JPH0616397B2 - Electron microscope image recording / reading device - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to an apparatus for recording and reading an electron microscope image, and more particularly to recording an electron microscope image with high sensitivity, and various kinds of image processing by electric signals. The present invention relates to a recording / reading device for reading an electron microscope image.

(Technical Background of the Invention and Prior Art) Conventionally, an electron microscope has been known in which an electron beam transmitted through a sample is refracted by an electric field or a magnetic field to obtain an enlarged image of the sample. As is well known, in this electron microscope, the electron beam transmitted through the sample forms a diffraction pattern of the sample on the back focal plane of the objective lens, and the diffraction lines interfere again to form a magnified image of the sample. Has become.
Therefore, if the magnified image is projected by the projection lens, the magnified image (scattered image) of the sample is observed, and if the back focal plane is projected, the magnified diffraction pattern of the sample is observed. If an intermediate lens is arranged between the objective lens and the projection lens, the above-mentioned magnified image (scattered image) or diffraction pattern can be optionally obtained by adjusting the focal length of this intermediate lens.

In order to observe the magnified image or diffraction pattern (hereinafter collectively referred to as a transmission electron beam image) formed as described above, conventionally, a photographic film is placed on the image plane of the projection lens to transmit a transmission electron beam. The image is exposed or an image intensifier is arranged to amplify and project the transmission electron beam image. However, photographic film has the disadvantage of low sensitivity to electron beams and troublesome development processing. On the other hand, when an image intensifier is used, the sharpness of the image is low and the image tends to be distorted. There is.

Further, for the transmission electron beam image as described above, gradation processing, frequency enhancement processing, density processing, for the purpose of making the image easier to see,
Image processing such as subtraction processing, addition processing, three-dimensional image reconstruction by Fourier analysis method, image analysis for binarization of the image and particle size measurement, and further diffraction pattern processing (crystal information analysis, (Lattice constant, transition, clarification of lattice defects, etc.) are often performed, but in such a case, conventionally, a microscope image obtained by developing a photographic film is read by a microphotometer and converted into an electric signal. The complicated work of converting the electric signal and performing A / D conversion of the electric signal and then processing the electric signal has been performed.

(Object of the Invention) The present invention has been made in view of the above circumstances, and carries an electron microscope image so that an electron microscope image can be recorded with high sensitivity and high image quality, and various kinds of processing are facilitated. It is an object of the present invention to provide an electron microscope image recording / reading device which can directly obtain the electric signal.

(Structure of the Invention) An electron microscope image recording / reading apparatus of the present invention is a stimulable phosphor sheet which is fixed to an image plane in a vacuum system of an electron microscope and accumulates energy of an electron beam transmitted through a sample, Excitation means for scanning the stimulable phosphor sheet with a light beam to emit the electron beam energy accumulated in the sheet as light, and photoelectrically detecting the light emitted from the stimulable phosphor sheet. A photodetector, and an erasing means for irradiating or heating the accumulative phosphor sheet after detection of the emitted light to release the energy remaining in the sheet. is there.

Specific examples of the material constituting the above-mentioned stimulable phosphor sheet include, for example, JP-A Nos. 55-12429 and 55-116.
No. 340, No. 55-163472, No. 56-1139.
No. 5, JP-A-56-104645 and the like can be particularly preferably used for the stimulable phosphor. That is, when a certain kind of fluorescent material is irradiated with radiation such as an electron beam, a part of the energy of this radiation is accumulated in the fluorescent material, and then the fluorescent material is irradiated with excitation light such as visible light, The fluorescent substance exhibits fluorescence (stimulated luminescence) according to the stored energy. A phosphor exhibiting such a property is called a stimulable phosphor.

A stimulable phosphor sheet usually comprises a support and a stimulable phosphor layer laminated on the support. This phosphor layer is formed by dispersing the phosphor in an appropriate binder, and when the phosphor layer is self-supporting, it can be accumulated by itself without using a support. It can be a fluorescent sheet.

As the excitation means, an excitation light source such as a He—Ne laser or a semiconductor laser or a heat ray source such as a CO ₂ laser, a galvanometer mirror, a polygon mirror (rotating polygon mirror),
An XY bidirectional deflecting means, which is a combination of a hologram scanner and an AOD (acousto-optic optical deflector), is used.

If an electron microscope image by a transmission electron beam is accumulated and recorded on the accumulative phosphor sheet arranged on the image plane of the electron microscope,
The stimulable phosphor sheet is scanned in both X and Y directions with excitation light such as visible light to generate fluorescence. This fluorescent light is stored on the side of the stimulable phosphor sheet opposite to the scanning side through an optical filter for cutting light of the excitation light wavelength or infrared rays and an optical shutter opened at the time of reading to the stimulable phosphor sheet. The signal is photoelectrically read by a photodetector such as a photomultiplier or a CCD provided in close contact with or in close proximity to obtain an electric signal corresponding to the transmitted electron beam image. In addition, it is preferable that the support of the stimulable phosphor sheet be provided with the function of the above optical filter. Using the electrical image signal thus obtained,
An electron microscope image can be displayed on a display such as a CRT, or can be permanently recorded as a hard copy, and the image signal can be temporarily stored in a magnetic tape, a magnetic disk, an optical disk, a magneto-optical disk, or the like. It can also be stored in a medium.

In the electron microscope image recording / reading device of the present invention, since the electron microscope image is accumulated and recorded on the accumulative phosphor sheet, it is possible to record the electron microscope image with high sensitivity, and therefore the electron microscope image. The electron beam exposure amount can be reduced, and the damage to the sample can be reduced. Further, according to the device of the present invention, since the electron microscope image is directly read as an electric signal, it becomes extremely easy to perform image processing such as gradation processing and frequency adjustment processing on the electron microscope image, and as described above. By processing the diffraction pattern, reconstructing a three-dimensional image, and binarizing the image, image analysis can be performed extremely easily and quickly by inputting the electric signal into the computer.

Further, since the stimulable phosphor sheet is fixed in the vacuum system and is scanned by the light beam in the X-Y directions, it is not necessary to break the vacuum system each time the reading operation is performed, and the stimulable phosphor sheet is also breached. The device can be made compact because there is no need to move the sheet in the sub-scanning direction, and the side of the accumulative phosphor sheet that is opposite to the side to be scanned is connected to the photodetector through an optical filter and an optical shutter. Since it can be provided in close contact with or close to, a large light receiving solid angle can be obtained, and S / N is improved.

Examples of stimulable phosphors utilized in the present invention include SrS: Ce, Sm, SrS: Eu, Sm, Th described in US Pat. No. 3,859,527.
A phosphor represented by a composition formula such as O ₂ : Er and La ₂ O ₂ S: Eu, Sm, Zn described in JP-A-55-12142.
S: Cu, Pb, BaO.xAl ₂ O ₃ : Eu [however, 0.8 ≦ x ≦ 10], and M ²⁺ O.xSi
O ₂ : A [M ²⁺ is Mg, Ca, Sr, Zn, C
d, or Ba, A is Ce, Tb, Eu, Tm,
Pb, Tl, Bi, or Mn, and x is 0.5 ≦
x ≦ 2.5] and a phosphor represented by a composition formula such as that described in JP-A-55-12143 (Ba).
_1-xy , Mg _x , Ca _y ) FX: aEu ²⁺ [wherein X is at least one of Cl and Br, and x and y
Is 0 <x + y ≦ 0.6 and xy ≠ 0, and a is
10 ⁻⁶ ≦ a ≦ 5 × 10 ⁻² ], the phosphor represented by the composition formula: LnO described in JP-A-55-12144.
X: XA (where Ln is at least one of L, Y, Gd, and Lu, X is at least one of Cl and Br, A is at least one of Ce and Tb, and x Is a phosphor represented by the composition formula of 0 <x <0.1, which is described in JP-A-55-12145 (Ba).
_1-x , M ^II _s ] FX: yA [where M ^II is Mg, C]
at least one of a, Sr, Zn, and Cd,
X is at least one of Cl, Br, and I, A
Is Eu, Tb, Ce, Tm, Dy, Pr, Ho, Nd,
At least one of Yb and Er, and x
Is 0 ≦ x ≦ 0.6, and y is 0 ≦ y ≦ 0.2], a phosphor represented by the composition formula, M ^II described in JP-A-55-160078.
FX xA: yLn [However, M ^II is Ba, Ca, S
at least one of r, Mg, Zn, and Cd,
A is BeO, MgO, CaO, SrO, BaO, Zn
O, Al ₂ O ₃ , Y ₂ O ₃ , La ₂ O ₃ , In ₂ O ₃ ,
SiO ₂ , TlO ₂ , ZrO ₂ , GeO ₂ , SnO ₂ ,
At least one of Nb ₂ O ₅ , Ta ₂ O ₅ , and ThO ₂ , and Ln is Eu, Tb, Ce, Tm, Dy, P
At least one of r, Ho, Nd, Yb, Er, Sm, and Gd, X is at least one of Cl, Br, and I, and x and y are each 5 × 10 5.
^-5 ≤ x ≤ 0.5 and 0 <y ≤ 0.2], described in JP-A-56-116777 (B).
a _1-x , M ^II _x ) F ₂ · aBaX ₂ : yEu, zA [M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium, and X is chlorine, bromine, and iodine. Of at least one of zirconium and scandium, a, x, y, and z
Are 0.5 ≦ a ≦ 1.25, 0 ≦ x ≦ 1, 10 ^{−6, respectively.}
≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 10 ⁻² ], which is described in JP-A-57-23673 (Ba).
^{_{1- x · M II x) F}} 2 · aBaX 2: yEu, zB [ However, M ^II is beryllium, magnesium, calcium,
At least one of strontium, zinc, and cadmium, X is at least one of chlorine, bromine, and iodine, and a, x, y, and z are 0.5 ≦ a ≦ 1.25 and 0 ≦, respectively. x ≦ 1, 10 ⁻⁶ ≦ y ≦ 2 ×
10 ⁻¹ , and 0 <z ≦ 10 ⁻² ], the phosphor represented by the composition formula, which is described in JP-A-57-23675 (Ba).
_1-x · M ^II _x ) F ₂ · aBaX ₂ : yEu, zB [M ^II is at least one of beryllium, magnesium, calcium, strontium, zinc, and cadmium, and X is chlorine, bromine, and iodine. At least one of them, A is at least one of arsenic and silicon, and a, x, y, and z are each 0.5 ≦ a ≦.
1.25, 0 ≦ x ≦ 1, 10 ⁻⁶ ≦ y ≦ 2 × 10 ⁻¹ , and 0 <z ≦ 510 ⁻¹ ], the phosphor having the composition formula of JP-A-58-206678. Ba described in the official gazette
_1-x M _{x / 2} L _{x / 2} FX: yEu ²⁺ [where M is Li,
Represents at least one alkali metal selected from the group consisting of Na, K, Rb, and Cs; L represents Sc,
Y, La, Ce, Pr, Nd, Pm, Sm, Gd, T
b, Dy, Ho, Er, Tm, Yb, Lu, Al, G
represents at least one trivalent metal selected from the group consisting of a, In, and Tl; X represents at least one halogen selected from the group consisting of Cl, Br, and I; and x represents 10 ^-2. ≦ x ≦ 0.5, y is 0 <y
≦ 0.1] A phosphor represented by the composition formula, BaF described in JP-A-59-27980.
X.xA: yEu ²⁺ [wherein X is at least one halogen selected from the group consisting of Cl, Br, and I; A is a calcined product of a tetrafluoroboric acid compound; and x is 10 ⁻⁶ ≦ x ≦ 0.1, y is 0 <y ≦
A phosphor represented by a composition formula of 0.1], and BaF described in JP-A-59-47289.
X · xA: yEu ²⁺ [wherein X is at least one halogen selected from the group consisting of Cl, Br, and I; A is hexafluorosilicic acid, hexafluorotitanic acid, and hexafluorozirconic acid; It is a calcined product of at least one compound selected from the group of hexafluoro compounds consisting of salts of monovalent or divalent metals; and x is 10 ⁻⁶ ≦ x ≦ 0.1 and y is 0 <y ≦ 0.1. And a BaF described in JP-A-59-56479.
X · xNaX ′: aEu ²⁺ [where X and X ′ are
At least one of Cl, Br, and I, and x and a are 0 <x ≦ 2 and 0 <, respectively.
a ≦ 0.2], a phosphor represented by the composition formula: M ^II F described in JP-A-59-56480.
X · xNaX ′: yEu ²⁺ : zA [where M ^II is B
at least one alkaline earth metal selected from the group consisting of a, Sr, and Ca; X and X ′ are each at least one halogen selected from the group consisting of Cl, Br, and I; A is , V, Cr, M
at least one transition metal selected from n, Fe, Co, and Ni; and x is 0 ≦ x ≦ 2 and y is 0.
<Y ≦ 0.2, and z is 0 <z ≦ 10 ⁻² ], and a phosphor represented by the composition formula: M ^II FX described in Japanese Patent Application Laid-Open No. 59-75200 by the present applicant.・ AM ^I X '・ bM' ^II X " ₂・ cM
^III X ₃ · xA: yEu ²⁺ [However, M ^II is Ba, S
at least one alkaline earth metal selected from the group consisting of r and Ca; M ^I is Li, Na, K, R
b, and at least one alkali metal selected from the group consisting of Cs, M ^'II is at least one trivalent metal selected from the group consisting of Be and Mg; M
^III is at least one trivalent metal selected from the group consisting of Al, Ga, In, and Tl; A is a metal oxide; X is at least one selected from the group consisting of Cl, Br, and I Halogen; X ′, X ″,
And X ″ ′ is at least one halogen selected from the group consisting of F, Cl, Br, and I; and a is 0 ≦ a ≦ 2, b is 0 ≦ b ≦ 10 ⁻² , and c is 0 ≦
c ≦ 10 ⁻² and a + b + c ≧ 10 ⁻⁶ ; x is 0 <
x ≦ 0.5, y is 0 <y ≦ 0.2], a phosphor represented by the composition formula: M ^II X ₂ · aM ^II X ′ described in Japanese Patent Application No. 58-193161. ₂ : xEu ²⁺ [wherein M ^II is at least one alkaline earth metal selected from the group consisting of Ba, Sr and Ca; X
And X ′ is at least one halogen selected from the group consisting of Cl, Br and I, and X ≠ X ′; and a is a numerical value in the range of 0.1 ≦ a ≦ 10.0, x is a numerical value in the range of 0 <x ≦ 0.2], and the like, and the like.

However, the stimulable phosphor used in the present invention is not limited to the above-mentioned phosphor, and when irradiated with excitation light after being irradiated with an electron beam, it is a phosphor showing stimulable luminescence. It may be any one.

The accumulative phosphor sheet using these phosphors may have a protective layer. If this protective layer has conductivity, it is possible to prevent charge-up due to an electron beam. Further, the phosphor layer may be colored with a pigment or a dye as disclosed in JP-A-55-163500.

Embodiments Embodiments of the present invention will be described in detail below with reference to the drawings.

FIG. 1 schematically shows an electron microscope image recording / reading apparatus according to an embodiment of the present invention. The body 1a of the electron microscope 1 includes an electron gun 3 for emitting an electron beam 2 having a uniform speed,
At least one focusing lens 4 including a magnetic lens, an electrostatic lens, and the like for narrowing down the electron beam 2 on the sample surface, and a sample table 5
And an objective lens 6 similar to the focusing lens 4 and a projection lens 7. Sample 8 placed on the sample table 5
The electron beam 2 that has passed through is refracted by the objective lens 6 to form an enlarged scattered image 8a of the sample 8. This enlarged scattered image 8a is image-projected by the projection lens 7 on the image plane 9 (8b in the figure).

An electron microscope image recording / reading device 10 according to the present invention is arranged below the mirror body portion 1a. This electron microscope image recording / reading apparatus 10 includes a two-dimensional sensor (hereinafter referred to as a stimulable phosphor sheet 11) composed of a stimulable phosphor fixed to the image forming surface 9 in the mirror body portion 1a, and excitation. A photomultiplier 15 arranged so as to face the stimulable phosphor sheet 11 through an exciting means including a light source 12 and an optical scanning system 13 and a translucent window 14 provided on a peripheral wall of the mirror body portion 1a. When,
And an erasing light source 16.

The stimulable phosphor sheet 11 is formed by layering the stimulable phosphor as described above on a transparent support. The excitation light source 12 is composed of, for example, a He-Ne laser, a semiconductor laser, etc., and the optical scanning system 13 is composed of first and second optical deflectors 13a and 13b and a fixed mirror 13c.
Known optical deflectors such as a galvanometer mirror, a polygon mirror, a hologram scanner, and an AOD may be used as the first and second optical deflectors 13a and 13b, respectively. The excitation light beam 12a emitted from the excitation light source 12 is deflected by the first optical deflector 13a and
Is deflected by the optical deflector 13b in the direction perpendicular to the above-mentioned deflection direction (direction of arrow A in the figure), passes through the transparent window 21 in which lead glass or the like is fitted, and enters the mirror body portion 1a. The light is reflected by the fixed mirror 13c and is incident on the stimulable phosphor sheet 11. In this way, the stimulable phosphor sheet is scanned by the light beam in both X and Y directions.
Although not shown, the excitation light beam 12a emitted from the excitation light source 12 is passed through a filter that cuts the wavelength region of the stimulated emission light, the beam diameter is adjusted by a beam expander, and then the optical deflectors 13a and 13b are adjusted. It is preferable that the light beam is deflected by the laser beam and then passed through the fθ lens to have a uniform beam diameter and is incident on the stimulable phosphor sheet. The erasing light source 16 emits light included in the excitation wavelength region of the stimulable phosphor sheet 11. A mirror 17 is provided between the second optical deflector 13b and the fixed mirror 13c so as to be able to take a position that enters the optical path of the excitation light beam 12a and a position that deviates from the optical path.
The erasing light emitted by the erasing light source 16 is condensed by a lens 18, and if the mirror 17 is set at a position to enter the optical path of the excitation light beam 12a, the erasing light is reflected by the mirror 17 and the fixed mirror 13c to accumulate. The phosphor sheet 11 is entirely illuminated. A shutter 19 capable of blocking the electron beam 2 is provided in the mirror body portion 1 a between the objective lens 7 and the stimulable phosphor sheet 11. Then, the translucent window 14 is fitted with a glass 20 provided with an optical filter that transmits only stimulated emission light (described in detail later) emitted from the stimulable phosphor sheet 11 and removes the excitation light beam 12a. Has been done. The interior of the mirror portion 1a is vacuumed by a known means such as a vacuum pump during operation of the electron microscope, including the portion where the stimulable phosphor sheet 11 is arranged, as in a normal electron microscope. Maintained in a state.

Next, recording and reading of an electron microscope image by the electron microscope image recording / reading apparatus 10 having the above configuration will be described in detail. When the shutter 19 is opened (state shown in FIG. 1), the sample 8 is placed on the accumulative phosphor sheet 11 arranged on the imaging lead 9.
The energy of the electron beam 2 carrying the magnified scattered image 8b is accumulated. It is preferable that the optical shutter 24 be closed during the exposure of the electron beam. Then, the shutter 19 is closed and the optical shutter 24 is opened, and subsequently, the excitation light beam 12a deflected in both the X and Y directions as described above is incident on the sheet 11. The excitation light beam 12a thus deflected causes the stimulable phosphor sheet 11 to move to 2
Scanned dimensionally, the sheet 11 emits stimulated emission light having an intensity corresponding to the electron beam energy level. This stimulated emission light is received from the back side of the sheet 11 through the glass 20 provided with the optical filter for removing the excitation light beam 12a by the photomultiplier 15, and the amount of the stimulated emission light is photoelectrically read.

The electric signal obtained by reading the stimulated emission light by the photomultiplier 15 is transmitted to the image processing circuit 22, subjected to necessary image processing, and then sent to the image reproducing device 23.
The image reproducing device 23 may be a display such as a CRT or a recording device for performing optical scanning recording on a photosensitive film. By thus outputting an image using an electric signal corresponding to the amount of stimulated emission light, the enlarged scattered image 8b carried by the stimulated emission light is reproduced.

FIG. 3 shows an image scanning recording device as an example of the image reproducing device 23. The photosensitive film 130 is moved in the sub-scanning direction of arrow Y, and the laser beam 131 is moved.
Main scanning in the X direction on the photosensitive film 130, and the laser beam 131 is modulated by the A / O modulator 132 based on the image signal from the image processing circuit 22 to form a visible image on the photosensitive film 130. Is formed.

Here, the screen size of the visible image formed on the photosensitive film 130 is set to be larger than the size of the image forming surface 9 (that is, the storage recording area on the two-dimensional sensor), and the enlarged scattered image 8b is formed. The image is reproduced while being enlarged as compared with that on the image plane 9. When the stimulable phosphor sheet 10 is used, the enlarged scattered image 8b is reproduced with high sharpness, so that even if it is enlarged in this way, a reproduced image of sufficiently good quality can be obtained. Therefore, a small size can be used as the stimulable phosphor sheet 10, and a small size of the photoelectric converter 15 can also be used with it, and the device can be made compact as a whole.

In order to output an image enlarged by the image scanning recording apparatus as shown in FIG. 3, the scanning line density is stored in the stimulable phosphor sheet 1.
It may be coarser than the read scanning line density when the image information is obtained from 0. In order to obtain sufficient image information from a small size accumulative phosphor sheet as in the present invention, the read scan line density is 10 pixels / mm or more, particularly 15 pixels / mm-10.
It is preferable to set it in the range of 0 pixel / mm, but the scanning line density for reproducing image recording is rougher than this, and preferably the reading scanning line density used in the range of 5 pixels / mm to 20 pixels / mm. If a scanning line density coarser than that is selected, a magnified reproduced image can be obtained without deterioration in image quality.

In the above description, the optical filter, the optical shutter, and the photomultiplier are arranged outside the vacuum system in this order close to the side opposite to the scanning side of the two-dimensional sensor. It may be arranged inside.

After the above-mentioned image reading is completed, the optical shutter 24 provided between the photomultiplier 15 and the optical filter glass 20.
Is closed, the mirror 1 is set in a position to enter the optical path of the excitation light beam 12a, and the erasing light source 16 is turned on. As a result, the surface of the sheet 11 is irradiated with the erasing light emitted by the erasing light source 16. Even when the stimulable phosphor sheet 11 is irradiated with the excitation light beam 12a as described above, not all the electron beam energy accumulated in the sheet 11 is emitted, but an afterimage may remain. However, if the stimulable phosphor sheet 11 is irradiated with erasing light as described above, the afterimage is erased, and the stimulable phosphor sheet 1 is erased.
1 becomes reusable. Also, due to this erasing irradiation, ²²⁶ Ra contained as an impurity in the phosphor of the sheet 11 was detected.
Noise components due to radioactive elements such as are also emitted. Examples of the erasing light source 16 include, for example, JP-A-56-11392.
A tungsten lamp, a halogen lamp, an infrared lamp, a xenon flash lamp, a laser light source, or the like, as shown in the above publication, can be optionally used. The reading excitation light source 12 may also be used for erasing.

As described above, the magnified scattered image 8b is displayed on the stimulable phosphor sheet 11
When the image is stored and recorded in (1), it is necessary to focus the enlarged scattered image 8b correctly. This focusing is performed by the shutter 19 as in the conventional electron microscope.
A fluorescent screen is arranged in the vicinity of, and an enlarged scattered image 8b of the electron beam 2 is displayed on the fluorescent screen, and the mirror portion 1a is displayed.
This can be done by operating the focusing knob (not shown) of the electron microscope while observing the displayed image through the observation window provided on the peripheral wall of the. Further, the enlarged scattered image 8b recorded on the stimulable phosphor sheet 11 as described above is reproduced as an image for focusing on the image reproducing device 23, and the reproduced image is observed to judge the focus state, and the judgment result thereof. Based on the above, the focus adjustment knob may be operated to correct the focus. In this case, after the focusing image is erased as described above, the magnified scattered image 8b in focus is recorded again on the stimulable phosphor sheet 11 as an image for observing the sample. You can read it.
When the focusing image is recorded on the stimulable phosphor sheet 11 and reproduced by the image reproducing device 23 as described above, the focusing image does not need to be output in the same size as the final output image, Irradiation of excitation light and detection of stimulated emission light may be performed on a part of the image area of the final output image, and an image of only that part may be output. This shortens the time required to reproduce the focusing image and improves the efficiency of the focusing work.
In addition, when the image for focus adjustment is reproduced, even if the image is read in a larger pixel unit than that in the reproduction of the final output image, the same effect as described above can be obtained.

The image for focusing can be used not only for focusing the enlarged scattered image 8b, but also for determining the visual field range of the final output image.

If a shutter is provided on the arrow between the sample 8 of the mirror body portion 1a and the electron gun 3 so as to block the electron beam 2 except during photographing, the sample 8 is further prevented from being damaged.

Although the embodiment for recording and reproducing the enlarged scattered image of the sample 8 by the transmitted electron beam has been described above, the present invention can also be applied to record and reproduce the diffraction pattern of the sample described above. FIG. 2 shows how the diffraction pattern 8c of the sample 8 is recorded. In this embodiment, the electron microscope 40 is provided with an intermediate lens 41 between the objective lens 6 and the projection lens 7, and the diffraction pattern 8c of the sample 8 formed on the back focal plane of the objective lens 6 is Intermediate lens 41 and projection lens 7 focused on the back focal plane
Is enlarged and projected on the image plane 9. Also in this case, the stimulable phosphor sheet 1 as a two-dimensional sensor is formed on the image plane 9 as a two-dimensional sensor.
If 1 is arranged, an enlarged image of the diffraction pattern 8c by the transmitted electron beam 2 is accumulated and recorded on the sheet 11. The accumulated and recorded diffraction pattern 8c can be taken out in exactly the same manner as described with reference to FIG. 1, and the read image can be displayed on the CRT or reproduced as a hard copy. .

Furthermore, in order to eliminate the influence of fluctuations in recording conditions or to obtain an electron microscope image with excellent observability, recording of a transmission electron beam image (enlarged scattered image or enlarged diffraction pattern) accumulated and recorded on the stimulable phosphor sheet 11 is recorded. The recording pattern determined by the state, the properties of the sample, the recording method, etc. is grasped prior to the output of the visible image for observing the sample, and the reading gain of the photomultiplier 15 is appropriately determined based on the grasped accumulated record information. It is preferable to adjust the value to a proper value or perform appropriate signal processing. Further, it is required to solve the recording scale factor so that the resolution is optimized according to the contrast of the recording pattern in order to obtain a reproduced image with excellent observability.

As described above, as a method of grasping the accumulated record information of the stimulable phosphor sheet 11 prior to the output of the visible image, for example, the method disclosed in JP-A-58-89245 can be used. That is, by using the excitation light having an energy lower than the energy of the excitation light to be irradiated in the reading operation (main reading) for obtaining a visible image for observing the sample 8, the accumulative phosphor is preliminarily preceded by the main reading. A read operation (pre-reading) for grasping the accumulated record information accumulated and recorded on the sheet 11 is performed, the accumulated record information of the sheet 11 is grasped, and then the main reading is performed, and the reading gain is adjusted based on the pre-read information. It can be adjusted appropriately, the recording scale factor can be determined, or appropriate signal processing can be performed.

Further, in order to appropriately adjust the reading gain or the recording scale factor as described above, or to perform appropriate signal processing, in addition to the above-described preparatory operation, the above-mentioned focusing image is displayed on a display such as a CRT. Play,
While observing this display, an appropriate reading gain, recording scale factor, or signal processing condition is preliminarily determined in an interactive manner, and when the final output image is reproduced, the reading gain, recording scale factor, or signal which has been preliminarily determined is reproduced. Image reading and signal processing may be performed based on processing conditions.

(Effect of the Invention) As described in detail above, according to the device of the present invention, the electron microscope image is accumulated and recorded on the stimulable phosphor sheet, so that the electron microscope image can be recorded with high sensitivity. Therefore, the electron beam exposure of the electron microscope can be reduced,
Damage to the sample can be reduced. In addition, since the recorded image can be displayed on the CRT or the like immediately with high sensitivity, a clear monitor image can be obtained by using the reproduced image as a monitor image for focusing of an electron microscope, which is unprecedented. The focus can be adjusted with the low electron beam exposure that was possible.

Moreover, since the electron microscope image is read as an electric signal in the device of the present invention, it becomes extremely easy to perform image processing such as gradation processing and wave number enhancement processing on the electron microscope image, and the diffraction pattern as described above is obtained. Image processing such as processing, three-dimensional image reconstruction, and image binarization can be performed much easier and faster than before by inputting the electric signal to the computer.

Further, since the accumulative phosphor sheet for accumulating and recording electron microscope images can be reused by subjecting it to light irradiation, heating, etc., according to the present invention, when a conventional silver salt photographic system is adopted. It is possible to reproduce the electron microscope image more economically than the above.

Further, since the stimulable phosphor sheet is fixed in the vacuum system and is scanned by the light beam in the X-Y directions, it is not necessary to break the vacuum system each time the reading operation is performed, and the stimulable phosphor sheet is also breached. Scanning can be made compact because there is no need to move the sheet in the sub-scanning direction, and the side of the accumulative phosphor sheet that is opposite to the side to be scanned is connected to the photodetector through an optical filter and an optical shutter. Since it can be provided in close contact with or close to, a large light receiving solid angle can be obtained, and S / N is improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the device of the present invention, FIG. 2 is a schematic diagram showing another example of an electron microscope which can be combined with the device of the present invention, and FIG. 3 is an electron based on the method of the present invention. It is a schematic diagram showing an example of an image reproducing device which reproduces a microscope image. 1, 40 ... Electron microscope, 2 ... Electron beam 8 ... Sample, 9 ... Image plane of electron microscope 10 ... Electron microscope image recording / reading device 11 ... Accumulative phosphor sheet 12 ... Excitation light source , 12a ... Excitation light beam 13 ... Optical scanning system, 15 ... Photomal 16 ... Erase light source

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsu Noguchi 798 Miyadai, Kaisei-cho, Ashigarashie-gun, Kanagawa Fuji Photo Film Co., Ltd. (56) Reference JP 58-122500 (JP, A) JP 48 -31684 (JP, B1)

Claims (2)

[Claims] 1. A stimulable phosphor sheet which is fixed to an image plane in a vacuum system of an electron microscope and accumulates energy of an electron beam transmitted through a sample, and the stimulable phosphor sheet by a light beam. Excitation means for emitting the electron beam energy accumulated in the sheet as light by scanning in the XY direction; a photodetector for photoelectrically detecting the emitted light from the accumulative phosphor sheet; An electron microscope image recording / reading apparatus comprising: an erasing means for irradiating or heating the accumulative phosphor sheet after detecting the emitted light to release the energy remaining in the sheet. 2. The photodetector has a side that scans a light beam of the stimulable phosphor sheet through an optical filter that cuts light having an excitation light wavelength or infrared rays and a shutter that opens when reading and closes when erasing. The electron microscope image recording / reading apparatus according to claim 1, wherein the two are closely attached to or close to each other.