JP2007271562A - Micromass measuring sensor and method of using same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a micromass measuring sensor markedly reduced in the deterioration of a QCM sensor element during preservation, having high measuring reliability and easy to handle. <P>SOLUTION: The QCM sensor element is supported by the supports fixed to two metal terminals piercing through a metal base in an airtight manner, the case for covering the sensor element is joined to the metal base in an airtightly sealed state, at least two recesses are formed to the outside surface of the case, one of the recesses is provided in the vicinity of the central part of the interval between the end on the side opposite to the vertical direction of the sensor element metal base and the inner surface of the case in the vertical direction, this interval is at least more than 1/6 of the maximum diameter of the GCM sensor element and less than the maximum diameter, at least two holes are bored in the GCM sensor element during measurement so as to airtightly destruct the GCM sensor element, a specimen is injected from the preceding hole and measurement is performed while discharging the specimen from the separate port not used in the injection of the specimen. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

          The present invention relates to a sensor for measuring a minute mass, in which deterioration of the sensor element for measuring a minute mass during storage is extremely small, the measurement reliability is extremely high, and the sensor is easy to handle, and a measuring method using the sensor for measuring the minute mass About.

Sensor element for measuring minute mass (QCM: Quartz) using an AT-cut crystal unit
The crystal microbalance sensor element utilizes the thickness-shear vibration of a crystal, and a metal film made of a material in consideration of adhesion to the crystal substrate is formed on the surface of the crystal substrate. A sensor element for measuring a minute mass (hereinafter referred to as a QCM sensor element) is used as a sensor for measuring a minute mass (hereinafter referred to as a QCM sensor) when used in either a gas phase or a liquid phase. Due to the need for physical contact with an analyte, individual QCM sensor elements were manufactured without being hermetically sealed, stored in that state until the time of measurement, and often used after being cleaned.

          In addition, in the QCM sensor, a minute weight change when the sample to be measured adheres to or separates from the surface of the crystal unit is regarded as a frequency change of the crystal unit, but this sample adheres to the surface of the crystal unit. Basically, the QCM sensor adopts a disposable method, and in terms of its analysis accuracy, it is effective to measure in the high frequency band where the stability of temperature control is high and the frequency variation per unit weight is large. Yes.

          As described above, most of the QCM sensors have a structure in which the main surface of the crystal unit is exposed for the purpose of use, and each QCM sensor element is provided in a recess provided in a tray made of plastic or the like during storage and transportation. The crystal resonators were arranged so as to be dropped so as not to be damaged as much as possible, and were covered with a lid from above.

JP 2003-222580 A Patent 3682474

          In addition, the applicant did not find any prior art documents related to the present invention by the time of filing of the present application other than the prior art documents specified by the above prior art document information.

          However, conventionally, as described above, when storing and transporting the QCM sensor, since it is stored in the atmosphere until it is packed and used, a sensitive film is formed on the surface of the QCM sensor element. In such a case, there is a problem that the metal film including the sensitive film is easily deteriorated, and in the case where the sensitive film is not formed, the metal film which is the excitation electrode in the crystal resonator is easily deteriorated.

          Further, the QCM sensor element is swung without being completely fixed in the storage / transport tray, and the inner wall of the concave portion provided in the tray and the QCM sensor element rub against each other, resulting in damage to the QCM sensor element, There is a problem that the measurement accuracy of the QCM sensor may be remarkably lowered, for example, the main surface is contaminated.

          In addition, in order to fix the QCM sensor so that it does not swing during storage and transportation of the QCM sensor, the QCM sensor is also used when the QCM sensor is fixed and stored and transported using a sponge-like cushioning material. As a result, the dust generated from the storage / transport container adheres to the sensitive film of the QCM sensor element and the metal film that is the excitation electrode of the crystal unit. There was a problem that it might be lowered.

          The present invention has been made under the technical background as described above. Therefore, the purpose of the present invention is that the deterioration of the QCM sensor element during storage is extremely small and the reliability of measurement is extremely high. It is to provide a measurement method using a QCM sensor that is easy to handle and a sensor for measuring a minute mass.

          In order to achieve the above object, the present invention provides a QCM sensor using a crystal resonator formed by forming a metal film on the surface of a quartz substrate, wherein the QCM sensor element has two metal terminals hermetically penetrating the metal base. The case that covers the QCM sensor element is bonded to the metal base, and the QCM sensor element is hermetically sealed, and the outer surface of the case has at least two airtights of the QCM sensor. It is characterized in that a recess having a reduced thickness is formed.

          In addition, one of the recesses is near the center of the distance between the end of the metal base of the QCM sensor element opposite to the vertical direction and the case inner surface in the vertical direction, and this distance is at least 6 minutes of the maximum diameter of the QCM sensor element. It is characterized by being 1 or more and the maximum diameter or less.

          In addition, a sensitive film is formed on the surface of the metal film of the QCM sensor element.

          In addition, at the time of measurement, at least two or more holes are made in the QCM sensor case to break the airtightness, the sample is injected from the previous hole, and the sample is discharged from another hole that is not used for sample injection. It is a measuring method using a QCM sensor for performing the above.

          According to the QCM sensor of the present invention, the contamination due to dust particles adhering to the surface of the crystal unit, which significantly affects the measurement accuracy, is remarkably reduced until the measurement, and the measurement accuracy of the QCM sensor is significantly affected. It is possible to protect the main surface of the crystal resonator from damage for a long time until measurement.

          In addition, according to the present invention, it is possible to remarkably suppress chemical changes such as the formation of an oxide film on the surface of a quartz crystal or its metal film or the sensitive film, which significantly affects the measurement accuracy. A highly reliable and reliable QCM sensor can be obtained.

          Further, according to the present invention, handling as a QCM sensor becomes very easy, and it is not necessary to use a special material / structure for the storage / conveying container of the QCM sensor until the measurement is performed, thereby reducing the cost.

          Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In addition, the same code | symbol in each figure shall show the same object.

          FIG. 1 is a schematic diagram of a QCM sensor according to the present invention viewed from the direction of the principal surface of a metal film 2 formed on the surface of a crystal resonator. That is, the QCM sensor element 4 is supported by a support 7 fixed to two metal terminals 6 that airtightly penetrate the metal base 5, and a case 8 that covers the QCM sensor element 4 is joined to the metal base 5 to join the QCM sensor element 4. Is further hermetically sealed, and at least two or more recesses 10 are formed on the outer surface 9 of the case so that the airtightness of the QCM sensor 3 can be easily broken by making a hole. . In addition, one of the recesses 10 is near the center of the interval 13 between the end 11 on the opposite side of the metal base 5 of the QCM sensor element 4 and the case inner surface 12 in the vertical direction, and this interval is at least the QCM sensor element 4. 1/6 or more of the maximum diameter 14 and not more than the maximum diameter. Unlike a conventional QCM sensor, the QCM sensor 3 is hermetically sealed until a gas or liquid that is a specimen at the time of measurement is physically brought into contact with the metal film 2. If the QCM sensor 3 is sealed in a nitrogen atmosphere or a vacuum atmosphere, the sensitive film and the quartz vibration can be obtained not only when the sensitive film is formed on the surface of the QCM sensor element 4 but also when the sensitive film is not formed. An oxide film can be prevented from being formed on the surface of the metal film 2 that is the excitation electrode of the child, and the QCM sensor 4 having high measurement reliability can be obtained. The QCM sensor 3 according to the present invention can be handled in the same manner as a general electronic component at the product shipment stage, and has an effect that the handling can be remarkably facilitated as compared with the prior art. Although not shown in the figure, a sensitive film that reacts with the specimen may be formed on the surface of the metal film 2 on the surface of the QCM sensor element 4, and in this case, the technical scope of the present invention Needless to say, it is included in 1 and 2, the shape of the QCM sensor element is depicted as a circle, but it may be a rectangle, a quadrangle, a polygon, or an ellipse. These cases are also included in the technical scope of the present invention. Needless to say. Furthermore, it goes without saying that the surface mount type QCM sensor element in which the QCM sensor elements are mounted in the horizontal direction is also included in the technical scope of the present invention.

          FIG. 2 is a schematic schematic view of the QCM sensor 4 as viewed from the principal surface direction of the metal film 2 showing one embodiment of the measurement using the QCM sensor 4 which is a measurement method using the QCM sensor of the present invention. . That is, in the measurement method using the QCM sensor element 4 formed by forming the metal film 2 on the surface of the quartz substrate 1 and using the QCM sensor 3 in which the QCM sensor element 4 is hermetically sealed, A QCM sensor 3 that performs measurement while opening at least two or more holes in the case 8 of the sensor 3 to break the airtightness, injecting the sample from the above-mentioned hole, and discharging the sample from another hole that is not used for injection of the sample. It is the figure which showed the mode of the measurement using this.

          When the case 8 is used for measurement as the QCM sensor 3, a hole that breaks the airtightness of the QCM sensor 3 of the present invention is formed in at least two places using a jig (conduit) as shown in FIG. After that, the specimen is flowed into the QCM sensor 3 from the outside through a jig (conduit) as shown in FIG. In FIG. 2, the hole positions for breaking the hermeticity of the QCM sensor 4 are also shown in a straight line in the horizontal direction. It doesn't matter. In FIG. 2, the QCM sensor 3 of the present invention is housed in a housing made of resin or metal for measurement. The casing is made so as to fit the outer shape of the QCM sensor 3 and not to create a gap between the inner surface of the casing. In the QCM sensor 3 of the present invention, one of the recesses 10 is near the center of the interval 13 between the end 11 on the opposite side of the metal base 5 of the QCM sensor element 4 and the case inner surface 12 in the vertical direction. Is at least one-sixth of the maximum diameter 14 of the QCM sensor element 4 and not more than the maximum diameter, so that a hole that breaks the airtightness of the QCM sensor 4 is opened when measuring a gas phase or liquid phase specimen. At this time, there is no possibility of causing damage or damage to the QCM sensor element 4 due to the contact of the jig (conduit) flowing into the QCM sensor with the QCM sensor element 4, and highly reliable measurement can be performed. In FIG. 2, the QCM sensor 3 of the present invention is housed in the casing for measurement, but the casing may be made of resin or metal, and the casing can be opened when a hole is made in the casing. Needless to say, it is necessary to match the inner dimensions of the QCM sensor 3 and the outer shape of the QCM sensor 3 of the present invention without loosening in order to suppress unnecessary deformation of the QCM sensor 3 when making a hole.

          FIG. 3 is a schematic diagram of an example of a conduit that is a jig that penetrates the case 8 of the QCM sensor through the recess 10 and is used when measurement is performed using the QCM sensor of the present invention as viewed from the side. The conduit of FIG. 3 has a hole in the side surface of the tip, and the conduit is inserted unnecessarily inside the QCM sensor 3 by having a stopper with a step, so that the tip of the conduit is There is no contact with the QCM sensor element.

          FIG. 4 is a schematic diagram showing a conventional QCM sensor element 3 as viewed obliquely from above. Conventionally, since the QCM sensor element 4 is stored in the atmosphere without being hermetically sealed during storage and transport of the QCM sensor 3, that is, until it is packed and used, the QCM sensor element 4 When the sensitive film is formed on the surface, the sensitive film, the metal film 2, and even when the sensitive film is not formed, the metal film 2 that is the excitation electrode of the crystal resonator is deteriorated, such as being oxidized. There was a problem that it was easy.

          FIG. 5 is a schematic diagram showing a state in which the conventional QCM sensor 3 is accommodated in a storage / conveyance container as seen from an obliquely upward direction. Conventionally, when the QCM sensor 3 is stored and transported, the QCM sensor 3 cannot be completely fixed in the tray, and the QCM sensor 3 swings in the vertical and horizontal directions in the recess provided in the tray. The inner wall of the concave portion of the tray and the surface of the QCM sensor 3 rub against each other, and as a result, there is a risk of generating dust that may cause contamination that significantly reduces the measurement accuracy of the QCM sensor 3.

It is the schematic model which looked at the QCM sensor of this invention from the metal film main surface direction formed in the surface of the crystal oscillator. It is the schematic diagram seen from the metal film main surface direction of the QCM sensor which showed one form at the time of measuring using the QCM sensor of this invention. It is the schematic model which looked at the example of the conduit | pipe which penetrates the case of a QCM sensor in a recessed part used when measuring using the QCM sensor of this invention from the side surface direction. It is the schematic model which looked at the QCM sensor element from diagonally upward. It is the schematic diagram seen from the diagonally upward direction which shows a mode that the conventional QCM sensor is accommodated in the conventional storage and conveyance container.

Explanation of symbols

1 Crystal substrate 2 Metal film 3 Sensor for measuring minute mass (QCM sensor)
4 Sensor element for measuring minute mass (QCM sensor element)
5 Metal base 6 Metal terminal 7 Support 8 Case 9 Case outer surface 10 Recess 11 End 12 Case inner surface 13 Spacing 14 Maximum diameter of sensor element for measuring minute mass (QCM)

Claims (4)

In a sensor for measuring a minute mass using a crystal resonator formed by forming a metal film 2 on the surface of a crystal substrate 1,
A sensor element for measuring a minute mass is supported by a support fixed to two metal terminals hermetically penetrating the metal base, and a case covering the sensor element for measuring the minute mass is joined to the metal base and the minute mass The measurement sensor element is hermetically sealed, and the outer surface of the case is formed with at least two or more concave portions whose thickness is reduced so as to easily break the hermeticity of the sensor for measuring a minute mass. Sensor for mass measurement.           One of the recesses is in the vicinity of the center of the gap between the end of the metal base opposite to the vertical direction of the metal base of the minute mass measurement sensor and the inner surface of the case in the vertical direction, and the gap is at least the minute mass measurement. The sensor for measuring a minute mass according to claim 1, wherein the sensor is not less than 1/6 of the maximum diameter of the sensor element for use and not more than the maximum diameter.           2. The sensor for measuring a minute mass according to claim 1, wherein a sensitive film is formed on the surface of the metal film of the sensor element for measuring the minute mass. In a measurement method using a sensor element for measuring a minute mass formed by forming a metal film on the surface of a quartz substrate, and using a sensor for measuring a minute mass in which the sensor element for measuring a minute mass is hermetically sealed,
At the time of measurement, at least two or more holes are opened in the case of the sensor for measuring a minute mass to break the airtightness, the sample is injected from the hole, and the sample is injected from another hole not used for injection of the sample. Measurement method using a sensor for measuring minute mass while measuring while discharging.

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