JPS63142289A - Electronic equipment with bearing sensor - Google Patents

Abstract

PURPOSE:To reduce the size of an equipment by arranging a flux gate type magnetic sensor along the inner circumferential surface of a case body, a battery in the annular magnetic core of the magnetic sensor and a magnetically shielding member between the magnetic sensor and the battery. CONSTITUTION:A back 9 is mounted on the rear of a watch case body 1. A band 6 and the back 9 are made of a non-magnetic material that is not affected by the detection of terrestrial magnetism. A reflection type liquid crystal cell 10 is arranged below a windshield glass in the body 1 and the cell 10 is supported by a support member 12 arranged on the inner circumferential surface of the body 1. The annular magnetic core 4 of a flux gate type magnetic sensor 30 for detecting a bearing is arranged along the inner circumferential surface of the support member 12. An exciting and detecting coil 18 is wound around the magnetic core 4. Magnetically shielding plates 20 and 21 are provided above the magnetic core 4 and on the inner circumference thereof, respectively, in order to avoid the effect of external magnetic field on the coil 18. A battery 5, held by a support case 23, is accommodated in the body 1. Thus, housing the sensor 30 to be built-in, the size of the equipment can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an electronic device equipped with an orientation sensor, and particularly to an arrangement structure within a case of a fluxgate type magnetic sensor.

[Conventional technology]

2. Description of the Related Art Electronic watches with a compass are conventionally known as small electronic devices equipped with a compass. This is not a device that tells you the direction electronically (it is a watch band with a magnet attached to it that tells you the direction in the direction the magnetic needle points, and since the magnet is separate from the watch itself, it is very bulky.

In response to this, the present applicant has proposed an electronic clock with a built-in Hall element as a method for electronically detecting the direction in Japanese Patent Application Laid-Open No. 126285, but the detection of geomagnetism by the Hall element has some sensitivity. There are some difficulties.

Incidentally, in recent years, a fluxgate type magnetic sensor has become known as a geomagnetic sensor that can detect geomagnetism electronically and has excellent sensitivity characteristics. (For example, Tokuko Sho 58-15
No. 723) [Problems to be Solved by the Invention] A fluxgate type magnetic sensor has an excitation coil and a detection coil wound around a ring-shaped magnetic core, and when an alternating pulse signal is supplied to the excitation coil, the magnetic sensor is connected in parallel with the detection coil. The geomagnetism is measured by detecting and smoothing the signal taken out from the connected capacitor and from the DC voltage value obtained, and its output is proportional to the cross-sectional area of the annular magnetic core. Therefore, in order to obtain a large output using this fluxgate type magnetic sensor, a magnetic core of a certain size and thickness is required. Due to the relationship with the component parts, it is difficult to arrange and downsize. On the other hand, in an orientation sensor using a fluxgate type magnetic sensor, in order to improve the followability of orientation instructions, it is necessary to shorten the cycle of the alternating pulse signal supplied to the excitation coil, which requires more power consumption. I need.

Additionally, orientation sensors using fluxgate magnetic sensors may display incorrect orientation unrelated to geomagnetism if there is a magnetic field that exceeds the geomagnetism due to the approach of a magnet, etc., or in places where geomagnetism cannot be detected, such as inside a tunnel. However, it is not possible to display the direction, but it is not reliable in use.

A first object of the present invention is to provide a compact electronic device with a direction sensor that includes a built-in fluxgate type magnetic sensor.

A second object of the present invention is to provide an electronic device with a direction sensor that consumes less power.

A third object of the present invention is to provide an electronic device with an orientation sensor that issues an incorrect orientation display alarm.

[Means for solving problems]

An electronic device with an orientation sensor according to the present invention includes a fluxgate type magnetic sensor comprising an annular magnetic core made of a high permeability material and an excitation coil and a detection coil wound around it, and an external magnetic field that cooperates with the magnetic sensor. An electronic device with an azimuth sensor, which comprises an integrated circuit including a home boundary detection circuit for detecting the azimuth and an arithmetic circuit for calculating the azimuth, a display device for displaying at least the azimuth, and a battery for power supply housed in a case body, The fluxgate type magnetic sensor is disposed along the inner peripheral surface of the case body, and the battery is disposed within the annular magnetic core of the magnetic sensor, and between the fluxgate type sensor and the battery. It is characterized by having a magnetic shielding member disposed at.

〔Example〕

In this embodiment, an electronic device with an azimuth sensor will be explained using an electronic watch with an azimuth sensor as an example.

FIG. 1 shows the external appearance of an electronic watch with an orientation sensor according to the present invention. As shown in FIG. Button 8A and time adjustment button 8B
and is provided.

A liquid crystal display device 6 as shown in FIG. A time display section 6a is provided, and a direction display section 6b consisting of a large number of segments is provided around the periphery.When the back cover of the watch case main body 1 is removed, as shown in Fig. 1(C).
As shown in the figure, the annular magnetic core 4 of the fluxgate type magnetic sensor 60 is arranged in the empty space 1C, and the power supply battery 5 is arranged inside the annular magnetic core 4.

A band 6 is removably attached to the watch case body 1. In order to attach the band, a concave portion 1a is formed in the watch case body 1, and a convex portion 6a is formed at the tip of the band B. (See Figure 2).

Next, the internal structure of the electronic timepiece according to the present invention will be explained with reference to FIG.

A windshield 7 is attached to the center of the front side of the watch case body 1, and an operation button 8 made of an elastic member is attached around the windshield 7. This operation button 8 is shown in Figure 1 (
This is the mode switching button 8A or the time adjustment button 8B shown in a).

On the other hand, a back cover 9 is detachably attached to the back side of the watch case body 1. The band 6 and back cover 9 are made of non-magnetic material such as plastic material so as not to affect detection of earth's magnetic field.

Now, inside the watch case body 1, a reflective liquid crystal cell 10 constituting the liquid crystal display device 6 is arranged immediately below the windshield 7, and a reflective plate 11 is arranged immediately below it. . The liquid crystal cell 10 is supported by a support member 12 arranged along the inner peripheral surface of the watch case body 1.

A circuit board 16 is fixed to the support member 12, and the circuit board 16 includes circuit elements 14 such as integrated circuits including a clock circuit and an arithmetic circuit for calculating an orientation based on the detection results of geomagnetism. The circuit element 14 is covered with a protective mold 15.

The liquid crystal cell 10 and the circuit board 16 are electrically connected by a connecting member 16 made of conductive rubber. circuit board 1
A switch pattern 17 is formed near the periphery of 6 (the part near the left end in the figure), and this switch pattern 17 is turned on and off by a switch contact 8a made of conductive rubber provided at the lower end of the operation button 8. .

Now, an annular magnetic core 4 of a fluxgate type magnetic sensor 60 for detecting orientation is arranged along the inner circumferential surface of the support member 12 (see FIG. 1(C)), and around this annular magnetic core 4. A coil 18 for excitation and detection is evenly wound, and the coil 18 is covered with a mold 19 to protect the entire coil 18. Magnetic shield plates 20 and 21 are provided on the upper side and inner peripheral side of the annular magnetic core 4 to avoid any influence on the external magnetic field 18. The magnetic shield plates 20, 21 are made of a shoulder magnetic permeability material such as permalloy.

The terminals of the excitation and detection coils 18 are connected to the circuit board 16.
It is electrically connected to the circuit element 14 via a circuit node 22 attached to the lower surface of the .

The battery 5 is supported by the support case 26 and the watch case body 1
stored inside. Note that 24 is ノ(tsuking).

FIG. 3 shows the basic circuit configuration of an electronic timepiece with an orientation sensor according to the present invention.

In the figure, 60 is a fluxgate type magnetic sensor that detects earth's magnetism, and an exciting coil 18a is attached around the annular magnetic core 4.
and the detection coil 18b are wound in a toroidal shape. The detection coil 18b is divided into an X-axis detection coil 18bx and a Y-axis detection coil 18by, which are arranged in a positional relationship that is perpendicular to each other, and each detection coil is arranged in two diametrically separated parts on the annular magnetic core 4. These two
The principle of geomagnetism detection by the fluxgate type magnetic sensor 30, in which the two parts are electrically connected in series, will be explained with reference to FIG.

If a magnetic field HIl due to earth's magnetism exists as shown in FIG. 5, the component Hgx where this magnetic field H8 intersects with the X-axis detection coil 18bx and the component Hay where it intersects with the Y-axis detection coil 18by are as shown in the following equation.

)(s, = H, CO5θ, Hs y = Hs sin
θThen, these respective magnetic components H8X and Hsy are applied to the terminals of capacitors cx and cy connected in parallel to the X-axis detection coil 18bx and Y-axis detection coil 18by by an excitation signal supplied to the excitation coil 18a. It is output as a signal pbx and a Y-axis component signal Pby.

The voltage levels of the component signals pbx and Pby of the earth's magnetic field are proportional to the magnitudes of the components Hax and Hsy of the magnetic field (s).

The clock circuit 40 has a normal circuit configuration, and includes a reference oscillation circuit 41 consisting of a crystal oscillator, etc., and a second signal P necessary for displaying time by dividing the reference signal output from the reference oscillation circuit 41.
t, a timing signal generating circuit 42 that generates timing signals P, , P, and f, a timing circuit 46 that generates a minute signal and an hour signal based on the seconds signal Pt, and a timing signal generating circuit 46 that generates a minute signal and an hour signal based on the seconds signal Pt; The time display driver 44 outputs a time display signal based on , minute, and hour signals.

The direction meter circuit 50 for displaying direction is connected to the clock circuit 40.
The fluxgate type magnetic sensor 6
A rectangular pulse generation circuit 51 that generates a rectangular excitation pulse signal Pk for exciting 0, and a geomagnetic X-axis component signal Pbx extracted through a capacitor Cx connected in parallel with the X-axis detection coil 18bX. A magnetic field detection circuit 52, an A/D conversion circuit 56 that A/D converts the output signals P and x of the magnetic field detection circuit 52, and a Y-axis detection coil 18b.
A magnetic field detection circuit 54 detects a Y-axis component signal PbA of the earth's magnetism taken out via a capacitor CA connected in parallel with y, and output signals P and A of the magnetic field detection circuit 54 are connected to an A/D converter.
An A/D conversion circuit 55 that converts the data, an arithmetic circuit 56 that calculates the direction from the detected geomagnetic X-axis component signal Pbx and Y-axis component signal PbA at the cycle of the timing signal P2, and outputs the direction data, and the direction data Dh. and a direction display driver 57 that outputs a direction display signal Dd based on the direction.

The magnetic field detection circuit 52 includes a detection circuit that detects the earth's magnetic X-axis component signal Pbx and a smoothing circuit that smoothes the detected output, and the magnetic field detection circuit 54 has the same configuration.

FIG. 4 shows the timing signal Pi, "2-fl" generated by the timing signal generation circuit 42, the rectangular excitation pulse signal Pks generated from the compass circuit 50, the earth's magnetic X-axis component signal Pbx, and the field detection circuit 52. It shows the time relationship between the output signal P and the process.

The liquid crystal display device 6 has a time display section 6a that displays the date, day of the week, and time based on the time display signal S output from the clock circuit 40, and a direction display signal output from the compass circuit 50.]
) d, and an azimuth display section 6b that displays the azimuth based on d.

Next, the operation of the electronic timepiece with an orientation sensor having the above basic circuit configuration will be briefly explained with reference to FIG.

The time display is the same as in the case of a normal electronic watch.The clock circuit 46 generates a calendar signal in addition to the minute signal and hour signal based on the second signal Pt, which is frequency-divided and generated by the timing signal generation circuit 42. The display driver 44 generates a time display signal St based on these signals. The date, day of the week, and time according to the time display signal St are displayed on the time display section 3a of the liquid crystal display device B.

For displaying the direction, first, the rectangular pulse generation circuit 51 of the direction meter circuit 50 is triggered at the cycle of the timing signal P to generate a rectangular excitation pulse signal Pk, and this rectangular excitation pulse signal Pk is sent to the fluxgate type magnetic sensor 30. It is supplied to the excitation coil 18a. As a result, the X-axis component signal Pbx and the Y-axis component signal Pby of the earth's magnetism as shown in FIG. 4 are obtained from the X-axis detection coil 18bX and the Y-axis detection coil 18bY. (Only Pbx is illustrated in FIG. 4.) The magnetic field detection circuits 52 and 54 detect and smooth these geomagnetic component signals Pbx and Pba to obtain peak values v,
1 signal P,! and outputs P and y. Output signal P,
X, P, and A are A/D converted by A/D conversion circuits 56 and 55 and sent to an arithmetic circuit 56. (Only P and ! are illustrated in FIG. 4.) The arithmetic circuit 56 calculates the orientation θ as follows at the cycle of the timing signal P2, and outputs it as orientation data fi D h.

tanθ=:H, sinθ/H, cosθ=Ppy/
The Ppx direction display driver 57 outputs a direction display signal Dd based on the direction data Dh output from the arithmetic circuit 56, and the direction is displayed on the direction display section 6b of the liquid crystal display device 6.

FIG. 6 shows a first embodiment of an electronic timepiece with an orientation sensor according to the present invention, which aims to reduce power consumption. Only the main parts are shown in the figure, and the same reference numerals as in FIG. 3 indicate the same components. Show parts.

In this embodiment, the magnetic field detection circuit 52 is composed of a timer circuit 52a and a sample and hold circuit 52b, and the magnetic field detection circuit 54 is also composed of a timer circuit and a sample and hold circuit (not shown). However, the magnetic field detection circuits 52 and 54 have completely different circuit configurations and circuit operations (
Since they are the same, only the magnetic field detection circuit 52 will be described below.

Details of the timer circuit 52a and sample hold circuit 52b that constitute the magnetic field detection circuit 52 are shown in FIG. As can be seen from the figure, the timer circuit 52a is activated when the rectangular excitation pulse signal Pk from the rectangular pulse generation circuit 51 falls (to).
A D flip-flop 1 outputs a sample control signal P for a certain period of time (time corresponding to 1/2 of the pulse width τ) from
Consists of 00. In addition, the sample hold circuit 52
b includes a buffer amplifier 101 that inputs the geomagnetic X-axis component signal Pbx output from the detection coil of the fluxgate magnetic sensor 60 to a non-inverting terminal, and a timer circuit 52a.
The transmission gate 102 is turned on and off by the sample control signal P6 outputted by the capacitor 10.
6, a buffer amplifier 104 having a function of preventing discharge of a capacitor 106, and an inverter 105 connected to a transmission gate 102.

Note that the buffer amplifier 101 or 104 may have an amplification function.

The operation of the magnetic field detection circuit 52 will be explained with reference to the timing chart shown in FIG.

When the timer circuit 52a receives the rectangular excitation pulse signal Pk, the D flip-flop 100 operates at the falling edge of the rectangular excitation pulse signal Pk. The data H applied to the D terminal is read in and output from the Q terminal as a sample control signal P8.

This sample control signal P is a D flip-flop 100.
The rising edge t of the timing signal f, which is input to the reset terminal R of .

Since it is reset to L, the pulse width becomes τ/2 (τ is the pulse width of the rectangular excitation pulse signal Pk).

On the other hand, at this time, the sample and hold circuit 52b is supplied with the geomagnetic X-axis component signal Pbx as shown in FIG. The X-axis component signal Pbx is passed through as is to charge the capacitor 103.

Since the transmission gate 102 is closed at time tl when the sample control signal P becomes L level, the voltage value of the capacitor 106 becomes the output signal P of the magnetic field detection circuit 52. The geomagnetic X-axis component signal Pbx then attenuates, but the output signal P of the magnetic field detection circuit 52 remains the geomagnetic X-axis component signal Pbx as shown in FIG. 8 until the next rectangular excitation pulse signal Pk is output. is held at the peak value v, x. This peak value ■, x is the external magnetic field H'', and the second X-axis component H
, is proportional to x.

The circuit operation of the other magnetic field detection circuit 54 is also exactly the same, and the magnetic field detection circuit 54 outputs a geomagnetic Y-axis component signal Pb.
The peak value Vpy of y continues to be output.

In the arithmetic circuit 56, these magnetic field detection circuits 52 and 54
The direction is calculated using the peak values of the output signals Pp, P, and A and V.

px py In this way, by supplying the rectangular excitation pulse signal Pk once to the excitation coil 18a of the fluxgate type magnetic sensor 60, the current geomagnetism detection signal can be maintained and the direction can be calculated, reducing power consumption. Less is needed.

FIG. 9 shows a second embodiment of the electronic timepiece with an orientation sensor according to the present invention, which also aims to reduce power consumption, and the same reference numerals as in FIG. 6 indicate the same components.

In this embodiment, the magnetic field detection circuits 52 and 54 are constructed of peak hold circuits as shown in FIG.

The peak hold circuit 52C receives the geomagnetic X-axis component signal Pb.
A buffer amplifier 200 that inputs x to a non-inverting terminal, converts the impedance and outputs it as is, and a diode 20.
1, a switch 202 composed of an N-channel MO8 and turned on when receiving a rectangular dynamic pulse signal Pk, a capacitor 206, and a buffer amplifier 204 having a function of preventing discharge of the capacitor 203.

Note that the buffer amplifier 200 or 204 may be provided with an amplification function.

Next, the operation of the magnetic field detection circuit will be explained with reference to the timing chart shown in FIG.

When the peak hold circuit 52C receives the rectangular support pulse signal Pk, the switch 202 is turned on, so the capacitor 2
06 is short-circuited and becomes the initial state.

t at the falling edge of the rectangular excitation pulse signal Pk. Since the switch 202 is turned off, the geomagnetic X-axis component signal Pb x input to the buffer amplifier 200 photoelectrically charges the capacitor 206 via the buffer amplifier 200 and the diode 201 . The terminal voltage of the capacitor 206 rises as the X-axis component signal Pbx rises, but when it starts to fall after passing its peak value Vbl, it is blocked by the diode 201, so the capacitor 206 holds the peak value Vbl of Pbx. . This peak value vbt becomes the output of the buffer amplifier 204, that is, the output signals P and X of the peak hold circuit 52C.

The same applies to the 51 magnetic field detection circuits 54 shown in FIG. 9, so these output signals P, x (=Vb+)
The direction can be calculated by an arithmetic circuit using the direction Ppy (=V+) 2 ) and the direction. In this embodiment as well, as in the embodiment shown in FIG. 6, the direction can be calculated by supplying the rectangular excitation pulse signal Pk once, so that power consumption can be reduced.

FIG. 12 shows a third embodiment of an electronic timepiece with an orientation sensor according to the present invention having a false orientation alarm function, in which the same reference numerals as in FIG. 3 indicate the same components.

This embodiment is based on the direction meter circuit 50 of the basic circuit shown in FIG.
An erroneous orientation determination circuit 70 is provided inside the sensor to determine whether the detected geomagnetic level is within a predetermined range.

The incorrect orientation determination circuit 70 is a first orientation level determination circuit 70 that determines that the detected geomagnetism is higher than a predetermined level.
a, and a second azimuth level determination circuit 70b that determines whether the detected geomagnetism is lower than a predetermined level, and outputs an error azimuth signal when the detected geomagnetism level is outside the predetermined range.

The first azimuth level determination circuit 70a is a digital signal that compares the A/D converted values of the output signals P and x of the magnetic field detection circuit 52 and the magnetic level M with a reference memory 80 that stores a magnetic level M1 that is extremely larger than the earth's magnetism. A comparison circuit 81 compares the output signal P of the magnetic field detection circuit 54 with the A/D conversion conversion of y and the magnetic level M, and a digital comparison circuit 82 calculates the logical sum of the outputs of the two comparison circuits 81 and 82. OR circuit 8
6, and a second azimuth level determination circuit 7.
0b indicates the output signal P of the reference memory 90 storing the magnetic level M2, which is extremely smaller than the earth's magnetism, and the magnetic field detection circuit 52.
, a digital comparison circuit 91 that compares the A/D conversion value of , and two comparison circuits 91.92
and an AND circuit 93 that performs the logical product of the outputs of.

Reference numeral 94 is an OR circuit which takes the logical sum of the outputs of the first azimuth level determination circuit 70a and the second azimuth level determination circuit 70b.

The X-axis component H of the earth's magnetism detected by the fluxgate type magnetic sensor 60,! When the Y-axis component H3y is inputted to the azimuth level determination circuits 70a and 70b, each comparator circuit compares it with the magnetic levels M, , M2 stored in the reference memory, and one of the components is determined to be the magnetic level. When the magnetic level is higher than M1, H is output from the first azimuth level determination circuit 70a, or when any component is lower than the magnetic level M2, the second azimuth level determination circuit 70a outputs H.
H is output from 0b. The former case is when a magnet comes close to an electronic watch, and the latter case is when it is detected inside a tunnel.

In any case, when H is output as a wrong direction signal from the first direction level judgment circuit 70a or the second direction level judgment circuit 70b, it is sent to the direction display driver 57, and a wrong direction alarm is displayed on the direction display section 3b. . The misdirection alarm may be issued by erasing or blinking the previously displayed direction pattern, or by separately lighting a misdirection mark. Instead of using such a liquid crystal display device 6, a warning sound such as a buzzer may be emitted.

Such a false orientation warning can improve the reliability of the orientation sensor.

FIG. 13 shows the second example of the electronic timepiece with an orientation sensor according to the present invention.
This is an example showing another configuration different from the example shown in the figure. Components in the figure that are the same as those in FIG. 2 are designated by the same reference numerals.

In this embodiment, a touch switch is used in place of the operation button of the embodiment shown in FIG. 2, and the annular magnetic core 4 of the fluxgate type magnetic sensor has a flat shape. The touch switch 25 consists of conductive electrodes formed continuously on the upper and lower surfaces of the windshield 7 using a technique such as vapor deposition, and when a person touches a part of this electrode with a finger, the conductive connecting member 16 is connected. A switch signal is sent to the circuit board 16 via the circuit board 16, and the above-described mode switching and time adjustment can be performed.

〔Effect of the invention〕

As described in detail above, according to the present invention, a fluxgate type magnetic sensor can be built into a small electronic device, and a small electronic device with a small azimuth sensor can be provided.

[Brief explanation of the drawing]

FIG. 1 shows an electronic timepiece with a direction sensor as an example of an electronic device with a direction sensor according to the present invention, in which (a) is a front external view of a completed electronic timepiece, and (b) is a display device and annular shape of the electronic timepiece. Figure 2 is a diagram of the positional relationship of the magnetic cores. (C) is a back view showing the arrangement of the annular magnetic core and battery with the back cover of the electronic watch removed. Figure 2 is the diagram of the electronic watch with orientation sensor shown in Figure 1. 3 is a basic circuit configuration diagram of an electronic timepiece with an orientation sensor as an embodiment of the present invention; FIG. 4 is a timing chart of signals in each part of the basic circuit shown in FIG. 3; Figure 5 is a diagram explaining the principle of azimuth calculation using a fluxgate type magnetic sensor, Figure 6 is a circuit diagram mainly showing the first embodiment of the magnetic field detection circuit of the basic circuit shown in Figure 3, and Figure 7 is Figure 6 is a line diagram showing the detailed configuration of the magnetic field detection circuit shown in Figure 8. Figure 8 is a timing chart of signals in each part of the circuit shown in Figure 7. Figure 9 is the basic circuit shown in Figure 3. A circuit diagram mainly showing the second embodiment of the magnetic field detection circuit, FIG. 10 is a circuit diagram showing the detailed configuration of the magnetic field detection circuit shown in FIG. 9, and FIG. 11 is a circuit diagram showing each part of the circuit shown in FIG. 10. 12 is a circuit diagram showing the detailed configuration of the azimuth meter part of the basic circuit shown in FIG. FIG. 7 is a partial cross-sectional view showing another example of sensor arrangement. 6...Fluxgate type magnetic sensor 1st
Figure (a) 'tK 1~98 ki to

Claims (1)

[Claims] A fluxgate type magnetic sensor comprising an annular magnetic core made of a high magnetic permeability material and an excitation coil and a detection coil wound around it;
An integrated circuit including a magnetic field detection circuit that works with the fluxgate type magnetic sensor to detect an external magnetic field and an arithmetic circuit that calculates the orientation, a display device that displays at least the orientation, and a battery for power supply are installed inside the case body. In the electronic device with an orientation sensor housed in the case body, the fluxgate type magnetic sensor is disposed along the inner circumferential surface of the case body,
An electronic device with an orientation sensor, characterized in that the battery is disposed within the annular magnetic core of the fluxgate magnetic sensor, and a magnetic shield member is disposed between the fluxgate magnetic sensor and the battery.