US2281638A - Electron camera - Google Patents

Description

y 1941 T. w. SUKUMLYN 2,281,638

ELECTRON CAMERA Filed May 17, 1940 2 Sheets-Sheet l INV EN TOK %0/m5 Mia/70x4: REY

AT TO KN EY Patented May 5, 1942 UNITED STATES PATENT OFFICE azusas nsc'raon CAMERA J Thomas w. Snkmnlyn, I. Angeles, can.

Application May 11, 1940, Serial No. 335,145

11 Claims. (CL est-41.5)

This invention relates to an optical system for making a permanent record of an image by the aid of electrons.

In an ordinary light camera, it is essential to provide a photosensitive surface, usually formed by a silver salt emulsion. It is possible to affect this surface by ordinary light or even by radiation outside oi the visible spectrum. Such emulsions however have definite limitations. Thus it is difficult to obtain any image record for low intensities of radiation in any reasonably short period of exposure. For example, when distant stars are photographed it has been necessary to expose the photographic plate for such long intervals that definition is seriously affected, due to camera unsteadiness and changing atmospheric conditions.

It is one of the objects of this invention to produce an image record without the aid of a photo sensitive solution, and in such manner that the periods of exposure can be very greatly reduced.

Photosensitive emulsions necessarily have a grain structure, imposing a limit upon the resolving power. By the aid of the present inven-- tion, this disadvantage is overcome.

In order to accomplish these results, an electron image is formed, and this image is later caused to be made permanent.

It is accordingly another object of this invention to provide a photographic apparatus which utilizes electrons to produce a permanent image without the aid of a photosensitive emulsion.

This invention possesses many other advantages, and has other objects which may be made more easily apparent from a consideration of several embodiments of the invention. For this purpose there are shown a few forms in the drawings accompanying and forming part of the present specification. These forms will now be described in detail, illustrating the general principles of the invention; but it is to be understood that this detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

Figure 1 is a diagrammatic view of an apparatus incorporating the invention:

Fig. 2 is a detail section as seen on line 2-2 of Fig. l; and

Fig. 3 is a view similar to Fig. 1 showing a modifled form of the invention.

The electron camera includes in general, a vessel l adapted to be evacuated as by the aid of a connection 2 to a vacuum pump. This connection 2 may be controlled by a stop cock 3. Furthermore, in order to permit access to the interior of the vessel l, whenever it may be desired to remove or replace the member adapted to carry the image, a removable cap I is provided which may be appropriately sealed to one end of the vessel I.

The vessel I carries a tubular extension 5 through which photoelectrons are intended to pass to an insulation plate or member 8. This insulation plate may conveniently be made of glass or other translucent material whereby when the electron image on the member 8 is rendered permanent, this member may be utilized as a printing plate.

The photoelectrons may be caused to be emitted from a photoelectric layer "I, placed upon a transparent supporting medium 8, such as glass, which may be supported in any appropriate manner. This supporting medium 8 permits the passage of light therethrough to aflect the thin partly transparent photoelectric layer I. The vessel i is preferably made of transparent material, whereby an image may be focused upon the lower side of the supporting medium 8, as by the aid of a lens system diagrammatically illustrated at 8. However, it is to be understood that no light is permitted to enter the vessel I other than the light which passes through the lens system 9.

The image cast upon the supporting medium 8 causes emission oi photoelectrons from the layer 1 in conformity with the light pattern produced upon the medium 8. This stream of photoelectrons may be accelerated as by the aid of a grid structure l0 maintained positive with respect to the photoelectric cathode I, as by the aid of a source of direct current energy ll. Furthermore, I

the stream of photoelectrons is focused upon the surface of the insulation member 8 as by the aid of a coil I2 disposed around the extension 5 and shown as supplied with electrical energy from a battery It. Adjacent the upper surface of the member 6, a conducting plate or anode I l is provided maintained at a potential positive with respect to the cathode layer 1.

By appropriate choice of constants, it is possible to cause the photoelectrons to be retained upon the surface of member 6 in a pattern corresponding to the light pattern produced by the lens system 0 on the cathode structure 1-8. Since the plate or anode I4 is placed quite close to the member 6, a very considerable charge is built up on the member 6 corresponding to the electrons. The electric field caused by the collection of the electrons on-the member I is confined to 7 plate I4.

suiliciently energized are shown as deflected alon the space between the charge and the This pattern thus formed by the photoelectrons form,as by deposition of particles' in conformity with the position of the electrons on the member 8. For this purpose the member 6 is arranged to be moved to its dotted line position, opposite an extension I! of the vessel I. This movement can be so accomplished as not to disturb the electron pattern on the member i, the lens being obscured before this movement is made. In the new position, the plate 6 is in the path of moving particles of metal or other suitable material, produced in a manner to be hereinafter described. In order to facilitate movement of the the position of the member 6 without disturbing the seal of the vessel I, use may be made of a magnetic member 20 such as a permanent horseshoe magnet. This magnetic member influences the armature I8, since the armature is placed directly between the pole pieces of magnet 20.

By manually moving the magnet 20, the armature I8 is-caused to movewith the magnet 20.

Near the bottom of the extension I! is located a source of suitable vaporizable material, which may be metallic or other materials, located in a crucible 2|. This crucible is shown as adapted to be heated by heating element 22 energized from a source of electrical energy 22. The heat of the element 22 causes ionization of the-vaporizable material in crucible 2|. Further, the vaporized particles from crucible M can be charged positively as by the aid of the connection 24,1eading to the positive terminal of the source of electrical energy 25.

In order to avoid impartingtoo high a speed to metal particles or ions passing into the space near the plate 6, with consequent loss of control. the decelerating electrodes 26 and 21 of grid form may be utilized. These electrodes are maintained at potentials negative with respect to the charge of the material in crucible 2|. Those charged particles which are sufficiently energized to arrive in the field of control of the electric charge image on plate 8 will have paths indicated by the lines 28 and 29. Those which are not paths such as the lines 30 and SI.

Electrons may also be emitted from the material in crucible 2|. These, however. are arranged to be captured upon positively charged electrodes 32 and II which as shown in Fig. '2, are of arcuate cross-section with their respective concave surfaces facing each other. A transverse magnetic field produced by the coil 33 may also serve to deflect the electrons on to the plate 82.

The positively charged particles are captured by the negative charge on member 6 in accord- .ance with the electron pattern and are thus caused to reproduce in permanent form the image formed by the electrons. The seal may then be may be caused to be converted into permanent Then evacuation may. be effected by. the aid of the connection 2 and the process repeated.

Movement of member 6 away from beneath plate I4 causes the potential of the charge on member 8 to be increased, since work is thus performed in opposition to the attraction between the charges on member 8 and plate I4. Accordingly there is an enhanced effect between the iaporized particles and the electrons on member I v In the form just described, air is permitted to enter into the extension 5, whenever the plate 6 is removed. This may to some extent injure the photoelectric layer 1. In order to obviate this difliculty, a form of the invention may be utilized such as that illustrated in Fig. 3. The extension I5 in this figure carries apparatus entirely similar to that described in connection with Fig. 1. The extension 34, replacing extension I.-

is arranged somewhat differently so as to incorporate a stop cock plug 35 in the extension 34.

dividing the space in extension 34 into an upper .space 20 and a lower space 31.

through the restricted passageway 4| to aifect the member 8.

Below the plug 35 in the space 31 may be 10-- cated a number of focusing cylindrical anodes 42,

43, etc. maintained at progressively higher po'- tentials as the plug 35 is approached. The plug 35 itself may serve as a directing anode by appropriate connection 44.

In the compartment 38 may be located a supplemental focusing electrode 45, maintained at a still higher potential than the plug 25.

In this form of the invention, upon completion of the deposition of the vaporized particles from crucible 2I, the plug 35 may be turned to the closed position, maintaining the compartment 21 sealed. Then the cap 4 may be removed and the plate 6 taken out of the vessel I. may then be repeated, by placing a new member 8 within the vessel,, sealing the cap 4 and evacuating the vessel I through the connection 2.

If desired, an evacuating connection 4| may be provided for connection to a suction pump into the compartment 31, for ensuring proper vacuum conditions therein.

'What is claimed is:

1. In an electron camera, an evacuated vessel, means in said vessel, forming a photo-electric surface, means for focusing an image on said surface to cause emission of photoelectrons therefrom, a member in said vessel, made from insulation material, and capable of receiving said electrons, whereby a negative charge is formed on said member, electric focusing means i for causing said electrons to be distributed in a pattern upon said member in conformity with said image, and means forming a source of positively charged particles disposed within the vessel, spaced from said member and so located with respect thereto that the charge on said member is effective to attract particles from said source to the member, whereby said pattern is converted into permanent form.

2. In an electron camera, an evacuated vessel, means in said vessel, forming a photo-electric surface, means for focusing an image on said sur- The operation face to cause emission of photoelectrons therefrom, a member in said vessel, made from insulation material, and capable of receiving said electrons, whereby a negative charge is formed on said member, electric focusing means for causing said electrons to be distributed in a pattern upon said member in conformity with said image, means forming a source of positively charged particles disposed within the vessel, and means for moving said member out of the influence of the emitted photoelectrons, while retaining said pattern on the member, and into a position such that the charge on said member is eilective to attract particles from said source to the member, whereby said pattern is converted into permanent form.

3. In an electron camera, an evacuated vessel, means in said vessel, forming a photoelectric surface, means for focusing an image on said surface to cause emission of photoelectrons therefrom, a member in said vessel, made from insulation material, and capable of receiving said electrons, whereby a negative charge is formed on said member, electric focusing means for causing said electrons to be distributed in a pattern upon said member in conformity with said image, and means whereby said pattern is converted into permanent form, comprising a source of positively charged particles, so disposed within the vessel that the particles are attracted to said member, and means for collecting electrons from the path of said particles, comprising a positively charged plate adjacent said path.

4. In an electron camera, an evacuated vessel, means in said vessel, forming a photo-electric surface, means for focusing an image on said surface to cause emission of photoelectrons therefrom, a member in said vessel, made from insulation material, and capable of receiving said electrons, whereby a negative charge is formed on said member, electric focusing means for causing said electrons to be distributed in a pattern upon said member in conformity with said image, and means whereby said pattern is converted into permanent form, comprising means for moving said member out of the influence of the emitted photoelectrons, while retaining said pattern on the member, means for evaporating positively charged material onto said member, and means for collecting electrons from the path of said charged material, comprising a positively charged plate adjacent said path.

5. In an electron camera, an evacuated vessel, means in said vessel, forming a photoelectric surface, means for focusing an image on said surface to cause emission of photoelectrons therefrom, a member in said vessel, made from insulation material, and capable of receiving said electrons, whereby a negative charge is formed on said member, an electromagnetic coil for producing a magnetic field along the path of the photoelectrons. to cause the said photoelectrons to be distributed in a pattern upon said member in conformity with said image, and means forming a source of positively charged particles disposed within the vessel, spaced from said member and so located with respect thereto that the charge on said member is effective to attract particles from said source to the member, whereby said 'pattem is converted into permanent form.

6. In an electron camera, an evacuated vessel. means in said vessel, forming a photoelectric surface, means for focusing an image on said surface to cause emission of photoelectrons therefrom, a member in said vessel, made from insulation material, and capable of receiving said electrons, an electromagnetic coil for producing a magnetic field along the path of the photos-lemons, to cause the said photoelectrons to be distributed in a pattern upon said member in conformity with said image, and means whereby said pattern is converted into permanent form. comprising means for moving said member out of the influence of-said emitted photoelectrons, while retaining said pattern on the member, and means for evaporating positively charged particles onto said member while out of the influence of said emitted electrons.

7. In an electron camera, an evacuated vessel, means in said vessel, forming a photoelectric surface, means for focusing an image on said surface to cause emission of photoelectrons therefrom, a member in said vessel, made from insulation material, and capable of receiving said electrons, whereby a negative charge is formed on said member, electrodes in said vessel adapted to cause the said photoelectrons to be distributed in a pattern upon said member in conformity with said image, and means forming a source of positively charged particles disposed within the vessel, spaced from said member and so located with respect thereto that the charge on said member is effective to attract particles from said source to the member, whereby said pattern is converted into permanent form.

8. In an electron camera, an evacuated vesse means in said vessel, forming a photoelectric surface, means for focusing an image on said surface to cause emission of photoelectrons therefrom. a member in said vessel, made from insulation material, and capable of receiving said electrons, electrodes in said vessel adapted to cause the said photoelectrons to be distributed in a pattern upon said member in conformity with said image, and means whereby said pattern is converted into permanent form, comprising means for moving said member out of the influence of the emitted photoelectrons, while retaining said pattern on the member, and means for evaporating positively charged material onto said member while out of the influence of said emitted electrons.

9. In an electron camera, means forming a photoelectric surface, means for causing emission of the photoelectrons in a pattern from the surface, means forming a positively charged surface spaced from the photoelectric surface, an insulation member interposed in the space between the photoelectric surface and the positively charged surface, and adapted to receive and retain said photoelectrons, whereby a negative charge is formed on said member, means for moving said member away from the positively charged surface to increase the potential of the photoelectrons on said insulation member, and a source of positively charged particles arranged to be attracted to the member in its moved position, and to be attached thereto in conformity with the pattern.

10. In an electron camera, a vessel, a rotary stop cock for dividing the space in the vessel into two compartments, said vessel providing a seat for the stop cock, means forming a photoelectric surface in one of the compartments, and means comprising a positively charged plate, causing emitted photoelectrons to pass through the cock when it is in open position, and located in the other compartment.

11. In an electron camera, a vessel, a rotary 4 oneness stop cock ior dividing the space in the vessel into two compartments, ssid vessel providing s seat for the stop cock. menns iorming a photoeiectric surface in one o! the compartments, means causing emitted photoelectrons to pass through the cock when it is in open position, and locstedin the other compartment, means in the vessel for focusing the stream of photoelectrons, an insulation member capable of receiving and retaining the photoelectrons in s definite focused pattern, 10

on sold member. snd mesns forming s source said member is elective to attract particles from ssid source to the member, whereby said pattern is converted into permsnent form. t

moms w.

ssid photoelectrons iorming s negstive

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