GB1597741A - Television deflection unit - Google Patents

Television deflection unit Download PDF

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Publication number
GB1597741A
GB1597741A GB14733/78A GB1473378A GB1597741A GB 1597741 A GB1597741 A GB 1597741A GB 14733/78 A GB14733/78 A GB 14733/78A GB 1473378 A GB1473378 A GB 1473378A GB 1597741 A GB1597741 A GB 1597741A
Authority
GB
United Kingdom
Prior art keywords
ring
magnetic ring
deflection unit
screw
coils
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
Application number
GB14733/78A
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
Original Assignee
Philips Gloeilampenfabrieken NV
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Philips Gloeilampenfabrieken NV filed Critical Philips Gloeilampenfabrieken NV
Publication of GB1597741A publication Critical patent/GB1597741A/en
Expired legal-status Critical Current

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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
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/70—Electron beam control outside the vessel
    • H01J2229/703—Electron beam control outside the vessel by magnetic fields
    • H01J2229/7031—Cores for field producing elements, e.g. ferrite

Landscapes

  • Manufacture Of Electron Tubes, Discharge Lamp Vessels, Lead-In Wires, And The Like (AREA)
  • Details Of Television Scanning (AREA)
  • Formation Of Various Coating Films On Cathode Ray Tubes And Lamps (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)

Description

(54) TELEVISION DEFLECTION UNIT (71) We, N.V. PHILIPS' GLOEIL AMPENFABRIEKEN, a limited liability Comapny, organised and established under the laws of the Kingdom of the Netherland, of Emmasingel 29, Eindhoven, the Netherlands, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement::- The invention relates to a deflection unit for a cathode ray tube comprising a frame adapted to embrace portions of the cone and neck of a cathode ray tube, a system of coils consisting of a set of horizontal and a set of vertical deflection coils supported by the frame, and a soft-magnetic ring surrounding the active part of the system of coils, the frame comprising adjusting means for displacing the magnetic ring relative to the deflection coils in a direction perpendicular to the axis longitudinal of the deflection unit, and means for retaining the magnetic ring in position in its axial direction.
The invention also relates to a cathode ray tube having such a deflection unit.
In colour television receivers the deflection unit is used to simultaneously deflect three electron beams, in whilst a convergence device and a device for adjusting the colour purity may also be provided behind the deflection unit. It has been found that in such deflection units for colour television receivers the convergence is very difficult to adjust and that it can often be adjusted accurately only when the deflection coils themselves have been wound with such a precision that no coil asymmetries occur. Because in practice it is a very difficult task to wind the deflection coils with such a precision, solutions have been looked for so as to be able to nevertheless adjust the convergence without problems also when less accurately manufactured deflection coils are used.In this connection United States Patent Specification 3,810,053 discloses a deflection unit in which the magnetic ring can be moved horizontally or vertically with respect to the system of deflection coils. In this manner it is possible to compensate for coil asymmetries. The means disclosed in said United States Patent Specification for moving the magnetic ring, however, exhibit a number of drawbacks. Since the movement in a desired direction takes place only via a lead, the adjustment cannot take place entirely without play.Furthermore, a number of auxiliary rings are necessary having projecting lugs in which a screwthread is provided because the required screws cannot have their screwthread in the magnetic ring, and said auxiliary rings must be provided with cams and slots so as to ensure the guiding of the ring, while separate means are necessary to enclose the magnetic ring in the axial direction (the direction in which it may not move).
It is the object of the invention to provide a deflection unit in which coil asymmetries can be compensated for using a minimum of extra parts.
The invention provides a deflection unit of the type described in the opening paragraph in which the adjusting means is provided at the end of the magnetic ring which in use faces the screen of the cathode ray tube the magnetic ring and comprising a resilent member and a diametrically positioned adjustment means between which the magnetic ring is retained in position, said adjustment means having a moveable adjusting face inclined to the direction in which the magnetic ring is to be displaced, the adjusting face engaging with a parallely disposed face which has a fixed position with respect to the magnetic ring movement of the adjusting face effecting displacement of the magnetic ring in the said direction.
With such a deflection unit the adjusting means for moving the magnetic ring permits a movement in the desired direction without play. The adjustment means and the resilient member may serve as the means for retaining the magnetic ring in position in its axial direction so that the extra means of the known device may be omitted. For that purpose the resilient member preferably consists of an elongate resilient element which is secured in the frame inclined at an angle to the longitudinal axis of the deflection unit.
Although no extra means may be needed to retain the magnetic ring in position, it may be desirable for structural reasons to house the magnetic ring in an auxiliary ring so as to "enlarge" its diameter.
Since the magnetic ring surrounds the system of coils at a small distance its position can be adjusted along a given axis, for example the vertical axis, by the described adjusting means. Its position can preferably also be adjusted along the other axis (in this case the horizontal axis) so that an adjustment in two mutually perpendicular directions is provided.To this end the deflection unit may additionally comprises second adjusting means for displacing the magnetic ring relative to the deflection coils in a second direction perpendicular to the longitudinal axis of the deflection unit and to the first mentioned direction, the said second adjusting means also being provided at the end of the magnetic ring which in use faces the screen of the cathode ray tube and comprising a second resilient member and a second diametrically positioned second adjustment means between which the magnetic ring is also retained in position, said second adjustment means having a moveable adjusting face inclined to the second direction in which the magnetic ring is to be displaced, which adjusting face engages with a parallely disposed second face which has a fixed position with respect to the magnetic ring, movement of the second adjusting face effecting displacement of the magnetic ring in the said second direction.
Each of the resilient members and the adjusting faces preferably engage with a flat surface provided on the ring.
An advantage of this construction is that during adjustment the magnetic ring can be displaced in one of the directions without a movement in the other of the directions.
This is ensured by the adjusting means for displacing the ring in the said other direction retaining it in that direction.
A fine adjustment of the displacement is not caused directly by the pitch of a thread as the extent of the displacement depends upon the angle of inclination of the adjusting face.
The movement of the adjusting face can be realised in various ways. For example, the adjusting means may comprise a flat disk eccentrically rotatable about an axis perpendicular to the corresponding direction, the said disk having a conical surface which constitutes the adjusting face.
Due to its flat construction this arrangement has advantages if little space is available and if it is required for the adjusting means to be operatable from the gun side of the deflection unit. When there is sufficient space, however, there are advantages in the adjusting means being a screw having a conical head, the screw being journalled in the frame perpendicular to the direction in which the magnetic ring is to be displaced the conical surface of the head of the screw constituting the adjusting face.
The invention will now be described in greater detail, by way of example, with reference to the accompanying drawings in which: Figure 1 shows diagrammatically the construction of a deflection unit which is provided on the neck of a cathode ray tube, Figure 2 is a longitudinal sectional view of a deflection unit according to the invention Figure 3 is a cross-sectional view of the deflection unit shown in Figure 2, Figure 4 shows a detail of a preferred embodiment of the adjusting means of the deflection unit shown in Figure 2, Figure 5 shows a detail of an alternative embodiment of the adjusting means of the deflection unit shown in Figure 2, and Figure 6 is a diagrammatic elevation of the display screen 2 of the cathode ray tube shown in Figure 1.
Figure 1 shows an in-line colour display tube 1 having a display screen 2, a tube neck 3, and three electron guns 4 situated in one plane. A deflection unit 5 secured to the neck 3 of the tube comprises a rotationally symmetric magnetic ring 6, coils 7 for the horizontal deflection and coils 8 for the vertical deflection. The ring 6 surrounds the outer coil 8 of the system of coils with a small amount of play to permit a displacement of the ring 6 in the horizontal and/or the vertical direction.
Figure 2 shows that the ring 6 is mounted in a frame 9 at its display screen end. By turning a screw 11 which has a conical head and is journalled in a nut 18 parallel to the zdirection, the ring 6 can be moved in the ydirection against the pressure of a resilient member 10 (for example, a leaf spring or a spring of a synthetic material) which engages with a flat surface 12 of the ring 6.
The conical surface of the screw 11 constitutes an adjusting face which engages with a flattening 13 provided on the ring 6.
On one side the screw 11 is guided by the inner wall of a flange 19 of the frame 9.
Figure 3 shows that, in addition to the means 10 and 11 which retain the ring 6 in position in they-direction, means 14 and 15 are provided on the frane 9 which retain the ring 6 in the x-direction, Reference numeral 15 denotes a screw having a conical head which is journalled in a nut (not shown) parallel to the z-direction. By turning the screw 15 the conical surface of which cooperates with a flattening 17 of the ring 6, the ring 6 can be moved in the x-direction against the pressure of a resilient member 14 (for example a leaf spring or a spring of a synthetic resin) which cooperates with a flat surface 16 of the ring 6. When the ring 6 is displaced in the x-direction it is retained in the correct y-position by the resilient member 10 opnosed by the conical surface of the screw 11.When the ring is displaced in they-direction it is retained in the correct xposition by the resilient member 14 and the screw 15.
With reference to a detail of Figure 2, Figure 4 shows that the resilient member 10 may be inclined to the z-axis so that it acts as a means for retaining the ring 6 in position in the z-direction. Similarly, the resilient member 14 (Figure 3) may be inclined to the z-direction so that it acts as a means for retaining ring 6 in position in the z-direction. Resilent members 10 and 11 may be assembled in a desired position in slots 20 and 21, respectively, provided in the flange of the frame 9 (Figure 3).
Figure 5 shows the part of the ring 6 of Figure 1 with the flattenning 13. Instead of displacing the ring 6 by means of the conical screw 11 shown in Figure 2, it is alternatively possible within the scope of the invention to displace said ring by turning a flat disk having a conical surface around an eccentric axis 22 extending parallel to the x-direction. Because during adjustment this adjustment means is not moved by a screw action in the direction of axis 22 the foremost end of coil 8 may extend as far as, or even, beyond the adjustment means which would raise problems when using a conical screw as in Figure 2 as the adjustment means with its movement in the axial direction could foul such an extension.
In the manner as described above it is possible, for example, to place all the deflection units leaving the factory on a "standard" cathode ray tube and adjust for possible coil asymmetries, (if desired this adjustment may be carried out automatically via pins engaging in the screws 11 and 15). If so adjusted it will generally not be necessary for a customer who correctly mounts such a pre-adjusted deflection unit on a cathode ray tube to carry out this adjustment himself.
If necessitated by the shape of the coils 7 and 8 (saddle shaped coils are shown in Figure 1, but the invention is not restricted to the use of this type of coils), or if it is undesirable to provide the flattenings 12, 16 and the flat surfaces 13, 17 on the ring 6 itself, the ring 6 may be housed in an auxiliary ring (not shown). The auxiliary ring may then be provided with the required flattening and flat surfaces and, since the diameter of the magnetic ring is as it were "enlarged", the coils are no hindrance for the adjusting means.
The display screen shown in Figure 6 shows how upon energisation of the electron guns of a given cathode ray tube/deflection unit combination looking at the red traces (R) and the blue traces (B) do not coincide as a result of coil asymmetries, as is shown with reference to the positions on the screen indicated as B, C, D and E. In order to compensate for said coil asymmetries (which is called astigmatic symmetrizing), the magnetic ring of the deflection unit may be moved in the x and the y-directions.
In order to compensate for a line astigmatism 2 2 of 2.4 mm, the magnetic ring in a given case has to be moved along the x-axis over a distance of 1 mm., while in order to compensate for a frane astigmatism 2 2 of 3.8 mm, the magnetic ring had to be moved along the y-axis over a distance of 1 mm.
WHAT WE CLAIM IS: 1. A deflection unit for a cathode ray tube comprising a frame adapted to embrace portions of the cone and neck of a cathode ray tube, a system of coils consisting of a set of horizontal and a set of vertical deflection coils supported by the frame, and a softmagnetic ring surrounding the active part of the system of coils, the frame comprising adjusting means for displacing the magnetic ring relative to the deflection coils in a direction perpendicular to the longitudinal axis of the deflection unit, and means for retaining the magnetic ring in position in its axial direction, said adjusting means being provided at the end of the magnetic ring which in use faces the screen of the cathode ray tube and comprising a resilient member and a diametrically positioned adjustment means between which the magnetic ring is retained in position, said adjustment means having a moveable adjusting face inclined to the direction in which the magnetic ring is
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (10)

  1. **WARNING** start of CLMS field may overlap end of DESC **.
    are provided on the frane 9 which retain the ring 6 in the x-direction, Reference numeral
    15 denotes a screw having a conical head which is journalled in a nut (not shown) parallel to the z-direction. By turning the screw 15 the conical surface of which cooperates with a flattening 17 of the ring 6, the ring 6 can be moved in the x-direction against the pressure of a resilient member
    14 (for example a leaf spring or a spring of a synthetic resin) which cooperates with a flat surface 16 of the ring 6. When the ring 6 is displaced in the x-direction it is retained in the correct y-position by the resilient member 10 opnosed by the conical surface of the screw 11.When the ring is displaced in they-direction it is retained in the correct xposition by the resilient member 14 and the screw 15.
    With reference to a detail of Figure 2, Figure 4 shows that the resilient member 10 may be inclined to the z-axis so that it acts as a means for retaining the ring 6 in position in the z-direction. Similarly, the resilient member 14 (Figure 3) may be inclined to the z-direction so that it acts as a means for retaining ring 6 in position in the z-direction. Resilent members 10 and 11 may be assembled in a desired position in slots 20 and 21, respectively, provided in the flange of the frame 9 (Figure 3).
    Figure 5 shows the part of the ring 6 of Figure 1 with the flattenning 13. Instead of displacing the ring 6 by means of the conical screw 11 shown in Figure 2, it is alternatively possible within the scope of the invention to displace said ring by turning a flat disk having a conical surface around an eccentric axis 22 extending parallel to the x-direction. Because during adjustment this adjustment means is not moved by a screw action in the direction of axis 22 the foremost end of coil 8 may extend as far as, or even, beyond the adjustment means which would raise problems when using a conical screw as in Figure 2 as the adjustment means with its movement in the axial direction could foul such an extension.
    In the manner as described above it is possible, for example, to place all the deflection units leaving the factory on a "standard" cathode ray tube and adjust for possible coil asymmetries, (if desired this adjustment may be carried out automatically via pins engaging in the screws 11 and 15). If so adjusted it will generally not be necessary for a customer who correctly mounts such a pre-adjusted deflection unit on a cathode ray tube to carry out this adjustment himself.
    If necessitated by the shape of the coils 7 and 8 (saddle shaped coils are shown in Figure 1, but the invention is not restricted to the use of this type of coils), or if it is undesirable to provide the flattenings 12, 16 and the flat surfaces 13, 17 on the ring 6 itself, the ring 6 may be housed in an auxiliary ring (not shown). The auxiliary ring may then be provided with the required flattening and flat surfaces and, since the diameter of the magnetic ring is as it were "enlarged", the coils are no hindrance for the adjusting means.
    The display screen shown in Figure 6 shows how upon energisation of the electron guns of a given cathode ray tube/deflection unit combination looking at the red traces (R) and the blue traces (B) do not coincide as a result of coil asymmetries, as is shown with reference to the positions on the screen indicated as B, C, D and E. In order to compensate for said coil asymmetries (which is called astigmatic symmetrizing), the magnetic ring of the deflection unit may be moved in the x and the y-directions.
    In order to compensate for a line astigmatism 2
    2 of 2.4 mm, the magnetic ring in a given case has to be moved along the x-axis over a distance of 1 mm., while in order to compensate for a frane astigmatism 2
    2 of 3.8 mm, the magnetic ring had to be moved along the y-axis over a distance of 1 mm.
    WHAT WE CLAIM IS: 1. A deflection unit for a cathode ray tube comprising a frame adapted to embrace portions of the cone and neck of a cathode ray tube, a system of coils consisting of a set of horizontal and a set of vertical deflection coils supported by the frame, and a softmagnetic ring surrounding the active part of the system of coils, the frame comprising adjusting means for displacing the magnetic ring relative to the deflection coils in a direction perpendicular to the longitudinal axis of the deflection unit, and means for retaining the magnetic ring in position in its axial direction, said adjusting means being provided at the end of the magnetic ring which in use faces the screen of the cathode ray tube and comprising a resilient member and a diametrically positioned adjustment means between which the magnetic ring is retained in position, said adjustment means having a moveable adjusting face inclined to the direction in which the magnetic ring is
    to be displaced, the adjusting face engaging with a parallely disposed face which has a fixed position with respect to the magnetic ring, movement of the adjusting face effecting displacement of the magnetic ring in the said direction.
  2. 2. A deflection unit as claimed in Claim 1 comprising second adjusting means for displacing the magnetic ring relative to the deflection coils in a second direction perpendicular to the longitudinal axis of the deflection unit and to the first mentioned direction, the said second adjusting means also being provided at the end of the magnetic ring which in use faces the screen of the cathode ray tube and comprising a second resilient member and a second diametrically positioned second adjustment means between which the magnetic ring is also retained in position, said second adjustment means having a second moveable adjusting face inclined to the second direction in which the magnetic ring is to be displaced, which adjusting face engages with a parallely disposed second face which has a fixed position with respect to the magnetic ring, movement of the second adjusting face effecting displacement of the magnetic ring in the said second direction.
  3. 3. A deflection unit as claimed in Claim 1 or 2, in which the first mentioned or each resilient member and the adjusting face of the first mentioned or each adjustment means engage corresponding flat surfaces provided on the magnetic ring.
  4. 4. A deflection unit as claimed in Claim 1, 2 or 3, in which the first mentioned or each adjustment means comprises a flat disk eccentrically rotatable about an axis perpendicular to the said direction or directions, the said disk having a conical surface which constitutes the adjusting face.
  5. 5. A deflection unit as claimed in Claim 1, 2 or 3, in which the first mentioned or each adjusting means comprises a screw having a conical head, the screw being journalled in the frame perpendicular to the said direction or directions, the conical surface of the head of the screw constituting the adjusting face.
  6. 6. A deflection unit as claimed in Claim 5, in which the or each conical headed screw is guided by flange provided on the frame.
  7. 7. A deflection unit as claimed in any of the preceding Claims, in that the magnetic ring is housed in an auxiliary ring.
  8. 8. A deflection unit as claimed in any of the preceding claims in which the or each resilient member consists of an elongate resilient element secured in the frame and inclined to the longitudinal axis of said deflection unit, the or each inclined resilient member and associated adjustment means forming the means for retaining the magnetic ring in its axial direction.
  9. 9. A deflection unit for a cathode ray tube substantially as herein described with reference to the accompanying drawings.
  10. 10. A cathode ray tube having a deflection unit as claimed in any of the Claims.
GB14733/78A 1977-04-18 1978-04-14 Television deflection unit Expired GB1597741A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
NL7704184A NL7704184A (en) 1977-04-18 1977-04-18 DEFLECTION UNIT FOR A CATHOD RAY TUBE AND CATHOD RAY TUBE EQUIPPED WITH SUCH A DEVICE.

Publications (1)

Publication Number Publication Date
GB1597741A true GB1597741A (en) 1981-09-09

Family

ID=19828375

Family Applications (1)

Application Number Title Priority Date Filing Date
GB14733/78A Expired GB1597741A (en) 1977-04-18 1978-04-14 Television deflection unit

Country Status (9)

Country Link
JP (1) JPS596468B2 (en)
AU (1) AU3516378A (en)
DE (1) DE2815020C2 (en)
ES (1) ES468861A1 (en)
FR (1) FR2388398A1 (en)
GB (1) GB1597741A (en)
IT (1) IT1108064B (en)
NL (1) NL7704184A (en)
SE (1) SE7804223L (en)

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3810053A (en) * 1972-08-28 1974-05-07 Pemcor Inc Deflection yoke having relatively adjustable core and coils
NL7508613A (en) * 1975-07-18 1977-01-20 Philips Nv ADJUSTABLE DEVICE COIL SET FOR A COLOR TELEVISION PICTURE TUBE.

Also Published As

Publication number Publication date
FR2388398B3 (en) 1980-12-12
IT7867848A0 (en) 1978-04-14
JPS596468B2 (en) 1984-02-10
JPS53129520A (en) 1978-11-11
SE7804223L (en) 1978-10-19
DE2815020C2 (en) 1985-09-19
DE2815020A1 (en) 1978-10-26
ES468861A1 (en) 1979-08-16
NL7704184A (en) 1978-10-20
IT1108064B (en) 1985-12-02
FR2388398A1 (en) 1978-11-17
AU3516378A (en) 1979-10-25

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Legal Events

Date Code Title Description
PS Patent sealed [section 19, patents act 1949]
PCNP Patent ceased through non-payment of renewal fee