JP5533738B2 - Ultrasonic detector - Google Patents

Description

  The present invention relates to an ultrasonic detection apparatus.

  2. Description of the Related Art Conventionally, there is known an ultrasonic detection device that detects the presence or absence of an object and the distance from the object by transmitting an ultrasonic wave and receiving a reflected wave reflected from the object (for example, an obstacle).

  As an example of such an ultrasonic detection apparatus, there is an ultrasonic transmitter driving apparatus disclosed in Patent Document 1. This drive device for an ultrasonic transmitter generates an ultrasonic wave by supplying a drive signal composed of a voltage signal to a vibrator. For example, a control unit that controls a voltage signal supplied to the vibrator is provided, and the control unit oscillates a control signal having a phase opposite to that of the drive signal immediately after the drive signal whose voltage changes periodically is supplied to the vibrator. This is supplied to the child to suppress the reverberation of the vibrator.

JP 2007-85867 A

  As described above, in the driving device of the ultrasonic transmitter, immediately after supplying the driving signal to the vibrator in order to generate the ultrasonic wave, the control signal having the opposite phase to the driving signal is supplied to the vibrator. Yes. However, immediately after the drive signal is supplied to the vibrator, the reverberation energy is large. Therefore, immediately after supplying a drive signal to the vibrator (that is, without a delay time), if a control signal having a phase opposite to that of the drive signal is supplied to the vibrator, it is necessary to supply a control signal with a large voltage. Is bad.

  The vibrator is generally represented by an equivalent circuit including a parallel circuit of a series resonant circuit including an equivalent series inductor, an equivalent series capacitor, and an equivalent series resistance, and an equivalent parallel capacitor. Further, a capacitor connected in parallel with a vibrator (equivalent parallel capacitor), a transformer, or the like may be used for the drive circuit (driver circuit). The element constants of these elements are selected so as to minimize the reverberation time according to the characteristics of the vibrator to be used.

  By the way, in the ultrasonic detection apparatus, when transmitting ultrasonic waves, inductive energy is stored in the equivalent series inductor and the transformer of the drive circuit, and electrostatic energy is stored in the equivalent series capacitor, the equivalent parallel capacitor, and the capacitor of the drive circuit. These induced energy and electrostatic energy are damped by an equivalent series resistance after transmission is completed. The reverberation in the ultrasonic detection device is caused by the vibrational attenuation of this inductive energy and electrostatic energy by the equivalent series resistance. Therefore, the reverberation time in the ultrasonic detection device varies depending on element constants in the vibrator and the drive circuit.

  Therefore, the driving device of the ultrasonic transmitter can suppress reverberation when the element constants in the vibrator and the driving circuit have a specific value, but suppress reverberation when the element constant is different from the specific value. May not be possible. In other words, the drive device of the ultrasonic transmitter can suppress reverberation in the case of a combination of a specific vibrator and a drive circuit, but may not be able to suppress reverberation if the combination is different. As described above, the drive device of the ultrasonic transmitter may not be able to suppress reverberation when the element constants of the vibrator and the drive circuit vary.

  The present invention has been made in view of the above problems, and provides an ultrasonic detection device capable of shortening the reverberation time even when the element constants of the vibrator and the drive circuit vary. Objective.

In order to achieve the above object, an ultrasonic detection apparatus according to claim 1 is provided.
An ultrasonic detection device that performs a detection operation of detecting an object by transmitting an ultrasonic wave and receiving a reflected wave reflected from the object,
A transducer that transmits ultrasonic waves;
A drive circuit for driving the vibrator;
Controls driving of the vibrator by the driving circuit, and applies driving means for applying a transmission pulse for transmitting ultrasonic waves for detection from the vibrator to the driving circuit, and for suppressing reverberation of the vibrator. A control circuit including damping means for applying a damping pulse to the drive circuit after a predetermined time delay from the application of the transmission pulse;
The pulse width of the damping pulse and the application of the transmission pulse as the timing of applying the damping pulse are set so that the reverberation time becomes a predetermined value based on the element constant inherent to the vibrator and driving circuit measured in advance. A first storage unit that stores a damping pulse condition including a delay time from the end point,
The damping means applies the damping pulse to the drive circuit based on the damping pulse condition (pulse width and delay time) stored in the first storage unit.

  As described above, since the vibration suppression pulse is applied to the drive circuit based on the vibration suppression pulse condition set based on the element constant inherent to the vibrator and the drive circuit measured in advance, Even when the element constants vary, the reverberation time can be shortened. In other words, the reverberation time is shortened even when the element constants of the vibrator and drive circuit are different from a specific value, or when the combination of the vibrator and drive circuit is different from the combination of the specific vibrator and drive circuit. Can do. Further, the reverberation energy is smaller when the transmission pulse is delayed for a predetermined time than immediately after the transmission pulse is applied. Therefore, by applying a damping pulse with a predetermined time delay after the transmission pulse is applied in this way, the reverberation time can be reduced with a damping pulse having a smaller voltage than when the damping pulse is applied immediately after the transmission pulse is applied. It is efficient because it can be shortened.

  In addition, element constants of the vibrator and the drive circuit vary depending on the temperature. Therefore, when the ambient temperature of the ultrasonic detection device changes, the reverberation time also changes.

Therefore, as shown in claim 2,
Temperature information acquisition means for acquiring temperature information indicating the ambient temperature;
A second storage unit storing element constants inherent to the vibrator and the drive circuit measured in advance;
A plurality of combinations of ambient temperature, element constant, delay time, and pulse width, and a third storage unit that stores a plurality of reverberation times measured in advance in each combination,
The control circuit includes a selection unit that selects a damping pulse condition that provides a predetermined reverberation time from the third storage unit according to the element constant stored in the second storage unit and the temperature information acquired by the temperature information acquisition unit. Including
If the damping pulse condition selected by the selection means is different from the damping pulse condition stored in the first storage unit, the damping means changes to the damping pulse condition selected by the selection means. A vibration pulse may be applied to the drive circuit.

  In this way, even when the ambient temperature of the ultrasonic detection apparatus changes, it is possible to select a damping pulse condition that provides a predetermined reverberation time at that temperature. That is, it is possible to select a damping pulse condition that can shorten the reverberation time according to the ambient temperature. Since the vibration suppression pulse is applied to the drive circuit based on the vibration suppression pulse condition, it is possible to suppress an increase in the reverberation time even when the ambient temperature of the ultrasonic detection device changes. That is, it is possible to suppress an increase in reverberation time regardless of the ambient temperature.

  The plurality of reverberation times stored in the third storage unit are previously measured by a plurality of combinations of the ambient temperature of the vibrator, the element constant, the delay time, and the pulse width. Therefore, the accuracy of the reverberation time depends on the number of combinations that are measured.

  Accordingly, the reverberation time stored in the third storage unit in association with the vibration suppression pulse condition selected by the selection means, and the actual reverberation generated when the vibration suppression pulse is applied using the vibration suppression pulse condition. It may be different from time.

Therefore, as shown in claim 3,
With reverberation measuring means to measure the reverberation time of the vibrator,
The control circuit
Each damping pulse condition associated with a reverberation time within a predetermined time range is extracted from the third storage unit, and a transmission pulse and a damping pulse based on each damping pulse condition are extracted for each extracted damping pulse condition. Trial hitting means for applying to the drive circuit;
Search means for searching for a vibration suppression pulse condition in which the reverberation time is the shortest by measuring the reverberation time by the reverberation measurement means for each vibration suppression pulse applied to the drive circuit by the trial hitting means,
The damping means is searched by the searching means when the damping pulse condition searched by the searching means is different from the damping pulse condition stored in the first storage unit and the damping pulse condition selected by the selecting means. The vibration suppression pulse condition may be changed to apply the vibration suppression pulse to the drive circuit.

  By doing so, it is possible to apply a vibration suppression pulse to the drive circuit under the vibration suppression pulse condition in which the reverberation time retrieved based on the actual reverberation time is the shortest. In addition, since the trial hit is performed based on each vibration suppression pulse condition associated with a plurality of reverberation times within a predetermined time range, the trial hit can be performed with a certain range. Therefore, it is preferable because it is possible to search for a vibration suppression pulse condition in which the reverberation time is the shortest in a relatively short time and to surely shorten the reverberation time.

Similarly, as shown in claim 4,
Reverberation measuring means for measuring the reverberation time of the vibrator;
A plurality of combinations of ambient temperature, element constant, delay time, and pulse width, and a third storage unit that stores a plurality of reverberation times measured in advance in each combination,
The control circuit
Each damping pulse condition associated with a reverberation time within a predetermined time range is extracted from the third storage unit, and a transmission pulse and a damping pulse based on each damping pulse condition are extracted for each extracted damping pulse condition. Trial hitting means for applying to the drive circuit;
Search means for searching for a vibration suppression pulse condition in which the reverberation time is the shortest by measuring the reverberation time by the reverberation measurement means for each vibration suppression pulse applied to the drive circuit by the trial hitting means,
If the vibration suppression pulse condition searched by the search means is different from the vibration suppression pulse condition stored in the first storage unit, the vibration suppression means changes the vibration suppression pulse condition searched by the search means to the vibration suppression pulse condition. A pulse may be applied to the drive circuit. By doing so, the same effect as in the third aspect can be obtained.

In order to achieve the above object, an ultrasonic detection apparatus according to claim 5 is provided.
An ultrasonic detection device that performs a detection operation of detecting an object by transmitting an ultrasonic wave and receiving a reflected wave reflected from the object,
A transducer that transmits ultrasonic waves;
A drive circuit for driving the vibrator;
Controls driving of the vibrator by the driving circuit, and applies driving means for applying a transmission pulse for transmitting ultrasonic waves for detection from the vibrator to the driving circuit, and for suppressing reverberation of the vibrator. A control circuit including damping means for applying a damping pulse to the drive circuit after a predetermined time delay from the application of the transmission pulse;
Reverberation measuring means for measuring the reverberation time of the vibrator;
Multiple damping pulse conditions are stored, including the pulse width of the damping pulse corresponding to the element constants specific to the vibrator and drive circuit, and the delay time from the end of transmission pulse application timing as the damping pulse application timing. A fourth storage unit,
The pulse width and the delay time in each damping pulse condition stored in the fourth storage unit are values that make a reverberation time measured in advance within a predetermined range,
The control circuit
For each vibration suppression pulse condition stored in the fourth storage unit, trial hitting means for applying a transmission pulse and a vibration suppression pulse based on each vibration suppression pulse condition to the drive circuit;
Search means for searching for a vibration suppression pulse condition in which the reverberation time is the shortest by measuring the reverberation time by the reverberation measurement means for each vibration suppression pulse applied to the drive circuit by the trial hitting means,
The damping means applies the damping pulse to the drive circuit based on the damping pulse condition searched by the searching means.

  As described above, since the damping pulse is applied to the driving circuit based on the damping pulse condition corresponding to the element constant unique to the vibrator and the driving circuit, the element constants of the vibrator and the driving circuit vary. Even in this case, the reverberation time can be shortened. In other words, the reverberation time is shortened even when the element constants of the vibrator and drive circuit are different from a specific value, or when the combination of the vibrator and drive circuit is different from the combination of the specific vibrator and drive circuit. Can do. Further, the reverberation energy is smaller when the transmission pulse is delayed for a predetermined time than immediately after the transmission pulse is applied. Therefore, by applying a damping pulse with a predetermined time delay after the transmission pulse is applied in this way, the reverberation time can be reduced with a damping pulse having a smaller voltage than when the damping pulse is applied immediately after the transmission pulse is applied. It is efficient because it can be shortened.

  In addition, by doing in this way, it is possible to apply the vibration suppression pulse to the drive circuit under the vibration suppression pulse condition in which the reverberation time retrieved based on the actual reverberation time is the shortest. Furthermore, since trial strike is performed based on each vibration suppression pulse condition (pulse width, delay time) in which the reverberation time measured in advance is within a predetermined range, trial strike can be performed with a certain range narrowed down. Therefore, it is preferable because it is possible to search for a vibration suppression pulse condition in which the reverberation time is the shortest in a relatively short time and to surely shorten the reverberation time.

In order to achieve the above object, an ultrasonic detection apparatus according to claim 6 is provided.
An ultrasonic detection device that performs a detection operation of detecting an object by transmitting an ultrasonic wave and receiving a reflected wave reflected from the object,
A transducer that transmits ultrasonic waves;
A drive circuit for driving the vibrator;
Controls driving of the vibrator by the driving circuit, and applies driving means for applying a transmission pulse for transmitting ultrasonic waves for detection from the vibrator to the driving circuit, and for suppressing reverberation of the vibrator. A control circuit including damping means for applying a damping pulse to the drive circuit after a predetermined time delay from the application of the transmission pulse;
Temperature information acquisition means for acquiring temperature information indicating the ambient temperature;
Multiple damping pulse conditions are stored, including the pulse width of the damping pulse corresponding to the element constants specific to the vibrator and drive circuit, and the delay time from the end of transmission pulse application timing as the damping pulse application timing. A fifth storage unit,
Each vibration suppression pulse condition stored in the fifth storage unit includes the pulse width and delay time in which the reverberation time measured in advance for each ambient temperature falls within a predetermined range, and is associated with each ambient temperature. Remembered,
The control circuit includes a selection unit that selects a damping pulse condition corresponding to the temperature information acquired by the temperature information acquisition unit from the fifth storage unit,
The damping means applies the damping pulse to the drive circuit based on the damping pulse condition selected by the selection means.

  As described above, since the damping pulse is applied to the driving circuit based on the damping pulse condition corresponding to the element constant unique to the vibrator and the driving circuit, the element constants of the vibrator and the driving circuit vary. Even in this case, the reverberation time can be shortened. In other words, the reverberation time is shortened even when the element constants of the vibrator and drive circuit are different from a specific value, or when the combination of the vibrator and drive circuit is different from the combination of the specific vibrator and drive circuit. Can do. Further, the reverberation energy is smaller when the transmission pulse is delayed for a predetermined time than immediately after the transmission pulse is applied. Therefore, by applying a damping pulse with a predetermined time delay after the transmission pulse is applied in this way, the reverberation time can be reduced with a damping pulse having a smaller voltage than when the damping pulse is applied immediately after the transmission pulse is applied. It is efficient because it can be shortened.

  Further, even when the ambient temperature of the ultrasonic detection apparatus changes, it is possible to select a damping pulse condition that provides a predetermined reverberation time at that temperature. That is, it is possible to select a damping pulse condition that can shorten the reverberation time according to the ambient temperature. Since the vibration suppression pulse is applied to the drive circuit based on the vibration suppression pulse condition, it is possible to suppress an increase in the reverberation time even when the ambient temperature of the ultrasonic detection device changes. That is, it is possible to suppress an increase in reverberation time regardless of the ambient temperature.

In order to achieve the above object, an ultrasonic detection apparatus according to claim 7 is provided.
An ultrasonic detection device that performs a detection operation of detecting an object by transmitting an ultrasonic wave and receiving a reflected wave reflected from the object,
A transducer that transmits ultrasonic waves;
A drive circuit for driving the vibrator;
Controls driving of the vibrator by the driving circuit, and applies driving means for applying a transmission pulse for transmitting ultrasonic waves for detection from the vibrator to the driving circuit, and for suppressing reverberation of the vibrator. A control circuit including damping means for applying a damping pulse to the drive circuit after a predetermined time delay from the application of the transmission pulse;
Temperature information acquisition means for acquiring temperature information indicating the ambient temperature;
Reverberation measuring means for measuring the reverberation time of the vibrator;
Multiple damping pulse conditions are stored, including the pulse width of the damping pulse corresponding to the element constants specific to the vibrator and drive circuit, and the delay time from the end of transmission pulse application timing as the damping pulse application timing. A sixth storage unit,
The sixth storage unit includes a pulse width and a delay time in which a reverberation time measured in advance for each ambient temperature as a vibration suppression pulse condition is in a predetermined range. For each ambient temperature, each ambient temperature Are stored in association with a plurality of vibration suppression pulse conditions in which the reverberation time falls within a predetermined range,
The control circuit
Among a plurality of vibration suppression pulse conditions stored in the sixth storage unit, a plurality of vibration suppression pulse conditions corresponding to each piece of temperature information acquired by the temperature information acquisition means is based on the transmission pulse and each vibration suppression pulse condition. Trial hitting means for applying a vibration pulse to the drive circuit;
Search means for searching for a vibration suppression pulse condition in which the reverberation time is the shortest by measuring the reverberation time by the reverberation measurement means for each vibration suppression pulse applied to the drive circuit by the trial hitting means,
The damping means applies the damping pulse to the drive circuit based on the damping pulse condition searched by the searching means.

  As described above, since the damping pulse is applied to the driving circuit based on the damping pulse condition corresponding to the element constant unique to the vibrator and the driving circuit, the element constants of the vibrator and the driving circuit vary. Even in this case, the reverberation time can be shortened. In other words, the reverberation time is shortened even when the element constants of the vibrator and drive circuit are different from a specific value, or when the combination of the vibrator and drive circuit is different from the combination of the specific vibrator and drive circuit. Can do. Further, the reverberation energy is smaller when the transmission pulse is delayed for a predetermined time than immediately after the transmission pulse is applied. Therefore, by applying a damping pulse with a predetermined time delay after the transmission pulse is applied in this way, the reverberation time can be reduced with a damping pulse having a smaller voltage than when the damping pulse is applied immediately after the transmission pulse is applied. It is efficient because it can be shortened.

  In addition, by doing in this way, it is possible to apply the vibration suppression pulse to the drive circuit under the vibration suppression pulse condition in which the reverberation time retrieved based on the actual reverberation time is the shortest. In addition, since the test is performed based on each vibration suppression pulse condition (pulse width, delay time) in which the reverberation time measured in advance is within a predetermined range at the actual ambient temperature, the test is performed with a certain range narrowed down. Can do. Therefore, it is preferable because it is possible to search for a vibration suppression pulse condition in which the reverberation time is the shortest in a relatively short time and to surely shorten the reverberation time.

  Furthermore, even when the ambient temperature of the ultrasonic detector changes, it is possible to select a damping pulse condition that provides a predetermined reverberation time at that temperature. That is, it is possible to select a damping pulse condition that can shorten the reverberation time according to the ambient temperature. Since the vibration suppression pulse is applied to the drive circuit based on the vibration suppression pulse condition, it is possible to suppress an increase in the reverberation time even when the ambient temperature of the ultrasonic detection device changes. That is, it is possible to suppress an increase in reverberation time regardless of the ambient temperature.

1 is a block diagram illustrating a schematic configuration of an ultrasonic detection device according to a first embodiment of the present invention. (A)-(d) is a wave form diagram of each point at the time of not applying the vibration suppression pulse of the ultrasonic detection apparatus in 1st Embodiment of this invention. (A)-(d) is a wave form diagram of each point at the time of applying the damping pulse of the ultrasonic detector in 1st Embodiment of this invention. It is a graph which shows the characteristic of delay time and reverberation time in case the element constant of the ultrasonic detector in 1st Embodiment of this invention is typical (Typical). It is a graph which shows the characteristic of delay time and reverberation time in case the element constant of the ultrasonic detection apparatus in 1st Embodiment of this invention is the maximum (Max). It is a graph which shows the characteristic of delay time and reverberation time in case the element constant of the ultrasonic detection apparatus in 1st Embodiment of this invention is the minimum (Min). FIG. 6 is an enlarged view of a portion where the vibration damping effect of the graph in FIG. 5 is large. FIG. 7 is an enlarged view of a portion where the damping effect of the graph in FIG. 6 is large. 6 is a contour graph of a portion where the vibration damping effect of the graph in FIG. 5 is large. FIG. 7 is a contour graph of a portion where the vibration damping effect of the graph in FIG. 6 is large. 6 is a partial contour graph of the graph in FIG. FIG. 7 is a partial contour graph of the graph in FIG. 6. It is a graph which shows the characteristic of the reverberation time and temperature for every element constant when not applying the damping pulse of the ultrasonic detector in 1st Embodiment of this invention. It is an image figure of the element constant variation in the modification of this invention, and the damping-pulse comparison table. It is an image figure of the td-tw map in 2nd Embodiment of this invention. It is an image figure of the td-tw map in 3rd Embodiment of this invention. It is an image figure of the td-tw map in 4th Embodiment of this invention. It is a wave form diagram of a transmission pulse and a vibration suppression pulse of an ultrasonic detector in a modification.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
An ultrasonic detection apparatus 100 shown in FIG. 1 is mounted on a vehicle, and mainly includes a control circuit 10, a storage unit 20, a drive signal generation circuit 30, a drive circuit 40, a vibrator 50, an analog circuit 60, and the like. It is out. The control circuit in the claims of the present invention includes the control circuit 10 and the drive signal generation circuit 30.

  For example, a plurality of ultrasonic detection devices 100 are installed on a rear bumper of a vehicle. The ultrasonic detection apparatus 100 transmits ultrasonic waves (specifically, burst waves) from the vibrator 50 and receives reflected waves reflected from an object (for example, an obstacle) by the vibrator 50, thereby A detection operation for detecting presence / absence and a distance from an object is executed. As described above, the ultrasonic detection device 100 is a detection device that uses the transducer 50 for both transmission and reception.

  The ultrasonic detection apparatus 100 is electrically connected to an ECU (electronic control unit) 200 mounted on the vehicle. The ECU 200 is mainly composed of a microcomputer including a CPU, ROM, RAM, backup RAM, etc. (all not shown), and executes various processes by executing various control programs stored in the ROM. Is. For example, the ECU 200 acquires a signal related to the presence or absence of an object detected by the ultrasonic detection device 100 and a distance from the object, or instructs the ultrasonic detection device 100 to execute a diagnosis. The diagnosis in the ultrasonic detection apparatus 100 determines, for example, whether or not reverberation occurs when an ultrasonic wave is transmitted (transmitted) from the vibrator 50.

  Further, the ECU 200 outputs temperature information indicating the ambient temperature of the vehicle corresponding to the ambient temperature of the vibrator 50 to the ultrasonic detection device 100 (control circuit 10). That is, the ultrasonic detection apparatus 100 (control circuit 10) acquires temperature information indicating the ambient temperature of the vibrator 50 from the ECU 200 (temperature information acquisition means). A temperature sensor may be provided around the vibrator 50. That is, the control circuit 10 may acquire the detection result of the temperature sensor as temperature information indicating the ambient temperature (temperature information acquisition means).

  ECU 200 and ultrasonic detection device 100 are electrically connected by I / O 210 of ECU 200 and I / O 81 of ultrasonic detection device 100. Thereby, the ultrasonic detection apparatus 100 can exchange (transmit / receive) signals between the control circuit 10 and the ECU 200 via the I / O circuit 70. Further, the VCC 220 of the ECU 200 and the VCC 82 of the ultrasonic detection apparatus 100 are electrically connected to the GND 230 of the ECU 200 and the GND 83 of the ultrasonic detection apparatus 100. Accordingly, the ultrasonic detection apparatus 100 is supplied with power from the ECU 200.

  Here, the configuration of the ultrasonic detection apparatus 100 will be described in detail. The control circuit 10 is mainly composed of a microcomputer comprising a CPU, ROM, RAM, backup RAM, etc. (all not shown), and executes various processes by executing various control programs stored in the ROM. To do. For example, the control circuit 10 controls driving of the vibrator 50 by the drive circuit 40 via the drive signal generation circuit 30. That is, the control circuit 10 uses the transistor 31 provided in the drive signal generation circuit 30 to generate a pulse signal (transmission pulse, vibration suppression pulse) that is a drive signal, and sends this pulse signal to the drive circuit 40. Apply.

  Specifically, the control circuit 10 executes a process of applying a transmission pulse for transmitting a detection ultrasonic wave from the transducer 50 to the drive circuit 40 (drive means). Furthermore, a process of applying a damping pulse for suppressing the reverberation of the vibrator 50 (that is, shortening the reverberation time) to the drive circuit 40 with a predetermined time delay after applying the transmission pulse is executed (controlling). Shaking means). In other words, the control circuit 10 has a function of applying a transmission pulse for transmitting a detection ultrasonic wave from the vibrator 50 to the drive circuit 40 and a damping pulse for suppressing the reverberation of the vibrator 50. And a function of delaying a predetermined time after applying the transmission pulse and applying it to the drive circuit. The control circuit 10 applies a vibration suppression pulse to the drive circuit 40 based on the vibration suppression pulse condition stored in the storage unit 20. The vibration suppression pulse has a predetermined pulse width tw, and is applied to the drive circuit 40 when a predetermined delay time td has elapsed after the transmission pulse is applied.

  The control circuit 10 obtains the distance to the object and specifies the position of the obstacle based on the information on the ultrasonic wave transmitted (transmitted) from the transducer 50 and the information on the reflected wave from the object. Although detailed description is omitted, the control circuit 10 may execute processing according to information on the distance and position of the identified object. For example, when it is determined that an object is present in the vicinity of the vehicle, a warning is displayed on a display (not shown), or a warning is given by sounding a buzzer (not shown).

  In the storage unit 20 in the present embodiment, element constants specific to the drive circuit 40 measured in advance and element constants specific to the vibrator 50 measured in advance are stored (second storage unit). Hereinafter, the element constant specific to the drive circuit 40 measured in advance and the element constant specific to the vibrator 50 measured in advance are also simply referred to as element constants specific to the drive circuit 40 and the vibrator 50. However, the object of the present invention can be achieved without storing the inherent element constants. An example in which this unique element constant is not stored will be described later in another embodiment. The storage unit 20 can employ, for example, an EEPROM.

  Further, in the storage unit 20 in the present embodiment, a plurality of combinations of element constants of the drive circuit 40 and the vibrator 50, the ambient temperature of the vibrator 50, the delay time td, and the pulse width tw are measured in advance for each combination. A plurality of reverberation times are stored in association with each other (third storage unit). Therefore, the storage unit 20 stores the pulse width tw of the damping pulse set based on the element constant specific to the drive circuit 40 measured in advance and the element constant specific to the vibrator 50 measured in advance, and the damping pulse. A vibration suppression pulse condition including a delay time td from the end of transmission pulse application as the vibration pulse application timing is also stored (first storage unit). The damping pulse conditions (pulse width tw and delay time td) set based on the element constant specific to the drive circuit 40 measured in advance and the element constant specific to the vibrator 50 measured in advance are The reverberation time is set to be a predetermined value (that is, a predetermined value (allowable value) or less or the shortest). The damping pulse condition set based on the element constant specific to the drive circuit 40 measured in advance and the element constant unique to the vibrator 50 measured in advance can be rephrased as the initial value of the damping pulse condition. it can.

  The element constant specific to the drive circuit 40 measured in advance is an element constant specific to the drive circuit 40 mounted on the ultrasonic detection apparatus 100. Therefore, there is a possibility that the element constants are different between the drive circuits 40 mounted on different ultrasonic detection devices 100. Similarly, the element constant inherent to the transducer 50 measured in advance is an element constant inherent to the transducer 50 mounted on the ultrasonic detection apparatus 100. Therefore, there is a possibility that the element constants are different between the transducers 50 mounted on different ultrasonic detection apparatuses 100.

  Note that data in which a plurality of combinations of the ambient temperature, element constant, delay time td, and pulse width tw of the vibrator 50 and a plurality of reverberation times measured in advance in each combination are associated with each other is td (delay time). -It is called a tw (pulse width) map. Therefore, it can be said that the storage unit 20 stores the td-tw map. The td-tw map will be described in detail later.

  The drive circuit 40 includes a transistor 41, a capacitor C2, a transformer L2, and the like. The base terminal of the transistor 41 is electrically connected to the collector terminal of the transistor 31 of the drive signal generation circuit 30. The collector terminal of the transistor 41 is electrically connected to the primary side of the transformer L2, and the emitter terminal is connected to the power supply (VCC) side.

  The vibrator 50 is attached to a housing (not shown), and generates an ultrasonic wave by vibrating and receives a reflected wave reflected from an obstacle. As the vibrator 50, a piezoelectric vibrator or the like using a sintered body of piezoelectric ceramics such as PZT or barium titanate can be employed.

  The transmission signal (vibrator voltage) transmitted by the vibrator 50 and the received signal (vibrator voltage) acquired by the vibrator 50 are output to the analog circuit 60. The analog circuit 60 is generated by an amplification circuit 61 that amplifies a transmission signal and a reception signal, a comparison voltage generation circuit 62 that generates a comparison voltage, and a transmission signal and reception signal that are amplified by the amplification circuit 61 and a comparison voltage generation circuit 62. A comparison circuit 63 for comparing with the comparison voltage is provided. As a result of the comparison by the comparison circuit 63, the transmission signal amplified by the amplification circuit 61 is output to the control circuit 10.

  The vibrator 50 can be expressed as an equivalent circuit as shown in FIG. That is, as shown in FIG. 1, the vibrator 50 includes an equivalent series inductor L1 that is a component that serves as an equivalent series inductor, an equivalent series capacitor C1 that is a component that serves as an equivalent series capacitor, and an equivalent series. It can be expressed as a set of series resonant circuit composed of an equivalent series resistor R1 which is a component that serves as a resistor, and an equivalent parallel capacitor C0 that is a component that serves as an equivalent parallel capacitor. Further, the capacitor C2 and the transformer L2 in the drive circuit 40 are connected in parallel to the equivalent parallel capacitor C0.

  Usually, the element constants of the equivalent series inductor L1, equivalent series capacitor C1, equivalent series resistance R1, equivalent parallel capacitor C0, capacitor C2, and transformer L2 are determined so that the reverberation time is minimized at room temperature. However, these element constants vary within tolerances (that is, vary at the time of manufacturing. Hereinafter, they are also referred to as room temperature variations) and vary depending on the ambient temperature. When the element constant varies, as shown in FIG. 13, the reverberation time becomes longer even at room temperature, and the reverberation time becomes longer when the temperature falls below room temperature (low temperature) or when the temperature rises above room temperature (high temperature). There is. For example, when the reverberation standard of the ultrasonic detection apparatus is 1.6 ms or less, in the case of the example in FIG. 13, it may not be necessary to apply the vibration suppression pulse when the variation in the element constant is between −β to Typ to + α. I understand. However, in the case where the variation of the element constant is between Min and -β, and that of + α to Max, the reverberation needs to be reduced to 1.6 ms or less by some means.

  In particular, the element constant of the equivalent parallel capacitor C0 has a large variation in normal temperature and a large temperature fluctuation. Therefore, conventionally, for example, the transformer L2 is adjusted or the intersections of the element constants are narrowed at the time of manufacture so that the reverberation time is below a certain value at room temperature. However, even if the reverberation time at room temperature is set to a certain value or less, reverberation may increase at a low temperature or high temperature (the reverberation time becomes longer) due to temperature fluctuations of the vibrator 50 and the drive circuit 40. In the obstacle detection device field, generally, the time from the start of transmission of ultrasonic waves until the amplitude of the transducer 50 is attenuated to a constant value is referred to as reverberation time. Accordingly, the reverberation time is similarly defined in the present invention.

  Therefore, the ultrasonic detection apparatus 100 according to the present embodiment shortens the reverberation time by applying the damping pulse to the drive circuit 40 based on the damping pulse condition stored in the storage unit 20 as described above. It is something to be made.

  Here, the td-tw map will be described in detail. As described above, the td-tw map includes a plurality of combinations of the element constants of the drive circuit 40 and the vibrator 50, the ambient temperature of the vibrator 50, the delay time td, and the pulse width tw. Is associated with the reverberation time. That is, the reverberation time when the pulse width tw is changed at a predetermined interval at a certain element constant, a certain ambient temperature, and a certain delay time td is measured, and the element constant, ambient temperature, delay time td, and pulse width at this time are measured. tw and reverberation time are stored in association with each other. Then, the td-tw map is created by performing such measurement and storage by changing each of the element constant, the ambient temperature, and the delay time td. The td-tw map includes a plurality of combinations of the element constants of the drive circuit 40 and the vibrator 50, the ambient temperature of the vibrator 50, the delay time td, and the pulse width tw, and a plurality of reverberation times measured in advance for each combination. Any form can be adopted as long as is associated with.

  An example of the td-tw map will be described. First, three graphs in the case where the element constants are Typ, Max, and Min are shown in FIGS. That is, each graph in FIGS. 4 to 6 is a graph showing the characteristics of the delay time td and the reverberation time with the pulse width tw as a parameter in each element constant. The element constant Max is a maximum value including initial variation and temperature variation. That is, the initial constant variation is the maximum value, and the element constant at the maximum temperature in the temperature range in which the operation of the ultrasonic detection apparatus 100 is guaranteed. Similarly, the element constant Min is a minimum value including initial variation and temperature variation. That is, it is an element constant at a minimum temperature in a temperature range in which the initial variation is a minimum value and the operation of the ultrasonic detection apparatus 100 is guaranteed. On the other hand, the element constant Typ is a typical value at room temperature.

  Each of the graphs in FIGS. 4 to 6 is obtained by changing the pulse width tw from 0.1 μs to 8 μs in a 0.1 μs step, and 71 parameter line graphs are superimposed and displayed. The delay time td is recorded from 0 to 180 or 210 μs in 0.1 μs steps. In addition, the horizontal line in each graph of FIGS. 4-6 shows the reverberation time at the time of non-vibration suppression. Also, in each graph of FIGS. 4 to 6, the vertical axis represents the transmission pulse period of 15 μs step. In addition, 0-7.5, 15-22.5, 30-37.5.45-52.5 ... microsecond area | region is equivalent to a reverse phase.

  From these three graphs, it can be seen that immediately after the transmission pulse is applied (zero delay time), the effect of reducing the reverberation time (vibration effect) is small even when the vibration suppression pulse is applied. Further, from these three graphs, the delay time td having a large damping effect appears periodically, and in the case of the element constants Typ and Max, there is a damping effect by applying the positive phase. That is, it can also be seen that the delay time td, which has a large vibration damping effect, is not always in reverse phase.

  FIG. 7 is a graph obtained by enlarging the portion of the delay time td and the pulse width tw where the vibration damping effect of the graph in FIG. 5 is large. Similarly, FIG. 8 is a graph obtained by enlarging the portion of the delay time td and the pulse width tw where the vibration suppression effect of the graph in FIG. 6 is large. Such data is measured in advance, and for each combination of the element constant and the ambient temperature, the delay time td, the pulse width tw, and the reverberation time of the portion having a large damping effect are associated with each other to form a td-tw map. it can.

  FIG. 9 is a contour graph of a portion where the vibration damping effect of the graph in FIG. 5 is large. Similarly, FIG. 10 is a contour graph of a portion where the vibration damping effect of the graph in FIG. 6 is large. In this way, it is easy to create a td-tw map by measuring the data as described above in advance and plotting a contour graph of the portion where the damping effect is large for each combination of element constant and ambient temperature. Can do.

  For example, the td-tw map is a combination of element constants as shown in FIG. 14, vibration suppression pulse conditions (delay time td, pulse width tw) that minimize the reverberation time for each combination, and the vibration suppression pulse conditions. What was created at a plurality of ambient temperatures can be employed that is associated with the reverberation time of. That is, a table in which reverberation time is added to each damping pulse condition (delay time td, pulse width tw) is created for each ambient temperature (that is, for each predetermined temperature range) with respect to the table shown in FIG. One can be a td-tw map. Note that FIG. 14 used here for reference is an “element constant variation and damping pulse comparison table” in a modified example described later. In FIG. 14, the reverberation time under each vibration suppression pulse condition and the element constant of the equivalent series resistance R1 are omitted.

  Here, the characteristic part in the processing operation of the ultrasonic detection apparatus 100 in the present embodiment will be described.

  The control circuit 10 applies a pulse signal (transmission pulse) having a predetermined frequency instructed from the ECU 200 to the drive circuit 15 via the drive signal generation circuit 30 at a transmission timing instructed from the ECU 200. That is, a transmission pulse for transmitting a detection ultrasonic wave from the vibrator 50 is applied to the drive circuit 40 (drive means). The control circuit 10 applies a pulse signal (transmission pulse) of a predetermined frequency stored in the storage unit 20 to the drive circuit 15 via the drive signal generation circuit 30 at the transmission timing instructed from the ECU 200. You may do it.

  The drive circuit 40 is driven by receiving a power supply voltage (VCC) input to the ultrasonic detection device, and a drive frequency having a predetermined frequency is determined by a pulse signal from the control circuit 10 (drive signal generation circuit 30). Then, the vibrator 50 is driven (vibrated) to transmit ultrasonic waves. Note that the ECU 200 instructs the control circuit 10 to start the detection operation when the vehicle speed becomes slower than a predetermined value (for example, 10 km / h). Therefore, the control circuit 10 performs a detection operation when the vehicle speed is slower than a predetermined value (for example, 10 km / h or less). In other words, the control circuit 10 does not perform the detection operation when the vehicle speed is faster than a predetermined value (for example, 10 km / h).

  Further, the control circuit 10 applies a damping pulse to the drive circuit 40 based on the initial value of the damping pulse condition stored in the storage unit 20. That is, a damping pulse for suppressing the reverberation of the vibrator 50 is applied to the driving circuit 40 via the driving signal generating circuit 30 with a predetermined time delay after the transmission pulse is applied (damping means). As described above, the initial value of the damping pulse condition is a reverberation time that is less than or equal to a predetermined value (that is, a predetermined value (allowable value) or less) ) And a reverberation time of a predetermined value (that is, a predetermined value (allowable value) or shorter or the shortest) based on a pulse width tw set to be equal to) and an element constant specific to the vibrator and the drive circuit, which are measured in advance. And a delay time td set to be That is, in the ultrasonic detection apparatus 100, an initial value is set as a vibration suppression pulse condition at the time of manufacture.

  Here, the difference in reverberation time between when the damping pulse is applied and when it is not applied will be described. 2A to 2D are waveform diagrams of points in the block diagram when the vibration suppression pulse of the ultrasonic detection apparatus according to the embodiment of the present invention is not applied. On the other hand, FIGS. 3A to 3D are waveform diagrams at respective points in the block diagram when the vibration suppression pulse of the ultrasonic detection apparatus according to the embodiment of the present invention is applied. Specifically, FIGS. 2A to 2D and FIGS. 3A to 3D are waveform diagrams obtained by observing each point of the ultrasonic detection apparatus 100 with an oscilloscope. In each figure, the part indicated by “1” indicates the ground level, and the point indicated by “T” indicates a trigger (application start point of transmission pulse).

  2 (a) and 3 (a) are waveform diagrams (drive voltages) at point a in FIG. That is, it is a waveform diagram of a transmission pulse and a vibration suppression pulse. Therefore, the drive voltage is divided into a transmission pulse portion and a vibration suppression pulse portion. As shown in FIG. 3 (a), the damping pulse is applied as a pulse width tw after the delay time td after the application of the transmission pulse.

  FIGS. 2B and 3B are waveform diagrams (vibrator voltages) at point b in FIG. 1 when there is no object (obstacle). FIGS. 2C and 3C are waveform diagrams (amplified voltages) at point c in FIG. 1 when there is no object (obstacle). In this embodiment, the 1V cross time of this amplified voltage is set as the reverberation time. That is, the time from the start of transmission of ultrasonic waves until the amplification amplitude (envelope) of the transducer 50 is attenuated to 1 V is defined as the reverberation time.

  FIGS. 2D and 3D are waveform diagrams (amplified voltages) at point c in FIG. 1 when there is an object (obstacle). The right mountain in FIG. 2D and FIG. 3D is a waveform obtained by amplifying the reflected wave from the object. When the vibrator 50 is used for both transmission and reception, if the reverberation time becomes long, the reverberation and the reflected wave from the object are superimposed, and the reflected wave (object) cannot be detected accurately.

  However, as is apparent from FIGS. 2C and 3C, the ultrasonic detection apparatus 100 according to the present embodiment uses the vibration suppression pulse as the pulse width tw after the end of the application of the transmission pulse and after the delay time td. The reverberation time can be shortened by applying.

  In this way, the vibration suppression is set such that the reverberation time becomes a predetermined value (that is, the predetermined value (allowable value) or less or the shortest) based on the element constant inherent to the vibrator 50 and the drive circuit 40 measured in advance. Since the damping pulse is applied to the drive circuit 40 based on the pulse condition, the reverberation time can be shortened even when the element constants of the vibrator 50 and the drive circuit 40 vary. That is, even if the element constants of the vibrator 50 and the drive circuit 40 are different from the specific values, or even when the combination of the vibrator 50 and the drive circuit 40 is different from the combination of the specific vibrator and the drive circuit, the reverberation time. Can be shortened. Further, the reverberation energy is smaller when the transmission pulse is delayed for a predetermined time than immediately after the transmission pulse is applied. Therefore, by applying a damping pulse with a predetermined time delay after the transmission pulse is applied in this way, the reverberation time can be reduced with a damping pulse having a smaller voltage than when the damping pulse is applied immediately after the transmission pulse is applied. It is efficient because it can be shortened.

  Moreover, as for the ultrasonic detection apparatus 100 mounted in the vehicle, ambient temperature changes according to the environment where a vehicle exists. That is, the ambient temperature of the vibrator 50 also changes. Furthermore, as described above, the element constants of the vibrator 50 and the drive circuit 40 vary depending on the temperature. Therefore, when the ambient temperature of the ultrasonic detection apparatus 100 changes, the reverberation time also changes.

  Therefore, the control circuit 10 responds to the specific element constants of the drive circuit 40 and the vibrator 50 stored in the storage unit 20 and the temperature information acquired from the ECU 200 (that is, the current ambient temperature of the vibrator 50). From the td-tw map stored in the storage unit 20, the vibration suppression pulse condition that provides a predetermined reverberation time is selected (selection means). When the damping pulse condition selected based on the temperature information is different from the initial damping pulse condition, the control circuit 10 changes the damping pulse condition selected based on the temperature information to the damping pulse condition. You may make it apply with respect to the drive circuit 40. FIG. That is, basically, the damping pulse condition of the initial value is adopted, but the ambient temperature of the vibrator 50 (vehicle) changes and the damping pulse condition according to the current ambient temperature is different from the initial value. Adopts the damping pulse condition according to the current ambient temperature.

  In this way, even when the ambient temperature of the ultrasonic detection apparatus 100 changes, the reverberation time (that is, a predetermined value (allowable value) or less or the shortest reverberation time) is maintained at that temperature. The vibration pulse condition can be selected. That is, it is possible to select a damping pulse condition that can shorten the reverberation time according to the ambient temperature. Since the vibration suppression pulse is applied to the drive circuit 40 based on the vibration suppression pulse condition, it is possible to suppress an increase in the reverberation time even when the ambient temperature of the ultrasonic detection device 100 changes. That is, it is possible to suppress an increase in reverberation time regardless of the ambient temperature.

  The plurality of reverberation times in the td-tw map stored in the storage unit 20 includes a plurality of element constants of the vibrator 50 and the drive circuit 40, the ambient temperature of the vibrator, a delay time td, and a pulse width tw. It is measured in advance in combination. Therefore, the accuracy of the reverberation time depends on the number of combinations that are measured. Therefore, the reverberation time associated with the vibration suppression pulse condition in the td-tw map may be different from the actual reverberation time generated when the vibration suppression pulse is applied using this vibration suppression pulse condition.

  Therefore, the control circuit 10 measures the reverberation time of the vibrator 50 based on the transmission signal (transmission signal when the damping pulse is applied) amplified by the amplification circuit 61 of the analog circuit 60 (reverberation measuring means). . Further, the control circuit 10 extracts each damping pulse condition associated with the reverberation time within a predetermined time range from the td-tw map, and transmits the transmission pulse and each damping control for each extracted damping pulse condition. A vibration suppression pulse based on the pulse condition is applied to the drive circuit (trial driving means). That is, the control circuit 10 performs trial strikes of the transmission pulse and the damping pulse based on each damping pulse condition associated with the reverberation time within a predetermined time range. The reverberation time within a predetermined time range is a reverberation time within a time range that is less than or equal to a predetermined value (allowable value) or a reverberation time within a predetermined time range centered on the shortest reverberation time. It's time. The reason why the transmission pulse is applied here is not to transmit an ultrasonic wave for detecting an object, but to search for a vibration suppression pulse condition with the shortest reverberation time.

  Further, the control circuit 10 searches for a vibration suppression pulse condition that provides the shortest reverberation time by measuring the reverberation time for each vibration suppression pulse applied to the drive circuit 40 (search means). When the vibration suppression pulse condition searched in this way is different from the vibration suppression pulse condition selected in accordance with the initial value of the vibration suppression pulse condition and the ambient temperature, the control circuit 10 satisfies the searched vibration suppression pulse condition. Alternatively, the vibration suppression pulse may be applied to the drive circuit 40.

  As shown in FIG. 5, in the case of the element constant Max, the reverberation 1.911 ms during non-vibration becomes 1.098 ms when the pulse width tw = 6.6 μs and the delay time td = 205.6 μs, and 0.813 ms. There is a reduction effect. Even if the element constant fluctuates slightly from Max, for example, there are seven delay times td of 205.3 to 205.9 μs in 0.1 μs steps and pulse width tw of 6.3 to 6.9 μs in 0.1 μs steps. It can be seen that the delay time td and the pulse width tw with the shortest reverberation time can be obtained by trial-striking seven combinations, that is, 49 types of vibration suppression pulses.

  Further, as shown in FIG. 6, in the case of the element constant Min, the reverberation time 1.907 ms at the time of non-vibration becomes 1.183 ms when the pulse width tw = 4.4 μs and the delay time td = 153 μs, which is 0.714 ms. There is a reduction effect. Even if the element constant fluctuates slightly from Min, there are six delay times td of 152.8-153.3 μs in 0.1 μs steps, and seven pulse widths tw of 4.1-4.7 μs in 0.1 μs steps. It can be seen that a delay time td and a pulse width tw with the shortest reverberation time can be obtained by combining and combining 42 types of vibration suppression pulses.

  That is, as is apparent from the graphs shown in FIGS. 5 and 6, the reverberation time is the shortest in the delay time td and the pulse width tw. Further, the reverberation time becomes 1.6 ms or less due to the limited delay time td and pulse width tw. Therefore, as shown in FIGS. 7 and 8, the amount of data can be reduced by creating a td-tw map where the damping effect is large. Therefore, by using the td-tw map created with such a large vibration effect, it is possible to suppress the number of trial hits performed to find the optimum delay time td and pulse width tw.

  Similarly, in FIGS. 9 and 10, white has a reverberation time n of 1.6 ms or less, light gray has a reverberation time of 1.6 to 1.8 ms, and dark gray has a reverberation time of 1.8 to 2 ms. , Shows the pulse width tw. In FIG. 11 described later, black indicates a delay time td and a pulse width tw with a reverberation time of 2 ms or more. In the case of the element constants Max and Min, the pulse width tw = 6.6 μs, the delay time td = 205.6 μs, and the pulse width tw = 4.4 μs, the delay time td = 153 μs should have a large damping effect. I understand. In addition, the pulse width tw range and the delay time td range are well understood. Therefore, by trial-running the delay time td and pulse width tw in this white range, the number of trial strikes can be narrowed down, and the delay time td and pulse width tw with the shortest reverberation time can be quickly found.

  That is, as is clear from the contour graphs shown in FIGS. 11 and 12, the reverberation time is the shortest part of the delay time td and the pulse width tw. Further, the reverberation time becomes 1.6 ms or less due to the limited delay time td and pulse width tw. Therefore, as shown in FIGS. 9 and 10, the data amount can be reduced by creating a td-tw map where the vibration suppression effect is large. Therefore, by using the td-tw map created with such a large vibration effect, it is possible to suppress the number of trial hits performed to find the optimum delay time td and pulse width tw.

  By doing so, it is possible to apply a vibration suppression pulse to the drive circuit under the vibration suppression pulse condition in which the reverberation time retrieved based on the actual reverberation time is the shortest. In addition, since the trial hit is performed based on each vibration suppression pulse condition associated with a plurality of reverberation times within a predetermined time range, the trial hit can be performed with a certain range. Therefore, it is preferable because it is possible to search for a vibration suppression pulse condition in which the reverberation time is the shortest in a relatively short time and to surely shorten the reverberation time.

  Note that this trial hitting is preferably performed before a detection operation that does not hinder the detection operation performed by the ultrasonic detection apparatus 100 or during a pause of the detection operation. The ultrasonic detection apparatus 100 executes diagnosis for a predetermined period (for example, about 1 s) after the power is turned on. Therefore, the control circuit 10 does not perform the detection operation for a predetermined period after the power is turned on. Further, as described above, the control circuit 10 does not perform the detection operation when the vehicle speed is faster than a predetermined value (for example, 10 km / h). Therefore, when the control circuit 10 performs a trial hit when the vehicle speed is higher than a predetermined value (for example, 10 km / h) for a predetermined period (for example, about 1 s) after the power source is turned on. preferable.

  Further, this trial hitting can be executed during the detection operation if it does not interfere with the detection operation. That is, the trial strike can be executed if the timing is different from the application timing of the transmission pulse for detecting the object and the application timing of the vibration suppression pulse for reducing the reverberation time.

  By doing so, it is possible to search for the optimum vibration suppression pulse condition without hindering the detection operation.

  Further, since the ultrasonic detection apparatus 100 according to the present embodiment only changes the delay time td and the pulse width tw, it is not necessary to add hardware for vibration suppression, and the delay time is shortened with a very simple configuration. be able to. Furthermore, since the vibration can be controlled by the same voltage as the drive voltage, it is not necessary to change the applied voltage value for vibration control, and the circuit configuration can be simplified.

  In the present embodiment, a damping pulse is applied based on the damping pulse condition of the initial value, and the damping pulse condition is changed when a damping pulse condition different from the initial value is selected according to the ambient temperature. Furthermore, the description has been made by adopting an example in which the damping pulse condition is changed when a damping pulse condition different from the initial value and the selected damping pulse condition is detected according to the actual reverberation time. It is not limited.

  For example, the present invention provides a circuit for driving a damping pulse based on a damping pulse condition set based on an element constant specific to the driving circuit 40 measured in advance and an element constant unique to the vibrator 50 measured in advance. If it applies to 40 (modification 1), the object can be achieved. That is, the object can be achieved without changing the damping pulse condition according to the ambient temperature or the actual reverberation time.

  Specifically, only one set of delay time td and pulse width tw corresponding to the element constant is stored in the storage unit 20 (first storage unit). In this case, an “element constant variation and damping pulse comparison table” as shown in FIG. 14 is prepared in advance. In this comparison table, variations in element constants of the equivalent parallel capacitor C0, equivalent series capacitor C1, equivalent series inductor L1, capacitor C2, and transformer L2 are ranked. Here, the equivalent parallel capacitor C0 in which the element constant fluctuates most is divided into five ranks C01-1 to C01-5. The other equivalent series capacitor C1, equivalent series inductor L1, capacitor C2, and transformer L2 are each divided into three ranks (for example, L1-1 to L1-1). This comparison table shows various combinations of vibration suppression pulse conditions (delay time td, pulse width tw) for each combination of variations in element constants to create graphs of FIGS. 7 and 9, and the reverberation time is minimized from the graphs. The combinations are tabulated. That is, it can be created based on the above-described FIGS. In FIG. 14, “−” is given because there is no need to apply a damping pulse in the element combination with small variation. Further, the element constant of the equivalent series resistance R1 is omitted.

  The storage unit 20 selects and stores only one set of delay time td and pulse width tw from the comparison table at the time of manufacturing. As an example, the element constant of the equivalent parallel capacitor C0 is C0-1, the element constant of the equivalent series capacitor C1 is C1-3, the element constant of the equivalent series inductor L1 is L1-1, the element constant of the capacitor C2 is C2-1, When the element constant of the transformer L2 is L2-3, tw157 is selected as the pulse width and td157 is selected as the delay time, which are stored in the storage unit 20.

  As described above, the vibration suppression pulse is applied to the drive circuit based on the vibration suppression pulse condition (delay time td, pulse width tw) set based on the element constant inherent to the vibrator 50 and the drive circuit 40 measured in advance. Therefore, even if the element constants of the vibrator 50 and the drive circuit 40 vary, the reverberation time can be shortened. That is, even if the element constants of the vibrator 50 and the drive circuit 40 are different from the specific values, or the combination of the vibrator 50 and the drive circuit 40 is different from the combination of the specific vibrator and the drive circuit, the reverberation time. Can be shortened. Further, the reverberation energy is smaller when a predetermined time is delayed after the transmission pulse is applied than when the drive signal is supplied. Therefore, by applying a damping pulse with a predetermined time delay after the transmission pulse is applied in this way, the reverberation time can be reduced with a damping pulse having a smaller voltage than when the damping pulse is applied immediately after the drive signal is supplied. It is efficient because it can be shortened.

  In this case (in the case of Modification 1), the ultrasonic detection device 100 does not need to acquire temperature information indicating the ambient temperature described above. In other words, the ultrasonic detection apparatus 100 may not have the temperature information acquisition unit. Moreover, the ultrasonic detection apparatus 100 may not have a trial hitting unit. Further, the storage unit 20 may not store element constants specific to the drive circuit 40 measured in advance and element constants specific to the vibrator 50 measured in advance. That is, the second storage unit may not be included. Further, the storage unit 20 has a plurality of combinations of element constants of the drive circuit 40 and the vibrator 50, the ambient temperature of the vibrator 50, the delay time td, and the pulse width tw, and a plurality of reverberation times measured in advance in each combination. May not be stored. That is, the third storage unit may not be included.

  Further, the object can be achieved without changing the damping pulse condition according to the actual reverberation time (Modification 2). That is, the objective can be achieved even if the damping pulse condition is changed if a damping pulse condition different from the initial value is selected according to the ambient temperature.

  By doing so, even if the ambient temperature of the ultrasonic detection apparatus 100 changes, it is possible to select a damping pulse condition that provides a predetermined reverberation time at that temperature. That is, it is possible to select a damping pulse condition that can shorten the reverberation time according to the ambient temperature. Since the vibration suppression pulse is applied to the drive circuit 40 based on the vibration suppression pulse condition, it is possible to suppress an increase in the reverberation time even when the ambient temperature of the ultrasonic detection device 100 changes. That is, it is possible to suppress an increase in reverberation time regardless of the ambient temperature.

  Further, the object can be achieved without changing the damping pulse condition according to the ambient temperature (Modification 3). That is, the objective can be achieved even if the damping pulse condition is changed when a damping pulse condition different from the initial value is retrieved according to the actual reverberation time.

  By doing in this way, it is possible to apply the vibration suppression pulse to the drive circuit under the vibration suppression pulse condition that makes the shortest reverberation time searched based on the actual reverberation time. In addition, since the trial hit is performed based on each vibration suppression pulse condition associated with a plurality of reverberation times within a predetermined time range, the trial hit can be performed with a certain range. Therefore, it is preferable because it is possible to search for a vibration suppression pulse condition in which the reverberation time is the shortest in a relatively short time and to surely shorten the reverberation time.

(Second Embodiment)
In the above-described embodiment, the example in which the element constant is stored in the storage unit 20 is adopted, but the present invention is not limited to this. That is, as shown in the present embodiment, the storage unit 20 in the ultrasonic detection apparatus 100 may not store element constants specific to the transducer 50 and the drive circuit 40. In addition, the structure of the ultrasonic detection apparatus 100 in this embodiment is substantially the same as that of the above-mentioned embodiment. Therefore, detailed description of similar parts is omitted, and different points are mainly described. The difference between the present embodiment and the above-described embodiment is that the control circuit 10 does not acquire temperature information indicating the ambient temperature (that is, the temperature information acquisition unit is not included) and the storage contents of the storage unit 20. It is.

  In the storage unit 20 according to the present embodiment, the pulse width tw of the damping pulse corresponding to the element constants inherent to the vibrator 50 and the drive circuit 40 and the transmission pulse application timing as the damping pulse application timing are displayed. A plurality of damping pulse conditions including the delay time td are stored (fourth storage unit). Further, the pulse width tw and the delay time td in each vibration suppression pulse condition are values in which the reverberation time measured in advance is within a predetermined range (that is, a predetermined value or a predetermined value (allowable value) or less).

  Specifically, a td-tw map as shown in FIG. 15 is stored in the storage unit 20. The td-tw map shown in FIG. 15 is created based on, for example, the above-described FIGS. 4 to 12 and the like, and a plurality of damping pulse conditions (pulses) in which the reverberation time measured in advance is within a predetermined range. Width tw, delay time td). The td-tw map stored in the storage unit 20 corresponds to element constants specific to the transducer 50 and the drive circuit 40 mounted on the same ultrasonic detection apparatus 100 as the storage unit 20. In other words, the storage unit 20 has a plurality of vibration suppressions in which the reverberation time measured in advance using the vibrator 50 and the drive circuit 40 having unique element constants is a predetermined value (or a predetermined value (allowable value) or less). The pulse conditions (pulse width tw, delay time td) are stored. Therefore, the td-tw maps stored in the storage unit 20 are different between the ultrasonic detectors 100 in which the element constants of the mounted transducer 50 and the drive circuit 40 are different.

  Here, the characteristic part in the processing operation of the ultrasonic detection apparatus 100 in the present embodiment will be described.

  The control circuit 10 executes processing for applying a transmission pulse for transmitting ultrasonic waves for detection from the transducer 50 to the drive circuit 40 (drive means). Furthermore, a process of applying a damping pulse for suppressing the reverberation of the vibrator 50 (that is, shortening the reverberation time) to the drive circuit 40 with a predetermined time delay after applying the transmission pulse is executed (controlling). Shaking means). In other words, the control circuit 10 has a function of applying a transmission pulse for transmitting a detection ultrasonic wave from the vibrator 50 to the drive circuit 40 and a damping pulse for suppressing the reverberation of the vibrator 50. And a function of delaying a predetermined time after applying the transmission pulse and applying it to the drive circuit. It should be noted that the control circuit 10 uses the vibration suppression pulse conditions searched by performing trial hits based on the plurality of vibration suppression pulse conditions stored in the storage unit 20 to delay the transmission pulse for a predetermined time after application of the transmission pulse. A vibration pulse is applied to the drive circuit 40 (vibration control means). The vibration suppression pulse has a predetermined pulse width tw, and is applied to the drive circuit 40 when a predetermined delay time td has elapsed after the transmission pulse is applied.

  That is, the control circuit 10 applies a pulse signal (transmission pulse) having a frequency instructed from the ECU 200 to the drive circuit 15 via the drive signal generation circuit 30 at a transmission timing instructed from the ECU 200. That is, a transmission pulse for transmitting a detection ultrasonic wave from the vibrator 50 is applied to the drive circuit 40 (drive means). The control circuit 10 applies a pulse signal (transmission pulse) of a predetermined frequency stored in the storage unit 20 to the drive circuit 15 via the drive signal generation circuit 30 at the transmission timing instructed from the ECU 200. You may do it.

  The drive circuit 40 is driven by receiving a power supply voltage (VCC) input to the ultrasonic detection device, and a drive frequency having a predetermined frequency is determined by a pulse signal from the control circuit 10 (drive signal generation circuit 30). Then, the vibrator 50 is driven (vibrated) to transmit ultrasonic waves.

  Further, the control circuit 10 applies a transmission pulse and a damping pulse based on each damping pulse condition to the driving circuit for each damping pulse condition according to the td-tw map stored in the storage unit 20. (Trial hitting means). Furthermore, the control circuit 10 measures the reverberation time of the vibrator 50 based on the transmission signal (transmission signal when the damping pulse is applied) amplified by the amplification circuit 61 of the analog circuit 60 (reverberation measuring means). .

  Then, the control circuit 10 searches for a vibration suppression pulse condition that minimizes the reverberation time by measuring the reverberation time for each vibration suppression pulse applied to the drive circuit 40 (search means). Further, the control circuit 10 applies a vibration suppression pulse to the drive circuit 40 based on the vibration suppression pulse condition thus searched. That is, the control circuit 10 applies the damping pulse to the drive circuit 40 based on the searched damping pulse condition after applying the transmission pulse.

  As described above, since the damping pulse is applied to the driving circuit 40 based on the damping pulse condition corresponding to the element constants inherent to the vibrator 50 and the driving circuit 40, the elements of the vibrator 50 and the driving circuit 40 are used. Even if the constant varies, the reverberation time can be shortened. That is, even when the element constants of the vibrator 50 and the drive circuit 40 are different from specific values, or when the combination of the vibrator 50 and the drive circuit 40 is different from the combination of the specific vibrator 50 and the drive circuit 40, The reverberation time can be shortened. Further, the reverberation energy is smaller when the transmission pulse is delayed for a predetermined time than immediately after the transmission pulse is applied. Therefore, by applying a damping pulse with a predetermined time delay after the transmission pulse is applied in this way, the reverberation time can be reduced with a damping pulse having a smaller voltage than when the damping pulse is applied immediately after the transmission pulse is applied. It is efficient because it can be shortened.

  In addition, by doing in this way, it is possible to apply the vibration suppression pulse to the drive circuit 40 under the vibration suppression pulse condition that makes the search based on the actual reverberation time the shortest. Furthermore, since trial strike is performed based on each vibration suppression pulse condition (pulse width tw, delay time td) in which the reverberation time measured in advance is within a predetermined range, trial strike can be performed with a certain range narrowed down. Therefore, it is preferable because it is possible to search for a vibration suppression pulse condition in which the reverberation time is the shortest in a relatively short time and to surely shorten the reverberation time. Furthermore, the ultrasonic detection apparatus 100 according to the present embodiment does not need to store element constants specific to the transducer 50 and the drive circuit 40 in the storage unit 20.

(Third embodiment)
In the above-described embodiment, the example in which the element constant is stored in the storage unit 20 is adopted, but the present invention is not limited to this. That is, as shown in the present embodiment, the storage unit 20 in the ultrasonic detection apparatus 100 may not store element constants specific to the transducer 50 and the drive circuit 40. In addition, the structure of the ultrasonic detection apparatus 100 in this embodiment is substantially the same as that of the above-mentioned embodiment. Therefore, detailed description of similar parts is omitted, and different points are mainly described. The difference between the present embodiment and the above-described embodiment is the control circuit 10 that does not perform trial hitting (that is, a point that does not have trial hitting means) and the storage contents of the storage unit 20.

  In the storage unit 20 according to the present embodiment, the pulse width tw of the damping pulse corresponding to the element constants inherent to the vibrator 50 and the drive circuit 40 and the transmission pulse application timing as the damping pulse application timing are displayed. A plurality of damping pulse conditions including the delay time td are stored (fifth storage unit). In addition, the plurality of vibration suppression pulse conditions are such that a reverberation time measured in advance for each ambient temperature (that is, for each predetermined temperature range) is a predetermined range (that is, a predetermined value or a predetermined value (allowable value) or less). The pulse width tw and the delay time td are stored in association with each ambient temperature.

  Specifically, a td-tw map as shown in FIG. 16 is stored in the storage unit 20. Here, as shown in FIG. 16, 5 degreeC is employ | adopted as a predetermined temperature range. As shown in FIG. 16, the td-tw map (one example) in the present embodiment includes 22 vibration suppression pulse conditions in the range of the ambient temperature from −25 ° C. to 85 ° C.

  The td-tw map shown in FIG. 16 is created based on, for example, the above-described FIGS. 4 to 12 and the like, and is one vibration suppression in which the reverberation time measured in advance for each ambient temperature falls within a predetermined range. A pulse condition (a set of pulse width tw, delay time td) is associated with the ambient temperature. The td-tw map stored in the storage unit 20 corresponds to element constants specific to the transducer 50 and the drive circuit 40 mounted on the same ultrasonic detection apparatus 100 as the storage unit 20. In other words, the storage unit 20 includes a vibration suppression pulse condition (pulse width tw, delay time) in which a reverberation time measured in advance for each ambient temperature using the vibrator 50 and the drive circuit 40 having a specific element constant falls within a predetermined range. td) is stored for each ambient temperature. Therefore, the td-tw maps stored in the storage unit 20 are different between the ultrasonic detectors 100 in which the element constants of the mounted transducer 50 and the drive circuit 40 are different.

  When there are a plurality of vibration suppression pulse conditions (pulse width tw, delay time td) in which the reverberation time is in a predetermined range at a certain ambient temperature (temperature range), the vibration suppression pulse condition (pulse width) that minimizes the reverberation time. tw, delay time td) is adopted. Therefore, one damping pulse condition (a set of pulse width tw and delay time td) is associated with each ambient temperature in the td-tw map in the present embodiment.

  Here, the characteristic part in the processing operation of the ultrasonic detection apparatus 100 in the present embodiment will be described.

  The control circuit 10 executes processing for applying a transmission pulse for transmitting ultrasonic waves for detection from the transducer 50 to the drive circuit 40 (drive means). Furthermore, a process of applying a damping pulse for suppressing the reverberation of the vibrator 50 (that is, shortening the reverberation time) to the drive circuit 40 with a predetermined time delay after applying the transmission pulse is executed (controlling). Shaking means). In other words, the control circuit 10 has a function of applying a transmission pulse for transmitting a detection ultrasonic wave from the vibrator 50 to the drive circuit 40 and a damping pulse for suppressing the reverberation of the vibrator 50. And a function of delaying a predetermined time after applying the transmission pulse and applying it to the drive circuit. It should be noted that the control circuit 10 uses the vibration suppression pulse conditions searched by performing trial hits based on the plurality of vibration suppression pulse conditions stored in the storage unit 20 to delay the transmission pulse for a predetermined time after application of the transmission pulse. A vibration pulse is applied to the drive circuit 40 (vibration control means). The vibration suppression pulse has a predetermined pulse width tw, and is applied to the drive circuit 40 when a predetermined delay time td has elapsed after the transmission pulse is applied.

  That is, the control circuit 10 applies a pulse signal (transmission pulse) having a frequency instructed from the ECU 200 to the drive circuit 15 via the drive signal generation circuit 30 at a transmission timing instructed from the ECU 200. That is, a transmission pulse for transmitting a detection ultrasonic wave from the vibrator 50 is applied to the drive circuit 40 (drive means). The control circuit 10 applies a pulse signal (transmission pulse) of a predetermined frequency stored in the storage unit 20 to the drive circuit 15 via the drive signal generation circuit 30 at the transmission timing instructed from the ECU 200. You may do it.

  The drive circuit 40 is driven by receiving a power supply voltage (VCC) input to the ultrasonic detection device, and a drive frequency having a predetermined frequency is determined by a pulse signal from the control circuit 10 (drive signal generation circuit 30). Then, the vibrator 50 is driven (vibrated) to transmit ultrasonic waves.

  Further, the control circuit 10 selects a damping pulse condition from the td-tw map stored in the storage unit 20 according to the temperature information acquired from the ECU 200 (that is, the current ambient temperature of the vibrator 50) (selection). means). That is, the damping pulse condition associated with the current ambient temperature of the vibrator 50 is selected.

  Then, the control circuit 10 applies a vibration suppression pulse to the drive circuit 40 based on the vibration suppression pulse condition selected in this way. That is, the control circuit 10 applies the damping pulse to the drive circuit 40 based on the selected damping pulse condition after applying the transmission pulse.

  As described above, since the damping pulse is applied to the driving circuit 40 based on the damping pulse condition corresponding to the element constants inherent to the vibrator 50 and the driving circuit 40, the elements of the vibrator 50 and the driving circuit 40 are used. Even if the constant varies, the reverberation time can be shortened. That is, even when the element constants of the vibrator 50 and the drive circuit 40 are different from specific values, or when the combination of the vibrator 50 and the drive circuit 40 is different from the combination of the specific vibrator 50 and the drive circuit 40, The reverberation time can be shortened. Further, the reverberation energy is smaller when the transmission pulse is delayed for a predetermined time than immediately after the transmission pulse is applied. Therefore, by applying a damping pulse with a predetermined time delay after the transmission pulse is applied in this way, the reverberation time can be reduced with a damping pulse having a smaller voltage than when the damping pulse is applied immediately after the transmission pulse is applied. It is efficient because it can be shortened.

  Further, even when the ambient temperature of the ultrasonic detection apparatus 100 (vibrator 50) changes, it is possible to select a damping pulse condition that provides a predetermined reverberation time at that temperature. That is, it is possible to select a damping pulse condition that can shorten the reverberation time according to the ambient temperature. Since the damping pulse is applied to the drive circuit 40 based on this damping pulse condition, the reverberation time becomes long even when the ambient temperature of the ultrasonic detection device 100 (vibrator 50) changes. This can be suppressed. That is, it is possible to suppress an increase in reverberation time regardless of the ambient temperature.

  Furthermore, the ultrasonic detection device 100 according to the present embodiment has the optimal vibration suppression pulse condition (that is, the reverberation time is minimized in the surrounding environment of the current ultrasonic detection device 100), compared to the first and second embodiments described above. It is possible to reduce the time for searching for the vibration suppression pulse condition. Further, the damping pulse condition (that is, the data amount of the storage unit 20) stored in the storage unit 20 can be reduced as compared with the first and second embodiments. Further, it is not necessary to store element constants specific to the vibrator 50 and the drive circuit 40 in the storage unit 20.

(Fourth embodiment)
In the above-described embodiment, the example in which the element constant is stored in the storage unit 20 is adopted, but the present invention is not limited to this. That is, as shown in the present embodiment, the storage unit 20 in the ultrasonic detection apparatus 100 may not store element constants specific to the transducer 50 and the drive circuit 40. In addition, the structure of the ultrasonic detection apparatus 100 in this embodiment is the same as that of the above-mentioned embodiment. Therefore, detailed description of similar parts is omitted, and different points are mainly described. The difference between the present embodiment and the above-described embodiment is the storage content of the storage unit 20.

  In the storage unit 20 according to the present embodiment, the pulse width tw of the damping pulse corresponding to the element constants inherent to the vibrator 50 and the drive circuit 40 and the transmission pulse application timing as the damping pulse application timing are displayed. A plurality of damping pulse conditions including the delay time td are stored (sixth storage unit). Further, as the vibration suppression pulse condition, the reverberation time measured in advance for each ambient temperature (that is, for each predetermined temperature range) is within a predetermined range (that is, a predetermined value or a predetermined value (allowable value) or less). It includes a pulse width tw and a delay time td. Furthermore, a plurality of vibration suppression pulse conditions in which the reverberation time is in a predetermined range at each ambient temperature are associated with each ambient temperature.

  Specifically, a td-tw map as shown in FIG. 17 is stored in the storage unit 20. Here, as shown in FIG. 17, 5 ° C. is adopted as the predetermined temperature range. The ambient temperature is divided into 22 temperature ranges in the range of -25 ° C to 85 ° C. In addition, seven vibration suppression pulse conditions (pulse width tw, delay time td) are associated with each temperature range. Therefore, the td-tw map (an example) in the present embodiment includes a total of 154 vibration suppression pulse conditions.

  The td-tw map shown in FIG. 17 is created based on, for example, the above-described FIGS. 4 to 12 and the like, and a plurality of vibration suppressions in which the reverberation time measured in advance for each ambient temperature falls within a predetermined range. A pulse condition (a plurality of sets of pulse widths tw and delay time td) is associated with the ambient temperature. The td-tw map stored in the storage unit 20 corresponds to element constants specific to the transducer 50 and the drive circuit 40 mounted on the same ultrasonic detection apparatus 100 as the storage unit 20. That is, the storage unit 20 includes a plurality of vibration suppression pulse conditions (a plurality of sets of pulses) in which the reverberation time measured in advance for each ambient temperature using the vibrator 50 and the drive circuit 40 having unique element constants is within a predetermined range. The width tw and the delay time td) are stored for each ambient temperature. Therefore, the td-tw maps stored in the storage unit 20 are different between the ultrasonic detectors 100 in which the element constants of the mounted transducer 50 and the drive circuit 40 are different.

  Here, the characteristic part in the processing operation of the ultrasonic detection apparatus 100 in the present embodiment will be described.

  The control circuit 10 executes processing for applying a transmission pulse for transmitting ultrasonic waves for detection from the transducer 50 to the drive circuit 40 (drive means). Furthermore, a process of applying a damping pulse for suppressing the reverberation of the vibrator 50 (that is, shortening the reverberation time) to the drive circuit 40 with a predetermined time delay after applying the transmission pulse is executed (controlling). Shaking means). In other words, the control circuit 10 has a function of applying a transmission pulse for transmitting a detection ultrasonic wave from the vibrator 50 to the drive circuit 40 and a damping pulse for suppressing the reverberation of the vibrator 50. And a function of delaying a predetermined time after applying the transmission pulse and applying it to the drive circuit. It should be noted that the control circuit 10 uses the vibration suppression pulse conditions searched by performing trial hits based on the plurality of vibration suppression pulse conditions stored in the storage unit 20 to delay the transmission pulse for a predetermined time after application of the transmission pulse. A vibration pulse is applied to the drive circuit 40 (vibration control means). The vibration suppression pulse has a predetermined pulse width tw, and is applied to the drive circuit 40 when a predetermined delay time td has elapsed after the transmission pulse is applied.

  That is, the control circuit 10 applies a pulse signal (transmission pulse) having a frequency instructed from the ECU 200 to the drive circuit 15 via the drive signal generation circuit 30 at a transmission timing instructed from the ECU 200. That is, a transmission pulse for transmitting a detection ultrasonic wave from the vibrator 50 is applied to the drive circuit 40 (drive means). The control circuit 10 applies a pulse signal (transmission pulse) of a predetermined frequency stored in the storage unit 20 to the drive circuit 15 via the drive signal generation circuit 30 at the transmission timing instructed from the ECU 200. You may do it.

  The drive circuit 40 is driven by receiving a power supply voltage (VCC) input to the ultrasonic detection device, and a drive frequency having a predetermined frequency is determined by a pulse signal from the control circuit 10 (drive signal generation circuit 30). Then, the vibrator 50 is driven (vibrated) to transmit ultrasonic waves.

  Further, the control circuit 10 selects a plurality of vibration suppression pulse conditions from the td-tw map stored in the storage unit 20 in accordance with the temperature information acquired from the ECU 200 (that is, the current ambient temperature of the vibrator 50). (Selection means). That is, a plurality of vibration suppression pulse conditions associated with the current ambient temperature of the vibrator 50 are selected.

  The control circuit 10 applies a transmission pulse and a vibration suppression pulse based on each vibration suppression pulse condition to the drive circuit for each vibration suppression pulse condition selected from the td-tw map stored in the storage unit 20. (Trial hitting means). The control circuit 10 measures the reverberation time of the vibrator 50 based on the transmission signal (transmission signal when the damping pulse is applied) amplified by the amplification circuit 61 of the analog circuit 60 (reverberation measuring means). .

  Then, the control circuit 10 searches for a vibration suppression pulse condition that minimizes the reverberation time by measuring the reverberation time for each vibration suppression pulse applied to the drive circuit 40 (search means). Further, the control circuit 10 applies a vibration suppression pulse to the drive circuit 40 based on the vibration suppression pulse condition thus searched. That is, the control circuit 10 applies the damping pulse to the drive circuit 40 based on the searched damping pulse condition after applying the transmission pulse.

  As described above, since the damping pulse is applied to the driving circuit 40 based on the damping pulse condition corresponding to the element constants inherent to the vibrator 50 and the driving circuit 40, the elements of the vibrator 50 and the driving circuit 40 are used. Even if the constant varies, the reverberation time can be shortened. That is, even when the element constants of the vibrator 50 and the drive circuit 40 are different from specific values, or when the combination of the vibrator 50 and the drive circuit 40 is different from the combination of the specific vibrator 50 and the drive circuit 40, The reverberation time can be shortened. Further, the reverberation energy is smaller when the transmission pulse is delayed for a predetermined time than immediately after the transmission pulse is applied. Therefore, by applying a damping pulse with a predetermined time delay after the transmission pulse is applied in this way, the reverberation time can be reduced with a damping pulse having a smaller voltage than when the damping pulse is applied immediately after the transmission pulse is applied. It is efficient because it can be shortened.

  In addition, by doing in this way, it is possible to apply the vibration suppression pulse to the drive circuit 40 under the vibration suppression pulse condition that makes the search based on the actual reverberation time the shortest. In addition, since the test is performed based on each vibration suppression pulse condition (pulse width, delay time) in which the reverberation time measured in advance is within a predetermined range at the actual ambient temperature, the test is performed with a certain range narrowed down. Can do. Therefore, it is preferable because it is possible to search for a vibration suppression pulse condition in which the reverberation time is the shortest in a relatively short time and to surely shorten the reverberation time.

  Furthermore, even when the ambient temperature of the ultrasonic detection apparatus 100 (vibrator 50) changes, it is possible to select a damping pulse condition that provides a predetermined reverberation time at that temperature. That is, it is possible to select a damping pulse condition that can shorten the reverberation time according to the ambient temperature. Since the damping pulse is applied to the drive circuit 40 based on this damping pulse condition, the reverberation time becomes long even when the ambient temperature of the ultrasonic detection device 100 (vibrator 50) changes. This can be suppressed. That is, it is possible to suppress an increase in reverberation time regardless of the ambient temperature.

  Furthermore, the ultrasonic detection apparatus 100 according to the present embodiment does not need to store element constants specific to the transducer 50 and the drive circuit 40 in the storage unit 20.

(Other variations)
In the above-described embodiment, the example in which the damping pulse is applied only once after the application of the transmission pulse as shown in FIG. 3A has been described, but the present invention is not limited to this. Absent. In the present invention, as shown in FIG. 18, the damping pulse may be applied a plurality of times after the application of the transmission pulse. That is, after the application of the transmission pulse, the first damping pulse having the pulse width tw1 is applied after the delay time td1 has elapsed. Further, after the application of the first damping pulse, the second damping pulse having the pulse width tw2 is applied after the delay time td2 has elapsed. Then, the nth damping pulse (the nth damping pulse) is applied as a pulse width twn after the delay time tdn after the application of the previous damping pulse (n−1th damping pulse) is finished (n Is a natural number).

  As mentioned above, although preferable embodiment of this invention was described, this invention is not restrict | limited to the embodiment mentioned above at all, and various deformation | transformation are possible in the range which does not deviate from the meaning of this invention.

  10 control circuit, 20 storage unit, 30 drive signal generation circuit, 40 drive circuit, C2 capacitor, L2 transformer, 50 oscillator, L1 equivalent series inductor, C1 equivalent series capacitor, R1 equivalent series resistance, C0 equivalent parallel capacitor, 60 analog Circuit, 100 ultrasonic detector

Claims (7)

An ultrasonic detection device that performs a detection operation of detecting an object by transmitting an ultrasonic wave and receiving a reflected wave reflected from the object,
A transducer that transmits ultrasonic waves;
A drive circuit for driving the vibrator;
Drive means for controlling the drive of the vibrator by the drive circuit, drive means for applying a transmission pulse for transmitting ultrasonic waves for detection from the vibrator to the drive circuit, and reverberation of the vibrator A control circuit including a vibration suppression means for applying a vibration suppression pulse for suppressing the transmission circuit to the drive circuit with a predetermined time delay after application of the transmission pulse;
As the reverberation time is set to a predetermined value based on element constants specific to the vibrator and the drive circuit measured in advance, the pulse width of the damping pulse and the application timing of the damping pulse are as follows: A first storage unit that stores a damping pulse condition including a delay time from the end of application of the transmission pulse, and
The ultrasonic detection device, wherein the vibration suppression unit applies the vibration suppression pulse to the drive circuit based on the vibration suppression pulse condition stored in the first storage unit. Temperature information acquisition means for acquiring temperature information indicating the ambient temperature;
A second storage unit in which element constants specific to the vibrator and the drive circuit measured in advance are stored;
A plurality of combinations of ambient temperature, element constant, delay time, and pulse width, and a third storage unit that stores a plurality of reverberation times measured in advance in each combination,
The control circuit selects a damping pulse condition that provides a predetermined reverberation time from the third storage unit according to the element constant stored in the second storage unit and the temperature information acquired by the temperature information acquisition unit. Including selection means to
The vibration damping means, if the vibration suppression pulse condition selected by the selection means is different from the vibration suppression pulse condition stored in the first storage unit, the vibration suppression pulse selected by the selection means. 2. The ultrasonic detection apparatus according to claim 1, wherein the vibration control pulse is changed to a pulse condition and applied to the drive circuit. Reverberation measuring means for measuring the reverberation time of the vibrator,
The control circuit includes:
Each damping pulse condition associated with a reverberation time within a predetermined time range is extracted from the third storage unit, and the damping pulse condition based on the transmission pulse and each damping pulse condition is extracted for each extracted damping pulse condition. Trial hitting means for applying a vibration pulse to the drive circuit;
Search means for searching for a damping pulse condition that makes the reverberation time shortest by measuring the reverberation time by the reverberation measuring means for each damping pulse applied to the drive circuit by the trial hitting means; Including,
The vibration damping means, when the vibration suppression pulse condition searched by the search means is different from the vibration suppression pulse condition stored in the first storage unit and the vibration suppression pulse condition selected by the selection means The ultrasonic detection apparatus according to claim 2, wherein the damping pulse condition is changed to the damping pulse condition searched by the search means and the damping pulse is applied to the drive circuit. Reverberation measuring means for measuring the reverberation time of the vibrator;
A plurality of combinations of ambient temperature, element constant, delay time, and pulse width, and a third storage unit that stores a plurality of reverberation times measured in advance in each combination,
The control circuit includes:
Each damping pulse condition associated with a reverberation time within a predetermined time range is extracted from the third storage unit, and the damping pulse condition based on the transmission pulse and each damping pulse condition is extracted for each extracted damping pulse condition. Trial hitting means for applying a vibration pulse to the drive circuit;
Search means for searching for a damping pulse condition that makes the reverberation time shortest by measuring the reverberation time by the reverberation measuring means for each damping pulse applied to the drive circuit by the trial hitting means; Including,
The vibration damping means, when the vibration suppression pulse condition searched by the search means is different from the vibration suppression pulse condition stored in the first storage unit, the vibration suppression pulse searched by the search means The ultrasonic detection apparatus according to claim 1, wherein the vibration suppression pulse is applied to the drive circuit while changing to a condition. An ultrasonic detection device that performs a detection operation of detecting an object by transmitting an ultrasonic wave and receiving a reflected wave reflected from the object,
A transducer that transmits ultrasonic waves;
A drive circuit for driving the vibrator;
Drive means for controlling the drive of the vibrator by the drive circuit, drive means for applying a transmission pulse for transmitting ultrasonic waves for detection from the vibrator to the drive circuit, and reverberation of the vibrator A control circuit including a vibration suppression means for applying a vibration suppression pulse for suppressing the transmission circuit to the drive circuit with a predetermined time delay after application of the transmission pulse;
Reverberation measuring means for measuring the reverberation time of the vibrator;
A damping pulse including a pulse width of the damping pulse corresponding to an element constant unique to the vibrator and the driving circuit, and a delay time from the end of application of the transmission pulse as application timing of the damping pulse A fourth storage unit in which a plurality of conditions are stored,
The pulse width and the delay time in each vibration suppression pulse condition stored in the fourth storage unit are values within a predetermined range of reverberation time measured in advance,
The control circuit includes:
For each vibration suppression pulse condition stored in the fourth storage unit, trial hitting means for applying the vibration suppression pulse based on the transmission pulse and each vibration suppression pulse condition to the drive circuit;
Search means for searching for a damping pulse condition that makes the reverberation time shortest by measuring the reverberation time by the reverberation measuring means for each damping pulse applied to the drive circuit by the trial hitting means; Including,
The ultrasonic detection apparatus, wherein the vibration suppression unit applies the vibration suppression pulse to the drive circuit based on the vibration suppression pulse condition searched by the search unit. An ultrasonic detection device that performs a detection operation of detecting an object by transmitting an ultrasonic wave and receiving a reflected wave reflected from the object,
A transducer that transmits ultrasonic waves;
A drive circuit for driving the vibrator;
Drive means for controlling the drive of the vibrator by the drive circuit, drive means for applying a transmission pulse for transmitting ultrasonic waves for detection from the vibrator to the drive circuit, and reverberation of the vibrator A control circuit including a vibration suppression means for applying a vibration suppression pulse for suppressing the transmission circuit to the drive circuit with a predetermined time delay after application of the transmission pulse;
Temperature information acquisition means for acquiring temperature information indicating the ambient temperature;
A damping pulse including a pulse width of the damping pulse corresponding to an element constant unique to the vibrator and the driving circuit, and a delay time from the end of application of the transmission pulse as application timing of the damping pulse A fifth storage unit in which a plurality of conditions are stored,
Each vibration suppression pulse condition stored in the fifth storage unit includes the pulse width and the delay time in which the reverberation time measured in advance for each ambient temperature falls within a predetermined range. Associated and remembered,
The control circuit includes a selection unit that selects a damping pulse condition corresponding to the temperature information acquired by the temperature information acquisition unit from the fifth storage unit,
The ultrasonic detection apparatus, wherein the vibration suppression unit applies the vibration suppression pulse to the drive circuit based on the vibration suppression pulse condition selected by the selection unit. An ultrasonic detection device that performs a detection operation of detecting an object by transmitting an ultrasonic wave and receiving a reflected wave reflected from the object,
A transducer that transmits ultrasonic waves;
A drive circuit for driving the vibrator;
Drive means for controlling the drive of the vibrator by the drive circuit, drive means for applying a transmission pulse for transmitting ultrasonic waves for detection from the vibrator to the drive circuit, and reverberation of the vibrator A control circuit including a vibration suppression means for applying a vibration suppression pulse for suppressing the transmission circuit to the drive circuit with a predetermined time delay after application of the transmission pulse;
Temperature information acquisition means for acquiring temperature information indicating the ambient temperature;
Reverberation measuring means for measuring the reverberation time of the vibrator;
A damping pulse including a pulse width of the damping pulse corresponding to an element constant unique to the vibrator and the driving circuit, and a delay time from the end of application of the transmission pulse as application timing of the damping pulse A sixth storage unit in which a plurality of conditions are stored,
The sixth storage unit includes, as the vibration suppression pulse condition, the pulse width and the delay time in which a reverberation time measured in advance for each ambient temperature falls within a predetermined range, and for each ambient temperature A plurality of vibration suppression pulse conditions that have a reverberation time within a predetermined range at each ambient temperature are associated and stored,
The control circuit includes:
Among the plurality of vibration suppression pulse conditions stored in the sixth storage unit, the transmission pulse and each vibration suppression pulse condition in the plurality of vibration suppression pulse conditions corresponding to each temperature information acquired by the temperature information acquisition unit Trial hitting means for applying the damping pulse based on the driving circuit to the drive circuit;
Search means for searching for a damping pulse condition that makes the reverberation time shortest by measuring the reverberation time by the reverberation measuring means for each damping pulse applied to the drive circuit by the trial hitting means; Including,
The ultrasonic detection apparatus, wherein the vibration suppression unit applies the vibration suppression pulse to the drive circuit based on the vibration suppression pulse condition searched by the search unit.

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