JP2014075069A - On-vehicle touch panel input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an in-vehicle touch panel input device that can detect an input operation from a driver seat side and a passenger seat side without changing the structure of the touch panel input device by using a detection electrode for detecting an input operation position.
A plurality of detection electrodes arranged in the vicinity of an input operation area, and a capacitance detection means for detecting a capacitance level representing the capacitance between the detection electrode and the input operator's finger for each detection electrode And detecting the capacitance level detected for each detection electrode, and when the arrangement position of the detection electrode where the increase in the capacitance level is detected is moved from the passenger seat side to the driver seat side, Judged as an input operation.
[Selection] Figure 9

Description

  The present invention relates to an in-vehicle touch panel input device that is mounted in front of a driver seat and a passenger seat in a vehicle in order to operate an in-vehicle electronic device such as a car navigation device, and more particularly, while the vehicle is traveling. The present invention relates to an in-vehicle touch panel input device that accepts only an input operation from a passenger seat.

  In-vehicle electronic devices used in vehicles such as car navigation devices, audio equipment, video information devices such as televisions, etc., the operator enters the input operation area of the in-vehicle touch panel input device stacked on the display panel that displays the operation contents. An input operation for approaching or pressing the finger is performed, and the operation content displayed at the input operation position is executed. The input operation to this in-vehicle touch panel input device is attached to the center console section between the driver seat and the passenger seat in front of the vehicle so that both passengers in the driver seat and the passenger seat can operate. Yes.

  However, while the vehicle is traveling, it is dangerous for the driver to perform an input operation to the in-vehicle touch panel input device while looking at the operation content. Therefore, the invalidation or prohibition process is performed even if the input operation is performed. There was an inconvenience that even a passenger in the seat could not perform input operations. Therefore, conventionally, an input device for determining an input operation to an input operation by an occupant on the driver's seat side and the passenger's seat side and an in-vehicle electronic device including the input device are known.

  The car navigation device 100 shown in FIG. 14 is a set of near infrared rays arranged on the driver's seat side and the passenger seat side around the display device 102 on which the touch panel 101 for performing an input operation to the car navigation device 100 is overlaid. Sensor 103A, 103B discriminate | determines the input operation to the input operation by the passenger | crew of the driver's seat side and the passenger seat side (patent document 1). Each of the near-infrared sensors 103A and 103B includes an infrared light-emitting element and an infrared light-receiving element. For example, when an occupant in the passenger seat attempts to perform an input operation on the touch panel 101, the near-infrared sensor 103A disposed on the passenger seat side Infrared light reflected by the finger or hand performing the input operation is received, and the input operation is discriminated from the passenger seat side.

  The in-vehicle device described in Patent Document 2 is provided with a directional ultrasonic sensor that can move toward a driver seat and a passenger seat around a display device on which touch sensors are attached. From the direction of the ultrasonic sensor when the ultrasonic wave reflected by the finger or arm of the operator who wants to input the sensor is detected, it is determined whether the input operation is from the driver seat side or the passenger seat side.

  The car navigation device described in Patent Literature 3 registers only the fingerprint of the passenger's finger in the passenger seat, and the fingerprint sensor arranged in the vicinity of the input device detects a fingerprint that matches the registered fingerprint. The input operation to the device is made effective and only the input operation of the passenger in the passenger seat is possible.

  The on-vehicle display control device described in Patent Document 4 is provided with a key input control circuit that prohibits an input operation to the input device while the vehicle is running, and at a position that cannot be operated from the driver's seat side. A switch for canceling the prohibition state is attached, and even when the vehicle is traveling, the passenger in the passenger seat operates the switch to enable input operation to the input device.

JP 2006-64547 A

Japanese Patent No. 4984748

JP 2007-132678 A

JP-A-5-164565

  In the on-vehicle electronic device described in Patent Document 1 and Patent Document 2 described above, a sensor such as a near-infrared sensor or a sandwiched directional ultrasonic sensor is attached separately from the display device and the input device, so that the configuration is complicated. In addition, the cost increases, and when an existing display device or input device is used, the structure must be modified.

  In addition, since the sensors are arranged around the display device away from the input position where the input operation is performed, with a set of sensors or a sensor that only changes the direction from one point to the driver side and the passenger side, It is difficult to detect all input operations and determine their directions. If there is an area that cannot be detected in this way, the driver who is prohibited from performing the input operation while the vehicle is driving searches for an input operation direction that is not detected by the sensor due to annoyance, and the driver performs the input operation even while the vehicle is driving. There is a risk of making it possible. On the other hand, in order to detect input operations in all input operation directions with certainty, it is necessary to arrange a large number of sensors, which is expensive and the apparatus becomes large.

  Further, the car navigation device described in Patent Document 3 requires devices for reading, registering, and discriminating fingerprints, and the cost increases as the configuration becomes more complicated than the arrangement of sensors. Furthermore, the passenger in the passenger seat needs to press the finger against the fingerprint sensor every time the fingerprint registration procedure is performed and the input device is input, which is extremely troublesome.

  In addition, with respect to the in-vehicle display control device described in Patent Document 4, the passenger in the passenger seat has the trouble of operating the switch that releases the prohibited state of the key input control circuit each time an input operation is performed on the input device. Further, if the passenger in the passenger seat who rides operates the switch, there is a problem that the driver who is driving can also perform an input operation to the input device.

  The present invention has been made in consideration of such conventional problems, and uses the detection electrode for detecting the input operation position, and without changing the structure of the touch panel input device, the driver's seat side and the assistant An object of the present invention is to provide a vehicle-mounted touch panel input device that can determine an input operation from the seat side.

  It is another object of the present invention to provide an in-vehicle touch panel input device that discriminates an input operation from the driver's seat side and the passenger's seat side using a detection electrode disposed in the vicinity of the input operation area in which the operator's fingertip approaches. .

In order to achieve the above-described object, the in-vehicle touch panel input device according to claim 1 operates on the in-vehicle electronic device in front of the driver seat and the passenger seat in the vehicle in order to operate the in-vehicle electronic device. A plurality of detection electrodes that are attached to be overlapped above the display panel for guiding and displaying, and are arranged in an insulating manner in the vicinity of the input operation area that is set to overlap the display panel, and for each detection electrode, Capacitance detection means for detecting a capacitance level representing the capacitance between the detection electrode and the input operator's finger, and the capacitance level for any one or more detection electrodes detected by the capacitance detection means is predetermined. The input operation detection means for detecting the input operation to the input operation area and the side of the driver's seat or the passenger's seat in the vehicle determines whether the input operation has been performed to the input operation area. Direction discriminating means An in-vehicle touch panel input device that enables only the input operation determined by the direction determination means to be the input operation from the passenger seat side when the input operation detection means detects the input operation while the vehicle is running. ,
The direction discriminating unit monitors the capacitance level detected for each detection electrode while the input operation detecting unit detects the input operation, and the position of the detection electrode where the increase in the capacitance level is detected is driven from the passenger seat side. When moving to the seat side, it is determined that the input operation is from the passenger seat side.

  The capacitance Cm between the detection electrode and the input operator's finger is Cm = ε · s /, where d is the distance between them, ε is the dielectric constant of the air between them, and s is the opposing area between the detection electrode and the finger. The capacitance level represented by d and representing the capacitance Cm detected by the capacitance detection means is inversely proportional to the distance d between the detection electrode and the input operator's finger. Therefore, when the fingertip of the input operator approaches a specific detection electrode arranged in the vicinity of the input operation area, the capacitance level detected by the capacitance detection means for that detection electrode exceeds a predetermined input threshold value, and the input operation Is detected. When an input operation is performed from the passenger seat side, the fingertip of the input operator approaches the detection electrodes arranged in the order from the passenger seat side to the driver seat side. When moving from the passenger seat side to the driver seat side, it can be determined that the input operation is from the passenger seat side.

  The on-vehicle touch panel input device according to claim 2 detects the input operation position to the input operation area from the capacitance level detected by the capacitance detection means for any one or more detection electrodes and the arrangement position of the detection electrodes. The input position detecting means is further provided, and the input operation position detected by the input position detecting means is output only for the input operation determined by the direction determining means as the input operation from the passenger seat side.

  Since the capacitance level representing the capacitance Cm is inversely proportional to the distance d between the detection electrode and the input operator's finger, the input position detection means detects the relative position between each detection electrode and the fingertip from the capacitance level detected for each detection electrode. The input operation position where the fingertip is closest to the input operation area can be detected by comparing the distances. The input operation position detected by the input position detection unit is output only when the direction determination unit determines that the input operation is from the passenger seat side.

  The in-vehicle touch panel input device according to claim 3 further includes a seating sensor for detecting the seating of the passenger in the passenger seat, and the direction determining means is only when the seating sensor detects the seating of the passenger in the passenger seat. The input operation is determined from the passenger seat side.

  When a passenger is not seated in the passenger seat, it is possible to reliably prohibit an input operation by the driver while the vehicle is traveling.

The in-vehicle touch panel input device according to claim 4 is provided above the display panel for guiding and displaying the operation to the in-vehicle electronic device in front of the driver seat and the passenger seat in the vehicle in order to operate the in-vehicle electronic device. And a plurality of detection electrodes that are arranged in a distributed manner in the vicinity of the input operation area set over the display panel, and for each detection electrode, the detection electrode and the input operator's finger Capacitance detection means for detecting a capacitance level representing the capacitance of the input and the capacitance detection means detects an input operation to the input operation area from the capacitance level detected for any one or more detection electrodes. Input position detection for detecting the input operation position to the input operation area from the input operation detection means and the capacitance level detected for any one or more detection electrodes by the capacitance detection means and the arrangement position of the detection electrodes And a direction discriminating means for discriminating whether an input operation has been made to the input operation area from either the driver seat or the passenger seat in the vehicle, and the input operation detecting means performs the input operation while the vehicle is traveling. When detecting, an in-vehicle touch panel input device that outputs the input operation position detected by the input position detection means only for the input operation determined by the direction determination means as the input operation from the passenger seat side,
The direction discriminating means has a surface area along the input operation region that is substantially the same area, and is composed of a first or more detection electrodes that are arranged on the driver seat side at the symmetric position at the input operation position detected by the input position detection means. A detection electrode group and a second detection electrode group consisting of one or more detection electrodes arranged on the passenger seat side are selected, and a first total sum of capacitance levels detected by the capacitance detection means for the first detection electrode group Thus, when the second sum of the capacitance levels detected by the capacitance detection means for the second detection electrode group is large, it is determined that the input operation is from the passenger seat side.

  The capacitance Cm between the detection electrode and the input operator's finger is Cm = ε · s /, where d is the distance between them, ε is the dielectric constant of the air between them, and s is the opposing area between the detection electrode and the finger. The capacitance level represented by d and representing the capacitance Cm detected by the capacitance detection means is inversely proportional to the distance d between the detection electrode and the input operator's finger. The finger of the input operator who performs the input operation from the passenger seat side is located above the input operation area that continues from the input operation position detected by the input position detection means to the passenger seat side, and is arranged from the input operation position to the passenger seat side. Approach the second detection electrode group. Since the surface areas along the input operation area of the first detection electrode group and the second detection electrode group are substantially equal, the direction determining means is a capacitance level for the first detection electrode group disposed on the opposite side of the input operator's finger. Since the second sum for the second detection electrode group approaching by the finger of the input operator is larger than the first sum of the above, it can be determined that the input operation is from the passenger seat side.

  The on-vehicle touch panel input device according to claim 5 further includes transmission means for transmitting an AC detection signal in which a relative potential varies between each detection electrode and the input operator's finger, and the capacitance detection means includes each detection The reception level of the AC detection signal appearing on each detection electrode is detected as a capacitance level via the capacitance between the electrode and the input operator's finger, and the input position detection means detects every two or more detection electrodes. The input operation position to the input operation area is detected by comparing the relative distance between the finger of the input operator and the arrangement position of the detection electrode based on the capacity level.

  The electrostatic capacitance Cm between the detection electrode and the input operator's finger is the distance between the detection electrode and the input operator's finger d, the dielectric constant of air between them, and the detection electrode and the input operator's fingertip. The counter area is represented by s, and Cm = ε · s / d.

  The reception level Vi of the AC detection signal detected by the signal detection means for each detection electrode can be regarded as being proportional to the capacitance Cm between the detection electrode and the finger of the input operator. The dielectric constant ε of the air between the fingertips is a known value, and the facing area s between the detection electrode and the input operator's finger is a substantially constant value. Therefore, the distance between each detection electrode and the input operator's finger Inversely proportional to d, the input position detection means sets the reception level Vi of the AC detection signal detected for each detection electrode as a capacitance level representing the capacitance Cm, and determines each detection electrode and the input operator's finger from the reception level Vi. The input operation position on the input operation area of the input operator's finger can be detected.

  The in-vehicle touch panel input device according to claim 6 further includes a seating sensor for detecting the seating of the passenger in the passenger seat, and the direction determining means is only when the seating sensor detects the seating of the passenger in the passenger seat. The input operation is determined from the passenger seat side.

  When an occupant is not seated in the passenger seat, it is possible to reliably prohibit the output of the input operation position by the driver's input operation while the vehicle is traveling.

  The in-vehicle touch panel input device according to claim 7 is characterized in that the in-vehicle electronic device is a car navigation device.

  An input operation from the driver while the vehicle is traveling to the car navigation device can be surely prohibited.

  According to the invention of claim 1, since the input operation direction to the input operation area is determined using the detection electrode and the capacitance detection means provided in the conventional capacitive touch panel input device, the existing touch panel is used. An in-vehicle touch panel input device that enables only an input operation from the passenger seat side without changing the physical structure of the input device can be obtained. Therefore, it is not necessary to provide another detection means for detecting the input operation direction such as a sensor.

  In addition, since the input operation direction can be determined from the capacitance level detected by the detection electrode arranged in the vicinity of the input operation area that is the target of the input operation, the input that causes the finger to approach the input operation area from the driver seat side or the passenger seat side The input operation direction of the operation can be reliably detected without any leakage.

  Further, the input operation direction toward the input operation position can be detected in the process of the input operation before the finger is brought close to the input operation position, and detection of the input operation position can be omitted for an input operation that is not determined to be valid.

  According to the second aspect of the present invention, the detection electrode, the capacitance detection means and the input position detection means provided in the conventional capacitive touch panel input device are used, and the vehicle is running without changing its structure. Thus, an in-vehicle touch panel input device capable of operating an in-vehicle electronic device by performing an input operation only by a passenger in the passenger seat is obtained.

  According to the invention of claim 3, the driver can prohibit an illegal input operation that is intentionally performed by extending a finger from the passenger seat side to the input operation area.

  According to the fourth aspect of the present invention, the detection electrode, the capacitance detection means and the input position detection means provided in the conventional capacitive touch panel input device are used, and the vehicle is running without changing its structure. An in-vehicle touch panel input device capable of operating an in-vehicle electronic device by performing an input operation only by a passenger in the passenger seat is obtained, and there is no need to provide another detection means for detecting an input operation direction such as a sensor. .

  In addition, the input operation direction is determined by comparing the sum of the capacitance levels detected by one or more detection electrodes arranged at symmetrical positions in the vicinity of the input operation position that is the target of the input operation. Thus, there is no detection leak as in the case of using the input operation, and the input operation direction of the input operation can be reliably detected without any loss.

  According to the fifth aspect of the present invention, since the input operation position is detected from the relative distance between each detection electrode and the input operator's finger, the input is made to contact the transparent input operation plate arranged along the input operation area. The input operation position can be detected not only for the operation but also for a non-contact input operation in which the input operation body only approaches the input operation area.

  Further, even if the base of the finger continuous from the fingertip is away from the input operation area, the direction of the finger base can be detected from the fingertip approaching the input operation position, and the input operation direction can be detected accurately.

  According to the invention of claim 6, the driver can prohibit the output of the input position by an unauthorized input operation intentionally performed by extending the finger from the passenger seat side to the input operation area.

  According to the seventh aspect of the present invention, it is possible to prevent dangerous driving by prohibiting an input operation from the driver during traveling of the vehicle to the car navigation device.

It is a partially broken top view of the vehicle-mounted touch panel input device 1 which concerns on 1st Embodiment of this invention. It is a side view of the vehicle-mounted touch panel input device 1 and the display panel 40 laminated | stacked up and down. It is a top view of the vehicle-mounted touchscreen input device 1 except the shield board 32. FIG. 1 is a block diagram of an in-vehicle touch panel input device 1. FIG. 3 is an equivalent circuit diagram of a power supply circuit of the in-vehicle touch panel input device 1. FIG. FIG. 5 is a circuit diagram showing details of a signal processing circuit 13 and an integration processing circuit 14 in FIG. 4. It is a longitudinal cross-sectional view of the vehicle-mounted touch panel input device 1. 3 is an equivalent circuit diagram around the detection electrode 11 of the in-vehicle touch panel input device 1. FIG. It is explanatory drawing which shows the reception level Vi (capacity level) detected by each detection electrode 11 at the time of input operation from the driver's seat side. FIG. 10 is an explanatory diagram showing a reception level Vi (capacity level) detected by each detection electrode 11 when the same position as in FIG. 9 is input from the passenger seat side. It is a flowchart which shows the process from the detection of input operation to the output of an input operation position. It is a top view of the vehicle-mounted touch panel input device 50 which concerns on other embodiment of this invention. It is a top view of the vehicle-mounted touch panel input device 60 which concerns on other embodiment of this invention. It is a top view of the conventional car navigation apparatus 100 which detects an input operation direction.

  Hereinafter, a vehicle-mounted touch panel input device (hereinafter referred to as a touch panel) 1 according to a first embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 1 and 7, the touch panel 1 is formed on the insulating substrate 20 along the periphery of the rectangular frame-shaped insulating substrate 20 in which the horizontally-long rectangular opening 21 is formed in the center, and the periphery of the opening 21. .., And a transparent glass substrate 31 placed on the insulating substrate 20 with the detection electrode 11 sandwiched between the detection electrode 11 and the detection electrode 11 so as to cover the opening of the opening 21. A shield plate 32 that covers and is fixed to the insulating substrate 20 is provided.

  As shown in FIG. 2, the touch panel 1 according to the present embodiment is stacked and disposed above a liquid crystal display panel 40 that displays a map, a landmark, a guidance route, and the like as an input device of an in-vehicle car navigation device. Along with the laminated liquid crystal display panel 40, it is attached to the center console section (not shown) between the driver seat and the passenger seat in front of the vehicle. Therefore, a passenger in the driver's seat or the passenger seat (hereinafter referred to as an operator unless otherwise described about the passenger in one seat) sees the display on the liquid crystal display panel 40 through the transparent glass substrate 31 in the opening 21. However, the input operation can be performed by bringing the finger 30 close or in contact, and here, the surface of the glass substrate 31 surrounded by the opening 21 is defined as an input operation region E where the operator performs the input operation.

  As shown in FIG. 3, the directions along the rectangular outline are the X direction and the Y direction orthogonal to each other. Here, the passenger seat is on one side along the X direction on the left side of the figure, and the driver's seat is on the other side on the right side. Explain that there is a seat. Since the input operation direction from the passenger seat side and the driver seat side is discriminated and the input operation position on the input operation area E along the XY plane is detected by the xy position coordinates, one of the openings 21 opposed in the X direction is detected. A large number of detection electrodes X01, X02... X0n along the left side of the passenger side (passenger seat side), and a large number of detection electrodes X11, X12. A large number of detection electrodes Y01, Y02... Y0n along the lower side of one side (lower side in the figure) of the opening 21 facing each other, and a large number of detection electrodes Y11, Y12 along the upper side of the other side (upper side in the figure). ..Y1n is arranged. Each of the detection electrodes 11 (X0, X1, Y0, Y1) has the same size and is evenly arranged at a predetermined pitch in the X and Y directions (hereinafter referred to as arrangement direction) along each periphery of the opening 21. As a result, at any position in the input operation area E, the fingertip 30a of the finger 30 to be input is operated in at least one set of detection electrodes (X0n and X1n or Y0n and Y1n in each direction of the X direction and the Y direction). ).

  The insulating substrate 20 is a printed wiring board, and each detection electrode 11 (X0, X1, Y0, Y1) is connected to each of the multiplexers 12 described later by a strip-shaped lead wiring pattern 35 formed on the printed wiring board. Connected to the input terminal.

  As shown in FIG. 1, the shield plate 32 is fixed to the insulating substrate 20 so as to stand up outside the detection electrodes 11, and is bent horizontally toward the upper side of the opening 21. The bent inner end slightly protrudes toward the opening 21, thereby covering the entire vertical direction of each detection electrode 11. The shield plate 32 is connected to a low-voltage vibration power supply line SGND described later via a wiring pattern (not shown) on the insulating substrate 20 and is grounded on the vibration side circuit board 3. Accordingly, the shield plate 32 is interposed between each detection electrode 11 and a part of the wrist or arm of the operator excluding the finger 30 that performs the input operation, and will be described later between the finger 30 and each detection electrode 11. The influence of portions other than the finger 30 on the electrostatic capacitance Cm is reduced, and the input operation position of the finger 30 can be accurately detected from the electrostatic capacitance Cm. However, since there is no problem in detecting the input operation direction even if a portion other than the finger is affected, the shield plate 32 is not necessarily provided unless the input operation position is detected with high accuracy.

  As shown in FIG. 7, the glass substrate 31 placed on the insulating substrate 20 is disposed on the detection electrode 11 formed along the surface of the insulating substrate 20, and the input operation region E on the surface of the glass substrate 31. When the finger 30 approaches, a capacitance Cm is formed between the finger 30 and a capacitance Cma having a glass substrate 31 as a dielectric and a capacitance Cmb having air as a dielectric connected in series. The

  In the present embodiment, the reception level Vi of the AC detection signal appearing on each detection electrode 11 is set as a capacitance level representing the capacitance Cm between each detection electrode 11 and the finger 30, and the input operation direction, input operation, and The input operation position is detected, and the configuration of a circuit for detecting these will be described below.

  As shown in FIG. 4, the main circuit components constituting the touch panel 1 including the detection electrodes 11 are mounted on two types of non-vibration side circuit boards 2 and vibration side circuit boards 3. The non-vibration circuit board 2 is provided with a reference power supply circuit 4 including a low-voltage reference power supply line GND and a high-voltage reference power supply line VCC that are set to the ground potential, and a DC voltage Vcc between the low-voltage reference power supply line GND and the high-voltage reference power supply line VCC. Is connected to a DC power source 5. Thereby, each circuit component such as the interface circuit 6 mounted on the non-vibration circuit board 2 is connected to the reference power supply circuit 4 and driven by the output voltage Vcc of the DC power supply 5.

  Further, the vibration side circuit board 3 is provided with a vibration power circuit 7 including a low voltage vibration power line SGND and a high voltage vibration power line SVCC. The low-voltage vibration power supply line SGND is connected to the low-voltage reference power supply line GND, and the high-voltage vibration power supply line SVCC is connected to the high-voltage reference power supply line VCC via the coils 8 and 9, respectively. The inductances of the coil 8 and the coil 9 are both set to values having high impedance with respect to an AC detection signal SG having a natural frequency f described later. Here, the coils 8 and 9 having the same inductance L are used.

  An oscillation circuit 15 serving as a transmission means for transmitting the natural frequency f of the AC detection signal SG is mounted on the vibration side circuit board 3 and is branched into two branches via capacitors 17 and 18 having a capacitance C ′ that cuts off the DC voltage. The AC detection signal SG is connected to the low-voltage reference power line GND and the high-voltage reference power line VCC of the reference power circuit 4. As a result, when the AC detection signal SG having the natural frequency f is synchronized and output to the low voltage reference power line GND and the high voltage reference power line VCC of the reference power circuit 4, the low voltage reference power line GND of the reference power circuit 4 is grounded. Since the potential is stable, the potentials of the low-voltage vibration power supply line SGND and the high-voltage vibration power supply line SVCC of the vibration power supply circuit 7 fluctuate synchronously with the natural frequency f, and the voltage between them is the same DC output as that of the reference power supply circuit 4 The voltage is Vcc. The natural frequency f of the AC detection signal SG can be arbitrarily adjusted. Here, the AC detection signal SG having a natural oscillation frequency of 187 kHz is output.

  When the AC detection signal SG having the natural frequency f flows in the reference power supply circuit 4 and the vibration power supply circuit 7, the low-voltage reference power supply line GND and the high-voltage reference power supply line VCC and the low-voltage vibration power supply line SGND and the high-voltage vibration power supply line SVCC are close to each other. If the power supply lines are short-circuited in the band of the natural frequency f, the reference power supply circuit 4 and the vibration power supply circuit 7 are shown in the equivalent circuit diagram of FIG.

As shown in FIG. 5, since capacitors 17 and 18 having a capacitance C ′ are connected in parallel between the output of the oscillation circuit 15 on the vibration power supply circuit 7 side and the reference power supply circuit 4, the combined capacitance is 2C. In addition, the combined inductance of the coils 8 and 9 connected in parallel between the reference power supply circuit 4 and the vibration power supply circuit 7 is L / 2. These capacitors and inductors are connected in series in a closed circuit in which an AC detection signal SG having a natural frequency f flows, and the amplitude (level) of the AC detection signal SG is Vsg, the reference power supply circuit 4 at both ends of the coils 8 and 9 and the vibration power supply. If the voltage between the circuits 7 is Vs, and the angular velocity represented by 2πf is ω (rad / sec),
Vs = [ω ² LC ′ / (ω ² LC′−1)] Vsg (1)
Here, the circuit shown in FIG. 5 is in series resonance at ω ² LC ′ = 1, and the frequency f _{0 at} that time is
f ₀ = 1 / [2π (LC ′) ^1/2 ] (2)

That is, if the resonance frequency f ₀ obtained from the relationship of the expression (2) is the natural frequency f of the AC detection signal SG, the level of the AC detection signal SG is theoretically calculated from the expression (1) of the vibration power supply circuit 7. The potential vibrates at infinity, and the potential of each detection electrode 11 connected to the vibration power supply circuit 7 can be vibrated to infinity. The actual touch panel 1 does not resonate at the frequency f ₀ obtained from the equation (2) due to the influence of inductance, stray capacitance, etc. of the reference power supply circuit 4 and the vibration power supply circuit 7, and the reference power supply circuit 4 and the vibration power supply circuit 7. Due to the energy loss when the alternating current detection signal SG flows through, particularly the power consumption due to the internal resistance of the coils 8 and 9, the vibration power supply circuit 7 has an amplitude Vs that is expanded to a finite magnification with respect to the level Vsg of the alternating current detection signal SG. Vibrate.

  On the other hand, since a high voltage cannot be applied to each detection electrode 11 that the operator's finger 30 contacts through the glass substrate 31, a resistor (not shown) is connected between the output of the oscillation circuit 15 and the capacitors 17 and 18. Thus, the output level Vs of the AC detection signal SG in which each detection electrode 11 relatively vibrates is 5 V here.

  Also, the natural frequency f of the AC detection signal SG can be set to an arbitrary frequency, but is identified as a frequency used in other in-vehicle electronic devices and communication devices, and the AC detection signal having the natural frequency f. SG needs to be detected, and these used frequencies and their harmonics are avoided.

  Each of the detection electrodes 11 described above is connected to one of the low-voltage vibration power supply line SGND and the high-voltage vibration power supply line SVCC of the vibration power supply circuit 7, here the high-voltage vibration power supply line SVCC. All the detection electrodes 11 are connected to the high-voltage vibration power supply line SVCC, so that they vibrate at the natural frequency f at the output level Vs of the AC detection signal SG, while the operator's finger 30 is not in contact with the power supply circuits 4 and 7. Since the potential is a constant potential, a voltage of the output level Vs of the AC detection signal SG is generated between them, and when viewed from the vibration power supply circuit 7 that vibrates at the natural frequency f, the constant potential detection electrode 11, the finger 30 as an input operation body becomes a signal generation source that vibrates at the natural frequency f of the AC detection signal SG. Therefore, an AC detection signal SG having a natural frequency f appears on the detection electrode 11 where the finger 30 approaches and the capacitance Cm with the finger 30 increases.

  As shown in FIG. 7, the capacitance Cm between each detection electrode 11 and the finger 30 is as follows when the finger 30 is not touching the glass substrate 31. As described above, since the capacitance Cma using the glass substrate 31 connected in series as a dielectric and the capacitance Cmb using air as a dielectric, the capacitance Cm is Cma · Cmb / (Cma + Cmb). ). However, here, for ease of explanation, it is assumed that the finger 30 and the detection electrode 11 are separated by a uniform dielectric having a relative dielectric constant εr. Assuming that the distance between the detection electrode 11 and the finger 30 is d, the dielectric constant of vacuum is ε0, and the facing area between the finger 30 and the detection electrode 11 is s, the capacitance Cm between the detection electrode 11 and the finger 30 is Cm = ε0. Since it is expressed by εr · s / d and the natural frequency of the AC detection signal SG is f, the reactance Xc of the capacitance Cm with respect to the AC detection signal is Xc = 1 / (2π · f · Cm), Xc = d / (ω · ε0 · εr · s).

FIG. 8 is an equivalent circuit diagram of the entire signal detection circuit unit for detecting the reception level Vi of the AC detection signal SG appearing on the detection electrode 11, where Cp is a floating between the detection electrode 11 and the low-voltage vibration power supply line SGND. Capacitance, rp is the internal resistance value of the detection electrode 11, and R4 is the resistance value of the output resistance. In the equivalent circuit diagram in the figure,
i1 = i2 + i3 (3) Formula Vs = i1 / (jω · Cm) + i2 / (jω · Cp) (4) Formula −i2 / (jω · Cp) + i3 · rp + i3 · R4 = 0 -(5) Formula i3 * R4 = Vi ... The relationship of Formula (6) is established, and from Formula (3) to Formula (6),
Vi = [jω · Cm / {1 / R4 + jω (Cm + Cp) (rp / R4 + 1)}] · Vs (7) Equation (7) is obtained.

If the internal resistance rp is set to 0, and R4 is connected to an integration operational amplifier A / D25, which will be described later, via the multiplexer 12, so that it is infinite, the equation (7) becomes
Vi = Cm / (Cp + Cm) · Vs
Further, since the electrostatic capacitance Cm is very small compared to the stray capacitance Cp, the equation (7) is further expressed by the following equation: Vi = (Cm / Cp) · Vs (8).

  In the equation (8), since the stray capacitance Cp and the output level Vs of the AC detection signal SG for the detection electrode 11 are constant values, the reception level Vi of the AC detection signal SG appearing on the detection electrode 11 is the detection electrode 11. And a capacitance level representing the capacitance Cm between the finger 30 and the finger 30.

As described above, the capacitance Cm of the input operation body 30 and the detection electrode 11 is expressed by Cm = ε0 · εr · s / d. Therefore, if this is substituted into the equation (8) and transformed,
Vi = [ε0 · εr · s / (d · Cp)] · Vs (9) where (ε0 · εr · s / Cp) in equation (9) is a constant. If it is set to 1 / k, the reception level Vi of the AC detection signal SG appearing on the detection electrode 11 is:
Vi = Vs / (d · k) (represented by the equation (10)), the detection electrode 11 closer to the finger 30 is closer to the output level Vs of the AC detection signal SG. Become. However, if the finger 30 is close to the detection electrode 11 and the electrostatic capacitance Cm therebetween becomes so large that it cannot be ignored compared to the stray capacitance Cp, the equation (10) cannot be applied and the reception level Vi is the maximum. The output level becomes Vs.

Expression (10) indicates that the reception level Vi of the AC detection signal that appears on each detection electrode 11 that represents the capacitance Cm of each of the plurality of detection electrodes 11 and the finger 30 is inversely proportional to the distance d to the finger 30. The input operation position (x, y) is detected for the input operation in which the fingertip 30a contacts the glass substrate 31 so that the position of the finger base 30b is not erroneously detected as the input operation position (x, y). Then, the detection is made from the capacitance Cma between the detection electrode 11 and the fingertip 30a having only the glass substrate 31 whose dielectric constant is sufficiently higher than that of air as a dielectric. That is, the capacitance Cmb using air as a dielectric shown in FIG. 7 is sufficiently smaller than the capacitance Cma using the glass substrate 31 as a dielectric, so that the finger portion 30b not in contact with the glass substrate 31 is used. The capacitance Cmb between the detection electrode 11 and the detection electrode 11 can be ignored in the detection of the input operation position (x, y). In the figure, the relative ratio of the capacitances Cm ₀ and Cm _{1 that} the capacitance Cmb does not substantially affect. The input operation position (x) in the X direction is detected. Similarly, the distance between the finger 30 in contact with the input operation region E and each detection electrode 11 can be compared, and the arrangement position of each detection electrode 11 (X0, X1, Y0, Y1) and each detection electrode 11 can be compared. The input operation position (x, y) in the XY direction on the input operation area E is detected from (X0, X1, Y0, Y1) and the reception level Vi representing the capacity level of the finger 30.

  In order to detect the reception level Vi representing the capacitance level between each detection electrode 11 (X0, X1, Y0, Y1) and the finger 30, the vibration side circuit board 3 includes an analog multiplexer 12, a signal processing circuit 13, and an integration process. The circuit 14, the A / D converter 19, the MPU (microprocessor unit) 10, and the oscillation circuit 15 are mounted on the circuit elements, all of which are connected to the low-voltage vibration power line SGND and the high-voltage vibration power line SVCC of the vibration power circuit 7, It operates by receiving the output voltage Vcc from the DC power source 5.

  The analog multiplexer 12 switches and connects each detection electrode 11 to the signal processing circuit 13 at a constant period, here, every 200 msec by switching control from the MPU 10, and sequentially processes the AC detection signal SG appearing on each detection electrode 11. It is output to the circuit 13. That is, all the detection electrodes X01, X02..., X11, X12... Facing in the X direction and detection electrodes Y01, Y02. The detection electrode 11 is connected to the signal processing circuit 13.

  As shown in FIG. 6, the signal processing circuit 13 includes a resonance circuit 23 that passes a signal in a frequency band centered on the natural frequency f of the AC detection signal SG, an amplifier circuit 24 for impedance conversion, and a gap between them. The first analog switch ASW1 is connected in series. The resonance circuit 23 cuts low-frequency components such as a DC signal and high-frequency noise such as common mode noise from the signal appearing on the detection electrode 11 connected via the analog multiplexer 12, and only the AC detection signal SG is used in the subsequent amplification circuit. To 24. The amplifier circuit 24 is an impedance conversion element having an input impedance close to infinity and an output impedance of a minute value. Even if the weak AC detection signal SG appears on the detection electrode 11, an integration process connected to the output side of the amplification circuit 24. The circuit 14 is made to operate.

  The first analog switch ASW1 is controlled to be opened and closed by the MPU 10, and connects the resonance circuit 23 and the amplifier circuit 24 during an integration operation period (Tint) in which the integration processing circuit 14 performs an integration operation described later, thereby adjusting an offset described later. Cut off during period (Tset). This prevents the AC detection signal SG from being output to the integration processing circuit 14 during the offset adjustment period (Tset).

  The integration processing circuit 14 includes a clamp diode circuit 28 having its anode and cathode connected to each other, a pull-up resistor 29 that raises the output potential of the signal processing circuit 13 to a predetermined potential, an operational amplifier 25 for integration, and a signal processing circuit. 13 and the integrating resistor R1 connected between the inverting input terminal of the integrating operational amplifier 25, the integrating capacitor C1 connected between the inverting input terminal and the output terminal of the integrating operational amplifier 25, and the integrating capacitor C1. A second analog switch ASW2 connected in parallel and controlled to be opened and closed by the MPU 10 is provided.

  The clamp diode circuit 28 clamps the output of the signal processing circuit 13, that is, the voltage of the AC detection signal SG so as to oscillate within the range of the forward voltage of the pair of diodes around the potential pulled up by the pull-up resistor 29. And output to the integrating resistor R1.

The voltage of the AC detection signal input to the inverting input terminal of the integrating operational amplifier 25 via the integrating resistor R1 is Vin, the voltage output from the output terminal of the integrating operational amplifier 25 is Vout, and the resistance value of the integrating resistor R1 is R, if the capacitance of the integrating capacitor C1 is C,
Vout = −1 / CR · ∫Vindt (11) The voltage Vout obtained by integrating the input voltage Vin is output from the output terminal of the integrating operational amplifier 25.

  The second analog switch ASW2 is controlled to be closed by the MPU 10 for a short time after the start of the offset adjustment period (Tset), so that the charge accumulated in the integrating capacitor C1 can be quickly transferred during the integration operation period (Tint) of the integration processing circuit 14. The charging voltage that is discharged and charged in the integrating capacitor C during the immediately preceding integration operation period (Tint) does not affect the offset operation during the offset adjustment period (Tset) of the integration processing circuit 14 described later.

There is a DC component error between the inverting input terminal and the non-inverting input terminal of the integrating operational amplifier 25 due to the offset voltage of the integrating operational amplifier 25 and other factors, and the combined error voltage is represented by the offset voltage Δv. , (11)
Vout = −1 / CR · ∫ (Vin + Δv) dt (12) Since the offset voltage Δv is a direct current component, the expression (12) is
Vout = −1 / CR · ∫Vindt−Δv · t / CR (13) As the time t elapses, the error due to the offset voltage Δv in the output voltage Vout increases.

  Therefore, a feedback circuit unit is further provided in the integration processing circuit 14 for the purpose of substantially eliminating the influence of the offset voltage Δv. As shown in FIG. 6, this feedback circuit section includes a feedback operational amplifier 26, a third analog switch ASW3 connected between the output of the feedback operational amplifier 26 and the non-inverting input terminal of the integrating operational amplifier 25, and a third analog switch. The hold capacitor 27 is connected between the switch ASW3 and the non-inverting input terminal of the integrating operational amplifier 25 and charged with the output voltage of the feedback operational amplifier 26.

  The non-inverting input terminal of the feedback operational amplifier 26 is connected to the output of the integrating operational amplifier 25 via the resistor R2, and the inverting input terminal is connected to the input side of the integrating resistor R1. The resistance values of the resistor R3 and the resistor R2 connected between the inverting input terminal and the output terminal of the feedback operational amplifier 26 are equal. Therefore, the feedback operational amplifier 26 is used for integration while the third analog switch ASW3 is closed and controlled. Using the input voltage Vin input to the inverting input terminal of the operational amplifier 25 as a reference potential, the difference between the output voltage Vout of the integrating operational amplifier 25 and the input voltage Vin is amplified by gain −1 and fed back to the non-inverting input terminal of the integrating operational amplifier 25. Acts like

  During the offset adjustment period (Tset) controlled by the MPU 10, the third analog switch ASW3 is closed and controlled, and the input of the integrating resistor R1 and each detection electrode 11 are shut off by the first analog switch ASW1 controlled to open. Therefore, the AC detection signal SG is not input to the input side of the integrating resistor R1, and the potential of the inverting input terminal of the integrating operational amplifier 25 is maintained at a constant input voltage Vin.

  Assuming that the offset voltage Δv is generated at the inverting input terminal with respect to the non-inverting input terminal of the integrating operational amplifier 25, the integrated value − (Vin + Δv) · Δt / CR is output after Δt. 26, Vin + (Vin + Δv) · Δt / CR is input to the non-inverting input terminal of the integrating operational amplifier 25, and Δt / CR is sufficiently smaller than 1. By repeating this, the output of the integrating operational amplifier 25 is offset. It converges to the voltage Δv and stabilizes. In this state, the potential obtained by adding the offset voltage Δv to the inverting input terminal of the integrating operational amplifier 25 becomes equal to the potential of the non-inverting input terminal, and the non-inverting input including the influence of the offset voltage Δv is applied to the holding capacitor 27. A correction voltage is charged so that the voltage difference between the terminal and the inverting input terminal is zero. Therefore, the offset adjustment period (Tset) is set to a sufficient time for the output Vout of the integrating operational amplifier 25 to reach the offset voltage Δv and stabilize, and the hold capacitor 27 is used when the output Vout of the integrating operational amplifier 25 is stabilized. For this, a capacitor of a saturated capacitor is used.

  After the elapse of the offset adjustment period (Tset), the MPU 10 controls to close the first analog switch ASW1, and controls to open the third analog switch ASW3, and shifts to the integration operation period (Tint). In the integration operation period (Tint), the first analog switch ASW1 is closed and controlled, so that the AC detection signal SG appearing on the detection electrode 11 selectively connected by the analog multiplexer 12 is input to the inverting input terminal of the integration operational amplifier 25. . Further, since the third analog switch ASW3 is controlled to open, the correction voltage charged in the hold capacitor 27 is input to the non-inverting input terminal of the integrating operational amplifier 25 during the offset adjustment period (Tset), and the offset voltage The difference voltage between the non-inverting input terminal and the inverting input terminal of the integrating operational amplifier 25 including Δv becomes 0, and an error −Δv · t obtained by integrating the offset voltage Δv shown in the equation (13) into the output Vout of the integrating operational amplifier 25. / CR is not included.

  As a result, only the voltage Vin of the minute AC detection signal SG is integrated and expanded, and appears as the output Vout of the integrating operational amplifier 25. The MPU 10 starts after the integration operation period (Tint) and after the same time has elapsed in each integration operation period (Tint) and immediately before the end of the integration operation period (Tint), at the determination time t1. The output Vout is output to the A / D converter 19 connected to the subsequent stage. The integration operation period (Tint) is sufficiently shorter than the saturation time of the integration capacitor C1 determined by CR, and the voltage Vin of the AC detection signal SG is obtained from the output Vout of the integration operational amplifier 25, which is the integration value at the determination time t1. Set to a distinguishable period.

  The A / D converter 19 quantizes the output Vout of the integrating operational amplifier 25 at the determination time t1 and outputs it to the MPU 10. The quantized data output from the A / D converter 19 represents the reception level Vi of the AC detection signal SG appearing at each detection electrode 11 selectively connected by the analog multiplexer 12 during the integration operation period (Tint). As described above, the integration processing circuit 14 expands only the minute voltage voltage Vin without increasing the error to obtain the output Vout. Therefore, the integration processing circuit 14 is about several pF from fF between the detection electrode 11 and the finger 30 that separates the air. The capacitance level of the extremely small capacitance Cm (Cmb) is also expressed by the quantized data (reception level Vi) output from the A / D converter 19 and is separated from the surface of the glass substrate 31 (input operation area E). The distance between the finger portion 30b and each detection electrode 11 can also be detected from the reception level Vi.

  The MPU 10 to which the quantized data representing the reception level Vi is input also functions as an input operation detection unit, a direction determination unit, and an input position detection unit. Based on the reception level Vi detected for each detection electrode 11, the input operation region An input operation for approaching the finger 30 to E, an input operation direction, and an input operation position (x, y) where the fingertip 30a is brought into contact with the input operation area E are detected. The MPU 10 is further connected to the interface circuit 6 mounted on the non-vibration circuit board 2 via the signal line 16 in which the direct current is insulated, and the input operation position (x, y) detected from the interface circuit 6 to the car navigation device. ), And sensor signals from a vehicle running sensor and a seating sensor (not shown) are inputted from the interface circuit 6.

  The vehicle travel sensor outputs a travel signal to the MPU 10 while the vehicle equipped with the touch panel 1 is traveling, specifically while the shift lever operated by the driver is in the drive “D” position. The seating sensor outputs a seating signal to the MPU 10 while an occupant is seated in the passenger seat, specifically, while a certain vertical load is applied to the passenger seat.

  Hereinafter, the above-described operation by the MPU 10 when there is an input operation on the touch panel 1 will be described in detail along the flow shown in FIG.

The MPU 10 monitors quantized data (simply referred to as a reception level Vi in the following processing) that is periodically input for all the detection electrodes 11, and the reception level Vi of any one of the detection electrodes 11 is a predetermined input threshold Viref. It is determined that there is an input operation when the value exceeds the threshold value, and it is determined that the input operation is being performed while the input threshold value Viref is exceeded (S1). The input threshold Viref can be set to an arbitrary value as long as an input operation for bringing the finger 30 closer to the input operation area E can be detected, but here, as shown in FIG. when brought close, it is set to the reception level Vi appearing on the detection electrode 11 ₁ closest to the fingertip 30a.

  When the reception level Vi of any of the detection electrodes 11 is less than the predetermined input threshold value Viref, it is determined that erroneous detection or input operation has been canceled, and the reception level Vi for each detection electrode 11 is again set as the input threshold value. Return to the standby state to compare with Viref.

  When an input operation is detected, the output of the vehicle travel sensor input via the interface circuit 6 is determined (S2). If a travel signal indicating that the vehicle is traveling is not input, the vehicle is stopped. The process proceeds to step S5 where the input operation position (x, y) is detected and output. On the other hand, if a travel signal is input, the output of the seating sensor is determined to determine whether or not the detected input operation is to be valid (S3).

  If no seating signal is input from the seating sensor, the input operation detected in step 1 is determined to be an unauthorized operation by the driver when no passenger is seated in the passenger seat, and the input operation is ignored. , MPU 10 returns to the standby state. On the other hand, when the seating signal is input, the input operation direction is further determined as to whether the input operation is from the driver seat side or the passenger seat side (S4).

  Before detecting the input operation position (x, y), the MPU 10 monitors the reception level Vi appearing on the detection electrode 11 (Y0 or Y1) arranged along the X direction that is periodically input. The input operation direction is determined from the moving direction of the arrangement position of the detection electrode 11 (Y0 or Y1) where the level Vi increases.

  For example, as shown in FIG. 9, when an input operation is performed from the driver's seat side, the detection electrode 11 (Y1) approaches the finger 30 in the order of detection electrodes Y1k + 2, Y1k + 1, Y1k arranged from right to left. As a result, the capacitance Cm with the finger 30 increases, and the reception level Vi increases in the order of the detection electrodes Y1k + 2, Y1k + 1, and Y1k. On the contrary, when an input operation is performed from the passenger side, the detection electrode (Y1) approaches the finger 30 as the finger 30 approaches in the order of Y1k, Y1k + 1, Y1k + 2 of the detection electrode 11 arranged from left to right. The capacitance Cm increases, and the reception level Vi appearing on the detection electrode (Y1) increases in the order of Y1k, Y1k + 1, and Y1k + 2 arranged on the side arranged from the left to the right. Therefore, the MPU 10 monitors the reception level Vi appearing on each detection electrode 11 of the detection electrode 11 (Y0 or Y1), and the arrangement position of the detection electrode 11 (Y0 or Y1) where the reception level Vi increases moves to the left side. If it is, it is determined that the operation is unauthorized by the driver, the input operation is ignored, and the MPU 10 returns to the standby state. On the other hand, if it is moving to the right in the reverse direction, it is determined that the input operation is from the passenger seat side, and the process proceeds to step S5 where the input operation position (x, y) is detected and output.

  In step S5, the MPU 10 detects and outputs the input operation position (x, y). As described above, the input operation position (x, y) is detected by detecting the detection electrode 11 in which the peak of the reception level Vi appears for each detection electrode 11 (X0, X1, Y0, Y1) in the X and Y arrangement directions. Although it may be detected from the arrangement position, here, the total sum SVx0, SVx1, SVy0, SVy1 of the reception level Vi appearing on the detection electrode 11 (X0, X1, Y0, Y1) for each arrangement direction is calculated, and from this sum The input operation position of the finger 30 in the XY directions is detected.

Assuming that the finger 30 touches the glass substrate 31 at the position shown in FIG. 7 and is at the input operation position P (x), the distance between the pair of detection electrodes X0 and X1 facing each other in the X direction is Lx, and arbitrary detection is performed. The reception level Vi0 of the AC detection signal SG appearing on the electrode X0n and the reception level Vi1 of the AC detection signal SG appearing on the detection electrode X1n arranged at a position facing the detection electrode X0n in the X direction are respectively expressed by the equation (10). ,
Vi0 = Vs / (x · k) (14) Formula Vi1 = Vs / ((Lx−x) · k) (15) The ratio Vi0 / Vi1 of both is
Vi0 / Vi1 = (Lx−x) / x (16)

Since this relationship holds for all pairs of detection electrodes X0 and X1 that face each other in the X direction, the sum of the reception levels Vi of the AC detection signals SG appearing on each detection electrode X0 within one scanning period is SVx0. If the sum of the reception levels Vi of the AC detection signal SG appearing in X1 is SVx1,
SVx0 / SVx1 = (Lx−x) / x (17). If x is solved,
x = Lx · SVx1 / (SVx0 + SVx1) (18)

Similarly, in the Y direction, if the distance between a pair of detection electrodes Y0 and Y1 facing in the Y direction is Ly, the reception level Vi0 of the AC detection signal SG appearing on any detection electrode Y0n and the detection electrode Y0n The relationship with the reception level Vi1 of the AC detection signal SG appearing at the detection electrode Y1n arranged at a position facing the Y direction is as follows:
Vi0 / Vi1 = (Ly−y) / y (19) The sum of the reception levels Vi of the AC detection signals SG appearing on each detection electrode Y0 within one scanning cycle is SVy0, and each detection electrode Y1. The sum of the reception levels Vi of the AC detection signal SG appearing in
y = Ly · SVy1 / (SVy0 + SVy1) (20) Since the relationship of the equation (20) is obtained, the input operation position (x, y) in the XY direction on the input operation area E can be easily obtained from SVx0, SVx1, SVy0, SVy1. Is obtained.

  The input operation position (x, y) detected by the MPU 10 is output to the car navigation device via the interface circuit 6 connected by the signal line 16, and the input to the input operation position (x, y) in the car navigation device. A predetermined process corresponding to the operation is executed.

  In the above-described embodiment, it is effective only when the input operation direction is determined at the stage where the input operation before detecting the input operation position (x, y) is detected and the input operation is from the passenger seat side. When the input operation position (x, y) is output as an input operation, but after the input operation position (x, y) is detected, the input operation direction is detected and it is determined that the input operation is from the passenger seat side. Only the detected input operation position (x, y) may be output.

  When the input operation direction is determined after detecting the input operation position (x, y), it can be estimated that the operator's fingertip 30a is close to the detected input operation position (x, y). The detection electrode 11 arranged symmetrically with respect to the input operation position (x, y) indicates whether the finger portion 30b such as the base of the finger 30 or the palm is on the driver seat side or the passenger seat side with respect to 30a. The reception level Vi is compared and determined. That is, a capacitance Cm is also formed between each detection electrode 11 and the finger base portion 30b such as the base of the finger 30 or the palm. The capacitance Cm formed between the finger portion 30b and the finger portion 30b is an electrostatic capacitance Cmb mainly using air as a dielectric because the finger portion 30b is spaced upward from the input operation area E. Since it is extremely small compared to the capacitance Cm with the fingertip 30a close to the operation area E, it can be ignored in detecting the input operation position (x, y). However, since an increase in the reception level Vi appearing on the detection electrode 11 can be detected by the electrostatic capacitance Cm between the finger portion 30b and the input operation position (x) in the X direction (the driver seat side and the passenger seat side). The reception level Vi appearing on the detection electrodes 11 arranged at substantially equal distances in the direction of connection) is compared, and the input operation position of the detection electrode 11 where the distance to the fingertip portion 30b is closer and a higher reception level Vi is detected. The input operation direction can be determined from the arrangement direction from (x, y).

  For example, in the touch panel 1 described above, as shown in FIGS. 9 and 10, from the detection electrodes 11 (Y0) arranged along the X direction, three pieces arranged on the driver side at the input operation position (x). Detection electrodes (Y0b, Y0b + 1, Y0b + 2) are selected as the first detection electrode group (Yb), and the same number of first detection electrode groups (Yb) as the first detection electrode group (Yb) and the input operation position (x ), Three detection electrodes (Y0a, Y0a + 1, Y0a + 2) arranged on the passenger seat side which are substantially symmetrical positions are selected as the second detection electrode group (Ya), and reception appears in the first detection electrode group (Yb). The total sum SVyb of the level Vi is compared with the total sum SVya of the reception level Vi appearing in the second detection electrode group (Ya).

  As shown in FIG. 9, when there is an input operation from the driver's seat side, there is a finger base 30b such as the base of the finger 30 or the palm on the driver's seat side from the input operation position (x). The total SVyb of the detection electrode group (Yb) is larger than the total SVya of the second detection electrode group (Ya), and can be determined as an input operation from the driver side.

  On the other hand, even if the input operation position (x, y) is at the same position as in FIG. 9, in the input operation from the passenger seat side, as shown in FIG. 10, the fingertip portion 30b of the operator's finger 30 is moved to the fingertip 30a. The total SVya of the second detection electrode group (Ya) that is present on the left side of the input operation position (x) and closer to the finger portion 30b is larger than the total SVyb of the first detection electrode group (Yb). The MPU 10 can be determined as an input operation from the passenger seat side.

  In the above-described embodiment, the surface of the glass substrate 31 is used as the input operation region E. However, even if the glass substrate 31 is not necessarily arranged, detection of the input operation and the input operation position (x, y) and the input operation direction are performed. Can be discriminated

  In addition, a large number of detection electrodes are not limited to the case where they are arranged around the input operation area E, but are insulated with the surface as the input operation area E as in the touch panel 50 according to the second embodiment shown in FIG. A large number of detection electrodes 52 may be arranged on the substrate 51 in a matrix while being insulated from each other. This touch panel 50 has the same configuration as that of the touch panel 1 except for the number and arrangement positions of the detection electrodes 52, and each detection electrode 52 formed so as to have substantially the same area along the input operation region E has a multiplexer. By connecting to each of the 12 input terminals, the reception level Vi appearing on each detection electrode 52 is periodically detected.

  As a result, since the reception level Vi appearing on any one of the detection electrodes 52 exceeds the predetermined input threshold Viref, an input operation for bringing the finger 30 closer to the input operation area E is detected, and the reception level Vi appearing on each detection electrode 52 is set. Monitoring is performed, and the position of the detection electrode 52 where the reception level Vi increases can be determined as an input operation from the passenger seat side by moving from the passenger seat side to the driver seat side. Further, the input operation position (x, y) is determined from the arrangement position in the XY direction of the detection electrode 52 that has detected the largest reception level Vi, or the relative ratio of the reception levels Vi of the plurality of detection electrodes 52 and the detection electrode 52. It can detect from the relationship with the arrangement position of XY direction. After detecting the input operation position (x, y), a detection electrode group consisting of one or more detection electrodes 52 arranged equidistantly on the right and left sides in the X direction around the input operation position (x). The input operation direction can be determined by comparing the sum of the reception levels Vi that appear.

  Further, the large number of detection electrodes are not limited to a flat plate shape, and may be formed in an elongated band shape along the input operation region E. FIG. 13 shows a third embodiment in which a large number of detection electrodes are composed of a plurality of X detection electrodes 61X wired along the Y direction and a plurality of Y detection electrodes 61Y wired along the X direction. 1 shows a touch panel 60 according to an embodiment, and a plurality of X detection electrodes 61X are wired at an equal pitch in the X direction on an upper insulating substrate 62 whose surface is an input operation region E, and the Y detection electrodes 61Y are upper insulating substrates 62. Are wired at the same pitch in the Y direction on the lower insulating substrate 63 stacked below the substrate. The touch panel 60 also has the same configuration as that of the touch panel 1 except for the configuration related to the insulating substrates 62 and 63 and the detection electrodes 61X and 61Y. The detection electrodes 61X and 61Y are connected to the input terminals of the multiplexer 12, respectively. As a result, the reception level Vi appearing on each of the detection electrodes 61X and 61Y is periodically detected.

  As a result, the reception level Vi appearing on any one of the detection electrodes 61X and 61Y exceeds the predetermined input threshold Viref, and therefore an input operation for bringing the finger 30 closer to the input operation area E is detected, and the reception level appearing on each detection electrode 61X. By monitoring Vi and the arrangement position of the detection electrode 61X at which the reception level Vi increases moves from the passenger seat side to the driver seat side, it can be determined that the input operation is from the passenger seat side. The input operation position (x, y) is determined from the arrangement position of the detection electrodes 61X and 61Y that detected the maximum reception level Vi, or the relative ratio of the reception levels Vi of the plurality of detection electrodes 61X and 61Y and the detection electrodes. 52 can be detected from the relationship with the arrangement position of 52 in the XY direction. After detecting the input operation position (x, y), the detection electrode group including one or more detection electrodes 61X arranged at equal distances on the right and left sides in the X direction with the input operation position (x) as the center. The input operation direction can be determined by comparing the sum of the reception levels Vi that appear. Note that the Y detection electrode 61 </ b> Y may be formed along the back surface of the upper insulating substrate 62.

  In each of the embodiments described above, the detection electrode is vibrated at the output level Vs of the AC detection signal SG with respect to the input operator's finger 30, and a relative potential of the output level Vs is generated between them. The potential of the input operator's finger 30 may be varied with the output level Vs of the AC detection signal SG with the side as a constant potential.

  Further, although the right side in the X direction is described as the driver's seat side and the left side as the passenger seat side, when the driver's seat is on the left side toward the front of the vehicle, the input operation direction from the passenger seat side on the right side in the X direction Is a valid input operation.

  Further, since the capacitance level detected for each of the detection electrodes arranged in the input operation region E or the periphery thereof is proportional to the surface area along the input operation region E of the detection electrode, the capacitance level is assumed to be equal for each detection electrode. Is preferably inversely proportional to the distance from the operator's finger 30. However, the shape and size of the detection electrode formed along the input operation area E is arbitrary, and when the surface area is varied at a known ratio, the detected capacitance level is divided by the ratio of the surface area. Thus, the distance from the operator's finger may be compared.

  INDUSTRIAL APPLICABILITY The present invention is suitable for a vehicle-mounted touch panel input device that can perform an input operation of a vehicle-mounted electronic device from either the driver seat side or the passenger seat side and prohibits the driver's input operation while the vehicle is traveling.

1 In-vehicle touch panel input device (first embodiment)
10 MPU (input operation detection means, input position detection means, direction discrimination means)
11 Detection electrode 40 Display panel 50 Touch panel input device for in-vehicle use (second embodiment)
52 Detection electrode 60 In-vehicle touch panel input device (third embodiment)
61X, 61Y Detection electrode E Input operation area Vi AC detection signal reception level (capacity level)
Viref input threshold

Claims (7)

In order to operate the in-vehicle electronic device, in front of the driver's seat and the passenger seat in the vehicle, it is attached over the display panel that guides and displays the operation to the in-vehicle electronic device,
A plurality of detection electrodes arranged in a distributed manner in the vicinity of the input operation area set to overlap the display panel;
Capacitance detection means for detecting a capacitance level representing the capacitance between the detection electrode and the input operator's finger for each detection electrode;
An input operation detection means for detecting an input operation to the input operation area because the capacitance level of any one or more detection electrodes detected by the capacitance detection means exceeds a predetermined input threshold;
Direction discriminating means for discriminating whether an input operation has been performed on the input operation area from either the driver seat or the passenger seat in the vehicle;
An in-vehicle touch panel input device that enables only an input operation that the direction determination unit determines to be an input operation from the passenger seat side when the input operation detection unit detects an input operation while the vehicle is traveling. ,
The direction discriminating unit monitors the capacitance level detected for each detection electrode while the input operation detection unit is detecting the input operation, and the arrangement position of the detection electrode where the increase in the capacitance level is detected is the passenger seat side. An in-vehicle touch panel input device, wherein the input operation is discriminated as an input operation from the passenger seat side when the vehicle is moving from the driver seat side to the driver seat side. An input position detecting means for detecting an input operation position to the input operation area from a capacitance level detected by the electrostatic capacity detection means for any one or two or more detection electrodes and an arrangement position of the detection electrodes;
2. The in-vehicle touch panel input device according to claim 1, wherein the input operation position detected by the input position detection unit is output only for the input operation determined by the direction determination unit as an input operation from the passenger seat side. It further comprises a seating sensor that detects the seating of the passenger in the passenger seat,
The direction determination means determines that the input operation is from the passenger seat side only when the seating sensor detects the seating of a passenger in the passenger seat. The in-vehicle touch panel input device according to claim 1. In order to operate the in-vehicle electronic device, in front of the driver's seat and the passenger seat in the vehicle, it is attached over the display panel that guides and displays the operation to the in-vehicle electronic device,
A plurality of detection electrodes arranged in a distributed manner in the vicinity of the input operation area set to overlap the display panel;
Capacitance detection means for detecting a capacitance level representing the capacitance between the detection electrode and the input operator's finger for each detection electrode;
Input operation detection means for detecting an input operation to the input operation area from a capacitance level detected by the capacitance detection means for any one or two or more detection electrodes;
Input position detection means for detecting an input operation position to the input operation area from a capacitance level detected by the capacitance detection means for any one or two or more detection electrodes and an arrangement position of the detection electrodes;
Direction discriminating means for discriminating whether an input operation has been performed on the input operation area from either the driver seat or the passenger seat in the vehicle;
When the input operation detecting means detects an input operation while the vehicle is running, the input operation position detected by the input position detecting means is only the input operation determined by the direction determining means to be an input operation from the passenger seat side. An in-vehicle touch panel input device that outputs
The direction discriminating means has one or two or more detection electrodes arranged on the driver seat side at the symmetric position at the input operation position detected by the input position detecting means with the same surface area along the input operation area. A first detection electrode group and a second detection electrode group consisting of one or more detection electrodes arranged on the passenger seat side are selected, and the capacitance level detected by the capacitance detection means for the first detection electrode group is selected. An in-vehicle touch panel input device, wherein the input operation from the passenger seat side is determined when the second sum of the capacitance levels detected by the capacitance detection means for the second detection electrode group is larger than the one sum. A transmission means for transmitting an AC detection signal in which the relative potential between each detection electrode and the input operator's finger varies;
The capacitance detection means detects the reception level of the AC detection signal appearing on each detection electrode as a capacitance level via the capacitance between each detection electrode and the input operator's finger,
The input position detection means compares the relative distance between the input operator's finger and the position of the detection electrode based on the capacitance level detected for any two or more detection electrodes, and enters the input operation area. The in-vehicle touch panel input device according to claim 4, wherein the input operation position is detected. It further comprises a seating sensor that detects the seating of the passenger in the passenger seat,
The direction determination means determines that the input operation is from the passenger seat side only when the seating sensor detects the seating of a passenger in the passenger seat. The in-vehicle touch panel input device according to claim 1. The in-vehicle touch panel input device according to any one of claims 1 to 6, wherein the in-vehicle electronic device is a car navigation device.

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