JPH0355236Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electron beam aperture device provided in an electron lens of an electron microscope.

Among the aperture devices used in electron microscopes and the like, there is a type of device that does not require changing the diameter of the aperture hole. Conventionally, in such an aperture device, the aperture holder is attached by fixing the aperture holder to the magnetic pole piece of the lens, or by providing a structure for attaching the aperture holder to the lens magnetic pole piece. By the way, if the diaphragm is used for a certain period of time, it becomes dirty due to adhesion of carbonized compounds and the like, which adversely affects the electron beam, so it becomes necessary to clean the diaphragm. In order to remove the diaphragm for cleaning, in the former device of the prior art, the stacked lens structure must be disassembled, which requires a lot of work. In addition, even in the conventional latter device, the aperture holder must be removed from the magnetic pole pieces using tweezers or the like, which requires skill and requires a lot of skill to remove the aperture holder from the magnetic pole piece. It is necessary to reserve a large space for.

This invention solves these conventional drawbacks and
The diaphragm can be easily removed and cleaned, and almost no space is required for the removal work.Furthermore, the diaphragm device in an electron microscope does not require mechanical position adjustment of the diaphragm with the diaphragm attached. is intended to provide.

The present invention includes an aperture holder having a semicircular convex part and a mechanism for installing the aperture at the center of the circle, and a semicircular concave part so that the center of the circle coincides with the optical axis. A holder holder fixed to an electronic lens, a supporting means for loosely supporting the diaphragm holder so as not to change the relative position between the holder holder and the diaphragm, and a convex portion of the diaphragm holder that is fixed to the diaphragm even when the electronic lens moves. The aperture holder includes means for applying an elastic force to the aperture holder so as to come into contact with the convex portion of the aperture holder receiver, and means for pulling out the aperture holder together with the support means from the housing tube. .

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 is a diagram showing an embodiment of the present invention. In the figure, 1 is a lens barrel wall of an electron microscope, and a lens barrel wall 2 is stacked on top of this lens barrel wall 1. . This lens barrel wall 2 also serves as a yoke for the focusing lens. 3 is an excitation coil of the focusing lens, and 4 is a magnetic pole piece. This magnetic pole piece 4 is provided with an electron beam passage 5. An opening 6 is provided in a part of the lens barrel wall 1, and an aperture holder support member 7 is inserted into the opening 6 from the atmosphere side. This diaphragm holder support member 7 is composed of a main body 7a and a support rod 7b which is movably provided relative to the main body 7a in a direction perpendicular to the optical axis C. The aperture holder support member main body 7a is attached to the lens barrel wall 1 by screws 8.
is attached to. 9 is a vacuum seal member. The support rod 7b is always pushed in the direction of arrow K by the spring 7c. The support rod 7b has a key groove 7d, into which a key 7e integrated with the main body 7a is inserted, and the range of movement of the support rod 7b is limited to a certain range. At the tip of the support rod 7b, an aperture holder 1 is rotatably mounted around an axis 7f.
0 is attached. The aperture holder 10 is provided with a keyway 10a.
A key 7g integrated with the support rod 7b is inserted into the key 7g, and the rotation range of the aperture holder 10 is limited to a certain range. The tip of the aperture holder 10 has a semicircular convex portion 10b, as is clear from FIG. 2 when FIG. 1 is viewed from the direction of arrow A. At the center position of this circle of the aperture holder 10,
A diaphragm 11 is installed. This diaphragm 11 is held down by a diaphragm presser spring 13 via a washer 12. 14 represents a screw for attaching this leaf spring. On the other hand, a guide 15 having a semicircular recess 15a at the lower end of the magnetic pole piece 4
is attached by screws 16. The center of the circle of this recess 15a is arranged to coincide with the optical axis C. 17 is an electron beam passage hole provided in the aperture holder 10.

In such a configuration, when attempting to attach the aperture 11 for the first time, the aperture holder support member 7 that supports the aperture holder 10 is inserted through the opening 6. As a result, the convex portion 10b at the tip of the aperture holder 10 is inserted into the recess 15a of the guide 15, so that the aperture holder support member 7 is fixed to the lens barrel wall 1 with the screw 8. At this time, the support rod 7b of the aperture holder support member 7 is pushed in the direction of arrow K by the spring 7c, and the aperture holder 10 is rotatable within a certain angle range around the shaft 7f. The convex portion 10b at the tip of the aperture holder 10 contacts the concave portion 15a of the guide 15 without any gap. As a result, the aperture 11 can be positioned at a position where its center coincides with the optical axis C.
Furthermore, even when the lens is moved by a minute amount for mechanical axis alignment, the magnetic pole piece 4 is
Even if the diaphragm 11 moves, the position of the diaphragm 11 can be maintained at the position of the optical axis C.

Now, when cleaning the aperture 11, by removing the screw 8 and pulling out the aperture holder support member 7, the aperture holder 10 can also be pulled out together with this aperture holder support member. The iris 11 can be removed and cleaned immediately.

As is clear from the above description, with the present invention, the diaphragm can be easily removed and cleaned without requiring skilled work using jigs, etc., and there is also little space for the removal work. A diaphragm device in an electron microscope or the like that is unnecessary is provided. Also, with the aperture installed,
Even when the lens is moved by a minute amount for mechanical axis alignment, the aperture moves along with the movement of the lens, so the optical axis and aperture do not shift, making the operation extremely simple. Ru.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of the present invention, and FIG. 2 is a diagram showing FIG. 1 viewed from the direction of arrow A. 1, 2... Lens barrel wall, 3... Excitation coil, 4...
Magnetic pole piece, 5... Electron beam passage, 6... Opening, 7...
Aperture holder, 7a...main body, 7b...support rod,
7c...Spring, 7d, 10a...Keyway, 7e,
7g... Key, 8, 14... Screw, 9... Vacuum seal member, 10... Aperture holder, 11... Aperture, 12... Washer, 13... Leaf spring, 15
...Guide, 17...Electron beam passage hole, C...Optical axis.

Claims (1)

[Scope of utility model registration request] An aperture holder having a semicircular convex part and a mechanism for installing an aperture at the center of the circle, and an electronic lens having a semicircular concave part so that the center of the circle coincides with the optical axis. a fixed holder holder; supporting means for loosely supporting the diaphragm holder so as not to change the relative position between the holder holder and the diaphragm; An electron microscope, etc., comprising means for applying an elastic force to the aperture holder so as to come into contact with a convex portion of the holder receiver, and means for pulling out the aperture holder together with the support means from the housing tube. Squeezing device.