CA1075298A - Static convergence device for colour television display tube - Google Patents
Static convergence device for colour television display tubeInfo
- Publication number
- CA1075298A CA1075298A CA273,881A CA273881A CA1075298A CA 1075298 A CA1075298 A CA 1075298A CA 273881 A CA273881 A CA 273881A CA 1075298 A CA1075298 A CA 1075298A
- Authority
- CA
- Canada
- Prior art keywords
- display tube
- colour television
- television display
- ring
- tube
- 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
Links
- 230000003068 static effect Effects 0.000 title claims abstract description 15
- 239000000463 material Substances 0.000 claims abstract description 6
- 230000006698 induction Effects 0.000 claims abstract description 3
- 230000005405 multipole Effects 0.000 claims abstract 2
- 238000010894 electron beam technology Methods 0.000 claims description 13
- 239000012858 resilient material Substances 0.000 claims description 2
- 229910000859 α-Fe Inorganic materials 0.000 description 5
- 239000011521 glass Substances 0.000 description 4
- 238000010276 construction Methods 0.000 description 3
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 description 2
- 229910045601 alloy Inorganic materials 0.000 description 2
- 239000000956 alloy Substances 0.000 description 2
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 241000272470 Circus Species 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 239000003086 colorant Substances 0.000 description 1
- 230000001419 dependent effect Effects 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 229910052742 iron Inorganic materials 0.000 description 1
- 239000000696 magnetic material Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000002311 subsequent effect Effects 0.000 description 1
- 238000007669 thermal treatment Methods 0.000 description 1
- 229910000586 vicalloy Inorganic materials 0.000 description 1
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
- H01J29/701—Systems for correcting deviation or convergence of a plurality of beams by means of magnetic fields at least
- H01J29/702—Convergence correction arrangements therefor
- H01J29/703—Static convergence systems
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2229/00—Details of cathode ray tubes or electron beam tubes
- H01J2229/58—Electron beam control inside the vessel
- H01J2229/581—Electron beam control inside the vessel by magnetic means
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
- H01J2229/00—Details of cathode ray tubes or electron beam tubes
- H01J2229/58—Electron beam control inside the vessel
- H01J2229/583—Electron beam control inside the vessel at the source
- H01J2229/5835—Electron beam control inside the vessel at the source cooperating with the electron gun
Landscapes
- Video Image Reproduction Devices For Color Tv Systems (AREA)
- Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
Abstract
ABSTRACT
In a colour television display tube, an air gapped permanent magnet ring is mounted on the electron gun in the tube neck and magnetized from outside the tube to provide a multipole magnetic field for correction of static misconvergence. The magnet material has average values of coercive field strength of 5 to 40 kA/m and average values of remanent induction of 500 to 1500 milli-telsa.
In a colour television display tube, an air gapped permanent magnet ring is mounted on the electron gun in the tube neck and magnetized from outside the tube to provide a multipole magnetic field for correction of static misconvergence. The magnet material has average values of coercive field strength of 5 to 40 kA/m and average values of remanent induction of 500 to 1500 milli-telsa.
Description
~C~75298 The invention relates to a colour television display tube having a device for the correction of the static convergence for a colour television display tube, a magnetisable permanent magnetic ring being provided inside the neck of the tube.
A colour television display tube having a device for the correction of the static convergence is described in an article in "Philips Product Information Electronic Components and Materials", No. 58, entitled "20 AX for 110 colour television". A similar construction is to be found in the publication of Valvo "Spezielle Bauelemente fur das 20 AX-System", "Technische Daten", April, 1974.
U.S. Patent 3,725,831, which issued to RCA Corp. on April 3, 1973, discloses a colour television display tube operating with three beams and having a correction device which is arranged around the neck of said colour television display tube. Said U.S.
Patent shows separately adjustable magnets in combination with field-conductive poleshoe constructions, the magnets being situated outside the display tube and the poleshoes being situated partly within the neck of the tube.
Furthermore there is a prior U.S. Patent 4,105,983 which issued to U.S. Philips Corp. on August 8, 1978, which describes both a method of manufacturing a static convergence device and such a convergence device in a colour television display tube, in which magnetisable rings are used which may be arranged outside or inside the neck of the colour television display tube. Said prior U.S. Patent 4,105,983 describes a magnetisable ferrite ring which is arranged inside the neck, .` ~
B
~075298 so in a vacuum. As is described in the further specification of the magnetisation device, said ferrite ring may be magnetised multipolarly a~ its circumference but preferably prior to the provision thereof in the tube. However, this impedes a directed S and accurate adjustement of the required correction field. As a matter of fact, due to its high coercive field strength, a ferrite ring can be magnetised only by very strong magnetic fields. However, such strong magnetic fields are difficult to produce from without through the glass in a ferrite ring provided in a vacuum. In addition, when no other measures are taken, the danger exists in a ceramic ferrite ring provided in the vacuum of the tube that the cathodes of the electron gun are poisoned and become useless.
However, it is suggested in the said prior U.S.
Patent 4,105,983 to provide the permanent magnets as close as possible to the electron beams to be deflected so that on the one hand the poleshoes conducting the magnetic flux can be avoided and on the other hand the magnetic field need no longer be so large because it is provided very close to the deflection plane because as a matter of fact the stray field losses become considerably smaller.
The invention starts from this prior art and has for its object to provide an improvement of the mag-netisable permanent magnetic ring as described in the above-mentioned prior U.S. Patent 4,105,933 and arranged in the neck PlID 7G-~O
28.2.1977 of t}le tube and w}Iich is harmless to the cathode and eI~aI~l~s a directed magnetisatioIl from outside the neck.
Another object of the invention is to give said ring a particularly simple construction and to perform the provision in the tube of said ring in such manner that no difficulties can occur upon assembling the colour television display tube.
According to the invention this is achieved in that in a colour television display tube having a device of the kind mentioned in the preamble at least one metallic permanent magnet which can be magnetised or demagnetised in a directed manner from without to a giv~n magnetic stray field strength is provided on or in the electron gun.
According to a further embodiment of the invention the permanent magnet for correcting the convergence may be constructed as a ring which has an air gap at its circumference and which consists of a resilient material.
The rings may furthermore be constructad as wire-shaped or ribbon-shaped rings. According to the invention the material of the permanent magnets can be adjusted at accurately determined magnetic properties with small tolerances by a directed thermal treatment, for example, with average values o~f the coercive field strength BHC of 5 to 40 kA/m and average values of the remanent induction of 500 to 1500 mT. ~urthermore, the rings may be magnetised at their circumference with six or twelve poles with a strength which is the same or differs for each pole pair.
At least each time one ring may be provided at an axial distance of at least 15 mm on the electron gun for PIID ~6-o60 28.2 1977 ~.075298 the corrcction of the static convergence. According to another embodiment of the invention the permanent magnetic ring and the permanent magnetic ribbon, respectively, may be provided at the level of the grids 3 on the electron gun and/or on the contact lugs at the end of the electron gun facing the display screen and/or in the centering sleeve of the said gun. Alternatively, two six-pole magnetised permanent magnetic rings and permanent magnetic ribbons, respectively, may also be juxtaposed, one of which is provided so as to be shifted over 30 with respect to the other for generating with its magnet poles a twelve-pole field at the circumference.
The said devices are possible because in the known electron guns sufficient space for building-in said rings is available. The advantage of the air gap in the ring is that the ring can easily be bent apart so that upon providing it can be slid over that part of the said gun which has the smallest radial dimension. It is most favourable to provide the ring at the level of the grid (3) because the strongest deflection effect can be obtained at that area with the least possible effort.
When all the rings, so both the rings which are to be provided at the level of the grid 3 and the rings which are to be provided on the contact lugs, are constructed in the same manner, they can be held in place very simply and be assembled. When the rings are constructed in the form of ribbons, another field distribution can in some cases better be realised. The use of materials for the metallic permanent magnets with a comparatively low coercive PHD 76-o60 28.2.1977 field strength has the advantage that magnetisation and then directed de~nagnetisation can be carried out with com-paratively small field strengths, namely from the ou~side in the otherwise fully assembled tube. The magnetic fields required for magnetisation and demagnetisation thus are effective through the glass of the neck of the tube and two to twelve-pole magnetic polarisations can be adjusted at the circumference of the permanent magnetic ring(s) or ribbon(s), The invention will now be described in greater detail with reference to the accompanying drawings, in which, Fig. 1 is a side elevation of an eiectron gun for a colour display tube according to the invention, Fig. 2 is a partial elevation of the electron gun shown in Fig. 1 in a side elevation perpendicular to that shown in Fig. 1, Fig. 3 is a plan view of an electron gun shown in Fig. 1 taken on the line III-III in Fig. 1, ~ Fig. 4 shows a magnetisation device for the magnetisation and the directed demagnetisation of the permanent magnetic ring according to the invention, and Fig. 5 shows a deflection diagram to explain the operatioll of the correction of the static convergence, and Fig. 6 shows a colour display tube according to the invention.
Reference numeral 1 in Fig. 1 denotes a tube socket of compressed glass through which the individual electrodes for the electron gun are passed, the gun being denoted by the common reference numeral 2. Such an electron gun is known per se and need not be described in detail.
Shown in Fig. 1 approximately centrally of the axial dimension of the electron gun is the grid which is denoted by reference numeral 3. At the level of the grid 3 is provided the one multipolarly magnetisable wire-shaped ring which has an air gap at its circumference and consists of the resilient permanent magnetic material (denoted by 4).
It serves for the correction of the static convergence. At the end of the electron gun facing the display screen, centering springs 5 are situated and the second multipolarly magnetisable wire-shaped ring may be provided around said centering springs 5. It is denoted by 6 in the figure.
Said magnetisable permanent magnetic ring 6 for further correction of the static convergence may alternatively be provided in the centering sleeve 27. It may engage said sleeve in a clamping manner from within, as is denoted by 28 in Fig. 1. According to a preferred embodiment the rings consist of wire, for example having a diameter of 1.5 mm.
The operation of the permanent magnetic ring 6 is such that after its accurate adjustment, the sub-sequent adjustments for a dynamic convergence can also be carried out with less effort and may in some cases be omitted entirely.
The outside diameter of the rings is approxi-mately 31 mm and their inside diameter is 28 mm. The rings preferably consist of the material "Vicalloy", which is a registered trade mark, having the alloy components Fe, Co, ~, Cr of an alloy which is particularly suitable for drawing operations and with which wires can ~075Z98 PHD 76-060 be manufactured with a maximum density of magnetic energy (B.HmaX) of 15.9 to 23.9 kJ/m3 and with a remanence Br f 1000 to 1200 mT, wherein "mT" means "milli-tesla", and a coercive field strength BHC of 24 to 32 kA/m.
The electron gun shown in Fig. 1 is the gun which is used for a so-called in-line-tube, which means that the electron guns are situated in the same plane, that is the plane which is shown in Fig. 1 at right angles to the plane of the drawing. Therefore, Fig. 2 again shows the elevation at right angles thereto. This figure shows the three grids 3 of the three electron suns for red, green and blue, at the level of which the magnetisable permanent magnetic ring for correcting the static con-vergence is provided. So Fig. 2 lies in the plane of the three electron guns.
Fig. 3 is a plan view of the electron gun taken on the line III-III of Fig. 1. This plan view again shows the three electron guns which need not be described further. Said plan view also shows the air gap which is denoted by 7 and which is situated at the circumference of the magnetisable permanent magnetic ring according to the invention. The said air gap may be approximately 1 mm.
Fig. 4 finally shows a magnetisation device equal to that shown in Fig. 3 as described in the prior U.S. Patent 4,10~,983. The permanent magnetic rings 4 and 6, respectively, are thus clamped on the electron gun at a distance from the inner wall of the neck 8 of the tube, as is shown in Figs. 1 and 2 and 3, respectively, and after assembly and evacuating the tube, a magnetisation device can now be slid from the rear over the neck of the tube, which device is denoted by the common reference ~, numeral 9. It consists of an iron ring around which the individual coils 11 are wound. Such a current can be passed through said coils that poles are formed on the inwardly projecting limbs 12 so that the permanent magnetic ring at its circu~ference is mult;polarly magnetized, so in this case with six poles, and alternately north and south poles are formed therein. The magnetisation device is constructed so that the individual pole pairs need not be equal to each other because the magnetisation current is adjusted in a directed manner, as is described in detail in the above-mentioned prior U.S. Patent 4,105,983. Dependent upon the adjusted convergence need, the permanent magnetic ring is, for example, magnetised with six poles by accurately adjusted current pulses through the coils 11. The current pulses may be different for each individual coil as regards direction and value. However, it is alternatively possible in a first process step to magnetise the wire-shaped ring by a strong current pulse with six poles to saturation with the correct polarity. In a subsequent adjusting process step the wire-shaped ring is then demagnetised by directed reverse current pulses so strongly that the convergence correction is optimum. The demagnetisation may also be carried out with a 50 Hz alternating field slowly with an amplitude increasing to the optimum value.
The embodiment shown in Fig. 4 shows a device for a six-pole magnetisation, a corresponding device for eight-pole, twelve-pole or four-pole magnetisation then has a correspondingly different subdivision. In principle, .~ t P~lD 76-o60 28.2.1977 however, this is not essentially different from the device shown.
~ig. 5 finally shows the realised deflection.
- The plane 13 is the cathode plane, the plane 14 is the plane of the grid 3 for the correction of the static convergence, the plane 15 is the centering plane for the further correction of the static convergence and the plane 16 is the deflection plane, hence the plane in which the deflection coils are situated namely for the frame and line deflection. Reference numeral 17 finally denotes the plane of the display screen. An electron beam might have for example, the following variation:
It is assumed that two errors occur. It would be ideal if the electron beam would directly land on point 20 from point 19 but because the system shows an undesired parallel shifting, the electron beam is to land on point 21. This can be achieved by means of the ring for the correction of the static convergence in the plane of the grid 3j namely in the plane 14. By means of the ring 4 according to the invention, actually, a magnetic field is generated whiçh deflects the electron beam in the plane 14, hence in point 22, in such manner that it lands correctly on point 21.
It then has the variation denoted by 23. However, said electron beam is not yet fully corrected. In the deflection plane, namely in the plane denoted at~ 16, the magnetic field of the deflection coils is operative which deflects the electron beam again from the correct landing position in the outermost zones of the screen. ~ewer dynamic con-vergence errors would occur when the electron beam traverses . . . .
--~0--PIID 76-0~0
A colour television display tube having a device for the correction of the static convergence is described in an article in "Philips Product Information Electronic Components and Materials", No. 58, entitled "20 AX for 110 colour television". A similar construction is to be found in the publication of Valvo "Spezielle Bauelemente fur das 20 AX-System", "Technische Daten", April, 1974.
U.S. Patent 3,725,831, which issued to RCA Corp. on April 3, 1973, discloses a colour television display tube operating with three beams and having a correction device which is arranged around the neck of said colour television display tube. Said U.S.
Patent shows separately adjustable magnets in combination with field-conductive poleshoe constructions, the magnets being situated outside the display tube and the poleshoes being situated partly within the neck of the tube.
Furthermore there is a prior U.S. Patent 4,105,983 which issued to U.S. Philips Corp. on August 8, 1978, which describes both a method of manufacturing a static convergence device and such a convergence device in a colour television display tube, in which magnetisable rings are used which may be arranged outside or inside the neck of the colour television display tube. Said prior U.S. Patent 4,105,983 describes a magnetisable ferrite ring which is arranged inside the neck, .` ~
B
~075298 so in a vacuum. As is described in the further specification of the magnetisation device, said ferrite ring may be magnetised multipolarly a~ its circumference but preferably prior to the provision thereof in the tube. However, this impedes a directed S and accurate adjustement of the required correction field. As a matter of fact, due to its high coercive field strength, a ferrite ring can be magnetised only by very strong magnetic fields. However, such strong magnetic fields are difficult to produce from without through the glass in a ferrite ring provided in a vacuum. In addition, when no other measures are taken, the danger exists in a ceramic ferrite ring provided in the vacuum of the tube that the cathodes of the electron gun are poisoned and become useless.
However, it is suggested in the said prior U.S.
Patent 4,105,983 to provide the permanent magnets as close as possible to the electron beams to be deflected so that on the one hand the poleshoes conducting the magnetic flux can be avoided and on the other hand the magnetic field need no longer be so large because it is provided very close to the deflection plane because as a matter of fact the stray field losses become considerably smaller.
The invention starts from this prior art and has for its object to provide an improvement of the mag-netisable permanent magnetic ring as described in the above-mentioned prior U.S. Patent 4,105,933 and arranged in the neck PlID 7G-~O
28.2.1977 of t}le tube and w}Iich is harmless to the cathode and eI~aI~l~s a directed magnetisatioIl from outside the neck.
Another object of the invention is to give said ring a particularly simple construction and to perform the provision in the tube of said ring in such manner that no difficulties can occur upon assembling the colour television display tube.
According to the invention this is achieved in that in a colour television display tube having a device of the kind mentioned in the preamble at least one metallic permanent magnet which can be magnetised or demagnetised in a directed manner from without to a giv~n magnetic stray field strength is provided on or in the electron gun.
According to a further embodiment of the invention the permanent magnet for correcting the convergence may be constructed as a ring which has an air gap at its circumference and which consists of a resilient material.
The rings may furthermore be constructad as wire-shaped or ribbon-shaped rings. According to the invention the material of the permanent magnets can be adjusted at accurately determined magnetic properties with small tolerances by a directed thermal treatment, for example, with average values o~f the coercive field strength BHC of 5 to 40 kA/m and average values of the remanent induction of 500 to 1500 mT. ~urthermore, the rings may be magnetised at their circumference with six or twelve poles with a strength which is the same or differs for each pole pair.
At least each time one ring may be provided at an axial distance of at least 15 mm on the electron gun for PIID ~6-o60 28.2 1977 ~.075298 the corrcction of the static convergence. According to another embodiment of the invention the permanent magnetic ring and the permanent magnetic ribbon, respectively, may be provided at the level of the grids 3 on the electron gun and/or on the contact lugs at the end of the electron gun facing the display screen and/or in the centering sleeve of the said gun. Alternatively, two six-pole magnetised permanent magnetic rings and permanent magnetic ribbons, respectively, may also be juxtaposed, one of which is provided so as to be shifted over 30 with respect to the other for generating with its magnet poles a twelve-pole field at the circumference.
The said devices are possible because in the known electron guns sufficient space for building-in said rings is available. The advantage of the air gap in the ring is that the ring can easily be bent apart so that upon providing it can be slid over that part of the said gun which has the smallest radial dimension. It is most favourable to provide the ring at the level of the grid (3) because the strongest deflection effect can be obtained at that area with the least possible effort.
When all the rings, so both the rings which are to be provided at the level of the grid 3 and the rings which are to be provided on the contact lugs, are constructed in the same manner, they can be held in place very simply and be assembled. When the rings are constructed in the form of ribbons, another field distribution can in some cases better be realised. The use of materials for the metallic permanent magnets with a comparatively low coercive PHD 76-o60 28.2.1977 field strength has the advantage that magnetisation and then directed de~nagnetisation can be carried out with com-paratively small field strengths, namely from the ou~side in the otherwise fully assembled tube. The magnetic fields required for magnetisation and demagnetisation thus are effective through the glass of the neck of the tube and two to twelve-pole magnetic polarisations can be adjusted at the circumference of the permanent magnetic ring(s) or ribbon(s), The invention will now be described in greater detail with reference to the accompanying drawings, in which, Fig. 1 is a side elevation of an eiectron gun for a colour display tube according to the invention, Fig. 2 is a partial elevation of the electron gun shown in Fig. 1 in a side elevation perpendicular to that shown in Fig. 1, Fig. 3 is a plan view of an electron gun shown in Fig. 1 taken on the line III-III in Fig. 1, ~ Fig. 4 shows a magnetisation device for the magnetisation and the directed demagnetisation of the permanent magnetic ring according to the invention, and Fig. 5 shows a deflection diagram to explain the operatioll of the correction of the static convergence, and Fig. 6 shows a colour display tube according to the invention.
Reference numeral 1 in Fig. 1 denotes a tube socket of compressed glass through which the individual electrodes for the electron gun are passed, the gun being denoted by the common reference numeral 2. Such an electron gun is known per se and need not be described in detail.
Shown in Fig. 1 approximately centrally of the axial dimension of the electron gun is the grid which is denoted by reference numeral 3. At the level of the grid 3 is provided the one multipolarly magnetisable wire-shaped ring which has an air gap at its circumference and consists of the resilient permanent magnetic material (denoted by 4).
It serves for the correction of the static convergence. At the end of the electron gun facing the display screen, centering springs 5 are situated and the second multipolarly magnetisable wire-shaped ring may be provided around said centering springs 5. It is denoted by 6 in the figure.
Said magnetisable permanent magnetic ring 6 for further correction of the static convergence may alternatively be provided in the centering sleeve 27. It may engage said sleeve in a clamping manner from within, as is denoted by 28 in Fig. 1. According to a preferred embodiment the rings consist of wire, for example having a diameter of 1.5 mm.
The operation of the permanent magnetic ring 6 is such that after its accurate adjustment, the sub-sequent adjustments for a dynamic convergence can also be carried out with less effort and may in some cases be omitted entirely.
The outside diameter of the rings is approxi-mately 31 mm and their inside diameter is 28 mm. The rings preferably consist of the material "Vicalloy", which is a registered trade mark, having the alloy components Fe, Co, ~, Cr of an alloy which is particularly suitable for drawing operations and with which wires can ~075Z98 PHD 76-060 be manufactured with a maximum density of magnetic energy (B.HmaX) of 15.9 to 23.9 kJ/m3 and with a remanence Br f 1000 to 1200 mT, wherein "mT" means "milli-tesla", and a coercive field strength BHC of 24 to 32 kA/m.
The electron gun shown in Fig. 1 is the gun which is used for a so-called in-line-tube, which means that the electron guns are situated in the same plane, that is the plane which is shown in Fig. 1 at right angles to the plane of the drawing. Therefore, Fig. 2 again shows the elevation at right angles thereto. This figure shows the three grids 3 of the three electron suns for red, green and blue, at the level of which the magnetisable permanent magnetic ring for correcting the static con-vergence is provided. So Fig. 2 lies in the plane of the three electron guns.
Fig. 3 is a plan view of the electron gun taken on the line III-III of Fig. 1. This plan view again shows the three electron guns which need not be described further. Said plan view also shows the air gap which is denoted by 7 and which is situated at the circumference of the magnetisable permanent magnetic ring according to the invention. The said air gap may be approximately 1 mm.
Fig. 4 finally shows a magnetisation device equal to that shown in Fig. 3 as described in the prior U.S. Patent 4,10~,983. The permanent magnetic rings 4 and 6, respectively, are thus clamped on the electron gun at a distance from the inner wall of the neck 8 of the tube, as is shown in Figs. 1 and 2 and 3, respectively, and after assembly and evacuating the tube, a magnetisation device can now be slid from the rear over the neck of the tube, which device is denoted by the common reference ~, numeral 9. It consists of an iron ring around which the individual coils 11 are wound. Such a current can be passed through said coils that poles are formed on the inwardly projecting limbs 12 so that the permanent magnetic ring at its circu~ference is mult;polarly magnetized, so in this case with six poles, and alternately north and south poles are formed therein. The magnetisation device is constructed so that the individual pole pairs need not be equal to each other because the magnetisation current is adjusted in a directed manner, as is described in detail in the above-mentioned prior U.S. Patent 4,105,983. Dependent upon the adjusted convergence need, the permanent magnetic ring is, for example, magnetised with six poles by accurately adjusted current pulses through the coils 11. The current pulses may be different for each individual coil as regards direction and value. However, it is alternatively possible in a first process step to magnetise the wire-shaped ring by a strong current pulse with six poles to saturation with the correct polarity. In a subsequent adjusting process step the wire-shaped ring is then demagnetised by directed reverse current pulses so strongly that the convergence correction is optimum. The demagnetisation may also be carried out with a 50 Hz alternating field slowly with an amplitude increasing to the optimum value.
The embodiment shown in Fig. 4 shows a device for a six-pole magnetisation, a corresponding device for eight-pole, twelve-pole or four-pole magnetisation then has a correspondingly different subdivision. In principle, .~ t P~lD 76-o60 28.2.1977 however, this is not essentially different from the device shown.
~ig. 5 finally shows the realised deflection.
- The plane 13 is the cathode plane, the plane 14 is the plane of the grid 3 for the correction of the static convergence, the plane 15 is the centering plane for the further correction of the static convergence and the plane 16 is the deflection plane, hence the plane in which the deflection coils are situated namely for the frame and line deflection. Reference numeral 17 finally denotes the plane of the display screen. An electron beam might have for example, the following variation:
It is assumed that two errors occur. It would be ideal if the electron beam would directly land on point 20 from point 19 but because the system shows an undesired parallel shifting, the electron beam is to land on point 21. This can be achieved by means of the ring for the correction of the static convergence in the plane of the grid 3j namely in the plane 14. By means of the ring 4 according to the invention, actually, a magnetic field is generated whiçh deflects the electron beam in the plane 14, hence in point 22, in such manner that it lands correctly on point 21.
It then has the variation denoted by 23. However, said electron beam is not yet fully corrected. In the deflection plane, namely in the plane denoted at~ 16, the magnetic field of the deflection coils is operative which deflects the electron beam again from the correct landing position in the outermost zones of the screen. ~ewer dynamic con-vergence errors would occur when the electron beam traverses . . . .
--~0--PIID 76-0~0
2~.2.1977 the plane 16 at right angles. However, it would then go from point 24 at right angles to point 21. Therefore, an over-compensation in the plane 14 must take place by means of the ring 4, in order that the electron beam land in the plane 15 on point 24 and if no correction takes place the bearn would land on point 25 in the picture display plane 17.
However, the ring 6 according to the invention serves for the second correction. It deflects the electron beam back again so that it then traverses the paths which are denoted by 26 in Fig. 5 at right angles and hence passes through the deflection plane 16 also at right angles.
Fig. 6 is a diagrammatic sectional view of a colour display tube according to the invention. Inside a glass envelope 31, which is composed of a conical part 32, a display window 33 and a neck 34, and in front of the screen 36 which consists of a large number of triplets of phosphor stripes luminescing in three different colours which are at right angles to the plane of the drawing, is situated the shadow mask 35 which has a very large number of apertures 37 which are rectangular in the direction of the phosphor stripes. The electron beams 38, 39 and 40 from the electron gun 41 pass through said apertures 37, said electron beams being situated in the plane of the drawing and being deflected by the system 42 of deflection coils. The tube has a good static convergence when the rings according to the invention are used.
However, the ring 6 according to the invention serves for the second correction. It deflects the electron beam back again so that it then traverses the paths which are denoted by 26 in Fig. 5 at right angles and hence passes through the deflection plane 16 also at right angles.
Fig. 6 is a diagrammatic sectional view of a colour display tube according to the invention. Inside a glass envelope 31, which is composed of a conical part 32, a display window 33 and a neck 34, and in front of the screen 36 which consists of a large number of triplets of phosphor stripes luminescing in three different colours which are at right angles to the plane of the drawing, is situated the shadow mask 35 which has a very large number of apertures 37 which are rectangular in the direction of the phosphor stripes. The electron beams 38, 39 and 40 from the electron gun 41 pass through said apertures 37, said electron beams being situated in the plane of the drawing and being deflected by the system 42 of deflection coils. The tube has a good static convergence when the rings according to the invention are used.
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS
1. A colour television display tube comprising a neck, an electron gun means disposed in said neck for generating a plurality of electron beams, a display screen opposite said gun, and means disposed within said neck for correcting static con-vergence, said correcting means comprising at least one permanent magnet which has been magnetized from outside said tube to provide a multipole magnetic field, said magnet comprising a material having average values of coercive field strength of 5 to 40 kA/m and average values of remanent induction of 500 to 1500 mT
(milli-tesla).
(milli-tesla).
2. A colour television display tube as claimed in Claim 1, characterized in that the permanent magnet for the correction of the convergence is constructed as a ring which has an air gap at its circumference and which consists of a resilient material.
3. A colour television display tube as claimed in Claim 2, characterized in that the permanent magnet is constructed as a wire-shaped or ribbon-shaped ring.
4. A colour television display tube as claimed in Claim 2, characterized in that the ring is magnetised at the circumference with six poles or twelve poles with a strength which is the same or different for each pole pair..
5. A colour television display tube as claimed in Claim 3, characterized in that the permanent magnetic ring or the permanent magnetic ribbon is clamped on the electron gun at the location of grids of the electron gun.
6. A colour television display tube as claimed in Claim 3, characterized in that the permanent magnetic ring or the permanent magnetic ribbon, is clamped on contact lugs at the end of the electron gun facing the display screen.
7. A colour television display tube as claimed in Claim 3, characterized in that the permanent magnetic ring or the per-manent magnetic ribbon, is provided in the centering sleeve of the electron gun.
8. A colour television display tube as claimed in Claim 3, characterized in that two six-pole magnetised permanent magnets (rings or ribbons) are juxtaposed, one of which is provided so as to be shifted over an angle of 30° with respect to the other to generate with its magnet poles a twelve-pole field at the circum-ference.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE19762612607 DE2612607C3 (en) | 1976-03-25 | 1976-03-25 | Static convergence correction device in color television picture display tubes |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1075298A true CA1075298A (en) | 1980-04-08 |
Family
ID=5973364
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA273,881A Expired CA1075298A (en) | 1976-03-25 | 1977-03-14 | Static convergence device for colour television display tube |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS52117517A (en) |
| AU (1) | AU506881B2 (en) |
| BE (1) | BE852807A (en) |
| CA (1) | CA1075298A (en) |
| DE (1) | DE2612607C3 (en) |
| ES (1) | ES457148A1 (en) |
| FR (1) | FR2345805A1 (en) |
| GB (1) | GB1540817A (en) |
| HK (1) | HK66279A (en) |
| NL (1) | NL176115C (en) |
Families Citing this family (32)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2722477A1 (en) * | 1977-05-18 | 1978-11-23 | Standard Elektrik Lorenz Ag | COLOR TELEVISION SCREENS |
| JPS5832378Y2 (en) * | 1977-06-23 | 1983-07-18 | 松下電器産業株式会社 | Convergence device |
| NL7707476A (en) * | 1977-07-06 | 1979-01-09 | Philips Nv | PROCEDURE FOR MANUFACTURING A COLOR IMAGE TUBE AND COLOR IMAGE TUBE MADE IN ACCORDANCE WITH THAT PROCESS. |
| US4138628A (en) * | 1977-07-26 | 1979-02-06 | Rca Corporation | Magnetizing method for use with a cathode ray tube |
| US4201932A (en) * | 1978-02-06 | 1980-05-06 | Rca Corporation | Color purity adjusting method |
| JPS554807A (en) * | 1978-06-24 | 1980-01-14 | Mitsubishi Electric Corp | Neck magnet of braun tube |
| DE2840211C2 (en) * | 1978-09-15 | 1982-11-11 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | Device for setting the convergence and color purity of a color picture tube |
| DE2903734C2 (en) * | 1979-02-01 | 1982-11-04 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | Method for adjusting convergence and color purity in color picture tubes |
| JPS55108154A (en) * | 1979-02-14 | 1980-08-19 | Toshiba Corp | Color picture tube apparatus |
| NL181895C (en) * | 1979-10-02 | 1987-11-16 | Philips Nv | CATHODE JET TUBE WITH CORRECTION RINGS MULTIPOLO MAGNETIZED. |
| NL7907717A (en) * | 1979-10-19 | 1981-04-22 | Philips Nv | DEVICE FOR DISPLAYING COLORED IMAGES. |
| JPS5667138A (en) * | 1979-11-06 | 1981-06-06 | Toshiba Corp | Manufacturing method of color picture tube |
| JPS5667144A (en) * | 1979-11-06 | 1981-06-06 | Toshiba Corp | Manufacturing method of color picture tube |
| DE2949851C2 (en) * | 1979-12-12 | 1982-09-09 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | Device for magnetizing a convergence device for inline color picture tubes |
| DE3003197A1 (en) * | 1980-01-30 | 1981-08-06 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | DEVICE FOR ADJUSTING THE ELECTRON BEAMS OF A COLOR IMAGE TUBE |
| JPS57134837A (en) * | 1981-02-16 | 1982-08-20 | Toshiba Corp | Manufacture of color picture tube |
| DE3219954A1 (en) * | 1982-05-27 | 1983-12-01 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | COLOR IMAGE TUBES WITH TWIST CORRECTION |
| DE3123301C2 (en) * | 1981-06-12 | 1985-08-08 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | Device for adjusting electron beams from a cathode ray tube |
| DE3123298A1 (en) * | 1981-06-12 | 1983-01-05 | Standard Elektrik Lorenz Ag, 7000 Stuttgart | CATHODE RAY TUBES WITH MAGNETIC RING |
| JPS58128551U (en) * | 1982-02-24 | 1983-08-31 | 日本電気株式会社 | Color cathode ray tube equipment |
| JPS58128550U (en) * | 1982-02-24 | 1983-08-31 | 日本電気株式会社 | Color cathode ray tube equipment |
| DE3271747D1 (en) * | 1982-03-31 | 1986-07-24 | Ibm | Convergence unit for in-line colour cathode ray tube |
| JPS5983362A (en) * | 1982-11-04 | 1984-05-14 | Matsushita Electric Ind Co Ltd | sealed lead acid battery |
| JPS60112073U (en) * | 1983-12-29 | 1985-07-29 | 株式会社ユアサコーポレーション | Electrode plates for lead-acid batteries |
| NL8500786A (en) * | 1985-03-19 | 1986-10-16 | Philips Nv | METHOD FOR THE MANUFACTURE OF A CATHODE JET TUBE |
| NL8500807A (en) * | 1985-03-20 | 1986-10-16 | Philips Nv | PICTURE TUBE. |
| NL8500862A (en) * | 1985-03-25 | 1986-10-16 | Philips Nv | METHOD FOR MANUFACTURING A COLOR IMAGE TUBE AND APPARATUS FOR CARRYING OUT THIS METHOD |
| GB8611321D0 (en) * | 1986-05-09 | 1986-06-18 | Philips Nv | Correcting electron beam misconvergance |
| JPS6343243A (en) * | 1986-08-07 | 1988-02-24 | Nec Kansai Ltd | Cathode-ray tube |
| JPS6372041A (en) * | 1986-09-16 | 1988-04-01 | Matsushita Electronics Corp | Manufacture of magnet built-in cathode-ray tube |
| JP2937386B2 (en) * | 1990-03-08 | 1999-08-23 | 株式会社東芝 | Method of manufacturing color picture tube |
| JPH088077B2 (en) * | 1990-06-18 | 1996-01-29 | 株式会社東芝 | Cathode ray tube |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2544875A (en) * | 1950-03-02 | 1951-03-13 | Pye Ltd | Combination centering, focusing, and deflecting device for beam of cathode-ray tubes |
| DE961735C (en) * | 1953-03-19 | 1957-04-11 | Fernseh Gmbh | Method for centering the electron beam, especially for television picture tubes, with a permanent magnet surrounding the beam axis in a ring shape and arrangement for carrying out the method |
| US3217200A (en) * | 1962-01-23 | 1965-11-09 | Gen Electric | Internal magnetic lens for electron beams |
| US3316432A (en) * | 1963-11-13 | 1967-04-25 | Gen Electric | Cathode ray tube electron gun mount with unitary magnetic centering and gettering means |
| US3725831A (en) * | 1972-01-14 | 1973-04-03 | Rca Corp | Magnetic beam adjusting arrangements |
| JPS5035769A (en) * | 1973-07-31 | 1975-04-04 | ||
| NL170683C (en) * | 1975-04-01 | 1982-12-01 | Philips Nv | METHOD FOR MANUFACTURING A STATIC CONVERGENCE UNIT AND A COLOR IMAGE TUBE INCLUDING A CONVERGENCE UNIT, MANUFACTURED USING THAT METHOD |
-
1976
- 1976-03-25 DE DE19762612607 patent/DE2612607C3/en not_active Expired
-
1977
- 1977-03-14 CA CA273,881A patent/CA1075298A/en not_active Expired
- 1977-03-22 GB GB1196577A patent/GB1540817A/en not_active Expired
- 1977-03-22 NL NL7703075A patent/NL176115C/en not_active IP Right Cessation
- 1977-03-22 AU AU23495/77A patent/AU506881B2/en not_active Expired
- 1977-03-23 BE BE176059A patent/BE852807A/en not_active IP Right Cessation
- 1977-03-23 ES ES457148A patent/ES457148A1/en not_active Expired
- 1977-03-24 JP JP3166877A patent/JPS52117517A/en active Granted
- 1977-03-25 FR FR7709009A patent/FR2345805A1/en active Granted
-
1979
- 1979-09-13 HK HK66279A patent/HK66279A/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| NL176115B (en) | 1984-09-17 |
| JPS5731784B2 (en) | 1982-07-07 |
| NL7703075A (en) | 1977-09-27 |
| ES457148A1 (en) | 1978-03-01 |
| GB1540817A (en) | 1979-02-14 |
| BE852807A (en) | 1977-09-23 |
| AU506881B2 (en) | 1980-01-24 |
| AU2349577A (en) | 1978-09-28 |
| FR2345805A1 (en) | 1977-10-21 |
| NL176115C (en) | 1985-02-18 |
| HK66279A (en) | 1979-09-21 |
| JPS52117517A (en) | 1977-10-03 |
| DE2612607C3 (en) | 1984-01-12 |
| DE2612607A1 (en) | 1977-10-06 |
| FR2345805B1 (en) | 1980-04-18 |
| DE2612607B2 (en) | 1979-12-13 |
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| Date | Code | Title | Description |
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| MKEX | Expiry |