EP0668604B1 - Verfahren zur Herstellung einer Kathode eines Mikrospitzen-Fluoreszenzbildschirms und daraus resultierendes Produkt - Google Patents

Verfahren zur Herstellung einer Kathode eines Mikrospitzen-Fluoreszenzbildschirms und daraus resultierendes Produkt Download PDF

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Publication number
EP0668604B1
EP0668604B1 EP95410012A EP95410012A EP0668604B1 EP 0668604 B1 EP0668604 B1 EP 0668604B1 EP 95410012 A EP95410012 A EP 95410012A EP 95410012 A EP95410012 A EP 95410012A EP 0668604 B1 EP0668604 B1 EP 0668604B1
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EP
European Patent Office
Prior art keywords
layer
grid
cathode
microtips
resistive
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
EP95410012A
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English (en)
French (fr)
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EP0668604A1 (de
Inventor
Jean-Frédéric Clerc
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.)
Pixel International SA
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Pixel International SA
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Publication date
Application filed by Pixel International SA filed Critical Pixel International SA
Publication of EP0668604A1 publication Critical patent/EP0668604A1/de
Application granted granted Critical
Publication of EP0668604B1 publication Critical patent/EP0668604B1/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
    • H01J9/00—Apparatus or processes specially adapted for the manufacture, installation, removal, maintenance of electric discharge tubes, discharge lamps, or parts thereof; Recovery of material from discharge tubes or lamps
    • H01J9/02—Manufacture of electrodes or electrode systems
    • H01J9/022—Manufacture of electrodes or electrode systems of cold cathodes
    • H01J9/025—Manufacture of electrodes or electrode systems of cold cathodes of field emission cathodes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J31/00—Cathode ray tubes; Electron beam tubes
    • H01J31/08—Cathode ray tubes; Electron beam tubes having a screen on or from which an image or pattern is formed, picked up, converted, or stored
    • H01J31/10—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes
    • H01J31/12—Image or pattern display tubes, i.e. having electrical input and optical output; Flying-spot tubes for scanning purposes with luminescent screen
    • H01J31/123—Flat display tubes
    • H01J31/125—Flat display tubes provided with control means permitting the electron beam to reach selected parts of the screen, e.g. digital selection
    • H01J31/127—Flat display tubes provided with control means permitting the electron beam to reach selected parts of the screen, e.g. digital selection using large area or array sources, i.e. essentially a source for each pixel group
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
    • H01J2201/00—Electrodes common to discharge tubes
    • H01J2201/30—Cold cathodes
    • H01J2201/319—Circuit elements associated with the emitters by direct integration

Definitions

  • the subject of the present invention is a method for manufacturing a cathode fluorescent screen with microtips, as well as a fluorescent screen with microtips.
  • It relates to the industrial sector of flat display screens with row-column matrix addressing, and more particularly of display screens using microtip technology, that is to say made up of a vacuum tube formed by two plates of thin glass, the back plate, or cathode plate, comprising a matrix array of field effect emitters deposited by thin film techniques, and the front plate, or anode plate, covered on its internal face with a transparent conductive layer carrying phosphors.
  • each light point (pixel) of the anode is associated with an emissive surface located opposite and made up of a large number of microtips.
  • This emissive surface is defined by the intersection of a line (grid) and a column (cathode conductor) of the matrix (eg EP-A-0 234 989).
  • the cathode of a conventional microtip screen consists essentially of four layers deposited successively on a glass or silicon substrate, then etched, namely: a conductive layer playing the role of cathode "column conductors", a resistive layer generally made of silicon intended to limit the value of the emission current, an insulating layer and finally a second conductive layer constituting the "line conductors" of the grid. After depositing these layers, holes are formed in the grid and the insulating layer in which the microtips are then deposited.
  • the production of the constituent layers of the cathode requires at least four, and preferably five, photolithographic masking and etching operations, namely an etching of the cathode columns, an etching of the holes, an etching grid lines, etching of cathode contacts, and preferably a partial etching of the resistive layer between the cathode columns to avoid leaks and couplings between columns.
  • the images formed by a microtip screen are observed through the anode plate and it is the side of the phosphors opposite to that which receives the electrons which is seen, that is to say the least bright.
  • An object of the present invention is to simplify the manufacture of the cathode of microtip fluorescent screens by reducing the number of masking levels to three instead of five.
  • Another object of the present invention is to make said cathode transparent to obtain an improvement in light efficiency by allowing the observation of the luminescent material from the side where the electrons strike it, through the cathode.
  • the column conductors can consist of fine metallic meshes.
  • microtip fluorescent screen cathode The method of manufacturing a microtip fluorescent screen cathode according to the invention is defined in claim 1.
  • the fluorescent microtip screen according to the invention is defined in claim 7.
  • intersection of a row and a column defines an image point 7 or pixel ( Figure 1).
  • a column conductor 2 consists of an openwork or mesh strip.
  • Each grid line is made of meshes consisting of square conductive elements 6 linked together by fine conductive bridges 8 (for the sake of simplification in FIG. 2, only the longitudinal bridges have been represented; it is clear that there are also two transverse bridges for each square as shown in Figure 8).
  • the microtips 4 are located in the grid squares and not in the conductive bridges.
  • Each image point 7 is made up of several squares (four in FIG. 1 but much more in practice). Each square carries several microtips (four in the figure but often 16 in a real device).
  • the respective dimensions of the meshes of the column conductors 2 and of the squares constituting the grid 6 are determined so as to provide empty areas 9 between said squares and each column conductor. We can thus observe the anode phosphors through the cathode plate.
  • the access resistance to the microtips is therefore essentially controlled by the geometry of the bars as well as by the resistivity of the resistive layer.
  • This access resistance must be high enough to standardize and limit the emission current of the tips while introducing only a few volts of voltage drop.
  • a screen was produced according to the invention.
  • the resistive layer was made of amorphous silicon offering a resistance of 100 megohms per square, four bars allowed access to each square mesh of 25 micrometers side; the bars had a length to width ratio of 2.
  • the emission measured was 500 mA per dm 2 . Results of the same order of magnitude can be obtained with neighboring values.
  • Figure 2 also shows that the electrical continuity along a grid line, from mesh to mesh is ensured by four conductive bridges 8 covering four insulating bars and four resistive bars 10. Since the mask which was used to engrave them is unique , the conductive bars ensuring the continuity of the grid lines and the resistive bars ensuring the access of the cathode current to the microtips have the same width and length.
  • the same shape of the bars must allow the passage of a large current in the grid lines and only allow the passage of a negligible leakage current from one column to another.
  • This leakage current is inversely proportional to the resistance of the resistive layer 3 while the current of polarization of the grids is inversely proportional to the resistance of the upper conductive layer.
  • a resistance per square of 100 megohms is enough to guarantee the emission rate required for a screen.
  • the resistance of the gate metal in comparison is very low: 1 ohm per square in the case of the device produced, thanks to a niobium grid 6 400 nm thick. The resistance ratio in the device was therefore 10 8 .

Landscapes

  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Cold Cathode And The Manufacture (AREA)
  • Electrodes For Cathode-Ray Tubes (AREA)

Claims (9)

  1. Verfahren zur Herstellung einer Kathode eines Mikrospitzen-Fluoreszenzbildschirms, welche eine Trägerplatte (1) umfaßt, die mit Kathodenleitern in maschenförmigen Spalten (2), mit einer Mikrospitzen (4) tragenden Widerstandsschicht (3), mit einer Isolierschicht (5) und mit einer Gitterleiterschicht in Zeilen (6) überzogen ist,
    dadurch gekennzeichnet, daß die drei oberen Schichten Gitterschicht (6), Isolierschicht (5) und Widerstandsschicht (3) gemeinsam gemäß einem einzigen durchbrochenen Muster geätzt werden, das gleichzeitig die Gitterzeilen und die Zugangswiderstände zu den Mikrospitzen (4) über die genannte Widerstandsschicht definiert.
  2. Verfahren nach Anspruch 1,
    dadurch gekennzeichnet, daß es lediglich drei Ätzstufen umfaßt.
  3. Verfahren nach Anspruch 2,
    dadurch gekennzeichnet, daß es die folgenden Stufen umfaßt:
    - Aufbringen einer Kathoden-Metallschicht (11),
    - Ätzen von Leitern in Form maschenförmiger Spalten (2) in der genannten Metallschicht mittels einer ersten Maske,
    - Aufbringen einer Widerstandsschicht (3), einer Isolierschicht (5) und einer Gitter-Leiterschicht (6),
    - Ätzen der Löcher (12) für die Erzeugung von Mikrospitzen (4) mittels einer zweiten Maske,
    - Aufbringen der Mikrospitzen (4),
    - gleichzeitige Ätzung der Gitterschicht (6), der Isolierschicht (5) und der Widerstandsschicht (3) in durchbrochenen Zeilen mittels einer dritten und letzten Maske, welche gleichzeitig die Freilegung der äußeren Kontaktierungsbereiche der Spalten und Zeilen gewährleistet.
  4. Verfahren nach einem der vorhergehenden Ansprüche,
    dadurch gekennzeichnet, daß das Muster der Gitter-Leiterschicht (6), der Isolierschicht (5) und der Widerstandsschicht (3) aus Rechtecken besteht, die untereinander durch dünne Brücken verbunden sind und so Maschen bilden, wobei jeder Bildpunkt bzw. jedes Pixel (7) aus mehreren Maschen besteht.
  5. Verfahren nach Anspruch 4,
    dadurch gekennzeichnet, daß der Strompfad des durch die Widerstandsschicht (3) fließenden Stroms von dem einen Spaltenleiter (2) bildenden feinen Maschenwerk bis zur Basis einer Mikrospitze (4) durch vier jeweils eine Masche einrahmende Widerstandsbalken (10) definiert wird, die gleichzeitig mit den Leiterbrücken (8) des Gitters (6) gebildet werden.
  6. Verfahren nach Anspruch 4,
    dadurch gekennzeichnet, daß die jeweiligen Abmessungen der Maschen der Spaltenleiter (2) und der das Gitter (6) bildenden Rechtecke so bestimmt werden, daß nach der dritten Ätzung leere Zonen (9) zwischen den genannten Rechtecken und dem genannten Maschenwerk verbleiben, welche die Beobachtung von auf einer Anodenplatte gebildeten Leuchtstoffen durch das Kathodengebilde hindurch gestatten.
  7. Mikrospitzen-Fluoreszenzbildschirm mit einer Kathodenplatte, welche eine durchsichtige Trägerplatte (1) umfaßt, die mit Kathodenleitern in maschenförmigen Spalten (2), mit einer Mikrospitzen (4) tragenden Widerstandsschicht (3), mit einer Isolierschicht (5) sowie mit einer Gitter-Leiterschicht in Zeilen (6) überzogen ist,
    dadurch gekennzeichnet, daß die drei Schichten Gitterschicht (6), Isolierschicht (5) und Widerstandsschicht (3) gemäß einem einzigen Muster geätzt sind, welches derart bestimmte Elemente bildet, daß zwischen diesen Elementen und dem Maschenwerk der Spalten Leerzonen (9) verbleiben, welche die Beobachtung von Leuchtstoffen einer Anodenplatte durch die Kathodenplatte hindurch gestatten.
  8. Mikrospitzen-Fluoreszenzbildschirm nach Anspruch 7,
    dadurch gekennzeichnet, daß die das Muster des Gitters (6) und der Isolierschicht (5) und Widerstandsschicht (3) bildenden Elemente aus die Mikrospitzen (4) aufnehmenden Rechtecken bestehen, die untereinander durch feine Leiterbrücken (8) für das Gitter (6) und durch Widerstands- oder Isolierbalken zur Bildung von Maschen verbunden sind, wobei jeweils jeder Bildpunkt oder jedes Pixel (7) aus mehreren Maschen besteht und jede Masche mehrere Mikrospitzen (4) trägt.
  9. Mikrospitzen-Fluoreszenzbildschirm nach Anspruch 8,
    dadurch gekennzeichnet, daß das Gitter (6) aus Niob oder Aluminium mit einer Dicke von etwa 400 nm besteht und daß die Widerstandsschicht (3) aus amorphem Silizium hergestellt ist, das einen Widerstand in der Größenordnung von 100 MOhm je Rechteck bietet, wobei vier Widerstandsbalken (10) mit einem Längen/Breiten-Verhältnis von 2 jeweils den Zutritt zu jeder Rechteckmasche gestatten, die jeweils Seiten von etwa 25 µm besitzen.
EP95410012A 1994-02-22 1995-02-20 Verfahren zur Herstellung einer Kathode eines Mikrospitzen-Fluoreszenzbildschirms und daraus resultierendes Produkt Expired - Lifetime EP0668604B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9402291 1994-02-22
FR9402291A FR2716571B1 (fr) 1994-02-22 1994-02-22 Procédé de fabrication de cathode d'écran fluorescent à micropointes et produit obtenu par ce procédé .

Publications (2)

Publication Number Publication Date
EP0668604A1 EP0668604A1 (de) 1995-08-23
EP0668604B1 true EP0668604B1 (de) 1997-06-25

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EP95410012A Expired - Lifetime EP0668604B1 (de) 1994-02-22 1995-02-20 Verfahren zur Herstellung einer Kathode eines Mikrospitzen-Fluoreszenzbildschirms und daraus resultierendes Produkt

Country Status (5)

Country Link
US (1) US5574333A (de)
EP (1) EP0668604B1 (de)
JP (1) JP3616418B2 (de)
DE (1) DE69500372T2 (de)
FR (1) FR2716571B1 (de)

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA2154245A1 (en) * 1993-01-19 1994-08-04 Leonid Danielovich Karpov Field-emission device
US5952987A (en) * 1996-01-18 1999-09-14 Micron Technology, Inc. Method and apparatus for improved gray scale control in field emission displays
FR2756969B1 (fr) * 1996-12-06 1999-01-08 Commissariat Energie Atomique Ecran d'affichage comprenant une source d'electrons a micropointes, observable a travers le support des micropointes, et procede de fabrication de cette source
US6144144A (en) * 1997-10-31 2000-11-07 Candescent Technologies Corporation Patterned resistor suitable for electron-emitting device
US6414428B1 (en) 1998-07-07 2002-07-02 Candescent Technologies Corporation Flat-panel display with intensity control to reduce light-centroid shifting
FR2783633B1 (fr) * 1998-09-18 2003-02-07 Pixtech Sa Cathode a micropointes a faible degazage
US6879097B2 (en) * 2001-09-28 2005-04-12 Candescent Technologies Corporation Flat-panel display containing electron-emissive regions of non-uniform spacing or/and multi-part lateral configuration
JP3892769B2 (ja) * 2002-07-08 2007-03-14 株式会社 日立ディスプレイズ 表示装置

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2593953B1 (fr) * 1986-01-24 1988-04-29 Commissariat Energie Atomique Procede de fabrication d'un dispositif de visualisation par cathodoluminescence excitee par emission de champ
NL9100122A (nl) * 1991-01-25 1992-08-17 Philips Nv Weergeefinrichting.
US5186670A (en) * 1992-03-02 1993-02-16 Micron Technology, Inc. Method to form self-aligned gate structures and focus rings
US5259799A (en) * 1992-03-02 1993-11-09 Micron Technology, Inc. Method to form self-aligned gate structures and focus rings
KR0129678B1 (en) * 1992-05-22 1998-04-06 Futaba Denshi Kogyo Kk Fluorescent display device

Also Published As

Publication number Publication date
FR2716571B1 (fr) 1996-05-03
JPH0850852A (ja) 1996-02-20
DE69500372D1 (de) 1997-07-31
US5574333A (en) 1996-11-12
FR2716571A1 (fr) 1995-08-25
DE69500372T2 (de) 1997-10-09
JP3616418B2 (ja) 2005-02-02
EP0668604A1 (de) 1995-08-23

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