JP7141874B2 - Luminescence lighting device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a lighting device or the like for collecting cathodoluminescence emitted when a sample is irradiated with an electron beam, and more particularly to a device suitable for use in an electron microscope.

A luminescence lighting device of this kind is used, for example, by being inserted between the pole pieces of a transmission electron microscope (TEM), and reflects the cathodoluminescence emitted from the sample directly to a detector having a spectrometer. Alternatively, it has a reflector for guiding through a light guide such as an optical fiber.

By the way, as described in Patent Document 1, the distance between the pole pieces should be as short as possible in order to improve device performance such as resolution, so the thickness of the luminescence lighting device inserted between them should be as small as possible. It is desired that

However, if the thickness is limited by, for example, providing a reflecting mirror only above or below the sample, the lighting efficiency of cathodoluminescence, which is weak in the first place, is reduced, and problems such as a poor SN ratio may occur.

Moreover, since the conventional luminescence daylighting device has a slide adjustment mechanism for adjusting the position of the reflecting mirror, it is difficult to reduce the dimension in the thickness direction by a certain amount or more.

Japanese Patent Publication No. 2015-503198

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and the principal object thereof is to provide a luminescence lighting device capable of efficiently taking in cathodoluminescence and having a significantly smaller thickness than conventional devices. This is a topic for the next term.

That is, a luminescence lighting device according to the present invention is for lighting cathodoluminescence emitted by irradiating a sample with an electron beam, and includes a holder forming member formed with a sample holder on which the sample is placed, and A reflecting mirror forming member having a reflecting mirror for reflecting the emitted cathodoluminescence and guiding it to a predetermined lighting surface, a contact surface provided on the holder forming member, and a contact surface provided on the reflecting mirror forming member. and a positioning mechanism for setting the relative position of the reflecting mirror with respect to the sample holder to a predetermined unique position by bringing the reflecting mirror into contact with the sample holder.

With such a device, positioning is achieved only by mechanical contact, and a mechanism for adjusting the position of the reflecting mirror is not required. It becomes possible to cope with an electron microscope with a small distance between pole pieces.

As a more specific embodiment, a sample holder is provided so as to protrude from the tip of the holder forming member, and the protruding direction of the sample holder is perpendicular to the electron beam irradiation direction, The reflecting mirror forming member is configured to be fitted and attached to the distal end side of the holder forming member, and the positioning mechanism protrudes from each of the sample holder forming member and the reflecting mirror forming member. a first abutting surface that is a facing surface provided so as to be orthogonal to the direction; a convex portion provided so as to extend in the projecting direction on either the sample holder forming member or the reflecting mirror forming member; The other of the sample holder forming member and the reflecting mirror forming member is provided with a recess recessed in the projecting direction. It may be configured such that positioning in a direction perpendicular to the projecting direction is achieved by abutment of the second contact surfaces, which are the side peripheral surfaces of the convex portion and the concave portion.

In order to make the thickness as small as possible, the convex portion and the concave portion are provided on either or both the left and right sides of the reflecting mirror when the direction orthogonal to the projecting direction and the electron beam irradiation direction is defined as the left-right direction. It is preferable to have With such a device, it is possible to reduce the thickness of the daylighting device to such an extent that the dimension in the thickness direction is almost the same as the dimension in the thickness direction of the reflecting mirror.

As a result, as a reflector that covers the sample from above and below (both sides in the thickness direction), even if the thickness direction dimension of the reflector is increased and the lighting efficiency is emphasized, the distance between the pole pieces of the existing electron microscope is reduced. It becomes possible to keep the thickness so that it can be sufficiently inserted into the.

If a fixing mechanism for fixing the reflecting mirror forming member to the holder forming member at the predetermined position is further provided, and the fixing mechanism is provided on either the left or right side of the reflecting mirror or on both sides, the thickness can be reduced. can contribute to

As described above, according to the present invention, positioning is achieved only by mechanical contact, and a mechanism for adjusting the position of the reflecting mirror is not necessary. It becomes possible to correspond to an electron microscope with a small distance between pole pieces.

FIG. 1 is a vertical cross-sectional view taken along the thickness direction, showing a state in which a luminescence daylighting device according to an embodiment of the present invention is arranged between pole pieces. FIG. 2 is an exploded perspective view of the luminescence daylighting device according to the embodiment; FIG. 2 is a vertical cross-sectional view of the luminescence daylighting device according to the same embodiment taken along the left-right direction. FIG. 3 is an exploded vertical cross-sectional view of the luminescence daylighting device according to the same embodiment cut along the left-right direction. The schematic diagram which occupies the cooling mechanism in other embodiment of this invention. FIG. 5 is a vertical cross-sectional view taken along the thickness direction of a luminescence daylighting device according to still another embodiment of the present invention.

A lighting device 100 according to an embodiment of the present invention will be described below with reference to the drawings.

As shown in FIG. 1, a lighting device 100 according to this embodiment holds a sample and is inserted between pole pieces P of an electron microscope, and collects cathodoluminescence emitted from the sample irradiated with an electron beam. It fulfills the function of leading to a light receiving element (not shown).

More specifically, as shown in FIGS. 2, 3, 4, etc., the lighting device 100 includes a holder forming member 1 having a sample holder 11 on which a sample is placed, and a A reflecting mirror forming member 22 formed with a reflecting mirror 21 for reflecting cathodoluminescence and guiding it to a predetermined lighting surface S, and a positioning mechanism 3 for positioning the reflecting mirror forming member 2 at a predetermined position of the holder forming member 1. and a fixing mechanism 4 for fixing the positioned reflecting mirror forming member 2 to the holder forming member 1 .

Each part will be explained.

The holder forming member 1 is composed of a flat rectangular plate-shaped substrate 12 and a rectangular plate-shaped sample holder 11 projecting integrally from the front end surface of the substrate 12 . Hereinafter, the projecting direction of the sample holder 11 is also referred to as the front-rear direction, the plane direction of the substrate 12 (and the sample holder 11) as the thickness direction, and the direction orthogonal to the front-rear direction and the thickness direction as the left-right direction.

The substrate 12 is formed with a notch 12b of a constant width extending rearward from the center of the tip surface 12a in plan view, and the tip of the optical fiber F inserted from the rear side of the substrate 12 is formed. The surface is configured to be exposed on the bottom surface of the notch. The tip surface of the optical fiber becomes the lighting surface S. Although the lighting surface S protrudes from the bottom surface, it may be set at a recessed position.

The specimen holder 11 is thinner than the substrate 12 and has a rectangular plate-like shape smaller in lateral dimension than the light collecting body. integrally extended from the A through-hole 12c is provided in the center of the sample holder 11 near the tip, and a mesh sheet 111 is placed in the center of the through-hole 12c in the thickness direction, as shown in FIG. affixed. A sample is placed and held in the center of this sheet 111 . That is, the central portion of this sheet pasting area becomes the sample holding area of the sample holder 11 .

The reflecting mirror forming member 2 is in the form of a flat rectangular plate having a thickness equal to or slightly larger than that of the base 12 of the holder forming member 1. At the center of the rear end face 2a, the reflecting mirror 21 is formed. A concave portion having a partially ellipsoidal shape is provided. The diameter of this recess, that is, the opening diameter of the reflecting mirror, is set to be the same as or slightly smaller than the dimension in the thickness direction of the rear end face 2a of the reflecting mirror forming member 2 (80% to 95% in terms of ratio).

A holder insertion groove 2b extending in the left-right direction along the center in the thickness direction is formed in the rear end face 2a. The thickness of the holder insertion groove 2b is set to be equal to the thickness of the sample holder 11, so that the sample holder 11 is fitted into the holder insertion groove 2b in the thickness direction without backlash. When the reflecting mirror forming member 2 is attached to the predetermined position of the distal end portion of the holder forming member 1, the distal end portion of the sample holder 11 is inserted into the holder insertion groove 2b, and the reflecting mirror 21 is inserted into the sample holder 11. It is configured to cover the sample holding area from the tip side. Beam through holes 2c for passing electron beams are provided above and below the focal position of the reflecting mirror 21, that is, in the thickness direction.

The positioning mechanism 3 brings the contact surfaces provided on the holder forming member 1 and the reflecting mirror forming member 2 into contact with each other so that the relative position of the reflecting mirror 21 with respect to the sample holder 11 is determined in advance. A predetermined position, namely the elliptical focal point of one of the reflectors 21, is aligned with the center of the sample holding area in a unique position. The other elliptical focal point of the reflecting mirror 21 is positioned on the lighting surface S. As shown in FIG.

More specifically, the positioning mechanism 3 positions the holder forming member 1 in the longitudinal direction by abutting the front end surface 12a of the base 12 and the rear end surface 2a of the reflecting mirror forming member 2 on the holder forming member 1. Further, positioning in the left-right direction and the thickness direction is achieved by fitting the concave-convex structure provided on the reflecting mirror forming member 2 without backlash (contact between the side peripheral surfaces of the concave-convex structure).

In this embodiment, the concavo-convex structure includes a pair of cylindrical pin members 31 of equal diameter that protrude from both sides of the sample holder 11 on the front end surface 12a of the substrate 12 in the projecting direction, A pair of fitting holes 32 are provided so as to penetrate in the front-rear direction at positions corresponding to the pin members 31 on the end face 2a.

In positioning, the rear end face 2a of the reflector forming member 2 is brought close to the tip end side of the holder forming member 1, and each pin member 31 is fitted into each fitting hole 32. The rear end surface 2a of the reflecting mirror forming member 2 is brought into contact with 12a.

The fixing mechanism 4, as shown in FIGS. By inserting the screw 42 through the opening and screwing it into the female screw hole 41 of the pin member 31 inside the fitting hole 32, the head of the screw 42 presses the tip surface 12a of the reflector forming member 2, The reflecting mirror forming member 2 at the predetermined position is fixed so as not to come off from the holder forming member 1 . The outer diameter of the head of the screw 42 is set smaller than the thickness dimension of the reflector forming member 2, and the head is positioned within the thickness of the reflector forming member 2 when the screw 42 is attached. .

The lighting device 100 constructed by fitting the reflector forming member 2 to the tip of the holder forming member 1 in this manner is inserted between the pole pieces P with its thickness direction aligned with the electron beam irradiation direction. It is arranged at a position where the electron beam passes through the through hole 2c.

Then, when an electron beam is emitted, the electron beam passes through the beam through hole 2c and irradiates the sample inside, and cathodoluminescence is generated from the irradiated portion. This cathodoluminescence is reflected by the reflecting mirror 21, converged on the light collection surface S at the other focal position, introduced into the optical fiber, and guided to a light receiving element (not shown).

Thus, according to the daylighting device 100 configured in this manner, the positioning mechanism 3 is employed to position the reflecting mirror 21 at a unique predetermined position only by the mechanical contact surface, and no adjustment mechanism or the like is required. is simple, and the positioning mechanism 3 and the fixing mechanism 4 are provided substantially only in the lateral direction of the reflecting mirror 21 and are arranged within the thickness of the reflecting mirror 21, so that the thickness of the daylighting device 100 The directional dimension is almost equal to the thickness dimension of the reflector 21 .

Therefore, the reflecting mirror 21 covers the top and bottom of the sample, and the thickness dimension of the lighting device 100 can be kept extremely small while improving the lighting efficiency of cathodoluminescence. is also adequate.

It should be noted that the present invention is not limited to the above embodiments. For example, the concavo-convex structure may be a structure in which a pin member is provided in the reflector forming member and a fitting hole is provided in the holder forming member, and furthermore, the structure is not limited to the pin member and the fitting hole.

Furthermore, this lighting device can be used not only for collecting cathodoluminescence in electron microscopes, but also for collecting cathodoluminescence used in other analytical devices, and can also be used for collecting photoluminescence. is.

As shown in FIG. 5, a cooling mechanism M for cooling the sample holder 11 may be provided. During sample analysis, thermal noise may pose a problem in terms of measurement accuracy, but such a cooling mechanism M can suppress the influence of thermal noise.

The cooling mechanism M includes, for example, a heat conductor M1 extending from the tip of the holder forming member 1 through the outer wall of the vacuum chamber (not shown) to the outside, and a heat conductor M1 provided outside the vacuum chamber and connected to the heat conductor M1. It is provided with a cooling member M2.

A heat pipe member, for example, is employed as the heat conductor M1. The heat pipe members M1 are embedded in the substrate 12 that supports the sample holder 11 here. By connecting a cooling member M2 such as a heat exchanger to the outer tip of the heat pipe member M1, heat is removed from the sample holder 11 through the heat pipe member M1.

The substrate 12 itself may be a heat conductor, or a heat medium circulation path may be provided inside the substrate 12, and the circulating heat medium may form a refrigeration cycle to cool the sample holder 11. can be

Further, as shown in FIG. 6, the sheet 1111 attached to the through hole 12c of the sample holder 11 is attached to the reflector forming member 2 in a state where the reflector forming member 2 is attached to the holder forming member 1. It may be sandwiched between the sample holder 11 and fixed on the sample holder 11 . With such a structure, the sheet 111 can be attached to the sample holder 11 much more easily. Although the sheet 111 is a mesh (grid) sheet, it may be a film-like transparent sheet as long as cathodoluminescence is transmitted through it.

In addition, it goes without saying that the present invention can be modified in various ways without departing from the scope of the invention.

DESCRIPTION OF SYMBOLS 100... Luminescence lighting apparatus 11... Sample holder 1... Holder forming member S... Lighting surface 21... Reflecting mirror 2... Reflecting mirror forming member 3... Positioning mechanism 2a... First contact surface (rear end surface of reflecting mirror forming member)
12a... First contact surface (end surface)
31... Convex portion (pin member)
32... Concave portion (fitting hole)
4: Fixing mechanism P: Pole piece

Claims (8)

Cathodoluminescence emitted by irradiating a sample with an electron beam is taken,
a holder forming member having a sample holder on which the sample is placed;
a reflecting mirror forming member having a reflecting mirror formed thereon for reflecting the cathodoluminescence emitted from the sample and guiding it to a predetermined lighting surface;
Provided between the holder forming member and the reflecting mirror forming member, the contact surface provided on the holder forming member and the contact surface provided on the reflecting mirror forming member are provided , and the contact surfaces are in contact with each other. and a positioning mechanism for setting the relative position of the reflecting mirror with respect to the sample holder to a predetermined unique position by adjusting the position of the reflecting mirror. A sample holder is provided so as to protrude from the tip of the holder forming member, and the sample holder is installed so that the protruding direction of the sample holder is perpendicular to the electron beam irradiation direction, and the reflecting mirror forming member serves as the holder forming member. It is configured to be fitted and attached to the tip side of the member,
The positioning mechanism is
a first contact surface, which is a facing surface provided on each of the holder forming member and the reflecting mirror forming member so as to be perpendicular to the projecting direction;
a convex portion provided on either the holder forming member or the reflecting mirror forming member so as to extend in the projecting direction;
a recess provided in the other of the holder forming member or the reflecting mirror forming member so as to be recessed in the projecting direction;
Positioning in the projecting direction is achieved by contact between the first contact surfaces, and positioning in a direction orthogonal to the projecting direction is achieved by contact between the second contact surfaces, which are side peripheral surfaces of the convex portion and the recess. 2. The luminescence daylighting device according to claim 1, wherein 3. The luminescence lighting device according to claim 2, wherein the convex portion and the concave portion are provided on either one or both of the left and right sides of the reflecting mirror when the direction perpendicular to the projecting direction and the electron beam irradiation direction is defined as a left-right direction. 4. Any one of claims 1 to 3, further comprising a fixing mechanism for fixing said reflecting mirror forming member to said holder forming member at said predetermined position, said fixing mechanism being provided on either one or both of the left and right sides of said reflecting mirror. The described luminescence daylighting device. 5. Any one of claims 1 to 4, further comprising a cooling mechanism for cooling the sample holder, wherein the cooling mechanism transfers heat of the sample holder to the outside of the vacuum chamber accommodating the sample holder via a heat conductor. The described luminescence daylighting device. A translucent sheet is attached to the through hole provided in the sample holder, and the sample is configured to be placed on the sheet,
6. The luminescence lighting device according to any one of claims 1 to 5, wherein the sheet is fixed to the sample holder by the reflecting mirror forming member. 7. An electronic device comprising: the luminescence lighting device according to any one of claims 1 to 6; and a pair of pole pieces through which an electron beam passes, wherein the luminescence lighting device is inserted between the pole pieces. microscope. A holder forming member formed with a sample holder on which a sample is placed in order to capture cathodoluminescence emitted by irradiating a sample with an electron beam, and a holder forming member that reflects the cathodoluminescence emitted from the sample and directs it to a predetermined lighting surface. It is provided between a reflector forming member on which a reflector for
A contact surface provided on the holder forming member and a contact surface provided on the reflecting mirror forming member are provided, and the relative position of the reflecting mirror with respect to the sample holder is determined in advance by bringing the contact surfaces into contact with each other. A positioning mechanism, characterized in that it sets to a unique predetermined position.

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