EP0523322B1 - Kompensation des elektrischen Wechselfeldes an der Frontfläche von Kathodenstrahl-Bildröhren - Google Patents

Kompensation des elektrischen Wechselfeldes an der Frontfläche von Kathodenstrahl-Bildröhren Download PDF

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Publication number
EP0523322B1
EP0523322B1 EP92105012A EP92105012A EP0523322B1 EP 0523322 B1 EP0523322 B1 EP 0523322B1 EP 92105012 A EP92105012 A EP 92105012A EP 92105012 A EP92105012 A EP 92105012A EP 0523322 B1 EP0523322 B1 EP 0523322B1
Authority
EP
European Patent Office
Prior art keywords
voltage
picture tube
alternating
eht
cathode ray
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP92105012A
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0523322A1 (de
Inventor
Tor H. Moen
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.)
Tandberg Data AS
Original Assignee
Tandberg Data AS
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 Tandberg Data AS filed Critical Tandberg Data AS
Publication of EP0523322A1 publication Critical patent/EP0523322A1/de
Application granted granted Critical
Publication of EP0523322B1 publication Critical patent/EP0523322B1/de
Anticipated expiration legal-status Critical
Expired - Lifetime 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
    • H01J29/003—Arrangements for eliminating unwanted electromagnetic effects, e.g. demagnetisation arrangements, shielding coils
    • 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
    • H01J29/98—Circuit arrangements not adapted to a particular application of the tube and not otherwise provided for
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2229/00—Details of cathode ray tubes or electron beam tubes
    • H01J2229/0007—Elimination of unwanted or stray electromagnetic effects
    • H01J2229/0015—Preventing or cancelling fields leaving the enclosure

Definitions

  • the invention relates to a method for compensating the electrical alternating field on the front surface of cathode ray picture tubes, to which a high voltage with a portion of alternating voltage is supplied from a high voltage generator via an EHT high voltage connection, and to a device which is suitable for carrying out the method.
  • the internal alternating voltage of the picture tube which is responsible for the alternating electrical field.
  • the high-frequency components of this alternating voltage derive from the deflection frequency and its harmonics, in particular from the capacitive coupling with the rectifier for the high-voltage generator, hereinafter also referred to as the EHT generator, and from the capacitive coupling of the deflector coils; low-frequency components are caused by current fluctuations in the picture tube and the internal impedance in the EHT generator.
  • EP-A 0 498 589 describes a method and a device for reducing the alternating current field which is generated by a cathode ray tube in its vicinity.
  • a voltage with opposite polarity is applied to the anode of the cathode ray tube, which voltage is intended to compensate for the alternating current field.
  • EP-A 0 500 349 claims, among other things, the priority of 5.4.1991 (JP-73 236/91), which relates to FIGS. 1 to 8, 17, 18 and the corresponding parts of the description of this subsequently published document.
  • a method and a device for compensating the alternating electrical field on the front surface of cathode ray picture tubes is known, to which a high voltage with a portion of alternating voltage is supplied from an high voltage generator via an EHT high voltage connection, the AC voltage is sensed on the connecting line between the high-voltage generator and the EHT high-voltage connection, the AC voltage is amplified and inverted and the AC voltage thus inverted is applied to at least one external electrode provided in the immediate vicinity of the picture tube.
  • this circuit cannot be universally adapted to different electrodes, which are desirable for different cathode ray picture tubes for optimal compensation.
  • the object of the invention is therefore to provide a method which provides for a simple and effective compensation for the alternating electrical field on the front surface of cathode-ray picture tubes, and to provide a device with which the alternating electrical field can be compensated for and in particular for Carrying out the method is suitable.
  • Adequate compensation of the alternating electrical field can be achieved using this method or this device. This compensation is based on two effects, namely on the one hand that the internal AC voltage is reduced, and on the other hand that the electrical AC field generated by the remaining internal AC voltage is weakened by linear superposition with the field of the inverted AC voltage. Both effects together result in the desired compensation of the electrical alternating spring.
  • the gain of the inverting amplifier can be regulated, so that an optimal adaptation for the respective picture tube and external electrode is possible.
  • the external electrode or the external electrodes are expediently arranged outside the front surface of the cathode ray picture tube.
  • the external electrode (s) at least partially surrounds the front surface of the cathode ray picture tube. It can thus be achieved that the inverted alternating voltage produces an alternating field which also uniformly covers the front surface of the cathode ray picture tube, so that compensation is optimally possible.
  • the external electrode can be, for example, a ring electrode arranged outside the front surface of the cathode ray picture tube.
  • a separate component is required here, but this has the advantage that the formation of the inverting field can be influenced as desired.
  • a binding tape surrounding the cathode ray picture tube can also be used as the external electrode. This binding tape is present anyway, so that apart from the necessary feed lines, no further structural measures have to be taken on the cathode ray picture tube.
  • This Aquadag area usually consists of a colloidal graphite-water dispersion that has electrically conductive properties.
  • the compensation effect is mainly based on the superimposition of the field generated from the inverted AC voltage, and the proportion of the compensation which is attributable to the reduction in the internal electrical AC voltage is comparatively small. A large amplification of the AC voltage is therefore necessary in order to be able to generate the large electrical AC field required for the compensation.
  • a metallic sleeve, in particular a copper sleeve, surrounding the connecting line between the high-voltage generator and the EHT high-voltage connection is provided for sensing or removing the AC voltage.

Landscapes

  • Physics & Mathematics (AREA)
  • Electromagnetism (AREA)
  • Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)
  • Image-Pickup Tubes, Image-Amplification Tubes, And Storage Tubes (AREA)
  • Insulators (AREA)
EP92105012A 1991-07-16 1992-03-23 Kompensation des elektrischen Wechselfeldes an der Frontfläche von Kathodenstrahl-Bildröhren Expired - Lifetime EP0523322B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE4123565A DE4123565C1 (fi) 1991-07-16 1991-07-16
DE4123565 1991-07-16

Publications (2)

Publication Number Publication Date
EP0523322A1 EP0523322A1 (de) 1993-01-20
EP0523322B1 true EP0523322B1 (de) 1996-05-08

Family

ID=6436280

Family Applications (1)

Application Number Title Priority Date Filing Date
EP92105012A Expired - Lifetime EP0523322B1 (de) 1991-07-16 1992-03-23 Kompensation des elektrischen Wechselfeldes an der Frontfläche von Kathodenstrahl-Bildröhren

Country Status (6)

Country Link
US (1) US5243262A (fi)
EP (1) EP0523322B1 (fi)
JP (1) JPH05242821A (fi)
DE (2) DE4123565C1 (fi)
FI (1) FI922163A (fi)
NO (1) NO921821L (fi)

Families Citing this family (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE469456B (sv) * 1991-11-22 1993-07-05 Nokia Data Ab Foerfarande och anordning i en bildskaermsenhet foer att reducera elektriska vaexelfaelt i enhetens omgivning
JPH05244540A (ja) * 1991-12-14 1993-09-21 Sony Corp モニタ装置
DE4203828C2 (de) * 1992-02-10 1996-03-14 Siemens Nixdorf Inf Syst Bildschirmgerät
EP0568783B1 (en) * 1992-05-08 1998-09-23 Hitachi, Ltd. Cathode-ray tube apparatus and yoke
JP3180461B2 (ja) * 1992-09-09 2001-06-25 三菱電機株式会社 陰極線管装置
US5326978A (en) * 1992-12-17 1994-07-05 Intevac, Inc. Focused electron-bombarded detector
JP3277601B2 (ja) * 1993-03-31 2002-04-22 ソニー株式会社 Ｃｒｔディスプレイの漏洩電界相殺装置
GB2279216A (en) * 1993-06-15 1994-12-21 Ibm Cathode ray tube display with cancellation of electric field emission
GB2283646A (en) * 1993-10-30 1995-05-10 Ibm Reducing electric field emission from a CRT display
GB2293299A (en) * 1994-09-15 1996-03-20 Ibm Electric field emission reduction system
US5742128A (en) * 1995-02-02 1998-04-21 Orwin Associates, Inc. Apparatus for mitigating the effects of ambient magnetic fields on the operation of a CRT
JPH08227666A (ja) * 1995-02-20 1996-09-03 Matsushita Electric Ind Co Ltd Ｃｒｔディスプレイの漏洩電界低減装置
KR100190160B1 (ko) * 1995-10-27 1999-06-01 윤종용 디스플레이 기기의 전계 차폐 회로
US5818171A (en) * 1996-01-16 1998-10-06 Samsung Electronics Co., Ltd. Device for removing electric field of display
EP0785566A1 (en) * 1996-01-19 1997-07-23 Capetronic (Kaohsiung) Corp. Low varying electric field and radiation CRT
JPH09233355A (ja) * 1996-02-27 1997-09-05 Totoku Electric Co Ltd 不要電界の低減方法
MX9801232A (es) * 1997-02-15 1998-11-30 Lg Electronics Inc Circuito para eliminar ruido del campo electrico de radiacion en aparato de video.
FI119344B (fi) 1999-02-05 2008-10-15 It Per Lo Sviluppo Dell Elettr Menetelmä näyttöpäätteen ympäristöönsä aiheuttaman sähkökentän pienentämiseksi ja näyttöpääte

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0498589A2 (en) * 1991-02-07 1992-08-12 Nokia Display Products Oy A method and a coupling for decreasing the detrimental radiation caused by a cathode-ray tube
EP0500349A1 (en) * 1991-02-20 1992-08-26 Nanao Corporation Apparatus for suppressing field radiation from display device

Family Cites Families (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2163772A1 (de) * 1971-12-22 1973-07-05 Licentia Gmbh Schaltung zur verminderung der stoerstrahlung eines elektrischen leiters, insbesondere in einem fernsehempfaenger
US4207493A (en) * 1978-09-26 1980-06-10 Rca Corporation Cathode ray tube arc-over protection
JPS60218693A (ja) * 1984-04-13 1985-11-01 三菱電機株式会社 デイスプレイ装置
US4636911A (en) * 1984-11-30 1987-01-13 Rca Corporation Resonant degaussing for a video display system
SE459054C (sv) * 1986-03-07 1992-08-17 Philips Norden Ab Foerfarande foer reducering av magnetiskt laeckfaelt samt anordning foer genomfoerande av foerfarandet
US5151635A (en) * 1991-06-20 1992-09-29 Apple Computer, Inc. Apparatus and method for reducing the magnitude of time varying electric fields in CRT displays

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0498589A2 (en) * 1991-02-07 1992-08-12 Nokia Display Products Oy A method and a coupling for decreasing the detrimental radiation caused by a cathode-ray tube
EP0500349A1 (en) * 1991-02-20 1992-08-26 Nanao Corporation Apparatus for suppressing field radiation from display device

Also Published As

Publication number Publication date
EP0523322A1 (de) 1993-01-20
DE4123565C1 (fi) 1992-09-17
FI922163A (fi) 1993-01-17
DE59206213D1 (de) 1996-06-13
NO921821L (no) 1993-01-18
FI922163A0 (fi) 1992-05-13
US5243262A (en) 1993-09-07
NO921821D0 (no) 1992-05-08
JPH05242821A (ja) 1993-09-21

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