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
  • H01J29/70—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
  • H01J29/762—Deflecting by magnetic fields only using saddle coils or printed windings
• • 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
  • H01J29/82—Mounting, supporting, spacing, or insulating electron-optical or ion-optical arrangements
  • H01J29/823—Mounting, supporting, spacing, or insulating electron-optical or ion-optical arrangements around the neck of the tube
  • H01J29/826—Deflection arrangements

Definitions

• the invention relates to a system for deflecting electron beams for cathode ray tubes, and more particularly to the device ensuring both the support of the deflection coils and the mechanical rigidity of the system.
• Such a deflection system also called a deflector, generally consists of a pair of vertical deflection coils, a pair of horizontal deflection coils and a ring of substantially frustoconical shape made of magnetic material intended to concentrate the flow created. by the coils.
• the two pairs of deflection coils are electrically insulated by a separator, generally made of plastic, which also makes it possible to improve the mechanical rigidity of the deflection device, to fix the coils relative to each other and to adjust the together on the neck of the tube.
• the separator consists of a main body, in one or more parts, substantially in the form of a funnel, and a flexible rear part conforming to the neck of the tube and intended to fix the position of the deflection system along the longitudinal axis. tube; this fixing is generally effected by means of a clamping collar placed above the flexible rear part.
• a deviation system is disclosed in the approach of patent EP 690471.
• the deflection coils are installed on the separator and adjusted in position, with respect to each other so as to generate the deflection fields, vertical and horizontal, in accordance with the tube to cathode rays that the deflector is intended to equip.
• the coils After positioning, the coils, in a subsequent step must be fixed definitively, for example by gluing to the body of the separator.
• the main problem consists in maintaining the relative positioning of the coils on the separator between the moment when the adjustment is made and the moment when the coils are definitively fixed on the separator.
• FIG. 1 shows a deflection system also called a deflector, comprising a pair of horizontal deflection coils 3 in the form of a saddle, a pair of vertical deflection coils 4 also in the form of a saddle, isolated from the previous one by a separator 2; a ring of ferromagnetic material 5 is placed around the coils 3 and 4.
• the assembly is arranged on the neck 8 of a cathode ray tube 6, of main axis Z, in order to deflect the electron beams coming from the barrel 7, along the axes X and Y, so that they explore the screen surface 9 of the tube.
• the deflection coils are arranged on the body of the separator and their relative positioning is precisely adjusted so as to generate deflection fields of desired conformation. Once this adjustment has been made, the coils must remain in place until the subsequent stage of final immobilization on the separator, a stage generally carried out by bonding the coils to the body of the separator.
• Figures 2 and 3 show how are maintained, in the prior art, the vertical deflection coils 4 on the separator 2.
• the front 10 of the coils is inserted in the housing formed by the wall of the separator, at least one lug 13 holding the front of the coils and their position along the Z axis, while a tooth 12 ensures the position along the Y axis of the part 10; the rear 11 of the coils is then adjusted against the rear of the substantially cylindrical separator, the whole is then held in position by surrounding the parts 11 with an adhesive 15.
• the two coils are separated by an edge 14 extending in the YZ plan.
• the adjustment of the position of the coils before the bonding phase on the body of the separator can be modified, when manipulating the pre-adjusted deflector, either by the rotation of the front part 11 around the Z axis according to an amplitude 16 depending shapes of the coils and tolerances allowed, ie displacements of the rear 11 in the XY plane, the manufacturing tolerances leaving a gap 17 between the internal surface of 11 and the surface of the separator.
• the deflector according to the invention has a separator whose particularity is to have on at least one of its surfaces the means for positioning and holding a pair of deflection coil, these means ensuring the maintenance of the adjustment. initial coils until the bonding phase of said coils on the separator.
• These means are produced by molding the material of the separator during the production of the latter and therefore do not require the use of adhesive or additional part.
• the blocking of the front part in rotation about the Z axis and in position along the Y axis is ensured by at least two lugs 20 arranged on the surface of the separator 28 such that they each come at at least one point 21 into contact with the coils in the internal window 22 free of conductor.
• the blocking of the front part of each coil is ensured by at least one edge extending over the surface of the separator, so that its ends come into contact with the coil in the window free of conductor of said coil.
• the final design of the deflection coils goes through iteration steps, for example to perfectly adapt the convergence of the electron beams on the screen of the tube; to introduce these modifications, if necessary, without having to modify the mold for manufacturing the separators, an extremely expensive mold to manufacture, it is customary to modify the geometric distribution of the conductors, which involves modifying the shape of the internal window of the coil.
• the means for locking in rotation of the front of the coils are preferably arranged on the surface of the separator so as to come into contact with the coils in the part of the window rather situated towards the front of the separator: thus the designer will be able to introduce changes in the conformation of the fields without it being necessary to move the means of blocking 20 on the body of the separator and therefore having to make a new mold to manufacture said separator.
• the edge 14 for separating the vertical deflection coils is such that its rear part 30 is shaped so as to produce a substantially planar wall 33, parallel to the plane XZ.
• the end 35 of the wall is bevelled so as to favor the insertion of the rear part 30 into the space provided between the wall 33 and the surface of the separator.
• This wall is located at a distance 32 from the surface of the separator, a distance substantially equal to the thickness of the coil which is intended to be housed below.
• This wall may extend on either side of each of the edges 14.
• the rear part of the edge 14 is shaped so as to produce a curved wall 33 substantially parallel to the cylindrical surface of the separator, the curved shape of these walls being adapted to avoid that , by reaction to the stress, the coils do not come out during manipulation of the housing in which they are inserted
• the embodiments described above are not limiting; thus several parts of each of the edges 14 can be shaped to form several walls 33; similarly the means described for positioning and maintaining vertical deflection coils are similarly adapted to horizontal deflection coils provided that they are placed on the internal surface of the separator.

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• Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)

Priority Applications (10)

Applications Claiming Priority (2)

Publications (2)

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Country Status (3)

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• 1996
  • 1996-03-08 EP EP96400495A patent/EP0794551B1/fr not_active Expired - Lifetime
• 1997
  • 1997-02-26 US US08/807,844 patent/US5818159A/en not_active Expired - Fee Related
  • 1997-03-07 JP JP9068970A patent/JPH103865A/ja active Pending

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