KR0125439Y1 - Test piece mold for with stand voltage of ultrasonic sensor device - Google Patents
Test piece mold for with stand voltage of ultrasonic sensor device Download PDFInfo
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- KR0125439Y1 KR0125439Y1 KR2019940037968U KR19940037968U KR0125439Y1 KR 0125439 Y1 KR0125439 Y1 KR 0125439Y1 KR 2019940037968 U KR2019940037968 U KR 2019940037968U KR 19940037968 U KR19940037968 U KR 19940037968U KR 0125439 Y1 KR0125439 Y1 KR 0125439Y1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/20—Preparation of articles or specimens to facilitate testing
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/12—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing
- G01R31/1227—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials
- G01R31/1263—Testing dielectric strength or breakdown voltage ; Testing or monitoring effectiveness or level of insulation, e.g. of a cable or of an apparatus, for example using partial discharge measurements; Electrostatic testing of components, parts or materials of solid or fluid materials, e.g. insulation films, bulk material; of semiconductors or LV electronic components or parts; of cable, line or wire insulation
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
- G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
- G01R31/28—Testing of electronic circuits, e.g. by signal tracer
- G01R31/282—Testing of electronic circuits specially adapted for particular applications not provided for elsewhere
- G01R31/2829—Testing of circuits in sensor or actuator systems
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Abstract
본 고안은 초음파 센서의 내전압 측정용 시편 성형금형에 관한 것이다.The present invention relates to a specimen molding mold for measuring the breakdown voltage of an ultrasonic sensor.
그 구성으로서, 본 고안은, 유전체의 절연파괴 시험용 시편의 제작시 상부몸체(330), 몸통부(320) 및 하부몸체로 이루어진 금형에 있어서, 상기 하부몸체(310)는 상부면의 중앙이 둥근모양으로 튀어나옴을 특징으로 한다.As a configuration, the present invention, in the production of the dielectric breakdown test specimen of the mold in the mold consisting of the upper body 330, the body portion 320 and the lower body, the lower body 310 is rounded the center of the upper surface Characterized by protruding into shape.
이러한 구성에 의하면, 일측의 가운데 부분이 움푹파인 균일치수의 원판형 시편을 제작하는 것이 용이하여 그 제작에 소요되는 시간의 낭비를 줄일수 있고 절연파괴 시험의 정확한 측정값을 얻을 수 있다.According to such a structure, it is easy to manufacture the disk-shaped test piece of uniform dimension in which the center part of one side is recessed, and it can reduce the waste of time which it produces, and can obtain the accurate measurement value of the dielectric breakdown test.
Description
제1도와 제2도는 내전압 측정용 시편의 형상에 따른 전속밀도분포를 도시한 설명도.1 and 2 are explanatory views showing the flux density distribution according to the shape of the test piece for withstand voltage measurement.
제3도는 본 고안에 따른 초음파 센서소자의 내전압 측정용 시편 성형금형을 도시한 구성도.Figure 3 is a block diagram showing a specimen molding mold for measuring the breakdown voltage of the ultrasonic sensor element according to the present invention.
제4도는 본 고안의 금형에 의해 제작된 시험용 시편.4 is a test specimen produced by the mold of the present invention.
제5도와 제6도는 본 고안의 금형에 의해 제작된 시편의 등방압성형 유무에 따른 절연파괴부를 도시한 설명도이다.5 and 6 are explanatory diagrams showing the dielectric breakdown part with or without isostatic pressing of the specimen produced by the mold of the present invention.
* 도면의 주요부분에 대한 부호의 설명* Explanation of symbols for main parts of the drawings
250 : 시편 251 : 전극막250: Psalm 251: electrode film
310 : 하부몸체 311 : 볼록도310: lower body 311: convexity
312 : 평활면 320 : 몸통부312: smooth surface 320: trunk portion
330 : 상부몸체330: upper body
본 고안은 초음파 센서소자의 내전압 측정용 시편 성형금형에 관한 것이다.The present invention relates to a specimen molding mold for measuring the breakdown voltage of an ultrasonic sensor element.
일반적으로 유전체 소자는 그 다양한 전기적 특성으로 인하여 여러 가지 전기부품으로 응용되어진다. 예로써, 세라믹 콘덴서, 초음파 발신/수신기용 압전소자, 무선전화기나 이동통신에 사용되는 압전형 주파수 필터등이 있다. 그리고, 이러한 유전체 소자의 대부분은 내전압 특성, 즉 어느정도의 전압을 가할때까지 파괴가 일어나지 않는가의 특성이 중요인자로 측정되어지는데, 이는 높은 전계를 인가할수록 쌍극자의 정렬이 완벽해져 전압이 가해졌을 때 팽창 또는 수축작용으로 순간적인 음파발생이 가능토록 된 압전소자등의 최대인가 전압을 알아야 하기 때문이다.In general, dielectric devices are applied to various electrical components due to their various electrical characteristics. Examples include ceramic capacitors, piezoelectric elements for ultrasonic transmitters / receivers, piezoelectric frequency filters used in wireless telephones and mobile communications. In addition, most of these dielectric elements have a high voltage characteristic, that is, the characteristics of how much breakdown does not occur until a certain voltage is measured as an important factor, which is that when a high electric field is applied, the dipole alignment is perfect and when voltage is applied. This is because it is necessary to know the maximum applied voltage of the piezoelectric element such that the instantaneous sound wave is generated by the expansion or contraction action.
이러한 내전압 측정을 위한 종래의 방법으로 최근까지는 최종제품을 그대로 사용하였다. 그런데, 이 경우에 있어서는 유전체 소자이외의 다른 부분, 즉 외피등에서 우선적으로 절연파괴가 진행되어 유전체 자체의 내전압값을 측정할 수 없는 문제점이 있었다. 한편, 외피등을 입히지 않은 유전체에 전극막을 형성하여 내전압값을 측정하는 방법이 행하여 졌는데, 이 경우에 있어서는 유전체 자체의 물성치, 즉 이론치보다 낮은 측정치가 측정되었고, 이러한 것은 제1도에 도시된 바와같이, 전극막(110)이 원판형 시편(100)의 양면에 입혀진 경우 유전체 시편(100)에 입혀진 평평한 전극막(110)의 테두리부분의 전속밀도(120)가 다른 부위보다 높다는 이론적 근거(J.M. Herbert, Ceramic Dielectrics and Capacitors, p56, Gordon and Breach Science Publis hers, NY) 및 실제 절연파괴 위치가 주로 전극막의 테두리 부분이었음이 확인되었는 바, 이를 개선하여 전속밀도가 균일한 상태로 절연내력을 측정하기 위해 제2도에 도시된 바와같이 상측이 오목한 유전체 시편(200)에 곡면화된 전극면(210)을 형성하면 그 테두리에서 전속밀도(220)가 집중되는 것을 피할 수 있음을 알았다. 따라서, 유전체의 절연내력을 측정하기 위해서는 측정시편의 형상을 전속밀도가 균일하도록 만곡형으로 하여야 한다.Until recently, the final product was used as it is in the conventional method for measuring the breakdown voltage. In this case, however, dielectric breakdown proceeds preferentially in other parts other than the dielectric element, that is, the outer shell, and thus there is a problem that the withstand voltage value of the dielectric body cannot be measured. On the other hand, a method of measuring the withstand voltage value by forming an electrode film on a dielectric material not coated with a shell or the like was performed. In this case, the physical properties of the dielectric material itself, that is, a measured value lower than the theoretical value, were measured. Similarly, when the electrode film 110 is coated on both sides of the disk-shaped specimen 100, the theoretical basis that the flux density 120 of the edge of the flat electrode film 110 coated on the dielectric specimen 100 is higher than that of other portions (JM Herbert, Ceramic Dielectrics and Capacitors, p56, Gordon and Breach Science Publis hers, NY), and the actual breakdown location was found to be mainly the edge of the electrode film.To improve this, measure the dielectric strength with a uniform flux density. For example, as shown in FIG. 2, when the curved electrode surface 210 is formed on the dielectric specimen 200 having the upper concave, the flux density 220 is concentrated at the edge thereof. It was found that could be avoided. Therefore, in order to measure the dielectric strength of the dielectric, the shape of the test specimen should be curved to have a uniform flux density.
그런데, 종래에는 전극면이 곡면화되어 전극면의 테두리에 전속밀도가 집중되지 않도록 된 시편제작은 용이하지 않아 이러한 시편가공을 위해 원판형 시편제조후, 끝이 둥근 그라인더로 곡면처리를 행하였으나, 이러한 제조방법은 그 가공시의 오차가 컸으며, 시간 소모도 막대하였던 문제점이 있었다.However, in the related art, the fabrication of a specimen in which the electrode surface is curved and so that the flux density is not concentrated on the edge of the electrode surface is not easy. Thus, after fabrication of a disk-shaped specimen for processing the specimen, the surface is curved with a round grinder. This manufacturing method had a problem that the error during processing was large, and the time consumption was enormous.
본 고안은 이러한 문제점을 해결하기 위하여 안출된 것으로서, 그 목적은, 최초 성형시에 그 일측면에 적정한 규격의 둥근 모양을 형성할 수 있도록 하여 내전압 측정을 위한 시편을 전속밀도가 집중되지 않도록 함으로써 초음파센서 소자의 내전압특성을 정확하게 측정하는 것이 가능하도록 한 초음파센서소자의 내전압 측정용 시편 성형금형을 제공함에 있다.The present invention was devised to solve such a problem, and its purpose is to make a round shape of a suitable standard on one side at the time of initial molding so that the flux density is not concentrated in the specimen for measuring the breakdown voltage. An object of the present invention is to provide a test piece molding mold for measuring the breakdown voltage of an ultrasonic sensor element which enables accurate measurement of the breakdown voltage characteristic of the sensor element.
상기 목적을 달성하기 위한 기술적인 구성으로서, 본 고안은As a technical configuration for achieving the above object, the present invention
하단부 중앙에 하부측으로 일정길이 돌출되는 원통형 돌출부를 형성한 상부몸체와, 상단부 중앙에 상부측으로 일정길이 돌출되는 원통형 돌출부를 형성하고 상기 돌출부는 외측으로 돌출하는 중앙의 볼록부와 이 볼록부 가장자리의 평활면으로 이루어지도록 된 하부몸체와, 상기 상부몸체의 돌출부와 하부몸체의 돌출부가 각각 상하부측으로부터 끼워지도록 된 관통구멍을 형성한 몸통부를 갖추어, 프레스를 이용해 몸통부에 채워지는 분체를 1차 성형한 후, 등방압성형으로 2차 성형함으로써, 일측 단부의 중앙부가 오목한 내전압 측정용 시편을 제조하기 위한 공정에서 1 차 성형용에 사용되는 유전체의 절연파괴시험용 시편 성형금형에 있어서, 시편이 내경 18㎜, 평활면의 길이 2㎜, 두께 3㎜로 성형될 때, 상기 볼록부는 그 단면이 20∼25㎜ 범위의 일정곡률을 가지는 원호형으로 형성됨을 특징으로 하는 초음파 센서소자의 내전압 측정용 시편성형금형을 마련함에 의한다.An upper body having a cylindrical protrusion protruding a predetermined length toward the lower side at the center of the lower end portion, and a cylindrical protrusion protruding a predetermined length to the upper side at the center of the upper end portion, wherein the protrusion is a central convex portion protruding outward and the edge of the convex portion is smooth. It has a lower body which is made of a surface, and a body part formed with a through hole in which the protrusions of the upper body and the protrusions of the lower body are fitted from the upper and lower sides, respectively. In the specimen molding mold for dielectric breakdown test of dielectrics used for primary shaping in the step for producing a specimen for measuring the withstand voltage in which the central portion at one end is concave, by secondary molding by isostatic pressing, the specimen has an inner diameter of 18 mm. When shaped into a length of 2 mm and a thickness of 3 mm of the smooth surface, the convex portion is one whose cross section is in the range of 20-25 mm. By providing a specimen molding mold for measuring the breakdown voltage of the ultrasonic sensor element, characterized in that formed in an arc having a positive curvature.
이하, 본 고안의 바람직한 일실시예를 첨부된 도면에 의거하여 보다 상세하게 설명한다.Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.
제3도는 본 고안에 따른 초음파 센서소자의 내전압 측정용 시편성형금형(300)을 도시한다.3 shows a specimen molding mold 300 for measuring the breakdown voltage of the ultrasonic sensor element according to the present invention.
금형(300)은 중앙부가 상측으로 일정길이 돌출된 하부몸체(310), 중앙에 상하로 관통구멍(322)을 형성한 몸통부(320) 및 중앙부가 하측으로 일정길이 돌출된 상부몸체(330)로 이루어지며, 몸통부(320)와 상부몸체(330)는 기존의 원판형 시편제작 금형과 다를 바가 없다.The mold 300 includes a lower body 310 having a central portion projecting a predetermined length upwardly, a body portion 320 having a through hole 322 formed vertically in the center, and an upper body 330 having a predetermined length projecting downwardly at a central portion thereof. It is made of, the body portion 320 and the upper body 330 is not different from the conventional disk-shaped specimen manufacturing mold.
즉, 상부몸체(330)는 하단부의 중앙에 몸통부(320)의 관통구멍(322)으로 끼워지는 대략의 원통형 돌출부(332)를 가짐으로써 적정한 힘에 의하여 상부몸체(330)가 몸통부(320)로 끼워지게 되는 것이다.That is, the upper body 330 has a substantially cylindrical protrusion 332 fitted into the through hole 322 of the body portion 320 in the center of the lower end portion of the upper body 330 by the appropriate force to the body portion 320 ) Will be inserted.
본 고안의 하부몸체(310)는 상단부측 중앙에 상측으로 일정길이 돌출된 대략의 원통형 돌출부(313)를 형성하고, 상기 돌출부(313)는 그 상단부의 중앙이 외측으로 돌출하여 단면이 원호형으로 형성되는 볼록부(311)로 이루어지며, 이러한 돌출부(313)의 상단부 외곽면, 즉 볼록부(311)의 가장자리부는 평활면(312)임을 특징으로 한다.The lower body 310 of the present invention forms an approximately cylindrical protrusion 313 protruding a predetermined length upwards in the center of the upper end side, the protrusion 313 is the center of the upper end protrudes outward so that the cross section is arc-shaped Convex portion 311 is formed, the outer surface of the upper end of the protrusion 313, that is, the edge portion of the convex portion 311 is characterized in that the smooth surface 312.
이러한 구성으로 된 시편성형금형(300)을 이용하여 시편을 제작하기 위하여는, 우선 하부몸체(310)를 프레스에 장착한 후, 그 하부몸체(310)에 몸통부(320)를 상부측으로부터 끼운다음 몸통부(320)의 상부에서 분체를 부어넣어 관통구멍(322)에 적정량의 분체가 수용되도록 한다.In order to manufacture a specimen using the specimen molding mold 300 having such a configuration, first, the lower body 310 is mounted on a press, and then the body 320 is inserted into the lower body 310 from the upper side. Next, the powder is poured from the upper portion of the body portion 320 so that the appropriate amount of powder is accommodated in the through hole 322.
물론, 이렇게 몸통부(320)의 관통구명(322)에 부어넣게 되는 분체의 양은 최종 시편의 두께를 결정하는 주요인자이므로, 내전압측정을 위한 적정크기의 시편을 형성할 수 있도록 분체의 양이 미리 적정하게 설정되어진다.Of course, the amount of powder to be poured into the through hole 322 of the body portion 320 is a major factor that determines the thickness of the final specimen, so that the amount of powder in advance to form a specimen of the appropriate size for the breakdown voltage measurement It is set appropriately.
다음에, 분체가 몸통부(320)의 관통구멍(322) 내부에서 골고루 분포되도록 하부몸체(310)와 몸통부(320) 전체를 잘 흔들어 주고, 이러한 작업이 종료되면 몸통부(320)에 상부몸체(330)를 상부측으로부터 끼워 넣는다. 이때 프레스는 약 1통(ton)/㎠ 가량의 압력으로 작동하도록 하여 시편을 제작한 후 10초 정도후에 그 시편을 꺼낸다.Next, shake the entire lower body 310 and the entire body portion 320 so that the powder is evenly distributed in the through hole 322 of the body portion 320, and when the operation is completed, the upper portion of the body portion 320 The body 330 is fitted from the upper side. In this case, the press is operated at a pressure of about 1 ton / cm 2, and then the specimen is taken out after about 10 seconds.
상기 시편을 꺼낼때는 하부몸체(310)가 상부측에 위치하도록 금형(300)전체를 뒤집어 하부몸체(310)를 상부측으로 잡아뺀 후, 하부몸체(310)의 위치에 시편 두께이상의 높이를 가지는 링(미도시)을 놓고 다시 프레스에 장착하여 약간의 힘을 가해주면 상부몸체(330)에 밀려 시편이 상측으로 올라온다.When taking out the specimen, turn the entire mold 300 upside down so that the lower body 310 is located on the upper side, pull out the lower body 310 to the upper side, and a ring having a height greater than or equal to the specimen thickness at the position of the lower body 310. Place (not shown) and again put on the press to apply a little force is pushed to the upper body 330, the specimen is raised to the upper side.
이렇게 시편이 몸통부(320)로부터 빠져나오게 되면 프레스에서 꺼내어 링을 치운 다음, 시편을 평행으로 밀면서 몸통부에서 시편정리판으로 이동시킨다.When the specimen is released from the body part 320, the ring is removed from the press, the ring is removed, and the specimen is moved from the body part to the specimen plate while pushing in parallel.
본 고안자는 대표적인 유전체인 BaTiO₃분말에 약 2중량%의 유기결합체를 섞어 본 고안의 일축형 시편 성형금형(300)에 의한 시편성형을 실시하였는바, 이에 의하여 형성되는 시편(230)(240)은 제5도 및 제6도에 나타난 바와같은 형상을 가지고, 이렇게 1차 성형된 시편(230)(240)중 하나의 시편(230)은 고무주머니에 넣어지고 그 고무주머니로부터 공기를 뺀 후 포장하여 기름속에 넣고 20,000 psi 정도의 압력을 가해 동방압성형(CIP, Cold Isostatic Press)을 실시하며, 다른 하나의 시편(240)은 그러한 등방압성형을 실시하지 않았다.The inventors performed a specimen molding by uniaxial specimen molding mold 300 of the present invention by mixing an organic binder of about 2% by weight with BaTiO₃ powder, which is a representative dielectric, and thus the specimens 230 and 240 formed by As shown in FIGS. 5 and 6, one specimen 230 of the primary molded specimens 230 and 240 is placed in a rubber bag, and the air is removed from the rubber bag and then packed. Cold Isostatic Press (CIP) was performed by applying a pressure of about 20,000 psi into oil, and the other specimen 240 did not perform such isostatic pressing.
이러한 방법으로 성형된 시편(230)(240)은 제5도 및 제6도에 도시된 바와같이, 다같이 일측의 중앙부가 움푹 파인 원판형 형상을 갖지만, 동방압성형이 이루어진 시편(230)은 그 중심부(231)에서 절연파괴가 진행되는데 반하여, 등방압 성형이 이루어지지 않은 시편(240)은 그 중심부(241)보다는 외곽측 주변부(242)에서 기공에 의한 절연파괴가 진행되기 때문에, 전체 성형물의 밀도를 균일하게 형성하여 주기 위해서는 등방성형이 중요한 인자임을 알 수 있었다.Specimens 230 and 240 molded in this way, as shown in Figs. 5 and 6, the central portion of the one side has a hollow plate-like shape, but the specimen 230 isostatically formed While the dielectric breakdown proceeds at the central portion 231, the specimen 240 without isostatic pressure molding is subjected to the dielectric breakdown due to pores at the outer peripheral portion 242 rather than the central portion 241. It was found that isotropic molding is an important factor for uniformly forming the density of.
이러한 시편이 크기를 직경(ψ) 18 ㎜, 두께(t) 3㎜, 평활면(312)의 길이(d) 2㎜ 정도로 된 제4도와 같은 시편(250)으로 형성하여 시편 요홈부의 곡률(R)을 다양한 크기로 변경하여 시험한 결과, 금형(300)의 하부몸체(310)에 갖추어진 볼록부(311)에 의한 시편의 요홈부에 대한 곡률(R)즉, 볼록부(311)의 곡률이 시편의 몰드성 및 절연파괴성능을 좌우하는 가장 중요한 요소임을 알 수 있었으며, 그 시험결과는 하기 표1에 나타낸 바와 같다.The specimen is formed of a specimen 250 as shown in FIG. 4 having a diameter (ψ) of 18 mm, a thickness (t) of 3 mm, and a smooth surface 312 having a length (d) of 2 mm. ) Is tested in various sizes, the curvature (R) of the concave portion of the specimen by the convex portion 311 provided in the lower body 310 of the mold 300, that is, the curvature of the convex portion 311 It was found that it is the most important factor that determines the moldability and dielectric breakdown performance of the specimen, and the test results are shown in Table 1 below.
즉, 상기 표 1에 의하면, 금형(300) 하부몸체(310)의 볼록부(311)에 대한 곡률(R)이 너무 작으면 시편성형시 성형물이 부수어져 불량을 야기하였고, 너무 크면 절연파괴가 시편 양단부에 형성된 전극(251)면의 테두리에서 발생되는 불량을 야기하였음을 알 수 있다.That is, according to Table 1, if the curvature R of the convex portion 311 of the lower body 310 of the mold 300 is too small, the molded product is broken when the specimen is molded, and if it is too large, the dielectric breakdown is too large. It can be seen that the defect occurred at the edge of the surface of the electrode 251 formed on both ends of the specimen.
이는 하부몸체(310)의 볼록부(311)가 이루는 곡률을 적정하게 설정하면 일측의 가운데 부분이 움푹 파인 대략의 원판형 시편을 프레스를 통해 손쉽게 만들 수 있으므로, 절연파괴시험용 시편의 제작시 시간손실을 방지하고, 시험편의 치수가 균일해지므로 그 절연파괴시험에 대한 데이터의 신뢰성을 향상시키는 것이다.If the curvature of the convex portion 311 of the lower body 310 is properly set, it is possible to easily make a roughly disc-shaped specimen in which the center portion of one side is recessed through the press, so that the time loss during the production of the specimen for dielectric breakdown test The test piece is made uniform, and the reliability of the data for the dielectric breakdown test is improved.
상술한 바와같이 본 고안에 따르면, 내경 18㎜, 평활면의 길이 2㎜, 두께 3㎜로 시편을 성형할 때, 일측의 가운데 부분인 볼록부를 그 단면이 20∼25㎜ 범위의 일정곡률을 가지는 원호형으로 형성함으로써, 내전압 측정시 전속밀도가 집중되지 않도록 방지하여 초음파센서 소자의 내전압특성을 정확하게 측정하는 것이 가능한 효과를 가진다.As described above, according to the present invention, when forming a specimen with an inner diameter of 18 mm, a smooth surface length of 2 mm, and a thickness of 3 mm, the convex portion, which is a central portion of one side, has a constant curvature in the range of 20 to 25 mm. By forming an arc shape, it is possible to prevent the concentration of flux during concentration measurement and to accurately measure the breakdown voltage characteristics of the ultrasonic sensor element.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019940037968U KR0125439Y1 (en) | 1994-12-29 | 1994-12-29 | Test piece mold for with stand voltage of ultrasonic sensor device |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| KR2019940037968U KR0125439Y1 (en) | 1994-12-29 | 1994-12-29 | Test piece mold for with stand voltage of ultrasonic sensor device |
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| Publication Number | Publication Date |
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| KR960024303U KR960024303U (en) | 1996-07-22 |
| KR0125439Y1 true KR0125439Y1 (en) | 1998-12-15 |
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