JP2009021117A - Omnidirectional operation switch device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an omnidirectional operation switch device in which the tilting direction of an operation member can be detected with high precision, and which is inexpensive. <P>SOLUTION: The omnidirectional operation switch has a radial pattern 2 having division electrodes 21a to h of which the whole circumference is uniformly split in eight, a conical electrode 3 opposed to the radial pattern, the operation member 4 to tilt a conical electrode, a changeover means 6 to sequentially select the respective division electrodes at a fixed circulation cycle, a capacitance-voltage conversion means 7 in which the capacitance of a capacitor constituted of the conical electrode and the division electrodes is converted to a voltage signal by applying a high frequency signal of 500 kHz, a bandpass filter 8 in which, from a series of voltage signals sequentially converted in each division electrode, a specific frequency component of the circulation cycle is extracted, and a microcomputer 9 to detect a direction corresponding to a phase in which a signal waveform of the specific frequency component becomes maximum or minimum as the tilting operation direction of the operation member 4. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an omnidirectional operation switch device, and more particularly to an omnidirectional operation switch device that detects a tilt direction of an operation member that is tilted in an arbitrary direction around the entire circumference.

  Conventional examples of this type of omnidirectional operation switch device are disclosed in Patent Documents 1 and 2 below. The apparatus disclosed in Patent Document 1 includes a conductive annular portion that tilts in response to a swinging operation of an operation member, and a conductive radial pattern on a printed board that faces the annular portion. Then, the tilting direction of the operation member is detected by detecting the position where the conductive ring portion and the radial pattern are in contact with each other.

  The device disclosed in Patent Document 2 includes a movable electrode that moves in accordance with the swinging operation of the operation member, and a plurality of fixed electrodes that face the movable electrode. Then, the amount of change in capacitance of all the fixed electrodes is calculated from the change in capacitance between the movable electrode and each fixed electrode, and the tilt direction of the operation site is detected.

JP 2003-272486 A JP 2001-325858 A

  However, in the conventional omnidirectional operation switch device of Patent Document 1, the azimuth resolution in the tilt direction of the operation member is limited by the number of radial patterns formed on the printed circuit board.

  Further, Patent Document 2 does not disclose a specific method for obtaining the tilt direction of the operation member from the capacitance value of each fixed electrode. Generally, in the apparatus disclosed in Patent Document 2, the following two methods can be considered as methods for obtaining the tilt direction of the operation member. One is a method of obtaining a tilt direction by performing a vector operation including a known trigonometric function from capacitance values in the X direction and the Y direction on the oscillation detection azimuth plane. The other is a method for obtaining the tilt direction from the capacitance values in the X direction and Y direction on the oscillation detection azimuth plane with reference to a two-dimensional table prepared in advance.

  However, in order to obtain high-precision azimuth resolution by these methods, a large number of arithmetic digits are performed using a high-performance microprocessor, or a huge memory size is used using a large-capacity memory. It is necessary to refer to a two-dimensional table. For this reason, whichever method is adopted leads to an increase in cost.

  Accordingly, an object of the present invention is to provide an inexpensive omnidirectional operation switch device that can detect the tilting direction of an operation member with high accuracy.

  In order to achieve the above object, an omnidirectional operation switch device according to the present invention has a radial pattern having a plurality of divided electrodes obtained by dividing the entire circumference at equal angles, and is opposed to the radial pattern and in any direction of the entire circumference. A conical electrode disposed so as to be tiltable, an operation member for tilting the conical electrode, a switching means for sequentially selecting each of the divided electrodes of the radial pattern at a constant cyclic period, a conical electrode, and the switching means selected The cyclic period is determined from the capacitance-voltage conversion means for converting the capacitance of the capacitor constituted by the divided electrodes to a voltage signal and a series of voltage signals sequentially converted for each divided electrode. The extraction means for extracting a specific frequency component for one cycle is associated with the phase of the signal waveform of the specific frequency component and the direction viewed from the center of the radial pattern, and the signal waveform is maximized or minimized. It is characterized in that it comprises the operation direction detecting means for detecting as the operation direction of the corresponding direction the operating member, to.

  Thus, in the present invention, the tilting direction of the operating member is detected by detecting the phase at which the signal waveform of the specific frequency component corresponding to the cyclic period of the switching means is maximized or minimized. For this reason, the detection accuracy of the tilt direction of the operation member is not limited by the division angle of the radial pattern. Further, the present invention does not require a high-performance microprocessor or a large-capacity memory that causes an increase in cost in order to improve the detection accuracy of the tilt direction. Therefore, according to the omnidirectional operation switch device of the present invention, the tilt direction of the operation member can be detected with high accuracy, and an inexpensive omnidirectional operation switch device can be provided.

Preferably, in the present invention, the capacitance-voltage conversion means includes a high-frequency signal source and a load resistor provided between the capacitance and the high-frequency signal source or between the capacitor and the ground potential. The extraction means is connected between the capacitor and the load resistor.
As a result, the capacitance of the capacitor is converted into a voltage at a node between the capacitor and the load resistor.

In the present invention, it is preferable that the extraction unit includes a filter that allows a frequency component including a frequency corresponding to the cyclic period to pass therethrough and blocks a frequency component of the high-frequency signal.
The filter removes the frequency component of the high-frequency signal from the series of voltage signals and selectively extracts a continuous signal waveform having a specific frequency.

In the present invention, it is preferable to further include an operation amount detection means for detecting a tilt operation amount of the operation member based on the maximum amplitude of the signal waveform of the specific frequency component.
Thereby, the operation amount is also detected together with the direction of the tilting operation of the operation member.

  According to the present invention, it is possible to provide an inexpensive omnidirectional operation switch device that can detect the tilting direction of the operation member with high accuracy.

Embodiments of an omnidirectional operation switch device of the present invention will be described below with reference to the accompanying drawings.
First, the configuration of the electrodes of the omnidirectional operation switch device will be described with reference to FIG. FIG. 1 is a perspective view schematically showing a device electrode portion of the omnidirectional operation switch of the embodiment.

  As shown in FIG. 1, the electrodes of the omnidirectional operation switch device are formed on the printed circuit board 1 and have a radial pattern 2 having a plurality of divided electrodes 21 whose entire circumference is divided at equal angles, and are opposed to the radial pattern 2. And a conical electrode 3 disposed so as to be tiltable in an arbitrary direction along the entire circumference. Each divided electrode 21 and the conical electrode 3 constitute a capacitor C.

  In the present embodiment, the radial pattern 2 is formed on the printed board, but the configuration of the radial pattern is not limited to this, and for example, a conductive material such as a metal plate is used without using the printed board. You can make it. In the present embodiment, the conical electrode 3 is made of a conductive resin. However, the material of the conical electrode 3 is not limited to this, and may be made of any conductive material such as a metal material. The operation member 4 is made of an insulating molding resin such as ABS resin (acrylonitrile-butadiene-styrene resin).

  Further, an operation member 4 for tilting the conical electrode 3 is attached to the conical electrode 3. The operation member 4 extends in a rod shape on the conical center axis of the conical electrode 3. In the present embodiment, the tilt direction and tilt angle of the operation member 4 are the same as the tilt direction and tilt angle of the conical electrode 3.

  In addition, the shape of the operation member 4 is not limited to a rod shape, and can be any suitable shape. Further, the tilting direction of the operation member 4 and the tilting direction of the conical electrode 3 do not necessarily coincide with each other. For example, the operating member 4 and the conical electrode 3 are connected via a hinge, and the hinge is tilted about the fulcrum so that the tilting direction of the operating member and the tilting direction of the conical shape are opposite to each other. Good.

As shown in FIG. 2A, the radial pattern 2 of the present embodiment is formed of divided electrodes 21a to 21h that are divided into eight equal parts every 45 °. Accordingly, the divided electrodes 21a to 21h are fan-shaped electrodes having the same shape and have the same area.
Note that the number of divisions of the radial pattern 2 is not limited to eight equal divisions. Preferably, it is divided into three or more equal divisions.

  2B, when the central axis of the conical electrode 3 is perpendicular to the plane of the radial pattern 2, the distance between the conical electrode 3 and each of the divided electrodes 21a to 21h is equal to each other. The capacities Ca to Ch of the capacitors respectively constituted by the conical electrode 3 and the divided electrodes 21a to 21h are equal to each other.

  On the other hand, as shown by the broken line in FIG. 2b, when the cone electrode 3 tilts in the direction indicated by the arrow X in FIG. 2A, the distance between the cone electrode 3 and the divided electrodes 21c and 21d decreases. As a result, the capacitances Cc and Cd of these capacitors are increased. On the other hand, in this case, the interval between the conical electrode 3 and the divided electrodes 21g and 21h is increased. As a result, the capacitances Cg and Ch of these capacitors are reduced.

  As a result, the distribution of the capacitances Ca to Ch of the capacitors formed by the conical electrode 3 and each of the divided electrodes 21a to 21h has the maximum capacitance value in the X direction and the minimum in the direction opposite to the X direction. . That is, the magnitude relationship of each capacitance is Cc, Cd> Cb, Ce> Ca, Cf> Cg, Ch.

Further, a conductive circular pattern 22 arranged concentrically with the radial pattern is formed near the center of the radial pattern 2. The circular pattern 22 is grounded. The divided electrodes 21a to 21h and the circular pattern 22 and the divided electrodes 21a to 21h are insulated from each other. The capacitance between the circular pattern 22 and the cone electrode 3 is constant regardless of the tilt of the cone electrode 3.
The circular pattern 22 may be omitted. In that case, the conical electrode 3 may be connected to the ground potential.

  Further, as shown in FIG. 2B, the conical electrode 3 is arranged so that the apex of the conical shape faces downward and the apex is positioned at the center of the radial pattern 2 of the printed circuit board 1. A mounting hole 11 is opened at the center of the radial pattern 2 of the printed circuit board 1. A screw rod 4 a extending from the apex of the conical electrode 3 passes through the attachment hole 11. The screw rod 4a is attached to the printed circuit board 1 by a spring 5a and a nut 5b. Thereby, the conical electrode 3 can be tilted in any direction of the entire circumference. That is, the conical electrode 3 can move so that the conical axis is inclined with respect to the normal of the plane of the radial pattern 2 with the vicinity of the apex of the conical shape as a fulcrum.

As shown in FIGS. 1 and 2B, the operation member 4 stands upright perpendicular to the plane of the printed circuit board 1 in a state where no force is applied. The operation member 4 can be tilted until the conical bus of the conical electrode 3 is parallel to the plane of the radial pattern 2.
In the present embodiment, as shown by a broken line in FIG. 2B, the operation member 4 is fixed to the conical electrode 3, so that the tilt direction and tilt angle of the operation member 4 and the tilt direction of the conical electrode 3 are fixed. And the tilt angle coincide with each other.

  Next, with reference to FIG. 3, the structure of parts other than the electrode etc. of the omnidirectional operation switch apparatus of embodiment of this invention is demonstrated. FIG. 3 is a schematic diagram of the overall configuration of the omnidirectional operation switch device of the present embodiment. In FIG. 3, illustration of the conical electrode 3 and the operation member 4 is omitted.

  As shown in FIG. 3, the omnidirectional operation switch device of the present embodiment has the divided electrodes 21 a to 21 h of the radial pattern 2 in the clockwise direction in FIG. 2A in addition to the electrodes shown in FIG. Capacitance for converting a capacitance of a capacitor formed by the switching means 6 that sequentially selects at a constant cyclic cycle, the conical electrode 3, and the divided electrode 21 selected by the switching means 6 into a voltage signal− The voltage converting means 7, the extracting means 8 for extracting a specific frequency component having a cyclic period as one cycle from a series of voltage signals sequentially converted for each of the divided electrodes 21a to 21h, and the phase of the signal waveform of the specific frequency component And an operation direction detecting means 9 for detecting the direction corresponding to the phase where the signal waveform is maximized or minimized as the operation direction of the operation member 4.

  Furthermore, the omnidirectional operation switch device of the present embodiment further includes an operation amount detection means for detecting the tilt operation amount of the operation member 4 based on the maximum amplitude of the signal waveform of the specific frequency component. In the present embodiment, the operation direction detection means 9 and the operation amount detection means are constituted by the microprocessor 9.

The switching means 6 of the present embodiment has eight input ends 61a to 61h connected to the respective divided electrodes 21a to 21h, and one output end 62. Then, the switching unit 6 sequentially switches the connection between the input terminals 61a to 61h and the output terminal 62 so as to circulate at a constant cycle of 10 milliseconds (100 Hz). Thereby, each divided electrode 21a-21h is selected every 10 milliseconds.
Note that the cyclic period of the switching unit 6 is not limited to 10 milliseconds, and the connection can be switched at an arbitrary fixed period.

  In the present embodiment, the capacitance-voltage conversion unit 7 and the extraction unit 8 are connected to the output terminal of the switching unit 6.

The capacitance-voltage conversion means 7 of this embodiment is composed of a high frequency signal source 71 and a load resistor 72. The load resistor 72 is provided between the capacitor and the high frequency signal source 71, that is, between the output terminal 62 of the switching unit 6 and the high frequency signal source 71. The high frequency signal source 71 generates a high frequency signal composed of a sine wave having a frequency of 500 Hz and a peak-to-peak voltage of 5 Vpp.
Note that the frequency of the high-frequency signal to be applied is not limited to 500 kHz, and any suitable frequency can be selected.

  The extraction unit 8 is connected between the capacitor and the load resistor 72, specifically, between the output terminal 62 of the switching unit 6 connected to the capacitor and the load resistor 72. As a result, the voltage signal at the node between the output terminal 62 and the load resistor 72 is input to the extraction unit 8.

  The extraction means 8 is composed of a bandpass filter 8. The band-pass filter 8 allows a frequency component including a frequency of 100 Hz corresponding to a cyclic period of 10 milliseconds of the switching unit 6 to pass, and blocks a frequency component of a high-frequency signal having a frequency of 500 kHz. The specific frequency component reflects a change in the capacitance of the capacitor corresponding to each of the divided electrodes 21 a to 21 h due to the tilt of the operation member 4.

  A half-wave rectifier circuit that allows only the positive voltage of the input signal to pass may be provided on the input side of the bandpass filter 8. Further, the extraction means 8 may be constituted by a low pass filter.

  The signal of the specific frequency component output from the band pass filter 8 is input to the T1 terminal and T2 terminal of the microcomputer 9, respectively. A switching signal is input from the terminal T3 of the microcomputer 9 to the control terminal C of the switching means 6. In response to the switching signal, the switching unit 6 sequentially switches the connection.

  The signal input to the T1 terminal of the microcomputer 9 is subjected to analog / digital conversion. The microcomputer 9 functions as an operation amount detection unit, and detects the tilt operation amount of the operation member 4 based on the maximum amplitude of the converted signal waveform of the specific frequency component.

  Further, the microcomputer 9 functions as the operation direction detecting means 9, and the signal input to the T2 terminal detects the phase at which the signal waveform is maximized or minimized by a known timer interruption. The detected phase corresponds to the tilting operation direction of the operation member 4. The detected tilt operation amount and tilt operation direction are output as operation signals from the output terminal TO to an external device (not shown).

Next, the operation of the omnidirectional operation switch device of this embodiment will be described with reference to the timing chart of FIG.
The first stage timing chart of FIG. 4 represents capacitors Ca to Ch corresponding to the divided electrodes 21a to 21h. The switching unit 6 selects the divided electrodes 21a to 21h in a cyclic cycle in the order shown in FIG.

  The timing charts of the second and third stages in FIG. 4 show signal waveforms I and II output from the output terminal 62 of the switching unit 6, respectively. These signal waveforms I and II represent a series of voltage signal waveforms that are sequentially subjected to capacitance-voltage conversion for each divided electrode. However, the signal waveform I in the second stage shows a case where the operation member 4 is neutral, that is, a case where the operation member 4 stands perpendicular to the plane of the radiation pattern 2. Further, the signal waveform II in the third stage shows the case where the operation member 4 is tilted in the direction indicated by the arrow X in FIG.

  The timing chart at the fourth stage in FIG. 4 shows the signal waveform III of the specific frequency component output from the band pass filter 8. The period of the signal waveform III of the specific frequency component coincides with a period of 10 milliseconds (100 Hz) in which the switching unit 6 makes a round of selection of each of the divided electrodes 21a to 21h. The phase of the signal waveform III of the specific frequency component is associated with the direction viewed from the center of the radial pattern 2 with the direction of the boundary between the divided electrode 21a and the divided electrode 21h being 0 °.

  First, when the operation member 4 is neutral, the capacitances Ca to Ch of the capacitors are substantially equal to each other. For this reason, when each capacitor is viewed as an impedance, the voltage drops are almost equal to each other. As a result, the signal level (amplitude) of the second-stage signal waveform I in FIG. 4 is constant regardless of the selected divided electrode.

  The component of the signal waveform I substantially includes only a high frequency component of 500 kHz and does not include a specific frequency component of 100 Hz. As a result, the signal level of the voltage signal of the specific frequency component output from the band pass filter 8 to which the signal waveform II is input is substantially 0V. Thereby, it is detected that the operation member 4 is neutral.

  On the other hand, when the operation member 4 is tilted, the capacitances Ca to Ch of the capacitors have different values. For example, when the operation member 4 is tilted in the direction indicated by the arrow X in FIG. 2A, the capacitances Ca to Ch of the capacitors respectively formed by the conical electrode 3 and the divided electrodes 21a to 21h are in the X direction. At the maximum capacitance value and the minimum in the direction opposite to the X direction. That is, the magnitude relationship of each capacitance is Cc, Cd> Cb, Ce> Ca, Cf> Cg, Ch.

  For this reason, the amplitude of the signal waveform II also changes corresponding to the capacitance of the capacitor selected by the switching means 6, as shown in FIG. As a result, the signal waveform II includes a specific frequency component that changes at 100 Hz corresponding to a cycle in which the selection of the switching means 6 is completed in addition to the high-frequency component of 500 kHz.

  By passing the voltage signal of the signal waveform II through the bandpass filter 8, a specific frequency component of the signal waveform III is extracted. As shown in FIG. 4, the extracted signal waveform III is a sine wave having an amplitude Vs that is minimum at the phase tX.

  The signal waveform III input to the terminal T1 of the microprocessor 9 is analog / digital (A / D) converted. The angle of the tilting operation of the operation member 4, that is, the tilting operation amount is detected from the amplitude Vs of the converted signal. The tilting operation amount of the operation member 4 is substantially proportional to the amplitude of the signal waveform III.

  Further, the tilt direction X of the operation member 4 is detected from the timing of the phase tX of the signal waveform III input to the terminal T2 of the microprocessor 9. In FIG. 4, the phase of the signal waveform III is associated with the same clockwise angle as the cyclic direction of the switching means 6 starting from the boundary between the divided electrode 21a and the divided electrode 21h around the entire circumference of the radial pattern 2. . The phase tX corresponds to X ° that is the tilting direction X of the operation member 4.

  Specifically, this phase tX is detected by a timer interrupt. The timer interrupt is generated at a timing when the signal level of the signal waveform III input to the terminal T2 of the microprocessor 9 becomes the center voltage indicated by the alternate long and short dash line IV in FIG. A predetermined timer value at timing t0 and timing t1 at which the signal waveform III crosses the alternate long and short dash line IV is sampled. Then, from the timing t1 and the timing t0, the median value tX of these timings is calculated, and the tilt direction of the operation member 4 corresponding to the median value is detected.

  The detection accuracy of the tilt direction depends on the detection accuracy of the phase such as the minimum value of the signal waveform of the specific frequency component. In this embodiment, the phase detection accuracy depends on the sampling accuracy at the time of timer interruption, but is not limited by the number of divisions of the radial pattern 2 by the division electrodes. For this reason, high azimuth | direction resolution is implement | achieved in the detection of a tilt direction irrespective of the division | segmentation number of a radial pattern.

In the above-mentioned embodiment, although the example which comprised this invention on the specific conditions was demonstrated, this invention can perform a various change and combination, and is not limited to this. For example, the capacitance-voltage conversion means is not limited to that shown in the embodiment.
As a modification of the capacitance-voltage conversion means, a high-frequency signal may be applied to the conical electrode side via a circular pattern, and the output end of the switching means may be grounded via a load resistor. In that case, the signal waveform of the specific frequency component becomes maximum at a phase corresponding to the tilting direction of the conical electrode.

  As another modification of the capacitance-voltage conversion means, a high frequency signal is applied to the conical electrode side via a circular pattern via a load resistor, and a microcomputer is provided via an extraction means such as a bandpass filter. On the other hand, the output end of the switching means may be grounded. In that case, the signal waveform of the specific frequency component is minimized at a phase corresponding to the tilt direction of the conical electrode.

  As another modification of the capacitance-voltage conversion means, the conical electrode side is grounded via a load resistor via a circular pattern, and connected to a microcomputer via an extraction means such as a bandpass filter, On the other hand, you may comprise so that a high frequency signal may be applied to the output terminal of a switching means. In that case, the signal waveform of the specific frequency component becomes maximum at a phase corresponding to the tilting direction of the conical electrode.

  In the above-described embodiment, the conical electrode and the radial pattern are provided on the same surface side of the printed board, but the arrangement of the conical electrode and the radial pattern is not limited to this. For example, the conical electrode may be disposed on the upper surface of the printed circuit board, and the radial pattern may be formed on the lower surface of the printed circuit board.

  In the above-described embodiment, the conical electrode and the operation member are provided on the same surface side of the printed board, but the arrangement of the conical electrode and the operation member is not limited to this. For example, the conical electrode may be provided on the lower surface side of the printed circuit board with the apex of the cone facing the printed circuit board side, and the operation member may be connected to the conical electrode through the printed circuit board from the upper surface side of the printed circuit board.

  Furthermore, the operating member can be combined with various functions as well as tilting. For example, the operation member is added with one or both of a function of a known push switch that operates by pressing from the vertical direction with respect to the printed board and a function of a rotary dial that functions by rotating around the operation member. May be.

  As described above, the omnidirectional operation switch device of the present invention can accurately detect the rotational position of the dial in a non-contact manner and can provide a highly reliable dial structure against external noise, condensation, and the like. In addition to being suitable for use as a dial for an air conditioning control device for automobiles, it can also be used as an omnidirectional operation switch device for other general electric products.

It is the perspective view which showed typically the electrode etc. of the omnidirectional operation switch apparatus of embodiment of this invention. (A) is a top view of the radial pattern of embodiment, (b) is a longitudinal cross-sectional view of the electrode of embodiment. It is a block diagram of the omnidirectional operation switch apparatus of embodiment. It is a timing chart of operation | movement of the omnidirectional operation switch apparatus of embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Printed circuit board 2 Radial pattern 3 Conical electrode 4 Operation member 5a Spring 5b Nut 6 Changeover switch 7 Capacitance-voltage conversion means 8 Extraction means, band pass filter 9 Microcomputer, operation direction detection means 21a-21h Divided electrode 22 Circular pattern 71 High-frequency signal source 72 Load resistance

Claims (4)

A radial pattern having a plurality of divided electrodes with the entire circumference divided at equal angles;
A conical electrode opposed to the radial pattern and arranged so as to be tiltable in any direction along the entire circumference;
An operation member for tilting the conical electrode;
Switching means for sequentially selecting each of the divided electrodes of the radial pattern at a constant cyclic period;
Capacitance-voltage conversion means for converting a capacitance of a capacitor constituted by the conical electrode and the divided electrode selected by the switching means into a voltage signal;
Extraction means for extracting a specific frequency component having the cyclic period as one period from a series of voltage signals sequentially converted for each of the divided electrodes;
An operation direction that correlates the phase of the signal waveform of the specific frequency component with the direction viewed from the center of the radial pattern, and detects the direction corresponding to the phase at which the signal waveform is maximized or minimized as the operation direction of the operation member. Detection means;
An omnidirectional operation switch device comprising: The capacitance-voltage conversion means includes a high-frequency signal source,
A load resistor provided between the capacitor and the high-frequency signal source or between the capacitor and a ground potential;
Have
2. The omnidirectional operation switch device according to claim 1, wherein the extraction means is connected between the capacitor and the load resistor. The extraction means includes a filter that allows a frequency component including a frequency corresponding to the cyclic period to pass therethrough and blocks the frequency component of the high-frequency signal.
The omnidirectional operation switch device according to claim 2. The operation amount detecting means for detecting a tilt operation amount of the operation member based on the maximum amplitude of the signal waveform of the specific frequency component is further provided. Directional operation switch device.

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