JPH02278641A - Cooling system for electron lens - Google Patents

Abstract

PURPOSE:To restrict drift by installing cooling pipes circularly in parallel in contact with the outer surface of a plurality of side plates. CONSTITUTION:A coil 1 has a cylindrical coil part 2, an inner cylinder 3 disposed on the inner circumferential surface of the coil part 2, and side plates 5a, 5b formed like flanges at both ends of the inner cylinder 3 for covering the side surface of the coil part 2. A cooling system is composed of cooling pipes 6a, 6b for cooling the coil 1, and a yoke 17 for covering the coil 1 and the cooling pipes 6a, 6b. The cooling pipes 6a, 6b are installed in parallel circularly in contact with the outer surface of the side plates 5a, 5b. The water permeation sectional area of the cooling pipes is thus made large, and the water quantity of cooling water can be increased, while heat radiation from the coil is facilitated because of a large water side heat transmission area. The coil attains a steady temperature in a short time, thereby waiting time by drift becomes short.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cooling system for an electron lens used in an electron microscope, an electron beam drawing device, an electron beam microanalyzer, and the like.

[Conventional technology]

The conventional technology will be explained using an example of an electron lens for an electron microscope, which is the main application of the present invention. A conventional electronic lens structure is shown in Japanese Utility Model Application Laid-Open No. 57-89256. This electronic lens generally consists of a cylindrical winding coil, a member that covers the coil, a cooling means that cools the coil, and a yoke that collectively covers the coil, the member that covers the coil, and the cooling means. The center hole of the donut-shaped yoke serves as a passage for the electron beam. An electron microscope stacks the above-mentioned electron lenses in multiple stages, energizes each coil to converge or expand the electron beam passing through the central axis, and
This allows samples to be observed at high magnification. When the coil is energized, the Joule heat of the coil heats and deforms the nearby parts of the device, distorting the image, so to prevent this, the coil is cooled. The cooling means is mainly determined by the amount of heat to be removed from the coil, and for electron microscopes with a heat radiation amount of about several tens of watts, water cooling is the mainstream. Water cooling means include a pipe method in which a cooling pipe is attached to a cooling plate that covers the coil, and a jacket method in which the cooling plate itself is processed to provide water passages. In either method, the Joule heat generated in the coil is transferred to the cooling water via a cooling plate, thereby performing cooling. Compared to the Jackera 1 method, the pipe method cannot provide a large amount of cooling water and a large heat transfer area on the water side, so it is disadvantageous in increasing the amount of heat dissipation.
Its advantages are that it has a simple structure and is easy to process, so it is widely used. As the field of use of electron microscopes expands, there is a desire for lower costs of the equipment. Along with this, patents have appeared that promote the advantages of the pipe method and reduce the cost. - For example, Japanese Patent Application Laid-open No. 5314/1983 discloses a method that greatly reduces machining by using sheet metal-processed inner cylinders and side plates, and caulking their joint surfaces.

[Problem to be solved by the invention]

In recent years, there has been a desire for the development of high-resolution electron microscopes, and as a result, the coil current of the electron lens tends to increase.However, in the conventional technology described above, the amount of heat dissipated from the coil increases due to the increase in coil current. However, sufficient consideration has not always been given to this.

In particular, when observing a sample at high magnification, image fluctuations such as drift and image pulsation, which will be described below, may become a problem in electron microscopes.

Drift 1- is a phenomenon in which the temperature of lens members such as coils and yokes changes over time, and the electron beam path moves due to thermal deformation of the lens members, making the image unstable. Drift disappears. However, it takes a long time for the temperature of the device to become steady, and a 1-lift is an undesirable phenomenon. Image pulsation is caused by fluctuations in water pressure from the outside propagated by the cooling water because cooling water is supplied from outside the device, and by vortices that occur in the part where the cooling water flow path inside the device contracts and expands. It is thought that this occurs because of In order to suppress the rise in coil temperature and reduce drift, the amount of cooling water must be increased. For this reason, if the cooling water main valve is opened further, the water pressure fluctuations propagating from the external piping will become even larger, causing the apparatus to vibrate and making the image more likely to vibrate. Conventionally, no consideration was given to attenuating water pressure fluctuations propagating from the external piping.

Furthermore, the shape of the flow channels within the device does not take into account the occurrence of local vortices, and when the amount of cooling water is increased, the image tends to pulsate due to fluid vibrations caused by the vortices.

The objects of the present invention are, firstly, to provide a cooling system that can suppress drift to a minimum by sufficiently cooling the coil even when the coil current is increased in an electronic lens; and secondly, to prevent fluctuations in the water pressure of the cooling water. It is an object of the present invention to provide a cooling system that can suppress image pulsation, and furthermore, to provide a cooling system for an electronic lens that is effective in reducing the size and weight of the electronic lens.

[Means to solve the problem]

The first purpose is to provide a cylindrical winding part, an inner cylinder disposed on the inner peripheral surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering the side surface of the winding part. In the cooling system for an electronic lens, the cooling pipe is configured to include a coil having a coil, a cooling pipe that cools the coil, and a yoke that covers the coil and the cooling pipe, in which a plurality of the cooling pipes are arranged in parallel in contact with the outer surface of the side plate. This is achieved by a cooling system for the electron lens, which is characterized by being attached in an annular manner.

It is preferable that the cooling water in the cooling pipe flows in the opposite direction to the cooling water in the cooling pipe adjacent to the cooling pipe, and the inner cylinder and the side plate are integrated by bending a single plate. It is preferable to manufacture it.

The first purpose is to provide a cylindrical winding part, an inner cylinder disposed on the inner circumferential surface of the winding part, and a brim-like shape formed at each end of the inner cylinder to cover the side surface of the winding part. In the electronic lens, the electron lens includes a coil having a side plate and an outer cylinder joined to the side plate and covering an outer peripheral surface of the coil, a cooling pipe that cools the coil, and a yoke that covers the coil and the cooling pipe. This is achieved by a cooling system for an electron lens characterized in that a plurality of pipes are wound in parallel around the outer cylinder.

The cooling water in the cooling pipe preferably flows in the opposite direction to the cooling water in the cooling pipe adjacent to the cooling pipe, and the side plate and the outer cylinder are joined by peeling or brazing. May be joined.

In addition, the above-mentioned first object includes a cylindrical winding part, an inner cylinder disposed on the inner peripheral surface of the winding part, and a collar-like shape formed at each end of the inner cylinder to cover the side surface of the winding part. a coil having a covering side plate;
In the cooling system for an electron lens, which is composed of a cooling pipe that cools the coil, and a yoke that covers the coil and the cooling pipe, the cooling pipe is attached to the outer surface of one of the side plates, and heat conduction is conducted to the outer surface of the cooling pipe. An electronic lens cooling system characterized in that a plate is attached and the heat conductive plate is pressed against the ceiling surface of the yoke via a vibration isolating member by a spring provided between the other side plate and the bottom surface of the yoke, achieved.

In order to conduct heat from the yoke to the cooling pipe,
The cooling pipe may be attached to the outer surface of one of the side plates, a heat conduction plate may be attached to the outer surface of the cooling pipe, and the heat conduction plate may be pressed against the bottom surface of the yoke via a vibration isolating member by the weight of the coil.

One method of manufacturing the coil is to fit two large and small coils concentrically.

The purpose of the above-mentioned miniaturization is to combine a cylindrical winding part, an inner cylinder disposed on the inner surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering the side surface of the winding part. In the cooling system for an electronic lens, the cooling pipe is installed in an annular shape on the outer surface of the side plate, and the cooling pipe is attached to the outer surface of the side plate. This can also be achieved by an electronic lens cooling system characterized by having joints for water supply and drainage installed in two places close to each other.

It is preferable that a current-carrying terminal connected to the coil be provided in a space between the joints provided at two locations or an extension space of the space, and on the outer surface of the side plate.

The second object is to provide a cylindrical winding section, an inner cylinder disposed on the inner surface of the winding section, and a side plate formed in a brim shape at each end of the inner cylinder and covering the side surface of the winding section. In the cooling system for an electronic lens, the cooling system includes a coil, a cooling pipe that cools the coil, and a yoke that covers the coil and the cooling pipe,
The cooling pipe is attached to the outer surface of the side plate in an annular manner, and the joint for supplying and draining water to the cooling pipe is attached to two adjacent places, and a smoothly curved pipe that is thinner than the cooling pipe is attached at least between the joint on the water supply side and the cooling pipe. This is achieved by an electron lens cooling system characterized by smooth connection with a connecting tube.

The second object is to provide a cylindrical winding part, an inner cylinder disposed on the inner surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering the side surface of the winding part. In the cooling system for an electronic lens, the two cooling pipes are attached to the outer surface of the side plate in an annular shape, and the two cooling pipes are annularly attached to the outer surface of the side plate. Attach joints for water supply and drainage to the main cooling pipe at two locations, provide a water chamber at least in the water supply joint, insert a connecting pipe in the form of a bent pipe into the water chamber, and connect one end of the connecting pipe to the water chamber for cooling. This can also be achieved by a cooling system for an electron lens, which is characterized by having its other end facing the water inlet and connected to the cooling pipe.

It is preferable that the connecting pipe is a tapered pipe whose diameter is narrow at the tip and reaches the diameter of the cooling pipe at the connecting portion of the cooling pipe.

If three or more of the cooling pipes are installed in a ring shape on the outer surface of the side plate, the ends of the three or more cooling pipes are evenly bundled and inserted into at least the water chamber in the water supply joint as a bundled pipe. However, it is preferable that the core of the bundled tube be sharpened so as to face the cooling water inlet of the water chamber.

The second object is to provide a cylindrical winding part, an inner cylinder disposed on the inner circumferential surface of the winding part, and a rib-like shape formed at each end of the inner cylinder to cover the side surface of the winding part. A cooling system for an electronic lens, which includes a coil having a side plate for covering the coil, a cooling pipe for cooling the coil, a yoke for covering the coil and the cooling pipe, and a water supply system upstream of the cooling system for the electronic lens; In the cooling system for an electronic lens which is combined with a drainage system on the downstream side, an absorber having an air tank is provided on the upstream side, and the absorber absorbs sudden water pressure fluctuations of the cooling water occurring in the water supply system. This is achieved by the characteristic cooling system of the electron lens.

The absorber includes a tank that stores air, a distributor provided under the tank that has a cooling water inlet and a plurality of outlets, and that distributes the cooling water to the electron lens. It is preferable to include a communication path that communicates with the head of the container.

[Effect]

In electronic lenses that have multiple cooling pipes attached to the side plate or outer cylinder of the coil, the water flow cross section of the cooling pipes has been increased, making it possible to increase the amount of cooling water and increasing the heat transfer area on the water side. Heat dissipation from strong recoil can be facilitated.

If the cooling water in adjacent cooling pipes flows in opposite directions, cold water and warm water will come into contact with each other.
The circumferential temperature distribution of the coil becomes uniform.

In an electronic lens that has an inner cylinder that covers the winding part of the coil and an outer cylinder on the side plate, a heat radiation path is formed from the coil to the cooling pipe via the side plate of the outer cylinder, and from the side plate away from the cooling pipe. A heat radiation path to the cooling pipe is formed through the outer cylinder and the side plate on the side of the cooling pipe, and the coil is uniformly cooled.

Further, in an electronic lens in which a cooling pipe is pressed against the inner wall of the yoke via a heat conduction plate and a vibration isolating member by a spring or its own weight, a heat conduction path is created between the cooling pipe and the yoke, and the yoke is cooled.

In addition, in an electronic lens using a coil formed by fitting two large and small coils into each other, the number of heat dissipation paths increases, and the temperature distribution of the coil becomes uniform.

In addition, in an electronic lens in which an energizing terminal for energizing the coil is attached to the outer surface of the side plate, the outer diameter of the coil is smaller than when the energizing terminal is provided on the outer periphery of the coil.

A water chamber is provided in the joint for supplying and draining water to the cooling pipe.
In an electronic lens, a thin, smoothly curved connecting pipe is inserted into the water chamber, one end of the connecting pipe faces the cooling water inlet, and the other end is connected to the cooling pipe. There are fewer collisions with the channel walls, and the vibration of the joint is reduced.

In addition, in the electronic lens cooling system, which consists of a combination of an electronic lens cooling system, an upstream water supply system for the cooling water, and a downstream drainage system, by providing an absorber with an air tank on the upstream side, the water supply It absorbs sudden pressure fluctuations in the cooling water that occur in the system and prevents pressure fluctuations from propagating to the electron lens cooling system.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 21.

1 and 2 are structural diagrams showing a first embodiment of an electron lens cooling system according to the present invention. Figure 1 is a cross-sectional view of the coil of the electron lens taken along the flow path of the cooling pipe that cools the coil (II cross section in Figure 2). It is a sectional view taken along ■-■ of the coil shown in FIG.

The coil 1 includes a winding part 2, an inner cylinder 3 that covers the inner surface of the winding part 2, an outer cylinder 4 that covers the outer surface, and side plates 5a and 5b that cover both sides.
, cooling vibros a and 6b are fixed in an annular manner over the entire surface by brazing on the outer surface of one side plate 5a, joints 7a and 7b for introducing cooling water into the cooling vibros a and 6b, and joints 7.
It consists of a current-carrying terminal 11 disposed between a and 7b for energizing the winding portion 2, and a resin 8 for fixing the current-carrying terminal 11 to the outer surface of the side plate 5a. The winding part 2 is hardened with resin to improve heat conduction between the windings, and is also made of an inner cylinder 3, an outer cylinder 4, and side plates 5a.
, 5b are made of a material with good thermal conductivity, and are in contact with the coil 1, respectively.

The coil 1 is surrounded by a donut-shaped yoke 17 on its inner circumferential surface, outer circumferential surface, and side surfaces, and the center hole of the donut-shaped yoke 17 serves as a passage through which the electron beam passes. Note that in FIG. 1, the illustration of the yoke is omitted so that the structure of the coil can be seen more clearly.

The first embodiment is related to drift reduction, and a plurality of cooling vibros a and 6b (only two are shown in FIG. 1, but three or more may be used) are connected to a joint 7 for supplying and discharging cooling water.
a, 7b, respectively, and partially intersect near the branching or merging points, so that the flow direction in at least one cooling pipe is opposite to that of the other cooling pipes, and cooling them. The pipes are fixed concentrically to the side plate 5.

The Joule heat generated in the winding section is transferred to the inner cylinder, which has good thermal conductivity.
Heat is radiated to the cooling water through the outer cylinder and side plate.

As the water temperature increases, the amount of heat dissipated varies locally, resulting in a temperature distribution in which the temperature of the side plate near the inlet side cooling pipe is low and the temperature of the side plate near the outlet side cooling pipe is high, which causes drift. In this embodiment, the flows in the cooling vibros a and 6b are rotated in opposite directions, so that the cold pipe on the inlet side and the warm pipe on the outlet side are constantly in contact along the circumferential direction of the side plate. Therefore, if the dimensions of the cooling pipe are appropriately selected, the temperature distribution on the side plate can be made small.

The energizing terminal 11 includes two independent water supply and drainage joints 7a,
It is fixed with resin 8 on the surface of side plate 5a in the space between 7b or an extension of the space. A lead wire coming from the winding portion 2 is connected to the current-carrying terminal 11 through a through hole provided in the side plate 5a, as shown in FIG.

The inner tube 3, the outer tube 4, and the side plates 5a and 5b are joined by a mechanical method such as caulking or by brazing with a bottom melting point metal. Conventionally, there have been some devices in which current-carrying terminals have been provided on the outer circumferential surface of the winding portion, and in that case, the outer circumferential surface has been hardened with a resin layer. In this embodiment, by using an outer cylinder made of a material with good thermal conductivity instead of the conventional resin layer, the cooling water in the cooling vibros a and 6b flows from the outer periphery of the winding part 2 to the outer cylinder 4 and through the side plate 5a. A heat dissipation path is formed. In addition, the side plate 5b, which is farthest from the cooling vibro and has traditionally been prone to high temperatures.
A heat radiation path is formed from near the outer periphery of the cooling water via the outer cylinder 4 and the side plate 5a on the cooling side to reach the cooling water.

By providing the outer cylinder as described above, it becomes possible to lower the outer peripheral temperature of the winding portion 2.

FIG. 4 is a plan view showing a portion of the cooling coil in accordance with the second embodiment of the present invention, and FIG. 5 is a view taken along arrows 1--2 in FIG. The second embodiment is for reducing drift, and as shown in the figure, two cooling vibros a are installed concentrically on the outer surface of the side plate 5a.

6b are joined, and joints 7a, 7b and 7c, 7d for water supply and drainage are attached to each end of the cooling vibros a and 6b, respectively. In the second embodiment, there is no intersection of the cooling pipes as shown in FIG.
By supplying water from the joints 7b and 7c and discharging water from the joints 7b and 7c, variations in the temperature of the side plate 5a can be reduced as in the first embodiment.

The configuration of the electron lens of the second embodiment is the same as that of the first embodiment except for the cooling pipe described above, so the explanation is omitted here.

FIG. 6 is a diagram showing a coil cooling pipe according to a third embodiment of the present invention. This embodiment suppresses drift, and the configuration of the electron lens is the same as that of the first embodiment except for the cooling pipe and the joint attached thereto. To avoid duplication, a description of its configuration will be omitted. In FIG. 6, two cooling vibros are connected in parallel to the outer cylinder 4 of the coil 1, and a joint 25 is attached to each of the cooling vibros. In other words, one joint 7 is used for water supply through a connecting pipe 25, and two cooling vibros are connected in parallel. At one end of each of the two cooling vibros, the other joint 7 is connected to the other end of each of the two cooling pipes via another connecting pipe 25 for drainage, so that the cooling water in each cooling pipe flows in opposite directions to each other. Flowingly connected.

By flowing the cooling water in the opposite direction in this manner, drift can be suppressed.

FIG. 7 is a longitudinal sectional view showing a fourth embodiment of the cooling system for an electron lens according to the present invention. A unique feature is that the inner cylinder surrounding the coil and the side plate are integrally machined from sheet metal, making it possible to ignore the thermal resistance at the joint between the inner cylinder and the side plate. Others are 1st
It has the same configuration as the electronic lens of the example. Therefore, the explanation of its configuration will be omitted. In FIG. 7, the bobbin 12, which is made up of an inner cylinder and a side plate, is formed by processing two thin plates into a U-shape.
Furthermore, it was rolled and finished into cylinders at both ends. However, it may also be manufactured by using two discs and a cylinder and completely joining their joining surfaces with molten metal or the like. After a cooling vibro is attached to the brim of this cylindrical cylinder, a coil is wound around the inner cylinder, and the outer cylinder 4 is joined. Furthermore, the winding portion 2 is impregnated with resin 8 for final finishing. Note that when performing roll finishing, the flange portions 12a corresponding to both side plates are easily stretched and deformed, and the width of the flange is subject to processing limitations. In this case, the sixth
As shown in the figure, a cylinder containing two or more large and small coils is manufactured using the above manufacturing method, excluding the cooling pipe installation.
Insert the cylinders with built-in coils into each other and temporarily assemble them together. Next, as shown in Fig. 1, a member in which only the joint 7 and the cooling pipe part are brazed is manufactured in advance, and as shown in Fig. 5, the member is placed on the side plate 5a and fixed with low melting point solder. 2 is impregnated with resin 8. In conventional technology, the jacket type has an integral structure made of cast metal, but the pipe type mainly involves cold working of metal plates, and the inner cylinder and both side plates have not been integrated. This is because the diameter of the coil was large, making it difficult to manufacture the flange.

However, in this embodiment, by increasing the coil current due to the improvement of the cooling effect, the coil diameter is reduced and the width of the ribs is reduced, making the above manufacturing method possible.

FIG. 8 is a diagram showing a fifth embodiment of the present invention, in which not only the coil but also the yoke are directly cooled with cooling water. The coil 1 has a structure similar to that shown in FIG. 1, but a side plate 5c having good thermal conductivity is joined to the yoke side plate 17a of the cooling vibro by brazing or the like. This coil 1
is the spring 2 via the elastic body 22 for vibration absorption.
3 is uniformly pressed against the lower surface of the yoke side plate 17a. With the above structure, the yoke side plate 17a and the coil 1
The side plates 5a of the yoke are thermally connected, and the yoke side plates 17a can be cooled by a cooling vibro. The thermal resistance between the yoke side plate 17a and the side plate 5a is determined by the pushing force of the spring 23, the thickness of the elastic body 22, the heat transfer area, and the thermal conductivity, but since the heat transfer area is large and can use the entire surface of the side plate, it is not a problem. Must not be.

The heat of the winding part 2 is transferred to the inner cylinder 3. In addition to being transmitted from the outer cylinder 4 etc. to the side plate 5a and reaching the cooling vibro, a small amount also reaches the yoke by radiation, convection, etc., raising the temperature of the yoke 17. In particular, the vicinity of the yoke side plate 17c is located on the side away from the cooling vibro, and the temperature tends to become high. According to this embodiment, since the yoke side plate 17a and the cooling vibro are thermally connected,
Yoke side plate 17c, yoke side plate 17b, and yoke side plate 1
A heat flow 7a is formed, making it possible to prevent the temperature of the yoke from rising due to heat leakage from the coil.

FIG. 9 is a sixth embodiment of the present invention, showing a modified type of the fifth embodiment. The coil 1 has the same structure as shown in FIG. 8, but the cooling vibro and the elastic body 22 are connected to the yoke 1.
Place it in contact with the yoke side plate 17c at the bottom of the coil 1, press the elastic body 22 with the weight of the coil 1, and press the elastic body 22 between the side plate 5a and the yoke side plate 17.
C is thermally connected.

Next, a seventh embodiment of an electronic lens cooling system having a structure for removing vibrations caused by cooling water and preventing image pulsation will be described. The seventh embodiment differs from the first embodiment in the structure of the cooling pipe and its joint, but is completely the same in other respects.

Therefore, only the cooling pipes and fittings will be described.

FIG. 10 is a cross-sectional view of the central axis of the cooling vibro of the seventh embodiment (X-X cross-sectional view of FIG. 11), and FIG.
This is a sectional view taken along line XI-X in the figure. A water chamber 24 having a dimension larger than the inner diameter of the water conduit pipe 9 through which cooling water is introduced or drained is provided in the joint 7 to which the two cooling vibros are connected, and one end of the water chamber 24 is connected to the cooling vibro. A connecting pipe 25 is inserted, which is smoothly connected to a and whose other end is narrowly bent.

Note that within the water chamber 24, the distal end of the communication pipe 25 and the distal end of the water guide pipe 24 are opposed to each other, and a suitable gap 26 is provided between the distal ends.

The amount of water flowing into each cooling vibro a, 6b is the gap 26
The size of the adjustment hole 27 partially opened in the communication pipe 25 is used to adjust the size. In addition, the bending radius of the communication pipe 25 is such that the direction of the jet flowing into the communication pipe 25 from the water conduit pipe 9 is gradually changed so that it does not collide with the inner wall of the communication pipe 25, so that the flow direction of the cooling water immediately before the cooling vibro a is set in the cooling pipe 25. Make it approximately coincide with the central axis.

Conventional joints are similar to those shown in Figure 1, without connecting pipes. Therefore, the flow path from the water conduit 9 to the cooling vibro a is curved at right angles, and includes a mixture of contraction and expansion portions. According to visual experiments, in the conventional joint, as shown in Fig. 21, when the jet flow A from the water conduit 9 collides with the joint inner wall 7c and the circulating flow B generated, mixes with the main flow C again, a violent vortex is induced. It was found that these vortices cause water pressure fluctuations and pulsating images. In the present invention, the above-mentioned communication pipe was devised based on the judgment that avoiding the jet flow from colliding with the inner wall of the joint is effective in suppressing image pulsation.

Next, an eighth embodiment will be shown in which the curved connecting pipe as described above is applied to a single wooden cooling pipe. In this embodiment, as shown in the cross-sectional view of the cooling pipe in FIG. 12, a tapered pipe 28 is inserted between the outlet (or inlet) of the joint 7 and the tip of the cooling vibro.

Further, in the ninth embodiment shown in FIG. 13, a thin and curved connecting pipe 28 is used between the joint 7 and the cooling vibro. In conventional inventions such as Japanese Utility Model Application Publication No. 57-89256, a tapered pipe is not used, but the cooling pipe is bent at right angles with a large bending radius. There is no difference between the seventh to ninth embodiments according to the present invention and the conventional example in that the jet flow from the joint inlet is smoothly bent. However, in this example, since a thin bent pipe and a tapered pipe are used, the bending radius can be made small and the rapid expansion of the water flow can be prevented.This has the advantage that when the coil diameter is small, the whole can be kept within the specified dimensions. be.

FIG. 14 is a plan view showing a tenth embodiment in which three cooling pipes are applied to the coil 1 of an electronic lens through a joint. The structure of the electron lens is the same as the first embodiment except for the joint and cooling pipe. In FIG. 14, each cooling vibro is assembled into a bundle at a branching and merging section to form an integrated communication pipe body 29.

In addition, as shown in the vertical cross-sectional view of the joint part in Fig. 15, a water chamber 24 larger than the inner diameter of the water conduit pipe 9 is provided in the joint 7, and the cooling water is branched or merged into a connecting pipe body with an acute angle at the tip. 2
The center of the pipe 9 is placed on the central axis of the water pipe 9. With the above structure, the cooling water jet from the water conduit 9 is directed to the connecting pipe body 2.
9 and enters each cooling pipe smoothly, the jets collide with only the wall 29a that partitions the communication pipe body 29, which is minimized, and fluid vibration can be reduced.

Next, a description will be given of an eleventh embodiment of the present invention, that is, a cooling system for an electronic lens provided with a device for absorbing fluctuations in water pressure of external cooling water.

FIG. 16 is a diagram showing an example in which this embodiment is applied to a transmission electron microscope. This electron lens cooling system is integrated with a cooling water supply valve 13, a distributor 30 that distributes the cooling water from the water supply valve 13 and supplies it to each electron lens 36 of the electron microscope, and a cooling water supply valve 13. It is comprised of an absorber 14 that absorbs water pressure fluctuations, a drain valve 16 that collectively discharges the cooling water discharged from the electron lens 36, and a tube 15 that connects these parts. When increasing the coil current, to keep the coil temperature constant and suppress drift,
Inevitably, it is necessary to increase the amount of cooling water, and the opening degree of the water supply valve 13 increases. As a result, a water pressure fluctuation component transmitted to the electron lens 36 by cooling water from outside the electron microscope device increases, causing the electron lens 36 to vibrate and making the image more likely to pulsate. In this embodiment, the absorber 14 absorbs fluctuations in water pressure entering the apparatus, and prevents the fluctuations from being transmitted to the electronic lens 36. Specifically, an air tank 18 as shown in FIGS. 17 and 18 is installed between each electronic lens 36 and the water supply valve 13 in FIG.
As shown in FIG. 9, the absorber 14 may be constituted by a riser pipe 32 having an air reservoir in the piping upstream from the branch section 31 to each electron lens.

In FIG. 17, the absorber 14 includes a distributor 30 having one inlet nozzle 20 for receiving cooling water from the water supply valve 13 and a plurality of outlet nozzles on one side for supplying the cooling water to each electron lens 36, and a distributor 30 for distributing the cooling water. Ceiling 30a of vessel 30
It consists of an air tank 18 placed on top of the air tank 18, and a communication pipe 19 that communicates the distributor 30 and the air tank 18.

FIG. 18 is a diagram showing an example in which the distributor 30 and the air tank 18 are integrated. A cylindrical tank is divided into two by a partition wall, the upper part serves as the air tank 18, and the lower part serves as the distributor 30. A small hole is made to connect the top and bottom.

In order to obtain high-resolution images, generally a closed loop is created that circulates between the chiller unit rat 33 and the electron microscope 34, as shown in FIG. 20, so that external water pressure fluctuations are not directly transmitted. The above absorber 14 is particularly effective in absorbing water pressure fluctuations of a specific wavelength that occur in the closed loop circulation pump 35.

However, even when the device is connected directly to the water supply, a significant effect can be seen by installing an absorber.

〔Effect of the invention〕

Since the present invention is configured as described above, it produces the effects described below.

In an electronic lens cooling system that consists of a coil that has a winding section, an inner cylinder that covers it, and a side plate, a cooling pipe for the coil, and a yoke, attaching multiple cooling pipes to the side plate may cause a break in the cooling water passage. The large area allows a large amount of cooling water to flow, improves heat dissipation from the coil, allows the coil to reach a steady temperature in a short time, and reduces waiting time due to drift. In addition, since the cooling water in adjacent cooling pipes flows in opposite directions to achieve uniform cooling, local thermal deformation of the coil is small, and images with small drift can be obtained once the quasi-steady temperature is reached. .

In addition, in the cooling system of an electronic lens, which is composed of a coil having a winding part, an inner cylinder covering it, a side plate, an outer cylinder, a cooling pipe for the coil, and a yoke, a plurality of cooling pipes are attached to the outer cylinder. In this case, as in the case where the cooling pipe is attached to the side plate as described above, the waiting time for drift can be reduced, and an image with small drift can be obtained. If an outer cylinder is provided, a heat conduction circuit is created between the inner cylinder, side plate, and outer cylinder, which improves heat radiation from the coil to the cooling pipe and reduces drift.

In the cooling system for an electronic lens, which consists of a coil having a winding section, an inner cylinder covering it, and a side plate, a cooling pipe for the coil, and a yoke, the cooling pipe attached to the side plate is connected to the inner surface of the yoke through a heat conduction plate. If the structure is such that the yoke is pressed against the yoke, it is easier to keep the temperature of the yoke constant and drift can be reduced.

Furthermore, in the cooling system of an electronic lens, which is composed of a coil having a winding part, an inner cylinder covering the winding part, and a side plate, a cooling pipe for the coil, and a yoke, a water chamber is provided at the joint of the cooling pipe attached to the side plate. A thin, smoothly curved connecting pipe is inserted into the water chamber, and the cooling water is passed through the connecting pipe to the cooling pipe, which reduces the chance of the cooling water colliding with the channel wall inside the joint. Image pulsation can be prevented.

Further, an absorber is provided upstream of the cooling system of the electronic lens, and the absorber attenuates rapid fluctuations in water pressure of the cooling water propagated from outside the apparatus, thereby preventing image pulsation.

By using the above-described structure for reducing image drift and the structure for preventing image pulsation together, it is possible to make the image of the electron lens clear.

Further, by increasing the cross-sectional area of the cooling pipe and improving the heat dissipation of the coil, the electronic lens can be made smaller and lighter.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the first embodiment of the cooling system for an electron lens according to the present invention, FIG. 2 is a cross-sectional view taken along the nm line in FIG. 1, and FIG. 4 is a plan view of the second embodiment of the present invention (cooling pipes in parallel), FIG. 5 is a view taken along the line V-V in FIG. 4, and FIG.
FIG. 7 is a vertical cross-sectional view of the fourth embodiment (large and small coils) of the present invention, and FIG. 8 is a diagram showing the fifth embodiment of the present invention
FIG. 9 is a vertical cross-sectional view of the embodiment (yoke cooling), FIG. 9 is a vertical cross-sectional view of the sixth embodiment (yoke cooling) of the present invention, and FIG. 10 is a cross-sectional view of the seventh embodiment (connecting pipe) of the present invention. , Figure 11 is the 10th
The XI-M sectional view in the figure and FIG. 12 are the eighth embodiment of the present invention (
FIG. 13 is a cross-sectional view of the ninth embodiment (bent connecting pipe) of the present invention, FIG. 14 is a plan view of the tenth embodiment (three cooling pipes), and FIG. The figure is an xv-xv cross-sectional view of Fig. 14, Fig. 16 is a diagram showing an example in which the electron lens cooling system is applied to an electron microscope, and Fig. 17゜18.19
20 is a diagram showing a closed loop of a cooling system of an electron microscope, and FIG. 21 is a schematic diagram showing vortex generation of cooling water in a conventional joint. ■... Coil, 2... Winding section, 3... Inner cylinder, 4...
Outer cylinder, 5... side plate, 6... cooling pipe, 7... joint,
14. Absorber, 17. Yoke, 18. Air tank, 19. Communication hole, 22.. Elastic body, 23.. Spring, 24. Water chamber, 36. Electronic lens.

Claims (1)

[Claims] 1. A cylindrical winding part, an inner cylinder disposed on the inner circumferential surface of the winding part, and a collar formed at each end of the inner cylinder to cover the side surface of the winding part. In the cooling system for an electronic lens, the cooling system includes a coil having a side plate, a cooling pipe that cools the coil, and a yoke that covers the coil and the cooling pipe. A cooling system for an electronic lens, which is characterized by being attached in a ring shape. 2. The cooling system for an electron lens according to claim 1, wherein the cooling water in the cooling pipe flows in the opposite direction to the cooling water in the cooling pipe adjacent to the cooling pipe. 3. The cooling system for an electronic lens according to claim 1, wherein the inner cylinder and the side plate are integrally manufactured from a single plate by bending. 4. A cylindrical winding part, an inner cylinder disposed on the inner circumferential surface of the winding part, a side plate formed in a brim shape at each end of the inner cylinder and covering a side surface of the winding part, and joined to the side plate. In the electron lens, a plurality of the cooling pipes are arranged in parallel, and includes a coil having an outer cylinder that covers the outer peripheral surface of the coil, a cooling pipe that cools the coil, and a yoke that covers the coil and the cooling pipe. An electronic lens cooling system characterized by being wrapped around an outer cylinder. 5. The cooling system for an electron lens according to claim 4, wherein the cooling water in the cooling pipe flows in the opposite direction to the cooling water in the cooling pipe adjacent to the cooling pipe. 6. The cooling system for an electronic lens according to claim 4, wherein the side plate and the outer cylinder are joined by caulking. 7. The cooling system for an electronic lens according to claim 4, wherein the side plate and the outer cylinder are joined by brazing. 8. A coil having a cylindrical winding part, an inner cylinder disposed on the inner peripheral surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering a side surface of the winding part. , in an electronic lens cooling system composed of a cooling pipe that cools the coil, and a yoke that covers the coil and the cooling pipe, the cooling pipe is attached to the outer surface of one of the side plates, and heat is applied to the outer surface of the cooling pipe. 1. A cooling system for an electronic lens, characterized in that a conductive plate is attached, and the heat conductive plate is pressed against the ceiling surface of the yoke via a vibration isolating member by a spring provided between the other side plate and the bottom surface of the yoke. 9. A coil having a cylindrical winding part, an inner cylinder disposed on the inner peripheral surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering a side surface of the winding part. , in an electronic lens cooling system composed of a cooling pipe that cools the coil, and a yoke that covers the coil and the cooling pipe, the cooling pipe is attached to the outer surface of one of the side plates, and heat is applied to the outer surface of the cooling pipe. 1. A cooling system for an electron lens, characterized in that a conductive plate is attached, and the heat conductive plate is pressed against the bottom surface of the yoke by the weight of the coil via a vibration isolating member. 10. A coil having a cylindrical winding part, an inner cylinder disposed on the inner peripheral surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering a side surface of the winding part. , an electronic lens cooling system comprising a cooling pipe that cools the coil, and a yoke that covers the coil and the cooling pipe, characterized in that the coil is formed by fitting two large and small coils concentrically. A cooling system for an electronic lens. 11. A coil having a cylindrical winding part, an inner cylinder disposed on the inner surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering a side surface of the winding part; In an electronic lens cooling system composed of a cooling pipe that cools a coil, and a yoke that covers the coil and the cooling pipe, a joint for attaching the cooling pipe in an annular shape to the outer surface of the side plate and for supplying and draining water to the cooling pipe. A cooling system for an electronic lens, characterized in that the lenses are mounted in two places close to each other. 12. The electronic lens according to claim 11, wherein a current-carrying terminal connected to the coil is provided in a space between the joints provided at two locations or an extension space of the space and on the outer surface of the side plate. cooling system. 13. A coil having a cylindrical winding part, an inner cylinder disposed on the inner surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering a side surface of the winding part; In an electronic lens cooling system composed of a cooling pipe that cools a coil, and a yoke that covers the coil and the cooling pipe, a joint for attaching the cooling pipe in an annular shape to the outer surface of the side plate and for supplying and draining water to the cooling pipe. Attach it to two places close to each other,
A cooling system for an electronic lens, characterized in that at least a joint on the water supply side and the cooling pipe are smoothly connected by a smoothly curved connecting pipe that is thinner than the cooling pipe. 14. A coil having a cylindrical winding part, an inner cylinder disposed on the inner surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering a side surface of the winding part; In an electronic lens cooling system comprising a cooling pipe that cools a coil, and a yoke that covers the coil and the cooling pipe, the two cooling pipes are attached to the outer surface of the side plate in an annular shape, and the two cooling pipes are connected to the cooling pipe. Attach joints for water supply and drainage at two locations, provide a water chamber at least in the water supply joint, insert a connecting pipe in the form of a bent pipe into the water chamber, and connect one end of the connecting pipe to the cooling water inlet of the water chamber. A cooling system for an electronic lens, characterized in that the opposite ends thereof are connected to the cooling pipe. 15. The cooling system for an electron lens according to claim 13 or 14, wherein the communication pipe is a tapered pipe whose diameter is narrow at a tip and becomes the diameter of the cooling pipe at a joint with the cooling pipe. 16. A coil having a cylindrical winding part, an inner cylinder disposed on the inner surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering a side surface of the winding part; In the cooling system for an electronic lens, the system includes a cooling pipe that cools a coil, and a yoke that covers the coil and the cooling pipe.
Attach fittings for water supply and drainage to the main cooling pipe in two places, provide a water chamber at least in the water supply fitting, and insert the ends of the three or more cooling pipes into the water chamber evenly together as a bundled pipe. A cooling system for an electronic lens, characterized in that the core of the bundled tube is sharpened and faces the cooling water inlet of the water chamber. 17. A coil having a cylindrical winding part, an inner cylinder disposed on the inner peripheral surface of the winding part, and a side plate formed in a brim shape at each end of the inner cylinder and covering a side surface of the winding part. , a cooling system for an electronic lens including a cooling pipe that cools the coil, a yoke that covers the coil and the cooling pipe, a water supply system on the upstream side of the cooling system for the electronic lens, and a drainage system on the downstream side. A cooling system for an electronic lens comprising: an absorber having an air tank on the upstream side; the absorber absorbs rapid water pressure fluctuations of the cooling water occurring in the water supply system; cooling system. 18. The absorber includes a tank storing air, a distributor provided under the tank and having a cooling water inlet and a plurality of outlets and distributing the cooling water to the electron lens, and the tank and the distributor. 18. The cooling system for an electronic lens according to claim 17, further comprising a communication path communicating with the head of the electronic lens.