Classifications

• • 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
  • H01J29/465—Arrangements of electrodes and associated parts for generating or controlling the ray or beam, e.g. electron-optical arrangement for simultaneous focalisation and deflection of ray or beam
• • 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
  • H01J29/70—Arrangements for deflecting ray or beam
  • H01J29/72—Arrangements for deflecting ray or beam along one straight line or along two perpendicular straight lines
  • H01J29/74—Deflecting by electric fields only
• • 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
  • H01J29/70—Arrangements for deflecting ray or beam
  • H01J29/72—Arrangements for deflecting ray or beam along one straight line or along two perpendicular straight lines
  • H01J29/76—Deflecting by magnetic fields only
• • 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
  • H01J29/80—Arrangements for controlling the ray or beam after passing the main deflection system, e.g. for post-acceleration or post-concentration, for colour switching

Definitions

• Fig. 16 is a tl'ostatic deflector systems of cathode-ray oscildiagrammatic representation showing the manlographs and television tubes. Its object is to her of connection and energization of the deprovide a new deflector system, with high deflecting electrodes.
• .y'flection sensitivity which is suitable for much In Fig. 1, which is a longitudinal section of a Wider deflection angles than hitherto used, and particularly simple design of a deflector system allows constructing very short cathode-ray tubes according to the invention, 1, 2, 3 and d are dewith large screens.
• flector plates Which are connected crosswise, i. e.,
• One feature of the invention comprises an im l is connected with 4 and 2 with 3.
• the two sysv 7 proved deflector system which includes two sets terns 2 and3-4 will therefore deflect the elecof successively arranged deflecting electrodes, trons in opposite directions.
• Systems of crosssuch electrodes being so energized as to produce wise connected deflector plates have been already opposite oscillatory deflections of the electron used in cathode-ray oscillographs in so-called stream.
• conbeam traps i.
• syst is s rr d as t produce a ssv case of the length of the second systemis used of the ys of the electron b at a point Withfor compensating the deflection angle produced in the deflecting structure.
• th first system Inthe remaining astrongof this feature, an electrostatic lens follows the r deflection i the opposite direction is produced.
• Fig. 1 is a Sketch of the new very large deflecting angles are produced.
• Fig. 13 5 is a diagram explaining the refraction of elec- E de5c11bef1 c a$e1 m whlch 32/ $1 is 3, glVeS tron rays in Fig 1 Fig" 1 1 an improved maximum sensitivity. If 1:2 is chosen larger, the
• each of the successively arranged two deflecting systems is shaped as a split ,tube. This is shown in Figs. 2 and 3 which are side and end views respectively of such a system.
• the cylinder segments 5 through 8 form the first, and 9, it!
• Fig. 4 shows a complete electron gun and deflector system of the last described kind.
• E2 is the cathode, It the modulating grid
• the mean potential of the deflector systems is equal to the final driving voltage .of the tube. Therefore 5 between it and El, an electron lens formed,
• the deflecting sensitivity of this system can be even further increased by the method known per se of deflecting the electrons before they have obtained their final velocity. As shown in Fig. 5, this can be effected in a particularly simple Way, by omitting the second anode l 6 in Fig. 4 and using the deflector systems themselves as second anode.
• the final lens can be obtained by joining a further ring to the system or, as shown in Fig. 5, by using the conducting coating of the tube itself as final anode.
• I9 is the cathode, 28 the grid, M the first anode, 22 the first deflecting system, 23 the second deflecting system, and 24- the conducting coating on the tube envelope. It is of course understood that the electron gun and the lenses as shown in this and the following examples are chosen also by way of illustration and can be replaced by any other known guns or lenses.
• Fig. 6 is a diagram, by means of which the resulting deflecting sensitivity can be obtained.
• This diagram shows the cardinal points of the electron lens corresponding to the actual dimen sions of Fig. 5, in the case where the mean potential of the deflecting system is A of the final voltage, i. e., if the total driving voltage is 4000' volts and the mean potential of the deflecting plates F1 is the first, F2 the second focusis 1000 volts. of the electron lens so formed, H1 and H2 are its It is seen that in spite of the two principal planes.
• Every lens has two nodal points of the following properties: A ray passing from the'object space through the first nodal point N1 after having passed through the lens. will appear coming from the second nodal point Nzf in a direction parallel to the original ray.
• These nodal points can be constructed as shown in Fig. 6.
• the distance of N1 from F2 is equal to ii, the first focal length, and the distance of N2 from F1 is equal to the second focal length f2. It is seen that in Fig. 5 the nodal point N1 is at far too great a distance from the pivot point P.
• the new deflector system can be operated with suitable combinations of lenses in such a way as to eliminate the astigmatism which up to now has been a major disturbing factor in cathode-ray tubes, especially in tubes for television purposes.
• Fig. explains-the phenomenon of deflection astigmatism.
• 2S and 30 are the two plates of a deflecting condenser.
• a and b are two electron trajectories, which are parallel if no deflecting field is acting. If, however, a field is produced, the deflected rays will cross over, as the ray a nearer the negative plate 25- will suffer stronger deflection than the ray 1).
• Act is the diiference between the angles by which two rays have been deflected, which have passed through a deflecting field, at a distance AN from each other; the distance varying in general along the path S. ⁇ ,l/ is the potential, measured against the cathode. tip/ and tap/5N are the first and the second partial derivatives with respect to the direction 11, perpendiculan to the trajectory. Ifas in most CELSESA:1 is small compared with a, we can calculate this integral with sufiicient accuracy assuming that AN has varied in the same way along the path s as if no deflection had taken place. In the case shown in Fig. we could e.
• I eliminate astigmatism by providing inside the deflecting system a crossing point of the electron rays, i. e., an
• Fig. 11 shows a parallel condenser system, in which an image is i produced at the center C. According to equation 2 this system is anastigmatic. W e can not utilize it, however, for the following reason: If we want to obtain eventually an image or C on the screen, a lens must be placed behind the deflecting systern. As, however, the screen. is at a large distance, this means that C must nearly coincide with the first focal point of the lens. As now the pivot point in this deflecting system is also C, this means that the deflection will be nearly 3 completely destroyed by the lens.
• Fig. 12 is the cathode, 32 the grid, 33 the first 5 anode and 34 the second anode.
• 35 and 36 are the two deflecting systems, consisting of split cylinders.
• the anastigmatic center C is in this case again near the center of the whole deflecting system, whereas the pivot point P is at its end, inside the final lens, which is formed between 36 and the final anode 37. It is therefore possible to focus C on the screen without destroying the .deflections.
• the intermediate image C is produced in this example simply by the lens formed between 3 3 and 35, if the mean potential of 35 is different from the potential of. 3 1. It can be higher or lower; in any case the lens will be a concentrating lens.
• Fig. 13 shows that the deflection is not destroyed but even increased. This arrangement. This diagram corresponds to the case when the voltage of 3'! is seven times the mean potential of the deflecting systems. This potential ratio is necessary for focusing C on the screen at a distance of about 30 cms.
• Fig. 14 shows a combination of the same electron gun system as in Fig. 12 with the new deflection system as shown in Fig. 9.
• this system it is possible to fulfill both conditions which according to the invention make the deflection sensitivity large and the astigmatism zero, namely: The focal point of the final lens nearly coinciding with the anastigmatic center of the deflecting system, and the pivot point of. the deflecting system nearly coinciding with the first nodal point of the lens.
• Fig. 16 the cross-connection system referred to in connection with Figs. 1 to 4 is shown in detail.
• electrode 5 is connected to electrode H] by means of a conductor 40, electrode 5 to electrode 9 by means of a conductor 4
• a common source 45 of alternating scanning potential is connected across the conductors 5D and ll.
• the potential applied to the electrode pair 5, B is identical in periodicity but opposite in direction of deflecting action to that applied to the electrode pair 9, l0. Consequently, these pairs produce opposite oscillatory deflections of the electron beam traversing them.
• Similar functioning of the electrode pairs 1, 8 and II, l2 may be obtained by applying to them a second scanning potential from an appropriate source (not shown).
• an electron gun for projecting an electron beam along a given axis, a screen to be scanned by the beam and a deflecting system efiective to cause t beam to scan the screen, the said system including a frst electrode structure operative to produce initial cscil latory deflection of the beam.
• the second electrode structure arranged sequentially to the first for producing additional oscillator defiection of the beam in a direction opposite to as said initial deflection, the resulting pivoting point of the beam being adjacent the end of the said second electrode structure which is nearest to the screen, and an apertured electrode positioned between the said second electrode structure and the screen forming therewith an electron-optical lens, the second electrode structure being tapered the screen end and the apertured electrode being shaped to conform to the said taper, whereby the nodal point of the said electron lens is caused to coincide at least approximately with the said pivoting point of the electron beam.
• an electron gun for projecting an electron beam along given axis, a screen to be scanned by the beam and a deflecting system effective to cause the beam to scan the screen, the said system including a first electrode structure operating to produce initial oscillatory deflection of the beam and a second electrode structure arranged sequentially to the first for producing additional oscillatory deflection of the beam in a direction opposite to the said initial deflection, the beam being thus given an effective pivoting point relatively near to the l screen end of the said second electrode structure,
• means including an electron-optical lens adjacent the gun end of the electrode structure for producing a cross-over point within the said second deflecting electrode structure at a point different from the said pivotal point and a second electron-optical lens adjacent the screen end of the deflecting structure, the said lens having its focal point substantially coincident with the said cross-over point.
• a cathode ray tube comprising means including a cathode for producing a beam of electrons, a screen to be scanned by the said beam, beam deflecting structures arranged at two spaced positions along the axis of the tube, said structures including a pair of oppositely.
• each of the electrodes at one position being connected respectively to its oppositely disposed electrode at the other position whereby the beam is deflected in opposite directions in passing successively through said structures, means including an electron-optical lens adjacent the cathode end of the first deflecting structure for producing a crossover point Within the said second deflecting structure and a second electron-optical lens adjacent the screen end of the second deflecting structure, the said second lens having its focal point substantially coincident with the said cross-over point whereby anastigmatic deflection of the beam is obtained.
• a cathode ray tube comprising means ineluding a cathode for producing a beam of electrons, a screen to be scanned by the beam, two beam deflecting structures arranged sequentially along the axis of the tube, each structure including two pair of mutually perpendicular electrodes arranged in substantially closed configuration and each of the electrodes of the first structure being connected to an oppositely disposed electrode of the second structure, whereby the beam is deflected about a pivoting point relatively close to the screen end of the second structure, means including an electron-optical lens adjacent the cathode end of the first beam deflecting structure for producing a cross-over point within the second deflecting structure and means including a tapered portion at the screen end of the second deflecting structure and a conical electrode conforming with the said tapered portion for providing an electron-optical lens having its focal point substantially coincident with the said crossover point, whereby the deflection of the beam is rendered anastigmatic.
• a cathode ray tube comprising means for producing a cathode ray beam, a screen to be scanned by the beam and a deflecting system effective to cause the beam to scan the screen, the said system including a first electrode structure operative to produce initial oscillatory deflection of the beam and a second electrode structure arranged sequentially to the first for producing additional oscillatory deflection of the beam in a direction opposite to the said initial deflection, the resulting pivoting point of the beam being adjacent the end of the said second electrode structure which is nearer to the screen, and an apertured electrode arranged in. partially telescoping relation with the said end of the second electrode structure, the two last-named parts being of such configuration as conjointly to provide an electron lens having a nodal point approximately coincident with the said pivoting point of the beam.
• deflecting means including two mutually perpendicular electrode systems operable to cause the beam to scan the entire surface of the screen in successive increments, each of said electrode systems including a first pair of electrodes efiective when subjected to a potential difference to exert a deflecting force on the beam in a given plane parallel to the beam axis, a second pair of electrodes arranged sequentially to the first and in substantial alignment therewith, said second set of electrodes being dimensioned to act on the beam for a substantially greater portion of its path length than the first pair and effective when subjected to a potential difierence to exert a deflecting force in the same plane as said first pair, and means for applying to said first pair an alternating potential difference of constant amplitude and desired scanning periodicity and to said second pair an alternating potential of sirnilar amplitude and periodicity but of reversed direction of action.
• means for projecting an electron beam along a given axis, a fluorescent screen to be scanned by the beam, and deflecting means including two mutually perpendicular electrode systems effective to cause the beam to scan the entire surface of the screen in successive increments, each of said systems including a first pair of oppositely disposed electrodes Opond pair and there being a common source of alternating potential of constant amplitude for energizing both pairs of electrodes whereby the respective electrode pairs are effective to produce opposite oscillatory deflections of the electron 5 beam.

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• Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=41259032

Family Applications (2)

Family Applications After (1)

Country Status (5)

Cited By (9)

Families Citing this family (4)

• 0
  • BE BE431937D patent/BE431937A/xx unknown
• 1936
  • 1936-07-31 GB GB21302/36A patent/GB479064A/en not_active Expired
  • 1936-10-30 GB GB29563/36A patent/GB488188A/en not_active Expired
• 1937
  • 1937-07-28 FR FR824875D patent/FR824875A/fr not_active Expired
  • 1937-07-30 BE BE422914D patent/BE422914A/xx unknown
  • 1937-10-13 US US168820A patent/US2197523A/en not_active Expired - Lifetime
  • 1937-10-29 FR FR48958D patent/FR48958E/fr not_active Expired
• 1938
  • 1938-01-03 GB GB114/38A patent/GB508520A/en not_active Expired
  • 1938-08-04 US US223089A patent/US2212396A/en not_active Expired - Lifetime
  • 1938-12-30 FR FR50137D patent/FR50137E/fr not_active Expired
  • 1938-12-31 DE DEA11145D patent/DE914878C/de not_active Expired

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