JP2009198222A - Detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a contact detector which can acquire an output signal, without suppressing the vibration of a vibrating plate. <P>SOLUTION: When a detecting plate 120, which functions as a vibrating plate, is fixed to a case 110, the peripheral area of the detecting plate 120 is partially fixed through spacers 130a, 130b. Since the peripheral area of the detecting plate 120 as a whole is not fixed to the case 110, suppression of vibration is prevented. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a detection device that detects contact of an object to be contacted with a diaphragm.

Conventionally, there are many devices that vibrate a diaphragm and perform various processes using the vibration. In an apparatus using such vibration, there are cases where the outer peripheral region of a diaphragm to which a vibrator such as a piezoelectric element is fixed is fixed to a case body or the like. For example, Patent Document 1 describes that the peripheral portion of the diaphragm is supported by a step-shaped support portion provided in the case.
Japanese Patent Laid-Open No. 2002-238094

  However, in the above conventional technique, since the outer peripheral region of the diaphragm is fixed, the vibration of the diaphragm is suppressed and the level of the output signal due to the vibration is lowered. For example, if the device using vibration is a device that determines whether or not an object is in contact with the diaphragm due to the vibration change of the diaphragm, it is difficult to detect the vibration change when the level of the output signal decreases. It becomes.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a detection device capable of acquiring an output signal without suppressing vibration of the diaphragm. It is.

  The present invention employs the following configuration in order to achieve the above object.

The detection device of the present invention is a detection device (100) that includes a case body (110) and a diaphragm (120), and detects contact of an object to be contacted with the diaphragm (120).
The diaphragm (120)
A part of the outer peripheral region of the diaphragm (120) is fixed to the case body (110) via a clamping member (130a, 130b) disposed between the diaphragm (120) and the case body (110). .

In the detection device of the present invention, a plurality of the clamping members (130a, 130b) are arranged between the outer peripheral region and the case body (110),
The outer peripheral region of the diaphragm (120) may be configured to be fixed to the case body (110) via a plurality of the clamping members (130a, 130b) arranged.

  In the detection device of the present invention, the material forming the clamping members (130a, 130b) may be harder than the material forming the diaphragm (120).

In the detection device of the present invention, the piezoelectric element (140) fixed to the diaphragm (120),
A detection circuit (300) for detecting a change in a voltage signal output from the piezoelectric element (140);
The detection circuit (300)
Storage means (352) for storing a waveform of a voltage signal when there is no contact of an object to be contacted with the diaphragm (120);
Acquisition means (354) for acquiring a waveform of a voltage signal output from the piezoelectric element (140);
Comparing means (355) for comparing the waveform stored in the storage means with the waveform of the voltage signal acquired by the acquiring means,
It is good also as a structure which detects the contact of the to-be-contacted object with respect to the said diaphragm (120) based on the comparison result by the said comparison means (355).

  Note that the reference numerals in the parentheses are given for ease of understanding, are merely examples, and are not limited to the illustrated modes.

  According to the present invention, an output signal can be acquired without suppressing vibration of the diaphragm.

In the present invention, when the diaphragm is fixed to the case body, the outer peripheral region of the diaphragm is partially fixed via the clamping member. According to the present invention, since the entire outer peripheral area of the diaphragm is not fixed to the case body, it is possible to prevent vibrations from being suppressed.
(First embodiment)
A first embodiment of the present invention will be described below with reference to the drawings. In the present embodiment, a water droplet detection device that is an embodiment of the contact detection device of the present invention will be described. The water droplet detection device of this embodiment is a device that detects whether or not a water droplet has contacted the diaphragm.

  FIG. 1 is a perspective view showing a water droplet detection device 100 of the first embodiment. The water droplet detection device 100 according to the present embodiment includes a detection plate 120 in which a detection region 120A is exposed from the case body 110.

  The case body 110 of the present embodiment includes a circuit housing part 111 and a lid part 112. The circuit storage unit 111 stores a circuit for detecting water droplets. The lid portion 112 serves as a lid for the circuit storage portion 111. Further, the circuit housing portion 111 and the lid portion 112 of the case body 110 of the present embodiment are formed with frame portions 113a and 113b surrounding the detection region 120A and cutout portions 114a and 114b for exposing the detection region 120A, respectively. . The frame portions 113a and 113b and the cutout portions 114a and 114b are formed so that when the lid portion 112 is put on the circuit storage portion 111, the detection regions 120A are exposed.

  The detection plate 120 of the present embodiment is a plate in which a piezoelectric element described later is bonded to a transparent plate, for example, and functions as a vibration plate. The detection plate 120 of this embodiment is a glass plate to which a piezoelectric element is bonded. The piezoelectric element is bonded to a portion other than the exposed surface 120A of the detection plate 120.

  In the water droplet detection device 100 of the present embodiment, the piezoelectric element is vibrated in advance by a circuit stored in the circuit storage unit 111, and the detection region 120A when the water droplet adheres to the detection region 120A to which the vibration of the piezoelectric element has been propagated. The adhesion (contact) of water droplets is detected based on the change in vibration.

  Next, a method for fixing the detection plate 120 in the water droplet detection device 100 of the present embodiment will be described with reference to FIG. FIG. 2 is a diagram illustrating a method for fixing the detection plate 120. 2A is a top perspective view of the water droplet detection device 100, and FIG. 2B is a cross-sectional view taken along the line AA of the water droplet detection device 100. FIG.

  The detection plate 120 of this embodiment is sandwiched so that the detection region 120A is exposed. The detection area 120A is an area exposed from the cutout portions 114a and 114b in the detection plate 120. The detection region 120A may be determined in consideration of, for example, the purpose for installing the water droplet detection device 100 of the present embodiment. For example, when the water droplet detection device 100 of the present embodiment is installed for the purpose of detecting raindrops, it is preferable that the detection region 120A is wider because raindrop detection can be performed over a wide range. In addition, when the water droplet detection device 100 of the present embodiment is set for the purpose of specifying the position where the water droplet has dropped, it is preferable that the detection region 120A is narrower because the position can be specified more precisely.

  In addition, the piezoelectric element 140 is bonded and fixed to the detection plate 120 in a region other than the detection region 120A. The piezoelectric element 140 is preferably bonded so as to be in close contact with the detection plate 120. The piezoelectric element 140 is connected to a drive circuit and a detection circuit described later, and is driven based on a signal from the drive circuit.

  In addition, the detection plate 120 of the present embodiment is sandwiched between the clamping member 130b provided in the circuit storage unit 111 and the clamping member 130a (see FIG. 2B) provided in the lid part 112 in the outer peripheral region. . The outer peripheral area of the detection plate 120 indicates, for example, an area outside the detection area 120A and overlapping with the frame portions 113a and 113b.

  In the present embodiment, since the detection plate 120 is sandwiched between the sandwiching members 130a and 130b in this way, the detection plate 120 does not touch the case body 110 (the circuit housing portion 111 and the lid portion 112). Therefore, in the present embodiment, the vibration transmitted from the piezoelectric element 140 to the detection plate 120 is not suppressed by directly fixing the detection plate 120 to the case body 110.

  In addition, the detection plate 120 of the present embodiment has an outer peripheral region partially sandwiched between the sandwiching members 130a and 130b. Therefore, in this embodiment, the vibration propagated to the detection plate 120 is not suppressed compared to a state where the entire outer peripheral region of the detection plate 120 is fixed. For this reason, in this embodiment, a minute change in vibration of the detection plate 120 can be detected.

  In the present embodiment, it is preferable that the sandwiching members 130 a and 130 b are formed of a material harder than the detection plate 120. For example, when the detection plate 120 of this embodiment is glass, it is preferable that the clamping members 130a and 130b are made of metal or the like. When the sandwiching members 130a and 130b are formed of a member that is harder than the detection plate 120, vibration (surface acoustic waves) propagated to the detection plate 120 is not absorbed by the sandwiching members 130a and 130b, and thus the vibration of the detection plate 120 is suppressed. Can be further reduced.

  Next, a method for detecting adhesion of water droplets in the water droplet detection device 100 of the present embodiment will be described. In the water droplet detection device 100 of the present embodiment, a drive circuit 200 that drives the piezoelectric element 140 and a detection circuit 300 that detects a change in vibration of the detection plate 120 are housed in the circuit housing portion 111 of the case body 110.

  FIG. 3 is a circuit diagram showing a drive circuit 200 and a detection circuit 300 included in the water droplet detection device 100.

  In the present embodiment, the piezoelectric element 140 is driven by the drive circuit 200, and the detection plate 120 is vibrated in advance. Then, a change in vibration of the detection plate 120 when a water droplet touches the detection plate 120 is detected by the detection circuit 300 as a change in a voltage signal output from the piezoelectric element 140.

  A drive circuit 200 that supplies a drive signal for vibrating the piezoelectric element 140 and a detection circuit 300 that detects the vibration of the piezoelectric element 140 as a voltage signal are connected to the piezoelectric element 140.

  The drive circuit 200 of the present embodiment intermittently outputs a pulse signal at a predetermined interval to vibrate the piezoelectric element 140.

  The detection circuit 300 of this embodiment includes an amplifier 310, a filter 320, a rectifier circuit 330, an integration circuit 340, and a calculation unit 350. The input of the amplifier 310 is connected to the piezoelectric element 140 and detects and amplifies a voltage signal generated by the vibration of the piezoelectric element 140. The voltage signal amplified by the amplifier 310 is subjected to noise removal by the filter 320 and input to the rectifier circuit 330. The rectifier circuit 330 rectifies the voltage signal from which noise has been removed.

  The rectified voltage signal is input to the calculation unit 350 via the integration circuit 340. The arithmetic unit 350 detects a change in the voltage signal output from the piezoelectric element 140 based on the output of the integration circuit 340. The output signal of the calculation unit 350 may be supplied to, for example, a main body circuit that controls the main body of the apparatus having the water droplet detection apparatus 100 of the present embodiment.

  Hereinafter, the processing of the arithmetic unit 350 of the present embodiment will be described with reference to FIG. FIG. 4 is a block diagram illustrating the calculation unit 350.

  The arithmetic unit 350 includes an arithmetic processing device 351 and a storage device 352, and realizes the function of each unit described later. The arithmetic processing unit 351 of the present embodiment includes a waveform storage unit 353, a signal acquisition unit 354, and a waveform comparison unit 355.

  The waveform storage unit 353 of this embodiment acquires a waveform output from the integration circuit 340 when the piezoelectric element 140 is driven by the pulse signal supplied from the drive circuit 200, and the storage device 352 uses the acquired waveform as a reference waveform. Remember me. Therefore, the storage device 352 stores a waveform of vibration of the detection plate 120 in a state where a contact object such as a water droplet is not in contact with the detection plate 120 as a reference waveform. In the present embodiment, the reference waveform may be stored by the waveform storage unit 353 when power is supplied to the drive circuit 200 and the detection circuit 300 and the drive of the piezoelectric element 140 is started.

  The signal acquisition unit 354 periodically acquires a signal output from the integration circuit 340. The waveform comparison unit 355 compares the signal acquired by the signal acquisition unit 354 with the reference waveform stored in the storage device 352. If the two waveforms do not match as a result of the comparison, the waveform comparison unit 355 outputs a signal indicating that it has been detected that a non-contact object such as a water droplet has touched the detection plate 120.

  The operation of the calculation unit 350 of this embodiment will be described below with reference to FIG. FIG. 5 is a diagram illustrating a waveform detected by the calculation unit 350. FIG. 5A is a diagram illustrating a waveform in a state where no water droplet is attached to the detection plate 120, and FIG. 5B is a diagram illustrating a waveform in a state where spray is once sprayed on the detection plate 120. FIG. 5C is a diagram showing a waveform in a state where the detection plate 120 is sprayed twice by spraying.

  As shown in FIG. 5, in this embodiment, when water droplets adhere to the detection plate 120, the vibration of the detection plate 120 changes and appears as a change in the waveform of the voltage signal output from the piezoelectric element 140. Therefore, in this embodiment, if the waveform of the voltage signal in a state where no water droplet is attached to the detection plate 140 is stored as the reference waveform A, the waveform B of the voltage signal acquired later and the reference waveform A are compared. It is possible to detect whether water droplets on the detection plate 120 are attached.

  In the calculation unit 350 of this embodiment, for example, when the reference waveform A and the waveform B are different, the waveform B may be temporarily stored in the storage device 352. And the waveform comparison part 355 may compare the waveform B and the waveform C, for example, when the waveform C which changed further is acquired after the waveform B different from the reference | standard waveform A is acquired.

  In the present embodiment, if the calculation unit 350 is configured as described above, for example, a change in the amount of water droplets attached to the detection plate 120 can also be detected.

  For example, in the present embodiment, the storage device 352 may store in advance a table in which a waveform is associated with the amount of water droplets corresponding to the waveform. Then, when the signal output from the integration circuit 340 is acquired by the signal acquisition unit 354, the amount of water droplets attached to the detection plate 120 may be detected with reference to this table.

As described above, according to the present embodiment, the outer peripheral area of the detection plate 120 is partially fixed via the sandwiching members 130a and 130b, so that the vibration of the detection plate 120 is suppressed and the level of the output signal is reduced. Can be prevented from decreasing. Therefore, in this embodiment, an output signal can be acquired without suppressing vibration of the detection plate (vibration plate), and a minute change in vibration of the detection plate can be detected.
(Second embodiment)
A second embodiment of the present invention will be described below with reference to the drawings. The second embodiment of the present invention is different from the first embodiment in that the detection region is narrowed. Therefore, in the following description of the second embodiment, only differences from the first embodiment will be described, and those having the same functional configuration as the first embodiment will be used in the description of the first embodiment. The same reference numerals as those used are assigned, and the description thereof is omitted.

  FIG. 6 is a perspective view showing a water droplet detection device 100A of the second embodiment. The water droplet detection device 100A of the present embodiment includes a detection plate 120C in which the detection region 120B is exposed from the case body 110A.

  The case body 110A of the present embodiment includes a circuit storage portion 111A and a lid portion 112A. The circuit storage unit 111A stores a circuit for detecting water droplets. The lid portion 112A serves as a lid for the circuit storage portion 111A. Further, frame portions 113c and 113d surrounding the detection region 120B and cutout portions 114c and 114d for exposing the detection region 120B are formed in the circuit housing portion 111A and the lid portion 112A of the case body 110A of the present embodiment, respectively. . The frame portions 113c and 113d and the cutout portions 114c and 114d are formed so that the detection region 120B is exposed when the lid portion 112A is put on the circuit storage portion 111A.

  Next, a method for fixing the detection plate 120C in the water droplet detection device 100A of the present embodiment will be described with reference to FIG. FIG. 7 is a diagram illustrating a method for fixing the detection plate 120C. FIG. 7A is a top perspective view of the water droplet detection device 100A, and FIG. 7B is a cross-sectional view taken along line AA of the water droplet detection device 100A.

  In the present embodiment, the detection plate 120C is fixed to the case body 110A with the outer peripheral region partially sandwiched by the sandwiching members 130c and 130d. Therefore, also in this embodiment, it is possible to prevent the vibration of the detection plate 120C from being suppressed as in the first embodiment.

  In the present embodiment, the detection plate 120C includes the four clamping members 130c disposed between the detection plate 120C and the frame portion 113c, and the four clamping members disposed between the detection plate 120C and the frame portion 113d. Although it was set as the structure clamped by a total of eight clamping members with 130d, it is not limited to this. In the present embodiment, two sandwiching members 130c are disposed between the detection plate 120C and the frame portion 113c, and two sandwiching members 130d may be disposed between the detection plate 120C and the frame portion 113d. . In this case, the detection plate 120C is clamped by a total of four clamping members.

  The method for detecting a change in vibration of the detection plate 120C in the water droplet detection device 100A of the present embodiment is the same as that of the first embodiment.

  As mentioned above, although this invention has been demonstrated based on each embodiment, this invention is not limited to the requirements shown in the said embodiment. With respect to these points, the gist of the present invention can be changed without departing from the scope of the present invention, and can be appropriately determined according to the application form.

It is a perspective view which shows the water droplet detection apparatus 100 of 1st embodiment. It is a figure explaining the fixing method of the detection plate. 2 is a circuit diagram showing a drive circuit 200 and a detection circuit 300 included in the water droplet detection device 100. FIG. It is a block diagram explaining the calculating part 350. FIG. It is a figure which shows the waveform detected in the calculating part 350. FIG. It is a perspective view which shows 100A of water droplet detection apparatuses of 2nd embodiment. It is a figure explaining the fixing method of 120 C of detection plates.

Explanation of symbols

100, 100A Water drop detection circuit 110, 110A Case body 111, 111A Circuit storage part 112, 112A Cover part 113a, 113b, 113c, 113d Frame part 114a, 114b, 114c, 114d Cutout part 120, 120C Detection plate 120A, 120B Detection area 130a, 130b, 130c, 130d Holding member 140 Piezoelectric element 200 Drive circuit 300 Detection circuit 350 Calculation unit

Claims (4)

A detection device that includes a case body and a diaphragm, and detects contact of an object to be contacted with the diaphragm,
The diaphragm is
A detection device in which a part of an outer peripheral region of the diaphragm is fixed to the case body via a clamping member disposed between the diaphragm and the case body. A plurality of the clamping members are disposed between the outer peripheral region and the case body,
The detection device according to claim 1, wherein an outer peripheral region of the diaphragm is fixed to the case body via a plurality of the holding members arranged.   The detection device according to claim 1, wherein a material of the material forming the clamping member is harder than a material of the material forming the diaphragm. A piezoelectric element fixed to the diaphragm;
A detection circuit for detecting a change in a voltage signal output from the piezoelectric element;
The detection circuit includes:
Storage means for storing a waveform of a voltage signal when there is no contact of an object to be contacted with the diaphragm;
Obtaining means for obtaining a waveform of a voltage signal output from the piezoelectric element;
Comparing means for comparing the waveform stored in the storage means with the waveform of the voltage signal acquired by the acquiring means,
4. The detection device according to claim 1, wherein a contact of an object to be contacted with the diaphragm is detected based on a comparison result by the comparison unit. 5.

Images