US2408287A - Electron microscope - Google Patents
Electron microscope Download PDFInfo
- Publication number
- US2408287A US2408287A US520610A US52061044A US2408287A US 2408287 A US2408287 A US 2408287A US 520610 A US520610 A US 520610A US 52061044 A US52061044 A US 52061044A US 2408287 A US2408287 A US 2408287A
- Authority
- US
- United States
- Prior art keywords
- screen
- electron
- fluorescent
- image
- electron microscope
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000003287 optical effect Effects 0.000 description 9
- 238000010894 electron beam technology Methods 0.000 description 7
- 239000002245 particle Substances 0.000 description 5
- 230000000694 effects Effects 0.000 description 4
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 3
- 239000010410 layer Substances 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 230000004048 modification Effects 0.000 description 3
- 238000012986 modification Methods 0.000 description 3
- 239000002356 single layer Substances 0.000 description 3
- 239000011521 glass Substances 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 description 1
- 241000206607 Porphyra umbilicalis Species 0.000 description 1
- 241001486234 Sciota Species 0.000 description 1
- 241000282890 Sus Species 0.000 description 1
- 241000282898 Sus scrofa Species 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000001143 conditioned effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000003247 decreasing effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000001493 electron microscopy Methods 0.000 description 1
- 238000009499 grossing Methods 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- 239000012212 insulator Substances 0.000 description 1
- 238000011835 investigation Methods 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 239000000523 sample Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J37/00—Discharge tubes with provision for introducing objects or material to be exposed to the discharge, e.g. for the purpose of examination or processing thereof
- H01J37/02—Details
- H01J37/22—Optical, image processing or photographic arrangements associated with the tube
- H01J37/224—Luminescent screens or photographic plates for imaging; Apparatus specially adapted therefor, e. g. cameras, TV-cameras, photographic equipment or exposure control; Optical subsystems specially adapted therefor, e. g. microscopes for observing image on luminescent screen
Definitions
- :It is an .iobject of my invention to provide im- "proved' means by which very thin fluorescent Patented Sept. 24, 1946 Charles II.
- the present invention relates to electron optical apparatus particularly adapted for themiOlU- scopic examination of electron pervious objects. It is .an'object of the invention to provide a new and improved fluorescent screen for an electron microscope. v p f It, is known that objects may be microscopically examined by the rays of an electron beam which transra'diates the object, the beam' passing throughithe object and in'this passage being providedwith thelch'aracteristics thereof.
- Such an "electron beam may be refracted by appropriately conditioned fields and the beam may be impinged upon a fluorescent screen; an image being constructed on. the screen, in accordance withthe characteristics given to 'the'bea'm in its passage through the object. It that there are two fundamental limitations in the use of fluorescent screenin electron microscopy where an electron beamjis impin ed upon and passes through the screen; These limitations are thecsize of thejphosphor or fluorescent parhasbeen observed.
- Fig. 1 represents diagrammatically an end section of an electron optical system'employing my invention
- Fig. 2 is a cross-sectional view showing'the fluorescent"scre'en supporting arrangement of the invention.
- FIG. 1 Referring to Figs. 1" and 2 jointly, there is shown an electron microscope 'comprising an elongatedvacuum-t'ight container H] of a tubular metal construction; Atone end of thecontainer, there isi'provided a glass insulator I l which serves to support an electron source in" the :form of a filamentary cathode-121 The cathode I2 is surrounded by a tubularmetal member'lfi which confines the" emitted electrons to a "narrow beam and is cooperatively positioned with 'res'pect'to an M which is in contact with I the metal envelope part l0.- The opposite end of ticles and the physical thickness'of the screen.
- Improved magnification may be attained, therefore; if asufliciently thin fluorescent to incomplete coverage of a screen surface delescreen, preferably consisting of: a single layer of 1 teriously afiecting satisfactoryimaging of the screens may be successfullyemplo'yed in electron optical studies or .objects.
- the beam theen'velo'pe I0 is sealed by a glass window I5.
- the envelope l0 and the apertured electrode I4 are maintained at "g'round-potentialand the cathode is maintained at a high negative potential, for example; being connected to 'a potential source "l1 "so that electrons the cathode are promoted axially of the container-with'the objector producing a visible image on the fluorescent screen l8.
- object supl9.c In the intended use of the apparatus, this means is to-be employed as a support for an object to be transradiated *by an electron beam, the beam being passed-through the object and in the passage assuming the characteristics of the object.
- a supporting structure may be provided in connection means l9 and may appropriate clamps or other an object with its surface, in exposed position to the electron beam20.
- I v V In order that the electron beam, after modification in accordance with the structural character of the object under investigation as the beam be caused to provisible image ofthe object in the intended use of the micro- 20, after passing vide an enlarged accordance with through the object, is caused to pass through an electron lens system of known character.
- the lens system is illustrated as of the electrostatic type, although a lens system of the magnetic type may be employed.
- the lens system comprises a series of three diaphragms, numbered 22-24, inclusive.
- the diaphragms 22 and 24 are maintained at the potential of the casing H1, that is, at ground potential and the intermediate diaphragm biased to cathode potential through a connection 25 which is brought into the microscope enclosure through an insulating bushing 26.
- lens fields are established between these diaphragms which have the eifect of refracting the electron beam in a manner analogous to the refraction of a light beam by an optical lens. Additional lens fields may be employed in the electron microscope where so desired.
- Means are provided for optical magnification of the image formed on the fluorescent screen I6 and this means is represented conventionally as an o tical lens 29 throu h which the beam of vis ble radiation 28. projected throu h window I from fluorescent screen I6. is caused to p ss.
- T e fluorescent screen I 5 shown in plan View in Fig. 2 comprises a frame member 30 wh ch Inav b i her circular or recta'n nlar in sha e and which su orts a trans are t window 3
- the coat ng 32 consists of a minimum number of lavers of s ll particles Of'a su table hos hor.
- the frame 30 is sus ended within member In by means of a s t of swine members 33 which provirie a good cond ctive connection, between screen l6 and tu e H).
- a rod m mber 35 which extends throu h an o ening 35 in tube and passes throu h a bellows device 31.
- the bellows 31 providing a seal across opening 36.
- the member 35 a a nnr irm exten in pwterio-rlv of the e]- lows 31 by wh ch motion may be im arted to screen [6 to produce lateral movement of this screen.
- a plurality of guide members 39 are attached to the inner surface of co tainer Ill.
- the uide members 39 may be prov ded with slots or fin ers at o e of their ends and the screen I 6 may b restrained by these fingers from axial movement and yet perm tted to move in a plane perpendicular to the axis of the container I0.
- the screen 16 may be moved laterally and the eifect of any kind of screen irregularities, such as holes, dirt specks, and similar defects in the phosphor coating on screen l6 which would normally produce distortion in optically enlarged images on the fluorescent screen I 6 is eliminated, Since the electron beam 20 always bombards the same points in space, as the screen I6 is shifted in a plane perpendicular to the beam, the effect of smoothing out all the irregularities of the above-mentioned type in the screen structure is obtained.
- any kind of screen irregularities such as holes, dirt specks, and similar defects in the phosphor coating on screen l6 which would normally produce distortion in optically enlarged images on the fluorescent screen I 6
- a fluorescent screen in an electron microscope of the type described above, a fluorescent screen may be employed. which is made up of a single layer of fluorescent particles; Such a screen usually is not suitable for electron microscopic examinations, since the coverage of the screen under such conditions is only about 60% complete. In the normal microscope, therefore, more effective coverage of the screen surface is obtained by adding additional layers of fluorescent material. In a microscope, however, in which lateral shaking of the screen is provided, a single layer of fluorescent particles may be employed and the shaking produces the effect of a completely covered very thin screen having reucked light output because of the decreased number of fluorescent particles.
- An electron microscop comprising an evacuated container having a fluorescent screen positioned therein, means for projecting a beam of electrons upon said screen, means for supporting an object to be examined in the path of said beam, and means for vibrating said screen in a plane substantially transverse to said beam to reduce blurring of the image of said object produced on said screen.
- An electron microscope system comprising an evacuated container having a transparent wall, a fluorescent screen supported within said container in front of said wall, means for probe vibrated screen, means external of said container for producing optical enlargement of the' image on said screen, and means for vibrating said screen in a plane substantially transverse to said beam to reduce blurring of said enlarged image due to said beam to reduce 5.
Landscapes
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
BE480178D BE480178A (de) | 1944-02-01 | ||
US520610A US2408287A (en) | 1944-02-01 | 1944-02-01 | Electron microscope |
GB2366/45A GB588119A (en) | 1944-02-01 | 1945-01-30 | Improvements in and relating to electron microscopes |
FR948342D FR948342A (fr) | 1944-02-01 | 1947-06-25 | Perfectionnements aux écrans de projection en général, et en particulier à ceux des microscopes électroniques |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US520610A US2408287A (en) | 1944-02-01 | 1944-02-01 | Electron microscope |
Publications (1)
Publication Number | Publication Date |
---|---|
US2408287A true US2408287A (en) | 1946-09-24 |
Family
ID=24073344
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US520610A Expired - Lifetime US2408287A (en) | 1944-02-01 | 1944-02-01 | Electron microscope |
Country Status (4)
Country | Link |
---|---|
US (1) | US2408287A (de) |
BE (1) | BE480178A (de) |
FR (1) | FR948342A (de) |
GB (1) | GB588119A (de) |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2444700A (en) * | 1945-10-26 | 1948-07-06 | Rca Corp | Method of operating electron guns |
US3150255A (en) * | 1962-07-05 | 1964-09-22 | Philips Electronic Pharma | Viewing window for electronoptical devices |
US3397336A (en) * | 1967-03-06 | 1968-08-13 | Raytheon Co | Target rotatable by tubular member of deformable, shape-retaining material |
-
0
- BE BE480178D patent/BE480178A/xx unknown
-
1944
- 1944-02-01 US US520610A patent/US2408287A/en not_active Expired - Lifetime
-
1945
- 1945-01-30 GB GB2366/45A patent/GB588119A/en not_active Expired
-
1947
- 1947-06-25 FR FR948342D patent/FR948342A/fr not_active Expired
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2444700A (en) * | 1945-10-26 | 1948-07-06 | Rca Corp | Method of operating electron guns |
US3150255A (en) * | 1962-07-05 | 1964-09-22 | Philips Electronic Pharma | Viewing window for electronoptical devices |
US3397336A (en) * | 1967-03-06 | 1968-08-13 | Raytheon Co | Target rotatable by tubular member of deformable, shape-retaining material |
Also Published As
Publication number | Publication date |
---|---|
BE480178A (de) | |
FR948342A (fr) | 1949-07-28 |
GB588119A (en) | 1947-05-14 |
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