JPH02220344A - Multiple electrode and manufacture thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a multipole electrode used in ion lenses, mass spectrometers, etc., and a method for manufacturing the same.

(b) Prior Art Generally, in mass spectrometers, quadrupole electrodes with a relatively simple structure are sometimes used to perform mass separation of ions.

As shown in FIG. 5, a conventional quadrupole electrode has four electrode rods a1 to a4 arranged in parallel, and a predetermined voltage ψ (= U + V cos ωt, U is a direct current) to each electrode rod a1 to a4. By applying a voltage (V cosωt is a high-frequency alternating current voltage), a quadrupole electric field is formed inside it. Then, by introducing ions into this four-electrode electric field and changing the ratio (2) while keeping the U/V ratio constant, mass scanning is performed to obtain a mass spectrum.

Theoretically, it is most desirable for the shape of each of the electrode rods a+-a to have a hyperbolic inner cross section in view of the electric field distribution. However, it is extremely difficult to accurately process the inner cross sections of the electrode rods a, to a4 into a hyperbolic shape, resulting in poor manufacturing yield. For this reason, conventionally, a cylindrical shape, which is considered to be almost equivalent to this, has been used.

However, in recent years, there has been a strong demand for higher precision in mass spectrometers, and it has therefore become necessary to make the picture electrode electric field as close as possible to the theoretical hyperbolic distribution.

Conventionally, as long as electrode rods are used, there is a limit to the processing accuracy and the production yield is also poor. Therefore, in the conventional technology, a glass tube is placed on a mandrill and heated, and then the inside of the glass tube is heated. A method has been proposed in which a glass tube softened by exhaust or external pressure is brought into close contact with a mandrill, and the mandrill is removed after cooling to form a multi-electrode electrode shaped as shown in Fig. 6 (
For example, see US Patent No. 3,328,146)
According to this method, the shape of the electric field forming electrodes C3 to C4 provided inside each electrode forming part b1 to b4 becomes a highly accurate hyperbola, and furthermore, it has advantages such as easy manufacturing and excellent yield. be.

(c) Problems to be Solved by the Invention However, in the case of the structure shown in FIG. 6, each electrode forming part is
The connecting portions d and ~d4 where -b4 asymptotically approaches each other must be formed into a tapered shape. In this way, each connection part d
If electrodes 1 to d4 are located close to the quadrupole electric field generation point and occupy a small proportion of the electrode formation area S, -b, a high voltage is applied to the electrodes c1 to c4 to generate a strong electric field. When generated, charges are accumulated in the connecting portions d and -d. This charge accumulation affects the quadrupole layer field, and even when the applied voltage is changed, the electric field is distorted, resulting in problems such as not being able to obtain the desired analysis accuracy.

In order to solve the problem of charge accumulation in the connecting parts d and -d, it has been proposed to form a high-resistance conductive film along the inner peripheral surfaces of the connecting parts d and -d4. (See, for example, European Patent: Publication No. 0268048).

If such a conductive film is formed, charge accumulation is relatively quickly discharged through the electrodes C1 to C3, and distortion of the quadrupole layer field is prevented, but on the other hand, direct current and AC loss increases, causing problems such as an increase in the size of the power supply, instability of the electric field, and heat generation.

(d) Means for Solving the Problems The present invention has been made in view of the above circumstances, and provides a multi-electrode electrode that eliminates the influence of charge accumulation at the connecting portion and is easy to manufacture. The present invention provides a method.

Therefore, in the present invention, a plurality of electrode forming parts provided with electrodes for forming a multipolar electric field and a connecting part that connects mutually adjacent parts of these electrode forming parts and maintains the positional relationship are integrally formed. In the multipole electrode, the connecting portion is configured to bulge outward away from the location where the multielectrode electric field formed by the electrodes is generated.

In addition, when manufacturing this multi-electrode electrode, a first mold material for molding the connecting part and a second mold material for molding the electrode forming part are used.
A mandrill is constructed by combining the molded materials with each other, and a glass tube is placed over the mandrill, heated, and the interior of the glass tube is evacuated or pressurized from the outside to make the softened glass tube adhere to the mandrill, and after cooling, The mandrill was removed to obtain a multipolar electrode. Moreover, a conductive paste is applied in advance to required locations inside the glass tube before heating, and electrodes are formed by firing the conductive paste at the same time as the glass tube is heated.

(E) Since the action connection part bulges out to the outside with respect to the electrode formation part,
The creepage distance between the electrodes on the inner surface of the connecting portion becomes longer.

Therefore, the charge density accumulated in the connecting portion becomes relatively low. Moreover, since the location where charges are accumulated in the connection portion is located away from the location where the multi-electrode electric field is generated, the influence of the accumulated charges on the multi-electrode electric field is reduced.

In addition, during cooling contraction in the acid type process of multipole electrodes,
Since the first mold material for molding the connecting portion and the second mold material for molding the electrode forming portion contract independently from each other,
The first and second mold members are smoothly released from the mold without being caught in the constriction between the electrode forming part and the connecting part. Moreover, since the electrodes for forming the multipole electric field are formed simultaneously by heating and cooling the glass tube, the number of manufacturing steps is simplified compared to the case where electrodes are separately provided inside the glass molded product.

(f) Example In this example, a case where the present invention is applied to a quadrupole electrode will be explained.

FIG. 1 is a cross-sectional view of a quadrupole electrode. The quadrupole electrode 1 of this embodiment includes four electrodes 2 for forming a four-electrode electric field.
It includes two electrode forming parts 4 and a connecting part 6 that connects mutually adjacent parts of these electrode forming parts 4 to maintain a positional relationship, and each of these parts 4.6 is integrally formed as a glass molded product. .

Each of the above electrodes 2 is connected to the entire inner surface of the electrode forming part 4 and the connecting part 6.
A picture electrode electric field is formed by applying a voltage to each of these electrodes 2 . Moreover, each inner surface of the electrode forming part 4 is formed into a hyperbolic shape so that a required electric field distribution can be obtained. Further, the connecting portion 6 is bulged in an arc shape outward away from the location where the multi-electrode electric field generated by the electrodes 2 is generated.

In the above configuration, since the connecting portion 6 bulges outward with respect to the electrode forming portion 4, the creepage distance between the electrodes 2 on the inner surface of the connecting portion 6 becomes long. Therefore, good insulation,
Pressure resistance is ensured. In addition, charge usually accumulates in the center of the inner surface of the connecting portion 6, but since the creepage distance at the connecting portion 6 is long, the charge density accumulated in the connecting portion 6 is relatively low, and the charge accumulation location is Since it is separated from the location where the multipole electric field is formed, the influence of this accumulated charge on the multipole electric field is reduced.

Next, a method for manufacturing this multi-electrode electrode 1 will be explained.

A mandrill IO having the shape shown in FIG. 2 is prepared in advance.

This mandrill IO is the first
A second mold material 14 for forming the mold material 12 and the electrode forming part 2
It consists of. Both mold members 12 and 14 are made of alloy steel or the like, and the first mold member 12 is formed to fit into the end of the second mold member 14, and the second mold member 14 has a hyperbolic cross section. It is precisely machined.

When manufacturing the multipole electrode I, the above-mentioned eleventh and second mold members I2.14 are combined with each other to constitute the mandrill IO. Then, the mandrill IO is covered with a glass tube, and the interior of the glass tube is evacuated with a vacuum pump while being heated, thereby bringing the softened glass tube into close contact with the mandrill 10. Thereafter, when it is cooled, the glass hardens and the mandrill 0, which has a higher coefficient of thermal expansion than the glass, contracts. In that case, the first mold material 12 and the second mold material I4 are independent from each other, and therefore can be individually contracted. Therefore, each of the shapes 12, 14 of the mandrill 10 transitions from the state shown in FIG. 3(a) to the state shown in FIG. 3(b) as it shrinks on cooling. As a result, the first and second mold members 12.14 are not caught in the constricted portion between the electrode forming portion 4 and the connecting portion 6, and both mold members 12.14 are smoothly released from the mold.

After removing the 11th and 2nd mold members 12.14,
By forming the electrodes 2 at required locations on the inner surface of the electrode forming portion 4 of this glass molded product, the desired multipole electrode I can be obtained.

Note that as the glass tube, glass for electrical materials such as quartz glass and borosilicate glass can be used. Also,
The electrode 2 can be formed by applying or vapor depositing a conductive paste containing Ag or Pt as a component. Also,
If a conductive paste is applied in advance to the required locations inside the glass tube before heating, the electrodes can be formed by firing the conductive paste at the same time as heating the glass tube, without having to perform a separate process for forming the electrode 2. This is advantageous because it can be done. Furthermore, instead of evacuating the inside of the glass tube, the glass tube can be brought into close contact with the mandrill by applying pressure from the outside.

When the quadrupole electrode l obtained in this way is to be attached to a mass spectrometer, for example, as shown in FIG. A contact member 18 is provided on this holding rod 16, and the contact member 18 can be electrically connected to the electrode 2. In this way, the connecting portion 6 serves as a means for positioning and holding the quadrupole electrode 1, so that assembly accuracy can be improved.

In addition, although the above-mentioned example explained a quadrupole electrode, it is not limited to this, and can be applied to any multipole electrodes, such as an octupole electrode and a dedupole electrode. Further, the inner surface shape of the connecting portion does not necessarily have to be an arcuate shape, and it is also possible to adopt a shape such as an ellipse.

(g) Effects According to the present invention, it is possible to eliminate the influence on the multi-electrode electric field due to charge accumulation in the connecting portion, and moreover, the edge distance between the conductive layers is increased, resulting in good insulation and voltage resistance. can get.

Further, since the connecting portion serves as a positioning and holding member when assembling a device such as a quality analyzer, it is possible to exhibit characteristics with high precision and excellent stability.

In addition, the mold can be released smoothly from the mandrill during cooling shrinkage, and electrodes for forming multi-electrode electric fields can be formed at the same time, resulting in high product yields, small dimensional errors, and precision manufacturing. The number of man-hours is also reduced, making mass production possible.

[Brief explanation of the drawing]

Figures 1 to 4 show examples of the present invention; Figure 1 is a cross-sectional view of a quadrupole electrode, Figure 2 is a perspective view of a mandrill, and Figure 3 is a process of forming a quadrupole electrode. FIG. 4 is a cross-sectional view for explaining the contracted state of the mold material, and FIG. 4 is a cross-sectional view of the structure in which the quadrupole electrode is attached. Further, FIGS. 5 and 6 show a conventional example, with FIG. 5 being a perspective view of a quadrupole electrode, and FIG. 6 being a sectional view of another quadrupole electrode. ■... Multipole electrode (quadrupole electrode), 2... Electrode, 4
... Electrode forming part, 6... Connection part, 10... Mandrill, 12... First mold material, 14... Second mold material.

Claims (3)

[Claims] (1) A multipolar structure in which a plurality of electrode forming parts provided with electrodes for forming a multipolar electric field and a connecting part that connects mutually adjacent parts of these electrode forming parts and maintains their positional relationship are integrally formed. A multipolar electrode, wherein the connecting portion is bulged outward away from a location where a multipolar electric field formed by the electrode is generated. (2) The first mold material for molding the connecting portion and the second mold material for molding the electrode forming portion according to claim 1 are combined together to form one mandrill, and a glass tube is placed on the mandrill and heated. A method for manufacturing a multipole electrode, characterized in that the softened glass tube is brought into close contact with a mandrill by evacuating the inside of the glass tube or pressurizing it from the outside, and after cooling, the mandrill is removed to form a multipolar electrode. (3) In the method for manufacturing a multipole electrode according to claim 2,
1. A method for manufacturing a multipole electrode, which comprises applying a conductive paste to predetermined locations inside a glass tube, and simultaneously forming electrodes by firing the conductive paste while heating the glass tube.