Input detection system

Abstract

To provide an input detection system that accurately detects input operations and is easy to use. [Solution] The input detection system 1 comprises a capacitance sensor 20, an input device 100, a detection circuit 80, and a control circuit 90. The input device 100 has at least one input key. The input key has a detection conductor, and the distance between the detection conductor and the insulating plate 30 on which the input device 100 is placed can be varied depending on how hard the key is pressed. The control circuit 90 outputs an input signal to the input device 100 based on the detection value output from the detection circuit 80, according to the distance between the detection conductor and the insulating plate 30.

Description

Technical Field

[0001] This disclosure relates to an input detection system.

Background Art

[0002] Patent Document 1 describes a keyboard for music. The thin keyboard of Patent Document 2 incorporates a switch circuit.

Prior Art Documents

Patent Documents

[0003]

Patent Document 2

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0004] The keyboard for music in Patent Document 1 has an integrated control device and the like, and there is a limit to thinning. The keyboard of Patent Document 2 is an input detection system incorporating a switch circuit, and the structure becomes complex.

[0005] An object of this disclosure is to provide an input detection system that can detect an input operation well and is easily usable.

Means for Solving the Problems

[0006] An input detection system according to one aspect of the present disclosure includes: a capacitance sensor disposed on one side of an insulating plate, having a plurality of detection electrodes disposed on a detection surface; an input device disposed on the other side of the insulating plate, having at least one input key having a detection conductor and capable of varying the distance between the detection conductor and the insulating plate in response to being pressed; a detection circuit connected to the capacitance sensor; and a control circuit that controls the capacitance sensor and the detection circuit, wherein the control circuit outputs an input signal to the input device based on a detection value output from the detection circuit, according to the distance between the detection conductor and the insulating plate. [Brief explanation of the drawing]

[0007] [Figure 1] Figure 1 is a schematic diagram showing the input device of Embodiment 1. [Figure 2] Figure 2 is an explanatory diagram illustrating the input detection system of Embodiment 1. [Figure 3] Figure 3 is a schematic diagram showing the capacitance sensor of Embodiment 1. [Figure 4] Figure 4 is an explanatory diagram illustrating the configuration of the capacitance sensor in Embodiment 1. [Figure 5] Figure 5 is a block diagram illustrating the configuration of the capacitance sensor in Embodiment 1. [Figure 6] Figure 6 is a schematic diagram showing the back surface of the input device of Embodiment 1. [Figure 7] Figure 7 is a schematic diagram showing the first operating state of the input key in Embodiment 1. [Figure 8] Figure 8 is a schematic diagram showing the second operating state of the input key in Embodiment 1. [Figure 9] Figure 9 is a flowchart showing an example of a detection method for the input detection system of Embodiment 1. [Figure 10] Figure 10 is a schematic diagram showing the input device of Embodiment 2. [Figure 11] Figure 11 is a schematic diagram showing the input device of Embodiment 3. [Modes for carrying out the invention]

[0008] The embodiments for implementing this disclosure will be described in detail with reference to the drawings. This disclosure is not limited to the embodiments described below. Furthermore, the components described below include those that can be easily conceived by a person skilled in the art, and those that are substantially the same. In addition, the components described below can be combined as appropriate. The disclosure is merely an example, and any modifications that a person skilled in the art can easily conceive while maintaining the spirit of this disclosure are naturally included within the scope of this disclosure. Furthermore, in order to make the explanation clearer, the drawings may schematically represent the width, thickness, shape, etc. of each part compared to the actual embodiment, but these are merely examples and do not limit the interpretation of this disclosure. Furthermore, in this disclosure and in each drawing, elements similar to those described above with respect to previously shown drawings are denoted by the same reference numerals, and detailed explanations may be omitted as appropriate.

[0009] In this disclosure, when describing a manner in which one structure is placed on top of another structure, unless otherwise specified, the term "on top of" includes both cases: when one structure is placed directly on top of another structure so as to be in contact with it, and when another structure is placed above another structure via yet another structure.

[0010] (Embodiment 1) Figure 1 is a schematic diagram showing the input device of Embodiment 1. Figure 2 is an explanatory diagram illustrating the input detection system of Embodiment 1. As shown in Figure 1, the input device 100 has an input key 10 in the housing 11. As shown in Figure 2, the input detection system 1 of Embodiment 1 includes a capacitance sensor 20, an insulating plate 30, and the input device 100. The input detection system 1 is arranged in the order of capacitance sensor 20, insulating plate 30, and input device 100, in a direction perpendicular to the surface of the capacitance sensor 20.

[0011] As shown in FIG. 2, the capacitance sensor 20 performs detection using the self-capacitance method. More specifically, the capacitance sensor 20 detects the position of the housing 11 and the position of the input key 10 in a state where the input key 10, which is the detection target, and the housing 11 are not in contact with the detection surface of the capacitance sensor 20. Alternatively, the capacitance sensor 20 detects the movement of the input key 10 in a state where the input device 100 having the input key 10 is not in contact with the detection surface of the capacitance sensor 20. A configuration example of the capacitance sensor 20 will be described later with reference to FIG. 2.

[0012] The insulating plate 30 is disposed on the capacitance sensor 20 and enables the installation of the input device 100. The insulating plate 30 is, for example, a plate-like member formed of an insulating material such as wood or a resin material. The insulating plate 30 only needs to be a plate-like member on which the input device 100 can be installed, and it may be a shelf, a table, or the like on which the input device 100 is placed.

[0013] Information is inputted by pressing the input key 10 of the input device 100. The input device 100 is a keyboard for voice that can play music from a speaker according to the inputted information.

[0014] FIG. 3 is a schematic diagram showing the capacitance sensor of Embodiment 1. As shown in FIG. 3, an electric field is generated in a direction perpendicular to the capacitance sensor 20 from the detection electrode 21 of the capacitance sensor 20, and an electric field is also generated around the input key 10 by capacitive coupling. As a result, a capacitance is formed, for example, between the human body and the input key 10 in response to the depression of the input key 10, which is the detection target. Consequently, the magnitude of the detection value obtained from the detection electrode 21 of the capacitance sensor 20 at the position overlapping with the input device 100 changes. Thereby, the input detection system 1 can detect the key pressing of the input key 10.

[0015] Further, the input detection system 1 does not need to directly connect the input device 100 to the electrode of the capacitance sensor 20, and there are few restrictions on the position where the input device 100 is placed on the insulating plate 30. Therefore, the appearance of the input detection system 1 is not impaired even when the capacitance sensor 20 is disposed.

[0016] As shown in FIG. 2, the input detection system 1 includes a detection circuit 80, a control circuit 90, a display unit 71, and a speaker 72. The detection circuit 80 and the control circuit 90 are mounted on a wiring board 89 connected to the capacitance sensor 20. The wiring board 89 is, for example, a flexible printed circuit (FPC) or a rigid printed circuit board (PCB).

[0017] The detection circuit 80 is connected to a plurality of detection electrodes 21 (see FIG. 3) of the capacitance sensor 20. The detection circuit 80 acquires detection values from the plurality of detection electrodes 21, performs predetermined signal processing, and outputs the results to the control circuit 90. The control circuit 90 controls the capacitance sensor 20. The control circuit 90 includes, for example, a micro control unit (MCU).

[0018] A processing device 110 (external processing device) and a power supply 60 are connected to the control circuit 90. The processing device 110 functions as a host computer (HOST) of the input detection system 1. The processing device 110 includes a central processing unit (CPU) and a storage circuit 111 such as a memory, and controls the operations of the display unit 71 and the speaker 72 by executing a program using these hardware resources. For example, the processing device 110 controls the operations of the display unit 71 and the speaker 72 based on the detection results of the detected object by the detection circuit 80 and the control circuit 90. In FIG. 2, the processing device 110 controls the operations of the display unit 71 and the speaker 72, but the present invention is not limited thereto, and the control circuit 90 may control the operations of the display unit 71 and the speaker 72.

[0019] The power supply 60 supplies a power supply voltage to each of the detection circuit 80, the control circuit 90, and the processing device 110.

[0020] Figure 3 is a schematic diagram showing an example of the configuration of a capacitive sensor in the detection system according to Embodiment 1. As shown in Figure 3, the capacitive sensor 20 has a substrate 23, a plurality of detection electrodes 21 provided on the substrate 23, and peripheral electrodes 22. When the capacitive sensor 20 is operated alone, it is possible to perform both hover detection, which detects the position and movement of an object to be detected, such as a finger, when the object is not in contact with the detection surface of the capacitive sensor 20, and touch detection, which detects the position and movement of an object to be detected when the object is in contact with the detection surface of the capacitive sensor 20.

[0021] The hover detection mode of the capacitive sensor 20 includes detecting the position and movement of the object being detected when it is not in contact with the object. The touch detection mode also includes detecting the position and movement of the object being detected when it is in contact with the object.

[0022] The capacitance sensor 20 performs detection using a self-capacitance method. Since the capacitance sensor 20 is highly sensitive enough to detect hovering, as shown in Figure 2, the capacitance sensor 20 can detect the operation of the input key 10 even if there is an insulating plate 30 between the capacitance sensor 20 and the input device 100 which is the object to be detected.

[0023] In the following explanation, the first direction Dx is a direction in the plane parallel to the substrate 23. The second direction Dy is a direction in the plane parallel to the substrate 23 and is perpendicular to the first direction Dx. The second direction Dy may intersect the first direction Dx without being perpendicular to it. The third direction Dz is a direction perpendicular to both the first direction Dx and the second direction Dy and is the normal direction to the main surface of the substrate 23. Furthermore, "plan view" refers to the positional relationship when viewed from a direction perpendicular to the substrate 23.

[0024] As shown in Figure 3, the capacitance sensor 20 has a detection region SA and a peripheral region BE outside the detection region SA. The detection region SA is the region where the detection electrode 21 is provided and is the region for detecting an object to be detected that is close to the detection surface. The peripheral region BE is the region outside the detection region SA where the detection electrode 21 is not provided and is the region where peripheral electrodes 22 are provided along the four sides of the detection region SA. In this disclosure, the detection region SA is larger than the area of ​​the input device 100 as seen from the third direction Dz (in a plan view). If the detection region SA is larger than the installation area of ​​the input device 100, the area on the insulating plate 30 in which the input key 10 of the input device 100 can be detected becomes larger, making it easy to use simply by placing it on the insulating plate 30.

[0025] Multiple detection electrodes 21 are arranged planarly on the detection area SA of the substrate 23, and are arranged in a matrix in a planar view. In other words, the multiple detection electrodes 21 are arranged side by side in the first direction Dx and the second direction Dy. Each of the multiple detection electrodes 21 is electrically connected to the detection circuit 80 via wiring (not shown).

[0026] The peripheral electrode 22 is arranged to surround the plurality of detection electrodes 21 provided in the detection region SA. The peripheral electrode 22 and the detection electrodes 21 are electrodes arranged side by side on the substrate 23. In the capacitance sensor 20 of Embodiment 1, the peripheral electrode 22 may be omitted. Also, the capacitance sensor 20 may have a shield electrode 24 (see Figure 4) provided on the side of the substrate 23 opposite to the side on which the detection electrodes 21 and peripheral electrode 22 are provided.

[0027] Figure 4 is an explanatory diagram illustrating the configuration of the capacitance sensor of Embodiment 1. As shown in Figure 4, in addition to the capacitance sensor 20, detection circuit 80 and control circuit 90 described above, the input detection system 1 includes a first power supply circuit 96 (POW1), a second power supply circuit 84 (POW2), a drive signal generation circuit 97, a first isolator 51, a second isolator 52, and an isolated DC-DC converter 53.

[0028] In this disclosure, the processing unit 110, the control circuit 90, the first power supply circuit 96, and the drive signal generation circuit 97 are included in the first reference potential block 41. In this disclosure, the second power supply circuit 84, the detection circuit 80, and the capacitance sensor 20 are included in the second reference potential block 42. The processing unit 110, the control circuit 90, the first power supply circuit 96, and the drive signal generation circuit 97 included in the first reference potential block 41 operate with the first reference potential GND1, which is a fixed potential, as the ground potential. The second power supply circuit 84, the detection circuit 80, and the capacitance sensor 20 included in the second reference potential block 42 operate with the second reference potential GND2, which is generated by the drive signal generation circuit 97, as the ground potential.

[0029] The first power supply circuit 96 converts the power supplied via the USB cable's power line VBUS into a voltage and supplies it to the control circuit 90 and the drive signal generation circuit 97.

[0030] The isolated DC-DC converter 53 provides isolation and power transmission between the processing unit 110 and the second power supply circuit 84. The isolated DC-DC converter 53 performs power transmission using a magnetic isolation method.

[0031] The isolated DC-DC converter 53 receives power from the power line VBUS of the USB cable to the coil on the first reference potential block 41, which then generates a magnetic field. The coil on the second reference potential block 42 is located within the range of influence of the magnetic field generated by the coil on the first reference potential block 41.

[0032] An induced electromotive force is generated in the coil on the second reference potential block 42 side, corresponding to the magnetic field generated by the coil on the first reference potential block 41 side. The power generated in the coil on the second reference potential block 42 side is supplied to the second power supply circuit 84.

[0033] The second power supply circuit 84 converts the power supplied from the isolated DC-DC converter 53 into a voltage and supplies it to the detection circuit 80.

[0034] The detection circuit 80 generates a rectangular wave signal Tx as a periodic fluctuating potential with a periodic potential fluctuation pattern. The rectangular wave signal Tx includes the fundamental frequency component and harmonic component of the drive signal supplied to the peripheral electrode 22 and shield electrode 24 of the capacitance sensor 20.

[0035] Furthermore, the detection circuit 80 acquires sensing data from multiple detection electrodes 21 and outputs it to the control circuit 90 via the first isolator 51.

[0036] In this disclosure, signals between the detection circuit 80 and the control circuit 90 are transmitted via a clock-synchronous serial interface, which is called SPI (Serial Peripheral Interface). However, the serial interface for transmitting signals between the detection circuit 80 and the control circuit 90 is not limited to SPI.

[0037] The first isolator 51 provides isolation and signal transmission between the control circuit 90 and the detection circuit 80. The electrical signals input and output via the first isolator 51 are synchronized between the control circuit 90 and the detection circuit 80.

[0038] The second isolator 52 provides isolation between the detection circuit 80 and the drive signal generation circuit 97 and transmits the square wave signal Tx. The square wave signal Tx input and output via the second isolator 52 is synchronized between the detection circuit 80 and the drive signal generation circuit 97.

[0039] The second isolator 52 performs signal transmission using an optical isolation method, for example, a photocoupler. The signal transmission method between the control circuit 90 and the detection circuit 80 in the first isolator 51 may be the same as that of the second isolator 52, or it may be a different method. In other words, the first isolator 51 may be an optical isolation photocoupler, or a magnetic isolation digital isolator similar to that of the isolated DC-DC converter 53.

[0040] The first isolator 51 is capable of bidirectional signal transmission, both from the control circuit 90 to the detection circuit 80 and from the detection circuit 80 to the control circuit 90. In a configuration using an optically isolated photocoupler as the first isolator 51, a photocoupler that transmits signals from the control circuit 90 to the detection circuit 80 and a photocoupler that transmits signals from the detection circuit 80 to the control circuit 90 are connected in parallel.

[0041] The control circuit 90 transmits various information and signals such as control commands related to sensing data (detected values) to the processing unit 110.

[0042] Furthermore, the control circuit 90 outputs an electrical resistance value setting command to the digital potentiometer, based on reference information (DP control reference data) that shows the correspondence between the fundamental frequency of the square wave signal Tx output from the detection circuit 80 and the electrical resistance value of the digital potentiometer (not shown) possessed by the drive signal generation circuit 97. The command sets the electrical resistance value of the digital potentiometer to an electrical resistance value corresponding to the fundamental frequency of the square wave signal Tx output from the detection circuit 80. As a result, the electrical resistance value of the digital potentiometer is controlled to an electrical resistance value corresponding to the fundamental frequency of the square wave signal Tx.

[0043] Furthermore, the control circuit 90 performs noise detection processing on the sensing data and position determination (coordinate calculation processing) of the detected object based on the sensing data. Noise detection processing is performed to determine the amount of noise components contained in the sensing data (detected value). Coordinate calculation processing is performed to determine the position of the detected object (or the detected object in close proximity to the capacitance sensor 20). Specifically, in the coordinate calculation processing, for example, the position in the first direction Dx, the position in the second direction Dy, and the position in the third direction Dz (see Figure 3) of the detected object in close proximity to the capacitance sensor 20 can be derived. Note that the coordinate calculation processing includes calculation processing performed to determine the position of the input device 100 installed on top of the capacitance sensor 20. Since the details of the noise detection processing and coordinate calculation processing are the same as those known, a detailed explanation is omitted.

[0044] In this disclosure, signals between the control circuit 90 and the processing unit 110 are transmitted via a serial interface, namely USB. Specifically, signals between the control circuit 90 and the processing unit 110 are transmitted via the signal lines D+ and D- of the USB cable. However, the serial interface for transmitting signals between the control circuit 90 and the processing unit 110 is not limited to USB.

[0045] In the configuration described above, the first reference potential block 41, which includes the processing unit 110, the control circuit 90, the first power supply circuit 96, and the drive signal generation circuit 97, and the second reference potential block 42, which includes the second power supply circuit 84, the detection circuit 80, and the capacitance sensor 20, are electrically isolated from each other via an isolated DC-DC converter 53, a first isolator 51, and a second isolator 52.

[0046] Furthermore, the first reference potential GND1, which is provided to the first reference potential block 41 as the ground potential, is a fixed potential held by a large electrode, such as a solid electrode. On the other hand, the second reference potential GND2, which is provided to the second reference potential block 42 as the ground potential, is a periodically fluctuating potential generated by the drive signal generation circuit 97.

[0047] In the input detection system 1 according to this disclosure, the fluctuation period of the periodically fluctuating potential (second reference potential GND2) is the same as the generation period of the square wave generated by the detection circuit 80 (square wave period of the square wave signal Tx). In other words, the second reference potential GND2 is a potential that fluctuates periodically in synchronization with the square wave signal Tx generated by the detection circuit 80.

[0048] Figure 5 shows an example of a functional circuit block configuration for a detection circuit and a control circuit.

[0049] As shown in Figure 5, the detection circuit 80 includes a readout circuit 81, an ADC (Analog Digital Converter) circuit 82, and a DSP (Digital Signal Processor) circuit 83. Each circuit element of the detection circuit 80 operates with the second reference potential GND2, which is a periodically fluctuating potential generated by the drive signal generation circuit 97, as the ground potential.

[0050] The readout circuit 81 acquires a detection signal Rx from each of the detection electrodes 21. The readout circuit 81 is, for example, an analog front-end circuit (AFE).

[0051] The ADC circuit 82 converts the detection signal Rx acquired by the readout circuit 81 from an analog signal to a digital signal.

[0052] The DSP circuit 83 performs digital filtering on the digital data converted into a digital signal by the ADC circuit 82 to generate a detection signal Rx.

[0053] The detection circuit 80 outputs the sensing data (detected value) generated by the DSP circuit 83 to the control circuit 90 via the first isolator 51.

[0054] The control circuit 90 includes a read circuit 91, a noise detection circuit 92, a coordinate calculation circuit 93, a memory circuit 94, and a determination circuit 95. Each circuit element of the control circuit 90 operates with a fixed potential, the first reference potential GND1, as the ground potential.

[0055] The reading circuit 91 acquires the sensing data (detected value) output from the detection circuit 80 via the first isolator 51.

[0056] The noise detection circuit 92 performs noise detection processing based on the sensing data (detected value) acquired by the reading circuit 91.

[0057] The coordinate calculation circuit 93 performs coordinate calculation processing based on the sensing data (detected values) acquired by the reading circuit 91.

[0058] The memory circuit 94 has pre-stored various thresholds (first threshold and second threshold) for determining whether the input key 10 is pressed and the position of the input device 100.

[0059] The determination circuit 95 compares the sensing data (detected value) acquired by the reading circuit 91 with the first threshold or second threshold held in the storage circuit 94 to determine whether or not the input device 100 is present.

[0060] Furthermore, the control circuit 90 has the function of changing the fundamental frequency of the square wave signal Tx output from the detection circuit 80. When the fundamental frequency of the square wave signal Tx output from the detection circuit 80 is changed, the control circuit 90 resets the electrical resistance value of the digital potentiometer in the drive signal generation circuit 97 according to the changed fundamental frequency of the square wave signal Tx.

[0061] The control circuit 90 has the function of changing the fundamental frequency of the square wave signal Tx output from the detection circuit 80.

[0062] Figure 6 is a schematic diagram showing the back surface of the input device of Embodiment 1. Figure 7 is a schematic diagram showing the first operating state of the input key of Embodiment 1. Figure 8 is a schematic diagram showing the second operating state of the input key of Embodiment 1.

[0063] As shown in Figure 6, the housing 11 has a plurality of reference conductors 15 on the back side of the input device 100, which is in contact with the insulating plate 30. The input key 10 has a detection conductor 13 on its back side.

[0064] The memory circuit 111 (see Figure 2) of the processing unit 110 stores in advance the relative positional relationships between multiple reference conductors 15 and detection conductors 13.

[0065] Furthermore, when the housing 11 of the input device 100 moves relative to the capacitance sensor 20 (see Figure 2), the detection electrode 21 of the capacitance sensor 20 (see Figure 2) at the position overlapping with the reference conductor 15 of the input device 100 changes. As a result, the input detection system 1 shown in Figure 2 can detect that the input device 100 has moved on the insulating plate 30.

[0066] In Embodiment 1, the parasitic capacitance can be adjusted so that the sensing data (detected value) of the reference conductor 15 does not become saturated by appropriately adjusting the thickness of the insulating plate 30 shown in Figure 2.

[0067] Figures 7 and 8 show an example of an input key 10. The input device 100 has a housing 11, an input key 10, and a pivot point 14. The input key 10 has a key top 16 and a protrusion 12 that projects downward from the key top 16. The key top 16 and the protrusion 12 are molded from an insulating resin. The detection conductor 13 is a foil body made of a conductor such as copper or aluminum. An insulating plate 30 is placed between the capacitance sensor 20 and the detection conductor 13.

[0068] The pivot point 14 is a pin or the like. The pivot point 14 does not allow the key top 16 to move up, down, left, or right, but it fixes the key top 16 to the housing 11 so that it can rotate freely around the pivot point 14. As shown in Figure 7, in the first operating state, the human body 99 is not pressing down on the input key 10. Therefore, the distance between the capacitive sensor 20 and the detection conductor 13 is increased. Also, in the first operating state, the capacitance of the human body 99 is not coupled with the detection conductor 13.

[0069] As shown in Figure 8, in the second operating state, the human body 99 is pressing down on the input key 10. As a result, the distance between the capacitance sensor 20 and the detection conductor 13 becomes smaller. In the second operating state, the capacitance of the human body 99 is coupled with the detection conductor 13.

[0070] Next, the detection method of the input detection system 1 will be described with reference to Figure 9. Figure 9 is a flowchart showing an example of the detection method of the input detection system of Embodiment 1.

[0071] As shown in Figure 9, the input detection system 1 starts detection using the capacitance sensor 20 (step ST11). The detection circuit 80 acquires detection signals Rx from each detection electrode 21 when the input device 100 is not on the insulating plate 30, and the control circuit 90 generates baseline data based on the detection signals Rx and stores it in the memory circuit 94 (step S12). The determination circuit 95 generates a first threshold value based on the baseline data and stores it in the memory circuit 94.

[0072] The thicker the insulating plate 30, the smaller the absolute value of the detected value becomes. Since the first threshold is set according to the baseline data, the input key 10 of the input device 100 can be detected regardless of the thickness of the insulating plate 30.

[0073] The input detection system 1 starts detection using the capacitance sensor 20 (step ST13). The determination circuit 95 of the control circuit 90 compares the sensing data (detected value) obtained from the detection electrode 21 of the capacitance sensor 20 with a first threshold value previously stored in the memory circuit 94 (step ST14). If the sensing data (detected value) is smaller than the first threshold value (step ST14, No), detection using the capacitance sensor 20 for the first scan continues (step ST13).

[0074] If the sensing data (detected value) is greater than or equal to the first threshold (step ST14, Yes), the determination circuit 95 of the control circuit 90 calculates the first coordinates, which are the positions of the multiple reference conductors 15 of the input device 100, via the insulating plate 30 on the capacitance sensor 20 (step ST15).

[0075] Based on the first coordinates, the position coordinates of the reference conductor 15 of the input device 100 are determined (step ST16).

[0076] The input detection system 1 starts detection using the capacitance sensor 20 (step ST17). The determination circuit 95 of the control circuit 90 compares the sensing data (detected value) obtained from the detection electrode 21 of the capacitance sensor 20 with a second threshold value previously stored in the memory circuit 94 (step ST18). If the sensing data (detected value) is smaller than the second threshold value (step ST18, No), detection using the capacitance sensor 20 for the second scan continues (step ST17).

[0077] If the sensing data (detected value) is greater than or equal to the second threshold (step ST18, Yes), the determination circuit 95 of the control circuit 90 calculates a second coordinate which is the position of at least one detection conductor 13 of the input device 100 via the insulating plate 30 on the capacitance sensor 20 (step ST19).

[0078] Based on the second coordinate system, the position coordinates of the detection conductor 13 of the input device 100 are determined (step ST20). This determines the input position of the input key 10 that has been operated.

[0079] Based on the input position of the input key 10 for a specific input operation, i.e., the second coordinate, the processing unit 110 executes the assigned process (step ST21). The input detection system 1 operates the display unit 71 and the speaker 72 according to the assigned process.

[0080] If the input operation of the input detection system 1 is completed (step ST22, Yes), the input detection system 1 terminates its sensing operation. Examples of cases in which the sensing operation terminates include when the power supply to the input detection system 1 is stopped, or when the processing unit 110 outputs a command to the input detection system 1 to terminate the sensing operation. If the input operation of the input detection system 1 is not completed (step ST22, No), the operations from step ST17 onward are repeatedly executed.

[0081] As described above, the input device 100 has a detection conductor 13 and at least one input key 10 that can vary the distance between the detection conductor 13 and the insulating plate 30 in response to being pressed. The input detection system 1 includes a capacitance sensor 20 on one side of the insulating plate 30, on which a plurality of detection electrodes 21 are arranged on the detection surface; the input device 100 on the other side of the insulating plate 30; a detection circuit 80 connected to the capacitance sensor 20; and a control circuit 90 that controls the capacitance sensor 20 and the detection circuit 80. The control circuit 90 outputs an input signal to the input device 100 based on the detection value output from the detection circuit 80, according to the distance between the detection conductor 13 and the insulating plate 30. As a result, the input detection system 1 of the embodiment can operate various devices such as the display unit 71 and the speaker 72 using the pressing of the input key 10 as a trigger. The input detection system 1 accurately detects input operations. The input device 100 can be made thinner and can be easily used simply by placing it on the insulating plate 30.

[0082] The input detection system 1 includes a processing unit 110 connected to a control circuit 90. The input device 100 is equipped with a plurality of reference conductors 15 on the insulating plate 30 side. The processing unit 110 stores the relative positions of the plurality of reference conductors 15 and the detection conductor 13 as map information in a memory circuit 111. The processing unit 110 identifies the positions of the plurality of reference conductors 15 based on the detection values ​​output from the control circuit 90. In this way, the processing unit 110 determines that the input device 100 has been placed on the insulating plate 30 when a detection value equal to or greater than a first threshold is input and matches the map information.

[0083] Note that the operation of the display unit 71 and speaker 72 shown in Figure 11 is merely an example, and the detection results of the detected object and input device 100, and the operation of the display unit 71 and speaker 72 can be combined in any way. The input detection system 1 does not need to have both the display unit 71 and speaker 72; it is sufficient to have at least one of them. Alternatively, the input detection system 1 may include other devices in addition to the display unit 71 and speaker 72.

[0084] (Embodiment 2) Figure 10 is a schematic diagram showing the input device of Embodiment 2. The input device 100A has input keys 10A. The input device 100A is an information input keyboard in which information is input by pressing the input keys 10A. The processing device 110 processes the input information of the input device 100A according to the information, and displays the processing result on the display unit 71.

[0085] (Embodiment 3) Figure 11 is a schematic diagram showing the input device of Embodiment 3. The input device 100B has input keys 10B. The input device 100B is a numeric keypad into which numerical information is input by pressing the input keys 10B. The processing device 110 processes the input information of the input device 100B according to the information, and displays the processing result on the display unit 71.

[0086] While preferred embodiments of this disclosure have been described above, this disclosure is not limited to such embodiments. The contents disclosed in the embodiments are merely examples, and various modifications are possible without departing from the spirit of this disclosure. Any modifications made without departing from the spirit of this disclosure will naturally fall within the technical scope of this disclosure. At least one of various omissions, substitutions, and modifications of components can be made without departing from the gist of each embodiment and each modification described above. [Explanation of Symbols]

[0087] 1. Input detection system 10, 10A, 10B Input Keys 11 cabinets 12 Convex part 13. Conductive material for detection 14 Fulcrum 15. Reference Conductor 16 keycaps 20 Capacitive Sensors 21 Detection electrode 23 circuit boards 24 Shielding electrodes 30 Insulating board 53 Isolated DC-DC Converter 60 power supply 71 Display section 72 speakers 80 Detection Circuit 89 Wiring board 90 Control circuits 92 Noise detection circuit 93 Coordinate Calculation Circuit 94,111 Memory circuit 95 Judgment circuit 97 Drive signal generation circuit 99 human body 100, 100A, 100B Input Device 110 Processing Unit

Claims

1. A capacitance sensor in which multiple detection electrodes are arranged on the detection surface, with the detection surface being arranged on one side of an insulating plate, An input device having at least one input key disposed on the other side of the insulating plate, having a detection conductor, and capable of varying the distance between the detection conductor and the insulating plate in response to being pressed, A detection circuit connected to the aforementioned capacitance sensor, The system includes a control circuit that controls the capacitance sensor and the detection circuit, The control circuit outputs an input signal to the input device based on the detected value output from the detection circuit, according to the distance between the detection conductor and the insulating plate. Input detection system.

2. The processing unit is connected to the control circuit, The insulating plate side of the input device is provided with a plurality of reference conductors, The processing apparatus has in advance stored the relative positions of the plurality of reference conductors and the detection conductor, The processing device identifies the positions of the plurality of reference conductors based on the detected values ​​output from the control circuit. The input detection system according to claim 1.

3. When the processing device receives a detected value equal to or greater than a first threshold, it determines that the input device is installed on the insulating plate. The input detection system according to claim 2.

4. When the processing device receives a detection value equal to or greater than a second threshold value at the coordinates of the reference conductor, it executes a process that assigns a specific input operation corresponding to the detection value at the coordinates of the reference conductor. The input detection system according to claim 3.

5. Furthermore, it has a speaker, The processing unit outputs sound from the speaker as the specific input operation. The input detection system according to claim 4.

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