JPH0447890Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to an improvement in a gate valve that is effective for use in electron beam devices such as electron microscopes.

[Prior Art] In general, in electron beam devices such as electron microscopes, a gate valve is installed between the electron gun chamber and the mirror body in order to enable replacement of the filament without leaking the entire body. The electron gun chamber is configured so that it can be separated from the mirror body which is kept in a vacuum.

Gate valves used in such devices are designed to prevent vacuum leaks due to O-ring packing falling off due to sliding between the valve body and valve seat and damage to the contact surface between the valve body and valve seat when the valve body is opened and closed. must be prevented. Therefore, in the past, for example,
As in No. 45155, a shaped lever is rotatably installed directly under the valve seat that has an electron beam passage hole, and an O-ring packing is held between the lever and the valve seat so that it can move up and down on the piston shaft. At the same time, with the piston shaft in contact with the lever body, the lever body is rotated counterclockwise by further moving the piston shaft, and the lock plate is pressed against the valve seat. A new structure has been proposed.

[Problems to be Solved by the Invention] With this configuration, the valve body and the lock plate will not slip against each other, and it is possible to prevent the O-ring packing from falling off. however,
On the other hand, a letter-shaped lever body that is asymmetrical with respect to the optical axis of the electron beam must be placed on the electron beam path. Therefore, even if the lever body is made of a non-magnetic material, it may have an adverse effect on the electron beam, distorting the shape of the beam or improperly deflecting the beam, leading to a decrease in resolution.

An object of the present invention is to provide a gate valve that can solve these drawbacks.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a valve seat having a plane perpendicular to the electron beam passage hole and a side surface substantially perpendicular to this plane, and a valve seat that is closely attached to the valve seat. a valve body having an O-ring packing for blocking the hole, an L-shaped lever body rotatably supporting the valve body at one end, and a substantially middle portion of the lever body rotatable. and a driving means for reciprocating the moving shaft, and when the valve body is placed in a position facing the hole in the valve seat due to the movement of the moving shaft, the other end of the lever body The valve body is characterized in that it is configured to press the valve body against the valve seat by abutting against the side surface of the valve seat and rotating this lever body.

[Embodiment] FIG. 1 is a sectional view showing an embodiment of the present invention, and 1 is a mirror body of an electron microscope. 2 is a hole for electron beam passage formed in the center of this mirror; 3 is a valve seat; this valve seat has a plane 4 perpendicular to the hole 2 and a side surface 5 perpendicular to the plane; are doing.
Reference numeral 6 denotes a lever body formed in an L-shape, the middle part of which is rotatably held at the tip of a moving shaft 8 via a pin 7. Also. A ball 9 is installed on the lower surface of one end (point of action) of this lever body 6, and
As shown in the side view of FIG. 2, when the valve body 10 is in contact with this ball, the two springs 11
a, 11b. Furthermore, a ball 12 is also implanted at the other end (force point) of this lever body 6. In order to support the valve body 10 on the lever body 6, a recess 13 is formed on the valve body side, and the lever body is movably fitted into this recess, so that the valve body can be moved left and right with respect to the lever body. It is designed so that it does not deviate from the direction. 14 is O for the vacuum seal attached to the valve body 10.
It's ring patsuking. The moving axis 8 is the mirror body 1
The side wall of the air cylinder 15 is slidably penetrated in an airtight manner, and its tip is connected to a piston in the air cylinder 15.

Reference numeral 16 denotes a leaf spring fixed to the part of the moving shaft 8 where the valve body 10 is attached. I am accomplishing it. Also,
The upper end portion C of this leaf spring 16 is bent in the horizontal direction, and also serves as a stopper for regulating the rotation angle of the lever body 6.

17a and 17b are lever bodies 6 as shown in FIG.
This is a guide block for guiding the movement of this lever body by holding both sides of the lever body on the side of the force point.

Now, when the valve body 10 is separated from the optical axis Z of the electron beam, the action point side of the lever body 6 is pushed up by the leaf spring 16, and the valve body 10 is pushed up against the valve seat 3 as shown in FIG. It is located above the horizontal plane 4 of . Then, the air cylinder 15 is driven to move the moving shaft 8 toward the electron beam optical axis Z side, and the first
When the valve body 10 is located directly above the hole 2 as shown in the figure, the ball 12 provided on the side of the force point of the lever body 6 comes into contact with the side surface 5 of the valve seat. In this state, if the moving shaft 8 is further moved in the same direction,
Since a rotational force is generated in the lever body 6 in a counterclockwise direction (a direction that resists the pressing force of the leaf spring 16), the action point side of the lever body is pushed down, and the valve body 10 is pushed down as shown in FIG. is pressed against the flat surface 4 of the valve seat 3, and the electron beam passage hole 2 is closed.

Next, when moving the moving shaft 8 from the state shown in FIG. is released, the lever body 6 is rotated clockwise by the leaf spring 16. As a result, the valve body 10 is pulled upward and separated from the valve seat 3 without sliding on the horizontal surface 4 of the valve seat 3. When the lever body 6 comes into contact with the upper end portion C of the leaf spring 16, as shown in FIG. It is removed from the shaft Z portion, and the electron beam passage hole is completely opened.

In the above description, the case where the valve body is pressed against the valve seat from above has been described, but the case where the valve body is pressed against the valve seat from below can also be implemented in the same manner. In this case, the weight of the valve body and the lever body constantly applies a rotational force to the lever body in the direction of separating the valve body from the valve seat, so the plate is It is not necessary to use the spring to apply a rotational force to the lever body in the direction of separating the valve body from the valve seat.

[Effect of the invention] By doing the above, there is no need to install a lever body on the electron beam passage as in the past to press the valve body placed opposite the valve seat against the valve seat. . As a result, it is possible to prevent the beam shape from being distorted and the beam from being improperly deflected, thereby preventing a decrease in resolution.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing one embodiment of the present invention;
The figure is a sectional view of AA in figure 1, and figure 3 is BB of figure 1.
The cross-sectional view and FIG. 4 are diagrams for explaining the operation. 1... Mirror body, 2... Hole for electron beam passage, 3... Valve seat, 4... Plane, 5... Side surface, 6... Lever body, 7
...Pin, 8...Movement axis, 9,12...Ball,
10... Valve body, 11a, 11b... Spring,
13... recess, 14... O-ring packing, 1
5... Air cylinder, 16... Leaf spring, 17
a, 17b...Guide block.

Claims (1)

[Scope of utility model registration request] a valve seat having a plane perpendicular to the electron beam passage hole and a side surface substantially perpendicular to the plane; a valve body having an O-ring packing for blocking the hole by being brought into close contact with the valve seat; one end; an L-shaped lever body rotatably supporting the valve body, a moving shaft rotatably holding a substantially middle portion of the lever body, and a driving means for reciprocating the moving shaft. When the valve body is placed in a position facing the hole in the valve seat due to the movement of the moving shaft, the other end of the lever body comes into contact with the side surface of the valve seat, and this lever body rotates, thereby pushing the valve body into the valve position. A gate valve in an electron beam device configured to press against a flat surface of a seat.