Classifications

• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J11/00—Gas-filled discharge tubes with alternating current induction of the discharge, e.g. alternating current plasma display panels [AC-PDP]; Gas-filled discharge tubes without any main electrode inside the vessel; Gas-filled discharge tubes with at least one main electrode outside the vessel
  • H01J11/10—AC-PDPs with at least one main electrode being out of contact with the plasma
  • H01J11/12—AC-PDPs with at least one main electrode being out of contact with the plasma with main electrodes provided on both sides of the discharge space
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J11/00—Gas-filled discharge tubes with alternating current induction of the discharge, e.g. alternating current plasma display panels [AC-PDP]; Gas-filled discharge tubes without any main electrode inside the vessel; Gas-filled discharge tubes with at least one main electrode outside the vessel
  • H01J11/20—Constructional details
  • H01J11/34—Vessels, containers or parts thereof, e.g. substrates
  • H01J11/36—Spacers, barriers, ribs, partitions or the like

Definitions

• the invention relates to plasma panels, and more particularly to means making it possible to obtain a so-called "cell conditioning" effect.
• Plasma panels are image viewing screens of the" flat screen "type.
• PAPs There are two main families of PAPs: PAPs whose operation is of the continuous type, and those whose operation is of the alternative type. All these PAPs operate on the principle of a gas discharge accompanied by an emission of light. They generally comprise two insulating slabs, each carrying one or more networks of electrodes, and delimiting between them a space filled with gas. The slabs are joined together so that the electrode arrays are orthogonal. Each intersection of electrodes defines a cell to which a gas space corresponds.
• FIG. 1 shows by way of example, in a partial and simplified manner, a conventional structure of alternative color PAP.
• alternative PAP there are different types of alternative PAP, among which, for example, may be mentioned: those of the type using only two crossed electrodes to define and control a cell, as described in particular in a French patent published with the number 2,417,848; or those of the type called "coplanar structure" whose structure and operation are described for example in European patent document EP-A-0.135.382.
• Alternative PAPs have a common characteristic, which is to present an internal memory effect in operation, due to the fact that their electrodes are coated with a layer of dielectric material which isolates them from the gas, that is to say from the discharge. .
• the PAP is of the type with two crossed electrodes to define a cell. It comprises two substrates or panels 2, 3, one of which is a front plate 2, i.e. the slab which is on the side of an observer (not shown); this slab carries a first network of electrodes called "line electrodes" of which only 3 electrodes Y1, Y2, Y3 are shown.
• the line electrodes Y1 to Y3 are covered with a layer 5 of a dielectric material.
• the second panel 3 forms the rear panel, it is opposite to the observer and therefore it is it which preferably is provided with elements capable of preventing the transmission of light to the observer; it carries a second network of electrodes called “column electrodes” of which only 5 electrodes X1 to X5 are shown.
• the two tiles 2, 3 are made of the same material, generally glass. These two tiles 2, 3 are intended to be joined to each other, so that the array of row and column electrodes are orthogonal to each other.
• the column electrodes X1 to X5 are also covered with a layer 6 of dielectric material.
• the dielectric layer 6 is itself covered with layers forming strips 7, 8, 9 of phosphor materials, corresponding for example to the colors green, red and blue respectively. are arranged parallel to the column electrodes X1 to X5, above the latter from which they are separated by the dielectric layer 6.
• the rear slab 3 also comprises barriers 11, parallel to the phosphor strips 7, 8 , 9 and arranged between them.
• the PAP is formed by assembling the front and rear tiles 2, 3, an assembly which produces a matrix of cells C1 to Cn.
• the cells are then defined at the intersection each between a row electrode Y1 to Y3 and a column electrode X1 to X5.
• Each cell has a discharge zone, the cross section of which corresponds substantially to so-called “useful” surfaces formed by the facing surfaces of the two crossed electrodes.
• the discharge in the gas generates electric charges which, in the case of an 'alternative' PAP accumulates on the dielectrics 5, 6 with regard to the row and column electrodes; in the example shown, this is obtained at the level of the rear panel 3 using savings Ep1 to Epn, produced in the phosphor strips 7, 8, 9 substantially in line with the useful surfaces of the column electrodes X1 to X5.
• the intersections produced by the first row electrode Y1 with the column electrodes X1 to X5 define a row of cells, each cell being materialized by a saving: the first cell C1 is located at the level of the first saving Ep1 , the second cell C2 is located at the level of the second savings Ep2 and so on until the fifth savings Ep5 which materializes a fifth cell C5.
• the first, second and third savings Ep1, Ep2, Ep3 are located respectively in a green phosphor band 7, red 8 and blue 9, they thus correspond to monochrome cells of three different colors which together can constitute a trichrome cell.
• the quality of the discharges in each cell depends on the geometric and dimensional characteristics of the cells, and the overall quality of operation of the PAP requires that these characteristics be reproduced with a low dispersion for all the cells. of the PAP.
• One of these particularly important characteristics is the height of the gas space formed between the front and rear tiles 2, 3, when these are assembled to one another.
• the load-bearing barriers 11 therefore having the same height H1 as the space which separates the slabs 2, 3, they constitute relatively watertight partitions so that, in addition to their bracing function mentioned above, they perform another function so-called "confinement"
• This confinement function is well known, it consists notably on the one hand, of confining the discharge, ie of preventing its propagation towards neighboring unaddressed cells, and therefore of avoiding a crosstalk effect between cells; and on the other hand, to avoid that the ultraviolet radiation created by a discharge in a given cell excites the phosphors of adjacent cells and does not cause a lack of color saturation, this phenomenon being known as an effect
• the load-bearing barriers 11 being arranged so as to separate two phosphor strips 7, 8, 9 of different colors according to a so-called 'triad' structure, they perform these functions only between cells located along the same line electrode Y1 to Y3, as for cells C1 to C5.
• the present invention aims to allow in a PAP, the establishment of confinement and cell conditioning functions mentioned above, in a simple manner and without affecting the consistency of the spacing between the two tiles of the PAP. To this end, it proposes, in particular to decouple the function of bracing the slabs from that of confining the cells, so as to be able to measure the action of the means used for confinement.
• a plasma panel comprising two parallel slabs assembled to each other, at least two networks of electrodes defining cells, bracing means determining a distance between the slabs, means cell containment, is characterized in that the containment means are barriers whose height is perpendicular to the slabs, said height being less than the distance between the slabs.
• FIG. 2 shows a color plasma panel according to the invention.
• FIG. 2 shows in a simplified manner, by a view similar to that of FIG. 1, a plasma panel according to the invention, comprising a front panel 2a and a rear panel 3a.
• the PAP according to the invention is of a type similar to that of FIG. 1: in fact the front panel 2a is, in the example, identical to the front face 2 of FIG. 1 , the only differences with the prior art are shown at the rear face 3a, and relate to bracing means and confinement means.
• the rear panel 3a therefore comprises, in the same way as the rear panel 3 in FIG. 1, column electrodes X1 to X5 covered with a dielectric layer 6, itself covered by phosphor elements in the form of strips 7, 8 , 9 successive; as for the rear face 3 of FIG. 1, these bands 7, 8, 9 are parallel to the column electrodes X1 to X5 and include spares Ep1 to Epn which each materialize a cell C1 to Cn.
• the bracing means which determine the spacing distance between the two slabs 2a and 3a, are constituted by a network of balls or spheres of which only four balls S1, S2, S3, S4 are shown in FIG. 2.
• the bracing balls S1 to S4 are made of an electrically non-conductive material, glass or sapphire for example; it should be noted that such balls with diameters compatible with those required in this application (of the order of, for example, 150 micrometers), are fairly commonly used in industry.
• the confinement of cells C1 to Cn is obtained in a more limited manner than in the prior art, using confinement barriers B1, B2, ..., B5 having a height H2 less than the distance between the slabs, that is to say the diameter D1 of the balls S1 to S4.
• the confinement barriers B1 to B5 are arranged in the same way as the carrier barriers 11 of FIG. 1, that is to say parallel to the column electrodes X1 to X5 and so as to separate two contiguous phosphor strips 7, 8, 9 , these two phosphor strips having different colors.
• the barriers can thus fulfill confinement functions (as has been explained above), that is to say to slow down or even avoid the propagation of discharges from one cell to a neighboring cell, and constitute an isolation suitable for optically isolating a cell from the radiation emitted by neighboring cells of different colors.
• the barriers B1 to B5 must for this purpose have a height H2 sufficient to obtain this confinement, while providing between the top of these barriers B1 to B5 and the front slab 2a, sufficient space to allow an exchange between neighboring cells, exchange which allows the cell conditioning effect already explained.
• This useful space for obtaining the conditioning effect corresponds to a height H3, given by the difference between the diameter D1 of the balls S1 to S4 and the height H2 of the confinement barriers B1 to B5.
• the value H3 of the free space between the barriers B1 to B5 and the front panel 2a can vary according to technological conditions specific to the PAP, and it can be defined by experimentation. However, tests show that in a large number of cases, correct operation is obtained by giving the containment barriers B1 to B5, a height H2 of between approximately 65% and 85% of the diameter D1 of the balls S1 to S4.
• containment barriers B1 to B5 could also be adopted for another network of containment barrier (not shown), another network whose barriers extend perpendicularly to the barriers B1 to B5, so to form intertwined barriers therewith.
• a first and a second ball S1, S2 are placed respectively between the first and the second barriers B1, B2, and between the fourth and the fifth barriers B4, B5; these two balls S1, S2 are arranged along an axis 20 perpendicular to the confinement barriers B1 to B5, which axis is located substantially at equal distances between an edge 21 of the slab 3a and the savings Ep1 to Ep5.
• a third ball S3 other spacer balls can be arranged along for example a second axis 22, parallel to the first axis 20 and located between the savings Ep6 and Epn.
• the spacer balls can of course be arranged differently, the number and distribution of these balls on the surface of a slab 2a, 3a being determined for example as a function of the tolerance allowed on the value of the spacing D1 between the two tiles; the important thing is of course that the balls are placed between the cells and therefore not at the precise location of a cell so as not to harm the discharge.
• the confinement barriers B1 to B5 are integral with the slab which carries the phosphors (or the rear slab 3a in the example of FIG. 2), so as to provide a space H3 between their top and the other slab.
• This structure with confinement barriers of height less than the spacing distance of the slabs makes it possible to significantly reduce the evacuation time of the panel, which is appreciable during industrial manufacture.
• the confinement barriers B1 to B5 can be produced according to a conventional method, similar to that used for the carrying barriers 11 shown in FIG. 1: they are then made of an electrically non-conductive material, resistant to crushing, such as glass. , enamel, ceramic, etc. But, according to another characteristic of the invention, the confinement barriers B1 to B5 can be made of a "soft" material, that is to say a material which can be crushed under the effect of pressure exercised particularly by the balls S1 to S4; in this case, the confinement barriers B1 to B5 can be constituted for example by a friable deposit of alumina powder or else of silica.
• barriers B1 to B5 of the "furniture" type is that during the assembly of the front and rear tiles 2a, 3a, for each ball which possibly falls in front of a barrier, it can sink into the barrier without destroying it, as illustrated in FIG.
• the balls can be held in their position until the tiles are assembled, for example by a resulting bonding a heating of the slab; - either place the network of balls S1 to S4 on the same slab 3a as the confinement barriers B1 to B5: in this case, the balls can be more easily placed between these barriers.
• the "furniture" type barriers are crushed to allow one or more balls to penetrate, have the advantage of requiring less precision in positioning the network of balls, the network of barriers B1 to B5, and the relative positioning of the two slabs.

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• Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Plasma & Fusion (AREA)
• Gas-Filled Discharge Tubes (AREA)

Applications Claiming Priority (3)

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• 1997
  • 1997-06-10 FR FR9707181A patent/FR2764437B1/fr not_active Expired - Fee Related
• 1998
  • 1998-06-03 TW TW087108736A patent/TW432351B/zh not_active IP Right Cessation
  • 1998-06-05 JP JP50175199A patent/JP2002503384A/ja not_active Ceased
  • 1998-06-05 EP EP98929503A patent/EP0988643B1/de not_active Expired - Lifetime
  • 1998-06-05 WO PCT/FR1998/001153 patent/WO1998057347A1/fr active IP Right Grant
  • 1998-06-05 KR KR1019997011575A patent/KR100616324B1/ko not_active IP Right Cessation
  • 1998-06-05 DE DE69831330T patent/DE69831330D1/de not_active Expired - Lifetime
  • 1998-06-05 US US09/445,338 patent/US6400079B1/en not_active Expired - Fee Related

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