part by using the first orientation information and the second orientation information provided from the first and second magnetic sensor parts. And a step of calculating a gap angle of calculating a gap between the and the second body part.

In example embodiments, the method of measuring an angle between two body portions of the foldable device further includes the step of controlling or processing a predetermined operation of the foldable device, which is predetermined according to the calculated size of the angle between the foldable device. Can include.

In example embodiments, in a three-dimensional coordinate system having a point on the folding axis as an origin, the first orientation information is determined by the magnitude of an external magnetic field component in at least the first direction and the second direction from the origin. It may be information that can be mapped to a first orientation vector connecting the determined first point. The second orientation information may be information that can be mapped to a second orientation vector connecting a second point determined by the magnitude of an external magnetic field component in the third direction and the fourth direction from the origin. The first direction is an arbitrary direction substantially parallel to the plane of the first body part, the second direction is a substantially normal direction to the plane of the first body part, and the third direction is the plane of the second body part It is an arbitrary direction substantially parallel, and the fourth direction may be a direction substantially normal to a plane of the second body part.

In example embodiments, the first magnetic sensor unit comprises at least a first fluxgate element configured to detect an external magnetic field component in the first direction, and a second fluxgate configured to detect an external organ field component in the second direction. It may be a device and a first magnetic fluxgate sensor unit including a first driving/detecting unit. The second magnetic sensor unit at least the sensor comprises at least a third fluxgate element configured to detect an external magnetic field component in the third direction, a fourth fluxgate element configured to detect an external magnetic field component in the fourth direction, and a second drive It may be a second magnetic fluxgate sensor unit including a /detector unit. The step of generating the first orientation information is performed by the first driving/detecting unit and, under a condition in which an external magnetic field is applied, at least while passing an AC driving current to the driving coils of the first and second fluxgate elements, respectively. Detecting first and second pick-up voltages respectively induced in pick-up coils of the first and second fluxgate elements; Detecting a time point of occurrence of a first voltage peak from the profile of the first pick-up voltage and detecting a point of occurrence of a second voltage peak from the profile of the second pick-up voltage every period; And a first shift amount at the time of occurrence of the first voltage peak and a second amount of shift at the time of occurrence of the second voltage peak compared to a time point of occurrence of the voltage peak when the external magnetic field is not applied, as the first orientation information. It may include the step of outputting. The step of generating the second orientation information is performed by the second driving/detecting unit and, under a condition in which an external magnetic field is applied, at least while passing an AC driving current to the driving coils of the third and fourth fluxgate elements, respectively. Detecting third and fourth pick-up voltages respectively induced in pick-up coils of the third and fourth fluxgate elements; Detecting a point of occurrence of a third voltage peak from the profile of the third pickup voltage and detecting a point of occurrence of a fourth voltage peak from the profile of the fourth pickup voltage every period; And a third shift amount at the time when the third voltage peak occurs and a fourth shift amount at the time when the fourth voltage peak occurs compared to when the voltage peak occurs when the external magnetic field is not applied, as the second orientation information. It may include the step of outputting.

In example embodiments, the k-th voltage peak generation point (where k=1, 2, 3, 4) is a value representing the magnitudes of voltages in an initial predetermined period in the k-th pickup voltage profile of the current period. Is calculated as a base voltage, a k-th reference voltage obtained by adding a gap voltage of a predetermined size to the base voltage is calculated, and a voltage value in the profile of the k-th pickup voltage of the current period is equal to the magnitude of the k-th reference voltage. The time point may be determined by a method of determining the time when the kth voltage peak occurs.

In example embodiments, the method of measuring an angle between two body parts of the foldable device includes performing calibration for correcting a measurement error of each of the first and second magnetic fluxgate sensor units in an initial state. It may further include.

In example embodiments, the performing of the calibration includes calculating the first and second origin offset sizes of the first and second fluxgate elements of the first magnetic fluxgate sensor and storing them in a data storage unit. Step to do; Calculating third and fourth origin offset sizes of the third and fourth fluxgate elements of the second magnetic fluxgate sensor unit and storing them in the data storage unit; And when calculating an angle between the first body part and the second body part using the first and second azimuth information, applying the first to fourth origin offset sizes stored in the data storage It may include calibrating the origin offset of each of the first and second magnetic fluxgate sensor units.

In example embodiments, the step of calibrating the origin offset may include: applying the first and second origin offset sizes when the first magnetic fluxgate sensor unit calculates the first orientation information; And applying the third and fourth origin offset sizes when calculating the second orientation information by the second magnetic fluxgate sensor unit.

In example embodiments, the'calibrating the origin offset' includes the first to fourth orientation information provided from the first and second magnetic fluxgate sensor units in the control unit. It may further include calculating the angle by applying the origin offset size.

In example embodiments, the first to fourth origin offset sizes are determined while the foldable device rotates 360 degrees while being positioned parallel to at least two of the xy plane, the yz plane, and the zx plane. , Each of the first and second magnetic fluxgate sensor units, by measuring the voltage peak occurrence point in the pickup voltage profile of each of the first and second fluxgate elements, respectively, to obtain a change trajectory of the voltage peak occurrence point in the corresponding plane. step; The maximum value (Xmax) and minimum value (Xmin) in the x-axis direction, the maximum value (Ymax) and the minimum value (Ymin) in the y-axis direction, and the maximum value in the z-axis direction in the change trajectory of the voltage peak occurrence point in each plane Obtaining (Zmax) and a minimum value (Zmin); And calculating the first to fourth origin offset sizes (X_offset, Y_offset, Z_offset) of each of the first and second fluxgate elements of each of the first and second magnetic fluxgate sensor units using the following equation. It can be obtained through

X_offset = (Xmax + Xmin)/2

Y_offset = (Ymax + Ymin)/2

Z_offset = (Zmax + Zmin)/2

In example embodiments, the performing of the calibration includes: a measurement sensitivity in an x-axis direction, a measurement sensitivity in a y-axis direction, and a z-axis direction of each of the first and second magnetic fluxgate sensor units. Obtaining a measurement sensitivity of; Obtaining a sensitivity gain for each of the measurement sensitivity in the x-axis, y-axis, and z-axis directions; And removing a deviation between the measurement sensitivity in the x-axis, y-axis, and z-axis directions by applying a sensitivity gain of the corresponding axis to each of the measurement sensitivity in the x-axis, y-axis, and z-axis directions. . The sensitivity gain may be determined as a ratio between a difference between a maximum value and a minimum value of a magnetic field used when calibrating an origin offset, and a difference between a maximum value and a minimum value at the point of occurrence of a measured voltage peak.

According to the present invention, the angle between the two body parts can be accurately measured in real time by arranging each of the magnetic sensor parts on two body parts of the foldable device that is the target of the distance measurement. Since the method of measuring the angle between the two bodies according to the present invention is not a measurement method using gravitational acceleration, but a measurement method using the Earth's magnetic field, the angle between two body parts can be accurately measured even while the entire or part of the foldable device is performing an acceleration motion. This is because the orientation information output from the magnetic sensor units installed in each body portion is coordinate information of a specific point in a three-dimensional coordinate system based on the origin on the folding axis of the two body portions of the foldable device. This is because even if the entire or part of the foldable device accelerates, it has no effect on the orientation information.

According to the inter-angle measurement apparatus according to the present invention, the orientation information of the two body parts measured by the magnetic sensor units is affected only by the size of each direction of the Earth's magnetic field applied from the outside. Even if the power of the foldable device is turned off and then turned on again, if there is no change in the magnitude of the Earth's magnetic field applied from the outside, the orientation information of the two body parts also remains unchanged by turning on after power off. In other words, since there is no error in measuring the angle between the two body parts due to the power on/off, the angle between the two bodies can be accurately measured.

1 is a block diagram showing a configuration of an apparatus for measuring an angle between two body parts that are foldable and coupled to a foldable device according to an exemplary embodiment of the present invention.
FIG. 2 illustrates a case in which the device for measuring an angle between the angles of FIG. 1 is applied to a portable foldable device according to an embodiment of the present invention.
3 is a diagram illustrating a configuration of a 3-axis magnetic fluxgate sensor unit used as an exemplary embodiment of the first and second magnetic sensor units in the apparatus for measuring an angle between the foldable device according to an embodiment of the present invention,
4 conceptually illustrates an internal configuration of a three-axis fluxgate element of a magnetic fluxgate sensor unit.
FIG. 5 is a block diagram showing the configuration of an apparatus for measuring an angle between two body parts of a foldable device implemented using two magnetic fluxgate sensor parts according to an embodiment of the present invention.
6 is an exemplary diagram for explaining an operating principle of a fluxgate device for measuring the strength of an externally applied magnetic field (earth magnetic field).
7 is a flowchart illustrating a method of measuring an angle between two body parts of a foldable device according to an embodiment of the present invention.
FIG. 8 is a waveform diagram illustrating a method of measuring the point of occurrence of a voltage peak from a profile of a pick-up voltage induced due to a magnetic field generated when an AC driving current flows through the driving coil and an external magnetic field applied to the pickup coil.
9 is a flowchart illustrating a method of generating first and second orientation information representing directions directed by first and second body parts from a pickup voltage profile according to an exemplary embodiment of the present invention.
FIG. 10 is a flowchart specifically showing a procedure of calculating time intervals between first and second voltage peaks in step S120 of FIG. 9.
11 is a diagram illustrating a method of calibrating a magnetic fluxgate sensor unit according to an exemplary embodiment of the present invention.
12 is a flowchart illustrating a procedure of measuring an angle between two body parts by applying calibration to magnetic fluxgate sensor parts according to an exemplary embodiment of the present invention.
13 shows a result of simulation of the performance of the apparatus for measuring an angle between two body parts of a foldable device according to the present invention.

Hereinafter, an apparatus and method for measuring an angle of a foldable device according to the present invention will be described with reference to the accompanying drawings. In this process, the thickness of the lines or the size of components shown in the drawings may be exaggerated for clarity and convenience of description. In addition, terms to be described later are terms defined in consideration of functions in the present invention and may vary according to the intention or custom of users or operators. Therefore, definitions of these terms should be made based on the contents throughout the present specification.

1 is a block diagram showing the configuration of a device for measuring an angle between two body parts joined in a foldable structure according to an exemplary embodiment of the present invention.

Referring to FIG. 1, an apparatus 20 for measuring an angle between a foldable device according to an exemplary embodiment may include a first magnetic sensor unit 13, a second magnetic sensor unit 14, and a control unit 15. have. The first magnetic sensor unit 13 and the second magnetic sensor unit 14 may be respectively installed on the first and second body portions of the foldable device coupled to be foldable.

In an exemplary embodiment, the first magnetic sensor unit 13 and the second magnetic sensor unit 14 may be implemented as vector magnetometers that measure components of the Earth's magnetic field. An azimuth and an inclination angle may be measured by using components of the magnetic field strength measured using three orthogonal vector magnetic sensor units. The vector magnetic sensor unit applicable to the present invention includes a rotating coil magnetometer, a Hall effect magnetometer, a magneto-resistive device, a fluxgate magnetometer, and the like. Can be lifted. However, it is not necessarily limited to this, and any magnetic sensor capable of detecting geomagnetic can be used as the magnetic sensor unit of the present invention.

The first and second magnetic sensor units 13 and 14 detect the behavior of the first and second body parts, respectively, and generate first and second orientation information indicating the directions in which the first and second body parts are respectively directed. It can be output to the control unit 15.

The control unit 15 may calculate an angle between the first body portion and the second body portion by using the orientation information provided by the first and second magnetic sensor portions 13 and 14. The control unit 15 may be implemented as a hardware component, a software component, and/or a combination of a hardware component and a software component. The control unit 15 includes, for example, a central processing unit (CPU), a processor, a System on Chip (SoC), a controller, an arithmetic logic unit (ALU), a digital signal processor, a microcomputer, It may be implemented in hardware such as a field programmable array (FPA), programmable logic unit (PLU), a microprocessor, or any other device capable of executing and responding to instructions, and software having a predetermined function. The software may include various functions described below, including a function of calculating an angle between two body parts using the first and second orientation information. Details on this will be described later.

In an exemplary embodiment, the inter-angle measurement device 20 may further include first and second interface units 11 and 12. Each of the first and second interface units 11 and 12 receives a predetermined instruction or request from a user through an input means, transmits it to the control unit 15, and processes the control unit 15 according to the received instruction or request. Interfacing with the user can be performed by outputting the result through the output means. The foldable device may be defined as an electronic device including first and second interface units 11 and 12. The first and second interface units 11 and 12 may be a part of the first body and the second body of the foldable device.

For example, the first interface unit 11 may include an input device such as a keyboard for receiving an operation from a user, and the second interface unit 12 is a user input through the first interface unit 11. It may be a configuration unit including a display unit for outputting the result of the instruction according to the manipulation of to the user. In this case, the foldable device 10 may be implemented as an electronic device such as a notebook computer. As another example, the first and second interface units 11 and 12 may be touch screen units implemented as displays such as LCD, LED, or OLED. The first and second interface units 11 and 12 may provide an interfacing function with a user through a method of receiving a touch manipulation from a user and outputting a processing result of an instruction according thereto. In this case, the foldable device 10 may be implemented as an electronic device such as a foldable smartphone or a foldable tablet PC.

FIG. 2 illustrates a case in which the device 20 for measuring the angle between the portable foldable device 30 is applied.

Referring to FIG. 2, the portable foldable device 30 may include first and second body parts 32 and 34, a coupling part 35, and a flexible display 40. The first body portion 32 and the second body portion 34 may be connected to each other through a connection unit 35. The coupling part 35 is disposed between one side of the first body part 32 and one side of the second body part 34 to combine the two so that they can be folded or unfolded. It may be a bonding structure. In addition, the first body portion 32 and the second body portion 34 may be folded or unfolded around the coupling portion 35. That is, the first body portion 32 and the second body portion 34 may be configured to allow a change in the angle θ between a folded position and an unfolded position. The first body portion 32 and the second body portion 34 may have a flat plate shape. The flexible display 40 may be disposed to cover all of the first and second body portions 32 and 34 and one surface of the coupling portion 35. In an exemplary embodiment, the first body part 32 and the second body part 34 may be directly connected to each other without using a separate coupling part 35 as a medium. In that case, the boundary line between the first body portion 32 and the second body portion 34 connected to each other may be the folding shaft 37.

The coupling portion 35 may be implemented with, for example, a hinge mechanism. The hinge structure is connected to the first body part 32 and the second body part 34, respectively, and the first body part 32 and the second body part 34 are folded in a folded state (interval angle θ = 0˚). It can make it possible to change the state into a state (interval angle θ = 180˚) or vice versa. Specific examples of the portable foldable device 30 including a hinge structure are disclosed by U.S. Patent Publications US2017-0364123A, US2018-0024593A, US2019-0079561A, etc., including the contents disclosed in these publications as part of the present invention. I want to.

The first and second interface units 11 and 12 may be implemented in various forms within a range capable of providing an interfacing function with a user through a user's manipulation input and instruction result output. In an exemplary embodiment, the first and second interface units 11 and 12 may be implemented as a touch screen unit. For example, when the first body part 32 and the second body part 34 have an angle between the first body part 32 and the second body part 34 smaller than a predetermined angle, the first and second interface units 11 and 12 are independently It can be controlled to operate as a separate interface unit. In this case, one flexible display 40 is functionally divided by the coupling part 35 to function as a display 40a for the first interface unit and a display 40b for the second interface unit 12. have. In this case, the display 40c on the coupling part 35 may function as a blank area. In addition, when the angle θ between the first body portion 32 and the second body portion 34 is greater than or equal to a predetermined angle, the controller 15 is a single interface unit in which the entire displays 40a, 40b, and 40c are integrated. It can be controlled to operate as. In this case, the integrated interface unit can provide an enlarged screen compared to the previous case. The foldable device 10 may also be implemented as various types of electronic devices having a structure in which the first and second body parts 11 and 12 described above are coupled to each other to be foldable with respect to the coupling part 35. .

In an exemplary embodiment, in order to measure the angle between the first body part 32 and the second body part 34, the first magnetic sensor part 13 is installed in the first body part 32, and the second A second magnetic sensor unit 14 may be installed on the body 34. The controller 15 may be installed on one of the first body 32 and the second body 34 to be electrically connected to the first and second magnetic sensor parts 13 and 14. This control unit 15 may be adopted as a means for controlling the overall operation of the foldable device 30 or may be a dedicated control unit introduced for the purpose of measuring an interposition angle according to the present invention.

In an exemplary embodiment, between the first and second body parts 32 and 34 using only two magnetic sensor parts 13 and 14 respectively installed on the first body part 32 and the second body part 34 You can measure the angle. The first and second magnetic sensor units 13 and 14 may respectively output first and second orientation information directed by the first body 32 and the second body 34. Here, the first and second orientation information of the first and second body parts 32 and 34 may be expressed as coordinates in a three-dimensional coordinate system determined based on the Earth's magnetic field.

In an exemplary embodiment, the first and second magnetic sensor units 13 and 14 may be implemented as magnetic fluxgate sensors. FIG. 2 shows an example in which the first magnetic fluxgate sensor unit 50a and the second magnetic fluxgate sensor unit 50b are installed as the first and second magnetic sensor units 13 and 14.

The first magnetic fluxgate sensor unit 50a and the second magnetic fluxgate sensor unit 50b may be implemented as a three-axis fluxgate sensor, for example. The 3-axis fluxgate sensor includes an x-axis fluxgate element 62, a y-axis fluxgate element 64, and a z-axis that can detect magnetic field components in three directions perpendicular to each other: x-axis, y-axis, and z-axis. A fluxgate device 66 may be included.

In an exemplary embodiment, in the first magnetic fluxgate sensor unit 50a, the magnetic field measurement direction of the y-axis fluxgate element 64 is substantially parallel to the folding axis 37 direction (y-axis direction in FIG. 2), The magnetic field measurement direction of the x-axis fluxgate element 62 is substantially parallel to the first direction, and the height direction of the z-axis fluxgate element 66 is substantially parallel to the second direction. Can be installed. Here, the first direction is a direction substantially parallel to the plane of the first body 32. The second direction may be a substantially normal direction to the plane of the first body part 32. 2 illustrates a case in which the first direction is a direction substantially orthogonal to the folding shaft 37.

In an exemplary embodiment, in the second magnetic fluxgate sensor unit 50b, the magnetic field measurement direction of the y-axis fluxgate element 64 is substantially parallel to the direction of the folding axis 37, and the x-axis fluxgate element 62 ) May be installed in the second body portion 34 such that the magnetic field measurement direction of) is substantially parallel to the third direction, and the height direction of the z-axis fluxgate element 66 is substantially parallel to the fourth direction. Here, the third direction may be a direction substantially parallel to the plane of the second body part 34, and the fourth direction may be a substantially normal direction to the plane of the second body part 34.

In another exemplary embodiment, the first magnetic fluxgate sensor unit 50a and the second magnetic fluxgate sensor unit 50b do not include the y-axis fluxgate element 64, respectively, and the x-axis and z-axis fluxgates It may be implemented as a two-axis fluxgate sensor including only the elements 62 and 66. In this case, the arrangement directions of the x-axis fluxgate element 62 and the z-axis fluxgate element 66 of each of the first magnetic fluxgate sensor unit 50a and the second magnetic fluxgate sensor unit 50b are 3 It is the same as the arrangement direction in the axial fluxgate sensor.

The first and second magnetic fluxgate sensor units 50a and 50b disposed on the first and second body parts 32 and 34, respectively, are applied from the outside, regardless of the state in which the foldable device 30 is disposed. By detecting the strength of the magnetic field, an angle between the first and second body parts 32 and 34 may be measured. In addition, even when the foldable device 30 is powered off and then turned on again, the angle between the first and second body parts 32 and 34 can be accurately measured without separate calibration. This angle measurement may be performed using only the two magnetic fluxgate sensor units 50a and 50b. Since a separate sensor is not further required, the number of sensors can be minimized, and manufacturing cost of the foldable device 10 can be reduced.

3 shows the configuration of the three-axis magnetic fluxgate sensor unit 50 in detail. FIG. 4 exemplarily shows the internal configuration of the three-axis fluxgate elements 62, 64, and 66 of the magnetic fluxgate sensor unit 50.

3 and 4, the 3-axis magnetic fluxgate sensor unit 50 includes a printed circuit board (PCB) 52, a 3-axis fluxgate device 62, 64, 66, a driving/detecting unit 70, and It may include a packaging portion 54 that rigidly couples these (52, 62, 64, 66, 70) into one body.

The x-axis, y-axis, and z-axis fluxgate elements 62, 64, 66 of the 3-axis magnetic fluxgate sensor unit 50 each have magnetic field components in three directions (x, y, z-axis directions) that are orthogonal to each other. It may be mounted on the printed circuit board 52 so as to be detectable. The x-axis fluxgate element 62 is attached to the insulating substrate 62-1, the rod-shaped magnetic material 62-2 and the magnetic material 62-2 extending in the x-axis direction and disposed on the insulating substrate 62-1. A driving coil 62-3 having both ends of the winding and connected to the driving/detecting unit 70, and a pickup coil 62-4 wound around the magnetic body 62-2 and connected to the driving/detecting unit 70 may be included. The driving coil 62-3 and the pickup coil 62-4 may be wound around the magnetic body 62-2 in the form of a solenoid coil.

The y-axis fluxgate element 64 may also be configured substantially the same as the x-axis fluxgate element 62. That is, the y-axis fluxgate element 64 may also include an insulating substrate 64-1, a magnetic material 64-2, a driving coil 64-3, and a pickup coil 64-4. However, there is a difference only in that the rod-shaped magnetic body 64-2 extends in the y-axis direction.

The z-axis fluxgate element 66 may also include an insulating substrate 66-1, a magnetic material 66-2, a driving coil 66-3, and a pickup coil 66-4. However, in order to reduce the height of the z-axis fluxgate element 66, the magnetic body 66-2 may be configured in a form in which a plurality of magnetic bodies 66-2 having a low height are arranged on the same plane. The plurality of magnetic bodies 66-2 may be wound with one driving coil 66-3 and one pickup coil 66-4, respectively. That is, the driving coils 66-3 wound around the plurality of magnetic bodies 66-2 may be connected in series, and the pickup coil 66-4 may also be connected in series. Each magnetic body 66-2 may extend in a cylindrical or elliptical shape in the z-axis direction. The magnetic fluxgate sensor unit 50 configured in this form can reduce the height of the z-axis fluxgate element 66 in the z-axis direction, so that it is easy to mount in a small mobile electronic device such as a foldable smartphone.

The magnetic bodies 62-2, 64-2, 66-2 can be made of magnetic materials having low coercivity, high permeability, and fast saturation magnetization. For example, the magnetic bodies 62-2, 64-2, and 66-2 may be manufactured in a bar shape having a laminated thin film structure by alternately stacking a plurality of layers of a NiFe thin film with an Al ₂ O ₃ insulator thin film. Such magnetic bodies 62-2, 64-2, 66-2 may have a narrow hysteresis loop and a high squareness in a square shape.

The driving/detecting unit 70 converts the AC current (e.g., triangular wave, sine wave, etc.) necessary for driving each of the three-axis fluxgate elements 62, 64, 66 to each driving coil 62-3, 64-3, 66-3. Can supply to Pickup voltage is induced to each pickup coil (62-4, 64-4, 66-4) by the time-varying magnetic field generated by the driving current flowing through each driving coil (62-3, 64-3, 66-3). I can. The profile of the pickup voltage induced in each pickup coil (62-4, 64-4, 66-4) by the magnetization reversal characteristic of each magnetic body (62-2, 64-2, 66-2) A first voltage peak and a negative second voltage peak occur. Unless specifically blocked, an external magnetic field such as the Earth's magnetic field may be applied to each of the pickup coils 62-4, 64-4, and 66-4.

However, the spacing between the two voltage peaks may vary depending on the magnitude of the Earth's magnetic field applied to each of the pickup coils 62-4, 64-4, and 66-4 from the outside. Please refer to the description). In an environment in which the earth's magnetic field is applied, the driving/detecting unit 70 applies the magnetic body 62-5, hexagonal It is possible to detect the pickup voltage induced in the pickup coils 62-4, 64-4, 66-4. The driving/detection unit 70 shifts the point of occurrence of the voltage peak included in the detected profile of the pickup voltage. The intensity of the earth's magnetic field can be calculated by detecting the degree (the degree that the externally applied magnetic field is shifted compared to when the externally applied magnetic field is 0.) The voltage peak included in the profile of the pickup voltage at each period of the AC drive current is at two points. Since it may occur, the strength of the Earth's magnetic field can be calculated by calculating the time difference between the two voltage peaks, and the strength of the Earth's magnetic field can be mapped to the coordinates of a point in a three-dimensional coordinate system. The coordinates of a point can define an azimuth vector connecting the origin to the point in the three-dimensional coordinate system, which is the direction in which the body part 32 or 34 in which the fluxgate sensor part 50 is installed is directed. It may be representative information.

In this way, the first driving/detecting unit 70a of the first magnetic fluxgate sensor unit 50a may obtain a first orientation vector representing the direction in which the first body unit 32 is directed. In addition, the second driving/detecting unit 70b of the second magnetic fluxgate sensor unit 50b may obtain a second orientation vector representing the direction in which the first body unit 32 is directed.

In obtaining the first and second orientation vectors, all of the three-axis fluxgate elements 62, 64, and 66 may be used as described above, but the x-axis fluxgate element 62 and the z-axis fluxgate element ( It is of course possible to use only 66).

The driving/detecting unit 70 is disposed on the printed circuit board 52 for a package together with the three-axis fluxgate elements 62, 64, 66, and the three-axis fluxgate elements 62, 64, and 66 through die bonding. And can be electrically connected. Then, it may be integrated through, for example, molding 54 using an epoxy resin.

The first magnetic fluxgate sensor unit 50a and the second magnetic fluxgate sensor unit 50b may be implemented as a three-axis magnetic fluxgate sensor unit 50 as illustrated in FIGS. 3 and 4. The first and second magnetic fluxgate sensor units 50a and 50b may be installed at arbitrary positions inside or outside the first body 32 and the second body 34, respectively. For example, the first magnetic fluxgate sensor unit 50a and the second magnetic fluxgate sensor unit 50b may be mounted inside the bezel or housing of the first body 32 and the second body 34, respectively. I can.

The x-axis fluxgate element 62 and the y-axis fluxgate element 64 of the first magnetic fluxgate sensor unit 50a have an arbitrary direction in which their magnetic field measurement direction is substantially parallel to the plane of the first body part 32. There may be two directions, and the magnetic field measurement direction of the z-axis fluxgate element 66 may be a substantially normal direction to the plane of the first body part 32. In this case, the magnetic field measurement direction of the y-axis fluxgate element 64 may be installed parallel to the direction of the folding axis 37, but is not limited thereto and may be installed tilted in the direction of the folding axis 37. have.

The same is true of the second magnetic fluxgate element 50b. The x-axis fluxgate element 62 and the y-axis fluxgate element 64 may be in any two directions whose magnetic field measurement directions are substantially parallel to the plane of the second body 34, and the z-axis fluxgate element The magnetic field measurement direction of 66 may be a direction substantially normal to the plane of the second body portion 34. In this case, the magnetic field measurement direction of the y-axis fluxgate element 64 may be installed parallel to the direction of the fold axis 37, but is not limited thereto and may be installed inclined with respect to the direction of the fold axis 37. Because the angle between the first straight line parallel to the plane of the first body part 32 and the second straight line parallel to the plane of the second body part 34 is always the same even if the direction of the first straight line and the second straight line changes. to be.

Throughout this specification, the meaning of'substantially parallel' with the planes of the body parts 32 and 34 is not only completely parallel in a strict sense, but a slight error (for example, an error within approximately ±10°) between two directions. It needs to be understood in the sense of including up to'parallel'. Likewise, the meaning of the'substantial normal direction' to the plane of the body parts 32 and 34 is also a slight error from the normal incidence direction as well as the complete normal incidence direction with respect to the plane of the body parts 32 and 34 (for example, about ±10˚). It needs to be understood as including'similar normal direction' with an error within). In the state of being installed in this way, the first magnetic fluxgate sensor unit 50a can detect the orientation information directed by the first body 32 while behaving together with the first body 32, and the second magnetic flux The gate sensor part 50b may detect direction information directed by the second body part 34 while moving together with the second body part 34. 3 shows the magnetic field measurement direction of the x-axis fluxgate device 62 of each of the first magnetic fluxgate device 50b and the second magnetic fluxgate device 50b is orthogonal to the folding axis 37 direction, and the y-axis flux The magnetic field measurement direction of the gate element 64 is an example of a case where it is installed in parallel with the direction of the folding shaft 37. Hereinafter, for convenience of understanding and description, a case in which the first magnetic fluxgate element 50b and the second magnetic fluxgate element 50b are installed as shown in FIG. 3 will be described as an example.

5 illustrates a configuration of an apparatus for measuring an angle between two bodies of a foldable device implemented using two magnetic fluxgate sensor units 50a and 50b according to an embodiment of the present invention.

Referring to FIG. 5, the first magnetic fluxgate sensor unit 50a may include a first fluxgate 60a and a first driving/detecting unit 70a. The second magnetic fluxgate sensor unit 50b may include a second fluxgate 60b and a second driving/detecting unit 70b.

In an exemplary embodiment, the first fluxgate 60a may be a three-axis fluxgate including x-axis, y-axis, and z-axis fluxgate elements 62, 64, and 66. In another embodiment, the first fluxgate 60a may be a two-axis fluxgate including the x-axis 62 and the z-axis fluxgate element 66. The second flux gate 60b may also have the same configuration as the first flux gate 60a. Hereinafter, unless otherwise specified, a two-axis fluxgate will be described as an example.

The first driving/detecting unit 70a may include a first fluxgate driving unit 72a and a first pickup signal processing unit 74a. The first fluxgate driving unit 72a includes driving coils 62-3, 64-3, 66- of the x-axis, y-axis, and z-axis fluxgate elements 62, 64, 66 of the first fluxgate 60a. AC drive current (eg, AC triangular wave, AC sinusoidal current, etc.) may be applied to 3). As a result, each of the driving coils 62-3, 64-3, 66-3 passes through an alternating current cycle of magnetic saturation (magnetization -> demagnetization -> magnetization in the reverse direction -> demagnetization, etc.) 64-2, 66-2).

The magnetic field and the earth magnetic field generated by the AC driving current flowing through the driving coils 62-3, 64-3, 66-3 are the x-axis, y-axis, and z-axis fluxgate elements 62 of the first fluxgate 60a. , 64, 66) of each pickup coil (62-4, 64-4, 66-4) can pass. Accordingly, a voltage can be induced in each of the pickup coils 62-4, 64-4, and 66-4. The first pickup signal processing unit 74a may detect pickup voltages induced to each of the pickup coils 62-4, 64-4, and 66-4, respectively. As mentioned above, first and second voltage peaks occur in the profile of each pickup voltage in every cycle due to the magnetization reversal characteristics of each of the magnetic bodies 62-2, 64-2, and 66-2. The time interval between the two voltage peaks may vary depending on the magnitude and direction of the Earth's magnetic field applied to the corresponding pickup coils 62-4, 64-4, and 66-4. By calculating the difference between the generation points of the two voltage peaks, the strength of the external magnetic field (that is, the earth's magnetic field) applied to the corresponding pickup coil can be calculated.

The strength of the external magnetic field applied to the three pickup coils 62-4, 64-4, and 66-4 can be calculated in this way. The intensity of the three external magnetic fields can be mapped to the coordinates of one point in the three-dimensional coordinate system. The orientation vector connecting from the origin of the 3D coordinate system to the one point may represent the orientation vector directed by the first body part 32 in which the first magnetic fluxgate sensor part 50a is installed. The first pickup signal processing unit 74a may provide the direction vector information obtained as above to the control unit 15.

The second driving/detecting unit 70b may also have the same configuration as the first driving/detecting unit 70a. Therefore, the second fluxgate driving unit 72b of the second driving/detecting unit 70b is the driving coil of each of the x-axis, y-axis and z-axis fluxgate elements 62, 64, 66 of the second fluxgate 60b. 62-3, 64-3, 66-3) can be applied to an AC driving current (eg, AC triangular wave, AC sinusoidal current, etc.). The second pickup signal processing unit calculates the strength of the external magnetic field applied to the three pickup coils 62-4, 64-4, 66-4, and uses it to determine the direction vector information directed by the second body part 34. Can be obtained and provided to the control unit 15.

The first driving/detecting unit 70a and the second driving/detecting unit 70b may be implemented with circuits and software configured to perform the above functions and signal processing operations. For example, it can be implemented with a dedicated ASIC chip and embedded program.

6 is an exemplary diagram for explaining the operating principle of the fluxgate elements 62, 64, 66 of the magnetic fluxgate sensor unit 50 according to an embodiment of the present invention.

Referring to Fig. 6 in detail, Figs. 6(a), (d), and (g) show the structure of a fluxgate device according to the present embodiment. In the drawing, a fluxgate element having a rod structure represents the x-axis and y-axis fluxgate elements 62 and 64, and a fluxgate element having a circular structure represents a z-axis fluxgate element 66. D is a driving coil, P is a pickup coil, and C is a magnetic material. 6(b), (e), and (h) show a hysteresis loop or MH (hysteresis loop) according to the magnetic properties of the magnetic body C constituting each of the fluxgate elements 62, 64, and 66. magnetization-magnetic field) loop). 6(c), (f), and (i) show waveforms of the pickup voltage generated in the pickup coil P.

With reference to (a), (b), and (c) of FIG. 6, it is assumed that there is no externally applied magnetic field (ie, the earth's magnetic field). When an AC current flows through the driving coil D, a triangular wave current (ie, driving current) represented by a dotted line in FIG. 6C as an example of an actual case flows, a magnetic field is formed inside the driving coil D. When the direction of the formed magnetic field is reversed, a voltage is induced in the pickup coil P. The voltage induced to the pickup coil P may be a waveform in the form of a voltage peak indicated by a solid line in (c) of FIG. 6. The occurrence of the voltage peak is closely related to the magnetic properties of the magnetic body C of the fluxgate device. That is, the voltage peak occurs because the voltage induced in the pickup coil P is proportional to the amount of change per time (that is, dM/dt) of the magnetization value of the magnetic body C. When a triangular wave current of one cycle flows through the driving coil D, the magnetization curve of the magnetic body C inside the fluxgate elements 62, 64, 66 follows the trajectory of the order ① to ⑧ in Fig. 6(b). Changes. When the magnetic body (C) has a magnetic hysteresis curve with an excellent angle ratio, the magnetization value may change rapidly in the ②~③ section where the magnetization direction of the magnetic body (C) changes from -M to +M. A first voltage peak may occur in the pickup coil P in a section in which a sudden change in magnetization value 2M occurs. Likewise, even in a section ⑥ to ⑦ in which one cycle of the triangular wave current is completed, a second voltage peak having the opposite sign from the first voltage peak may occur in the pickup coil P. At this time, the time interval T1 at which the first voltage peak and the second voltage peak occur is A μsec.

6(d), (e), and (f) show the case where an external magnetic field is applied from the left to the right of the fluxgate elements 62, 64, and 66. When, for example, an external magnetic field from left to right is applied to the fluxgate elements 62 and 64, the MH loop formed in the magnetic material C is applied to the magnetic material C as shown in FIG. 6(e). It may be shifted to the right, for example, by the amount of the external magnetic field. An external magnetic field such as the Earth's magnetic field can act as a DC bias magnetic field. That is, the external magnetic field can expand a magnetic domain composed of magnetic spindles that are substantially parallel to the magnetic field application direction inside the magnetic body (C), and due to the expansion of the magnetic domain, the MH loop is positive based on the origin. It can be shifted in the direction of or negative. In that state, when an AC triangular wave current is applied to the driving coil D, a solenoid magnetic field is alternately formed inside the driving coil D according to the current flow in the driving coil D. In this case, since the hysteresis curve is shifted to the right, for example, when magnetization reversal occurs based on the same time, the generation of the peak voltage has a different behavior than when there is no external magnetic field. In other words, when the magnetic material (C) changes from the (-) magnetized state to the (+) magnetized state, the (+) peak voltage occurs at a later time than when there is no external magnetic field, and the magnetic material (C) becomes (+) magnetized. As the state changes from the state to the negative (-) magnetization state, the (-) peak voltage occurs in a faster time than when there is no external magnetic field. Accordingly, the distance between the output peaks has a wider peak-to-peak distance compared to the case where there is no externally applied magnetic field. As shown in (f) of FIG. 6, the distance between the first and second voltage peaks detected by the pickup coil P becomes narrower than when an external magnetic field is not applied. That is, the time interval T2 at which the first and second voltage peaks occur is T2 = B μsec, and is decreased from T1.

6(g), (h), and (i) show the case when the external magnetic field is applied from the right to the left, for example, of the fluxgate elements 62, 64, 66, as opposed to the previous case. The same principle as in (d), (e), and (f) of FIG. 6 is applied, and when an external magnetic field is applied from right to left to the fluxgate elements 62, 64, 66, the first and second voltage peaks The time interval T3 at which the distance increases and the first and second voltage peaks occur is T3 = C μsec, which is higher than T1.

On the other hand, the magnetic field (B) formed in the driving coil (D) by the driving current in the solenoid-type fluxgate elements (64, 64, 66) and the electromotive force (E) induced in the pickup coil (P) are calculated as follows: It can be derived by equations 1 and 2.

In Equation 1, μ=4π x 10 ^-7 (Tm/A), n is the number of windings per unit length of the driving coil D, and I is the driving current. In Equation 2, L is the inductance of the pickup coil (P), di/dt is the current change that induces electromotive force in the pickup coil (P), ㅼ is a constant according to the characteristics of the magnetic material, and N is the winding of the pickup coil (P). The number, S is the cross-sectional area of the pickup coil P, and l is the average magnetic path length.

As can be seen from the above equation, the electromotive force induced in the pickup coil of the fluxgate element, that is, the pickup voltage, is determined only by the current, the number of windings, and the characteristics of the magnetic material. Unlike the method of using the electron flow inside the sensor, which is mainly used in conventional sensors such as Hall sensors, the fluxgate element has no possibility of intervening problems such as changes in external environment such as temperature and electromagnetic waves. Therefore, when the magnetic properties of the fluxgate sensor 50 are fixed and the design and specifications of the fluxgate device such as current and number of windings are determined, the orientation data (external magnetic field component) of the magnetic field measurement direction of each of the three-axis fluxgate devices is determined. You can get it.

According to this operating principle, each fluxgate element 62, 64, 66 of the magnetic fluxgate sensor unit 50a, 50b measures externally applied magnetic fields, that is, the X-axis, Y-axis and Z-axis components of the Earth's magnetic field. can do. Accordingly, the first and second magnetic fluxgate sensor units 50a and 50b are irrespective of the arrangement state of the foldable device 30 and power on/off operation, the first body portion 32 and the second body portion ( First and second orientation information representing the direction in which 34) is directed may be output, respectively. The first and second orientation information may be expressed as three-dimensional coordinates in a coordinate system determined based on the Earth's magnetic field.

The control unit 15 calculates the angle between the first and second body parts 32 and 34 using first and second orientation information respectively output from the first and second magnetic fluxgate sensor units 50a and 50b. can do. Specifically, the first and second azimuth information may be mapped to 3D coordinates in a 3D coordinate system, and thus may correspond to the first and second azimuth vectors, respectively. Accordingly, an angle between the first and second orientation vectors may be an angle between the first body portion 32 and the second body portion 34. The controller 15 may measure the angle between the first and second body parts 32 and 34 by calculating the angle between the first and second orientation vectors based on this principle. That is, the control unit 15 includes a first orientation vector formed by a three-dimensional coordinate corresponding to the origin of the coordinate system and the first orientation information, and a first orientation vector formed by a three-dimensional coordinate corresponding to the origin of the coordinate system and the second orientation information. The angle between the first and second body parts 32 and 34 may be measured by calculating the angle between the two orientation vectors.

In an exemplary embodiment, when the angle between the first and second body parts 32 and 34 is measured, the control unit 15 performs a predetermined subsequent processing according to the angle between the first and second body parts 32 and 34. Can be done. The predetermined subsequent processing may be, for example, varying the interface mode provided to the user through the first and second interface units 11 and 12. When the first and second interface units 11 and 12 are implemented as a touch screen display, the control unit 15 controls the first and second interface units according to the angle between the first and second body parts 32 and 34. Change the size of the image or video output through (11, 12), output the image or video only through one of the first and second interface units (11, 12), or Different images or images may be output through the interface units 11 and 12, respectively. Through this method, the interface mode of the first and second interface units 11 and 12 may be varied, and the interface mode variable operation of various methods may be implemented according to the intention of the designer without being limited to the above example.

7 is a flowchart illustrating a method of measuring an angle between two body portions 32 and 34 of the foldable device 30 according to an embodiment of the present invention.

A method of measuring an angle of the foldable device 30 according to an embodiment of the present invention will be described with reference to FIG. 7. First, the first and second magnetic fluxgate sensor units 50a and 50b detect the behavior of the first and second body parts 32 and 34, respectively, so that the first and second body parts 32 and 34 are respectively First and second orientation information representing the direction to be directed may be generated. The controller 15 receives first and second orientation information of the first and second body parts 32 and 34 from the first and second magnetic fluxgate sensor parts 50a and 50b, respectively (S100).

In step S100, the first and second magnetic fluxgate sensor units 50a and 50b may respectively output first and second orientation information determined according to the magnitude of an externally applied magnetic field such as the Earth's magnetic field.

While the driving current is applied to the driving coils 62-3, 64-3, 66-3 of each fluxgate element 62, 64, 66, the magnetic material 62-2, 64-2, 66-2 The pick-up voltage is induced in each of the pick-up coils 62-4, 64-4, and 66-4 by the magnetization reversal characteristic. In the profile of the pickup voltage, positive and negative voltage peaks may occur every period. In the pick-up voltage profile of one period, the points of occurrence of the first and second voltage peaks are shifted according to the magnitude of an externally applied magnetic field such as the earth's magnetic field. Each fluxgate element 62, 64, 66 is applied to each fluxgate element 62, 64, 66 using the shift degree of the first and second voltage peaks or the time interval between the first and second voltage peaks. The magnitude of the Earth's magnetic field component can be detected. The magnitude of the triaxial component of the earth's magnetic field detected by each fluxgate element 62, 64, 66 of the first magnetic fluxgate sensor unit 50a is the direction of the first body 32 in which it is installed. It may be representative first direction information. That is, the first orientation information may be information on the magnitude of an external magnetic field component detected by each fluxgate element of the first magnetic fluxgate sensor unit 50a, and this information is the voltage peak appearing in the pickup voltage profile of the corresponding fluxgate element. It may be obtained from information about the occurrence time of Similarly, the magnitude of the magnetic field detected by each fluxgate element 62, 64, 66 of the second magnetic fluxgate sensor unit 50b in the three-axis direction represents the direction of the second body part 34 in which it is installed. It may be the second direction information. The second orientation information may also be obtained from information on the occurrence time of the voltage peak appearing in the pickup voltage profile of the corresponding fluxgate device. A series of signal processing operations for extracting the first and second orientation information from the pickup voltage induced in the pickup coil P may be performed by the first and second pickup signal processing units 74a and 74b.

8 is a magnetic field generated when an AC driving current (A) flows through the driving coil and an external magnetic field is applied to the pickup coil, so the method of measuring the point of occurrence of a voltage peak from the profile (B) of the induced pickup voltage It is a waveform diagram. 9 is a flowchart illustrating a method of generating first and second orientation information representing directions directed by first and second body parts from a pickup voltage profile according to an exemplary embodiment of the present invention. FIG. 10 is a flowchart specifically showing a procedure of calculating time intervals between first and second voltage peaks in step S120 of FIG. 9.

The first fluxgate sensor unit 50a installed on the first body 32 will be described with reference to FIGS. 8 to 10 as an example. The following description can be equally applied to the second fluxgate 50b installed on the second body 32. In addition, it will be described as an example that the first and second fluxgate sensor units 50a and 50b have a 3-axis fluxgate element. However, only the first and second body parts 32, 34 can detect magnetic field components in a direction substantially parallel to the plane of each body part 32, 34 and a direction substantially normal to the plane. 34) It is possible to measure the angle between the liver.

The first fluxgate driving unit 72a drives an AC triangular wave as shown in Fig.8(A) with a one-period waveform in each driving coil 62-3, 64-3, 66-3 of the first fluxgate 60a. Current can be supplied (S112, S114).

While the driving current flows through each of the driving coils 62-3, 64-3, 66-3, each of the driving coils 62-3, 64-3, 66-3 functions as a solenoid and a magnetic material 62-2 , 64-2, 66-2). The time-varying magnetic field penetrates the inside of the pickup coils 62-4, 64-4, 66-4, and the profile shown in Fig. 8(B) in each of the pickup coils 62-4, 64-4, 66-4 Pickup voltage (V _out ) having a can be induced. The first pickup signal processing unit 74a may detect analog pickup voltage V _out signals from each of the pickup coils 62-4, 64-4, and 66-4 (S116).

The first pickup signal processing unit 74a amplifies the analog pickup voltage V _out signals, performs filtering processing to remove noise, and then performs signal processing such as chopping to convert the digital data of the pickup voltage profile. Yes (S118).

Furthermore, the first pick-up signal processing unit 74a may find the point of occurrence of the voltage peak by using digital data of each of the converted pick-up voltage profiles (S120). In the pickup voltage profile of each of the fluxgate elements 62, 64, and 66, a voltage peak generation point for each cycle may be a value corresponding to the magnitude of an external magnetic field applied to the corresponding fluxgate element. For example, the point of occurrence of the voltage peak detected in the pickup voltage profile of the x-axis fluxgate device 62 may be a value corresponding to the magnitude of a component in the x-axis direction of an external magnetic field applied to the x-axis fluxgate device 62. During one period of the pickup voltage profile, the voltage peak can occur twice. In an exemplary embodiment, the first pickup signal processing unit 74a generates a positive first voltage peak (V _p ) in the pickup voltage profile of each of the three fluxgate elements 62, 64, and 66 every cycle ( P1) and the occurrence point P2 of the negative second voltage peak (-V _p ) can be detected. The time interval T _d between the two voltage peaks V _p and -V _p occurrence points P1 and P2 can be calculated.

The flowchart of FIG. 10 shows the procedure of step S120 in more detail. Referring to FIG. 10, in step S120, for example, from the pickup voltage profile data of the current period of the x-axis fluxgate element 62 aligned in the first direction, two voltage peaks (V _p , -V _p ) occur at the time points (P1, P2). How to detect is described in more detail.

For example, from the pickup voltage profile data of the current period of the x-axis fluxgate element 62, a value representing the magnitudes of voltages of the initial predetermined section Sb may be determined and calculated as the base voltage V _b . For example, the base voltage V _b of the current period may be determined as an average value, a median value, etc. of the voltages of the initial predetermined period Sb (S130).

A first reference voltage (+V _r ) may be obtained by adding a gap voltage (V _g ) of a predetermined size to the base voltage (V _b ) of the current period (S132 ). The gap voltage V _g may be determined to be a value having a sufficient size to distinguish between the noise and the peak voltage so as to avoid erroneous detection due to noise. At the same time, a second reference voltage (-V _r ) having the same magnitude as the first reference voltage (+V _r ) and opposite signs can be obtained.

Two reference voltages (+V _r , -V _r ), which are positive and negative, are calculated, and then the voltage values after the predetermined period (Sb) in the pickup voltage profile of the current period are calculated as first and second reference voltage values (+V _r , Compared with -V _r ), two points of time (P1, P2) that become equal to each other may be detected (S134). The two detected time points P1 and P2 may be times when the pickup voltage enters the section of the first voltage peak (+V _p ) and the section of the second voltage peak (-V _p ), respectively. The time interval between the two viewpoints P1 and P2 is the first direction component of the external magnetic field applied to the pickup coil 62-4 of the x-axis fluxgate element 62 arranged to measure the magnetic field in the first direction. It can be viewed as a value corresponding to the size.

Assume that the first pickup signal processing unit 74a outputs the magnitude of the external magnetic field applied to the x-axis fluxgate element 62, that is, the first direction component of the Earth's magnetic field, as, for example, 10-bit digital data. In this case, it is possible to detect the two times P1 and P2 by dividing one period into 1024 times. Of course, it is also possible to detect the two viewpoints P1 and P2 by dividing one period into a larger number of viewpoints than, for example, 1024 viewpoints. When the externally applied magnetic field is 0, the time interval between the two viewpoints P1 and P2 may be output as a value of 512. Depending on the magnitude of the first direction component of the externally applied magnetic field applied to the pickup coil 62-4 of the x-axis fluxgate element 62, the value of the time interval between the two points of time (P1, P2) may increase or decrease from 512. I can. For example, suppose that the x-axis fluxgate element 62 is fabricated so that the time interval between the two viewpoints P1 and P2 increases by 70 from 512 to 582 when an external magnetic field of 0.5 Gauss is applied. When the sign of the externally applied magnetic field is changed and a magnetic field of -0.5 Gauss is applied to the pickup coil 62-4, the time interval between the two points of time P1 and P2 decreases from 512 to 70, and 432 may be output. This increase may be a value that linearly changes according to the magnitude of the first direction component of the externally applied magnetic field applied to the pickup coil 62-4 of the x-axis fluxgate element 62. When a magnetic field of 0.25 Gauss is applied from the outside, the time interval between the two viewpoints P1 and P2 can be measured as a displacement of 35.

The first pickup signal processing unit 74b of the first magnetic fluxgate sensor unit 50a has two voltages from the pickup voltage profile data of the current period of the z-axis fluxgate element 66 arranged to measure the magnetic field in the second direction. Peaks (V _p , -V _p ) occurrence points (P1, P2) can be obtained in the same way as above.

The same is true for the second magnetic fluxgate sensor unit 50b. The second pickup signal processing unit 74b includes two voltage peaks from the pickup voltage profile data of the current period of the x-axis and z-axis fluxgate elements 62 and 66 arranged to measure magnetic fields in the third and fourth directions. V _p , -V _p ) The point of occurrence (P1, P2) can be obtained in the same way as above.

The first pick-up signal processing unit 74a is the first magnetic flux gate sensor unit 50a of the x-axis fluxgate element 62 of the pickup voltage profile measured every period between the two voltage peak generation points (P1, P2). One time difference can be calculated. In addition, in the pickup voltage profile of the z-axis fluxgate element 62 of the first magnetic fluxgate sensor unit 50a, a second time difference between the two voltage peak generation points P1 and P2 measured every period may be calculated. (S136). The second pickup signal processing unit 74a also generates a voltage peak from the two pickup voltage profiles of the x-axis and z-axis fluxgate elements 62 and 66 of the second magnetic fluxgate sensor unit 50b in the same manner. The third and fourth time differences between the viewpoints P1 and P2 may be calculated.

In each of the first magnetic fluxgate sensor unit 50a and the second magnetic fluxgate sensor unit 50b, in step S120, time difference information between the two voltage peak generation points is obtained from the first and second body parts ( 32, 34) can be generated as the first and second orientation information (S122).

Step S122 will be described in detail. According to an exemplary embodiment, in calculating the angle between the first and second body parts 32 and 34, a direction substantially parallel to the plane of each of the first body part 32 and the second body part 34 and the plane It is necessary to measure the external magnetic field component in the substantially normal direction. In measuring the external magnetic field component in a direction substantially parallel to the plane of each of the first body portion 32 and the second body portion 34, the x-axis fluxgate element 62 and the y-axis fluxgate element 64 Both detection information may be used, but only one of the two detection information may be used. However, the magnetic field measurement direction of the fluxgate element used to measure the external magnetic field needs to be a direction not parallel to the folding axis 37.

The first driving/detecting unit 70a includes the first and second voltage profiles of the first fluxgate 60a, for example, the x-axis fluxgate device 62 and the z-axis fluxgate device 66 at each pickup voltage profile. You can find the time difference. The first and second time difference may be first orientation information of a corresponding period. Likewise, the second driving/detecting unit 70b includes the third and third voltage profiles of the second fluxgate 60b, for example, the x-axis fluxgate element 62 and the z-axis fluxgate element 66 each The fourth time difference (information on the occurrence time of the voltage peak) can be obtained respectively. The third and fourth time differences may be second orientation information of a corresponding period.

In another exemplary embodiment, the first pick-up signal processing unit 74a is the point of occurrence of two voltage peaks measured every cycle in the pickup voltage profile of the y-axis fluxgate element 64 of the first magnetic fluxgate sensor unit 50a. The fifth time difference between (P1, P2) may be further calculated. This information may be further included in the first orientation information. The second pick-up signal processing unit 74b is also a second voltage peak between the two voltage peak generation points P1 and P2 measured every period in the pickup voltage profile of the y-axis fluxgate element 64 of the second magnetic fluxgate sensor unit 50b. 6 more time difference can be calculated. This information may be further included in the second orientation information.

Each of the first orientation information and the second orientation information has a fold axis 37 of the first body part 32 and the second body part 34 as a y-axis, and a point on the fold axis 37 It can be viewed as coordinate information mapped to a point in the 3D coordinate system as the origin. The first orientation information may be a first orientation vector representing a direction in which the first body 32 is directed in the 3D coordinate system. Likewise, the second orientation information may be a second orientation vector indicating a direction in which the second body portion 34 is directed in the 3D coordinate system.

In a three-dimensional coordinate system in which a point on the folding axis 37 of the first body part 32 and the second body part 34 is an origin, the first and second time difference information or the first, second and second The first azimuth information composed of 5 time difference information may be mapped to the coordinates of one point in the three-dimensional coordinate system to be information representing the azimuth phase θ ₁ directed by the first body 32. Similarly, the third and fourth time difference information or the third, fourth and sixth time difference information is also mapped to the coordinates of another point in the three-dimensional coordinate system, so that the azimuth phase (θ) directed by the second body part 34 is ₂ ) can be representative information.

The first, second, or fifth time difference information and second, fourth, or sixth time difference information detected by the first and second pickup signal processing units 74a and 74b respectively 2 Initial calibration may be performed on each of the first and second magnetic fluxgate sensor units 50a and 50b in order to convert to the azimuth angle information directed by the body part 34. The origin point offset 115 of each fluxgate element 62, 64, 66 of the first and second magnetic fluxgate sensor units 50a, 50b obtained through the calibration is first and second orientations It can be reflected when calculating information. In the initial calibration process, a sensitivity gain can be obtained and the sensitivity gain can be reflected. The reflection of the origin offset 115 and the sensitivity gain may be processed inside the first and second magnetic fluxgate sensor units 50a and 50b or may be processed by the controller 15. Details on obtaining and reflecting the origin offset 115 and the sensitivity gain will be described later.

The first and second pickup signal processing units 74a and 74b use the first and second azimuth information obtained as above as information representing the azimuth angles of the first body 32 and the second body 34, respectively, and the control unit 15 ) Can be provided (S124). The first and second orientation information may be provided to the control unit 15 by collecting information of each period or several periods.

The series of processing from step S114 to step S124 for obtaining the first orientation information and the second orientation information may be continuously repeatedly performed every cycle of the AC drive current until an instruction to terminate the measurement of the interval angle is given. (S126, S128).

As an exemplary embodiment, instead of obtaining the time difference between the first and second voltage peaks (P1, P) in step S120, the first voltage peak (+V _p ) occurs (P1) or the second voltage It is also possible to obtain only the point of occurrence (P2) of the peak (-V _p ). The magnitude of the external magnetic field can be determined by only information on the occurrence point P1 of the first voltage peak (+V _p ) or the occurrence point P2 of the second voltage peak (-V _p ). The magnitude of the external magnetic field can be known by using the time interval between the time when the voltage peak occurs when no external magnetic field is applied and the time when the voltage peak occurs when the external magnetic field is applied.

As another exemplary embodiment, in calculating the voltage peak generation time (refer to steps S118 and S120), the voltage peak generation time may be calculated using the analog pickup voltage profile as it is without converting to digital data. For this purpose, it is necessary to provide a separate circuit for detecting the point of occurrence of the voltage peak.

Meanwhile, after step S100, the controller 15 may calculate the angle between the first and the body parts 32 and 34 using the first and second orientation information input in step S100 (S200). In step S200, the controller 15 may measure an angle between the first and the body parts 32 and 34 by calculating an angle between the first and second orientation vectors.

)와 제2 방위벡터(

)간의 사이각(θ)은 아래 식을 이용하여 구할 수 있다.The first orientation vector (

) And the second orientation vector (

The angle (θ) between) can be obtained using the following equation.

)와 제2 방위벡터(

)간의 사이각(θ)은 제1 몸체부(32)와 제2 몸체부(34) 간의 사이각이다.The first direction vector obtained in this way (

) And the second orientation vector (

) Between the first body portion 32 and the second body portion 34 between the angle (θ).

The controller 15 may perform a predetermined follow-up operation according to the angle between the first and second body parts 32 and 34 calculated in step S200 (S300). The subsequent operation may be a predetermined control or processing. For example, according to the calculated size of the angle between the first and second body parts 32 and 34, control to change the interface mode provided to the user through the first and second interface units 11 and 12 is performed. I can.

If the first and second azimuth information provided by the first and second magnetic fluxgate sensor units 50a, 50b is information that has not been calibrated, the controller 15 performs calibration before calculating the inter-angle. Processing can also be performed. To this end, the size of the origin offset 115 of each fluxgate element of the first and second magnetic fluxgate sensor units 50a and 50b may be previously stored in the data storage unit of the control unit 15. Furthermore, the control unit 15 may also reflect the sensitivity gain.

11 is a diagram illustrating a method of calibrating a magnetic fluxgate sensor unit according to an exemplary embodiment of the present invention.

In the initial state of manufacture of the magnetic fluxgate sensor unit 50, the center point of the magnitude of the external magnetic field measured by each of the fluxgate elements 62, 64, 66 may be separated by a predetermined distance from the origin (O). The predetermined distance is referred to herein as the origin offset 115. If the origin offset 115 is not calibrated, an error may occur in measuring the angle between the two body parts 32 and 34. The origin offset 115 is the time difference from the start of one cycle of the pickup voltage in the pickup voltage profile of each fluxgate element of the magnetic fluxgate sensor unit 50 to the occurrence of a voltage peak when no external magnetic field is applied or It can be defined as the equivalent strength of the external magnetic field.

For example, the original position offset 115 of the first and second magnetic fluxgate sensor units 50a and 50b installed on the two body parts 32 and 34 of the foldable device 30, respectively, has not been calibrated yet. It is assumed to be in the initial state. The two body parts 32 and 34 are completely stacked on top of each other or spread to form the same plane, that is, when the angle between the two bodies 32 and 34 is 0 degrees or 180 degrees, for example, while being positioned parallel to the xy plane and rotating 360 degrees, You can measure the magnitude of the x-axis and y-axis components of the magnetic field. The center of the trajectory 110 of the x-axis and y-axis components of the external magnetic field obtained in this measurement may be separated from the origin O by the origin offset 115 as shown in FIG. 11. If you measure the angle in this state, accurate angle measurement cannot be made. For example, the first magnetic fluxgate sensor unit 50a outputs the maximum value (Xmax) of the x-axis component of the external magnetic field, and the second magnetic fluxgate sensor unit 50b determines the maximum value (Ymax) of the y-axis component. In the output state, before the origin offset 115 is calibrated, the size of the angle between the two body parts 32 and 34 is measured as α1, but the actual angle is α2 measured at the origin O. That is, if the origin offset 115 is not calibrated, an error of'α2-α1' may occur. The size of the origin offset 115 may be calculated in advance and applied to the calculation of the interposition angle. Through this, it is possible to more accurately calculate the interval angle.

12 is a flowchart illustrating a procedure of measuring an angle between two body parts by applying calibration to magnetic fluxgate sensor parts according to an exemplary embodiment of the present invention.

Referring to FIG. 12, first, the size of the origin offset 115 of the first and second magnetic fluxgate sensor units 50a and 50b installed on the two body parts 32 and 34 of the foldable device 30 is calculated. can do. The calculated origin offset size 115 may be stored in the data storage unit (S400).

In an exemplary embodiment, the two body parts 32 and 34 of the foldable device 30 are completely stacked on top of each other, or are unfolded to form the same plane (that is, a state in which the angle θ is 0 degrees or 180 degrees) ), the foldable device 30 is rotated 360 degrees while maintaining parallel to the xy plane. During the rotation, the voltage in the xy plane is measured by measuring the voltage peak occurrence point in the pickup voltage profile of each fluxgate element 62, 64, 66 of each of the first and second magnetic fluxgate sensor units 50a, 50b. The trajectory of change at the point of peak occurrence can be obtained. For example, while the foldable device 30 rotates 360 degrees, the change trajectory at the point of occurrence of the voltage peak in the pickup voltage profile of each of the first and second magnetic fluxgate sensor units 50a and 50b is a circle or an ellipse. , Or may be a crushed circle. As shown in FIG. 11, the change trajectory 110 at the point of occurrence of the voltage peak may have a maximum value (Xmax) and a minimum value (Xmin) in the x-axis direction, and a maximum value (Ymax) and a minimum value ( Ymin). Similarly, in the yz plane, the change trajectory at the point of occurrence of the voltage peak can be obtained from the pickup voltage profile of each fluxgate element in the same manner. Through this, the maximum value Zmax and the minimum value Zmin can be obtained in the z-axis direction. The center (O') of the change trajectory at the point of occurrence of the voltage peak in the three axis directions thus obtained does not coincide with the origin (O). The degree of inconsistency may correspond to the size of the origin offset 115.

The size of the origin offset 115 initially possessed by each of the fluxgate elements 62, 64 and 66 of the first and second magnetic fluxgate sensor units 50a and 50b can be calculated using the following equation.

The origin offset size obtained for each of the fluxgate elements 62, 64 and 66 of the first and second magnetic fluxgate sensor units 50a and 50b may be stored in advance in a data storage unit (not shown).

When calculating the angle between the two body parts 32 and 34, the origin offset obtained in advance and stored in the data storage unit can be applied. According to an exemplary embodiment, the origin offset may be reflected when the magnetic fluxgate sensor units 50a and 50b detect the first and second orientation information. That is, when generating the first and second orientation information in step S122 of the flowchart of FIG. 9, the corresponding origin offset size stored in the data storage units of the first and second magnetic fluxgate sensor units 50a, 50b is read, Can be reflected (S410).

Accordingly, the first and second azimuth information provided by the first and second magnetic fluxgate sensor units 50a and 50b to the control unit 15 in step S124 is azimuth information to which the origin offset size is applied. The controller 15 may calculate an angle between the first and second body parts 32 and 34 using the first and second azimuth information in which the size of the origin offset is calibrated (S420).

In addition, the control unit 15 may perform a predetermined control or process based on the calculated interval.

As another embodiment, the origin offset may be reflected in the control unit 15. In this case, the size of the origin offset may be previously stored in the data storage unit of the control unit 15. In step S124, the first and second magnetic fluxgate sensor units 50a and 50b may provide first and second azimuth information to the controller 15 in a state in which the origin offset is not calibrated. In step S200 of FIG. 7, the control unit 15 reads the origin offset size stored in the data storage unit and reflects it in the first and second orientation information provided by the first and second magnetic fluxgate sensor units 50a and 50b. can do. In this way, the angle between the first and second body parts 32 and 34 may be calculated by using the first and second azimuth information calibrated by the origin offset size.

Meanwhile, measurement sensitivity characteristics of the three-axis fluxgate elements 62, 64, and 66 of the magnetic fluxgate sensor unit 50 may be different from each other. That is, in FIG. 12, the x-axis measurement sensitivity Sx = Xmax-Xmin and the y-axis measurement sensitivity Sy = Ymax-Ymin may be different from each other. The z-axis measurement sensitivity Sz = Zmax-Zmin may also be different from the x-axis measurement sensitivity Sx and/or y-axis measurement sensitivity Sy. If the sensitivity characteristics of the three axes are not the same, the sensitivity characteristic trajectory is expressed as a distorted sphere rather than a perfect sphere. In order to remove the difference in the three-axis manufacturing and the sensitivity characteristic deviation due to the influence of the magnetic field applied from the surroundings, a sensitivity gain can be applied to each axis to normalize. Here, the sensitivity gain may be defined as a ratio between a difference between a maximum value and a minimum value of a magnetic field used when calibrating an origin offset and a difference between a maximum value and a minimum value at the point of occurrence of the measured voltage peak. The sensitivity gain can be applied by multiplying the sensitivity gain after reflecting the size of the origin offset at the time when the measured voltage peak occurs. The value obtained by applying the sensitivity gain in this way can be the magnitude of the magnetic field depending on the type of the gain, and can be unit vectors for each of the x, y, and z axes.

On the other hand, the origin offset can be obtained by other methods. Another way to obtain the origin offset size is to apply a magnetic field of the same size but opposite direction in both directions of the x-axis from the outside, and at that time, calculate the point of occurrence of the voltage peak, and the center value of these two values and the distance between the origin. The distance can also be calculated as the size of the origin offset on the x-axis. In the same manner, both the y-axis and the z-axis may be measured to calculate the offset size of the x, y, and z-axes.

13 shows a result of simulation of the performance of the apparatus for measuring an angle between two body parts of a foldable device according to the present invention.

Referring to the graph of FIG. 13, the horizontal axis is the actual angle between the two body parts 32 and 34, and the vertical axis is the magnetic fluxgate sensor part 50a, 50b and the two body parts 32, according to the embodiment of the present invention. It is a value obtained by measuring the angle between the two body parts 32 and 34 by using the angle measuring device 20 configured to be respectively disposed on 34). Although there is some error between the actual and measured angles, it can be seen that the overall trend of the two values changing from 0 degrees to 180 degrees is similar. By analyzing the pattern of the error that occurs between the actual angle and the measurement angle, you will be able to obtain an error correction amount that can offset the error. If you apply the error correction amount to the angle between measurements, you will get a more accurate measurement angle.

In the above, a method and apparatus for measuring an angle between two body parts have been described using a portable foldable device as an example. However, there is no particular limitation on the subject of the present invention. The present invention is not limited to the above embodiments, and the present invention can be widely used to measure an angle between two objects using a magnetic sensor.

Although the embodiments have been described by the limited drawings as described above, those skilled in the art will variously modify and change the present invention within the scope not departing from the spirit and scope of the present invention described in the following claims. You will understand that you can. For example, the described techniques are performed in a different order from the described method, and/or components such as a system, structure, device, circuit, etc. described are combined or combined in a form different from the described method, or other components Alternatively, even if substituted or substituted by an equivalent, an appropriate result can be achieved. Therefore, other implementations, other embodiments, and claims and equivalents fall within the scope of the claims to be described later.

20: device for measuring an angle between foldable devices
11: first interface unit 12: second interface unit
13: first magnetic sensor unit 14: second magnetic sensor unit
15: control unit 30: portable foldable electronic device
32: first body portion 34: second body portion
35: coupling portion 40: flexible display
50: magnetic fluxgate sensor unit
50a, 50b: first and second magnetic fluxgate sensor units
52: PCB for packaging 54: epoxy molding
62: X-axis fluxgate element 64: Y-axis fluxgate element
66: Z-axis fluxgate element 70: fluxgate driving circuit

Claims (20)

The first body part and the second body part are installed in the first body part of the foldable device in which the first body part and the second body part are foldable through a folding axis, and detect the magnitude of the external magnetic field applied to the first body part to determine the direction in which the first body part is directed. A first magnetic sensor unit configured to detect representative first orientation information;
A second magnetic sensor unit installed on the second body and configured to detect a magnitude of an external magnetic field applied to the second body to detect second azimuth information representing a direction in which the second body is directed; And
A control unit configured to receive the first orientation information and the second orientation information from the first and second magnetic sensor parts and calculate an angle between the first body part and the second body part around the folding axis. An apparatus for measuring an angle between two body parts of a foldable device, characterized in that. The method of claim 1, wherein in a three-dimensional coordinate system having a point on the folding axis as an origin, the first orientation information is determined by the magnitude of an external magnetic field component in at least the first direction and the second direction from the origin. Information that can be mapped to a first azimuth vector connecting a first point, and the second azimuth information connects a second point determined by the magnitude of the external magnetic field component in the third and fourth directions from the origin. It is information that can be mapped to a second orientation vector,
The first direction is an arbitrary direction substantially parallel to the plane of the first body part, the second direction is a substantially normal direction to the plane of the first body part, and the third direction is the plane of the second body part The apparatus for measuring an angle between two bodies of a foldable device, characterized in that it is a substantially parallel arbitrary direction, and the fourth direction is a substantially normal direction to a plane of the second body part. The method of claim 2, wherein the control unit obtains the first orientation vector mapped by the first orientation information and the second orientation vector mapped by the second orientation information, respectively, and the first orientation vector and the second orientation vector are respectively obtained. An apparatus for measuring an angle between two bodies of a foldable device, characterized in that configured to calculate an angle between two orientation vectors. The method of claim 1, wherein the first magnetic sensor unit comprises a first fluxgate element configured to detect an external magnetic field component in at least a first direction, a second fluxgate element configured to detect an external organ field component in a second direction, and at least Each of the first and second driving currents required for driving the first and second fluxgate devices is applied, and the first and second fluxgate devices are applied to a magnetic field by the first and second driving currents and an externally applied magnetic field. A first magnetic fluxgate sensor unit including a first driving/detecting unit configured to detect the first orientation information by receiving the first and second pickup voltages induced by the respective,
The second magnetic sensor unit includes a third fluxgate device configured to detect an external magnetic field component in at least a third direction, a fourth fluxgate device configured to detect an external magnetic field component in a fourth direction, and at least the third and fourth fluxes. The third and fourth driving currents required for driving the gate element are applied, respectively, and the third and fourth magnetic fields induced by the third and fourth driving currents and the externally applied magnetic fields are induced from the third and fourth fluxgate elements. 4 It is a second magnetic fluxgate sensor unit including a second driving/detecting unit configured to receive each pickup voltage and detect the second orientation information,
The first direction is an arbitrary direction substantially parallel to the plane of the first body part, the second direction is a substantially normal direction to the plane of the first body part, and the third direction is the plane of the second body part The apparatus for measuring an angle between two bodies of a foldable device, characterized in that it is a substantially parallel arbitrary direction, and the fourth direction is a substantially normal direction to a plane of the second body part. The method of claim 4, wherein each of the first to fourth fluxgate elements is formed in a structure in which a driving coil and a pickup coil are respectively wound around a magnetic body,
Each of the first driving/detecting units is configured by the magnetization reversal characteristics of the magnetic bodies of the first and second fluxgate devices in each cycle while applying an AC driving current to the driving coils of the first and second fluxgate devices. The first azimuth information is respectively calculated using the degree to which each voltage peak of the generated first and second pickup voltages is shifted by the strength of an external magnetic field applied to the pickup coils of the first and second fluxgate elements, respectively. Is configured to produce,
The second driving/detecting unit is configured for each period while applying an AC driving current to the driving coils of the third and fourth fluxgate devices, respectively, by magnetization reversal characteristics of the magnetic bodies of the third and fourth fluxgate devices. The second azimuth information is respectively calculated using a degree in which each voltage peak of the generated third and fourth pickup voltages is shifted by the strength of an external magnetic field applied to the pickup coils of the first and second fluxgate elements, respectively. An apparatus for measuring an angle between two body parts of a foldable device, characterized in that it is configured to calculate. The method of claim 1, further comprising first and second interface units provided on the first body and the second body, respectively, and configured to provide an interfacing function with a user,
The control unit is configured to control the first and second interface units to operate as one integrated interface unit or separate independent interface units according to the calculated size of the interposition angle. A device for measuring the angle between negative. The method of claim 4, wherein each of the first and second magnetic fluxgate sensor units stores an origin offset size obtained in advance of each fluxgate device, and each fluxgate device stored when the first and second orientation information is detected. It is configured to apply the origin offset size of each of the fluxgate devices, wherein the origin offset size of each fluxgate device is the voltage peak when no external magnetic field is applied from the start of one period of the pickup voltage in the pickup voltage profile of the fluxgate device. An apparatus for measuring an angle between two bodies of a foldable device, characterized in that it is the time difference between the time of occurrence or the intensity of an external magnetic field equivalent thereto. The method of claim 4, wherein the control unit stores a pre-obtained origin offset size of each of the fluxgate elements of the first and second magnetic fluxgate sensor units, and between the first body and the second body. When calculating the angle, each fluxgate element is configured to apply an origin offset size for each fluxgate element to the first azimuth information and the second azimuth information provided from the first and second magnetic fluxgate sensor units, respectively, wherein the respective fluxgate elements The origin offset size of is characterized by the time difference from the start of one period of pickup voltage to the occurrence of voltage peak when no external magnetic field is applied in the pickup voltage profile of the corresponding fluxgate element, or the strength of the external magnetic field equivalent thereto. A device for measuring the angle between two bodies of a foldable device. The foldable device of claim 1, wherein the foldable device is reversibly moved from a state in which the first body part and the second body part are joined by a hinge axis and folded to overlap each other to an unfolded state to form the same plane, and the second body An apparatus for measuring an angle between two body parts of a foldable device, characterized in that it is a foldable communication device further comprising a display unit disposed on one surface of the first and second members. A first magnetic sensor unit installed on the first body of the foldable device detects the magnitude of an external magnetic field applied to it to generate first orientation information representing the direction in which the first body is directed, and the first body unit A second magnetic sensor unit installed in the second body portion of the foldable device, coupled to be foldable, detects the magnitude of the external magnetic field applied to itself, and provides second orientation information representing the direction in which the second body portion is directed. Generating first and second orientation information; And
The control unit uses the first orientation information and the second orientation information provided from the first and second magnetic sensor parts, and the first body part and the first body part around a folding axis between the first body part and the second body part. And a step of calculating an angle between the second body parts and calculating an angle between the two body parts of the foldable device. The angle between two bodies of a foldable device according to claim 10, further comprising the step of performing, by the control unit, a predetermined operation control or processing of the foldable device according to the calculated size of the angle between the two bodies of the foldable device. How to measure. The method of claim 10, wherein in a three-dimensional coordinate system having a point on the folding axis as an origin, the first orientation information is determined by the magnitude of an external magnetic field component in at least the first direction and the second direction from the origin. Information that can be mapped to a first azimuth vector connecting a first point, and the second azimuth information connects a second point determined by the magnitude of the external magnetic field component in the third and fourth directions from the origin. Information that can be mapped to a second orientation vector, the first direction is an arbitrary direction substantially parallel to the plane of the first body, and the second direction is a substantially normal direction to the plane of the first body. , The third direction is an arbitrary direction substantially parallel to the plane of the second body part, and the fourth direction is a substantially normal direction to the plane of the second body part, between the two body parts of the foldable device. Each measurement method. The method of claim 12, wherein the first magnetic sensor unit comprises a first flux gate element configured to detect at least an external magnetic field component in the first direction, a second flux gate element configured to detect an external organ field component in the second direction, And a first magnetic fluxgate sensor unit including a first driving/detecting unit,
The second magnetic sensor unit at least the sensor comprises at least a third fluxgate element configured to detect an external magnetic field component in the third direction, a fourth fluxgate element configured to detect an external magnetic field component in the fourth direction, and a second drive / It is a second magnetic fluxgate sensor unit including a detection unit,
The step of generating the first orientation information is performed by the first driving/detecting unit and, under a condition in which an external magnetic field is applied, at least while passing an AC driving current to the driving coils of the first and second fluxgate elements, respectively. Detecting first and second pick-up voltages respectively induced in pick-up coils of the first and second fluxgate elements; Detecting a time point of occurrence of a first voltage peak from the profile of the first pick-up voltage and detecting a point of occurrence of a second voltage peak from the profile of the second pick-up voltage every period; And a first shift amount at the time of occurrence of the first voltage peak and a second amount of shift at the time of occurrence of the second voltage peak compared to a time point of occurrence of the voltage peak when the external magnetic field is not applied, as the first orientation information. Including the step of outputting,
The step of generating the second orientation information is performed by the second driving/detecting unit and, under a condition in which an external magnetic field is applied, at least while passing an AC driving current to the driving coils of the third and fourth fluxgate elements, respectively. Detecting third and fourth pick-up voltages respectively induced in pick-up coils of the third and fourth fluxgate elements; Detecting a point of occurrence of a third voltage peak from the profile of the third pickup voltage and detecting a point of occurrence of a fourth voltage peak from the profile of the fourth pickup voltage every period; And a third shift amount at the time when the third voltage peak occurs and a fourth shift amount at the time when the fourth voltage peak occurs compared to when the voltage peak occurs when the external magnetic field is not applied, as the second orientation information. A method of measuring an angle between two body parts of a foldable device, comprising the step of outputting. The method of claim 13, wherein the k-th voltage peak generation point (where k=1, 2, 3, 4) is based on a value representing the magnitudes of voltages in an initial predetermined section in the k-th pickup voltage profile of the current period. It is calculated as a voltage and a k-th reference voltage obtained by adding a gap voltage of a predetermined size to the base voltage is calculated, and a time point at which a voltage value in the profile of the k-th pickup voltage of the current period is equal to the magnitude of the k-th reference voltage The method of measuring an angle between two body parts of a foldable device, characterized in that it is determined by a method that is determined as the time when the k-th voltage peak occurs. The two body parts of the foldable device of claim 13, further comprising performing calibration for correcting a measurement error of each of the first and second magnetic fluxgate sensor units in an initial state. How to measure the angle between them. The method of claim 15, wherein the performing of the calibration comprises: calculating the first and second origin offset sizes of the first and second fluxgate elements of the first magnetic fluxgate sensor unit and storing the first and second origin offset sizes in the data storage unit. ; Calculating third and fourth origin offset sizes of the third and fourth fluxgate elements of the second magnetic fluxgate sensor unit and storing them in the data storage unit; And when calculating an angle between the first body part and the second body part using the first and second azimuth information, applying the first to fourth origin offset sizes stored in the data storage And calibrating an origin offset of each of the first and second magnetic fluxgate sensor units. 15. A method of measuring an angle between two body parts of a foldable device, comprising: calibrating an origin offset of each of the first and second magnetic fluxgate sensor units. The method of claim 16, wherein the'calibrating the origin offset' comprises: applying the first and second origin offset sizes when the first magnetic fluxgate sensor unit calculates the first orientation information; And applying the third and fourth origin offset sizes when calculating the second azimuth information by the second magnetic fluxgate sensor unit, further comprising: measuring an angle between two body parts of a foldable device. Way. The method of claim 16, wherein the'calibrating the origin offset' comprises the first to fourth origin offsets in the first and second orientation information provided from the first and second magnetic fluxgate sensor units in the control unit. The method of measuring an angle between two body parts of a foldable device, further comprising the step of calculating the angle by applying a size. The method of claim 16, wherein the first to fourth origin offset sizes are, while the foldable device rotates 360 degrees while being positioned parallel to each of at least two planes of an xy plane, a yz plane, and a zx plane. Measuring a voltage peak occurrence time point in the pickup voltage profile of each of the first and second fluxgate elements of the first and second magnetic fluxgate sensor units, respectively, and obtaining a change trajectory of the voltage peak occurrence time point in a corresponding plane; The maximum value (Xmax) and minimum value (Xmin) in the x-axis direction, the maximum value (Ymax) and the minimum value (Ymin) in the y-axis direction, and the maximum value in the z-axis direction at the change trajectory at the point of occurrence of the voltage peak in each plane Obtaining (Zmax) and a minimum value (Zmin); And calculating the first to fourth origin offset sizes (X_offset, Y_offset, Z_offset) of each of the first and second fluxgate elements of each of the first and second magnetic fluxgate sensor units using the following equation. Method for measuring an angle between two body parts of a foldable device, characterized in that obtained through.
X_offset = (Xmax + Xmin)/2
Y_offset = (Ymax + Ymin)/2
Z_offset = (Zmax + Zmin)/2 The method of claim 15, wherein the performing of the calibration comprises: measurement sensitivity in the x-axis direction, measurement sensitivity in the y-axis direction, and measurement in the z-axis direction of each of the first and second magnetic fluxgate sensor units. Determining the sensitivity; Obtaining a sensitivity gain for each of the measurement sensitivity in the x-axis, y-axis, and z-axis directions; And removing a deviation between the measurement sensitivity in the x-axis, y-axis, and z-axis directions by applying a sensitivity gain of the corresponding axis to each of the measurement sensitivity in the x-axis, y-axis, and z-axis directions,
The sensitivity gain is determined as a ratio between the difference between the maximum value and the minimum value of the magnetic field used in the calibration of the origin offset and the difference between the maximum value and the minimum value at the point of occurrence of the measured voltage peak. Each measurement method.

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