Vacuum sealing cap

Abstract

To provide a vacuum sealing valve capable of air-tightly sealing an opening portion.SOLUTION: A vacuum sealing valve is provided, which is equipped with a valve body 75 sealing / releasing the sealing of an opening portion 107 formed on a wall body 106, a shaft member 71 capable of moving forward / backward generally in parallel with the wall body, a link 74 connecting the valve body and the shaft member so as to displace with each other, a conversion mechanism 84 converting the forward / backward movement of the shaft member into the movement in an opening portion direction of the valve body, and rollers 82 and 83 disposed at positions opposite to the opening portion across the shaft member, abutting on the shaft member in a sealing state of the valve body, and suppressing deformation of the shaft member. The deformation of the shaft member due to reaction force applied on the valve body is suppressed by the rollers, and an inclination of the valve body due to the deformation is also suppressed, so that the valve body is uniformly pressed to air-tightly seal the opening portion.SELECTED DRAWING: Figure 8

Description

[Technical field]

[0001] The present invention relates to a vacuum seal valve that opens and closes an opening provided in a partition wall that separates a vacuum chamber. [Background technology]

[0002] 2. Description of the Related Art Devices having a vacuum chamber, such as electron microscopes, are provided with a partition wall for dividing the interior of the vacuum chamber, and a vacuum seal valve for sealing an opening provided in the partition wall.

[0003] For example, Patent Document 1 discloses a gate valve (vacuum sealing valve) that includes a valve body with an O-ring for air-tightly sealing an opening, a base body that holds the valve body via a link mechanism, and a shaft member that is connected to one end of the base body and moves the base. When the shaft member is moved forward, the valve body comes into contact with a stopper provided in the vacuum chamber, and the movement of the valve body is restricted and the valve body moves toward the opening, air-tightly sealing the opening. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP2001-324032A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned Patent Document 1, there is a problem in that the shaft member escapes in the direction opposite to the opening before the O-ring is crushed, making it impossible to achieve airtight sealing.

[0006] The present invention has been made in consideration of the above problems, and provides a vacuum seal valve that reliably opens and closes an opening. [Means for solving the problem]

[0007] In order to achieve the above-mentioned object, in one aspect of the configuration of the present disclosure, a vacuum sealing valve is provided that includes a valve body that seals / unseals an opening formed in a wall body, a shaft member that can move back and forth approximately parallel to the wall body, a link mechanism that displaceably connects the valve body and the shaft member to each other, a conversion mechanism that converts the forward and backward movement of the shaft member into movement of the valve body toward the opening via the link mechanism, and a roller that is positioned opposite the opening across the shaft member, and abuts against the shaft member when the valve body is sealed, thereby suppressing deformation of the shaft member.

[0008] According to this aspect, when sealing the opening, the shaft member can be prevented from warping upward due to the reaction force received by the valve body by the roller abutting against the shaft member. Therefore, it is possible to prevent a decrease in sealing force due to warping of the shaft member, and the valve body can reliably seal the opening.

[0009] In one embodiment, at least two rollers are provided, and one or more rollers are arranged on each of the base end side and the tip end side of the shaft member with respect to the opening. According to this embodiment, since the reaction force is directed toward the upper part of the opening, by arranging two rollers on either side of the opening, it is possible to reliably suppress warping of the shaft member and increase the sealing force of the valve body.

[0010] In one embodiment, the valve body and the shaft member are configured to have holes formed therein that are aligned with the opening when the valve body is in an unsealed state. When the opening is in an open state, a path through the opening is secured. The valve body that closes the opening only needs to move slightly from an open state to a closed state, which reduces metal sliding and reduces particle generation.

[0011] In one embodiment, the conversion mechanism is a second roller that contacts an inclined surface provided at the tip of the valve body, and the second roller is configured to be arranged in a position approximately directly opposite the roller with the shaft member sandwiched therebetween, and slightly spaced from the shaft member. According to this embodiment, the two rollers are configured to sandwich the shaft member. In a normal state, the roller and the shaft member are slightly spaced apart, so no particles are generated due to the sliding between them, and even if they come into contact, the contact area is small because they are rollers, and sliding is minimized by rotation. Effect of the Invention

[0012] According to the above configuration, it is possible to provide a vacuum seal valve that reliably opens and closes the opening. [Brief description of the drawings]

[0013] [Figure 1] 1 is a schematic diagram of an electron microscope equipped with a vacuum sealing valve according to an embodiment of the present invention. [Diagram 2] FIG. [Diagram 3] FIG. 2 is a side view of the vacuum seal valve (some components are not shown for the purpose of illustration). [Figure 4] FIG. 2 is a vertical cross-sectional view of the vacuum seal valve. [Diagram 5] FIG. [Figure 6] 11A and 11B are explanatory diagrams for explaining the effect of a connection mechanism. [Figure 7] 11A and 11B are explanatory diagrams for explaining the effect of a connection mechanism. [Figure 8] FIG. [Figure 9] 1A and 1B are explanatory diagrams of the open and closed states of the opening and closing mechanism, in which (A) shows the open state (unsealed state) and (B) shows the closed state (sealed state). [Figure 10] This is a modified example, which corresponds to FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] (Electron Microscope 100) DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present disclosure will now be described with reference to the accompanying drawings. Fig. 1 is a schematic diagram of an electron microscope 100 equipped with a vacuum seal valve 1 according to an embodiment.

[0015] As shown in FIG. 1, the electron microscope 100 includes an electron gun 101, an electron beam control mechanism 102 consisting of a lens mechanism for focusing the electron beam EB emitted from the electron gun 101 on a predetermined portion of a sample W and a scanning mechanism for scanning the electron beam EB, and a lens barrel 103 having the electron gun 101 and the electron beam control mechanism 102 inside.

[0016] The electron microscope 100 is a scanning electron microscope (SEM) that detects secondary electrons and the like generated by irradiating a sample W with an electron beam EB emitted from an electron gun 101, and displays a sample image based on this detection signal in synchronization with two-dimensional scanning of the electron beam EB on the sample W. The configuration of the present disclosure is not limited to application to the electron microscope 100, but is also suitable for a transmission electron microscope (TEM) that irradiates the sample W with an electron beam EB and magnifies and observes the electrons that have passed through it, a wire lithography apparatus, an electron beam exposure apparatus, and the like. Also, an ion gun may be used instead of the electron gun 101 to irradiate an ion beam.

[0017] The column 103 has therein an electron gun chamber 104 that houses the electron gun 101, a control mechanism chamber 105 that houses the electron beam control mechanism 102, and a partition wall 106 that separates them. The partition wall 106 has an opening 107 that connects the electron gun chamber 104 and the control mechanism chamber 105. Due to the characteristics of the electron microscope 100, the electron gun chamber 104 is evacuated to a vacuum (10 -5 Ultra-high vacuum of 10 Pa or less -8 The control mechanism chamber 105 is also evacuated to a vacuum by a vacuum exhaust mechanism 108B.

[0018] The electron microscope 100 is equipped with a vacuum seal valve 1 as a mechanism for sealing / unsealing (hereinafter referred to as opening and closing) the opening 107. The vacuum seal valve 1 is supported by passing through a through hole 109 provided in a side wall 103a of the microscope column 103 that is approximately perpendicular to the partition wall 106. Since it takes time to evacuate the electron microscope 100, when repairing the electron gun 101 or replacing the sample W, the vacuum seal valve 1 is used to maintain the electron gun chamber 104 or the control mechanism chamber 105 at a vacuum. In addition, when the electron microscope 100 is transported, the opening 107 is sealed by the vacuum seal valve 1 before transport.

[0019] (Vacuum sealing valve 1) The vacuum seal valve 1 will be described in detail with reference to Figs. 2 to 4. Fig. 2 is a perspective view of the vacuum seal valve 1. Fig. 3 is a side view of the vacuum seal valve 1. Fig. 4 is a vertical cross-sectional view of the vacuum seal valve 1. In Fig. 3, some components are omitted for ease of explanation.

[0020] As shown in Figures 2 to 4, the vacuum sealing valve 1 is provided with an opening / closing mechanism 2 at its tip for opening and closing an opening 107. The opening / closing mechanism 2 is composed of a moving side mechanism 7 and a fixed side mechanism 8 fixed to a partition wall 106. The moving side mechanism 7 of the opening / closing mechanism 2 is connected to a bellows 4 via a connection mechanism 3, and the bellows 4 is connected to an actuator 6 via a fixed portion 5.

[0021] The actuator 6 is a drive source for the vacuum seal valve 1. When the actuator 6 moves back and forth substantially parallel to the partition wall 106, this movement is transmitted to the opening and closing mechanism 2, and the opening and closing mechanism 2 converts the forward and backward movement of the actuator 6 into a motion for opening and closing the opening 107, thereby opening and closing the opening 107.

[0022] In this embodiment, a double-acting air cylinder is used for the actuator 6. A retractable single-acting air cylinder may be used, and when the electron gun 101 is not in use, the cylinder is maintained in an advanced state by the bias of a compression spring or the like to keep the opening / closing mechanism 2 in a closed state, and only when the electron gun 101 is in use, the cylinder is moved backwards by air pressure to open the opening / closing mechanism 2. The bias of the compression spring makes it easy to maintain the opening / closing mechanism 2 in a closed state. The actuator 6 is not limited to this, and a known driving mechanism may be used.

[0023] As shown in Fig. 4, the bellows 4 is provided so as to cover the periphery of a transmission shaft 41 disposed inside. The transmission shaft 41 is connected to the actuator 6 via a connection shaft 42. An end of the bellows 4 is fixed to the surface of the fixed part 5, and the internal space of the bellows 4 communicates with an internal space 51 provided in the fixed part 5. In this communicated internal space, the transmission shaft 41 moves forward and backward integrally with the actuator 6. By using the bellows 4, it is possible to obtain power from the actuator 6 located outside the electron gun chamber 104 (on the atmospheric side) and move the transmission shaft 41 forward and backward while maintaining the vacuum atmosphere of the electron gun chamber 104.

[0024] The transmission shaft 41 is connected to a main shaft 71 that constitutes the moving side mechanism 7 of the opening / closing mechanism 2 via the connection mechanism 3, and as these move together, the forward and backward movement of the actuator 6 is transmitted to the opening / closing mechanism 2.

[0025] (Connection mechanism 3) The connection mechanism 3 that connects the transmission shaft 41 and the main shaft 71 will be described in detail. Fig. 5 is an exploded perspective view of the connection mechanism 3. In the description, the direction in which the transmission shaft 41 is arranged is the rear, and the direction in which the main shaft 71 is arranged is the front.

[0026] As shown in FIG. 5, the connection mechanism 3 includes a first connection member 31, a second connection member 32, and a headless bolt 34 in addition to the transmission shaft 41 and main shaft 71 that are connected.

[0027] From the front, the main shaft 71, the second connecting member 32, the first connecting member 31, and the transmission shaft 41 are arranged in this order with their axes aligned in the front-to-rear direction.

[0028] The transmission shaft 41 is a long, thin rod-like body, and is provided with a disk-shaped first flange portion 41a on the front side where it is connected to the main shaft 71. The bellows 4 is welded to the rear surface of the first flange portion 41a (see FIG. 4).

[0029] A column 41b protrudes forward from the first flange 41a, and a disk-shaped second flange 41c is provided at the tip of the column 41b. The second flange 41c has two through holes 41d that penetrate it, and the bolts 33 are inserted through these through holes and screwed into the screw holes 31b provided in the first connecting member 31, thereby fastening the transmission shaft 41 to the first connecting member 31.

[0030] A circular recess 41e is provided in the center of the front surface of the second flange portion 41c, and the circular protrusion 31a protruding from the center of the rear surface of the first connecting member 31 engages with this to assist in fastening.

[0031] A female screw portion 31d is provided as a screw hole in the center of the front surface of the first connecting member 31 having a cylindrical shape. A male screw portion 32a protruding from the center of the back surface of the second connecting member 32 is screwed into this female screw portion 31d. The female screw portion 31d and the male screw portion 32a are for adjusting the position of the main shaft 71 in the front-rear direction, and the position of the main shaft 71 can be adjusted in the front-rear direction by the thread length of the male screw portion 32a.

[0032] After the second connecting member 32 is screwed into the first connecting member 31 and the positioning of the main shaft 71 in the front-rear direction is adjusted, the headless bolt 34 is inserted into the insertion hole 32c provided in the second connecting member 32 and screwed into the screw hole 31c provided in the first connecting member 31. As a result, the tip end 34a of the headless bolt 34 is fixed to the first connecting member 31, and the rear end 34b protrudes from the surface of the first connecting member 31 and is positioned in the insertion hole 32c of the second connecting member 32. The size of the headless bolt 34, more specifically, the rear end 34b, is set so that there is a slight gap between the inner wall of the insertion hole 32c and the headless bolt 34.

[0033] The insertion hole 32c is formed at a position communicating with the screw hole 31c, and the second connecting member 32 has a plurality of insertion holes 32c on the same circle centered on the screw-engagement axis of the female screw portion 31d and the male screw portion 32a.

[0034] Meanwhile, a flange portion 71a is also formed at the rear end of the main shaft 71, and the bolt 35 is inserted through two insertion holes 71b formed in the flange portion 71a and screwed into a screw hole 32b provided in the front surface of the second connecting member 32, thereby fastening the main shaft 71 to the second connecting member 32. In this way, the main shaft 71 and the transmission shaft 41 are connected via the connecting mechanism 3.

[0035] (Function and effect of connection mechanism 3) The connection mechanism 3 having such a configuration has three operational effects. The first is, as described above, the arrangement of the main shaft 71 can be adjusted.

[0036] Although the details will be described later, the main shaft 71 is provided with a through hole 71c for passing the electron beam EB, and in order to ensure a path (beam path) of the electron beam EB when the opening / closing mechanism 2 is in an open state, this through hole 71c needs to be arranged on approximately the same vertical line as the opening 107. Such a requirement for high accuracy in arrangement can be met by adjusting the connection length using the connection mechanism 3. Since the connection length is adjusted by screwing, a configuration in which the male thread portion and the female thread portion are provided inversely may also be used.

[0037] The insertion holes 32c are provided at two opposing positions, and either of the insertion holes 32c may be used when screwing in the headless bolt 34 after the length adjustment. Since the second connecting member 32 is configured so that its rotation can be stopped by the headless bolt 34 every half rotation, the connection length can be finely adjusted in units of the length of half a thread of the male screw portion 32a.

[0038] The second is to absorb damage caused by the circumferential movement of the bellows 4. The headless bolt 34 protrudes from the first connecting member 31 and is disposed in the insertion hole 32c. The diameter of the insertion hole 32c is slightly larger than the diameter of the headless bolt 34, and since no lock nut or the like is used for the headless bolt 34, the second connecting member 32 can rotate by the difference in diameter. In other words, the main shaft 71 and the transmission shaft 41 can rotate slightly in the circumferential direction even after their lengths are adjusted and they are connected.

[0039] The bellows 4 is a kind of spring structure made by welding metal plates, and it contracts to follow the axial movement of the transmission shaft 41 to which it is fixed. However, it cannot move at all in the circumferential direction, and so when the transmission shaft 41 fixed to the bellows 4 makes even the slightest rotational movement, excessive stress is applied to the bellows 4, which may cause the bellows 4 to break. For example, even if a slight twist occurs in the circumferential direction during the opening and closing movement by the opening and closing mechanism 2 and is transmitted to the main shaft 71 as a rotational movement, the second connecting member 32 rotates to absorb this, thereby reducing the rotational load on the bellows 4.

[0040] If the main shaft and the transmission shaft are completely fixed using a lock nut or the like after the position is adjusted by screwing in the conventional configuration, even the slightest rotation of the opening and closing mechanism is directly transmitted to the transmission shaft, causing the problem that the bellows connected to the transmission shaft is destroyed by the rotation load. On the other hand, if the position is only adjusted by screwing in and there is no rotation prevention at all, the screwing will loosen due to sliding during opening and closing, causing a problem that the connection length and connection angle will change.

[0041] In this embodiment, the headless bolt 34 is used to prevent rotation, while a gap is provided in the insertion hole 32c through which the headless bolt 34 is inserted, leaving a small amount of room for the first connection member 31 to rotate. As a result, the rotation of the main shaft 71 is absorbed by the amount of this gap, and the rotation transmitted to the bellows 4 is reduced. By configuring the connection mechanism 3 as described above, damage caused by the circumferential movement of the bellows 4 is absorbed. Furthermore, the rotation of the main shaft 71 makes it possible to suppress imbalance in the sealing force.

[0042] In this embodiment, the second connecting member 32 is made of steel such as stainless steel, and the first connecting member 31 is made of a metal such as beryllium copper that is softer than the components of the second connecting member 32. By using different metals, friction on the sliding surfaces of the screwed parts is reduced, making them easier to slide (rotate). Furthermore, by making the female threaded part 31d out of a metal softer than the male threaded part 32a, the female threaded part 31d is scraped off during slippage, reducing friction during slippage. This makes it easier for the second connecting member 32 and the first connecting member 31 to rotate, and the rotation load on the bellows 4 can be reduced.

[0043] The third effect is the correction of the circumferential deviation of the main shaft 71 from the normal position that occurs when the fixed part 5 is fixed to the lens barrel 103. This will be explained with reference to Figs. 6 and 7. Fig. 6 shows the fastened state of the fixed part 5 and the lens barrel 103, as seen from the direction of the arrow A in Fig. 3. It is a schematic diagram showing the relative arrangement of the lens barrel 103 and the fixed part 5, and the fixing bolt is omitted. Figs. 6(A) and 6(B) show the state in which the fixed part 5 is fixed to the lens barrel 103 in the normal position. Fig. 6(C) shows the state in which the fixed part 5 is fastened to the lens barrel 103 while tilting counterclockwise from the normal position. Fig. 6(D) shows the state in which the fixed part 5 is fastened to the lens barrel 103 while tilting clockwise from the normal position.

[0044] The vacuum seal valve 1 is fixed to the flange of the through hole 109 by the fixing part 5 with a screw (see FIG. 3). As shown in FIG. 6, the lens barrel 103 is provided with six screw holes 103b arranged at equal angles in a circular ring shape for fastening the fixing part 5. The fixing part 5 to be fixed is provided with six screw insertion holes 52 arranged at equal intervals in a circular ring shape corresponding to the screw holes 103b. However, in order to absorb the formation error of the screw holes 103b and to reliably fasten the fixing part 5, the hole diameter of the screw insertion holes 52 needs to be larger than the diameter of the screw holes 103b, and the fixing part 5 may be attached at a slight circumferential inclination from the correct position by the difference in diameter.

[0045] As shown in Fig. 6(C), there is a possibility that the fixing part 5 may be attached tilted counterclockwise by a maximum angle of -α from the normal position, centered on the mounting center O of the fixing part 5. Also, as shown in Fig. 6(D), there is a possibility that the fixing part 5 may be attached tilted clockwise by a maximum angle of +α, centered on the mounting center O. Here, the angle ±α is the mounting play angle calculated from the difference in diameter between the screw hole 103b and the screw insertion hole 52.

[0046] Even if the fixing part 5 is attached at an angle α, the connecting mechanism 3 rotates so that the connected main shaft 71 is brought to the correct horizontal position and maintained in this state. In this way, the headless bolt 34 and the insertion hole 32c not only serve to stop the rotation of the second connecting member 32 after the length adjustment, but also serve to fine-tune the circumferential direction. The arrangement and diameter of the headless bolt 34 and the insertion hole 32c determine the relative rotatable angle between the main shaft 71 and the transmission shaft 41. It is preferable that this rotatable angle be equal to or greater than 2α.

[0047] In the case of the conventional configuration where there is no connection mechanism 3 and the main shaft and the transmission shaft are completely fixed, if the vacuum sealing valve is attached to the lens barrel at an angle α, the main shaft will also be tilted at the angle α from the horizontal, and the valve body will seal the opening at an angle α.

[0048] The difference between this embodiment and the conventional configuration will be described with reference to Fig. 7. Fig. 7 is a view of the opening and closing mechanism 2 as seen from the front. It shows a state in which the fixed part 5 is fixed in the correct position. The O-ring 76 is a sealant that seals the opening 107. The O-ring 176 shown by the two-dot chain imaginary line is a sealant in a conventional configuration without the connection mechanism 3, shown for comparison, and shows a state in which it is attached at an angle α with the mounting center O of the fixed part as the center.

[0049] In a conventional vacuum sealing valve in which the opening / closing mechanism and the actuator are completely integrated in the circumferential direction, when the valve is attached to the housing at an angle α in the circumferential direction, the opening / closing mechanism is also tilted at the angle α in the circumferential direction. That is, the O-ring 176 that seals the opening is also tilted at the angle α around the attachment center. The amount of crushing of the O-ring 176 is reduced by the height difference H of the O-ring 176 in this tilted state, and the sealing force of the O-ring 176 is reduced.

[0050] For example, in the present embodiment, the angle α is 1.2 degrees, which results in a height difference H of 0.2 mm above the opening 107. That is, when the fixed portion 5 is attached to the lens barrel 103 at an inclination of 1.2 degrees around the attachment center O as an axis, the main shaft 71 also inclines 1.2 degrees around the attachment center O as an axis, and the amount of crushing of the seal material is reduced by up to 0.2 mm in some places. The amount of crushing of the seal material sealing the opening 107 is about 0.5 mm, resulting in a loss of about 40% of the sealing force. To airtightly seal the opening 107, the seal material needs to seal the opening 107 horizontally, and it is important to correct the circumferential misalignment by the connection mechanism 3.

[0051] Returning to Fig. 4, the connection portion 43, which is the connection mechanism between the transmission shaft 41 and the connection shaft 42, will be described. A male thread portion 41f is provided at the rear end of the transmission shaft 41. A female thread portion 42a is provided at the front end of the connection shaft 42, which is connected to this, and the transmission shaft 41 and the connection shaft 42 are connected by screwing together the two. Due to the backlash, the structure is such that rotation is not transmitted to the bellows. This prevents strain on the bellows 4 during assembly.

[0052] (Opening and closing mechanism 2) The opening / closing mechanism 2 will be described in detail with reference to Fig. 8 and Fig. 9. Fig. 8 is a cross-sectional view of the opening / closing mechanism 2 in an open state. Fig. 9 is an explanatory diagram for explaining the opening and closing state of the opening 107 by the opening / closing mechanism 2, where (A) shows the open state and (B) shows the closed state.

[0053] As described above, the opening / closing mechanism 2 is made up of the fixed-side mechanism 8 fixed to the partition wall 106, and the movable-side mechanism 7 that moves in conjunction with the advancement and retreat of the actuator 6.

[0054] The fixed-side mechanism 8 includes a support member 81, upper rollers 82 and 83, and a lower roller 84. The movable-side mechanism 7 includes a main shaft 71, an auxiliary member 72, a spring 73, a pair of links 74, a valve body 75, an O-ring 76, and a bolt 77.

[0055] The support members 81 are a pair of L-shaped brackets, which face each other at positions that do not impede the movement of the electron beam EB or the movable mechanism 7, are fixed to the partition wall 106 on a horizontal plane, and rotatably support the upper rollers 82, 83 and the lower roller 84 on a vertical plane (see FIG. 2). For the sake of explanation, one of the support members 81 arranged on the front side of the page is omitted in FIG. 9.

[0056] The upper rollers 82, 83 are rotating bodies for suppressing deformation of the main shaft 71, that is, for suppressing the main shaft 71 from bending upward due to the reaction force generated by pressing the valve body 75 against the opening 107. The upper rollers 82, 83 are arranged in parallel to the advancing and retracting direction of the main shaft 71, and their rotation axes are perpendicular to the advancing and retracting direction of the main shaft 71, but since they do not play a role like a conveyor that guides the advancing and retracting movement of the main shaft 71, it is preferable that they approach the main shaft 71 in the open state but do not come into contact with it.

[0057] The upper rollers 82, 83 are disposed above the main shaft 71 in a position facing the opening 107 below with the main shaft 71 in between in the up-down direction. Furthermore, with respect to the forward and backward direction (front-rear direction) of the main shaft 71, the upper roller 83 is disposed on the tip side of the main shaft 71 and the upper roller 82 is disposed on the base end side of the main shaft 71 with the opening 107 as a reference. By disposing the two upper rollers 82, 83 on either side of the opening 107, deformation of the main shaft 71 can be stably and firmly suppressed.

[0058] The valve element 75 has a substantially rectangular parallelepiped shape and is linked and connected to the main shaft 71 by a pair of links 74. The valve element 75 moves up and down as the main shaft 71 moves back and forth, thereby directly opening and closing the opening 107.

[0059] The spring 73 is an elastic body for biasing the valve body 75 in a direction to maintain the valve body 75 in an open state. The forward bias of the spring 73 is converted into an upward bias by the link 74, and in the open state, the valve body 75 is maintained in a state separated from the partition wall 106.

[0060] The lower roller 84 is disposed in front of the valve body 75, facing the upper roller 83 across the main shaft 71. An inclined surface 75b is formed on the front surface of the valve body 75, and when the main shaft 71 moves back and forth, the lower roller 84 comes into contact with the inclined surface 75b, moving the valve body 75 up and down.

[0061] The inclined surface 75b has a very steep gradient. After the valve body 75 abuts against the lower roller 84, it moves in the gradient direction of the inclined surface 75b, so the gradient is made large to move the valve body 75 approximately vertically. If the inclined surface 75b has a gentle gradient, the valve body 75 moves up and down and the amount of movement in the front and rear directions increases from when the O-ring 76 comes into contact with the sealing surface until it is completely sealed, and the O-ring 76 slides against the partition wall 106, which is the sealing surface, until it is completely sealed. In a high vacuum atmosphere, no sliding force works, and a large load is applied to the O-ring 76 due to twisting and high friction sliding. The inclined surface 75b has a steep gradient to reduce damage to the O-ring 76 and improve its durability. Specifically, an inclination angle of 70 degrees or more is preferable.

[0062] The auxiliary member 72 is an auxiliary member for holding the spring 73, and is formed with a deep recess 72a for holding the spring 73. The auxiliary member 72 is disposed on the rear surface of the valve body 75 and is fixed to the bottom surface of the main shaft 71 by bolts 77 so that the spring 73 can efficiently bias the valve body 75. It is also possible to have a configuration in which the spring 73 is directly held by the main shaft 71 without using the auxiliary member 72.

[0063] The O-ring 76 is a seal member for air-tightly sealing the opening 107. A dovetail groove 75a is provided in an annular shape on the lower surface of the valve body 75, and the O-ring 76 is attached to the lower surface of the valve body 75 by fitting into this groove.

[0064] Also, the valve body 75 is connected to the link 74 at a thin-walled portion 75d having a cut-away side so as to eliminate any step between the valve body 75 and the link 74 and to smoothly connect to the link 74. This reduces the width of the moving mechanism 7.

[0065] The valve body 75 and the main shaft 71 are provided with through holes 75c and 71c for passing the electron beam EB, respectively. When the opening / closing mechanism 2 is assembled, the through holes 75c and 71c are configured to communicate with each other. As described above, the connection mechanism 3 allows fine adjustment of the position of the main shaft 71 in the front-rear direction, and when the opening / closing mechanism 2 is in the open state, the position is adjusted so that the opening 107 and the through holes 75c and 71c are aligned in a straight line in the vertical direction. This ensures a path for the electron beam EB.

[0066] Of course, the valve 75 and the main shaft 71 are made of non-magnetic material so as not to adversely affect the electron beam EB. By providing holes in the valve 75 and the main shaft 71 that serve as paths for the electron beam EB, the valve 75 can be positioned above the opening 107 even in the open state, and the amount of forward and backward movement of the main shaft 71 required to open and close the opening 107 is reduced, minimizing the generation of particles due to metal sliding.

[0067] In this embodiment, the link mechanism that displaceably connects the valve body 75 and the main shaft 71 is composed of a pair of links 74. The pair of links 74 face each other on both sides of the valve body 75, linking and connecting the valve body 75 and the main shaft 71. Therefore, a rotation axis 74a between the link 74 and the valve body 75 is horizontal (see FIG. 8. The rotation axis 74a extends in the depth direction of the paper). The valve body 75 is supported so as to be rotatable in the vertical direction about the rotation axis 74a. By configuring the link mechanism in this way, the inclination of the valve body 75 in the front-rear direction that occurs when the fixed part 5 is fixed to the lens barrel 103 is corrected. The inclination of the valve body 75 in the front-rear direction refers to the inclination from the horizontal about a horizontal axis that is perpendicular to the forward and backward direction of the main shaft 71.

[0068] For example, if the mounting surface of the fixed part 5 formed on the side wall 103a is inclined at an angle β from the vertical, the fixed part 5 is also inclined at an angle β from the vertical, so that the main shaft 71 is in a state in which the front end is lowered (or raised) by the angle β. Therefore, in the mounted state, the inclination of the valve body in the front-rear direction is also angle β. If the valve body is supported by a link mechanism using four links (two pairs of links), the valve body cannot rotate, so that the inclined state cannot be eliminated, and the opening is sealed in the inclined state. In contrast, in this embodiment, the valve body 75 is supported rotatably on the rotating shaft 74a by a pair of links 74, so that even if the valve body is inclined by angle β in the mounted state, the force of the inclined surface 75b moving it in the vertical direction causes the valve body 75 to rotate on the rotating shaft 74a, lowering (or raising) the rear end to a horizontal state, and uniformly sealing the opening 107. As described above, in this embodiment, if the main shaft is inclined by 1.2 degrees, the sealing force is lost by about 40%, which is a large impact. To airtightly seal the opening 107, the valve body 75 to which the O-ring 76 is attached must seal the opening 107 horizontally. Furthermore, slight play when mounting the fixed part 5 and unevenness on the fixed surface can also cause the valve body 75 to tilt. By using only a pair of links 74 as a link mechanism to rotatably support the valve body 75, such individual differences and errors can be absorbed and the tilt of the valve body 75 in the front-rear direction can be corrected.

[0069] In the valve body 75, the inclination about two horizontal axes (the horizontal axis in the forward and backward direction of the main shaft 71 and the horizontal axis perpendicular to that) is corrected, so that the O-ring 76 seals the opening 107 in a horizontal state, and the opening 107 is hermetically sealed.

[0070] The surface of the partition wall 106 around the opening 107, which serves as the sealing surface for the O-ring 76, is also mirror-finished to improve sealing performance.

[0071] 8 and 9, the partition wall 106 around the opening 107 is configured as a slightly higher step 106a. This is to reduce the possibility that particles will fall into the sealed area even if they are generated by the sliding of metals due to the movement of the opening / closing mechanism 2. Furthermore, particles that fall from the step 106a are less likely to climb up onto the step 106a again, i.e., the sealed area, so that a decrease in sealing performance can be suppressed.

[0072] Action and effect of opening and closing mechanism 2) When the opening / closing mechanism 2 is in the open state, the valve body 75 is biased by the spring 73 and is disposed away from the partition wall 106 (see FIG. 9(A)). When the main shaft 71 moves forward and the inclined surface 75b comes into contact with the lower roller 84, the valve body 75 moves downward to seal the opening 107 (see FIG. 9(B)).

[0073] The forward motion of the main shaft 71 is converted by the lower roller 84 into the downward movement of the valve body 75, and the valve body 75 moves downward, causing the O-ring 76 to press against the partition wall 106, but receives an upward reaction force from the partition wall 106 (arrow DR1 in FIG. 9(B)). The upper rollers 82, 83 come into contact with the main shaft 71, which tries to warp in response to this upward reaction force, and suppress deformation of the main shaft 71 (arrows DR2, DR3 in FIG. 9(B)). In the conventional configuration without the upper rollers 82 and 83, the main shaft would bend into an arch shape due to the reaction force from the partition wall even if the valve body was moved to the opening. This caused the O-ring to be pressed at an angle, making it impossible to obtain a uniform pressing pressure and maintaining a high sealing effect.

[0074] In contrast, in this embodiment, by arranging upper rollers 82, 83 on the upper part of the main shaft 71, the upper rollers 82, 83 receive the reaction force and prevent the main shaft 71 from warping, and the O-ring 76 obtains a uniform pressing pressure, thereby enabling the opening 107 to be airtightly sealed.

[0075] Furthermore, the pressing force of the valve body 75 is prevented from escaping in the direction opposite to the opening 107 as a reaction force, thereby preventing a decrease in the pressing force of the valve body 75, and the forward motion of the main shaft 71 can be converted with high efficiency into the pressing force of the valve body 75. As a result, the valve body 75 air-tightly seals the opening 107.

[0076] Since the amount of movement of the main shaft 71 in the forward and backward directions for opening and closing the opening 107 is small, metal sliding can be suppressed accordingly, and the generation of particles can be suppressed.

[0077] In addition, in the conventional vacuum seal valve, the opening and closing mechanism is large and cannot be removed from the vacuum chamber, or both the lens barrel and the vacuum seal valve must be disassembled to remove the vacuum seal valve, making it difficult to replace the O-ring. In addition, in order to maintain a high degree of vacuum in the vacuum chamber, it is preferable that the through hole of the lens barrel through which the drive source outside the lens barrel and the seal valve inside the lens barrel are inserted is small. In this embodiment, the upper rollers 82, 83 and the lower roller 84 are fixed to the partition wall 106 as the fixed side mechanism 8, and the movable side mechanism 7 is compactly configured, so that the movable side mechanism 7 can be removed from the through hole 109. This makes it easy to repair the malfunction and to replace the O-ring 76. In particular, in the electron microscope 100, which requires a high degree of vacuum, it is important that the O-ring 76, which is easily deteriorated, can be easily replaced in order to hermetically seal the opening 107.

[0078] (Modification) The configuration of the present disclosure is not limited to the above embodiment. A modified example is shown in FIG. 10. Components having equivalent configurations are given the same reference numerals and will not be described. As shown in FIG. 10, the first connecting member 31 is provided with a male screw portion 131d protruding from the center of the front surface thereof, which is screwed into a female screw portion 132a provided in the center of the back surface of the second connecting member 32, thereby connecting the first connecting member 31 and the second connecting member 32 in such a way that the connection length can be adjusted. In this way, the screw connection between the first connecting member 31 and the second connecting member 32 may be reversed in male-female configuration.

[0079] Furthermore, the engaging member that engages successively with the first connecting member 31 and the second connecting member 32 is not limited to the headless bolt 34. As shown in Fig. 10, a pin 134, a screw, or the like may be used. The pin 134 is a cylindrical body, and an engaging hole 132c is formed as a through hole in the second connecting member 32 corresponding to the shape of the pin 134. The first connecting member 31 has an insertion hole 131c formed at a position that can be aligned in series with the engaging hole 132c.

[0080] When the pin 134 is inserted into the engagement hole 132c from the front side and engaged therewith after the first connection member 31 is screwed to the second connection member 32 and the positioning of the main shaft 71 is adjusted in the front-rear direction, the tip portion 134a protrudes from the rear surface of the second connection member 32 and is inserted into the insertion hole 131c. The inner diameter of the insertion hole 131c is set to be slightly larger than the outer diameter of the tip portion 134a of the pin 134, so that the tip portion 134a is placed in the insertion hole 131c with some clearance. The insertion hole 131c is a through hole, and when removing the pin 134, it is pushed in as it is and taken out from the rear surface side of the first connection member 31.

[0081] Just as the headless bolt 34 is engaged with the first connecting member 31 and a portion of it protrudes into the insertion hole 32c of the second connecting member 32, the pin 134 is engaged with the second connecting member 32 and a portion of it protrudes into the insertion hole 131c of the first connecting member 31. In this manner, the engagement configuration may be reversed. The engaging member may be configured such that, when engaged with the first connecting member 31 or the second connecting member 32, a portion of it protrudes into the hole of the other connecting member, and the maximum outer diameter of the engaging member is smaller than the inner diameter of the hole of the other connecting member, leaving some clearance with the inner wall of the hole.

[0082] The engagement hole 132c and the insertion hole 131c in which the pin 134 is disposed are provided on a circle of the same diameter centered on the axis of the screw engagement so that they can be arranged in series. The engagement holes 132c are provided at two locations facing each other around the screw engagement axis of the male screw portion 131d and the female screw portion 132a, and the insertion holes 131c are provided at six locations at unequal angles avoiding the screw hole 31b. In this way, it is preferable that the holes in which the engagement members are disposed are provided at multiple locations at equal or unequal intervals centered on the axis of the screw engagement, because this allows the arrangement of the main shaft 71 to be adjusted more precisely.

[0083] Although the preferred embodiments of the present invention have been described above, modifications can be made based on the knowledge of those skilled in the art, and such modifications are within the scope of the present invention. [Explanation of symbols]

[0084] 1: Vacuum sealing valve 71: Main shaft 71c: Through hole 75: Valve body 75c: Through hole 82, 83: Upper roller 84: Lower roller 106: Partition wall 107: Opening

Claims

1. a valve body for sealing / unsealing an opening formed in the wall body; A shaft member that is movable back and forth substantially parallel to the wall body; a link mechanism that displaceably connects the valve body and the shaft member to each other; a conversion mechanism that converts the forward and backward movement of the shaft member into movement of the valve body toward the opening via the link mechanism; a roller that is disposed at a position facing the opening with the shaft member interposed therebetween and that abuts against the shaft member in a sealing state of the valve body to suppress deformation of the shaft member; Equipped with The roller is disposed apart from the shaft member when the valve body unseals the opening. A vacuum seal valve characterized by:

2. At least two rollers are provided, With respect to the opening, one or more are disposed on each of the base end side and the tip end side of the shaft member.

2. The vacuum seal valve according to claim 1.

3. The valve body and the shaft member are formed with a hole that is aligned with the opening when the valve body is in an unsealed state.

3. The vacuum seal valve according to claim 1 or 2.

4. the conversion mechanism is a second roller that comes into contact with an inclined surface provided at a tip portion of the valve body, the second roller is disposed at a position substantially directly opposite the roller with the shaft member therebetween and slightly spaced from the shaft member; 4. The vacuum seal valve according to claim 1, wherein the first and second electrodes are disposed in a first and second positions.

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