JP2011232038A - Capacitance type proximity sensor apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitance type proximity sensor apparatus capable of detecting an operation of a detected object as a natural movement.SOLUTION: The capacitance type proximity sensor apparatus includes: four electrodes 13a to 13d having substantially L-shaped parts which are arranged in respective corners of a rectangular reference surface having four sides and four corners along two adjacent sides, in the reference surface; a drive circuit 16 for applying a drive voltage to a pair of the electrodes confronting each other in a diagonal direction of the reference surface as a drive electrode, out of the four electrodes 13a to 13d; and a detection circuit 17 for detecting a signal output from the pair of the detection electrodes confronting each other in the diagonal direction of the reference surface, out of the four electrodes 13a to 13d.

Description

  The present invention relates to a capacitive proximity sensor device that detects the proximity of an object to be detected.

  Conventionally, as a device for detecting a detection target such as a human body, a capacitance type detection device that detects the approach of the detection target in a planar direction has been proposed. In such a capacitance type detection device, four electrodes are arranged on the sensor surface so as to form a capacitance between the electrodes (for example, see Patent Document 1). The four electrodes are arranged along four sides of a rectangular sensor surface having four sides and four corners.

International Publication No. 2008/093682

  In recent years, the aspect ratio of a display of an electronic device is shifting from 4: 3 to 16: 9, and the aspect ratio is increasing. When detecting the approach of a human hand using the electrode arrangement disclosed in Patent Document 1 around such a horizontally long display or around a horizontally long keyboard, the human palm is long in the vertical direction. Therefore, as shown in FIG. 6A, when the X direction is detected by a pair of opposing electrodes 101b (X1) and 101d (X2) extending in the vertical direction, the palm 31 and the electrodes 101b and 101d are As shown in FIG. 6B, sensitivity can be obtained because of stronger coupling, but when detecting the Y direction with a pair of opposing electrodes 101a (Y1) and 101c (Y2) extending in the lateral direction, the palm 31 is used. And the electrodes 101a and 101c have a narrow proximity area, and the ratio of the portion that does not couple with the palm 31 between the electrodes 101a and 101c increases, resulting in a decrease in sensitivity. That. For this reason, especially when applied to a long and large screen in which the electrodes 101a and 101c are long, the operation conscious of the user does not match the output of the sensor. It has been found that there are cases where it is not possible to detect a natural movement.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a capacitive proximity sensor device capable of performing detection that makes a natural movement with respect to the operation of the detection target.

  The electrostatic capacity type proximity sensor device of the present invention is substantially L arranged at each corner of the reference surface so as to be along two adjacent sides in a rectangular reference surface having four sides and four corners. Four electrodes having a letter-shaped portion, a drive circuit that applies a drive voltage using a pair of electrodes opposed to each other in the diagonal direction of the reference plane as a drive electrode, and the reference plane of the four electrodes And a detection circuit for detecting signals output from a pair of detection electrodes opposed in the diagonal direction.

  According to this configuration, since there are four electrodes having substantially L-shaped portions at each corner of a rectangular reference surface (sensor surface) along two adjacent sides, the center positions of the sensor surface in the vertical and horizontal directions Thus, the output can be increased, and the detection can be performed with natural movement with respect to the operation of the detected object.

  The capacitance type motion detection device of the present invention processes the position information of the detected object calculated by the capacitance type proximity sensor device and the calculation circuit with a predetermined time constant, and the motion of the detected object is detected. Motion detection means for performing detection.

  Since the capacitive proximity sensor device of the present invention has four electrodes having substantially L-shaped portions at each corner of a rectangular reference surface (sensor surface) along two adjacent sides, the sensor surface The output can be increased at the center position of the top, bottom, left, and right, and detection that makes a natural movement with respect to the operation of the detected object can be performed.

1 is a configuration diagram of a capacitive proximity sensor device according to an embodiment of the present invention. FIG. It is a figure which shows an example of electrode arrangement | positioning of the sensor part of the electrostatic capacitance type proximity sensor apparatus which concerns on embodiment of this invention. (A), (b) is a figure which shows the detection principle of the to-be-detected body of the X-axis direction of the electrostatic capacitance type proximity sensor apparatus which concerns on embodiment of this invention, and a Y-axis direction. It is a figure which shows the motion of the to-be-detected body of the electrostatic capacitance type proximity sensor apparatus which concerns on embodiment of this invention, and the change of an electrostatic capacitance. (A), (b) is a figure for demonstrating the detection state of the electrostatic capacitance type proximity sensor apparatus which concerns on embodiment of this invention, (c), (d) is embodiment of this invention. It is a figure which shows the output of the electrostatic capacitance type proximity sensor apparatus which concerns on a form. (A), (b) is a figure for demonstrating the detection state of the conventional capacitive proximity sensor apparatus, (c) is a figure which shows the output of the conventional capacitive proximity sensor apparatus. is there. It is a figure which shows the output of the capacitive proximity sensor apparatus which concerns on embodiment of this invention, and the conventional capacitive proximity sensor apparatus. It is a figure which shows the difference of the output range between the capacitive proximity sensor apparatus which concerns on embodiment of this invention, and the conventional capacitive proximity sensor apparatus.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a configuration diagram of a capacitive proximity sensor device according to the present embodiment. As shown in the figure, the proximity sensor device according to this embodiment includes a sensor unit 11 that detects the proximity of the detected object, and the position of the detected object based on the output signal detected by the sensor unit 11. And a control circuit unit 12 for calculation.

  The sensor unit 11 includes four electrodes 13a to 13d arranged in the sensor surface 13 as a detection reference surface. Each electrode 13a-13d is arrange | positioned at predetermined intervals so that an electrostatic capacitance may be formed between each adjacent electrode. As shown in FIGS. 1 and 2, the four electrodes 13 a to 13 d are arranged so as to extend along two adjacent sides in a rectangular reference surface (sensor surface) 13 having four sides and four corners. It is arranged at each corner. Each of the four electrodes 13a to 13d has a substantially L-shaped portion in which a small electrode extending in the vertical direction and a small electrode extending in the horizontal direction are combined at each corner. A pair of electrodes facing each other in the diagonal direction of the reference plane among the four electrodes 13a to 13d is a drive electrode or a detection electrode. With such an electrode arrangement, the wiring can be laid out collectively, which facilitates wiring design.

  The control circuit unit 12 includes a multiplexer 14 serving as a switching unit for the electrodes 13a to 13d of the sensor unit 11, and a CPU 15 serving as a calculation unit that calculates the position of the detection target from the signals output from the electrodes 13a to 13d. Prepare. A drive circuit 16 is provided between the CPU 15 and the multiplexer 14 to apply a drive voltage to the electrodes 13a to 13d switched as drive electrodes. A detection circuit 17 is provided between the CPU 15 and the multiplexer 14 to detect output signals from the electrodes 13a to 13d switched as detection electrodes.

  The multiplexer 14 is connected to the electrodes 13 a to 13 d of the sensor unit 11 and is connected to the drive circuit 16 and the detection circuit 17, and switches the connection of the electrodes 13 a to 13 d to the drive circuit 16 and the detection circuit 17. The multiplexer 14 is connected to the CPU 15, and is configured to be able to switch and control connection of the electrodes 13 a to 13 d by a switching signal from the CPU 15. The multiplexer 14 connects electrodes 13a to 13d (hereinafter also simply referred to as drive electrodes) serving as drive electrodes to the drive circuit 16, and electrodes 13a to 13d (hereinafter also simply referred to as detection electrodes) serving as detection electrodes to the detection circuit. 17 is connected.

  The drive circuit 16 includes an oscillation circuit (not shown), and applies a drive voltage to the electrodes 13 a to 13 d serving as drive electrodes by the multiplexer 14. The timing of application of the drive voltage is controlled by the CPU 15.

  The detection circuit 17 is connected to the electrodes 13a to 13d serving as detection electrodes via the multiplexer 14, and is connected to the amplification circuit 18. The amplified output signal is A / D converted and output to the CPU 15. The A / D converter 19 is provided.

  The amplification circuit 18 includes a positive terminal and a negative terminal, amplifies signals output from the electrodes 13 a to 13 d switched as detection electrodes by the multiplexer 14, and outputs the amplified signals to the A / D converter 19.

  In the present embodiment, the multiplexer 14 detects the detected object position in the X-axis direction included in the sensor surface 13 that is the detection reference surface and in the Y-axis direction orthogonal to the X-axis direction in the sensor surface 13. The pair of electrodes 13a to 13d facing each other in the diagonal direction of the detection reference plane are connected to the amplifier circuit 18 as detection electrodes. In this case, one of the detection electrodes 13a to 13d is connected to the positive terminal of the amplifier circuit 18 and an output signal is input, and the other detection electrodes 13a to 13d are connected to the negative terminal and the output signal is input. . In the amplifying circuit 18, the input output signals of the pair of detection electrodes 13a to 13d are differentially amplified, and a difference value between the output signals is detected.

  Thus, in the present embodiment, in one amplifier circuit 18, the output signals from the detection electrodes 13a to 13d are amplified by the difference between the signals output from the pair of detection electrodes 13a to 13d according to the detection direction. Then, amplification according to the difference between the output signals of the detection electrodes 13a to 13d and the output signal of the reference signal is switched in a time division manner for amplification. Thereby, detection in the X-axis direction and the Y-axis direction can be performed without providing the amplifier circuit 18 on each axis.

  The A / D converter 19 performs filtering processing and digital conversion on the output signal amplified by the amplifier circuit 18 and outputs the result to the CPU 15. A difference value or the like is detected from the output signal input to the CPU 15 by the CPU 15 as a detection circuit. The difference value may be detected by the A / D converter 19. In addition, the CPU 15 as the calculation means calculates the position information of the detected object using the detected output signal.

  Next, with reference to FIG. 2, the electrode switching of the sensor unit 11 of the capacitive proximity sensor device according to the present embodiment will be described in detail. In the proximity sensor device according to the present embodiment, the multiplexer 14 switches the connection of the electrodes 13a to 13d arranged in the sensor unit 11 to the drive circuit or the detection circuit according to the detection direction, and switches the drive electrode and the detection electrode. The detected object is detected by. When detecting an object to be detected in the X-axis direction, the electrodes 13a and 13c opposed in one diagonal direction are switched as drive electrodes, and the electrodes 13b and 13d opposed in the other diagonal direction are switched as detection electrodes. The output signals of the detection electrodes 13b and 13d may be calculated as a difference value between the absolute values of the output signals, or may be calculated by inverting the sign of one of the output signals.

  When detecting an object to be detected in the Y-axis direction, the electrodes 13b and 13d opposed in the other diagonal direction are switched as drive electrodes, and the electrodes 13a and 13c opposed in one diagonal direction are switched as detection electrodes. Similar to the detection in the X-axis direction, the difference between the output signals of the detection electrodes 13a and 13c may be calculated by inverting the sign of one of the output signals.

Next, with reference to FIGS. 3A and 3B, the detection principle of the detection target in the X-axis direction and the Y-axis direction in the capacitive proximity sensor device according to the present embodiment will be described. As shown in FIG. 3A, in the detection in the X-axis direction and the Y-axis direction, the pair of electrodes 13a and 13d facing each other as the drive electrodes are switched, and the other pair of electrodes 13b and 13c facing each other are used as the detection electrodes. Switched. In this case, the driving electrodes 13a, electrostatic capacitance _{C x1} between the electrode 13d and the detection electrode 13b is formed, the driving electrodes 13a, electrostatic capacitance _{C x2} is formed between the electrode 13d and the detection electrode 13c. And the position of the hand as the to-be-detected body 31 is detectable by taking the difference of this electrostatic capacitance _Cx1 , _Cx2 . FIG. 3A shows a case where the position of the detection target 31 is detected when the detection target 31 moves in the X-axis direction.

FIG. 3B is a diagram illustrating an example of a detection principle when different electrode arrangements are employed in the capacitive proximity sensor device according to the present embodiment. The example shown in FIG. 3B is an example in which an electrode 13e as a drive electrode is arranged in the center, and electrodes 13f and 13g as detection electrodes are arranged on both sides thereof. In this case, the capacitance _{C 1} is formed between the electrode 13e and the electrode 13f, the electrostatic capacitance _{C 2} is formed between the electrode 13e and the electrode 13 g. The position of the detection target 31 can be detected by taking the difference between the capacitances C ₁ and C ₂ .

Furthermore, with reference to FIG. 3A and FIG. 4, the movement of the detection target 31 and the change in capacitance will be described. In the example shown in FIG. 3A, a capacitance C _x1 is formed between the detection electrode 13b and the drive electrodes 13a and 13d, and a capacitance is formed between the detection electrode 13c and the drive electrodes 13a and 13d. C _x2 is formed. When the detected body 31 moves in any direction of the X-axis direction (left-right direction), electric lines of force (not shown) formed between the electrodes 13a to 13d are absorbed by the detected body 31 and electrostatic capacity is detected. C _x1 and C _x2 change. For example, when the detection target 31 moves to the left side, the capacitance C _x1 increases and the capacitance C _x2 decreases. For this reason, when the detected body 31 moves in the X-axis direction (left-right direction), the difference in capacitance value (C _x2 -C _x1 ) is taken, and the amount of change in capacitance is shown in FIG. Thus, it becomes possible to detect the positional information and movement (motion) of the detected body 31 in the X-axis direction (left-right direction) of the detected body.

  When detecting the detection target in the Y-axis direction, the upper and lower electrodes 13a and 13d of the sensor unit 11 are used as detection electrodes, and the left and right electrodes 13b and 13c are used as drive electrodes. Thus, position information and motion of the detected object are detected. Therefore, in the capacitance type motion detection device including the capacitance type proximity sensor device according to the present invention, the position information of the detected object calculated by the calculation circuit of the capacitance type proximity sensor device is obtained at a predetermined time. The motion of the detected object is detected by processing with constants.

  Next, the operation of the capacitive proximity sensor device according to the present embodiment configured as described above will be described with reference to FIG. 1 again. First, the multiplexer 14 switches arbitrary electrodes 13a to 13d as drive electrodes and detection electrodes according to the detection direction. Next, the drive voltage whose timing is controlled by the CPU 15 is applied from the drive circuit 16 to the drive electrodes. A signal corresponding to the capacitance is output from the detection electrode by the drive voltage applied to the drive electrode.

Specifically, for example, a drive voltage is applied using the electrode 13b (Y1) and the electrode 13d (Y2) as drive electrodes (D +), and from the electrodes 13c (X1) (S +) and the electrodes 13a (X2) (S−). Capacitance value is detected differentially. Further, the drive electrode and the detection electrode are switched, and the drive voltage is applied using the electrode 13c (X1) and the electrode 13a (X2) as the drive electrode (D +), and the electrode 13b (Y1) (S +) and the electrode 13d (Y2) ( The capacitance value is detected differentially from S-). Since the output obtained in this manner is rotated 45 degrees on the XY plot, the output is corrected by adding 45 degrees as in the following equation.
X = Acos (45 deg) + Bsin (45 deg)
Y = −Asin (45 deg) + B cos (45 deg)

  Next, the signal output from the detection electrode is input to the detection circuit 17 and input to the amplification circuit 18 to be amplified. The amplified output signal is filtered and A / D converted by the A / D converter 19 and input to the CPU 15. The CPU 15 detects the position information and operation of the detection target based on the input output signal. As described above, in the proximity sensor device according to the present embodiment, the position information and the operation of the detected object are detected based on the capacitance of the sensor unit 11 generated by the approach of the detected object.

Next, examples performed for clarifying the effects of the present invention will be described.
FIGS. 5A and 5B are diagrams for explaining a detection state of the capacitive proximity sensor device according to the embodiment of the present invention. FIG. 5A shows a state where the hand, which is the detection target, is placed on the right side in the capacitive proximity sensor device having the electrode arrangement shown in FIG. FIG. 5C shows sensor outputs in the X-axis direction and the Y-axis direction at this time. FIG. 5B shows a state where the hand, which is a detection object, is placed in the center in the capacitive proximity sensor device having the electrode arrangement shown in FIG. Sensor outputs in the X-axis direction and Y-axis direction at this time are also shown in FIG.

As can be seen from FIG. 5C, in the electrode arrangement shown in FIG. 2, there is a separation portion (reference numeral 13o in FIG. 2) at the center of each of the four sides of the reference surface (sensor surface). The separation portion 13e is the closest portion to drive and detection, and is a portion with high sensitivity. For this reason, the sensitivity is improved when a hand is brought close to the top, bottom, left, and right. However, since the sensor output is rotated 45 degrees as in the case of the electrode arrangement in the conventional sensor (FIG. 6A), the rotation is performed on the respective sensor outputs X ₁ and Y ₁ in the X-axis direction and the Y-axis direction. Need to add. Therefore, FIG. 5D shows the result of adding rotation to the sensor outputs X ₁ and Y ₁ as in the above equation. In FIG. 5D, the sensor output in the X-axis direction is indicated by X ₁ ′, and the sensor output in the Y-axis direction is indicated by Y ₁ ′.

  6 (a) and 6 (b) are diagrams for explaining the detection state of a conventional capacitive proximity sensor device. FIG. 6A shows a state where the hand, which is the detection object, is placed on the right side in the capacitive proximity sensor device in which the electrodes are arranged along the four sides of the reference surface (sensor surface). FIG. 6C shows sensor outputs in the X-axis direction and the Y-axis direction at this time. FIG. 6B shows a state in which the hand that is the detection object is placed in the center in the capacitive proximity sensor device in which the electrodes are arranged along the four sides of the reference surface (sensor surface). . Sensor outputs in the X-axis direction and Y-axis direction at this time are also shown in FIG.

As can be seen from FIG. 6 (c), the in the state shown in FIG. 6 (a), the output of the sensor output X ₂ it is possible to cover almost the electrode 101d by hand 31 is greatly changed, and FIG. 6 (b) In the state shown in FIG. ₂ , the sensitivity is greatly reduced (the sensor output Y2 is small) because only the vicinity of the center of the electrode 101a and the hand 31 are electrostatically coupled.

  FIG. 7 is a diagram illustrating the outputs of the capacitive proximity sensor device according to the embodiment of the present invention and the conventional capacitive proximity sensor device. As shown in FIG. 7, when the output values of the capacitive proximity sensor device according to the present invention and the conventional capacitive proximity sensor device are compared, the output increases more than twice when operated on the Y axis. I understand that. For this reason, the capacitive proximity sensor device according to the present invention can detect the hand more remarkably. Further, when the output range between the capacitive proximity sensor device according to the embodiment of the present invention and the conventional capacitive proximity sensor device was examined, it was as shown in FIG. The characteristic suitable for the cross key such as up / down / left / right was obtained. This is because the sensitivity in the Y-axis direction is improved because the sensitivity at the center position in the vertical and horizontal directions is improved.

  Thus, in the capacitive proximity sensor device according to the present invention, four electrodes each having a substantially L-shaped portion at each corner of a rectangular reference surface (sensor surface) along two adjacent sides. Therefore, the area to be coupled with the detected object is widened, the output can be increased at the center position of the sensor surface in the vertical and horizontal directions, and the detection can be performed with natural movement with respect to the operation of the detected object. it can. In addition, since the sensitivity at the center position of the top, bottom, left and right is improved, characteristics suitable for the cross key such as the top, bottom, left and right when operating with a human hand can be obtained.

  The present invention is not limited to the embodiment described above, and can be implemented with various modifications. In the said embodiment, it is possible to change suitably about the right and left, upper and lower sides, front-depth distinction, the numerical value of a member, a position, a magnitude | size, and a shape. Other modifications may be made as appropriate without departing from the scope of the object of the present invention.

  The present invention can be applied to various input devices such as a digital photo frame, a PC, and an audio operation panel.

DESCRIPTION OF SYMBOLS 11 Sensor part 12 Control circuit part 13 Sensor surface 13a-13d Electrode 14 Multiplexer 15 CPU
16 Drive Circuit 17 Detection Circuit 18 Amplification Circuit 19 A / D Converter 31 Detected Object

Claims (2)

  4 electrodes having substantially L-shaped portions arranged at respective corners of the reference surface along two adjacent sides in a rectangular reference surface having four sides and four corners; A drive circuit that applies a drive voltage using a pair of electrodes opposed in the diagonal direction of the reference plane among the two electrodes as a drive electrode, and a pair of detection electrodes that are opposed in the diagonal direction of the reference plane among the four electrodes And a detection circuit for detecting the detected signal.   The capacitive proximity sensor device according to claim 1, and a motion detection means for processing the position information of the detected object calculated by the arithmetic circuit with a predetermined time constant, and detecting a motion of the detected object; An electrostatic capacity type motion detection device comprising:

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