JPH0747918Y2 - Clean magnetic field shield box - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a clean magnetic field shield box, and particularly for cooling a vibration-damping device placed on a vibration isolation base in a magnetic field shield box. The present invention relates to a clean magnetic field shield box that supplies clean air for dust removal.

[Conventional technology]

Conventionally, a clean magnetic field shield box of this type has a top opening 12 of a magnetic field shield box 10 as shown in FIG.
A filter unit 18 including a fan 14 and a high-performance filter 16 is provided in the. The filter unit 18 is for maintaining the cleanliness of the magnetic field shield box 10 and for preventing sound rise in the box 10 due to self-heating from the precision measuring device 20 which is a vibration-improving device installed in the box 10. Abbreviation
Clean air of 0.7 to 1.2 m / s is supplied into the box 10.

The precision measuring device 20 is mounted on a vibration isolation base 24 provided on the bottom surface 22 of the magnetic field shield box 10. The vibration isolation base 24 is a vibration isolation rubber 26 supported on the bottom surface 22,
An equipment mounting base 28 is mounted on the equipment mounting base 26, and the precision measuring equipment 22 is placed on the equipment mounting base 28. Therefore, the anti-vibration base isolation table 24 uses the anti-vibration rubber 2 to absorb the vibration propagated from the bottom surface 22.
By being attenuated by 6 and 26, it is possible to prevent vibration from propagating to the precision measuring device 22.

Further, exhaust ports 30, 30 are formed in the lower portion of the side surface of the magnetic field shield box 10. Therefore, the filter unit
The clean air supplied from 18 is blown toward the precision measuring device 20 as shown by the arrow and is exhausted to the outside of the magnetic field shield box 10 through the exhaust ports 30 and 30. Incidentally, since the precision measuring device 20 is often sensitive to a magnetic field and is also easily affected by microvibration, most of the precision measuring device 20 is mounted on the vibration isolation base 24 as described above. .

[Problems to be solved by the device]

However, in the conventional clean magnetic field shield box, since the clean air blown out from the filter unit 18 directly collides with the precision measuring device 22, vibration is generated in the precision measuring device 22 due to the impact of the collision, which causes the precision measuring device 22 to vibrate. 22 has the drawback of adversely affecting.

For example, the spring constant of the vibration isolation base 24 is set to 20 to 30 kg / cm which is usually applied, and the dynamic pressure due to the wind speed of 1 m / s is about 0.001 mm.
Assuming that a force of 1 g / m ² is applied to the vibration isolation base 24 as H ₂ O, the precision measuring device 22 will calculate about
Vibration of 0.5 μm will be generated. This level of vibration exceeds the permissible level in precision measuring instruments such as electron microscopes, and therefore adversely affects such precision measuring instruments.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a clean magnetic field shield box capable of preventing vibration of a vibration measuring device such as a precision measuring device caused by a collision of clean air. .

[Means for solving the problem]

The present invention provides an outer box (1
0) and an air supply port (12) opened on the upper surface of the outer box (10) to supply clean air into the outer box (10).
And an inner box (36) which is provided inside the outer box (10) and accommodates the vibration isolation device (20) placed on the vibration isolation base (24), and the upper surface of the inner box (36). And a ventilation port (38) formed to prevent the clean air from the air supply port (12) from being blown out toward the vibrating device (20) and the side surface of the inner box (36). And an exhaust port (40) for exhausting the air in the inner box (36) in a ventilation path (42) between the inner box (36) and the outer box (10).

[Action]

According to the present invention, clean air is blown toward the inside of the outer box (10) from the air supply port (12) opened on the upper surface of the outer box (10). A part of the blown clean air is blown into the inner box (36) from the ventilation hole (38) of the inner clean (36) without colliding with the vibration-damping device (20). As a result, since the clean air from the air source (18) does not directly collide with the vibrating device (20), it is possible to prevent vibration of the vibrating device (20) caused by the collision of the clean air.

In addition, the clean air blown into the inner box (36) is discharged into the air passage (4
It is attracted by the remaining clean air flowing in 2) and is exhausted from the exhaust port (40) formed in the lower side surface of the inner box (36).

〔Example〕

Hereinafter, preferred embodiments of a clean magnetic field shield box according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a sectional view showing an embodiment of a clean magnetic field shield box according to the present invention, and the same or similar members as those in the conventional example shown in FIG. .

In FIG. 1, the magnetic field shield box 10 is fixedly installed on a floor 32 of a factory or the like by a fixing jig (not shown).
Further, the magnetic field shield box 10 is formed of a high magnetic permeability material such as permalloy, electrolytic copper foil, electrolytic iron foil. Further, a cylindrical flange 34 is joined to the upper surface opening 12 of the magnetic field shield box 10. A filter unit 18 including a fan 14 and a high performance filter 16 is mounted in the flange 34. The high performance filter 16 is mounted flush with the top opening 12, and the fan 14 is mounted on the top of the high performance filter 16.
Is provided.

An inner box 36 is provided in the magnetic field shield box 10 to form a double box structure. The inner box 36 is made of a high magnetic permeability material like the magnetic field shield box 10. The precision measuring device 20 is placed on the vibration isolation base 24 within the inner box 36.

The vibration isolation base 24 is a multi-layered rubber 26, 26 supported on the bottom surface 22 in the inner box 36, and the multi-layered rubber 26,
It is composed of a device mounting base 28 mounted on 26. The multi-stage laminated rubber 26 is configured by alternately laminating a plurality of laminated rubbers and stabilizers, and the vibration propagated from the bottom surface 22 is absorbed by the laminated rubbers 26, 26 and propagated to the equipment mounting base 28. It is provided to prevent it.

On the other hand, on the upper surface of the inner box 32, a plurality of ventilation holes 3
8, 38 ... are formed. The ventilation holes 38, 38 ... Are connected to the precision measuring device 20 in the inner box 36 by the filter unit 18.
It is formed so as not to directly collide with clean air from. That is, the ventilation holes 38, 38 ... Are opened on the same circle on the upper surface of the inner box 36 in the direction of the inner side surface and at a left-right symmetrical angle of 45 °. Further, a plurality of exhaust holes 40, 40 ... Are formed on the side surface of the inner box 36. The exhaust hole 40,
40 are provided for discharging the clean air blown into the inner box 36 from the ventilation holes 38, 38 to the outside of the inner box 36. Further, the air exhausted from the exhaust holes 40, 40 ...
The magnetic field shield box 10 is attracted by the clean air passing through the ventilation passage 42 defined between
The gas is exhausted to the outside from exhaust ports 30 formed in the lower part of the side surface of the.

Next, the operation of the clean magnetic field shield box configured as described above will be described.

First, the fan 14 of the filter unit 18 is rotated to suck the outside air, and the outside air is passed through the high-performance filter 16 provided on the downstream side of the fan 14. As a result, the outside air is purified by removing dust in the outside air by the high-performance filter 16, and the magnetic field shield box as clean air.
It is supplied in the direction of the arrow in FIG.

Next, part of the supplied clean air is transferred to the inner box.
The air is blown from the ventilation holes 38, 38 of 36 toward the inner box 36. At this time, the clean air from the ventilation holes 38, 38 ... Is formed toward the inner surface of the inner box 36 without being directed to the precision measurement device 20, so that the precision measurement device 20 Do not directly collide with. by this,
Since the impact of the clean air collision is not applied to the precision measuring device 20, it is possible to prevent the vibration of the precision measuring device 20 caused by the impact of the clean air.

Further, the clean air from the ventilation holes 38, 38 ... Absorbs self-heating generated from the precision measuring device 20, and is further exhausted from the exhaust holes 40, 40 ... Together with dust generated in the inner box 36. At this time, the air exhausted from the exhaust holes 40, 40 ... Is attracted to the clean air passing through the ventilation paths 42, 42 in the direction of the arrow in the figure and exhausted to the outside from the exhaust ports 30, 30 of the magnetic field shield box 10. To be done. This allows the air in the inner box 36 to flow smoothly.

Therefore, according to the present embodiment, since the clean air is prevented from directly colliding with the precision measuring device 20 through the ventilation holes 38, 38 of the inner box 36, the conventional clean air which has collided the clean air with the precision measuring device is used. Compared with the magnetic field shield box, it is possible to prevent the vibration of the precision measuring device 20 caused by the collision of clean air. In addition, the cleanliness inside the inner box 36 can be maintained.
It is also possible to prevent the temperature rise in 36.

In the present embodiment, the exhaust port 30 of the magnetic field shield box 10,
Although it is supposed that the clean air after use is exhausted from 30, the suction fan is attached to the exhaust ports 30 and 30 and the suction fan is operated to more efficiently attract the air in the magnetic field shield box 10. it can.

Further, FIG. 2 shows an embodiment of a clean magnetic field shield box according to the present invention in which an electron microscope is installed. According to FIG. 2, the opening position of the upper surface opening portion 12 is formed at the same position as the taking-out position of the sample (wafer or the like) of the electron microscope. By using the clean magnetic field shield box according to the present invention for an electron microscope, the contamination of the sample wafer can be reduced. Further, since the inside of the clean magnetic field shield box can be maintained within the rated temperature, the operation rate of the electron microscope is improved and the work efficiency is also greatly improved.

[Effect of device]

As described above, according to the clean magnetic field shield box of the present invention, the inner box is provided inside the outer box, and the ventilation hole is provided on the upper surface of the inner box so as to prevent the clean air from being blown toward the vibrating device. Since it is formed, it is possible to prevent the vibration of the violating device caused by the impact of the clean air collision.

[Brief description of drawings]

1 is a sectional view showing an embodiment of a clean magnetic field shield box according to the present invention, FIG. 2 is a perspective view showing an embodiment of a clean magnetic field shield box according to the present invention for an electron microscope, and FIG. 3 is a conventional view. It is sectional drawing which shows the Example of a clean magnetic field shield box. 10 …… magnetic field shield box, 14 …… fan, 16 …… high-performance filter, 20 …… precision measuring equipment, 24 …… vibration isolation base, 30 …… exhaust port, 36 …… inner box, 38 …… Ventilation hole, 40 ... Exhaust hole, 42 ... Ventilation passage.

Claims (1)

[Scope of utility model registration request] 1. An outer box, an air supply opening which is opened on the upper surface of the outer box, and which supplies clean air into the outer box, and which is provided inside the outer box and mounted on a vibration isolation base. An inner box for accommodating the vibration-damping device, an air vent formed on the upper surface of the inner box so as not to blow clean air from the air supply port toward the vibration-damping device, and a side surface of the inner box. A clean magnetic field shield box, which is opened and has an exhaust port for exhausting air in the inner box to a ventilation path between the inner box and the outer box.