EP0877407A1 - Anode eines flachen Bildschirms - Google Patents

Anode eines flachen Bildschirms Download PDF

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Publication number
EP0877407A1
EP0877407A1 EP98410045A EP98410045A EP0877407A1 EP 0877407 A1 EP0877407 A1 EP 0877407A1 EP 98410045 A EP98410045 A EP 98410045A EP 98410045 A EP98410045 A EP 98410045A EP 0877407 A1 EP0877407 A1 EP 0877407A1
Authority
EP
European Patent Office
Prior art keywords
anode
strips
bands
focusing
insulation
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.)
Pending
Application number
EP98410045A
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English (en)
French (fr)
Inventor
Axel Jäger
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.)
Pixtech SA
Original Assignee
Pixtech SA
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 Pixtech SA filed Critical Pixtech SA
Publication of EP0877407A1 publication Critical patent/EP0877407A1/de
Pending legal-status Critical Current

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    • 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
    • H01J29/08—Electrodes intimately associated with a screen on or from which an image or pattern is formed, picked-up, converted or stored, e.g. backing-plates for storage tubes or collecting secondary electrons
    • H01J29/085—Anode plates, e.g. for screens of flat panel displays

Definitions

  • the present invention relates to flat screens of display, and more particularly so-called cathodoluminescence screens, whose anode carries luminescent elements, separated from each other by insulating zones, and susceptible to be excited by electronic bombardment.
  • This bombing electronics requires the luminescent elements to be polarized and can come from microtips, low-lying layers potential for extraction or thermionic source.
  • Figure 1 shows the structure of a flat screen microtip color.
  • Such a microtip screen essentially consists a cathode 1 with microtips 2 and a grid 3 provided with holes 4 corresponding to the locations of the microtips 2.
  • the cathode 1 is placed opposite a cathodoluminescent anode 5 including a glass substrate 6 constitutes the screen surface.
  • Cathode 1 is organized in columns and is made up, on a glass substrate 10, cathode conductors organized in mesh from a conductive layer.
  • the microtips 2 are made on a resistive layer 11 deposited on the cathode conductors and are arranged inside meshes defined by the cathode conductors.
  • Figure 1 partially represents the interior of a mesh and the conductors cathode do not appear in this figure.
  • Cathode 1 is associated with grid 3 organized in lines. The intersection a row of grid 3 and a column of cathode 1 defines a pixel.
  • This device uses the electric field which is created between the cathode 1 and the grid 3 so that electrons are extracted from the microtips 2. These electrons are then attracted by phosphor elements 7 from the anode 5 if these are suitably polarized.
  • the anode 5 is provided with alternating bands of phosphor elements 7r, 7g, 7b each corresponding to a color (Red, Green, Blue). The strips are parallel to the columns of the cathode and are separated from each other by an insulator 8, generally silicon oxide (SiO 2 ).
  • the phosphor elements 7 are deposited on electrodes 9, made up of corresponding strips of a transparent conductive layer such as indium tin oxide (ITO).
  • ITO indium tin oxide
  • the sets of red, green and blue bands are alternately polarized with respect to the cathode 1, so that electrons extracted from the microtips 2 of a pixel of the cathode / grid are alternately directed towards the phosphor elements 7 opposite of each of the colors.
  • the rows of grid 3 are sequentially polarized at a potential on the order of 80 volts, while that the bands of phosphor elements (for example 7g in Figure 1) to be excited are biased under a voltage of the order of 400 volts via the ITO strip on which these phosphor elements are deposited.
  • Groups of ITO, carrying the other bands of phosphor elements (for example example 7r and 7b in figure 1), are at a low or zero potential.
  • the columns of cathode 1 are brought to respective potentials between a maximum emission potential and a no emission potential (for example 0 and 0 respectively 30 volts). We thus fix the brightness of a color component of each of the pixels in a line.
  • the choice of the values of the polarization potentials is linked to the characteristics of the phosphor elements 7 and microtips 2. Conventionally, below a difference of potential of 50 volts between the cathode and the grid, there is no electronic emission, and the maximum emission used corresponds at a potential difference of 80 volts.
  • a disadvantage of conventional screens is that they suffer a short lifespan, that is to say after relatively short operating time (around a hundred hours), the screen brightness decreases considerably and we even sometimes see destructive phenomena appear due to the formation of arcs between the cathode and the anode of the screen.
  • drift colored In practice, this means that at least one of the strips of phosphor material adjacent to the polarized strips begins to exhibit luminescence.
  • a first known technique to avoid this phenomenon of parasitic illumination consists in separating, by intervals of short times, the polarizations of the anode bands between two successive color subframes, and to apply a pulse of negative voltage on the strip which has just been polarized before positively bias the next anode strip to be excited.
  • a second known technique consists in depositing, on the isolation bands separating the phosphor bands, a conductive layer polarized at a negative or zero potential. Such a technique is described, for example, in document EP-A-0 635 865. The role of the conductive layer is then to prevent the emission of secondary electrons by the insulating layer of SiO 2 , and the creation of 'a positive charge zone between two bands of phosphor elements.
  • a drawback of this technique is that, in order not to harm the insulation between the anode strips, the insulation strips must be thick (of the order of 50 ⁇ m) so that the phosphor elements deposited (on a thickness of the order of 10 ⁇ m) between these strips are buried with respect to the conductive layer.
  • Another drawback is that the implementation of this technique lengthens the manufacturing time. Indeed, to be precise, the etching of the SiO 2 coating must be carried out by plasma, which is particularly long for such a thickness.
  • the thickness of the strips insulation must be chosen according to the resistivity of the phosphor elements while this resistivity may be different from one color to another.
  • the phosphor elements are generally deposited by screen printing.
  • the alignment of the screen printing mask with the etching pattern is, in practice, imperfect, so that phosphor elements often protrude slightly from the holes in the SiO 2 layer. In such a case, the insulation is no longer respected, because these overflows take place on the conductive layer.
  • the present invention aims to propose a new solution to the above screen life issues and color drift, which overcomes the disadvantages of the solutions known.
  • the invention aims, in particular, to propose a new solution to the problem of stray lighting linked to switching of the anode strips.
  • the present invention also aims to provide a solution compatible with conventional manufacturing processes of the screen and which does not require an additional step in the manufacturing process of the anode.
  • the present invention provides a flat screen display anode of the type comprising at least two sets of alternating parallel strips of conductors anode coated with phosphor elements, separated one from the other others by isolation bands and polarizable at different potentials depending on the phosphor elements to excite, and focusing conductive strips, aligned and substantially centered with the insulation bands, the bands focusing conductors having widths less than those of the isolation bands.
  • the focusing bands are polarized at a negative potential or zero.
  • the thickness of the insulation strips is between 1 and 5 ⁇ m.
  • the focusing strips are deposited on the isolation strips.
  • the width of the focusing conductive strips represents between 20 and 60% of the width of the insulation strips.
  • the focusing bands are buried in the isolation bands.
  • the difference between a focusing band and a neighboring band of anode conductor is chosen to support a difference of determined potential between these two neighboring bands, the width focusing conductive strips preferably representing 20 to 90% of the difference between two neighboring strips of conductors anode.
  • the focusing strips are made of the same material as the anode conductor strips.
  • the present invention also relates to a method of realization of a flat screen display anode in which the mask for defining the anode conductor strips defines also the pattern of the focusing conductive strips.
  • the present invention also relates to a flat screen display comprising a microtip cathode and a anode consisting of at least two sets of alternating strips phosphor elements and provided with focusing strips.
  • Figure 2 shows, partially and in section, a anode according to a first embodiment of the present invention.
  • the anode 5 ' is produced on a substrate 6, by glass temple, and is provided with alternating bands of phosphor elements 7r, 7g, 7b each corresponding to a color (Red, Green, Blue).
  • the strips are separated from each other by an insulator 8, generally silicon oxide (SiO 2 ).
  • the phosphor elements 7 are deposited on electrodes 9r, 9g, 9b, made up of corresponding strips of a transparent conductive layer such as indium tin oxide (ITO).
  • ITO indium tin oxide
  • additional conductive strips 19 are deposited on the insulating strips 8 separating two strips of phosphor elements neighbors.
  • the width of the strips additional 19 is less than the space separating two bands neighboring phosphor elements and therefore does not entirely cover the insulating strips 8.
  • the strips 19 are substantially centered on the insulating strips 8 and their width represents, for for example, 20 to 60% of the width of the strips 8.
  • the bands 19 are polarized at a potential at most equal to the minimum potential for polarization of the cathode to create an electric field repelling electrons emitted by microtips (not shown).
  • the bands 19 then have a focusing effect of the electrons emitted by the cathode to the bands 9 carrying the phosphor elements.
  • the energy of these electrons is extremely low (close to 0 electron volts) and these electrons are then unable to cause the emission of secondary electrons.
  • the parts 18 of insulation remaining on each side of each strip 19 provide insulation between these additional conductive strips and strips of phosphor elements without it necessary to increase the thickness of the insulating strips 8.
  • the insulating strips 8 have a thickness in accordance with the conventional precedents of realization a flat screen anode, for example, between 1 and 5 ⁇ m.
  • Another advantage compared to the known technique of EP-A-0635865 is that the misalignments between the deposition mask by screen printing of the phosphor elements by compared to the etching pattern of layer 8 is not a problem.
  • the possible overflows of the phosphor elements are here deposited on the insulating parts 18.
  • the thickness of the strips of phosphor elements is generally of the order of 10 ⁇ m.
  • Figures 3 and 4 show respectively in section and seen from below, a second embodiment of a color flat screen anode according to the present invention. To the Figure 4, the phosphor elements have not been shown.
  • a feature of this embodiment is provide between two neighboring conductive strips 9 carrying phosphor elements, an additional conductive strip 29, coated with insulating layer 8 separating the strips 9 together others.
  • these bands 29 are polarized at a potential at most equal to the minimum potential cathode polarization to create an electric field repelling the electrons emitted by the microtips.
  • the bands 29 are substantially centered between two neighboring bands 9 and preferably have a width comprised between 20 and 90% of the difference between two neighboring bands.
  • the focusing strips 29 can be wider than in the first embodiment.
  • the gap between a strip 29 and a band 9 is in fact only linked to the need for isolation between these tapes and need not guarantee isolation in the event of overflow of phosphor elements. Plus the focusing strips are large, the greater the focusing effect for a given potential.
  • the width strips 9 of anode conductors is of the order of 80 ⁇ m and the gap between two neighboring strips of anode conductors is on the order of 40 ⁇ m.
  • the bands 29 are made of the same material (eg ITO) that the bands 9 carrying the elements phosphors.
  • ITO the same material
  • An advantage of such an embodiment is that the production of an anode according to the invention does not require then no additional step compared to a traditional precedent for manufacturing a flat screen anode.
  • the interconnection of bands 29 to allow their polarization can then be carried out at the same time as the interconnections of the bands 9 are made by set of bands of the same color.
  • FIGS. 5A and 5B illustrate, in sectional views, taken respectively along lines A-A and B-B of FIG. 4, the interconnections of bands 9 and 29 at their ends.
  • the layer 8 is also open to create two pads 15 and 16 ( Figures 5A and 5B) connecting tracks 11 and 12.
  • the openings made at the rights of studs 13, 14 and 15, 16 are filled with a conductive material to transfer the contacts above layer 8.
  • An advantage of the present invention is that the structure planned is perfectly compatible with the steps of a process conventional manufacturing of a flat screen anode.
  • bands 19 or 29 are, for example, polarized at a potential loving between 0 and -200 volts.
  • An advantage of the present invention is that it eliminates the phenomenon of color drift observed on the screens classics.
  • Another advantage of the present invention is that it dramatically improves screen life by removing all risk of arcing between two strips of phosphor elements neighbors.
  • the invention also applies to a monochrome screen in which the phosphor elements of the anode are carried by anode electrodes organized in two sets alternating bands of phosphor elements of the same color.
  • the invention further improves the resolution of the screen which is already better than that of a screen whose anode is consisting of a plan of phosphor elements of the same color.
  • the present invention is capable of various variants and modifications which will appear to the man of art.
  • the polarization potential of the focus and width can be changed depending the type of screen and the polarization potentials of its constituents.

Landscapes

  • Cathode-Ray Tubes And Fluorescent Screens For Display (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
EP98410045A 1997-04-30 1998-04-29 Anode eines flachen Bildschirms Pending EP0877407A1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9705601A FR2762927A1 (fr) 1997-04-30 1997-04-30 Anode d'ecran plat de visualisation
FR9705601 1997-04-30

Publications (1)

Publication Number Publication Date
EP0877407A1 true EP0877407A1 (de) 1998-11-11

Family

ID=9506645

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98410045A Pending EP0877407A1 (de) 1997-04-30 1998-04-29 Anode eines flachen Bildschirms

Country Status (4)

Country Link
US (1) US6107733A (de)
EP (1) EP0877407A1 (de)
JP (1) JPH10321168A (de)
FR (1) FR2762927A1 (de)

Families Citing this family (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2800512B1 (fr) * 1999-10-28 2002-03-01 Pixtech Sa Ecran plat de visualisation a grille de protection
KR100542317B1 (ko) * 1999-12-24 2006-01-12 비오이 하이디스 테크놀로지 주식회사 전계 방출 표시 소자
KR100499120B1 (ko) * 2000-02-25 2005-07-04 삼성에스디아이 주식회사 카본 나노튜브를 이용한 3전극 전계 방출 표시소자
US6509696B2 (en) 2001-03-22 2003-01-21 Koninklijke Philips Electronics N.V. Method and system for driving a capacitively coupled fluorescent lamp
WO2007005014A1 (en) * 2005-06-30 2007-01-11 Thomson Licensing Segmented conductive coating for a luminescent display device

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6188432A (ja) * 1984-10-08 1986-05-06 Nec Corp ドツトマトリクス螢光表示管
EP0527240A1 (de) * 1991-03-01 1993-02-17 Seiko Epson Corporation Licht-projektionsapparat
EP0635865A1 (de) * 1993-07-21 1995-01-25 Sony Corporation Feldemissionsanzeigevorrichtung
DE4430061A1 (de) * 1994-08-22 1996-02-29 Noritake Co Ltd Fluoreszenz-Anzeigeröhre und Verfahren zu deren Herstellung
US5508584A (en) * 1994-12-27 1996-04-16 Industrial Technology Research Institute Flat panel display with focus mesh
US5606225A (en) * 1995-08-30 1997-02-25 Texas Instruments Incorporated Tetrode arrangement for color field emission flat panel display with barrier electrodes on the anode plate
WO1997008731A1 (en) * 1995-08-30 1997-03-06 Micron Technology, Inc. Field emission display device with focusing electrodes at the anode and method for constructing same

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5541478A (en) * 1994-03-04 1996-07-30 General Motors Corporation Active matrix vacuum fluorescent display using pixel isolation

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6188432A (ja) * 1984-10-08 1986-05-06 Nec Corp ドツトマトリクス螢光表示管
EP0527240A1 (de) * 1991-03-01 1993-02-17 Seiko Epson Corporation Licht-projektionsapparat
EP0635865A1 (de) * 1993-07-21 1995-01-25 Sony Corporation Feldemissionsanzeigevorrichtung
DE4430061A1 (de) * 1994-08-22 1996-02-29 Noritake Co Ltd Fluoreszenz-Anzeigeröhre und Verfahren zu deren Herstellung
US5508584A (en) * 1994-12-27 1996-04-16 Industrial Technology Research Institute Flat panel display with focus mesh
US5606225A (en) * 1995-08-30 1997-02-25 Texas Instruments Incorporated Tetrode arrangement for color field emission flat panel display with barrier electrodes on the anode plate
WO1997008731A1 (en) * 1995-08-30 1997-03-06 Micron Technology, Inc. Field emission display device with focusing electrodes at the anode and method for constructing same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN vol. 010, no. 263 (E - 435) 9 September 1986 (1986-09-09) *

Also Published As

Publication number Publication date
FR2762927A1 (fr) 1998-11-06
JPH10321168A (ja) 1998-12-04
US6107733A (en) 2000-08-22

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