JP2010148131A - Magnetic sensor and state detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multifunction magnetic sensor of a current consumption reduced type and further to provide a method for detecting movement of various magnets, which could not be detected conventionally without using a plurality of magnetic sensors, through one magnetic sensor while using the magnetic sensor and a magnet. <P>SOLUTION: The magnetic sensor includes a magnetism detecting means and a signal processing circuit for outputting a binary digital signal in accordance with the level of a detecting signal. The magnetic sensor further includes: a first output terminal that is turned to high level when the detecting signal is smaller than a first threshold; and a second output terminal that is turned to high level when the detecting signal is smaller than a second threshold of which the code is different from that of the first threshold, and is turned to low level in the other case. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a magnetic sensor and a state detection method, for example, a low current consumption type magnetic sensor and a state used for detecting an open / close or a rotation state in an open / close or rotation switch used in a turnover type mobile phone. It relates to the detection method.

  Conventionally, in a clamshell type mobile phone, a magnetic sensor and a magnet are often used to detect opening and closing.

  FIG. 3 shows a conventional clamshell type mobile phone open / close detection mechanism. In this mobile phone, a first housing 111 having a display 114 and a sub-display 115 and a second housing 112 having a switch portion 116 are coupled via a hinge portion 113 so as to be freely opened and closed. By disposing the magnet 117 in the first housing 111 and disposing the magnetic sensor 118 at a position facing the magnet 117 in the second housing 112, the magnetic flux density of the magnetic sensor 118 portion is increased with the opening and closing of the mobile phone. Since it changes, it is possible to detect opening and closing of the mobile phone. The output characteristics of the magnetic sensor 118 are shown in Table 1 ((C) of FIG. 3).

  As shown in FIG. 3, opening / closing detection can be performed by providing a magnet in one housing and arranging a magnetic sensor in the other housing. An example of the characteristics of the magnetic sensor used is shown in FIG. This magnetic sensor is a normal Hall IC, and if the threshold Bop is exceeded by the magnetic flux density of the S pole, the output voltage becomes a low level and becomes a value lower than the threshold Brp or high by the magnetic flux density of the N pole. is there.

  However, with recent rapid evolution of mobile phones, mobile phones called turnover types other than simple clamshell type mobile phones have begun to be released (for example, P505iS manufactured by Panasonic Mobile Communications). Although details will be described later, this type of mobile phone can be opened and closed in the same manner as the clamshell type, and further, the first housing having the display and the sub-display centering on the hinge portion is the second housing having the switch portion. It can rotate on the same plane as the body. Therefore, the turnover style mobile phone can take four states, and the conventional pair of magnetic sensors and magnets cannot detect these four states.

  A device having a conventional slide mechanism is shown in FIG. This is the case, for example, when detecting the presence or absence of a lens cover of a digital camera. As the magnetic sensor 128, a magnetic sensor having the characteristics shown in FIG. 8 is used. A device having a first housing 121 and a second housing 122, and the second housing 122 is slidably held. In this example, the magnet 127 is magnetized in a direction perpendicular to the sliding direction. When closed, the south pole of the magnet 127 faces the magnetic sensor 128. Therefore, the output of the magnetic sensor 128 becomes a low level when closed. When opened, the magnet 127 does not exert a magnetic flux on the magnetic sensor 128, so the output of the magnetic sensor 128 is at a high level. Thus, the two states of opening and closing could be detected by using a pair of magnets and a magnetic sensor. The output characteristics are shown in Table 3 ((C) in FIG. 5).

  As described above, the advancement of electronic components and mobile phones has advanced, and mobile phones having various movements other than the type that simply opens and closes are now on the market. Needless to say, a low current consumption type magnetic sensor for detecting various movements as described above is also required.

  In addition, the inventors previously provided a magnetic detection means and a signal processing circuit for inputting a detection signal from the magnetic detection means and outputting a binary digital signal of a plurality of bits according to the level of the detection signal. An invention relating to a magnetic sensor is disclosed and disclosed in Patent Document 1.

JP 2003-262665 A

  In a battery-driven electronic device such as a cellular phone, a low current consumption type sensor is required. However, in the invention of Patent Document 1, a reduction in current consumption has not been studied.

  In addition to simply detecting opening and closing, it has become necessary to detect various moving mechanisms such as rotation and slide with a magnetic sensor.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a multi-function magnetic sensor of a low current consumption type, and further using the magnetic sensor and magnet, It is an object of the present invention to provide a method for detecting movements of various magnets, which could not be detected without using a plurality of magnetic sensors, with a single magnetic sensor.

  The invention according to claim 1 is an electronic device, and is coupled to the first housing, the first housing and the first housing through a hinge portion so as to be openable and closable, and the first surface faces in the closed state. In an electronic apparatus having a second housing that can selectively take a state in which the second surface is opposed to the second surface, a magnetic sensor is attached to the first housing, and the magnetic sensor includes a magnetic detection means. And a signal processing circuit that inputs a detection signal from the magnetic detection means and outputs a binary signal according to the level of the detection signal, wherein the signal processing circuit A first output terminal that is at a high level when it is smaller than the first threshold, and at a low level in other cases, and the detection signal is smaller than a second threshold that is different in polarity from the first threshold High level, and low level in other cases Output terminals, and the magnetizing direction coincides with the opening / closing direction of the electronic device so that the magnetic poles are positioned on the first surface and the second surface, and in the closed state, One magnet is attached to the second casing so as to face the magnetic sensor.

  Invention of Claim 2 is the state detection method in the electronic device of Claim 1, Comprising: Using the output of the said magnetic sensor, the rotation state or the non-rotation state in the open state of the said electronic device and the closed state of the said electronic device Any one of the above is detected.

  The invention of claim 3 is a device comprising a main body and a slide portion that slides relative to the main body by a slide mechanism, wherein either one of a magnetic sensor and one magnet is attached to the main body, The magnetic sensor is a magnetic sensor having a magnetic detection unit and a signal processing circuit that inputs a detection signal from the magnetic detection unit and outputs a binary signal according to the level of the detection signal. The circuit has a first output terminal that is at a high level when the detection signal is smaller than a first threshold value and is at a low level at other times, and a first output terminal having a polarity different from that of the first threshold value. A second output terminal that is at a high level when it is smaller than a threshold value of 2, and at a low level in other cases, the other is attached to the slide portion, and the second output terminal. By id portion slides relative to said body, characterized in that each magnetic pole of the magnet and its intermediate portion is disposed said magnetic sensor and said magnet so as to approach to the magnetic sensor.

  According to a fourth aspect of the present invention, there is provided a state detection method for a device according to the third aspect, wherein any one of the three slide positions of the slide portion is detected using the output of the magnetic sensor.

  The magnetic detection means is composed of, for example, a semiconductor thin film or a nutritive thin film. Specifically, various magnetic detection means such as a Hall element and a magnetoresistive effect element (MR element) can be applied.

  There is no particular limitation on the type of magnet, but various magnets such as ferrite, samarium-cobalt, and neody that are usually mass-produced are applicable. When used in a portable device or the like, it is essential to reduce the size of the components. Therefore, it is preferable to use a samarium-cobalt or neodymium magnet that generates a strong magnetic field even if it is small.

  The signal processing circuit can be constituted by, for example, a Schmitt trigger circuit that compares the detection signal of the magnetic detection means with a predetermined threshold value and outputs a low level if it is larger than the threshold value and a high level if it is smaller. Further, it is preferable that the threshold value is set to different values such as the first threshold value and the second threshold value so that the output of the signal processing circuit does not chatter.

  Further, intermittent drive operation may be performed in order to reduce current consumption. As an example, it is possible to set the sleep time to 50 msec and the awake time to 24 μsec. Since the current consumption can be reduced by the ratio between the sleep time and the awake time, the current consumption can be further reduced by changing this ratio to a desired value.

  Basically, clamshell type mobile phones and laptop computers are often left in a closed state. Therefore, when opening / closing detection is performed using a magnet and a magnetic sensor, the magnet and the magnetic sensor are mostly in a state of being close to each other, and a normal state is that the magnetic flux density of the magnetic sensor unit is greater than a certain threshold value. Since reducing the current consumption in this normal state is effective for power saving of the device, it is preferable to configure the magnetic sensor so that the output voltage becomes a low level when the magnet is approaching. If the output voltage is low, the current that flows naturally decreases, which is very effective in reducing the current consumption of the magnetic sensor.

  Further, by using the magnetic sensor of the present invention, it is possible to detect the movement of the magnet, which could not be detected without using a plurality of magnetic sensors in the past, with one magnetic sensor. Therefore, the use of the magnetic sensor of the present invention can be a very effective means in reducing the size of various devices.

  As described above, according to the present invention, a low current consumption type multifunctional magnetic sensor can be provided, and it is possible to cope with various applications conveniently.

  In addition, by using the magnetic sensor and the magnet, various detection mechanisms that could not be detected without using a plurality of magnetic sensors can be performed by one magnetic sensor and one magnet. It is possible to cope with the situation conveniently.

It is a figure which shows the block diagram which shows one Example of the magnetic sensor of this invention. It is the characteristic view which showed the output characteristic in one Example of the magnetic sensor of this invention. It is the schematic which shows the opening / closing detection mechanism of the conventional clamshell type mobile phone. It is the schematic which shows the opening-and-closing and rotation detection mechanism of the turnover style mobile phone in this invention. It is the schematic which shows the conventional slide detection mechanism. It is the schematic which shows an example of the slide detection mechanism in this invention. It is the schematic which shows another example of the slide detection mechanism in this invention. It is a characteristic view which showed the output characteristic of the conventional magnetic sensor.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of a magnetic sensor according to the present invention. FIG. 2 is a characteristic diagram showing output characteristics in one embodiment of the magnetic sensor of the present invention.
In FIG. 1, reference numeral 50 denotes magnetic detection means for outputting a detection signal in accordance with the strength of the magnet, and outputs detection signals having different polarities by bringing the N pole or S pole of the magnet close to each other. The detection signal from the magnetic detection means 50 is amplified by the amplifier 51 and input to the level discrimination circuit 52. The level determination circuit 52 includes, for example, two comparators, thereby converting the detection signal into a digital signal corresponding to the detection level and outputting the digital signal using the output terminal 1 and the output terminal 2.

  One of the two digital signals (comparator output 1) has a high level when the detection signal is smaller than the first threshold value, and has a low level in the other case, and the other (comparator output 2) has the first detection signal. The threshold value is low level when it is larger than the second threshold value having a different polarity, and is high level in other cases.

  In the characteristic example of FIG. 2, the output terminal 1 (Output 1: indicated by a dotted line) changes to a low level under a magnetic flux density of N pole and becomes larger than a certain threshold value, but below that threshold value or below the magnetic flux density of the S pole. So it remains high. On the contrary, the output terminal 2 (Output 2: indicated by a solid line) changes to a low level under a magnetic flux density of the S pole and becomes a low level when it becomes larger than a certain threshold value, but is at a high level below the threshold value or under a magnetic flux density of the N pole. It remains. The configuration is equivalent to having the characteristics shown in FIG. 8 for two outputs of the N pole and the S pole.

  In addition, the threshold (in which the output of the magnetic sensor does not chatter (the magnetic flux density is near the threshold and the output voltage fluctuates between the high level and the low level) does not occur) Bop1 and Bop2) and threshold values (Brp1 and Brp2) for changing from a low level to a high level may be set to different values. That is, it is preferable that Bop1 and Brp1 have different values, and Bop2 and Brp2 have different values. Such a circuit can be configured using a Schmitt trigger circuit.

  In addition, when using for the apparatus which needs miniaturization, such as a mobile telephone, naturally it is also necessary to miniaturize a magnet. Therefore, since a magnetic sensor whose output changes with a small magnetic flux density is required, the magnetic flux density (Bop1 and Bop2) at which the output voltage changes from a high level to a low level is, for example, 3 mT or less (both N pole and S pole). It is preferable.

  In addition, when used in battery-powered equipment, it is essential to reduce current consumption, so intermittent drive operation may be performed. As an example, it is possible to set the sleep time to 100 msec and the awake time to 24 μsec. Since the current consumption can be reduced in a manner that correlates with the ratio between the sleep time and the awake time, the current consumption can be further reduced by changing this ratio to a desired value.

  Next, using the magnetic sensor and magnet of the present invention shown in FIG. 1 according to an embodiment, a method of detecting movement of various magnets that could not be detected without using a plurality of conventional magnetic sensors with one magnetic sensor. explain.

A method for detecting both opening and closing and rotation using the magnetic sensor and the magnet of the present invention will be described.
FIG. 4 shows a mobile phone called a turnover type, which can be opened and closed in the same manner as the clamshell type, and further includes a first housing 11 having a display 14 and a sub-display 15 around a hinge portion 13. The second casing 12 having the switch unit 16 can be rotated on the same plane. Therefore, the turnover style mobile phone can take four states shown in FIG. Of these, the states (A) and (C) need to be detected in the same manner as in the past, and in addition, the state (B) is also convenient when using the camera function attached to the mobile phone. It needs to be detected.

  When using a conventional magnetic sensor having the characteristics shown in FIG. 8, one magnet and one magnetic sensor are required for detecting both states (A) and (B). It is common to use a total of two sensors. However, if the magnetic sensor of the present invention is used, both states can be detected even if only one magnet and one magnetic sensor are used.

  Specifically, a magnet 17 magnetized with NS in the opening / closing direction of the mobile phone is arranged in the first housing 11 and the magnetic sensor 18 of the present invention is placed at a position facing the magnet 17 of the second housing 12. May be arranged. By adopting the above configuration, in the state shown in (A), the magnetic flux density of the magnetic sensor 18 becomes N pole, and the output terminal 1 changes to a low level. In the state of (B), the magnetic flux density of the magnetic sensor 18 part becomes the S pole, and the output terminal 2 changes to the low level. In the state of (C), both the output terminals 1 and 2 remain at the high level. The output characteristics are shown in Table 2 ((E) of FIG. 4).

  However, both in the state of (A) and in the state of (B), that is, even when the first housing 11 is rotated and closed, both the first and second magnets 17 are arranged so as to face the magnetic sensor 18. The housing 11 and the second housing 12 are arranged. In order for the magnet 17 to face the magnetic sensor 18 even when the first casing 11 is rotated and closed, both the magnet 17 and the magnetic sensor 18 have the same distance from the hinge portion 13. In addition, it is preferably arranged on the center line of the housing.

  If the magnetic force generated by the magnet 17 is large, the magnet 17 and the magnetic sensor 18 may be able to detect both states even if they are not on the same rotational radius of the hinge portion 13. Needless to say, the margin of the circuit increases.

  In this embodiment, the magnet 17 is disposed in the first housing 11 and the magnetic sensor 18 is disposed in the second housing 12. However, the magnet 17 is disposed in the second housing 12 and the magnetic sensor 18 is disposed in the second housing 12. You may arrange | position to the 1st housing | casing 11. Also, the magnetizing direction (NS direction) of the magnet is not particularly limited.

  By using the magnetic sensor of the present invention, it is possible to detect movements that could not be detected without using a plurality of magnets and a magnetic sensor, using only one magnet and one magnetic sensor. This is very effective in reducing the size of the device.

A method of performing slide detection using the magnetic sensor and magnet of the present invention will be described.
The present embodiment shown in FIG. 6 is a device having a first housing 21 and a second housing 22, and the second housing 22 is slidably held. The magnet 27 is magnetized in a direction parallel to the sliding direction. When closed as shown in FIG. 6A, the N pole of the magnet 27 is arranged to face the magnetic sensor 28, and the output terminal 1 of the magnetic sensor 28 outputs a low level value. When the second housing 22 is slid, a portion that is an intermediate point between the N pole and the S pole of the magnet 28 faces the magnetic sensor 28 (open time 1 shown in FIG. 6B). Since no magnetic flux density is generated in the magnetic sensor 28, the output of the magnetic sensor 28 is at a high level for both terminals 1 and 2. Further, when the second housing 22 is slid to the open state (open time 2 shown in FIG. 6C), the S pole of the magnet 27 is in a positional relationship facing the magnetic sensor 28. 28 output terminals 2 change to a low level. That is, in this embodiment, it is possible to recognize three states including the intermediate point in addition to the two states of opening and closing the slide position. The output characteristics are shown in Table 4 ((D) in FIG. 6).

  In this embodiment, the magnet 27 is disposed in the second housing 22 and the magnetic sensor 28 is disposed in the first housing 21. However, the magnet 27 is disposed in the first housing 21 and the magnetic sensor 28 is disposed in the first housing 21. You may arrange | position to the 2nd housing | casing 22. Also, the magnetizing direction (NS direction) of the magnet is not particularly limited.

  In this embodiment, a magnet magnetized in the sliding direction is used. However, as shown in FIG. 7, even if the magnet 37 is magnetized with four poles in the direction perpendicular to the sliding direction, the same three-state detection is performed. Is possible.

  Needless to say, the more the number of poles that can be detected, the greater the number of states that can be detected.

  In addition, it goes without saying that a similar detection method is possible using magnets of various magnetization methods.

  In the present embodiment, an example in which the magnet 27 and the magnet 37 move on a substantially straight line is shown, but it is not necessary to move on a straight line, and it is naturally possible to move on a curved line. For example, three states can be detected in the same manner even when the magnet moves on an arc.

  By using the magnetic sensor of the present invention, detection of three states that could not be detected without using a plurality of magnets and a magnetic sensor can be detected using only one magnet and one magnetic sensor. Therefore, it is very effective in reducing the size of the device.

  The present invention relates to a magnetic sensor, and particularly detects slide, open / close, and rotation state in a slide detection used in a portable device, an open / close used in a turnover type mobile phone, or a rotary switch. It is suitable for.

11, 21, 31 First housing 12, 22, 32 Second housing 13 Hinge portion 14 Display 15 Sub display 16 Switch portion 17, 27, 37 Magnet 18, 28, 38 Magnetic sensor 50 Magnetic detection means (Hall) element)
51 Amplifier 52 Level discriminating circuit 53 Regulator 111, 121 First housing 112, 122 Second housing 113 Hinge portion 114 Display 115 Sub-display 116 Switch portion 117, 127 Magnet 118, 128 Magnetic sensor

Claims (4)

A first housing, and a state in which the first surface is opposed to the first housing in a closed state and a state in which the second surface is opposed are coupled to the first housing through a hinge portion so as to be rotatable. In an electronic device having a second housing that can be selectively taken,
A magnetic sensor is attached to the first housing, and the magnetic sensor inputs a magnetic detection means and a detection signal from the magnetic detection means, and outputs a binary signal according to the level of the detection signal. A first output terminal that is at a high level when the detection signal is smaller than a first threshold and is at a low level in other cases; and A second output terminal having a high level when the signal is smaller than a second threshold having a polarity different from that of the first threshold, and a low level in other cases.
One magnet is arranged so that the magnetization direction coincides with the opening / closing direction of the electronic device so that the magnetic poles are located on the first surface and the second surface, and facing the magnetic sensor in the closed state. An electronic apparatus attached to the second housing.   2. The state detection method for an electronic device according to claim 1, wherein the output of the magnetic sensor is used to detect either the open state of the electronic device and the rotation or non-rotation state of the electronic device in a closed state. The state detection method in the electronic device characterized by this. In an apparatus comprising a main body and a slide portion that slides relative to the main body by a slide mechanism, either one of a magnetic sensor and one magnet is attached to the main body, and the magnetic sensor includes magnetic detection means, and the magnetic detection A signal processing circuit for inputting a detection signal from the means and outputting a binary signal according to the level of the detection signal, wherein the signal processing circuit is configured such that the detection signal is less than a first threshold value. The first output terminal, which is at a low level in other cases, and at a low level in other cases, and at a high level when the detection signal is smaller than a second threshold having a polarity different from that of the first threshold, A second output terminal that is at a low level in other cases,
The magnetic sensor and the magnet are attached so that the other magnetic pole of the magnet and an intermediate portion thereof are close to the magnetic sensor by attaching the other to the slide portion and sliding the slide portion with respect to the main body. Equipment characterized by the arrangement.   4. The state detection method for an apparatus according to claim 3, wherein one of three slide positions of the slide portion is detected using an output of the magnetic sensor.

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