US2185239A - Cathode ray tube - Google Patents

Cathode ray tube Download PDF

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Publication number
US2185239A
US2185239A US137159A US13715937A US2185239A US 2185239 A US2185239 A US 2185239A US 137159 A US137159 A US 137159A US 13715937 A US13715937 A US 13715937A US 2185239 A US2185239 A US 2185239A
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United States
Prior art keywords
electrode
cathode
deflecting
cathode ray
electron
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
Application number
US137159A
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English (en)
Inventor
Ardenne Manfred Von
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RCA Corp
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RCA Corp
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Filing date
Publication date
Priority to US727206A priority Critical patent/US2080449A/en
Priority claimed from US727206A external-priority patent/US2080449A/en
Priority to FR774334D priority patent/FR774334A/fr
Priority to GB17249/34A priority patent/GB419872A/en
Application filed by RCA Corp filed Critical RCA Corp
Priority to US137159A priority patent/US2185239A/en
Application granted granted Critical
Publication of US2185239A publication Critical patent/US2185239A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J29/00—Details of cathode-ray tubes or of electron-beam tubes of the types covered by group H01J31/00
    • H01J29/46—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement

Definitions

  • My invention relates to improvements in and methods of operation of cathode ray tubes, in particular for use as oscillographs and in cathode ray television systems.
  • the general form of cathode ray tubes heretofore known in the art used for oscillographs or in cathode ray television comprises the three essential parts: a thin beam or pencil of electrons, a fluorescent target or luminous screen for the electron pencil to strike against to produce a recording light spot, and a mechanism for deflecting the electron beam and varying the intensity of the luminous spot on the screen for producing an image or pattern of desired configuration and charac- .teristics.
  • the sensitivity of deflection of an electron ray may be increased if the deflection takes place at a place Where the electrons travel at low speed.
  • the electron beam is initially accelerated to a fraction only of the desired final speed and is then passed through the deflecting system whereupon a final acceleration is applied to secure sufficient kinetic energy of the electron beam striking the fluorescent surface to produce a bright luminous spot thereon.
  • the electron speed in the ray-producing and reflecting space had to be of comparatively high value (several hundred volts) in order to secure a sufficient current intensity at the top of the ray or in turn a. sufficiently brilliant luminous spot on the fluorescent screen.
  • a further object of my invention consists in-a novel method and means whereby an extremely low electron speed may be employed within the space of the deflecting system, resulting in a considerably increased sensitivity of reflection while maintaining simultaneously high velocity of the electron ray at the place where the ray strikes against the fluorescent screen.
  • Still a further object of my invention is the provision of a novel electrode construction in a cathode ray tube for deflecting the beam at a place immediately near the cathode where the electrons move with the lowest velocity, resulting in greatly increased sensitivity of the deflec-
  • One of the diificulties experienced with cathode ray tubes as known heretofore in the art is the fact that a substantial reaction, especially capacitative reaction, may take place between the deflecting systems used for deflecting the beam in both a vertical and horizontal direction, in particular if two pairs of capacitative deflecting plates are used. This deflection may result in substantial decrease of the sensitivity of deflection, in distortion, and otherwise greatly interfere with the proper operation of the tube.
  • Figure 1 schematically illustrates a cathode ray tube having an electrodeacccrding to Figure 2 embodied therein;
  • Figure 2 illustrates an electrode construction for accelerating or decelerating an electron beam in accordance with my invention
  • Figure 3 illustrates another form of cathode ray tube embodying an electrode system enabling the deflection of the cathode ray immediately near the cathode, resulting in greatly increased sensitivity of the reflection;
  • Figure 4 illustrates a bottom View of the tube according to Figure 3 and the connections to the deflecting plates from a controlling source;
  • Figure 5 is a front view of the anode or shielding electrode provided in the tube shown by Figure 3;
  • FIGS 6, 6a and '7, 7a schematically illustrate electrode systemsvfor cathode ray tubes employing the shielding element in accordance with my invention.
  • I provide a means in a cathode ray tube for accelerating an electron ray from either an initial very low velocity or a reduced velocity obtained by previous deceleration to a desired final acceleration without otherwise impairing the operating characteristics and sensitivity of deflection of the electron ray.
  • an accelerating electrode insuring a gradual potential variation from the place of the initial or starting potential to the final potential to which the ray is to be accelerated.
  • I use a tubular shaped unit'as an accelerating electrode comprising substantially two cylindrical elements provided with wedge-shaped teeth engaging each other whereby the acceleratingpotentialis applied to one of said elements.
  • FIG. 2 This construction illustrates the cylindrical metallic unit, or unit provided with a metal coating, used as an accelerating means in which the cylinder is shown to be cut open lengthwise and spread out into a plane.
  • I have shown the one element at M provided with wedgeshaped teeth i l and the second cylindrical element at l2 provided with similar wedge-shaped teeth l2 engaging the teeth of the first element as shown.
  • the embodiment as shown by Figure 2 is of a specific and preferred form to be used for both final acceleration and previous deceleration of the electron beam, and for this purpose I have shown further wedge-shaped teeth l4. connected to the other side of the cylindrical element Mand a'further cylindrical element 11 5 provided with teeth It engaging teeth M of the element Hi. The arrangement and function of this construction will be explained further in connection with Figure 1.
  • the conditions obtained are such that a highly homogeneous electric field consists for both undeflected and largely deflected rays passing inside the cylindrical unit.
  • the electrode structure for accelerating or decelerating an electron beam in accordance with the invention is of such configuration and design as to produce an accelerating or decelerating electric field which exerts a substantially equal force upon the electrons independent of the direction of the beam through the field.
  • both the deflected and undeflected beam is accelerated or decelerated in an equal manner without in any way affecting the characteristics of the beam, such as its initial velocity, degree of concentration, etc. liable to produce distortion of the pattern or image produced by the beam upon the luminescent screen.
  • I overcome this defect by using a higher initial acceleration voltages in the ray producing sys tem equal to, about one-half to one-eighth of the desired electron Velocity at the luminous screen.
  • I then provide means for decelerating the electrons within the deflecting space and in this manner I have found it possible to secure extremely high degrees of sensitivity of deflection especially in gas filled cathode ray tubes.
  • The'deceleration may be carried out to substantially lower electron volt velocities as would be possible in the above mentioned case where low initial velocity is employed in the space where the ray is produced and initially concentrated, such as by means of a negatively biased concentration cylinder.
  • the deceleration may be carried out by means of ordinary electrodes, such as by the provision of a pair of circular plates with central openings for passing the electron ray whereby the braking or decelerating voltage is applied to the second electrode.
  • ordinary electrodes such as by the provision of a pair of circular plates with central openings for passing the electron ray whereby the braking or decelerating voltage is applied to the second electrode.
  • I prevent the aforementioned deviation of the beam by the decelerating field by the prcvision of a similar shaped cylindrical electrode system with mutually engaging wedge-shaped teeth as hereinbefore described for efiecting a final or re-acceleration of the electron beam to the desired final velocity.
  • FIG. 1 of the drawing I have shown a cathode ray tube embodying an electrode system as described by Figure 2 used for both decelerating and subsequently accelerating an electron beam for the purpose as described.
  • a cathode ray tube comprising a glass bulb l having a neck shaped portion housing the electrode systems for producing and deflecting the electron ray and a spherical shaped end portion including an inclined luminous screen it as described in my ccpending application entitled Improvements in and methods of operatingcathode ray tubes of even date.
  • Numeral 2
  • cathode which maybe a thermionic filamentary cathode as shown, but it is understood'that any other type of cathode may be provided, such as an indirectly heated cathode of known design in the art.
  • the cathode is shown to be heated by a battery 1 and is surrounded by a cylindrical or concentration electrode 3 negatively biased to the cathode by means of a biasing battery as shown at 8 for concentrating the electron stream into a sharply focused pencil.
  • a positive or anode electrode for producing an initial acceleration of the electron beam emanating from the cathode and the concentration cylinder 3.
  • the electrode I5 may be of ring-shape with a central opening and provided with a cylindrical unit having wedge-shaped teeth #5 similar to the unit i5 as described by Figure 2.
  • the electrode I 5 is connected to a high positive operating potential of about 1000 volts such as shown by the battery 9 to initially accelerate the electron beam.
  • Numeral I represents a breaking or deceleration electrode having a lower positive potential applied to it than the electrode 55, such as by means of battery I! as shown.
  • the electrode i0 may also be of circular shape with a central opening for passing the electron ray and connected to the cylindrical unit M with teeth It engaging the teeth iii of element l as shown in more detail in Figure 2.
  • the thus deflected electron ray is subsequently reac-celerated to its final velocity by means of the tubular accelerating electrode i2 provided with wedge-shaped teeth l2 engaging the teeth Id of the electrode M.
  • a i e-acceleration of the electron beam even when deflected to its fullest degree in both coordinates is insured without any substantial impair ment of its characteristics.
  • the accelerating potential which may be of the same value as the breaking potential (1000 volts in the above example) applied by a battery !3 connected to the element it. It was furthermore found that the conditions and the operation can be improved by biasing the screen It to a potential equal to the accelerating potential such as shown by the connection of the screen to the plus pole of the battery I3. In the example as illustrated the potential of the battery i may be within the order of 100 volts or less.
  • the electrode NJ it is advisable to provide the electrode NJ with a very small aperture through which the low speed electrons pass, especially in the case of very high deceleration to very low electron velocities.
  • cathode ray tube construction for deflecting the electron beam immediately at the source or cathode where the electron speed is a minimum, thus obtaining a maximum sensitivity of the deflection, as is obvious.
  • This type. of construction is especially suited for partly or highly evacuated tubes in which the electron velocity at the cathode may be of a very low value as compared with gas filled tubes hereinabove mentioned.
  • FIG. 3 I have again shown a cathode ray tube comprising a glass bulb I mounted upon a base I1 and provided with an inwardly projecting press [8 for carrying the cathode, anode and the deflecting system.
  • the cathode ray tube shown in this figure differs from Figure 2 by the arrangement of the luminous screen I9 directly applied to the inner end wall of the tube in accordance with well known constructions in the art.
  • Numeral 20 represents the cathode similar as described by Figure 2 connected to terminals 20' mounted at the sides of the base 11.
  • I have furthermore shown a boxlike system comprising four plates 2!, 22, 23 and 24 arranged in square shape close to each other and surrounding the cathode.
  • Each of the plates is connected to a connecting terminal or prong 2
  • Figure 4 also shows a cross-section of the plate system and the connection to the prong terminals.
  • the electron beam can be deflected in one direction by applying the controlling potential supplied from a transformer or other source is shown in Figure 4 to a pair of opposite plates, in the example illustrated plates 23 and M.
  • and 22 should be connected to the mid-tap point of the controlling source l8, in the example the secondary of the transformer winding as illustrated.
  • the latter provided with a. lengthwise slit 25" to allow the beam to sweep over the entire surface of the luminous screen in a horizontal direction according to the specific example as shown in more detail by Figure 5. If it is further desired to sweep the beam in a vertical direction, a pair of ordinary deflecting plates as shown at 255 may be arranged behind the anode 25.
  • the anode 25 furthermore acts as a screen between the two defleeting systems for preventing decrease of sensitivity of the deflection and distortion caused by electrostatic interaction between the deflecting systems.
  • a shielding electrode as shown at 25 in Figure 3 may be employed in connection with any other electrode system in cathode ray tubes and is not limited to the particular construction according to Figure 3 in which the shielding electrode simultaneously acts as an anode for the electron stream.
  • FIG. 6 shows schematically an electrode system of usual construction in combination with a shielding electrode according to the invention.
  • Numeral 28 indicates the cathode ray source such as the concentration cylinder surrounding a cathode.
  • Numeral 29 represents the usual anode which may be in the form of a disc with a central opening for passing the cathode ray.
  • Numeral 3B shows a first pair of deflecting plates to sweep the beam in a vertical direction.
  • FIG. 1 represents a shielding electrode in accordance with the invention comprising a disc provided with a vertical slit to allow the beam to sweep vertically between the upper and lower deflecting positions, and numeral 32 indicates a second pair of deflecting plates for sweeping the beam in a horizontal direction.
  • FIGS and 7a illustrate a similar system with the succession of the deflection reversed, in which case the shielding electrode 3! is arranged with its slit in a horizontal position, as will be understood.
  • a cathode ray tube comprising a means for producing a concentrated electron beam, a luminescent screen for said beam to strike against, a first deflecting system for sweeping beam over said screen in one direction, a further deflecting system for sweeping said beam in different direction, a screening member arranged between said deflecting systems provided with a lengthwise slit for allowing passage of said beam while being swept over the entire surface of screen by said first deflecting n'zeniiher, and electrode means for accelerating the said beam following the two deflecting systems.
  • a cathode ray tube comprising means for producing a concentrated electron bearn, a luminescent screen for said beam to strike against, a first deflecting system comprising a pair of electrostatic deflecting plates for sweeping said beam over said screen in one direction, a second deflecting system comprising a pair of electrostatic deflecting plates for sweeping said beam over said screen in a direction at right angle to said first direction, a metallic screen separating said deflecting systems and provided with a slit to allow passage of said beam while being swept over the entire surface of said screen by said first deflecting system, and electrode means for accelerating the said beam following the two deflecting systems.
  • a cathode ray tube comprising a cathode, a first cylindrical electrode surrounding the cathode, a second cylindrical electrode coaxial with and spaced from the first cylindrical electrode, a third cylindrical electrode coaxial with and spaced from the second cylindrical electrode, a fourth cylindrical electrode intermediate the second and third cylindrical electrode said second, third and fourth electrodes being serrated and interleaved at their adjacent boundaries, cathode ray deflecting means positioned within the fourth electrode, and a luminescent screen positioned in register with and spaced from the third cylindrical electrode.
  • a cathode ray tube comprising a cathode, a cylindrical electrode surrounding the cathode, a second cylindrical electrode coaxial with and spaced from the first cylindrical electrode, a third cylindrical electrode coaxial with and spaced from the second cylindrical electrode, a fourth cylindrical electrode intermediate the second and third cylindrical electrodes, an apertured electrode Within the fourth cylindrical electrode, said electrode having an elongated aperture to permit a beam of electrons to pass without hindrance, while said beam is deflected over substantially the entire width of the luminescent screen, cathode ray deflecting means positioned within the fourth cylindrical electrode, and a luminescent screen positioned in register with and spaced from the third cylindrical electrode.
  • a cathode ray tube comprising a cathode, a cylindrical electrode concentric with the oathode, a first cylindrical saw-tooth electrode coaxial with and spaced from the cathode, a second cylindrical saw-tooth electrode spaced from the first saw-tooth electrode, an apertured disk electrode intermediate and in register with the first and second saw-tooth electrodes, a third cylindrical sawtooth electrode intermediate the first and second saw-tooth electrodes and surrounding the disk electrode, cathode ray deflecting means intermediate the first and second saw-tooth electrodes, and a luminescent screen in register with and spaced from the second saw-tooth electrode.
  • a cathode ray tube comprising a cathode, a cylindrical electrode concentric with the cathode, a first cylindrical saw-tooth electrode coaxial with and spaced from the cathode, a second cylindrical saw-tooth electrode spaced from the first sawtooth electrode, an apertured disk electrode intermediate and in register with the first and second saw-tooth electrodes, a third cylindrical sawtooth electrode intermediate the first and second saw-tooth electrodes and surrounding the disk electrode, two pairs of parallel plane electrodes mutually perpendicular to each other intermediate the first and second saw-tooth electrodes, and a luminescent screen in register with and spaced from the second saw-tooth electrode.

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  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Discharge Lamps And Accessories Thereof (AREA)
  • Radiation-Therapy Devices (AREA)
US137159A 1933-06-12 1937-04-16 Cathode ray tube Expired - Lifetime US2185239A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US727206A US2080449A (en) 1933-06-12 1934-05-24 Cathode ray tube
FR774334D FR774334A (fr) 1933-06-12 1934-06-08 Tubes de braun à pouvoir déviateur élevé
GB17249/34A GB419872A (en) 1933-06-12 1934-06-11 Improvements in or relating to cathode ray tubes
US137159A US2185239A (en) 1933-06-12 1937-04-16 Cathode ray tube

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE419872X 1933-06-12
US727206A US2080449A (en) 1933-06-12 1934-05-24 Cathode ray tube
US137159A US2185239A (en) 1933-06-12 1937-04-16 Cathode ray tube

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US2185239A true US2185239A (en) 1940-01-02

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US (1) US2185239A (fr)
FR (1) FR774334A (fr)
GB (1) GB419872A (fr)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2459637A (en) * 1944-11-29 1949-01-18 Motorola Inc Cathode-ray image-translating device
US2617077A (en) * 1950-08-11 1952-11-04 Motorola Inc Electrostatic deflection system for cathode-ray tubes
US2617076A (en) * 1948-01-13 1952-11-04 Motorola Inc Electrostatic deflection system
US2681426A (en) * 1952-03-06 1954-06-15 Motorola Inc Deflection system
US2766398A (en) * 1953-04-03 1956-10-09 Itt Electron discharge device
US2817044A (en) * 1949-06-23 1957-12-17 Siemens Ag Unsymmetrical electrostatic deflection device for electron radiation tubes
US2821648A (en) * 1953-04-15 1958-01-28 George W Baker Ion deflection thyratron
US2830228A (en) * 1955-05-05 1958-04-08 Motorola Inc Deflection system
US2897397A (en) * 1955-04-21 1959-07-28 Sylvania Electric Prod Traveling wave tube
US2951961A (en) * 1959-05-28 1960-09-06 Bell Telephone Labor Inc Electron beam deflection system
US3142779A (en) * 1957-12-12 1964-07-28 Csf Electrostatic deflection arrangement for electron tubes
US4695775A (en) * 1986-05-15 1987-09-22 Rca Corporation Imaging system having an improved electrostatic yoke and method of making same

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE757913C (de) * 1939-03-17 1953-06-01 Aeg Braunsche Roehre mit Ablenkplatten
JPS60198041A (ja) * 1984-02-20 1985-10-07 Sony Corp 陰極線管

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2459637A (en) * 1944-11-29 1949-01-18 Motorola Inc Cathode-ray image-translating device
US2617076A (en) * 1948-01-13 1952-11-04 Motorola Inc Electrostatic deflection system
US2817044A (en) * 1949-06-23 1957-12-17 Siemens Ag Unsymmetrical electrostatic deflection device for electron radiation tubes
US2617077A (en) * 1950-08-11 1952-11-04 Motorola Inc Electrostatic deflection system for cathode-ray tubes
US2681426A (en) * 1952-03-06 1954-06-15 Motorola Inc Deflection system
US2766398A (en) * 1953-04-03 1956-10-09 Itt Electron discharge device
US2821648A (en) * 1953-04-15 1958-01-28 George W Baker Ion deflection thyratron
US2897397A (en) * 1955-04-21 1959-07-28 Sylvania Electric Prod Traveling wave tube
US2830228A (en) * 1955-05-05 1958-04-08 Motorola Inc Deflection system
US3142779A (en) * 1957-12-12 1964-07-28 Csf Electrostatic deflection arrangement for electron tubes
US2951961A (en) * 1959-05-28 1960-09-06 Bell Telephone Labor Inc Electron beam deflection system
US4695775A (en) * 1986-05-15 1987-09-22 Rca Corporation Imaging system having an improved electrostatic yoke and method of making same

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Publication number Publication date
GB419872A (en) 1934-11-20
FR774334A (fr) 1934-12-05

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