JP2007255924A - Protective member for ultrasonic sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a protective member capable of protecting an ultrasonic sensor and transmitting and receiving ultrasonic waves efficiently.
SOLUTION: Since a transmission hole 32 is formed at a position where it cannot be seen from the reception hole 31 side, there is a possibility that foreign matter, water droplets, or the like may directly collide with an ultrasonic sensor 10 when flying toward a protective member 30. Therefore, the ultrasonic sensor 10 can be protected. Further, since the protection member 30 includes the communication path 33 formed so as to be able to transmit ultrasonic waves, the ultrasonic waves are directly transmitted and received by the ultrasonic sensor 10 via the communication path 33 without passing through other members. can do. Therefore, since attenuation of ultrasonic waves can be reduced, ultrasonic waves can be efficiently transmitted and received by the ultrasonic sensor 10.
[Selection] Figure 2

Description

  The present invention relates to a protective member for an ultrasonic sensor that transmits and receives ultrasonic waves.

In recent years, for example, an ultrasonic sensor mounted on an automobile (vehicle) has been known. This ultrasonic sensor transmits ultrasonic waves from the transmission means and receives the ultrasonic waves reflected by the object to be detected by the reception means, thereby measuring the direction in which the object around the automobile is located and the distance to the object. Perform measurements. In this way, development of technology that is useful for safe driving is being promoted by monitoring the surroundings of an automobile using an ultrasonic sensor.
For example, an ultrasonic sensor is mounted on the rear of an automobile, and a back sonar that receives and detects ultrasonic waves reflected by a person or an obstacle existing behind the automobile is detected by the ultrasonic sensor. An automatic parking support system that assists parking in the back while avoiding collision with the vehicle has been put into practical use.
Further, as a receiving element of the ultrasonic sensor, an ultrasonic sensor in which a vibrating portion made of a piezoelectric thin film is formed on a thin film portion formed as a thin portion of a substrate using MEMS (Micro Electro Mechanical System) technology. The receiving element is attracting attention.

Here, when the element of the ultrasonic sensor is mounted on the vehicle in a state of being exposed to the outside, if a water droplet or dust adheres to the surface of the element, the distance to the detected object cannot be measured accurately. Moreover, there is a risk of destruction due to an external force load such as a collision of pebbles.
Therefore, as an ultrasonic sensor provided with a protective structure for preventing element contamination and damage due to external force loading, for example, Patent Document 1 discloses that an element is mounted in an aluminum case so that the element is not exposed to the outside, An ultrasonic sensor has been disclosed in which a piezoelectric vibration detecting element for detecting the vibration is directly attached to a protective member that also serves as a diaphragm, and ultrasonic waves are received by vibration of the protective member.
JP 2002-58097 A

However, the ultrasonic sensor using the MEMS type element has a problem that the mechanical strength of the piezoelectric thin film is low due to its structure, and therefore it is easily damaged when directly attached to the protective member.
Also, in order to prevent breakage, if a space is provided between the piezoelectric thin film and the diaphragm without attaching the piezoelectric thin film to the diaphragm, there is a problem that ultrasonic waves cannot be transmitted and received efficiently. It was.

  Therefore, an object of the present invention is to realize a protective member that protects an ultrasonic sensor and can efficiently transmit and receive ultrasonic waves.

  In order to achieve the above object, according to the first aspect of the present invention, in the first aspect of the present invention, a protection member for protecting an ultrasonic sensor that includes a vibration unit capable of transmitting and receiving ultrasonic waves and detects a detection object by ultrasonic waves The first hole formed on the side where the object to be detected is formed and the position where the first hole is not visible from the side of the first hole and the position facing the vibration part. A technical means is used that includes a second hole, and a communication path that is formed to communicate the first hole and the second hole so as to transmit ultrasonic waves.

According to the first aspect of the present invention, since the second hole is formed at a position where the second hole cannot be seen from the first hole side, foreign matter such as pebbles or water droplets fly toward the protective member. Since there is no possibility of directly colliding with the ultrasonic sensor, the ultrasonic sensor can be protected.
In addition, since the protection member includes a communication path formed to transmit ultrasonic waves, the ultrasonic wave can be directly transmitted and received by the ultrasonic sensor via the communication path without passing through other members. . Therefore, since attenuation of ultrasonic waves can be reduced, ultrasonic waves can be efficiently transmitted and received by the ultrasonic sensor.

  The invention according to claim 2 uses the technical means that in the protection member of the ultrasonic sensor according to claim 1, the communication path is bent.

  According to the second aspect of the present invention, since the communication passage is bent, even when foreign matter such as pebbles or water droplets enter the communication passage, it collides with the inner wall of the communication passage. There is no possibility of directly colliding with the ultrasonic sensor, and the ultrasonic sensor can be protected.

  According to a third aspect of the present invention, in the protection member for an ultrasonic sensor according to the first or second aspect, the second hole is disposed at a position facing the central portion of the vibration part of the ultrasonic sensor. The technical means is used.

According to the third aspect of the invention, when transmitting ultrasonic waves from the ultrasonic sensor, ultrasonic waves with high sound pressure generated from the center of the vibrating part are transmitted from the second hole. The sound pressure of the ultrasonic wave transmitted from the ultrasonic sensor can be increased.
In addition, when ultrasonic waves are received by the ultrasonic sensor, since the ultrasonic waves are transmitted toward the central part of the vibration part, the displacement of the vibration part can be increased efficiently. Can be improved.

  According to a fourth aspect of the present invention, in the ultrasonic sensor protection member according to any one of the first to third aspects, the ultrasonic wave received by the ultrasonic sensor is formed on the wall surface of the communication path. The technical means that the inclined part inclined so that the said communication path becomes narrow with respect to the transmission direction is used.

  According to the fourth aspect of the present invention, at the time of receiving the ultrasonic wave, the ultrasonic wave is collected at the inclined portion inclined so that the communication path becomes narrower with respect to the transmission direction of the ultrasonic wave received by the ultrasonic sensor. Therefore, the sound pressure of the ultrasonic wave can be increased and the sensitivity of the ultrasonic sensor can be improved.

  According to a fifth aspect of the present invention, in the protection member for an ultrasonic sensor according to any one of the first to fourth aspects, the ultrasonic wave transmitted by the ultrasonic sensor to the wall surface of the communication path. The technical means that the inclined part inclined so that the said communication path becomes narrow with respect to the transmission direction is used.

  According to the fifth aspect of the present invention, the cross-sectional area of the communication path is increased to efficiently transmit the ultrasonic wave, and the communication path is narrowed with respect to the transmission direction of the ultrasonic wave transmitted by the ultrasonic sensor. The entrance of pebbles and dirt from the outside can be reduced in the inclined part.

  According to a sixth aspect of the present invention, in the ultrasonic sensor protective member according to any one of the first to fifth aspects, the first hole transmits the ultrasonic wave to the communication path. The technical means of being covered with a member is used.

  According to the sixth aspect of the invention, since the first hole is covered with the transmission member, it is possible to surely block the entry of liquids such as small foreign matters and rain, and thus the ultrasonic sensor can be protected more reliably. can do.

  According to a seventh aspect of the present invention, in the ultrasonic sensor protective member according to any one of the first to sixth aspects, the ultrasonic wave is reflected on the wall surface of the communication path to change the transmission direction. The technical means that the reflection part is formed is used.

  According to the seventh aspect of the present invention, since the transmission direction is changed by the reflection of the ultrasonic wave at the reflection part, the ultrasonic wave is reflected in the direction of the communication path as compared with the case where the reflection part is not formed. It is possible to reduce the attenuation of the ultrasonic wave due to unnecessary multiple reflections, and the sensitivity of the ultrasonic sensor can be improved.

  According to an eighth aspect of the present invention, in the protection member for an ultrasonic sensor according to any one of the first to seventh aspects, the communication path includes a resonance part that performs amplification by resonating the ultrasonic wave. The technical means of providing is used.

  According to the eighth aspect of the present invention, since the communication path includes a resonance unit that performs amplification by resonating ultrasonic waves, ultrasonic waves to be transmitted and received can be amplified in the communication path. The sensitivity of the acoustic wave sensor can be improved.

  According to a ninth aspect of the present invention, in the protection member for an ultrasonic sensor according to any one of the first to eighth aspects, the plurality of first holes opened in different directions, and the plurality of the first holes. Technical means comprising a plurality of the second holes corresponding to the first holes, a plurality of the communication passages communicating the first holes and the corresponding second holes. Is used.

  According to the ninth aspect of the invention, since the plurality of first holes opened in different directions are provided, the ultrasonic waves can be transmitted in various directions and reflected by the detection target. And since the ultrasonic wave propagating in various directions can be detected, the sensitivity of the ultrasonic sensor can be improved.

  According to a tenth aspect of the present invention, the ultrasonic sensor protective member according to any one of the first to eighth aspects further comprises a plurality of the first holes opened in different directions. The technical means that a plurality of said 1st holes and said 2nd hole are each connected by the said some communicating path is used.

  According to the invention described in claim 10, since the plurality of first holes opened in different directions are provided, the ultrasonic wave can be transmitted in various directions and reflected by the detection target. And since the ultrasonic wave propagating in various directions can be detected, the sensitivity of the ultrasonic sensor can be improved. Moreover, since the ultrasonic waves received in each first hole are collected in the second holes, the sound pressure of the ultrasonic waves can be increased, and the sensitivity of the ultrasonic sensor can be improved.

  According to an eleventh aspect of the present invention, in the protective member of the ultrasonic sensor according to any one of the first to eighth aspects, the protective member protects a plurality of the ultrasonic sensors, For the ultrasonic sensor, the technical means that the first hole, the second hole, and the communication path are provided, respectively.

  According to the invention described in claim 11, by obtaining the time difference and the phase difference of the ultrasonic waves received by the plurality of ultrasonic sensors, based on each difference, not only the distance to the detected object but also the object to be detected. The position of the detection object can also be measured. In addition, it is not necessary to prepare protective members for a plurality of ultrasonic sensors, and the protective members can be integrated into one protective member, so that the size of the protective members can be reduced and the aesthetics can be maintained. Can do.

  The invention described in claim 12 uses the technical means that in the ultrasonic sensor protective member according to claim 11, the first holes are arranged at intervals of the half wavelength of the ultrasonic wave. .

  According to the invention described in claim 12, since the first holes are arranged at intervals of the half wavelength of the ultrasonic wave, the time difference can be detected from the phase difference of the received ultrasonic wave. The time difference between the ultrasonic waves received by each ultrasonic sensor can be detected with high accuracy, and the measurement accuracy of the distance and position with respect to the detected object can be improved.

  According to a thirteenth aspect of the present invention, in the protection member for an ultrasonic sensor according to any one of the first to twelfth aspects, the first hole, the second hole, and the communication path are provided in an automobile. The technical means that the bumper is formed.

  According to the invention described in claim 13, since the first hole, the second hole and the communication path are formed in the bumper of the automobile, when the ultrasonic sensor is used as an obstacle sensor in front of the vehicle, Since the protective member is not exposed from the bumper, a vehicle with excellent design can be manufactured.

  According to a fourteenth aspect of the present invention, in the protection member for an ultrasonic sensor according to any one of the first to twelfth aspects, the first hole, the second hole, and the communication path are provided in an automobile. The technical means that it is formed on the headlamp cover of this is used.

  According to the fourteenth aspect of the present invention, since the first hole, the second hole, and the communication path are formed in the headlamp cover of the automobile, the ultrasonic sensor is used as an obstacle sensor in front of the vehicle. In addition, since the protective member is not exposed from the headlamp cover, a vehicle with excellent design can be manufactured.

<First Embodiment>
1st Embodiment of the protection member of the ultrasonic sensor which concerns on this invention is described with reference to figures. Here, a case where an ultrasonic sensor is mounted on a vehicle and used as an obstacle sensor will be described as an example. FIG. 1 is an explanatory diagram of an ultrasonic sensor. FIG. 1A is an explanatory plan view of an ultrasonic sensor, and FIG. 1B is an explanatory cross-sectional view taken along the line AA in FIG. FIG. 2 is an explanatory diagram of a protective member to which an ultrasonic sensor is attached. 2A is a plan explanatory view of the protection member of the ultrasonic sensor as viewed from the outside of the vehicle, and FIG. 2B is a cross-sectional explanatory view taken along the line BB in FIG. 2A. In FIG. 2B, the upper side in the figure indicates the outside of the vehicle. In addition, obstacles are described in order to explain the transmission of ultrasonic waves. FIG. 3 is a cross-sectional explanatory view of a protective member provided with an inclined portion that collects ultrasonic waves. FIG. 4 is a cross-sectional explanatory view of a protective member provided with a transmission member that covers the receiving hole. FIG. 5 is a cross-sectional explanatory view of a protective member provided with a reflecting portion that reflects ultrasonic waves. FIG. 6 is an explanatory cross-sectional view showing a modification example of the arrangement of the ultrasonic sensors. FIG. 7 is a cross-sectional explanatory view of a protective member provided with a receiving hole opened in different directions.
In each figure, a part is enlarged for explanation.

(Structure of ultrasonic sensor)
As shown in FIGS. 1A and 1B, the ultrasonic sensor 10 is formed using a rectangular semiconductor substrate 11 having an SOI (Silicon On Insulator) structure. The semiconductor substrate 11 is formed by laminating a first insulating film 11b, a silicon active layer 11c, and a second insulating film 11d in this order on an upper surface 11m of a support member 11a made of silicon.
At the central portion of the semiconductor substrate 11, the central portions of the support member 11a and the first insulating film 11b are removed in a square shape by MEMS technology. As a result, the support member 11a is formed in a flat plate shape having a hollowed center portion, and the remaining silicon active layer 11c and the second insulating film 11d are formed in a rectangular thin film shape.

A piezoelectric vibration detecting element 12 is formed on the second insulating film 11d so as to cover a portion formed in a thin film shape. The piezoelectric vibration detecting element 12 is formed, for example, by sandwiching a piezoelectric thin film 12 a made of lead zirconate titanate (PZT) between a lower surface electrode 13 and an upper surface electrode 14.
Thereby, the vibration part 15 whose end part is lifted by the support member 11a is formed. The vibration unit 15 has a predetermined resonance frequency, receives the ultrasonic wave reflected by the detection object and transmitted to the ultrasonic sensor 10, and resonates. The displacement of the vibration part 15 caused by this resonance is converted into a voltage signal by the piezoelectric vibration detection element 12, and an ultrasonic wave is detected.
As described above, the ultrasonic sensor 10 manufactured using the MEMS technology is suitable as a receiving element because of its high ultrasonic wave receiving sensitivity.

(Structure of protective member of ultrasonic sensor)
As shown in FIGS. 2A and 2B, the protection member 30 for protecting the ultrasonic sensor 10 from contamination or the like by collision of foreign matter or wind and rain is formed in a rectangular flat plate shape, and is a vehicle bumper. A surface 52a is attached to a mounting portion 52a that is formed so as to penetrate through the surface 52a.
Since the protective member 30 is exposed to the outside air, it is necessary to form the protective member 30 using a material having high weather resistance and robustness. Therefore, as the material constituting the protection member 30, various metal materials such as stainless steel and aluminum alloy are preferable. Various synthetic resins, glass, ceramics, rubber and the like can also be used.

  A transmission hole 32 for transmitting ultrasonic waves generated in the vibration part 15 of the ultrasonic sensor 10 is formed in the center of the back surface 30b of the protection member 30. A reception hole 31 for receiving the ultrasonic wave reflected by the obstacle M, which is a detection object, is formed in the surface 30a of the protection member 30. The reception hole 31 and the transmission hole 32 communicate with each other through a communication path 33 that can transmit ultrasonic waves.

  The ultrasonic sensor 10 is attached to the back surface 30b of the protection member 30 on the bottom surface of the support member 11a. Here, the transmission hole 32 is formed to be smaller than the vibration part 15, and the ultrasonic sensor 10 is attached at a position where the perpendicular H drawn from the center part of the vibration part 15 passes through the transmission hole 32. That is, the ultrasonic sensor 10 is attached at a position where the transmission hole 32 faces the central portion of the vibration unit 15.

  A circuit element 21 that detects a voltage signal output from the piezoelectric vibration detection element 12 (FIG. 2) is electrically connected to the ultrasonic sensor 10 via bumps 20. The circuit element 21 is electrically connected to the ECU via a wiring (not shown).

Here, the reception hole 31 is formed at a position shifted in the width direction of the protection member 30 with respect to the transmission hole 32. The communication path 33 extends from the reception hole 31 and the transmission hole 32 in the thickness direction of the protective member 30 and is bent at a substantially right angle in the width direction, and is connected to a resonance part 33b in which transmitted and received ultrasonic waves resonate. ing.
That is, when the reception hole 31 is viewed from the surface 30a side, the transmission hole 32 cannot be visually recognized.
As a result, for example, when foreign matter such as pebbles or water droplets fly toward the protection member 30 and enter the inside of the protection member 30 from the reception hole 31, it directly collides with the vibration unit 15 of the ultrasonic sensor 10. Therefore, the ultrasonic sensor 10 can be protected.
Here, since the resonance part 33b is formed so that the length in the longitudinal direction is an integral multiple of a half wavelength of the ultrasonic wave, the ultrasonic wave to be transmitted and received resonates and is amplified.

The protective member 30 is not limited to a rectangular flat plate shape, and may be, for example, a disk shape, and the surface 30a may be a curved surface instead of a flat surface.
The communication path 33 is not limited to a shape bent at a substantially right angle, and may be formed in an S shape, for example.
The ultrasonic sensor 10 may be dedicated to reception or transmission.

(Ultrasonic transmission)
As shown in FIG. 2B, the ultrasonic wave generated in the ultrasonic sensor 10 is transmitted to the inside of the protective member 30 from the transmission hole 32 of the protective member 30 and proceeds in the thickness direction. The ultrasonic wave that has traveled in the thickness direction of the protection member 30 travels in the communication path 33 while changing its transmission direction in the width direction, and is amplified in the resonance portion 33b. Then, the transmission direction is further changed to advance from the receiving hole 31 toward the outside of the protection member 30.
The ultrasonic wave reflected by the obstacle M, which is the detection object, is transmitted from the reception hole 31 of the protection member 30 to the inside of the protection member 30 and travels in the thickness direction. Thereafter, the ultrasonic wave follows the path opposite to the transmitted ultrasonic wave, is amplified by the resonance unit 33b, and then reaches the vibration unit 15 of the ultrasonic sensor 10 to vibrate the vibration unit 15.

  Then, when the vibration unit 15 vibrates, a voltage signal is output from the piezoelectric vibration detection element 12 (FIG. 1) to the circuit element 21. The circuit element 21 performs arithmetic processing based on the voltage signal output from the piezoelectric vibration detecting element 12, for example, amplifies the signal and removes noise, or compares the ultrasonic waves transmitted and received by the ultrasonic sensor 10. Then, by measuring the time difference and phase difference, distance measurement with the detection object is performed.

  Thereby, since the ultrasonic wave is directly transmitted between the obstacle M and the ultrasonic sensor 10 via the communication path 33 without passing through other members, the attenuation of the ultrasonic wave can be reduced. . In addition, since the transmission hole 32 is provided at a position facing the vibration unit 15, when transmitting an ultrasonic wave from the ultrasonic sensor 10, an ultrasonic wave having a high sound pressure generated from the central portion of the vibration unit 15. Therefore, the sound pressure of the ultrasonic wave transmitted from the ultrasonic sensor 10 can be increased. Further, when ultrasonic waves are received by the ultrasonic sensor 10, since the ultrasonic waves are transmitted toward the central portion of the vibration unit 15, the displacement of the vibration unit 15 can be increased, and thus the ultrasonic sensor 10. The sensitivity can be improved.

  Here, since the sound pressure of the ultrasonic wave is proportional to the cross-sectional area of the transmission path, the area of the receiving hole 31 and the transmitting hole 32 is set to the area of the vibrating part 15 in order to transmit and receive an ultrasonic wave with sufficient signal strength. It is preferable to set it to 1/10 or more.

(Modification 1)
As shown in FIG. 3, an inclined portion 30 c that is inclined so that the communication path 33 becomes narrow may be formed on the wall surface of the communication path 33. As shown in FIG. 3A, when the inclined portion 30c is formed so that the communication path 33 becomes narrower with respect to the transmission direction of the ultrasonic wave received by the ultrasonic sensor 10, it is reflected by the obstacle M. Since ultrasonic waves can be collected, the reception sensitivity of the ultrasonic sensor 10 can be improved.
As shown in FIG. 3B, when the inclined portion 30c is formed so that the communication path 33 becomes narrower with respect to the transmission direction of the ultrasonic wave transmitted by the ultrasonic sensor 10, the communication path 33 The cross-sectional area is increased to efficiently transmit ultrasonic waves, and pebbles and dirt from the outside in the inclined portion 30c inclined so that the communication path 33 becomes narrower with respect to the transmission direction of the ultrasonic waves transmitted by the ultrasonic sensor 10. Can be reduced.

(Modification 2)
As shown in FIG. 4, the transmission member 34 may be formed by covering the reception hole 31 with a material capable of transmitting ultrasonic waves to the communication path 33, for example, a resin film having a thickness of about 1 mm.
When this configuration is used, since the receiving hole 31 is covered with the transmission member 34, there is no possibility that small foreign matter or liquid such as rain may enter the communication path 33, so that the ultrasonic sensor 10 can be protected more reliably. Can do. The transmission member 34 may be a material other than a resin film as long as it has a material and dimensions that do not significantly attenuate ultrasonic waves. For example, a metal foil or the like can be used.

(Modification 3)
A reflection portion 33 a that reflects ultrasonic waves may be formed on the wall surface of the bent portion of the communication path 33. As shown in FIG. 5A, the reflecting portion 33 a is formed as a surface inclined by 45 ° with respect to the thickness direction of the protective member 30. When this configuration is used, the ultrasonic wave transmitted from the receiving hole 31 to the inside of the protection member 30 is reflected by the reflecting portion 33a near the receiving hole 31 to change the transmission direction to the longitudinal direction of the communication path 33. The light is reflected at the reflecting portion 33 a close to the transmission hole 32 and travels toward the vibrating portion 15. In this way, since the ultrasonic waves are transmitted by changing the transmission direction by being reflected, the ultrasonic waves can be reflected in the direction of the communication path as compared with the case where the reflection portion 33a is not formed. It is possible to reduce the attenuation of ultrasonic waves due to unnecessary multiple reflections, to reduce the attenuation of ultrasonic waves due to interference, etc., and to improve the sensitivity of the ultrasonic sensor 10. it can.
Further, as shown in FIG. 5B, for example, when the reflecting member 33 is plated to form the reflective material 35, the reflection efficiency of the ultrasonic wave is improved, so that the sensitivity of the ultrasonic sensor 10 is further improved. be able to.
Here, if the reflection part 33a can change the transmission direction of an ultrasonic wave along the longitudinal direction of the communicating path 33, the inclination | tilt angle can be set freely and it forms in a curved surface not only in a plane. Also good.

(Modification 4)
The ultrasonic sensor 10 may not be directly attached to the protection member 30. As shown in FIG. 6A, the vibration part 15 may be attached to another attachment member 60 in a state where the vibration part 15 faces the transmission hole 32. In addition, as shown in FIG. 6B, the surface opposite to the support member 11 a of the ultrasonic sensor 10 may be opposed to the vibration unit 15.
If this structure is used, the freedom degree of the design which arrange | positions the ultrasonic sensor 10 can be increased.

(Modification 5)
A plurality of receiving holes 31 opened in different directions in the protection member 30 may be formed. For example, as shown in FIG. 7A, a plurality of reception holes 31 that open in different directions, a plurality of transmission holes 32 corresponding to the plurality of reception holes 31, and each reception hole 31 correspond to each other. You may use the structure provided with the some communication path 33 which connects each transmission hole 32. FIG.
When this configuration is used, ultrasonic waves can be transmitted in various directions, and ultrasonic waves reflected on the obstacle M and propagated in various directions can be detected. Can be improved.
Further, as shown in FIG. 7B, a plurality of reception holes 31 opened in different directions are provided, and the plurality of reception holes 31 and the transmission holes 32 are respectively communicated by a plurality of communication paths 33. The configuration may be used.
When this configuration is used, ultrasonic waves can be transmitted in various directions, and ultrasonic waves reflected on the obstacle M and propagated in various directions can be detected. Can be improved. In addition, since the ultrasonic waves received at the respective reception holes 31 are collected at the transmission holes 32, the sound pressure of the ultrasonic waves can be increased, and the sensitivity of the ultrasonic sensor 10 can be improved.

(Modification 6)
It is also possible to use a configuration in which the reception hole 31, the transmission hole 32, and the communication path 33 are formed in a resin or metal bumper 52 and used as the protection member 30 and the ultrasonic sensor 10 is directly attached to the bumper 52. . In addition, it is possible to use a configuration in which the reception hole 31, the transmission hole 32, and the communication path 33 are formed in the headlamp cover and used as the protection member 30, and the ultrasonic sensor 10 is directly attached to the headlamp cover.
When these configurations are used, when the ultrasonic sensor 10 is used as an obstacle sensor in front of the vehicle, the protective member 30 is not exposed from the bumper 52 or the headlamp cover, so that a vehicle with excellent design is manufactured. be able to.
Other members can be used as the protective member 30 in accordance with the application of the ultrasonic sensor 10. For example, when the ultrasonic sensor 10 is used as an obstacle sensor on the side of the vehicle, the ultrasonic sensor 10 can be attached using a winker cover or the like as the protective member 30. In addition, the ultrasonic sensor 10 can be attached using the rear lamp cover, the back lamp cover, or the body as the protective member 30.

<Effects of First Embodiment>
(1) Since the transmission hole 32 is formed at a position where it cannot be seen from the reception hole 31 side, foreign matter such as pebbles, water droplets, and the like directly collide with the ultrasonic sensor 10 when flying toward the protection member 30. Since there is no fear, the ultrasonic sensor 10 can be protected. Further, since the communication path 33 is formed to be bent, even if foreign matter or water droplets enter the communication path 33, the communication path 33 may collide with the inner wall of the communication path 33 and directly collide with the ultrasonic sensor 10. Therefore, the ultrasonic sensor 10 can be protected.
Further, since the protection member 30 includes the communication path 33 formed so as to be able to transmit ultrasonic waves, the communication path 33 is interposed between the obstacle M and the ultrasonic sensor 10 without passing through other members. Can be directly transmitted and received by the ultrasonic sensor 10. Therefore, since attenuation of ultrasonic waves can be reduced, ultrasonic waves can be efficiently transmitted and received by the ultrasonic sensor 10.

(2) When transmitting an ultrasonic wave from the ultrasonic sensor 10, an ultrasonic wave having a high sound pressure generated from the central portion of the vibration unit 15 is transmitted from the transmission hole 32, and thus transmitted from the ultrasonic sensor 10. The sound pressure of ultrasonic waves can be increased. Further, when ultrasonic waves are received by the ultrasonic sensor 10, since the ultrasonic waves are transmitted toward the central part of the vibration part 15, the displacement of the vibration part 15 can be increased efficiently, so that the ultrasonic wave The sensitivity of the sensor 10 can be improved.

(3) Since the communication path 33 includes the resonance unit 33b that performs amplification by resonating the ultrasonic waves, the ultrasonic waves to be transmitted and received can be amplified in the communication path. Can be improved.

Second Embodiment
2nd Embodiment of the protection member of the ultrasonic sensor which concerns on this invention is described with reference to figures. FIG. 8 is a cross-sectional explanatory view of a protection member of an ultrasonic sensor to which a plurality of ultrasonic sensors are attached. 8A is an explanatory plan view of the protection member of the ultrasonic sensor as viewed from the outside of the vehicle, and FIG. 8B is a cross-sectional view taken along the line CC in FIG. 8A.
In addition, about the structure similar to 1st Embodiment, while using the same code | symbol, description is abbreviate | omitted.

(Structure of protective member of ultrasonic sensor)
As shown in FIG. 8A, a total of four ultrasonic sensors 10 are arranged in an array on the protective member 30 of this embodiment, two in the vertical and horizontal directions.
As shown in FIG. 8B, the transmission holes 32 are respectively arranged at positions facing the vibrating portions 15 of the ultrasonic sensors 10, and the reception holes 31 are in the area surrounded by the four ultrasonic sensors 10. The distance L between the reception holes 31 adjacent to each other around the center is arranged to be equal to the half wavelength of the ultrasonic wave.

When a plurality of ultrasonic sensors 10 are used in this way, the time difference and phase difference of the ultrasonic waves received by each ultrasonic sensor 10 are obtained, and based on each difference, not only the distance to the detected object but also the detected object. The position of the detection object can also be measured. Moreover, since it is not necessary to prepare the protective member 30 for each of the plurality of ultrasonic sensors 10 and can be integrated into one protective member 30, the size of the protective member 30 can be reduced. You can keep the beauty.
Here, as in the present embodiment, when the interval L between the central portions of the reception holes 31 adjacent to each other is set equal to the half wavelength of the ultrasonic wave, the time difference is also obtained from the phase difference of the received ultrasonic wave. Since it can detect, the time difference of the ultrasonic wave received by each ultrasonic sensor 10 can be detected with high accuracy, and the measurement accuracy of the distance and the position with the obstacle M can be improved.
The number of receiving elements is an example, and is not limited to four. Also, the arrangement is not limited to two vertically and horizontally. A chip in which a plurality of ultrasonic sensors 10 are integrally formed may be used.

  Here, when the distances from the receiving hole 31 of the protection member 30 to the vibrating portion 15 of the ultrasonic sensor 10 are equal, the ultrasonic waves that have traveled from the receiving hole 31 to the inside of the protecting member 30 are transmitted to the vibrating portion 15. Since the transmission time until transmission is equalized in each ultrasonic sensor 10, when measuring the position of the obstacle M, the measurement accuracy of the time difference of the ultrasonic waves transmitted from each reception hole 31 is improved. Therefore, the measurement accuracy of the position of the obstacle M can be improved.

<Effects of Second Embodiment>
(1) By obtaining the time difference and phase difference of the ultrasonic waves received by each ultrasonic sensor 10, not only the distance to the detected object but also the position of the detected object can be measured based on each difference. it can. Moreover, since it is not necessary to prepare the protective member 30 for each of the plurality of ultrasonic sensors 10 and can be integrated into one protective member 30, the size of the protective member 30 can be reduced. You can keep the beauty.

(2) If the distance L between the central portions of the receiving holes 31 adjacent to each other is set equal to the half wavelength of the ultrasonic wave, the time difference can be detected from the phase difference of the received ultrasonic waves. The time difference of the ultrasonic waves received by each ultrasonic sensor 10 can be detected with high accuracy, and the measurement accuracy of the distance and position with the obstacle M can be improved.

<Other embodiments>
(1) The communication path 33 may be formed along the side surface of the ultrasonic sensor 10. As shown in FIG. 9A, a part of the protection member 30 is formed thick, and the communication path 33 is formed in the thickness direction in a region in contact with the side surface of the ultrasonic sensor 10. The transmission hole 32 has an opening formed in a portion where the bump 20 is not formed, and the ultrasonic wave is transmitted to the vibration unit 15 from the surface opposite to the support member 11a. Further, as shown in FIG. 9B, a cutout is formed in a part of the support member 11a, a transmission hole 32 is formed adjacent to the cutout portion, and ultrasonic waves are transmitted to the vibration unit 15. It is also possible to use a configuration that does this.

(2) Although the piezoelectric vibration detection element 12 is used as the vibration unit 15 of the ultrasonic sensor 10, the present invention is not limited to this, and a capacitive vibration detection element that detects ultrasonic waves by a change in capacitance between electrodes. Etc. can also be used.

[Correspondence between each claim and embodiment]
The reception hole 31 corresponds to the first hole, the transmission hole 32 corresponds to the second hole, and the obstacle M corresponds to the detected object.

It is explanatory drawing of an ultrasonic sensor. FIG. 1A is an explanatory plan view of an ultrasonic sensor, and FIG. 1B is an explanatory cross-sectional view taken along the line AA in FIG. It is explanatory drawing of the protection member to which the ultrasonic sensor was attached. 2A is a plan explanatory view of the protection member of the ultrasonic sensor as viewed from the outside of the vehicle, and FIG. 2B is a cross-sectional explanatory view taken along the line BB in FIG. 2A. It is sectional explanatory drawing of the protection member provided with the inclination part which collects an ultrasonic wave. It is sectional explanatory drawing of the protection member which provided the transmission member which covers a receiving hole. It is sectional explanatory drawing of the protection member provided with the reflection part which reflects an ultrasonic wave. It is sectional explanatory drawing which shows the example of a change of arrangement | positioning of an ultrasonic sensor. It is sectional explanatory drawing of the protection member provided with the receiving hole opened toward a different direction. It is a section explanatory view of a protection member of an ultrasonic sensor in which a plurality of ultrasonic sensors were attached. 8A is an explanatory plan view of the protection member of the ultrasonic sensor as viewed from the outside of the vehicle, and FIG. 8B is a cross-sectional view taken along the line CC in FIG. 9A and 9B are cross-sectional explanatory views of a protection member according to another embodiment.

Explanation of symbols

10 Ultrasonic sensor
DESCRIPTION OF SYMBOLS 15 Vibration part 30 Protection member 30a Front surface 30b Back surface 30c Inclination part 31 Reception hole (1st hole)
32 Transmission hole (second hole)
33 Communication path 33a Reflector 34 Transmission member 35 Reflector
52 Bumper M Obstacle

Claims (11)

A protection member for protecting an ultrasonic sensor that includes a vibration unit capable of transmitting and receiving ultrasonic waves and detects a detection object by ultrasonic waves,
A first hole having an opening formed on the side where the detected object exists;
A second hole formed at an invisible position from the first hole side and facing the vibrating portion;
A communication path formed to communicate the first hole and the second hole and transmit ultrasonic waves;
A protective member for an ultrasonic sensor, comprising:   The protection member of an ultrasonic sensor according to claim 1, wherein the communication path is bent.   The ultrasonic sensor protection member according to claim 1, wherein the second hole is disposed at a position facing a central portion of a vibration part of the ultrasonic sensor.   2. The inclined portion is formed on the wall surface of the communication path so that the communication path becomes narrower with respect to a transmission direction of ultrasonic waves received by the ultrasonic sensor. The protection member of the ultrasonic sensor according to claim 3.   2. The inclined portion is formed on the wall surface of the communication path so that the communication path is narrower with respect to a transmission direction of the ultrasonic wave transmitted by the ultrasonic sensor. The protection member of the ultrasonic sensor according to claim 4.   The ultrasonic sensor protective member according to claim 1, wherein the first hole is covered with a transmission member capable of transmitting ultrasonic waves to the communication path. .   The ultrasonic sensor according to any one of claims 1 to 6, wherein a reflection portion that reflects ultrasonic waves and changes a transmission direction is formed on a wall surface of the communication path. Element.   The plurality of first holes opened in different directions, the plurality of second holes corresponding to the plurality of first holes, each first hole, and each corresponding second hole The ultrasonic sensor protective member according to claim 1, further comprising a plurality of the communication passages communicating with each other.   A plurality of the first holes opened in different directions are provided, and the plurality of the first holes and the second hole are respectively communicated by the plurality of communication paths. The protection member for an ultrasonic sensor according to any one of claims 1 to 7. A protective member for protecting a plurality of the ultrasonic sensors,
The said 1st hole, the said 2nd hole, and the said communicating path are each provided with respect to each said ultrasonic sensor, Each of Claim 1 thru | or 7 characterized by the above-mentioned. Ultrasonic sensor protective member.   11. The protection member for an ultrasonic sensor according to claim 10, wherein each of the first holes is disposed at an interval of a half wavelength of the ultrasonic wave.

Images