US2409454A - Electronic device - Google Patents

Description

o@ 15 1946- A. G. THOMAS ELECTRONIC DEVICE Filed Jan. 27, 1944 ililiilllliliillllll| E. f.. G QL Patented ct. 15, 1946 UNITED STATES PATENT OFFICE 2,409,454 ELECTRONIC DEVICE Albert G. Thomas, Lynchburg, Va.

Application January 27, 1944, serial No. 519,924

(ci. 25o-41.5)

21 Claims.

This invention relates to electronic devices and particularly to reproducers for copying letters, maps, drawings, photographs and the like.

Many reproclucers have been marketed depending upon various processes Such as gelatin images, photographic reproductions, blueprinting, and others. All kof these methods are relatively slow, however, and are somewhat cumbersome in operation; besides requiring liquid chemicals or vapors for development. In contrast, my electronic reproducer is fast, requires no chemicals, and provides accurate copies in small or large quantities in a minimum of time.

A primary object is to provide an electronic reproducer that will furnish copies of drawings, pictures, letters, and the like at reasonable cost and quickly.

Another object is to provide an electronic reproducer that will be automatic in operation; producing a given number of copies after being set properly.

A further object is the provision of an electronic reproducer which can be used to make copies of different originals, without breaking the vacuum. n

An additional object is to provide an electronic reproducer the photosensitive surface of which is protected from harmful atmospheric or other innuences when the Vacuum is broken.

Other objects will appear in the following description.

In the drawing:

Figure 1 is a side elevation, in part section, of my electronic reproducer, showing a lamp, the glass or other transparent container, driving motor, evacuating pump, and other associated parts,

Figure 2 is a fragmentary side elevation, in part section, of a variation of my electronic reproducer in which the photosensitive surface is covered before air is admitted to the container.

Figure 3 is a plan view of a driving motor with automatic cut-ofi to stop the motor after a predetermined number of copies are made.

Figure 4 is a fragmentary end View, in part section, of a selenium type of reproducer.

In Figure 1, container I is made of glass or other transparent material, although wall 2 only can be transparent if desired. This container has top 3 which may be pressed tightly against the upper edge of container I in air-tight manner, by means of cross plate 4 which is provided with suitable holes through which end-threaded rods 5 and 6 pass. Thumb nuts 1 and 8 may be screwed down on rods 5 and 6 to apply pressure 2 to plate 4 and consequently to top 3 to eiect a seal. A suitable gasket may be provided. The bottom ends of rods 5 and 6 are screwed into base 9 which may be of any suitable material.

Top 3 may be hinged or clamped to container I so that plate 4 and rods 5 and 6 may be eliminated. Any suitable clamp may be used but should preferably be quickly manipulated. In this case it would be preferable to have wall 2, or a part thereof, of glass and the rest of the container, including top 3, of metal. A suitable seal between the glass and metal would be provided.

The inner surface, or at least a portion of the inner surface of `wall 2, is covered with semitransparent photo-emissive surface I0 which 1s adapted to emit electrons in proportion to the intensity of light rays from electric lamp I I held at the focus of parabolic reilector I2 which is fastened to support I3 xed to base 9. Any suitable source of parallel light rays may be used however, or in Vsome cases even illumination through ground glass could be used.

Surface I may be made by depositing a thin layer of silver on the inner glass surface of wall 2. Then a thin layer of caesium or other photoemissive material may be deposited over the silver by evaporation or otherwise. The top surface of the silver may be oxidized before depositing the caesium, by glow discharge or in other mannel'.

The silver is electrically connected to conductor I4 which leads to the negative pole of battery or other potential source Iia, the positive pole of which is connected to nickel or other metal plate I5 by means of conductor I6. Plate I5 serves as the anode and is fastened to upright I'I by means of posts I8. Upright II may be of insulating material and is suitably fastened to base I9 which may be set upon or fastened to container base 20.

The photo-emissive surface IQ may consist of a variety of materials such as potassium hydride, silver, caesium-on-silver, or the like. It is preferable that this photo-emissive surface be of such material that it will not be materially damaged by exposure to the atmosphere. Since many metals eject electrons upon exposure to light, a variety of useful substances are available. The methods of making photo-emissive surfaces are well known and consequently will not be described in detail.

Upright I 'I and a similar slotted upright on the opposite side of base I9 support rod 2I which carries spool 22 around which electrically sensitive paper 23 is wound. This paper is fed over guide rollers 24 and 25 supported on arms 26 and 21 and similar arms attached to upright I1 at the opposite end of Spool 22. The paper may rub against anode plate I if desired, or may be slightly separated from it as shown. Paper 23 is wound upon bottom spool 28 which is rotated by shaft 29 having bearing in uprights I1. Gear 30 is fastened to the end of shaft 29 and is meshed with gear 3| which is driven by reduced speed motor 32 fastened to base I9.

Motor 32 is supplied electrical energy through conductor 33, sealed in container I, and through conductor 34, similarly sealed and leading to brush 35 pressing against metal slip ring 36 a short section 36a of which is made of porcelain, mica, or other insulating material. Brush 38 also presses against slip ring 36 and is connected to a pole of switch 39 the other pole of which connects to line wire 40. Energy is therefore supplied to motor 32 when Switch 39 is closed and when the metal portion of slip ring 36 bridges the brushes 35 and 33.

Slip ring 36 and smaller slip ring 4I are rotated at reduced speed by motor 42, by means of epicyclic or other suitable reduction gears Motor 42 drives evacuating pump 43 which removes air or other gas from container I through connected pipe 44, which is sealed in container I; when valve 45 is open. The air is exhausted through outlet pipe 46. This` pump may be of any suitable type and may include an auxiliary high vacuum mercury vapor or similar pump. The pump should have suiiicient capacity so that container I can be evacuated to the desired low pressure in a minimum of time, within several minutes or less preferably.

Motor 42 is supplied energy through conductors 41 and 48. a suitable switch being provided.

Brush 49, supported on the motor frame, is connected with Wire leading to lamp II. Brush 49 presses against slip ring 4I which is of insulating material such as mica, fibre, bakelite or the like, except for relatively short arcuate portion 5I which is made of metal. This conducting portion is placed radially in alignment with insulating portion 36a of slip ring 36, so that lamp II will be lighted when motor 32 is stationary. Brush 4B, supported on the motor frame, also presses against slip ring 4I and is connected to line wire 52. The other cooperating line wire 53 is connected to the other terminal of lamp II by means of wire 54 which may be passed through base 9.

Spring clips 55 and 56 are fastened to the outside of Wall 2 and serve to hold letter 51 or other object to be copied, flat against the surface. A glass plate may be placed over letter 51 to press it against wall 2, if desired.

Motors 32 and 42 may be synchronous motors or of any suitable type. The motor speeds or reduction gearing, or both, should be so chosen that paper 23 will be moved through the maximum frame length or effective image length, when slip rings 36 and 4I are rotated through one revolution.

While motor 32 is shown at bottom, it is preferable that spool 28 be placed at the top so that the exposed paper can be easily reached. The whole assembly could be slipped out if desired; flexible or sliding motor contacts being provided for that purpose.

Paper 23 may be of any suitable electrically Teledeltos. In fact, it is not essential that it be electrically sensitive since the electrons can be made to burn their images in the paper or other material.

In operation, a roll of the paper on spool 22 is placed in the device and the other end is attached to shaft 29 of spool 28. Then top 3 is placed in position and thumb nuts 1 and 8 are screwed down to press plate 4 against top 3 to effect an air-tight seal. Valve 45 is then opened and motor 42 is energized to evacuate container I quickly. When the desired degree of vacuum is reached, as indicated by a suitable gage or after a predetermined time interval, letter or drawing 51 is placed as shown and switch 39 is closed. When this happens motor 32 will move paper 23 through a frame length, then will stop for a brief period during which time lamp II will be lighted so that the light Will pass through letter 51 and will cause an electron pattern to be liberated from photo-emissive surface I0, the density of the electrons corresponding in inverse relation to the opacity of the letter 51. The electron image will be accelerated by positively charged anode I5 so that an image will be made on paper 23, by electron bombardment. This image can be made visible and permanent or the electrically charged condition of the paper can be used to affect the rate of taking up inl: if a printing art process is desired.

As the motors continue to revolve, a succession of copies Will be made. After the desired copies are made, letter or other object 51 can be changed if desired Without breaking the seal of container I.

In case letter 51 is not translucent, a reflected image can be projected on wall 2, by means oi a suitable lens system.

When the desired copies are obtained, switch 39 is opened and motor 42 is similarly stopped. Thumb nuts 1 and 8 are then screwed up so that top 3 can be lifted and the exposed paper bearing the images can be remo-ved.

It is obvious that paper 23 could be moved by solenoid action, with a cooperating ratchet. Many other variations can easily be made.

In fragmentary Figure 2, container 58 has top 59 and two sealed-in pipes 60 and 6I which may be connected to an exhaust pump and a source of Yinert gas such as argon, nitrogen, helium or the like, respectively.

Photo-emissive surface 62 on transparent plate 63 serves as the cathode to produce an electron image pattern which is accelerated toward anode 64. Inclined rubber or other rim 65 is provided around the periphery of plate 63 so that inclined plate 66 will seal off photo-emissive surface 62 from the atmosphere when plate 66 is pressed down against rim 65. Plate 66 is moved vertically by means of integral rack B1 and cooperating pinion 68 driven by motor 69 which may be suitably energized. When the container has been evacuated, plate 66 is raised to the position shown, before use. As a further precaution against damage to surface 62, inert gas may be admitted to the container through pipe 6I when top 59 is removed. This gas may be directed against surface 62. The letter to be copied may be placed against plate 63 inside, if desired.

In Figure 3, motor 10 may be used to drive the paper or the pump. Collar 12 is provided with ratchet or pin 13 which may be adjusted to allow the collar to be slipped laterally on threaded motor shaft 1I so that collar 12 may be set, by means of attached pointer 14 and cooperating scale 15 fastened to motor 10, to allow a predetermined number of copies to be made before collar 12 is moved by rotating shaft ll until it strikes and opens switch 'I6 which stops the motor.

In Figure 4, metal screening 'Il' is connected to one pole of battery-or other current source 18 the other pole of which is connected to metal plate 19. Thin selenium plate 80 is pressed against preferably moist electro-sensitive paperfl which is pressed against plate 79. If then a letter is pressed against screening 11 by means of a glass plate or otherwise, then the current conducted by the elemental areas of the selenium will be according to the opacity of the letter so that an image will be made on paper Bl. Light is, of course, directed through the letter.

-Many changes of detail-can, of course, be made without departing from the general principles I have disclosed. For instance, electrically energized magnets or solenoids can be used to force plateGS against rim 65 when it is desired to protect surface 62. The energization of the magnets can be made automatic when the top 59 is removed, or before. Likewise, the introduction of inert gas can be made automatic.

In the specificationk and claims, the word light denotes radiation of any suitable kind, whether of lvisible wavelengths or invisible such as infra-red, ultra-violet, X-ray, or other radiation.

What I claim is:

l. The method of making reproductions of typewriting, printed matter, drawings or the like, comprising, forming a light image of the object to be copied, transforming said image into an electron image, and directing said electron image against material adapted to be visibly changed in character or color byelectron bombardment.

2. The method of making reproductions of typewriting, printed matter, drawings or the like, comprising, forming a light image of the object to be copied, transforming said image into an electron image, and directing said electron image against material adapted to be chemically changed by electron bombardment visibly to reproduce said image in or on said material.

3. An electronic device comprising, a container having a, light transmitting wall, a closure for said container, a translucent coating of photoemissive material on at least a portion of the inner surface of said wall, an electrically conducting plate substantially parallel with said wall, electrical conductors connected with said coating and said plate, electrical means connected With said conductors for charging said plate positively with respect to said coating, a pair of rollers within said container, means to support said rollers, and electrical means operatively connected with at least one said roller to rotate said roller.

ll. An electronic device comprising, a container having a light transmitting wall, a closure for said container, a translucent coating of photoemissive material on at least a portion of the inner surface of said Wall, an electrically conducting plate substantially parallel with said wall, electrical conductors connected with said coating and said plate, electrical means connected with said conductors for charging said plate positively with respect to said coating, a pair of rollers within said container, means to support said rollers, electrical means operatively connected with at least one said roller to rotate said roller, and a sheet of material which may be visibly and permanently changed by electron bombardment adapted to be moved between said coating and said plate by means of said1 rollers.

5. An electronic device comprising, a container having a light transmitting wall, a closure for said container, .a translucent coating of photoemissive material on at least a portion of the inner surface of said wall, an electrically conducting plate substantially parallel with said wall, electrical conductors connected with said coating and said plate, electrical means connected with said conductors for charging said plate positively with respect to said coating, a pair of rollers within said container, means to support said rollers, and electrical means operatively connected with at least one said roller to rotate said roller in a succession of predetermined steps.

6. An electronic device comprising, a container having a light transmitting wall, a closure for said container, a translucent coating of photoemissive material on at least a portion of the inner surface of said wall, an electrically conducting plate substantially parallel with said wall, electrical conductors connected'with said coating and said plate, electrical means connected with said oonductors'fo-r charging said plate positively with respect to said coating, a pair of rollers within said container, means to support said rollers, electrical means operatively connected with at least one said roller to rotate said roller, and an evacuating pump connected with said container.

7. An-electronic device comprising, a container having a closure therefor, at least a portion of said container being of light-transmitting character, a film of photoemissive material within said container and positioned to receive light passing through said portion, an electrically conducting element adjacent said lm, electrical conductors connected with said film and said element, means electrically connected with said conductorsvfor establishing an electrostatic field between them, and pumping means connected with said container to cause evacuation thereof.

8. An electronic device comprising, a containel1 having a closure therefor, at least a portion of said container being of light-transmitting character, a m o-f photoemissive material within said container and positioned to receive light passing through said portion, an electrically conducting element adjacent said film, electrical conductors connected with said nlm and said element, means electrically connected with said conductors for establishing an electrostatic field between them, pumping means connected with said container to cause evacuation thereof, a sheet of material of a character to be visibly and permanently changed by particle bombardment positioned between said lm and said element, and means within said container for moving said sheet.

9. An electronic device comprising, a container having a closure therefor, at least a portion of said container being of light-transmitting character, a film of photoemissive material within said container and positioned to receive light passing through said portion, an electrically conduct-r ing element adjacent said film, electrical conductors connected with said film and said element, means electrically connected with said conductors for establishing an electrostatic field between themVpumping means connected with said container to cause evacuation thereof, a sheet of material of a character to be visibly changed by particle bombardment positioned between said nlm and said element, and means for moving said sheet through predetermined displacements.

l0. An electronic device comprising, a container having a closure therefor, atleast a portion ofv said container being of light-transmitting.

character, a film of photoemissive material within said container and positioned to receive light pass ing through said portion, an electrically conducting element adjacent said film, electrical conductors connected with said film and said element, means electrically connected with said conductors for establishing an electrostatic field between them, pumping means connected with said container to cause evacuation thereof, a sheet of material of a character to be visibly changed by particle bombardment positioned between said film and said element, and means including a motor within said container for moving said sheet.

11. An electronic device comprising, a container having a closure therefor, at least a portion of said container being of light-transmitting character, a film of photoemissive material within said container and positioned to receive light passing through said portion, an electrically conducting element adjacent said film, electrical conductors connected with said film and said element, means electrically connected with said conductors for establishing an electrostatic field between them. pumping means connected with said container to cause evacuation thereof, and illuminating means fastened to said device to direct light through said portion and said film.

12. An electronic device comprising, a container having a closure therefor, at least a portion of said container being of light-transmitting character, a film of photoemissive material within said container and positioned to receive light passing through said portion, an electrically conducting element adjacent said film, electrical conductors connected with said film and said element, means electrically connected with said conductors for establishing an electrostatic field between them, pumping means connected with said container to cause evacuation thereof, illuminatingr means fastened to said device to direct light through said portion and said film, and automatic means connected with said illuminating means to cause illumination of said film for predetermined intervals.

13. An electronic device comprising a container having a closure therefor, at least a portion of said container being of light-transmitting character, a film of photoemissive material within said container and positioned to receive light passing through said portion, an electrically conducting element adjacent said film, electrical conductors connected with said film and said element, means electrically connected with said conductors for establishing an electrostatic field between them, pumping means connected with said container to cause evacuation thereof, a sheet of material of a character to be visibly changed by particle bombardment positioned between said film and said element, and automatic means for moving said sheet through a succession of predetermined displacements with predetermined stationari7 intervals between said displacements.

14. An electronic device comprising a container having a closure therefor, at least a portion of said container being of light-transmitting character, a film of photoemissive material within said container and positioned to receive light passing through said portion, an electrically conducting element adjacent said film, electrical conductors connected with said film and said element, means electrically connected with said conductors for establishing an electrostatic field between them, pumping means connected with said container to cause evacuation thereof, illuminating means associated with said device to direct light through said portion and said film, a sheet of material of a character to be visibly changed by particle bombardment positioned between said film and said element, automatic means for moving said sheet through a succession of predetermined displacements, and automatic means to affect said illuminating means to direct light through said film during stationary intervals of said sheet between intervals of said displacements.

15. An electronic device comprising a container having a closure therefor, at least a portion of said container being of light-transmitting character, a film of photoemissive material within said container and positioned to receive light passing through said portion, an electrically conducting element adjacent said film, electrical conductors connected with said film and said element, means electrically connected with said conductors for establishing an electrostatic field between them, pumping means connected with said container to cause evacuation thereof, and automatic means to time the emission of electrons from said film.

16. An electronic device comprising a container having a closure therefor, at least a portion of said container being of light-transmitting character, a film of photoemissive material within said container and positioned to receive light passing through said portion, an electrically conducting element adjacent said film, electrical conductors connected with said film and said element, means electrically connected with said conductors for establishing an electrostatic field between them, pumping means connected with said container to cause evacuation thereof, and means within said container to cover said film to prevent exposure to air when said closure is opened.

17. An electronic device comprising a container having a closure therefor, at least a portion of said container being of light-transmitting character, a film of photoemissive material within said container and positioned to receive light passing through said portion, an electrically conducting element adjacent said film, electrical conductors connected with said film and said l element, means electrically connected with said conductors for establishing an electrostatic field between them, pumping means connected with said container to cause evacuation thereof, an element within said container to cover said film to prevent exposure to air when said closure is opened, and electrical means to actuate said element.

18. An electronic device comprising a container having a closure therefor, at least a portion of said container being of light-transmitting character, a nlm of photoemissive material within said container and positioned to receive light passing through said portion, an electrically conducting element adjacent said film, electrical conductors connected with said film and said element, means electrically connected with said conductors for establishing an electrostatic field between them, pumping means connected with said container to cause evacuation thereof, and means connected with said container for introducing gas therein to protect said film when said closure is opened.

19. The method of making reproductions, said method comprising the steps of directing light against an object to be copied to produce a lightand-shadow image thereof, allowing said image to strike a photoemissive surface to cause emission of an electron pattern in accordance with said image, and accelerating said electron pattern against material of a character to be visibly 9 and permanently changed by said electron pattern in accordance therewith..

20. The method oi protecting a photoemissive surface of an electronic device having a container adapted to be opened to atmosphere, said method comprising sealing 01T said surface from the atmosphere While said container is open.

10 21. The method of protecting a phctoemissive surface of an electronic device having a container adapted to be opened to atmosphere, said method comprising surrounding said surface with protesting gas While said container is open.

ALBERT G. THOMAS.

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