JP3302068B2 - Ultrasonic probe for medical ultrasonic diagnostic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic probe used for a medical ultrasonic diagnostic apparatus.

[0002]

2. Description of the Related Art Some ultrasonic probes used in medical ultrasonic diagnostic apparatuses have an array type transducer. When transmitting and receiving ultrasonic waves, a predetermined time delay can be set between the arrays. I have.

FIG. 4 is a perspective view showing a conventional array type transducer provided in an ultrasonic probe. A conventional array type transducer 1 includes a piezoelectric body 2 capable of transmitting and receiving ultrasonic waves, a matching layer for achieving acoustic matching between the subject and the piezoelectric body 2, that is, a matching layer 3,
An acoustic damping layer, that is, a backing layer 4 capable of absorbing ultrasonic waves traveling backward from the piezoelectric body 2 is formed in a layered structure to form a layered structure, and a predetermined groove 5 is provided in the layered structure.

In order to manufacture an array type transducer, first, the backing layer 4 is finished to a predetermined size by heating or pressing rubber or resin, and then the piezoelectric body 2 and the matching layer 3 are heated or pressed thereon. The layers 5 are sequentially connected by a pressing action or the like, and then the grooves 5 are processed into a layer structure using a dicing machine or the like to form an array structure. In these manufacturing processes, it is necessary to manage the accuracy of the completed array sufficiently to have a predetermined accuracy.

[0005]

However, first of all,
Since heating or pressing is performed when the backing layer 4 is formed, the finishing accuracy of the backing layer itself is limited. Further, even if the backing layer 4 can be finished with high accuracy, the backing layer 4 undergoes thermal expansion or contraction due to heat treatment in the step of connecting to the piezoelectric body 2,
As a result, the upper surface of the backing layer may not be parallel to the upper surface of the matching layer. Moreover, since the backing layer is made of rubber, resin, or the like, it is inherently difficult to perform machining with high accuracy.

As described above, it is difficult to ensure sufficient accuracy of the depth from the upper surface of the matching layer to the upper surface of the backing layer. Therefore, conventionally, the groove processing has been performed by setting the groove depth to a relatively large value. .

However, an increase in the groove depth not only causes a longer processing time and lowers the throughput in the groove processing step, but also results in a meandering groove, breakage of array elements, etc. when the array pitch is small. Also leads.

Further, the internal stress generated inside the backing layer during the heating step is released by the groove processing, and as a result,
There is also a disadvantage that the array pitch changes.

The present invention has been made in consideration of the above-described circumstances, and improves the groove processing throughput by ensuring the accuracy of the depth from the upper surface of the matching layer to the upper surface of the backing layer. It is an object of the present invention to provide an ultrasonic probe capable of preventing an array pitch from changing and forming an array at a fine pitch.

[0010]

In order to achieve the above object, an ultrasonic probe of a medical ultrasonic diagnostic apparatus according to the present invention has a matching layer and a backing layer formed on both surfaces of a piezoelectric body capable of transmitting and receiving ultrasonic waves. An ultrasonic probe having an array type transducer having an array structure in which a plurality of grooves are formed in a direction perpendicular to the transmitting and receiving surface of the ultrasonic wave in the layer structure, and the backing layer, A substrate layer formed of a non-metallic inorganic material or a metal material having a small amount of deformation with respect to mechanical stress and thermal stress caused by the formation of the groove; And a thin film layer having a thickness equal to one-quarter wavelength or one-quarter wavelength. For example, the groove is at a depth reaching the substrate layer beyond the matching layer, the piezoelectric body and the thin film layer, the groove is at a depth reaching the thin film layer over the matching layer and the piezoelectric body, or It is formed at a depth reaching the piezoelectric body beyond the matching layer.

[0011]

In the ultrasonic probe of the medical ultrasonic diagnostic apparatus of the present invention, when manufacturing an array-type transducer, the amount of deformation with respect to mechanical stress and thermal stress accompanying formation of a groove for forming an array structure is small. A substrate layer is formed from a non-metallic inorganic material or a metal material, and a half wavelength or a quarter of the ultrasonic center frequency is formed on the surface of the substrate layer on the piezoelectric body side.
A backing layer is formed by forming a thin film layer having a thickness equal to the wavelength.

When the backing layer is formed in this manner, the amount of deformation of the substrate layer due to mechanical stress and thermal stress when forming the groove is extremely small, so that when forming the groove, the entire backing layer is hard and distortion is reduced. That is, the depth from the upper surface of the matching layer to the upper surface of the backing layer is substantially uniform, so that the set depth of the processing groove can be made smaller than before, and the processing accuracy can be ensured.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ultrasonic probe of a medical ultrasonic diagnostic apparatus according to the present invention will be described below with reference to the accompanying drawings. Parts that are substantially the same as the parts described in the related art are given the same numbers, and descriptions thereof are omitted.

FIG. 1 is a perspective view showing an array-type transducer provided in an ultrasonic probe of a medical ultrasonic diagnostic apparatus according to the present embodiment.

The array type transducer 11 has a layer structure in which a matching layer 3 and a backing layer 12 are connected to both surfaces of a piezoelectric body 2 capable of transmitting and receiving ultrasonic waves, and a predetermined groove 5 is formed in this layer structure. It has an array structure.

The matching layer 3 is provided for acoustic matching between a subject (not shown) and the piezoelectric body 2.

The piezoelectric body 2 is preferably made of, for example, piezoelectric ceramics. Electrodes (not shown) are provided on both sides of the piezoelectric body 2 for supplying electric power for ultrasonic oscillation and extracting electric signals in response to the received ultrasonic waves.

The backing layer 12 is configured to absorb, for example, backward ultrasonic waves. In this embodiment, the backing layer 12 forms the substrate layer 13 with a material whose deformation amount with respect to mechanical stress and thermal stress is a predetermined value or less, for example, a nonmetallic inorganic material such as glass or ceramics, a metal material, or the like. On the layer 13, the thin film layer 14 is formed uniformly so that the thickness t becomes, for example, a quarter wavelength of the ultrasonic center frequency. The thin film layer 14 is preferably made of an epoxy resin, a polyester resin, a polyethylene resin, or the like.

As can be seen in FIG.
The substrate layer 13 is formed over the piezoelectric body 2 and the thin film layer 14.

[0020] When the thickness t of the thin film layer 14 was a quarter wavelength of the ultrasonic center frequency, the acoustic impedance Z _B of the whole backing layer 12 facing the back side of the piezoelectric body 2,

The Equation 1] ^{_{Z B = Z L 2 / Z}} G. Here, Z _L and Z _G are the thin film layer 14,
This is the acoustic impedance of the substrate layer 13.

In order to manufacture the array type transducer of this embodiment, first, the substrate layer 13 is formed to a predetermined size with glass, ceramics or the like.

Next, the thin film layer 14 of epoxy resin or the like is connected on the substrate layer 13 by processing such as heating and pressurizing.

Next, the piezoelectric body 2 and the matching layer 3 are sequentially connected to the thin film layer 14 by processing such as heating and pressurizing.

Next, a groove 5 having a depth D, a width W and a pitch p is processed by a dicing machine or the like.

Finally, a filler such as a silicone adhesive is put into the groove 5.

As described above, the ultrasonic probe according to the present embodiment is made of a material whose deformation with respect to mechanical stress and thermal stress is equal to or less than a predetermined value, for example, glass, ceramic or the like.
Is formed, the substrate layer 13 can be finished with high precision by a known technique.

Further, since the substrate layer 13 is hardly deformed by the action of heat or pressure, the finishing accuracy can be maintained at a high level even after the thin film layer 14 is connected. Therefore, the depth D ′ from the upper surface of the matching layer 3 to the upper surface of the substrate layer 13 is less scattered depending on the location, and the depth D of the groove 5 is set to a smaller value than in the related art. The amount can be reduced and the processing time can be shortened.

In addition, since the substrate layer 13 is made of glass or the like, even if the substrate layer 13 is firmly held for groove processing, it hardly deforms, and on the other hand, it can be easily processed. For this reason, the throughput of the groove processing step is significantly improved.

In addition, the possibility that the internal stress is released during processing to affect the array pitch p is reduced.
An array with a fine pitch can be easily manufactured.

Further, since the thin film layer is interposed between the substrate layer and the piezoelectric body, the acoustic impedance of the entire backing layer can be appropriately combined with the acoustic impedance of the thin film layer, the thickness of the thin film layer, and the acoustic impedance of the substrate layer. The impedance can be adjusted to any value.

In the above-described embodiment, the thickness t of the thin film layer 14 is set to 中心 of the center frequency of the ultrasonic wave. However, the thickness is not limited to this and can be set arbitrarily.
For example, it may be set to a half of the ultrasonic center frequency. In this case, the backing layer 12 viewed from the back side from the piezoelectric body 2
Overall acoustic impedance _{Z B} is

The [number 2] _{Z B} = Z _G.

In the above-described embodiment, the groove 5 is formed up to the substrate layer 13 beyond the matching layer 3, the piezoelectric body 2, and the thin film layer 14. However, the present invention is not limited to this. As described above, the groove 5 may be formed halfway of the thin film layer 14 beyond the matching layer 3 and the piezoelectric body 2, or as shown in FIG. May be formed. In the example of FIG. 3, the thickness T 'of the portion of the piezoelectric body 2 remaining after the formation of the groove 5 is set to 5 times the thickness T of the normal portion.
It is better to make it 1 / less or less.

In the above-described embodiment, an example is shown in which the present invention is applied to a medical ultrasonic diagnostic apparatus. However, the ultrasonic probe of the present invention is not limited to this. The present invention can also be applied to the ultrasonic probe used in the above.

In the above embodiment, after the thin film layer is formed on the substrate layer, the piezoelectric body and the matching layer are formed on the thin film layer. Instead, the thin film layer is formed on the back surface of the piezoelectric body in advance. In advance, this may be connected to the substrate layer.

[0035]

As described above, the ultrasonic probe of the medical ultrasonic diagnostic apparatus of the present invention has a layer structure in which a matching layer and a backing layer are formed on both surfaces of a piezoelectric body capable of transmitting and receiving ultrasonic waves. An array-type transducer in which a plurality of grooves are formed in the layer structure from a direction perpendicular to the ultrasonic wave transmitting / receiving surface to form an array structure, and the backing layer is provided with mechanical stress and thermal stress accompanying the formation of the grooves. A substrate layer formed of a non-metallic inorganic material or a metal material having a small deformation amount with respect to the substrate, and a half-wave or a quarter-wave of the ultrasonic center frequency formed on the surface of the substrate layer on the piezoelectric body side. Since it is composed of thin film layers having the same thickness, the accuracy of the depth from the upper surface of the matching layer to the upper surface of the backing layer is ensured to improve the throughput of groove processing. So change does not occur, it is possible to form the array at very small pitches.

[Brief description of the drawings]

FIG. 1 is a perspective view of an array-type transducer provided in an ultrasonic probe of a medical ultrasonic diagnostic apparatus according to the present embodiment.

FIG. 2 is a perspective view showing a modified example of the array-type transducer of the embodiment.

FIG. 3 is a perspective view showing another modified example of the array-type transducer of the embodiment.

FIG. 4 is a perspective view of an array-type transducer provided in a conventional ultrasonic probe.

[Explanation of symbols]

 2 Piezoelectric body 3 Matching layer (matching layer) 5 Groove 11 Array transducer 12 Backing layer 13 Substrate layer 14 Thin film layer

Claims (4)

(57) [Claims] 1. A layer structure in which a matching layer and a backing layer are respectively formed on both surfaces of a piezoelectric body capable of transmitting and receiving ultrasonic waves, and a plurality of grooves are formed in the layer structure from a direction perpendicular to the ultrasonic wave transmitting / receiving surface. An ultrasonic probe of a medical ultrasonic diagnostic apparatus having an array type transducer having an array structure, wherein the backing layer is formed of a non-metallic inorganic material having a small amount of deformation with respect to mechanical stress and thermal stress accompanying the formation of the groove. Or a substrate layer formed of a metal material and a thin film layer formed on the surface of the substrate layer on the piezoelectric body side and having a thickness equal to a half wavelength or a quarter wavelength of the ultrasonic center frequency. An ultrasonic probe for a medical ultrasonic diagnostic apparatus, comprising: 2. The semiconductor device according to claim 1, wherein the groove is formed to a depth reaching the substrate layer beyond the matching layer, the piezoelectric body, and the thin film layer.
An ultrasonic probe for the medical ultrasonic diagnostic apparatus according to the above. 3. The ultrasonic probe of a medical ultrasonic diagnostic apparatus according to claim 1, wherein said groove is formed at a depth reaching said thin film layer beyond said matching layer and piezoelectric body. 4. The ultrasonic probe according to claim 1, wherein the groove is formed at a depth reaching the piezoelectric body beyond the matching layer.