Attachment for ultrasonic transducer

Abstract

Provided is an attachment for an ultrasonic transducer which can be used by being changed to a different directional characteristic in accordance with the situation, even if there is only one ultrasonic transducer. An attachment 60 of the present invention, which is attached to an ultrasonic transducer 10, comprises an acoustic lens 81, a holding member 61, and a horizontal maintaining means 71. The acoustic lens 81 has a planar surface 82 and a convex surface 83 positioned on the opposite side to the planar surface 82. The holding member 61 holds the acoustic lens 81 with the planar surface 82 facing upward, and detachably holds the ultrasonic transducer 10 such that an acoustic emission surface 10a is acoustically connected to the planar surface 82. The horizontal maintaining means 71 maintains the ultrasonic transducer 10 and the acoustic lens 81 in a horizontal state.

Description

[Technical Field]

[0001] The present invention relates to an attachment that is attached to an ultrasonic transducer. [Background technology]

[0002] Conventionally, there has been known an ultrasonic transmitter / receiver that contains an ultrasonic vibrator and is suspended by a signal transmission cable and immersed in water, and that performs fish detection by transmitting and receiving ultrasonic waves using the ultrasonic vibrator. This ultrasonic transmitter / receiver is used, for example, in ice fishing such as smelt fishing. In ice fishing, the ultrasonic transmitter / receiver is inserted into the water through a hole drilled in the ice.

[0003] However, there is a demand for adjusting (changing) the directional characteristics of ultrasonic waves emitted from an ultrasonic transducer. Conventionally, it has been proposed to use an acoustic lens having a convex or concave surface as a member for changing the directional characteristics of ultrasonic waves (see, for example, Patent Documents 1 to 5). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 59-85972 (Figs. 2, 5, 6, etc.) [Patent Document 2] JP 5-212355 A (Claim 2, paragraphs

[0012] and

[0023] , Figures 1 and 2, etc.) [Patent Document 3] JP-A-10-179582 (paragraph

[0017] , Figure 1, etc.) [Patent Document 4] JP 2001-169393 A (claims 1, 3, 4, paragraphs

[0010] and

[0016] , figures 1 and 4, etc.) [Patent Document 5] JP-A-9-298795 (Claim 3, paragraphs

[0035] and

[0037] , Figures 6 to 8, etc.) DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0005] However, in the conventional techniques described in Patent Documents 1 to 5, the acoustic lens is directly attached to the ultrasonic transducer, which causes a problem in that the directional characteristics of the ultrasonic waves cannot be changed to different directional characteristics even if the situation changes.

[0006] Furthermore, to improve the detection accuracy of an ultrasonic transmitter / receiver, it is preferable to keep the acoustic emitting surface of the ultrasonic transmitter / receiver horizontal and radiate (transmit) ultrasonic waves vertically downward. Conventionally, the acoustic emitting surface is kept horizontal by the weight of the ultrasonic transmitter / receiver. However, if the ultrasonic transmitter / receiver is tilted, the acoustic emitting surface also tilts, causing the direction of the radiated ultrasonic waves to tilt relative to the vertical. In this case, fish schools cannot be detected accurately, resulting in errors in the display on the fish finder.

[0007] The present invention has been made in view of the above problems, and its first object is to provide an attachment for an ultrasonic transmitter / receiver that can change the directional characteristics depending on the situation even when there is only one ultrasonic transmitter / receiver, and its second object is to provide an attachment for an ultrasonic transmitter / receiver that can transmit ultrasonic waves vertically downward by maintaining the ultrasonic transmitter / receiver horizontally, thereby improving detection accuracy. [Means for solving the problem]

[0008] In order to solve the above problem, the invention described in claim 1 is an attachment to be attached to an ultrasonic transmitter / receiver for a fish finder, which is suspended from a cable, contains an ultrasonic vibrator that transmits and receives ultrasonic waves in a molded state, and has a bottom surface that serves as an acoustic radiation surface, and is characterized by comprising: an acoustic lens having a flat surface and a convex surface located on the opposite side; a holding member that holds the acoustic lens with the flat surface facing up and detachably holds the ultrasonic transmitter / receiver so that the acoustic radiation surface is acoustically connected to the flat surface of the acoustic lens; and a horizontal maintenance means that maintains the ultrasonic transmitter / receiver and the acoustic lens horizontal.

[0009] According to the invention of claim 1, an ultrasonic transmitter / receiver is detachably held by a holding member, and an acoustic lens is disposed on the acoustic emitting surface side of the ultrasonic transmitter / receiver held by the holding member. Therefore, even with only one ultrasonic transmitter / receiver, the directional characteristics of the ultrasonic waves emitted from the acoustic emitting surface can be changed depending on the situation. Specifically, by holding the ultrasonic transmitter / receiver on the holding member, the directional characteristics of the ultrasonic waves can be changed using the acoustic lens. On the other hand, by removing the ultrasonic transmitter / receiver from the holding member, the directional characteristics of the ultrasonic waves can be restored to their original directional characteristics. Furthermore, since the horizontality maintaining means maintains the ultrasonic transmitter / receiver and the acoustic lens horizontally, the acoustic emitting surface of the ultrasonic transmitter / receiver and the flat surface of the acoustic lens are also horizontal. As a result, ultrasonic waves can be transmitted vertically downward, improving the detection accuracy of the ultrasonic transmitter / receiver. The convex surface of the acoustic lens can be a spherical surface, a conical surface, or the like.

[0010] The invention described in claim 2 is characterized in that, in claim 1, the horizontal maintenance means is a horizontal maintenance device that is installed at the opening of a hole in the ice and maintains the ultrasonic transmitter / receiver and the acoustic lens horizontal.

[0011] Therefore, according to the invention described in claim 2, the ultrasonic transmitter / receiver and acoustic lens held by the holding member can be easily maintained in a horizontal position simply by placing the leveling device at the opening of the hole in the ice. Furthermore, because the leveling device is supported by the solid ice, the ultrasonic transmitter / receiver and acoustic lens can be stably maintained in a horizontal position.

[0012] The invention described in claim 3 is based on claim 2, and its gist is that the level maintenance device comprises a frame body having multiple sides, a rod-shaped member connecting the level maintenance device and the holding member is positioned at a position offset from the center of the frame body, and the holding member is positioned inside the frame body.

[0013] Therefore, according to the invention described in claim 3, since the leveling device is made of a frame body with multiple sides, it can be more stably installed in the opening of the hole in the ice than when the leveling device has, for example, a single side. Furthermore, since the rod-shaped member connecting the leveling device to the holding member is positioned off-center, the rod-shaped member does not get in the way when attaching or detaching the ultrasonic transmitter / receiver to the holding member. Furthermore, since the holding member is positioned inside the frame body, the ultrasonic transmitter / receiver inserted from inside the frame body can be easily held by the holding member. It is preferable that the diagonal length of the frame body be longer than the inner diameter of the hole in the ice. This prevents the leveling device from falling into the hole.

[0014] The invention described in claim 4 is based on claim 2 or 3, and is characterized in that the level-maintaining device is made of a frame body having an even number of sides of four or more, and is foldable.

[0015] Therefore, according to the invention as set forth in claim 4, the level maintaining device (frame) can be folded compactly, making it easy to carry the level maintaining device.

[0016] The invention described in claim 5 is characterized in that, in claim 1, the horizontal maintenance means is a buoyant body that is arranged to surround the holding member from the outer periphery, is made of a material with a specific gravity lower than that of water, and maintains the ultrasonic transmitter / receiver and the acoustic lens horizontal by the buoyancy acting on it.

[0017] Therefore, according to the invention of claim 5, the horizontality maintaining means is a buoyant body provided so as to surround the outer periphery of the holding member, so that buoyancy acts evenly on the holding member, making it easier to eliminate tilt of the holding member. As a result, the posture of the ultrasonic transmitter / receiver and acoustic lens held by the holding member in water can be easily stabilized, and the acoustic emitting surface of the ultrasonic transmitter / receiver and the flat surface of the acoustic lens can be reliably kept horizontal, making it easy to improve the detection accuracy of the ultrasonic transmitter / receiver.

[0018] The invention described in claim 6 is characterized in that, in any one of claims 1 to 5, the acoustic lens is detachably held on the holding member and is selected from a plurality of types of acoustic lenses that differ from each other in at least one of dimensions and shapes.

[0019] Therefore, according to the invention described in claim 6, even if there is only one ultrasonic transmitter / receiver, by holding an acoustic lens selected from multiple types of acoustic lenses in the holding member depending on the situation, the directional characteristics of the ultrasonic waves can be switched to various directional characteristics and used.

[0020] The invention described in claim 7 is characterized in that, in any one of claims 1 to 6, an insertion hole is provided in the bottom of the holding member into which the convex side of the acoustic lens, with the flat side facing up, is inserted so that the insertion hole protrudes downward from the bottom surface of the holding member, and the insertion hole has a shape in which the inner diameter gradually increases as it goes upward.

[0021] Therefore, according to the invention described in claim 7, the acoustic lens is held by the holding member with a portion of the convex surface in surface contact with the inner surface of the fitting hole, making it easier to insert the ultrasonic transmitter / receiver into the fitting hole.

[0022] The invention described in claim 8 is based on any one of claims 1 to 6, and is characterized in that the bottom of the holding member is provided with an insertion hole into which the convex side of the acoustic lens, with the flat side facing up, is inserted so that it protrudes downward from the bottom surface of the holding member, and a mounting fixture is provided that is fixed to the inner peripheral side of the holding member and presses down the flat side of the acoustic lens inserted into the insertion hole.

[0023] Therefore, according to the invention described in claim 8, the acoustic lens is fixed in a state sandwiched between the bottom of the holding member and the mounting fixture, so the acoustic lens can be reliably fixed and held in place, eliminating the problem of the acoustic lens sticking to the ultrasonic transmitter / receiver and falling into the water when the ultrasonic transmitter / receiver is lifted.

[0024] The invention described in claim 9 is based on any one of claims 1 to 6, and is characterized in that the bottom of the holding member is provided with an insertion hole for inserting the convex side of the acoustic lens with the flat side facing up so that it protrudes downward from the bottom surface of the holding member, and a water supply / drain hole for supplying water into the holding member and discharging the water from within the holding member, the water supply / drain hole being formed by widening a portion of the insertion hole, and the acoustic emitting surface of the ultrasonic transmitter / receiver and the flat surface of the acoustic lens are acoustically coupled via water.

[0025] Therefore, according to the invention described in claim 9, when the attachment attached to the ultrasonic transmitter / receiver is immersed in water, water is supplied into the holding member through the water inlet / outlet hole and penetrates between the acoustic emission surface of the ultrasonic transmitter / receiver and the flat surface of the acoustic lens. As a result, the ultrasonic transmitter / receiver and the acoustic lens can be used in close contact with each other via water, which acts as a coupling material, making it possible to achieve a wider directional characteristic of the ultrasonic waves than the original directional characteristic. Furthermore, when the attachment is removed from the water, water can be smoothly discharged toward the holding member through the water inlet / outlet hole.

[0026] The invention described in claim 10 is characterized in that, in any one of claims 1 to 9, a groove portion extending circumferentially of the ultrasonic transmitter / receiver is formed on the outer surface of the ultrasonic transmitter / receiver, and a fastening member passing through the retaining member is fitted into the groove portion.

[0027] Therefore, according to the invention described in claim 10, by fitting a fastening member into the groove portion, it is possible to prevent the ultrasonic transmitter / receiver and the acoustic lens located below it from coming loose, thereby ensuring that the ultrasonic transmitter / receiver and the acoustic lens are securely fixed in place. [Effects of the Invention]

[0028] As described above in detail, according to the inventions of claims 1 to 10, even if there is only one ultrasonic transmitter / receiver, it can be used by changing the directional characteristics depending on the situation. Also, by maintaining the ultrasonic transmitter / receiver horizontally, ultrasonic waves can be transmitted vertically downward, improving detection accuracy. [Brief explanation of the drawings]

[0029] [Figure 1] FIG. 1 is a side view showing an ultrasonic transmitter / receiver according to the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing an attachment for an ultrasonic transmitter / receiver in the first embodiment. [Figure 3] FIG. [Figure 4]4 is a graph showing the relationship between frequency and directivity angle in Examples 1 and 2 and a comparative example. [Figure 5] 4 is a graph showing the relationship between frequency and transmission / reception sensitivity in Examples 1 and 2 and a comparative example. [Figure 6] FIG. 10 is a cross-sectional view showing an attachment for an ultrasonic transmitter / receiver in a second embodiment. [Figure 7] FIG. 10 is a plan view showing the positional relationship between the holding member and the leveling device. [Figure 8] FIG. 10 is a cross-sectional view showing an attachment for an ultrasonic transmitter / receiver according to another embodiment. [Figure 9] FIG. 10 is a cross-sectional view showing an attachment for an ultrasonic transmitter / receiver according to another embodiment. [Figure 10] FIG. 10 is a cross-sectional view showing an attachment for an ultrasonic transmitter / receiver according to another embodiment. [Figure 11] FIG. 10 is a plan view showing the positional relationship between the holding member and the horizontality maintaining device in another embodiment. [Figure 12] FIG. 10 is a plan view showing the positional relationship between the holding member and the horizontality maintaining device in another embodiment. [Figure 13] 10A is a plan view showing the positional relationship between a holding member and a leveling device in another embodiment, and FIG. 10B is an explanatory diagram showing a method for folding the leveling device. BEST MODE FOR CARRYING OUT THE INVENTION

[0030] [First embodiment] A first embodiment of the present invention will now be described in detail with reference to the drawings.

[0031] As shown in Fig. 1, the ultrasonic transmitter / receiver 10 of this embodiment is a device for a fish finder that detects schools of fish in water by irradiating ultrasonic waves into the water. The ultrasonic transmitter / receiver 10 is used while suspended from a cable 11. The ultrasonic transmitter / receiver 10 also includes an ultrasonic transducer 12 that transmits and receives ultrasonic waves, and a case 13 that houses the ultrasonic transducer 12 in a molded state. Note that the ultrasonic transducer 12 of this embodiment is a composite transducer having piezoelectric elements such as a 0-3 composite structure, a 1-3 composite structure, and a 2-2 composite structure, and therefore the phase across the entire radiation surface is relatively uniform.

[0032] The case 13 is bell-shaped and includes a lower case 21 that forms the lower half of the case 13 and an upper case 22 that forms the upper half of the case 13. The lower case 21 is open at its upper end and has a bottom surface 23 and an outer peripheral surface 24 that is perpendicular to the bottom surface 23. The ultrasonic vibrator 12 is housed inside the lower case 21. The outer diameter of the ultrasonic vibrator 12 is slightly smaller than the outer diameter of the bottom surface 23. The bottom surface 23 of the lower case 21 is flat and functions as an acoustic radiation surface 10a for emitting (transmitting) ultrasonic waves. Furthermore, a groove 25 is formed in the outer peripheral surface 24 of the lower case 21 for receiving a screw 114 or the like shown in FIG. 10 . The groove 25 has a rectangular cross section and extends circumferentially around the cylindrical lower case 21, continuously formed around the entire circumference of the lower case 21.

[0033] 1, upper case 22 is open at the bottom and has an outer diameter that gradually decreases toward the top. A through-hole (not shown) is provided at the top end of upper case 22 for inserting cable 11 therethrough.

[0034] During normal use, the ultrasonic transmitter / receiver 10 of this embodiment is suspended from a cable 11 (see FIG. 1). However, the ultrasonic transmitter / receiver 10 can also be used with an attachment 60 (see FIG. 2) attached to it. Specifically, the attachment 60 includes an acoustic lens 81, a holding member 61, and a buoyant body 71 (a horizontality maintaining means). As shown in FIGS. 2 and 3, the holding member 61 is a substantially cylindrical member made of a resin material such as ABS resin, and is cup-shaped with a bottom portion 62, a cylindrical portion 63, and an upper end portion 64. The holding member 61 detachably holds the ultrasonic transmitter / receiver 10 such that the acoustic emitting surface 10a is acoustically connected to the flat surface 82 of the acoustic lens 81. The space defined by the bottom portion 62 and the cylindrical portion 63 forms a holding recess 65 that holds the ultrasonic transmitter / receiver 10. The inner diameter of the holding recess 65 (cylindrical portion 63) is slightly larger than the outer diameter of the ultrasonic transmitter / receiver .

[0035] Furthermore, one fitting hole 66 is provided in the bottom 62 of the holding member 61. The fitting hole 66 is circular and provided in the center of the bottom 62. The fitting hole 66 is intended to fit the convex surface 83 of the acoustic lens 81 with its flat surface 82 facing up, causing it to protrude downward from the bottom surface 61a (see FIG. 2) of the holding member 61. At this time, the outer periphery of the acoustic lens 81 is supported from below by the bottom 62. The acoustic lens 81 is detachably held to the holding member 61. Furthermore, four water supply and drainage holes 67 are formed by widening a portion of the fitting hole 66. Each water supply and drainage hole 67 has a corner located on the outer periphery of the bottom 62. The water supply and drainage holes 67 are arranged at equal angular intervals (90° intervals) based on the center C1 (see FIG. 3) of the fitting hole 66. Each water supply / drain hole 67 is for supplying water into the holding recess 65 and discharging the water in the holding recess 65 to the outside of the holding member 61 .

[0036] As shown in FIG. 2 , the buoyant body 71 is provided so as to surround the outer periphery of the holding member 61. Specifically, the buoyant body 71 is attached so as to surround the outer wall surface 63a of the cylindrical portion 63 by wrapping a strip-shaped sponge around the entire outer wall surface 63a of the cylindrical portion 63. The buoyant body 71 is formed using a material with a specific gravity lower than that of water, such as polystyrene foam, polyethylene foam, or polyurethane foam. The buoyant body 71 maintains the holding member 61, the ultrasonic transmitter / receiver 10, and the acoustic lens 81 horizontally by the buoyancy acting on itself. The buoyant body 71 has a buoyancy such that the water surface W1 reaches the flat surface 82 of the acoustic lens 81 when the ultrasonic transmitter / receiver 10 is not held in the holding recess 65.

[0037] The acoustic lens 81 is a substantially conical member made of urethane resin. Meanwhile, the portion of the ultrasonic transmitter / receiver 10 on the acoustic emission surface 10a side is made of a molded material such as rubber or urethane resin. Therefore, the specific acoustic impedance of the acoustic lens 81 is approximately equal to the specific acoustic impedance of the molded material. The sound velocity of ultrasonic waves propagating within the acoustic lens 81 is different from the sound velocity of ultrasonic waves propagating through water.

[0038] The acoustic lens 81 has a flat surface 82 and a convex surface 83 located on the opposite side. The outer diameter of the flat surface 82 is larger than the outer diameter of the fitting hole 66 and equal to the outer diameter of the acoustic emitting surface 10a. Therefore, the area of ​​the flat surface 82 is equal to the area of ​​the acoustic emitting surface 10a. The outer diameter of the flat surface 82 is slightly larger than the outer diameter of the ultrasonic transducer 12 housed in the lower case 21 of the ultrasonic transmitter / receiver 10. The tip region of the convex surface 83 (the region including the apex P1 of the acoustic lens 81) is spherical, and the region of the convex surface 83 excluding the tip region is inclined. The entire spherical surface constituting the convex surface 83 and a portion of the inclined surface constituting the convex surface 83 protrude downward from the bottom surface 61a of the holding member 61. The portion of the inclined surface is supported by the open end of the fitting hole 66 on the upper surface 61b side. Furthermore, the amount of deviation between the central axis O1 (axis passing through the vertex P1) of the acoustic lens 81 and the central axis O2 of the ultrasonic transmitter / receiver 10 is 2% or less (0% in this embodiment) of the external dimensions of the ultrasonic transmitter / receiver 10. If the amount of deviation were to be greater than 2%, the center of gravity would be shifted, causing the holding member 61, the ultrasonic transmitter / receiver 10, and the acoustic lens 81 to tilt, which could prevent ultrasonic waves from being directed directly downward.

[0039] 2, the holding recess 65 of the holding member 61 holds an acoustic lens 81 on the lower side and accommodates and holds the ultrasonic transmitter / receiver 10 on the upper side. The acoustic lens 81 is disposed on the acoustic emitting surface 10a side of the ultrasonic transmitter / receiver 10, and has the function of changing the directional characteristics of the ultrasonic waves radiated from the acoustic emitting surface 10a.

[0040] Next, a method of using the attachment 60 for the ultrasonic transmitter / receiver 10 will be described.

[0041] The ultrasonic transmitter / receiver 10 of this embodiment is used in ice fishing such as smelt fishing. In normal ice fishing, the ultrasonic transmitter / receiver 10 is immersed in water while suspended by a cable 11. Then, fish detection is performed by transmitting and receiving ultrasonic waves using the ultrasonic vibrator 12 in the ultrasonic transmitter / receiver 10. Specifically, first, the ultrasonic transmitter / receiver 10 and the LCD monitor (not shown) are turned on. The LCD monitor is used, for example, while being held by the user. The LCD monitor also includes a control device (not shown) that controls the entire device. The control device is configured by a well-known computer including a CPU, ROM, RAM, etc.

[0042] Next, the CPU of the control device controls the ultrasonic transducer 12 in the ultrasonic transmitter / receiver 10 to output an oscillation signal via the cable 11, thereby driving the ultrasonic transducer 12. At this time, the ultrasonic transducer 12 vibrates, and ultrasonic waves are emitted (transmitted) into the water from the ultrasonic transducer 12 and, ultimately, from the acoustic emission surface 10a of the ultrasonic transmitter / receiver 10. When the ultrasonic waves reach the school of fish, they are reflected by the school of fish as reflected waves, which propagate toward the ultrasonic transmitter / receiver 10 and are input (received) by the ultrasonic transducer 12. The ultrasonic waves (reflected waves) received by the ultrasonic transducer 12 are then converted into received signals and input to the CPU via the cable 11. At this point, the school of fish is detected. When the user then turns off the power, the emission of ultrasonic waves and the reception of reflected waves end.

[0043] However, there is a demand for detecting schools of fish over a wider range than usual. In this case, after the attachment 60 is attached to the ultrasonic transmitter / receiver 10, the attachment 60 is used while immersed in water (see FIG. 2). Specifically, first, the convex surface 83 of the acoustic lens 81, with its flat surface 82 facing up, is fitted into the fitting hole 66 provided in the holding member 61. This holds the acoustic lens 81 below the holding recess 65 of the holding member 61. Next, the ultrasonic transmitter / receiver 10, with its acoustic emitting surface 10a facing down, is inserted into the holding recess 65, and the ultrasonic transmitter / receiver 10 is placed on the flat surface 82 of the acoustic lens 81 fitted into the fitting hole 66. As a result, the ultrasonic transmitter / receiver 10 is housed and held in the holding recess 65, and the attachment 60 is attached to the ultrasonic transmitter / receiver 10.

[0044] Next, the ultrasonic transmitter / receiver 10 and the attachment 60 are immersed in water. At this time, water enters the holding recess 65 through the four water supply / drain holes 67 provided in the holding member 61 and enters between the flat surface 82 of the acoustic lens 81 and the acoustic radiation surface 10a of the ultrasonic transmitter / receiver 10. As a result, the flat surface 82 comes into close contact (acoustically coupled) with the acoustic radiation surface 10a via the coupling material (water in this case). Furthermore, the holding member 61, acoustic lens 81, and ultrasonic transmitter / receiver 10 float on the water and are maintained horizontally due to the buoyancy acting on the buoyant body 71.

[0045] In this state, the CPU of the control device controls the driving of the ultrasonic vibrator 12 in the ultrasonic transmitter / receiver 10. As a result, the ultrasonic vibrator 12 vibrates, and ultrasonic waves are emitted (transmitted) into the water from the acoustic emitting surface 10a of the ultrasonic transmitter / receiver 10. The ultrasonic waves emitted from the acoustic emitting surface 10a have a wider beam angle when passing through the acoustic lens 81. As a result, the directional characteristics of the ultrasonic waves become wider than the original directional characteristics, making it possible to detect schools of fish over a wider range than usual.

[0046] Next, the attachment evaluation method and the results will be described.

[0047] First, measurement samples were prepared as follows. An attachment equipped with a conical acoustic lens (conical lens) was prepared, and this was designated Example 1 (see "▲" in Figures 4 and 5). An attachment equipped with a hemispherical acoustic lens (hemispherical lens) was prepared, and this was designated Example 2 (see "●" in Figures 4 and 5). On the other hand, an attachment without an acoustic lens was prepared, and this was designated Comparative Example (see "■" in Figures 4 and 5).

[0048] Next, the directional characteristics of ultrasonic waves were verified for each measurement sample (Examples 1 and 2 and Comparative Example). Specifically, ultrasonic waves were irradiated from an ultrasonic vibrator in an ultrasonic transmitter / receiver to which an attachment was attached, and the directional characteristics during irradiation (transmission) were verified. In addition, the frequency was switched in multiple steps between 160 kHz and 300 kHz, and ultrasonic waves were irradiated at each switched frequency. Figure 4 is a graph showing the verification results of the directional characteristics of ultrasonic waves.

[0049] As a result, it was confirmed that in the comparative example in which an acoustic lens was not provided, when ultrasonic waves were radiated from the ultrasonic transducer, the directional characteristics had a relatively narrow directivity angle at all frequencies. On the other hand, in examples 1 and 2, when ultrasonic waves were radiated via an acoustic lens, the directional characteristics had a wider directivity angle than the comparative example at all frequencies. In particular, it was confirmed that example 1, which used a conical acoustic lens, had a directional characteristic with a wider directivity angle at all frequencies than example 2, which used a hemispherical acoustic lens.

[0050] Therefore, it was confirmed that irradiating ultrasound through an acoustic lens widens the beam angle of the ultrasound and widens the detection range of the ultrasound transducer.Furthermore, it was confirmed that using a conical acoustic lens widens the beam angle of the ultrasound and widens the detection range of the ultrasound transducer.

[0051] Next, a voltage was applied to the ultrasonic transducer of each measurement sample (Examples 1 and 2, and Comparative Example), and the transmission / reception sensitivity was measured at a position on the central radiation axis of the ultrasonic transducer and vertically below the ultrasonic transducer. Specifically, ultrasonic waves were first irradiated (transmitted) perpendicularly to the surface of a reflector positioned away from the ultrasonic transducer. The frequency was switched between multiple stages between 160 kHz and 300 kHz, and ultrasonic waves were irradiated at each switched frequency. The ultrasonic waves reflected by the surface of the reflector were received by the ultrasonic transducer a predetermined time after transmission, generating voltage signals at both electrodes of the ultrasonic transducer. The voltage amplitudes of the ultrasonic transducer during transmission and reception were measured using an oscilloscope, and the transmission / reception sensitivity was calculated based on the results. The results of Examples 1 and 2 and the Comparative Example are shown in FIG. 5.

[0052] As a result, it was confirmed that Examples 1 and 2, which have a wide beam angle because they irradiate ultrasound through an acoustic lens, have lower transmission and reception sensitivity at all frequencies than the Comparative Example, which has a narrow beam angle because it does not have an acoustic lens. Furthermore, in Examples 1 and 2, it was confirmed that Example 1, which has a relatively wide beam angle because it uses a conical acoustic lens, has higher transmission and reception sensitivity than Example 2, which has a relatively narrow beam angle because it uses a hemispherical acoustic lens. It was also confirmed that in both Examples 1 and 2 and the Comparative Example, the transmission and reception sensitivity was maximized at a frequency of 200 kHz. From the above, it was confirmed that using an acoustic lens makes it possible to widen the beam angle of ultrasound, but that sensitivity is reduced. It is believed that practical levels of sensitivity can be obtained by selecting an appropriate material for forming the acoustic lens.

[0053] Therefore, the present embodiment can provide the following effects.

[0054] (1) In the attachment 60 for the ultrasonic transmitter / receiver 10 of this embodiment, the ultrasonic transmitter / receiver 10 is held in the holding recess 65 of the holding member 61, and an acoustic lens 81 is disposed on the side of the acoustic emission surface 10a of the ultrasonic transmitter / receiver 10 held in the holding recess 65. In this case, even if there is only one ultrasonic transmitter / receiver 10, it is possible to change the directional characteristics of the ultrasonic waves radiated from the acoustic emission surface 10a to different directional characteristics depending on the situation. Specifically, by holding the ultrasonic transmitter / receiver 10 in the holding recess 65, the directional characteristics (directional angle) of the ultrasonic waves can be widened using the acoustic lens 81. On the other hand, by removing the ultrasonic transmitter / receiver 10 from the holding recess 65, the directional characteristics of the ultrasonic waves can be restored to their original directional characteristics.

[0055] Furthermore, by simply wrapping a strip-shaped sponge around the cylindrical portion 63 of the holding member 61, the buoyant body 71 is provided to surround the holding member 61 from the outer periphery. Therefore, even without a complex configuration (see FIG. 6 ) such as the leveling device 41 or the long screw 45, the buoyancy acting on the buoyant body 71 can keep the ultrasonic transmitter / receiver 10 and the acoustic lens 81 horizontal, and the acoustic emitting surface 10a of the ultrasonic transmitter / receiver 10 and the flat surface 82 of the acoustic lens 81 can be made horizontal. Furthermore, even if the surface 3 (see FIG. 6 ) of the ice 1 is not flat and the leveling device 41 cannot be installed, the acoustic emitting surface 10a and the flat surface 82 can be made horizontal. As a result, ultrasonic waves can be transmitted vertically downward, improving the detection accuracy of the ultrasonic transmitter / receiver 10.

[0056] (2) In this embodiment, the buoyant body 71 is provided so as to surround the holding member 61 from the outer periphery, and therefore buoyancy acts evenly on the holding member 61, making it easier to eliminate tilt of the holding member 61. As a result, the posture of the ultrasonic transmitter / receiver 10 and the acoustic lens 81 held by the holding member 61 in the water can be easily stabilized, and the acoustic emitting surface 10a of the ultrasonic transmitter / receiver 10 and the flat surface 82 of the acoustic lens 81 are reliably horizontal, making it possible to easily improve the detection accuracy of the ultrasonic transmitter / receiver 10.

[0057] (3) In this embodiment, the upper case 22 that constitutes the upper half of the case 13 has a shape that prevents snagging, and the groove portion 25 formed in the lower case 21 that constitutes the lower half of the case 13 has a shape that does not protrude from the lower case 21. This makes it difficult for the fishing line to become tangled in the case 13, especially during normal ice fishing.

[0058] (4) In this embodiment, a conical acoustic lens 81 is used as a component for changing the directional characteristics of ultrasound, which makes it possible to widen the directional angle compared to, for example, using a hemispherical acoustic lens (see FIG. 4). If the acoustic lens 81 were simply conical, there would be a problem of reduced sensitivity at a position on the central axis O1 of the acoustic lens 81 and vertically below the acoustic lens 81. In addition, it is difficult to form the tip of the cone with high precision, which also creates a problem of increased product variation. Therefore, in this embodiment, the tip region of the convex surface 83 of the acoustic lens 81 is made spherical, which solves these problems.

[0059] [Second embodiment] A second embodiment of the present invention will be described below with reference to the drawings. The following will focus on differences from the first embodiment. In this embodiment, the structure of the attachment is different from that of the first embodiment.

[0060] More specifically, as shown in Fig. 6, the attachment 30 of this embodiment includes an acoustic lens 81, a holding member 31, and a leveling device 41 (leveling means). As shown in Figs. 6 and 7, the holding member 31 is a substantially cylindrical member made of a resin material, and is configured in a cup shape by a bottom portion 32 and a cylindrical portion 33. The space defined by the bottom portion 32 and the cylindrical portion 33 forms a holding recess 34 that detachably holds the ultrasonic transmitter / receiver 10. Furthermore, a substantially columnar protruding portion 35 extending in the height direction of the cylindrical portion 33 is provided on an outer wall surface 33a of the cylindrical portion 33, and a screw hole 36 is provided in the protruding portion 35.

[0061] The leveling device 41 is a device for maintaining the holding member 31, the ultrasonic transmitter / receiver 10, and the acoustic lens 81 horizontally. The leveling device 41 is installed at the opening of a circular hole 2 formed in the ice 1 (see FIG. 6). The leveling device 41 is a plate-like member made up of a substantially annular frame body 42 that contacts the surface 3 of the ice 1 and a protruding body 43 that protrudes from the inner periphery of the frame body 42. The protruding body 43 has a screw insertion hole 44. Furthermore, as shown in FIG. 7, a long screw 45 (rod-shaped member) that connects the leveling device 41 and the holding member 31 is disposed at a position offset from the center C1 of the fitting hole 66 and the center C2 of the frame body 42 (in this embodiment, the position where the protruding body 43 is located). Then, the holding member 31, the ultrasonic transmitter / receiver 10, and the acoustic lens 81 are maintained horizontally by screwing the lower end of the long screw 45 into the screw hole 36 of the overhanging portion 35 and screwing the upper end of the long screw 45 into and inserting it through the screw insertion hole 44 of the overhanging body 43. Furthermore, since the holding member 31 is disposed inside the frame body 42 in a plan view, the ultrasonic transmitter / receiver 10 and the acoustic lens 81 held by the holding member 31 are also disposed inside the frame body 42.

[0062] Next, how to use the attachment 30 will be described.

[0063] In normal ice fishing, an ultrasonic transmitter / receiver 10 is immersed in water while suspended by a cable 11. Then, fish detection is performed by transmitting and receiving ultrasonic waves using an ultrasonic vibrator 12 inside the ultrasonic transmitter / receiver 10.

[0064] Incidentally, there is also a demand for detecting schools of fish over a wider range than usual by fixing an attachment 30 to the ultrasonic transmitter / receiver 10 and using the attachment 30 while immersed in water (see FIG. 6 ). Specifically, first, the convex surface 83 of the acoustic lens 81, with its flat surface 82 facing up, is fitted into the fitting hole 66 provided in the holding member 31. This holds the acoustic lens 81 below the holding recess 34 of the holding member 31. Next, the ultrasonic transmitter / receiver 10, with its acoustic emitting surface 10a facing down, is inserted into the holding recess 34, and the ultrasonic transmitter / receiver 10 is placed on the flat surface 82 of the acoustic lens 81 fitted into the fitting hole 66. As a result, the ultrasonic transmitter / receiver 10 is housed and held in the holding recess 34, and the attachment 30 is attached to the ultrasonic transmitter / receiver 10.

[0065] Next, the leveling device 41 is placed at the opening of the hole 2 provided in the ice 1, and the ultrasonic transmitter / receiver 10 and attachment 30 are immersed in water. At this time, water enters the holding recess 34 through the four water supply / drain holes 67 provided in the holding member 31, and enters between the flat surface 82 of the acoustic lens 81 and the acoustic emitting surface 10a of the ultrasonic transmitter / receiver 10. As a result, the flat surface 82 comes into close contact (acoustically coupled) with the acoustic emitting surface 10a via the coupling material (water in this case).

[0066] In this state, the ultrasonic transducer 12 in the ultrasonic transmitter / receiver 10 is driven to radiate (transmit) ultrasonic waves from the acoustic radiating surface 10a into the water. The ultrasonic waves radiated from the acoustic radiating surface 10a have a wider beam angle when passing through the acoustic lens 81. As a result, the directional characteristics of the ultrasonic waves become wider than the original directional characteristics, making it possible to detect schools of fish over a wider range than usual.

[0067] Therefore, according to this embodiment, the following effects can be obtained.

[0068] (5) In the attachment 30 for the ultrasonic transmitter / receiver 10 of this embodiment, the horizontal state of the ultrasonic transmitter / receiver 10 and the acoustic lens 81 held by the holding member 31 can be easily maintained by simply placing the leveling device 41 at the opening of the hole 2 provided in the ice 1. Furthermore, because the leveling device 41 is supported by the ice 1, which is solid, the horizontal state of the ultrasonic transmitter / receiver 10 and the acoustic lens 81 can be stably maintained.

[0069] (6) In this embodiment, since the holding member 31 is disposed inside the frame 42, the ultrasonic transmitter / receiver 10 (ultrasonic vibrator 12) held by the holding member 31 is also disposed inside the frame 42, i.e., close to the center of the hole 2 formed in the ice 1. This allows for appropriate fish detection directly below the hole 2.

[0070] (7) In this embodiment, the long screw 45 that connects the level maintaining device 41 and the holding member 31 is positioned at a position offset from the center C2 of the frame body 42. Therefore, the long screw 45 does not get in the way when attaching or detaching the ultrasonic transmitter / receiver 10 to or from the holding member 31. In addition, the long screw 45 is less likely to become tangled with the cable 11 that suspends the ultrasonic transmitter / receiver 10, fishing line, or the like.

[0071] The above embodiments may be modified as follows.

[0072] The acoustic lens 81 in each of the above embodiments may be selected from a plurality of types of acoustic lenses that differ from each other in at least one of dimensions (e.g., the diameter of the flat surface, the height from the center of the flat surface to the apex, etc.) and shape (e.g., the shape of the convex surface, etc.).

[0073] 8, a holding member 91 may be provided with an insertion hole 92 into which the convex surface 83 of the acoustic lens 81, with the flat surface 82 facing up, is inserted so that the convex surface 83 protrudes downward from the bottom surface 91a of the holding member 91, and the insertion hole 92 may be formed so that its inner diameter gradually increases upward. In this way, the acoustic lens 81 is held by the holding member 91 with part of the inclined surface that constitutes the convex surface 83 in surface contact with the inner surface of the insertion hole 92, making it easier to insert the ultrasonic transmitter / receiver 10 into the insertion hole 92.

[0074] In the above embodiments, the acoustic lens 81 is placed in the holding recess 34, 65 of the holding member 31, 61, but it is preferable that it is fixed to the holding member 31, 61 by fitting or gluing. If the acoustic lens 81 is not fixed to the holding member 31, 61, when the ultrasonic transmitter / receiver 10 is lifted, the attached acoustic lens 81 will be lifted up along with the ultrasonic transmitter / receiver 10, and there is a risk that it will then fall into the water.

[0075] 9, one example of a manner in which the acoustic lens 81 can be fixed is to fix an annular mounting fixture 101 to the inner periphery of the holding recess 65 of the holding member 61, and use the mounting fixture 101 to press down on the outer periphery of the flat surface 82 of the acoustic lens 81 fitted into the fitting hole 66. In this way, the acoustic lens 81 is fixed in a sandwiched state between the holding member 61 and the mounting fixture 101, so that the acoustic lens 81 can be reliably fixed and held in place.

[0076] 10 , a screw 114 (fastening member) may be inserted through a through-hole 113 formed in a cylindrical portion 112 of a holding member 111, and the tip of the screw 114 inserted through the through-hole 113 may be fitted into a groove 25 formed in the outer circumferential surface 24 of the ultrasonic transmitter / receiver 10. In this case, fitting the screw 114 into the groove 25 prevents the case 13 (ultrasonic transmitter / receiver 10) and the acoustic lens 81 located below it from coming loose, thereby ensuring the ultrasonic transmitter / receiver 10 and the acoustic lens 81 are fixed in place. Instead of using the screw 114, a permanent magnet may be provided in the groove 25, and a magnetic material such as a metal plate may be provided in a position on the cylindrical portion 112 facing the permanent magnet. In this case, the permanent magnet and the metal plate are attracted to each other and come into close contact with each other, preventing the case 13 and the acoustic lens 81 from coming loose, thereby ensuring the ultrasonic transmitter / receiver 10 and the acoustic lens 81 are fixed in place. If the screw 114 is not used, the through hole 113 and the groove 25 do not need to be provided.

[0077] Although the level-maintaining device 41 in the second embodiment described above is made up of a substantially annular frame 42, it may have other shapes. For example, as shown in Fig. 11, a level-maintaining device 121 may be made up of a single strip-shaped member 122. The strip-shaped member 122 is provided with a screw insertion hole 44 for threading and inserting the upper end of a long screw 45.

[0078] 12, the leveling device 131 may be made of a triangular frame 133 having multiple (here, three) sides 132. Adjacent sides 132 are connected via a shaft 134. A screw insertion hole 44 is provided in the center of one of the sides 132, through which the upper end of a long screw 45 is threaded and inserted. In this way, the leveling device 131 can be more stably installed in the opening of the hole 2 formed in the ice 1 than when the leveling device 131 is made of, for example, a single strip-shaped member 122 (see FIG. 11).

[0079] Furthermore, as shown in Figure 13(a), the leveling device 141 may be made of a square frame 143 having an even number of sides 142 (four in this example) equal to or greater than four, and may be foldable. The length of the diagonal of the frame 143 is longer than the inner diameter of the hole 2 provided in the ice 1, and the lengths of the sides 142 are equal to each other. A screw insertion hole 44 is provided in the center of one of the sides 142 for threading and inserting the upper end of a long screw 45.

[0080] 13(b), for example, by rotating the square-shaped frame body 143 via two shafts 144 located on a diagonal line of the frame body 143 so that adjacent sides 142 overlap, the frame body 143 is folded into a rod shape. Furthermore, by rotating the frame body 143 folded into a rod shape around the shaft 144 located at the center of the frame body 143 so that the sides 142 located on both sides of the shaft 144 overlap, the frame body 143 is folded to half its length. As a result, the level maintenance device 141 (frame body 143) is folded compactly, making the level maintenance device 141 easy to carry.

[0081] In the second embodiment, the long screw 45 is used as the rod-shaped member, but a metal rod or the like without a thread groove may also be used as the rod-shaped member.

[0082] In the above embodiments, the bottom 32, 62 of the holding member 31, 61 is provided with four water supply / drainage holes 67, but the number of water supply / drainage holes 67 may be five or more, three or fewer, or none at all. Furthermore, the water supply / drainage holes 67 are formed by widening a portion of the fitting hole 66, but they may be holes independent of the fitting hole 66.

[0083] In the above embodiments, the case 13 of the ultrasonic transmitter / receiver 10 is formed by joining the upper case 22 and the lower case 21, but the case may also be formed as a single unit.

[0084] The attachments 30 and 60 in the above embodiments are used in a fish finder, but may also be used in a measuring device such as a depth sounder that measures water depth.

[0085] Next, in addition to the technical ideas set forth in the claims, the technical ideas grasped by the above-described embodiments will be listed below.

[0086] (1) An attachment for an ultrasonic transmitter / receiver, according to any one of claims 1 to 10, characterized in that the deviation between the central axis of the acoustic lens and the central axis of the ultrasonic transmitter / receiver is 2% or less of the outer diameter dimension of the ultrasonic transmitter / receiver.

[0087] (2) In claim 5, the attachment for an ultrasonic transmitter / receiver is characterized in that the buoyant body has a buoyancy such that the water surface reaches the flat surface of the acoustic lens when the ultrasonic transmitter / receiver is not held by the holding member. In this way, when the ultrasonic transmitter / receiver is held by the holding member, the acoustic emission surface of the ultrasonic transmitter / receiver is surely in contact with the liquid (here, in contact with water), so that ultrasonic wave irradiation is not hindered by air pockets. [Explanation of symbols]

[0088] 1. Ice 2...Hole in the ice 10...Ultrasonic transmitter / receiver 10a...acoustic radiation surface 11...Cable 12...Ultrasonic vibrator 23...Bottom of ultrasonic transducer 24...Outer surface of ultrasonic transducer 25...Groove 30,60...Attachment 31, 61, 91, 111...Retaining members 32, 62...Bottom of holding member 41, 121, 131, 141...Leveling devices as a means of maintaining levelness 42,133,143…frame body 45...Long screw as rod-shaped member 61a, 91a...Bottom surface of holding member 66...Fitting hole 67…Water supply and drainage hole 71... Buoyancy body as a means of maintaining horizontality 81...acoustic lens 82…Flat surface 83…Convex surface 101...Mounting fixture 114...Screws as fastening members 142...Edge C2: Center of the frame

Claims

1. An attachment to be attached to an ultrasonic transducer for a fish finder, which is suspended from a cable, houses an ultrasonic transducer for transmitting and receiving ultrasonic waves in a molded state, and has a bottom surface that serves as an acoustic radiation surface, an acoustic lens having a flat surface and a convex surface located opposite the flat surface; a holding member that holds the acoustic lens with the flat surface facing up and detachably holds the ultrasonic transmitter / receiver so that the acoustic emission surface is acoustically connected to the flat surface of the acoustic lens; a leveling means for maintaining the ultrasonic transducer and the acoustic lens horizontally; An attachment for an ultrasonic transmitter / receiver, comprising:

2. 2. An attachment for an ultrasonic transmitter / receiver as described in claim 1, wherein the horizontal maintenance means is a horizontal maintenance device that is installed at the opening of a hole in the ice and maintains the ultrasonic transmitter / receiver and the acoustic lens horizontal.

3. The leveling device comprises a frame having a plurality of sides, a rod-shaped member connecting the leveling device and the holding member is disposed at a position offset from the center of the frame body; The holding member is disposed inside the frame.

3. The attachment for an ultrasonic transducer according to claim 2, wherein the attachment is a flexible member.

4. 4. An attachment for an ultrasonic transmitter / receiver according to claim 2, wherein the horizontality maintaining device is made of a frame having an even number of sides of four or more and is foldable.

5. 2. An attachment for an ultrasonic transmitter / receiver as described in claim 1, characterized in that the horizontal maintenance means is a buoyant body that is arranged to surround the holding member from the outer periphery, is made of a material with a specific gravity lower than that of water, and maintains the ultrasonic transmitter / receiver and the acoustic lens horizontal by the buoyancy acting on it.

6. An attachment for an ultrasonic transmitter / receiver as described in any one of claims 1 to 5, characterized in that the acoustic lens is detachably held on the holding member and is selected from a plurality of types of acoustic lenses that differ from each other in at least one of dimensions and shapes.

7. a fitting hole is provided in the bottom of the holding member into which the convex side of the acoustic lens is fitted with the flat surface facing up, so that the convex side protrudes downward from the bottom surface of the holding member; The fitting hole has a shape in which the inner diameter gradually increases upward.

7. An attachment for an ultrasonic transducer according to claim 1.

8. a fitting hole is provided in the bottom of the holding member into which the convex side of the acoustic lens is fitted with the flat surface facing up, so that the convex side protrudes downward from the bottom surface of the holding member; a mounting fixture that is fixed to the inner circumferential side of the holding member and that presses the flat surface of the acoustic lens that is fitted into the fitting hole; 7. An attachment for an ultrasonic transducer according to claim 1.

9. a fitting hole into which the convex side of the acoustic lens is fitted with the flat surface facing up so that the convex side protrudes downward from the bottom surface of the holding member; and a water supply / drain hole through which water is supplied into the holding member and through which water is discharged from the holding member, The water supply / drain hole is formed by widening a part of the fitting hole, The acoustic radiation surface of the ultrasonic transducer and the flat surface of the acoustic lens are acoustically coupled via water.

7. An attachment for an ultrasonic transducer according to claim 1.

10. An attachment for an ultrasonic transmitter / receiver as described in any one of claims 1 to 9, characterized in that a groove extending circumferentially of the ultrasonic transmitter / receiver is formed on the outer surface of the ultrasonic transmitter / receiver, and a fastening member passing through the retaining member is fitted into the groove.

Images