JP2016062751A - Transmission electron microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmission electron microscope of which the structure is simple, small-sized and lightweight.SOLUTION: The transmission electron microscope includes: a vacuum container 10; an electron beam emission part including a pyroelectric crystal 11 disposed within the vacuum container 10, an insulator member 24 which has a lower dielectric constant relative to the pyroelectric crystal 11 and covers one polarized face of the pyroelectric crystal 11, a conductive needle 23 which is erected on the one polarized face of the pyroelectric crystal 11 and includes a protrusive end protruding from the insulator member 24, and temperature change means which changes a temperature of the pyroelectric crystal 11; a specimen holding part 14 which is disposed within the vacuum container 10 and holds a specimen in such a manner that the specimen is positioned on an extension of the protrusive end of the needle 23, the specimen holding part 14 being electrically connected with the other polarized face of the pyroelectric crystal 11 and grounded; and observation means for observing a projection image of the specimen or a diffraction image of the specimen generated by electron beams emitted from the protrusive end of the needle 23 and transmitted through a specimen S.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a transmission electron microscope.

  A transmission electron microscope (hereinafter also referred to as TEM) irradiates a sample with an electron beam, and observes a transmission electron beam image of the sample obtained as a result and an image of the electron beam diffracted by the sample (diffracted electron beam image). It is a device to do. TEM projects an electron beam generator (electron gun), an irradiation system lens, a sample holder, an objective lens, an imaging system lens, a transmission electron beam image, and a diffraction electron beam image in a vacuum container called a lens barrel. Are arranged in order from the top (Patent Documents 1, 2, etc.).

  The electron gun includes a filament (cathode), a Wehnelt electrode (grid), an anode (anode), and a voltage application device, and applies a negative voltage (acceleration voltage) to the cathode to accelerate the electrons. As a result, the sample is irradiated with an electron beam. In TEM, electrons are accelerated by applying a high voltage of 100 kV or higher to the cathode in order to obtain high spatial resolution, and discharge is likely to occur. Therefore, the inside of the lens barrel is in an ultra-high vacuum state or the electron beam is accelerated in multiple stages to keep the applied voltage at each stage low, and the potential gradient is reduced by increasing the distance between each stage, which is undesirable. The discharge is prevented from occurring.

  In addition, as described above, an electron beam emitted from the electron gun is focused in the lens barrel, an irradiation system lens for irradiating the sample with a focused electron beam, a transmission electron beam or a diffracted electron beam enlarged projection image. An objective lens for obtaining, an imaging system lens for imaging a transmission electron beam or a diffraction electron beam on a fluorescent plate, and the like are accommodated. In TEM, the illumination system lens, objective lens, and imaging system lens are usually composed of electronic lenses. In particular, the illumination system lens and the imaging system lens are generally composed of multiple stages of electronic lenses. It is.

JP 2007-242514 JP 2012-199022

  As described above, the conventional TEM has a large number of components incorporated in the lens barrel, and it is necessary to lengthen the lens barrel in order to prevent the occurrence of undesired discharge. It was large and heavy.

  The problem to be solved by the present invention is to provide a small and lightweight transmission electron microscope.

The transmission electron microscope according to the present invention, which has been made to solve the above problems,
a) a vacuum vessel;
b) a pyroelectric crystal disposed in the vacuum vessel; an insulator member having a lower dielectric constant than the pyroelectric crystal and covering one polarization surface of the pyroelectric crystal; and the pyroelectric crystal An electron beam emitter having a conductive needle having a protruding end protruding from the insulator member provided on one polarization surface, and a temperature changing means for changing the temperature of the pyroelectric crystal;
c) a sample holder that is arranged in the vacuum vessel and holds the sample so that the sample is positioned on an extension line of the protruding end of the needle, and is electrically connected to the other polarization surface of the pyroelectric crystal. A sample holder connected to and grounded,
d) observation means for observing a projection image of the sample or a diffraction image of the sample by an electron beam emitted from the protruding end of the needle and transmitted through the sample;
It is characterized by providing.

  A pyroelectric crystal is a crystal in which the magnitude of spontaneous polarization changes with changes in temperature. In the equilibrium state, the charged particles floating around the surface adhere to the surface, so that the charge on the pyroelectric crystal surface due to the polarization is canceled out, and an electrically neutral state in which no electric field appears outside is maintained. When a temperature change is given to the pyroelectric crystal from this state, the polarization state of the pyroelectric crystal changes, and the surface is charged positively or negatively. Thereafter, when the temperature is kept constant, the surface charge is eliminated by the suspended charged particles. Since there are a large number of floating charged particles in the atmosphere, the charge on the surface of the pyroelectric crystal is quickly eliminated. However, in the vacuum, the charge on the surface of the pyroelectric crystal is eliminated because there are few floating charged particles. It takes a few minutes to complete.

  In a state in which the surface of the pyroelectric crystal is charged, a sample holding unit disposed so as to face one polarization surface of the pyroelectric crystal and electrically connected to the other polarization surface of the pyroelectric crystal; An electric field is generated between the pyroelectric crystals. Therefore, when one polarization surface of the pyroelectric crystal is negatively charged, negative floating charged particles (electrons) are accelerated from the pyroelectric crystal toward the sample holding portion. In the present invention, a conductive needle is erected on one polarization surface of the pyroelectric crystal, and the one polarization surface of the pyroelectric crystal is covered with an insulating member so that the tip of the needle protrudes. The potential gradient between one polarization surface of the electrocrystal and the sample held in the sample holder is locally increased between the tip (protruding end) of the needle and the sample, and between the polarization surface other than the needle and the sample. The potential difference is almost zero. As a result, only the stray electrons existing in the vicinity of the protruding end of the needle are accelerated toward the sample held in the sample holder, so that the electron beam is applied to a narrow range located on the extension line of the protruding end of the needle in the sample. Can be focused and irradiated. Therefore, in the present invention, an electron lens used for converging an electron beam in a normal TEM and a mechanism for accelerating the electron beam can be omitted, and the apparatus can be reduced in size and weight. it can. Note that the greater the spontaneous polarization of the pyroelectric crystal, and the smaller the area of the tip of the needle, the greater the potential gradient between the sample held in the sample holder and the needle.

In a vacuum, when the pyroelectric crystal is subjected to a temperature change of about 100 ° C. to charge its surface, floating electrons in the atmosphere are accelerated and an electron beam is generated. Compared to the energy required for accelerating the electron beam in the conventional transmission electron microscope, the energy required to give a temperature change of about 100 ° C. to the pyroelectric crystal is small. it can. In addition, the atmosphere for generating an electron beam from the pyroelectric crystal may be higher than 2 × 10 ⁻² Torr (about 2.67 Pa). In general TEM, in order to prevent electric discharge and to prevent deterioration and cutting of the electron gun filament, an ultra vacuum of 1 × 10 ⁻⁶ Torr (about 1.33 × 10 ⁻⁴ Pa) is used. Compared with the requirement, the present invention can employ a seal structure having a low pressure resistance as the seal structure of the vacuum vessel, so that the manufacturing cost can be reduced.

  The observation means transmits, for example, a fluorescent plate disposed in the vacuum vessel so as to be positioned on the opposite side of the conductive needle across the sample held in the sample holding unit, and the sample projected on the fluorescent plate. An imaging unit that images a projection image of the sample by an electron beam or a diffraction image of the sample can be used.

  In the transmission electron microscope according to the present invention, an electron beam can be focused and irradiated on a narrow area of a sample without a focusing lens, but a focusing lens is provided between the electron beam emitting portion and the sample holding portion. The magnification may be increased according to this configuration. Furthermore, if an objective lens is disposed between the sample holder and the observation means, the magnification can be further increased.

  The temperature changing means may include a Peltier element in contact with the pyroelectric crystal and power supply means for supplying power to the Peltier element. According to such a configuration, it is possible to further reduce the size of the transmission electron microscope.

  According to the present invention, the electron beam emitting portion can be reduced in size, and further, an electron lens for focusing the electron beam and components for applying a voltage can be omitted. Can be lighter.

1 is a schematic configuration diagram showing a first embodiment of a transmission electron microscope according to the present invention. The figure for demonstrating a mode that an electron beam goes to a sample from a needle | hook. Explanatory drawing of magnification. The example of the sample observed using the transmission electron microscope which concerns on a present Example is shown, (a) is a SEM image of a copper mesh, (b) is a solid image of a copper mesh. The transmission electron beam image when the distance from the tip of the needle to the fluorescent plate is fixed to 55 mm and the distance from the tip of the needle to the sample is changed to 5 mm (a), 3 mm (b), and 1 mm (c) is shown. Transmission electron beam when the distance from the tip of the needle to the sample is fixed to 1 mm and the distance from the tip of the needle to the fluorescent plate is changed to 15 mm (a), 30 mm (b), 45 mm (c), or 50 mm (d) Show the image. The schematic block diagram which shows 2nd Example of the transmission electron microscope which concerns on this invention. The figure for demonstrating a mode that an electron beam goes to a sample from a needle | hook. The longitudinal side view (a) and solid image (b) of an electronic lens. The transmission electron beam image (a) when using the transmission electron microscope of a present Example, and the graph (b) which shows the magnitude | size and emitted light intensity of a transmission electron beam image. The transmission electron beam image (a) when using the transmission electron microscope of 1st Example, and the graph (b) which shows the magnitude | size and emitted light intensity of a transmission electron beam image. The figure explaining the principle in which an electron beam is irradiated to a sample with a pyroelectric crystal.

  Specific examples of the transmission electron microscope according to the present invention will be described with reference to the drawings.

[Example 1]
FIG. 1 is a schematic configuration diagram of a transmission electron microscope according to the first embodiment of the present invention. In the following description, in FIG. 1, the + z direction is “up” and the −z direction is “down”.
A transmission electron microscope shown in FIG. 1 includes a grounded conductive vacuum vessel 10, a pyroelectric crystal 11 made of a single crystal of 6 mm × 6 mm × 5 mm rectangular LiTaO 3 disposed in the vacuum vessel 10, and A Peltier element 12 for heating / cooling the pyroelectric crystal 11, a power supply device 13 for supplying power to the Peltier element 12, a sample holder 14 for holding the sample S, and an electron beam or a sample transmitted through the sample S A fluorescent plate 15 on which an electron beam diffracted by S is incident; and an imaging device 16 including a digital camera or the like for taking an electron beam image on the fluorescent plate 15.

  The vacuum vessel 10 is composed of a metal tube, for example, a stainless steel tube, and includes a vertical tube portion 101, a horizontal tube portion 102 extending in the horizontal direction from the vicinity of the vertical center of the vertical tube portion 101, and upper and lower portions of the vertical tube portion 101. A window tube 103 extending obliquely downward at an angle of about 45 ° from an opening formed slightly above the central portion in the direction. The upper and lower ends of the vertical pipe portion 101 are closed by flat lids 104 and 105, respectively. A bellows duct 17 connected to a rotary pump (not shown) as a vacuum pump is connected to the tip of the horizontal tube portion 102. Further, a glass window plate 106 is attached to the end opening of the window tube portion 103, and the imaging device 16 is disposed outside the vacuum container 10 so as to face the window plate 106. Although not shown in detail, the vertical pipe part 101 and the window pipe part 103 and the vertical pipe part 101 and the horizontal pipe part 102 are all in close contact by welding or the like. In addition, the space between the vertical tube portion 101 and the lids 104 and 105, the space between the horizontal tube portion 102 and the bellows duct 17, and the space between the tube portion 103 for window and the window plate 106 are hermetically sealed through seal members such as O-rings. It is detachably connected.

  Openings are respectively formed in the lids 104 and 105 at both ends of the vertical pipe portion 101, and the first rod 20 and the second rod 21 made of copper are inserted into these openings. The upper part of the first rod 20 and the lower part of the second rod 21 protrude from the vacuum vessel 10, and the first rod 20 and the second rod 21 are grounded by a conductive wire connected to these protruding ends. The first rod 20 and the second rod 21 are hermetically and electrically connected to the openings of the lids 104 and 105 with an epoxy adhesive, silver paste, or the like. For this reason, the vacuum vessel 10 is also in a state of being grounded in the same manner as the first rod 20 and the second rod 21.

  The pyroelectric crystal 11 is bonded to the upper surface of the second rod 21 via the Peltier element 12. The Peltier element 12 is connected to a power supply device 13, and the pyroelectric crystal 11 is heated / cooled by supplying a current from the power supply device 13. The pyroelectric crystal 11 is arranged so as to be vertically polarized by a temperature change. In particular, in this embodiment, by cooling the pyroelectric crystal 11, the upper side of the pyroelectric crystal 11 becomes positive and the lower side becomes negative. As a result, the upper surface is negatively charged (−) and the lower surface is positively (+) charged. That is, in the present embodiment, the upper surface and the lower surface of the pyroelectric crystal 11 are polarization surfaces. Note that the pyroelectric crystal 11 may be arranged so that the polarization plane is upside down from the present embodiment. In this case, when the pyroelectric crystal 11 is heated, the upper surface of the pyroelectric crystal 11 is negatively polarized (positively charged), and the lower surface is positively polarized (negatively charged).

  The power supply device 13 has a function of periodically switching the direction of the current supplied to the Peltier element 12 every several minutes. As a result, the upper surface of the Peltier element 12 periodically repeats heat absorption and heat dissipation, and accordingly, the pyroelectric crystal 11 bonded to the upper surface of the Peltier element 12 is periodically cooled and heated to change the temperature. As a result, the pyroelectric crystal 11 is polarized positively and negatively or negatively and positively. Therefore, in this embodiment, the Peltier element 12 and the power supply device 18 constitute a temperature changing means.

  As shown in FIGS. 1 and 2, a metal, for example, copper support base 22 is joined to the upper surface of the pyroelectric crystal 11, and a conductive needle 23 is erected on the support base 22. . As a material of the needle 23, a conductive metal such as tungsten or gold can be used. In this example, a gold wire having a diameter of 0.2 mm and a length of 5 mm was used as the needle 23.

In addition, an insulating grease 24 is applied to the surface of the support table 22 in order to prevent the generation of an electric field from the surface of the support table 22. At this time, the thickness of the grease 24 applied to the support base 22 is set so that the tip of the needle 23 protrudes from the grease 24. The grease 24 is preferably a grease with a small change in hardness due to a change in temperature or pressure, and in particular, a vacuum grease (used for airtight maintenance of a rubber gasket surface of a vacuum device and lubrication of a friction surface of a cock of a vacuum valve). For example, silicone grease) and high-voltage insulating grease (for example, silicone grease) are suitable. The relative dielectric constant of silicone is about 3, which is sufficiently smaller than the relative dielectric constant of LiTaO ₃ (about 50). From this point, silicone grease is preferable.
The pyroelectric crystal 11, the needle 23, the grease 24, the Peltier element 12, and the power supply device 13 constitute the electron beam emitting unit of the present invention.

  As shown in FIG. 1, a fluorescent plate 15 is bonded to the lower surface of the first rod 20. The lower surface of the fluorescent plate 15 is substantially orthogonal to the extension line of the needle 23. The fluorescent plate 15 is obtained by applying zinc sulfide (ZnS) to which copper (Cu) and aluminum (Al) are added to an aluminum foil, and is excited to emit light when an electron beam hits the zinc sulfide. The state of light emission of the fluorescent plate 15 is photographed by the image pickup device 16 through the window tube portion 103 attached to the vertical tube portion 101 at an angle of about 45 °.

  The sample holder 14 is a tube-shaped member made of vinyl chloride. The lower part of the sample holder 14 is fitted into the upper outer periphery of the second rod 21, and the sample S is held on the upper end of the sample holder 14. At this time, the length of the sample holder 14 is set so that the sample S is positioned between the tip of the needle 23 and the fluorescent plate 15 and the sample S and the fluorescent plate 15 face each other in a substantially parallel state. Further, the distance from the tip of the needle 23 to the sample S and the distance from the sample S to the fluorescent plate 15 can be changed by changing the mounting position of the sample holder 14 with respect to the second rod 21.

  Note that the lower surface of the pyroelectric crystal 11 is electrically connected to the second rod 21 by a conducting wire or the like. Further, the sample S held by the sample holder 14 is electrically connected to the second rod 21 by a conducting wire. Furthermore, as described above, since the second rod 21 is grounded by a conducting wire or the like, both the sample S and the lower surface of the pyroelectric crystal 11 are at ground potential.

Next, the operation of the transmission electron microscope of this embodiment will be described with reference to FIG.
The sample S is held by the sample holder 14, and the sample S and the second rod 21 are electrically connected. And after sealing the vacuum vessel 10, the inside of the vacuum vessel 10 is exhausted by a rotary pump (not shown). The vacuum chamber 10 is evacuated until the internal pressure reaches about several Pa (for example, 1 Pa to 5 Pa). In this state, when a current in a predetermined direction is supplied to the Peltier element 12 and the pyroelectric crystal 11 that has been heated in advance is cooled, the pyroelectric crystal 11 is polarized, so that a positive charge is present on the upper surface and a negative charge is present on the lower surface. appear. At this time, since the upper surface (support base 22) of the pyroelectric crystal 11 is covered with the insulating grease 22, and only the tip of the needle 23 protrudes from the grease 22, the needle 23 faces the sample S and the fluorescent plate 15. A strong electric field is formed (state shown in FIG. 12A). Thereby, stray electrons near the needle 23 are accelerated toward the sample S ((b) of FIG. 12). Then, an electron beam that has passed through the sample S without being absorbed by the sample S or an electron beam diffracted by the sample S is incident on the fluorescent plate 15, and as a result, ZnS applied to the fluorescent plate 15 is excited. Light is emitted ((c) of FIG. 12).

  If the pyroelectric crystal 11 is continuously cooled by the Peltier element 12 and the temperature difference between the pyroelectric crystal 11 and the Peltier element 12 is eliminated, the heat transfer from the pyroelectric crystal 11 to the Peltier element 12, that is, the temperature change is eliminated. The polarization surface of the electrocrystal 11 is neutralized by floating charged particles in vacuum. For this reason, the electric field from the needle 23 toward the fluorescent plate 15 is eliminated, and the electron beam does not flow from the vicinity of the needle 23 toward the fluorescent plate 15. Therefore, the direction of the current supplied to the Peltier element 12 is switched to the opposite side, the pyroelectric crystal 11 is heated, and then the direction of the current supplied to the Peltier element 12 is switched again to cool the pyroelectric crystal 11. Thereby, as described above, an electron beam flows from the needle 23 toward the fluorescent plate 15, and a transmission electron beam image (or diffracted electron beam image) of the sample S can be observed.

  At this time, the magnification of the transmission electron beam image is determined by the ratio of the distance from the tip of the needle 23 to the sample S and the distance from the sample S to the fluorescent plate 15. For example, as shown in FIG. 3A, when the distance from the tip of the needle 23 to the sample S and the distance from the sample S to the fluorescent plate 15 is 1: 3, an enlarged image 4 times larger is obtained. As shown in (b), when the distance from the tip of the needle 23 to the sample S and the distance from the sample S to the fluorescent plate 15 are 1: 1, a double magnified image is obtained.

  The results of observing the copper mesh shown in FIG. 4 using the transmission electron microscope according to this example are shown in FIGS. 4A is a scanning electron microscope image (SEM image) of a copper mesh, and FIG. 4B is a substantial image. 5A to 5C show the transmission when the distance from the tip of the needle 23 to the fluorescent plate 15 is fixed to 55 mm, and the distance from the needle 23 to the copper mesh is changed to 5 mm, 3 mm, and 1 mm. FIGS. 6A to 6D show an electron beam image, in which the distance from the tip of the needle 23 to the copper mesh is fixed to 1 mm, and the distance from the copper mesh to the fluorescent plate is 15 mm, 30 mm, 45 mm, and 50 mm. The transmission electron beam image when changed is shown.

  5 and 6, after the vacuum vessel 10 is depressurized to 1 Pa, a voltage of 3 V is applied to the Peltier element 12 and the pyroelectric crystal 11 is heated for about 120 seconds to 100 ° C. The state of light emission of the fluorescent plate 15 during cooling is observed when the pyroelectric crystal 11 is cooled to −10 ° C. over 60 seconds by reversing the direction of the current flowing through the Peltier element 12.

  5 and 6, according to the transmission electron microscope according to the present embodiment, the transmission electrons having different magnifications can be changed by changing the distance from the tip of the needle 23 to the sample S or the distance from the sample to the fluorescent plate. It can be seen that a line image is obtained.

[Example 2]
FIG. 7 is a schematic configuration diagram of a transmission electron microscope according to the second embodiment of the present invention, and FIG. 8 is an enlarged view around the needle 23. The second embodiment is different from the first embodiment in that an electron lens 30 as a focusing lens is disposed between the sample S and the needle 23. Since other configurations are the same as those of the first embodiment, the same reference numerals are given and description thereof is omitted.
The electron lens 30 is mounted in the sample holder 14 so as to be positioned slightly below the sample S held by the sample holder 14. FIG. 9A is a longitudinal side view of the electronic lens 30, and FIG. 9B is a substantial image for explaining the size of the electronic lens 30. The electron lens 30 is a cylindrical part having a diameter of 20 mm and a height of 11 mm. The electron lens 30 includes a brass spacer 302 covered with a pure iron yoke 301 and a neodymium magnet 303 disposed at the center of the spacer 302. It is configured.

  Since the electron lens 30 is disposed between the needle 23 and the sample S, the electron beam emitted from the needle 23 is focused when passing through the electron lens 30 as shown in FIG. The The distance from the tip of the needle 23 to the electron lens 30 is set to 1 mm, and the distance from the tip of the needle 23 to the fluorescent plate 15 is set to 40 mm.

  FIG. 10A shows a transmission electron beam image (indicated by a white arrow in the figure) of the transmission electron microscope according to the present example when a copper mesh having a wire diameter of 100 μm and an opening of 150 μm is used as the sample S. A small circular image). FIG. 10B is a graph showing the emission intensity of the transmission electron beam image shown in FIG. The horizontal axis of this graph represents the distance (μm) from the origin when an arbitrary point located on a straight line passing through the center of the transmission electron beam image is the origin, and the vertical axis represents the emission intensity. In FIG. 8B, since light emission was observed in the range of 300 μm to 700 μm, it can be seen that the diameter of the transmission electron beam image was about 400 μm.

  On the other hand, FIG. 11A shows a transmission electron beam obtained by the transmission electron microscope (that is, the transmission electron microscope without an electron lens) according to the first example when the same copper mesh as that of FIG. (B) in FIG. 11 is a graph of the emission intensity of the transmission electron beam image. In FIG. 11B, since light emission was observed in the range of 2000 μm to 8000 μm, it can be seen that the diameter of the transmitted electron beam image without the electron lens 30 was about 6000 μm.

In addition, this invention is not limited to an above-described Example, For example, the following modifications are possible.
The electron lens may be disposed between the sample and the fluorescent plate as well as between the needle and the sample. The electron lens in this case functions as an objective lens or an imaging lens.
Although the transmission electron beam image has been described in the above embodiment, the same result can be obtained for the diffraction electron beam image.
In the above embodiment, the pyroelectric crystal is heated and cooled only by the Peltier element. However, the Peltier element may be used only for cooling the pyroelectric crystal, and a heater such as a heating wire may be used for heating the pyroelectric crystal. . In this case, the Peltier element and the heater constitute temperature changing means.

DESCRIPTION OF SYMBOLS 10 ... Vacuum vessel 101 ... Vertical tube part 102 ... Horizontal tube part 103 ... Window tube part 104, 105 ... Cover 106 ... Window plate 11 ... Pyroelectric crystal 12 ... Peltier element 13 ... Power supply device 14 ... Sample holder 15 ... Fluorescent plate DESCRIPTION OF SYMBOLS 16 ... Imaging device 17 ... Bellows duct 20 ... 1st rod 21 ... 2nd rod 22 ... Support body 23 ... Needle 24 ... Grease 30 ... Electron lens 301 ... Yoke 302 ... Spacer 303 ... Neodymium magnet S ... Sample

Claims (4)

e) a vacuum vessel;
f) a pyroelectric crystal disposed in the vacuum vessel; an insulator member having a lower dielectric constant than the pyroelectric crystal and covering one polarization surface of the pyroelectric crystal; and the pyroelectric crystal An electron beam emitter having a conductive needle having a protruding end protruding from the insulator member provided on one polarization surface, and a temperature changing means for changing the temperature of the pyroelectric crystal;
g) a sample holding unit that is arranged in the vacuum vessel and holds the sample so that the sample is positioned on an extension line of the protruding end of the needle, and is electrically connected to the other polarization surface of the pyroelectric crystal. A sample holder connected to and grounded,
h) an observation means for observing a projection image of the sample or a diffraction image of the sample by an electron beam emitted from the protruding end of the needle and transmitted through the sample;
A transmission electron microscope comprising: The transmission electron microscope according to claim 1, further comprising:
A focusing lens disposed between the electron beam emitting unit and the sample holding unit for focusing the electron beam emitted from the protruding end of the needle onto the sample held by the sample holding unit; A transmission electron microscope. The transmission electron microscope according to claim 1, further comprising:
A transmission electron microscope comprising an objective lens disposed between the sample holder and the observation means.   The transmission electron microscope according to any one of claims 1 to 3, wherein the temperature changing means includes a Peltier element in contact with the pyroelectric crystal and power supply means for supplying power to the Peltier element. .