JP4612281B2 - Position detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a position detection device that detects the movement or inclination of an object, and more particularly to a position detection device that uses the position detection device and is used as input means for a personal computer, a mobile phone, or the like. More specifically, the present invention relates to a magnetic detection type position detection device that performs coordinate detection by detecting a change in the surrounding magnetic field due to movement of a magnet.
[0002]
Devices that detect the movement, tilt, or movement angle of an object with a magnet, a magnetic material, and a magnetic sensor are known. In addition, optical, pressure-sensitive, variable resistance, and magnetic detection methods have been put to practical use as pointing detection methods (joysticks, trackballs, etc.) for personal computers (including amusement and simulation computers). However, in recent years, magnetic detection methods that are easy to miniaturize, have no contact, and have a long life have become prominent.
[0003]
[Prior art]
FIG. 8 is a block diagram showing a magnetic detection circuit of a conventional magnetic detection type pointing device. The detection unit 31 includes four Hall elements 41 arranged symmetrically along the X axis and the Y axis. Thus, the differential amplifier 32 differentially amplifies the output signals of the Hall elements 41 in the X-axis direction and the Y-axis direction due to the movement of the magnet disposed above the Hall element 41, and the output signal ( Analog value) is converted into a digital value by the A / D converter 33, and the output signal (voltage) is converted into an X coordinate value and a Y coordinate value by the detection control unit 34, and this is output via the output control unit 35. (For example, refer patent document 1).
[0004]
As a specific example of the above-described support mechanism that enables the magnet to move, as shown in FIG. 9, a magnet 42 is supported on one end of a coil spring 44 and a magnetic sensor 41 disposed on a substrate on which the coil spring 44 is installed. Therefore, a configuration is proposed in which the movement of the magnet 42 is detected by the magnetic sensor 41.
[0005]
[Patent Document 1]
Japanese Patent Laid-Open No. 10-20999 [0006]
[Problems to be solved by the invention]
However, the position detection device and the magnetic detection type pointing device described above have three problems as described below. First, there is a problem that the magnet strength, the variation in the sensitivity of the magnetic sensor, and the drift due to the temperature characteristics of the magnetic sensor affect the output signal with respect to the moving amount and inclination of the magnet. Next, as a second problem, if the distance between two magnetic sensors on the same axis changes or the distance between the magnetic sensor and the magnet shifts, the output signal is similarly affected. is there. Furthermore, as a third problem, when the magnet is located between the magnetic sensors, the movement amount and the output signal increase relatively monotonously, but when the magnet moves greatly beyond the range of the magnetic sensor. Has a problem that the distance between the magnetic sensors cannot be increased because the difference signal gradually decreases for a while.
[0007]
The present invention has been made in view of such problems, and an object of the present invention is to provide a position detection device that suppresses the influence on variation in characteristics of magnets and magnetic sensors and assembly accuracy.
[0008]
It is another object of the present invention to provide a position detecting device that can be miniaturized so that the range of monotonous increase in signal with respect to the amount of movement of the magnet becomes large.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is characterized in that the invention according to claim 1 includes four magnetic sensors arranged two each along the X axis and the Y axis, and the four magnetic sensors. A position detecting device including a magnet disposed in the vicinity of the center so as to be movable or tiltable , wherein the range of a monotonically increasing output signal with respect to the amount of movement of the magnet is increased on the X axis. wherein said output value obtained by dividing the difference signal of the two magnetic sensors in the sum signal of the two magnetic sensors on the X axis, a difference signal of the two magnetic sensors on the Y axis on the Y axis The output value divided by the sum signal of the two magnetic sensors is output as a position signal, and the output value increases over a predetermined range with respect to the moving distance of the magnet .
[0010]
According to a second aspect of the present invention, there is provided the magnetic sensor according to the first aspect of the present invention, wherein four magnetic sensors are disposed along the X-axis and the Y-axis, and two magnetic sensors are disposed near the center of the four magnetic sensors. A magnet that is arranged so as to be movable or tiltable. A value obtained by dividing a difference signal of two magnetic sensors on the X axis by a sum signal of the four magnetic sensors, and two magnetic sensors on the Y axis. A value obtained by dividing the difference signal by the sum signal of the four magnetic sensors is output as a position signal .
[0013]
As the magnetic sensor, various magnetic sensors such as a Hall element, Hall IC, magnetoresistive effect element (MR element), magnetoresistive effect IC (MRIC), and reed switch can be applied, and an analog output type pointing device. For this, an analog output type magnetic sensor is desirable, and a digital output type magnetic sensor is desirable for a digital output type pointing device.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram for explaining an embodiment of a pointing device according to the present invention. In the figure, reference numeral 1 denotes a magnetic sensor, 2 denotes a magnet, 3 denotes silicone resin as an elastic member, 4 denotes a mounting substrate, 5 Is a pressing member, 6 is a switch, 7 is a space, and 7a is a notch. As described above, two magnetic sensors 1 are arranged on the mounting substrate 4 symmetrically along the X axis and the Y axis. The magnet 2 is NS magnetized in the vertical direction.
[0015]
When the silicone resin 3 is moved so as to be shifted in a plane parallel to the mounting substrate 4, the silicone resin 3 swings with the end of the notch 7a as a fulcrum, and the magnet 2 similarly swings accordingly. Move.
[0016]
As described above, the pointing device of the present invention includes a plurality of magnetic sensors 1 provided on the mounting substrate 4 and an elastic portion 7 provided on the mounting substrate 4 and capable of swinging in any direction. A magnetic density change caused by sliding of the magnet 2 due to elastic deformation of the elastic member 3 is detected by a plurality of magnetic sensors 1 and includes coordinate information or vector information. Is configured to input.
[0017]
Further, the magnet 2 is swingable in the horizontal direction as described above, and can be displaced in the vertical direction with respect to the mounting substrate 4, and is free to move in the horizontal and vertical directions with respect to the mounting substrate 4. Have a degree.
[0018]
Further, the elastic member 3 has a bent portion, and a notch portion 7a is formed in the bent portion to make the magnet 2 swingable effectively.
Further, a switch 6 is disposed on the mounting substrate 4 in the space portion 7, and the pointing device has a switch function.
[0019]
There is no particular limitation on the type of switch, but any switch such as a push button switch may be used. However, it is easy to confirm that the switch has been pressed (it has a feeling of clicking), and it automatically returns after the switch is pressed. A switch for confirming an object using physical contact with the object such as a tactile switch, a tact switch, a touch switch, or a stroke switch is suitable.
[0020]
Also, the magnet 2 is not particularly limited in kind, but various magnets such as ferrite, samarium-cobalt, and neody that are usually mass-produced are applicable. In order to reduce the size of the pointing device, it is essential to reduce the size of the magnet. Therefore, a samarium-cobalt type or neody type magnet that generates a strong magnetic field even if it is small is preferable.
[0021]
Further, the elastic member is not particularly limited in kind, but a silicone resin currently used for various applications is preferable.
[0022]
Further, the pressing member 5 is preferably formed of a material having a rigid property so that the magnet 2 is not shaken or dented when pressed with a fingertip. In particular, a non-magnetic material is preferable in order to reduce the strength of the magnetic field leaking to the outside. For example, it is produced by cutting polycarbonate, resin such as modified polyferylene ether or polystyrene, metal such as magnesium alloy or aluminum alloy formed by press working or the like.
[0023]
With this configuration, when the pressing member 5 is pressed from the right side to the left direction, the pressing member 5 is oscillated and displaced leftward with the coupling end portion of the elastic member 3 and the mounting substrate 4 as a fulcrum. Is pushed in the right direction from the left side, it is oscillated and displaced in the right direction with the coupling end of the elastic member 3 and the mounting substrate 4 as a fulcrum. In this manner, the magnet 2 provided on the elastic member 3 can swing left and right. This operation can be performed by the belly portion of the index finger or the belly portion of the thumb. In this case, it is desirable that the surface of the pressing member 5 be any one of a rough surface, a concave surface, a convex surface, a convex quadrangular pyramid, and a concave quadrangular pyramid in consideration of adhesion with a finger. The shape of the pressing member 5 can be any one of a circle, a square, a rectangle, an octagon, an ellipse, and a gear.
[0024]
[Example 1]
FIG. 2 is a circuit block for explaining the first embodiment of the position detection apparatus according to the present invention, in which reference numeral 11 denotes a detection unit, 12 (12x, 12y) are differential amplifiers, and 13 is an A / D converter. , 14 is a detection control unit, 15 is a coordinate conversion unit, 16 is a coordinate switching unit, 17 is an output method storage unit, 18 is an output control unit, 21 (21a, 21b, 21c, 21d) is a Hall element, and 51 is a distance calculation. , 52 is an angle calculation unit, and 53 is a distance output limiting unit.
[0025]
The detection unit 11 includes four magnetic sensors (for example, a Hall element, a semiconductor magnetoresistive element, a magnetosensitive magnetoresistive element, and a GMR element) 21, and the Hall element 21 is 2 along the X axis and the Y axis. They are arranged symmetrically one by one. Magnets are arranged in the vicinity of the center of the four Hall elements 21a, 21b, 21c, and 21d arranged symmetrically on the X axis and the Y axis. The output voltage of the Hall element 21 changes due to the change of the magnetic field due to the movement of the magnet. The differential amplifier 12 differentially amplifies the output signals of the Hall elements 21 in the X-axis direction and the Y-axis direction. When the magnetic field in the Z-axis direction is symmetric with respect to the origin O, that is, when the magnetization direction of the magnet is in the vertical direction, the output signal is set to 0, and when the magnet moves, the differential amplifier 12x, Output signals Xo and Yo are generated at 12y, respectively.
[0026]
Here, the signal from the Hall element 21a arranged in the X-axis direction of the detection unit 11 is X1, the signal from the Hall element 21b is X2, and the Hall element arranged in the Y-axis direction of the detection unit 11 If the signal from 21c is Y1, the signal from the Hall element 21d is Y2, the output of the differential amplifier 12x is Xo, and the output of the differential amplifier 12y is Yo,
Xo = (X1-X2) / (X1 + X2)
Yo = (Y1-Y2) / (Y1 + Y2)
Produces output such that
[0027]
That is, a signal (Xo = (X1−X2) /) obtained by dividing the difference signal (X1−X2) between the Hall elements 21a and 21b arranged in the X axis direction by the sum signal (X1 + X2) of the Hall elements 21a and 21b. (X1 + X2)) and a signal (Yo) obtained by dividing the difference signal (Y1-Y2) of the Hall elements 21c and 21d arranged in the Y-axis direction by the sum signal (Y1 + Y2) of the Hall elements 21c and 21d = (Y1-Y2) / (Y1 + Y2)).
[0028]
Conventionally, the output Xo of the differential amplifier 12x is X1-X2, and the output Yo of the differential amplifier 12y is Y1-Y2. Output signals when the moving distance of the magnet is increased are shown in FIGS. FIG. 5 is a diagram showing the relationship between the output difference between two conventional magnetic sensors and the moving distance of the magnet, and FIG. 6 is a diagram showing the relationship between the output difference / output sum and the moving distance of the magnet. Here, the size of the magnet is 3 mm × 3 mm × 0.8 mm (length × width × height), and the pitch of the two sensors on the axis is 3.25 mm. Gap shown in the figure indicates the distance in the Z-axis direction from the magnet surface to the sensor surface.
[0029]
Conventionally, as shown in FIG. 5, the distance is gradually reduced from 2 mm, but in the present invention, as shown in FIG. 6 (three curves shown on the lower right side in the figure), the difference is within a range of 2 mm or more. It can be seen that the output voltage has increased.
[0030]
The A / D converter 13 converts the output signal (analog value) of the differential amplifier 12 into a digital value. The detection control unit 14 converts the output signal (voltage) from the A / D converter 13 into an X coordinate value and a Y coordinate value. The coordinate conversion unit 15 converts the XY coordinate values (X, Y) output from the detection control unit 14 into polar coordinate values (R, θ).
[0031]
The coordinate switching unit 16 receives both the polar coordinate value output from the coordinate conversion unit 15 and the XY coordinate value output from the detection control unit 14, and either of them is in accordance with an instruction from the output method storage unit 17. One of them is output to the output control unit 18. The output method storage unit 17 stores an output method (XY coordinates / polar coordinates) designated from the outside, and instructs the coordinate switching unit 16 of this. The output control unit 18 controls coordinate value output to the outside.
[0032]
The coordinate conversion unit 15 includes a distance calculation unit 51, an angle calculation unit 52, and a distance output restriction unit 53. The distance calculation unit 51 sets the distance R in the form of R = √ (X ² + Y ² ), for example. The angle calculation unit 52 calculates the angle in the form of θ = tan ⁻¹ (Y / X), for example. The distance output restriction unit 53 compares R calculated by the distance calculation unit 51 with a predetermined limit value Rmax. When R> Rmax, R is converted into Rmax and output. This will be described with reference to FIG.
[0033]
FIG. 3 is an explanatory diagram of the output restriction function. That is, when R in the input coordinate value (R, θ) is larger than Rmax, the output coordinate value is always (Rmax, θ).
[0034]
The function for limiting R is to prevent the display from being disabled in the case of an application that displays in a circular area. However, R does not exceed Rmax mechanically. In the case where this function is not required, for example, the distance output restriction unit 53 may not be provided.
[0035]
FIG. 4 is a circuit block for explaining another embodiment of the position detecting apparatus according to the present invention. Components having the same functions as those in FIG. 2 are denoted by the same reference numerals. In this embodiment, the detection control unit 14, the coordinate conversion unit 15, and the output control unit 18 are connected in series, and there is no coordinate switching unit 16 and output method storage unit 17 in FIG. It is configured to output only.
[0036]
[Example 2]
Next, a second embodiment of the position detection apparatus according to the present invention will be described. The circuit block of the second embodiment is the same as that of the first embodiment described above. The difference from the first embodiment is that the calculation method of the output Xo of the differential amplifier 12x and the output Yo of the differential amplifier 12y is different.
[0037]
The signal from the Hall element 21a arranged in the X-axis direction of the detection unit 11 is X1, the signal from the Hall element 21b is X2, and the signal from the Hall element 21c arranged in the Y-axis direction of the detection unit 11 is If the signal is Y1, the signal from the Hall element 21d is Y2, the output of the differential amplifier 12x is Xo, and the output of the differential amplifier 12y is Yo,
Xo = (X1-X2) / (X1 + X2 + Y1 + Y2)
Yo = (Y1-Y2) / (X1 + X2 + Y1 + Y2)
Produces output such that
[0038]
That is, a signal (Xo = (X1−X2) /) obtained by dividing the difference signal (X1−X2) between the Hall elements 21a and 21b arranged in the X-axis direction by the sum signal (X1 + X2 + Y1 + Y2) of the Hall elements 21a to 21d. (X1 + X2 + Y1 + Y2)) and a signal (Yo) obtained by dividing the difference signal (Y1-Y2) of the Hall elements 21c and 21d arranged in the Y-axis direction by the sum signal (X1 + X2 + Y1 + Y2) of the Hall elements 21a to 21d = (Y1-Y2) / (X1 + X2 + Y1 + Y2)). According to the second embodiment, as shown in FIG. 6 (three curves shown on the upper right side in the figure), it can be seen that the monotonically increasing range is wider than that of the first embodiment.
[0039]
[Example 3]
FIG. 7 is a diagram for explaining still another embodiment of the position detection apparatus according to the present invention. In the figure, reference numeral 22 denotes a detected object to be detected for position, amount of movement, and inclination, and 23 denotes a magnet. Show. A magnet 23 is fixed to the object 22 to be detected, and the position, amount of movement, and degree of inclination of the object 22 to be detected are detected by moving or tilting the magnet 23 on the magnetic sensor 1 shown in FIG. It is configured to be able to. The circuit block is the same as in the first and second embodiments.
[0040]
In the third embodiment, such a configuration makes it possible to detect the amount of movement of the detected object 22 at the 0.1 mm level even when there is a temperature change or magnet variation.
[0041]
【The invention's effect】
As described above, according to the present invention, four magnetic sensors arranged two by two along the X-axis and the Y-axis, and movable or tilted are arranged near the centers of the four magnetic sensors. that a magnet, a position detecting device range of monotonous increase was larger in the output signal with respect to the moving amount of the magnet, the difference signal the X of the two magnetic sensors on the X axis the output value divided by the sum signal of the two magnetic sensors on the axis, the Y-axis on the two output values divided by the sum signal of the two magnetic sensors on the Y-axis the difference signal of the magnetic sensor Are output as position signals, and the output value increases beyond a predetermined range with respect to the moving distance of the magnet. You can get output that doesn't receive In addition, the influence of the distance between the magnet and the magnetic sensor is reduced, and the range of the monotonous increase of the signal with respect to the amount of movement of the magnet is increased, so that the design, adjustment, and assembly are facilitated.
[Brief description of the drawings]
FIG. 1 is a configuration diagram for explaining an embodiment of a pointing device according to the present invention.
FIG. 2 is a circuit block for explaining Example 1 of the position detecting apparatus according to the present invention.
FIG. 3 is an explanatory diagram of an output restriction function.
FIG. 4 is a circuit block for explaining another embodiment of the position detecting apparatus according to the present invention.
FIG. 5 is a diagram showing a relationship between an output difference between two conventional magnetic sensors and a moving distance of a magnet.
FIG. 6 is a diagram showing a case of dividing by two sums and four sums in relation to an output difference / output sum and a moving distance of a magnet.
FIG. 7 is a diagram for explaining still another embodiment of the position detection apparatus according to the present invention.
FIG. 8 is a block diagram showing a magnetic detection circuit of a conventional magnetic detection type pointing device.
FIG. 9 is a diagram illustrating an example of a magnet support mechanism used in a conventional pointing device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Magnetic sensor 2 Magnet 3 Silicone resin 4 as an elastic member 4 Mounting board 5 Pressing member 6 Switch 7 Space part 7a Notch part 11 Detection part 12 (12x, 12y) Differential amplifier 13 A / D converter 14 Detection control part 15 Coordinate conversion unit 16 Coordinate switching unit 17 Output method storage unit 18 Output control unit 21 (21a, 21b, 21c, 21d) Hall element 22 Object to be detected 23 Magnet 31 Detection unit 32 Differential amplifier 33 A / D converter 34 Detection control Unit 35 Output Control Unit 41 Hall Element 51 Distance Calculation Unit 52 Angle Calculation Unit 53 Distance Output Limiting Unit

Claims (2)

Four magnetic sensors arranged two each along the X-axis and the Y-axis, and a magnet arranged so as to be movable or tiltable near the center of the four magnetic sensors, and the amount of movement of the magnets A position detection device in which the range of the monotonic increase of the output signal is increased,
The output value divided by the sum signal of the two magnetic sensors on the X-axis the difference signal of the two magnetic sensors on the X axis, a difference signal of the two magnetic sensors on the Y axis the Y wherein on the shaft two the output value divided by the sum signal of the magnetic sensor output as each position signal, the position detection in which the output value to the movement distance of the magnet is characterized in that to increase above the predetermined range apparatus.   Two magnetic sensors arranged along the X-axis and the Y-axis, each including two magnetic sensors, and magnets arranged so as to be movable or tiltable near the centers of the four magnetic sensors. The position signal is obtained by dividing the difference signal of the two magnetic sensors by the sum signal of the four magnetic sensors and the value obtained by dividing the difference signal of the two magnetic sensors on the Y axis by the sum signal of the four magnetic sensors. A position detection device that outputs as

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