EP0446878B1 - Bildanzeigevorrichtung - Google Patents

Bildanzeigevorrichtung Download PDF

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Publication number
EP0446878B1
EP0446878B1 EP19910103789 EP91103789A EP0446878B1 EP 0446878 B1 EP0446878 B1 EP 0446878B1 EP 19910103789 EP19910103789 EP 19910103789 EP 91103789 A EP91103789 A EP 91103789A EP 0446878 B1 EP0446878 B1 EP 0446878B1
Authority
EP
European Patent Office
Prior art keywords
layer
image display
electron beams
aluminum
thickness
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
EP19910103789
Other languages
English (en)
French (fr)
Other versions
EP0446878A3 (en
EP0446878A2 (de
Inventor
Keiichi Otake
Noboru Aikawa
Atsunori Hosoki
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.)
Panasonic Holdings Corp
Original Assignee
Matsushita Electric Industrial Co Ltd
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
Priority claimed from JP6315890A external-priority patent/JPH03266339A/ja
Application filed by Matsushita Electric Industrial Co Ltd filed Critical Matsushita Electric Industrial Co Ltd
Publication of EP0446878A2 publication Critical patent/EP0446878A2/de
Publication of EP0446878A3 publication Critical patent/EP0446878A3/en
Application granted granted Critical
Publication of EP0446878B1 publication Critical patent/EP0446878B1/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
    • H01J29/02—Electrodes; Screens; Mounting, supporting, spacing or insulating thereof
    • H01J29/10—Screens on or from which an image or pattern is formed, picked up, converted or stored
    • H01J29/18—Luminescent screens
    • H01J29/28—Luminescent screens with protective, conductive or reflective layers

Definitions

  • the invention relates to a flat image display comprising a vacuum envelope having a face plate, a back cell and a plurality of vacuum cells having a potential gradient, a plurality of cathodes disposed within said vacuum envelope for radiating electron beams toward said face plate, control electrodes for controlling the electron beams radiated from said cathodes, a phosphor layer on said face plate and positioned to be irradiated by the electron beams and for emitting light when irradiated by the electron beams, and an aluminum back layer on the face of said phosphor layer towards said cathode for directing light emitted by said phosphor layer to the face of said face plate.
  • a flat image display having the same light emitting principle as that of the Braun tube is known from USA patents Nos. 4,451,846 and 4,449,148.
  • Such a flat image display uses electron beams from a plurality of linear thermal cathodes, controlled by a plurality of control electrodes, and colliding against a fluorescent screen. It can display letters, images and so on.
  • a back electrode 51 is adapted to direct into the front face direction electron beams 72 emitted from a plurality of linear thermal cathodes 52a through 52d.
  • An electron beam fetching electrode 53 fetches the electrons of the linear thermal cathode 52a through 52d.
  • Through holes 62 are provided in the electrode 53 to let the electron beams 72 pass through them.
  • a signal electrode 54 which is provided to apply video signals and is composed of a plurality of control electrodes 64.
  • the control electrodes 64 have through holes 63 therein to let the electron beams 72 pass through it.
  • a first focusing electrode 55 and a second focusing electrode 56 are provided to focus the electron beams 72 in the horizontal and vertical directions.
  • a horizontal deflection electrode 68 deflects the electron beams in the right, left directions of the picture face, and is composed of one set of comb type electrodes 57a and 57b.
  • the electrodes of the comb type electrodes 57a and 57b constitute a slot 67 to let the electron beams 72 pass through.
  • a vertical deflection electrode 71 is provided to deflect the electron beams 72 in the vertical direction of the picture face, and is composed of a set of comb type electrodes 58a and 58b.
  • the comb type electrodes 58a and 58b constitute a slot 70 between the electrodes to let the electrode beams 72 pass through it.
  • a face plate (surface glass cell) 60 has a screen 73 composed of a three color phosphor layers of red, green, blue, a black stripe layer provided between them, and a metal back layer provided behind them on the inner face thereof.
  • a metallic plate 61 made of a back cell, and the face plate 60 constitute a vacuum cell.
  • the rearward dispersed electrons generated by the electrons applied upon the metal back layer of the face plate 60 as the interior of the display element have a potential gradient, instead of equipotential like in conventional Braun tubes, and are applied again upon the face plate, thus resulting in lowering the contrast ratio.
  • Fig. 2 A, B are views showing the internal construction of a conventional Braun tube and of a conventional flat image display.
  • GB-A-2 120 840 discloses a cathode ray tube of the BRAUN type in which the electron beams are accelerated through a large potential difference immediately before impact with a fluorescent screen. This acceleration is provided in a large area channel plate electron multiplier which is disposed close to the face plate of the cathode ray tube. However, within the electron multiplier there occurs impact of electrons so that dispersed secondary electron beams are caused. Accordingly, no high accuracy in deflection can be obtained as is necessary in a flat thin type display device of the type as described in the present application.
  • a layer of material having an atomic number which is smaller than that of aluminum is provided on top of said aluminum back layer and facing said cathodes for reducing the generation of rearward dispersed electrons at the time of irradiation of said phospor layer by the electron beams, and the aluminum back layer having a thickness in relation to its supply voltage such that the transmission factor of the incident electrons becomes larger than 77 % and the transmission factor of the reflected and dispersed electrons becomes less than 16 %.
  • the layer of material having an atomic number which is smaller than that of aluminum preferably consists of a carbon layer.
  • Preferable embodiments defining the thickness of the aluminum back layer in relation to the supply voltage of the back layer are defined in the dependent claims.
  • a flat image display is provided where the generation of the rearward dispersed electrons is reduced by approximately half, the disturbing light emission of the fluorescent screen, except for the location where the electron beams become primarily incident, is also reduced by half, and the contrast ratio is improved twice.
  • reference numeral 1 is a back electrode equivalent to the back electrode 51 of Fig. 1
  • reference numeral 2 is a linear cathode equivalent to a linear cathode 52 of Fig.
  • reference numerals 3 through 7 are electrode blocks equivalent to a beam fetching electrode 53, a signal electrode 54, a focusing electrode 55, horizontal . vertical deflecting electrodes 57, 58 of Fig. 1
  • reference numeral 8 is a screen plate equivalent to a screen 73 of Fig. 1, the screen plate being composed of a glass plate 21, a phosphor 20 to be positioned on it, a metal back (aluminum layer) 101 provided on the phosphor 20, a carbon layer 104 provided on the metal back 101.
  • Reference numeral 102 shows electron beams to be generated from the linear cathode 2
  • reference numeral 103 is a rearward dispersed electrons (secondary electrons).
  • the rearward dispersed electrons 103 are 18% of the electron beams 102 incident in a case of aluminum (atomic number 13) normally used even in the metal back 101.
  • the rearward dispersed electrons 103 become 9% of the electron beams 102 incident in the case of carbon (atomic number 6). If a carbon layer 104 is formed on the metal back 101, the generation of the rearward dispersion electrons 103 can be prevented by half, and the contrast ratio is improved twice.
  • Fig. 4 is a structural model of a carbon layer forming method.
  • phosphor 20 and a metal back 101 are already formed on the internal face of a glass plate 21.
  • Carbon liquid 11 with powdered carbon being dissolved in a solvent such as water, alcohol or the like is put into a sprayer 12, is sprayed onto the metal back 101 of the glass plate 21 so as to provide the carbon layer 104. Thereafter, it is burned at approximately 450°C and the face plate is completed as a whole.
  • the thickness of the carbon layer 104 can be adjusted by the spraying time or the spraying amount of the sprayer 12. When the carbon layer 104 is too thick, the passing ratio of the electron beams is lowered, thus reducing the brilliance.
  • Fig. 6 is a structural model of another carbon layer forming method.
  • phosphor 20 and a metal back 101 are already formed on the internal face of a glass plate 21.
  • a sufficient amount of carbon powder 13 is prepared and a glass plate 21 is placed above it with the metal back 101 being directed downwards.
  • a high voltage of a high tension generator 14 connected with the metal back 101 is applied, and a carbon layer 104 is formed on the metal back 101 by the electric evaporation. Thereafter, it is burned at approximately 450°C and the face plate is be completed as a whole.
  • the carbon layer is formed by electric evaporation, a more uniform carbon layer may be obtained than by the spraying in the first method.
  • the high-tension voltage to be applied upon the metal back on the face is comparatively low (in a case 15KV or lower), the face where uneven brilliance is not caused may be formed.
  • the equal effect may be obtained if the normal temperature solid material which is smaller at the atomic number than aluminum is used.
  • Fig. 7 is a graph showing the relation of the electron incident energy to the energy transmission factor when the thickness of the metal back 101 is provided as a parameter.
  • the metal back 101 is 1000 ⁇ in thickness with an electric potential of 10KV being applied upon it in Fig. 3.
  • the electron beams 102 generated from the linear cathode 2 (potential OV) are accelerated by the potential gradient with respect to the metal back 101, and are applied upon the metal back with the incident energy of 10keV.
  • the target is aluminum
  • 18% of the incident electrons are dispersed as rearward dispersed electrons 103, and the energy of the rearward dispersed electrons 103 becomes approximately 6keV (approximately 60 % of the incident energies).
  • the secondary electrons dispersed rearwards rush into the metal back again with an energy of approximately 6keV by the above described potential gradient.
  • the energy transmission factor of the incident electrons (10keV) is 92%
  • the energy transmission factor of the rearward dispersion electrons (6keV) is 64%. While the brilliance is extremely high, the transmission factor of the rearward dispersed electrons is also high, and the contrast is deteriorated.
  • the energy transmission factors of the incident electrons and of the rearward dispersed electrons are respectively 77%, 16%.
  • the energy transmission factor (which is proportional to brilliance) of the incident electrons changes from 92% to 77% and the brilliance is also lowered somewhat.
  • the energy transmission factor (proportional to halation) of the rearward dispersed electrons is reduced as extremely low from 64% to 16%. Therefore, the brilliance is satisfactory and the contrast is also extremely good.
  • the thickness of the metal back 101 is increased extremely, the brilliance is also extremely lowered, so that a proper thickness is demanded.
  • the thickness is proper to be 2000 ⁇ or more and 3500 ⁇ or lower when the voltage of the metal back is 10KV. In the case of 9kV, it is proper to be 1500 ⁇ or more and 3000A or lower. In the case of 8KV, it is proper to be 1500 ⁇ or more and 2000 ⁇ or lower.
  • the halation may be considerably reduced within some brilliance reduction by the adjustment of the thickness.

Landscapes

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

Claims (5)

  1. Eine Flachbildanzeigeschaltung mit einer Flachbildanzeigevorrichtung und einer Schaltungsanordnung mit einer Spannungsquelle, wobei die Flachbildanzeigevorrichtung eine Vakuumhülle mit einer Frontplatte (8), einer rückwärtigen Zelle (1) und einer Mehrzahl von Vakuumzellen mit Potentialgefälle enthält;
    eine Mehrzahl von in der Vakuumhülle angeordneten Kathoden (2) zum Ausstrahlen von Elektronenstrahlen (102) in die Richtung der Frontplatte (8) enthält; Steuerelektroden (3 ...7) zum Steuern der von den Kathoden (2) ausgestrahlten Elektronenstrahlen (102) enthält;
    eine Phosphorschicht (20) auf der Frontplatte (8) enthält, die so angeordnet ist, daß sie von den Elektronenstrahlen (102) bestrahlt wird und die Licht emittiert, wenn sie von den Elektronenstrahlen bestrahlt wird; und
    eine rückwärtige Aluminiumschicht (101) auf der Fläche der Phosphorschicht (20) enthält, die zur Kathode (2) gerichtet ist, um von der Phosphorschicht (20) emittiertes Licht auf die Fläche der Frontplatte (8) zu richten,
    dadurch gekennzeichnet,
    daß die Bildanzeigevorrichtung eine gleichförmige Schicht (104) eines Materials auf der rückwärtigen Aluminiumschicht (101) und zu den Kathoden (2) gewandt enthält, dessen Atomzahl kleiner ist als die des Aluminiums, um die Erzeugung rückwärts streuender Elektronen während der Bestrahlung der Phophorschicht (20) durch die Elektronenstrahlen (102) zu verringern; daß die gleichförmige Schicht in einem elektrischen Verdampfungsverfahren abgelagert wird (Figur 6), daß die rückwärtige Aluminiumschicht (101) eine Dicke von 150 bis 350 nm aufweist, um den Transmissionsfaktor rückwärts streuender Elektronen (103), die während der Bestrahlung der Phosphorschicht (20) mit Elektronenstrahlen (101) erzeugt werden, auf nicht mehr als 30 % zu begrenzen; und
    daß die Spannungsquelle der rückwärtigen Schicht (101) eine Spannung von 8 kV bis 10 kV zuführt.
  2. Eine Bildanzeigevorrichtung nach Anspruch 1,
    bei der das Material der Schicht (104), dessen Atomzahl kleiner ist als die von Aluminium, Kohlenstoff ist.
  3. Eine Bildanzeigevorrichtung nach Anspruch 1 oder 2,
    bei der für eine Speisespannung der rückwärtigen Aluminiumschicht (101) von 10 kV eine Dicke von 200 nm bis 350 nm vorgesehen ist.
  4. Eine Bildanzeigevorrichtung nach Anspruch 1 oder 2,
    bei der für eine Speisespannung der rückwärtigen Aluminiumschicht (101) von 9 kV eine Dicke von 150 nm bis 300 nm vorgesehen ist.
  5. Eine Bildanzeigevorrichtung nach Anspruch 1 oder 2,
    bei der für eine Speisespannung der rückwärtigen Aluminiumschicht (101) von 8 kV eine Dicke von 150 nm bis 200 nm vorgesehen ist.
EP19910103789 1990-03-14 1991-03-13 Bildanzeigevorrichtung Expired - Lifetime EP0446878B1 (de)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
JP63158/90 1990-03-14
JP6315890A JPH03266339A (ja) 1990-03-14 1990-03-14 画像表示素子
JP79442/90 1990-03-28
JP7944290 1990-03-28

Publications (3)

Publication Number Publication Date
EP0446878A2 EP0446878A2 (de) 1991-09-18
EP0446878A3 EP0446878A3 (en) 1992-03-25
EP0446878B1 true EP0446878B1 (de) 1998-06-03

Family

ID=26404244

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19910103789 Expired - Lifetime EP0446878B1 (de) 1990-03-14 1991-03-13 Bildanzeigevorrichtung

Country Status (2)

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EP (1) EP0446878B1 (de)
DE (1) DE69129506T2 (de)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR960016719B1 (ko) * 1993-02-08 1996-12-20 마쯔시다덴기산교 가부시기가이샤 전자빔표시장치 및 제조방법
US20010038894A1 (en) * 2000-03-14 2001-11-08 Minoru Komada Gas barrier film

Family Cites Families (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3340421A (en) * 1963-07-31 1967-09-05 Sony Corp Cathode ray tube having metallic layer of non-uniform thickness
US3703401A (en) * 1970-12-28 1972-11-21 Rca Corp Method for preparing the viewing-screen structure of a cathode-ray tube
GB2120840A (en) * 1982-05-12 1983-12-07 Philips Electronic Associated Contrast improvement in vacuum image display devices

Also Published As

Publication number Publication date
EP0446878A3 (en) 1992-03-25
DE69129506T2 (de) 1998-10-01
EP0446878A2 (de) 1991-09-18
DE69129506D1 (de) 1998-07-09

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