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
  • H01J11/20—Constructional details
  • H01J11/34—Vessels, containers or parts thereof, e.g. substrates
  • H01J11/36—Spacers, barriers, ribs, partitions or the like
• • 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
  • H01J9/24—Manufacture or joining of vessels, leading-in conductors or bases
  • H01J9/241—Manufacture or joining of vessels, leading-in conductors or bases the vessel being for a flat panel display
  • H01J9/242—Spacers between faceplate and backplate
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2211/00—Plasma display panels with alternate current induction of the discharge, e.g. AC-PDPs
  • H01J2211/20—Constructional details
  • H01J2211/34—Vessels, containers or parts thereof, e.g. substrates
  • H01J2211/36—Spacers, barriers, ribs, partitions or the like
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2211/00—Plasma display panels with alternate current induction of the discharge, e.g. AC-PDPs
  • H01J2211/20—Constructional details
  • H01J2211/34—Vessels, containers or parts thereof, e.g. substrates
  • H01J2211/36—Spacers, barriers, ribs, partitions or the like
  • H01J2211/366—Spacers, barriers, ribs, partitions or the like characterized by the material
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2217/00—Gas-filled discharge tubes
  • H01J2217/38—Cold-cathode tubes
  • H01J2217/49—Display panels, e.g. not making use of alternating current
  • H01J2217/492—Details
  • H01J2217/49207—Electrodes
  • H01J2217/4925—Mounting, supporting, spacing
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J2329/00—Electron emission display panels, e.g. field emission display panels
  • H01J2329/86—Vessels
  • H01J2329/8625—Spacing members
  • H01J2329/864—Spacing members characterised by the material

Definitions

• the invention relates to a plasma panel comprising two slabs forming between them a sealed space which is filled with discharge gas and which is partitioned into discharge cells delimited between these slabs by barriers forming a network.
• Such a panel is generally used for viewing images.
• the cells are generally divided into rows and columns.
• the barriers generally extend at least between the columns, sometimes also between the rows.
• the height of the barriers generally corresponds to the distance between the slabs, so that the barriers also serve as spacers.
• the sides of the barriers as well as one of the slabs are generally covered with phosphors capable of emitting visible light under the excitation of plasma discharges; by adapting the composition of the discharge gas, visible light can also be obtained directly, without phosphors.
• Document WO00 / 36625 describes a manufacturing process in which the barriers are molded in a polymer reverse pattern produced by photolithography; on page 8, lines 7 to 22, to make the barriers, the use of a molding paste comprising ceramic powders, glass frits, Portland cement or other metal oxide powders is described; the only example given at the end of the document describes precisely the use of a paste containing 40% by weight of cement (page 10, line 32) and paraffin oil as carrier fluid; after molding, the paraffin oil migrates into the photopolymerized material of the mold, which makes it possible to increase the densification of the mineral powder in the mold channels; a final heat treatment at 600 ° C.
• barrier materials clearly means that the consolidation of the barriers is obtained by sintering the cement powder or its decomposition products, not by a hydration action on the cement of the paste, especially at 600 ° C, the hydration products of the cement would be degraded if not broken down to the point of preventing a consolidation effect.
• An objective of the invention is to limit the number of heat treatments necessary to obtain sufficient consolidation of the barriers, and / or to lower the temperature, or even to avoid these heat treatments.
• the subject of the invention is a plasma panel comprising two slabs forming between them a sealed space which is filled with discharge gas and which is partitioned into discharge cells delimited between these slabs by barriers made of mineral material comprising a mineral binder and a mineral filler characterized in that said mineral binder is a hydraulic binder.
• the mineral binder is in the hydrated state and aggregates the mineral filler. To obtain this hydrated state, as illustrated below, it is therefore necessary to use water in the steps for manufacturing the plasma panel. It is the hydraulic binder in the hydrated state which is responsible for the consolidation of the barriers, which aggregates the grains of the mineral filler, unlike the barriers described in document WO00 / 36625 where the skilled person understands that the effect consolidation is obtained by sintering grains of cement powder (or ceramic powder) and where, given the high processing temperatures, the cement is no longer in the hydrated state.
• hydroaulic binder is understood to mean a material which, when it is formed in a block from a powder, can be hardened by a hydration reaction: thus, by mixing a mineral filler powder suitable for a hydraulic binder powder, by forming this powder mixture, for example by molding, the form obtained can be hardened after the hydration reaction.
• water is added to the powder mixture before pouring the liquid assembly into a mold; the addition of water constitutes what is generally called a mixing operation.
• the panel cells are generally divided into rows and columns.
• the barriers generally extend at least between the columns, sometimes also between the rows, in which case the barriers form a two-dimensional network.
• the height of the barriers generally corresponds to the distance between the slabs.
• the sides of the barriers as well as one of the slabs are generally covered with phosphors capable of emitting visible light under the excitation of plasma discharges; by adapting the composition of the discharge gas, visible light can also be obtained directly, without phosphors.
• Such a plasma panel generally comprises at least two arrays of electrodes arranged so that each cell is crossed by an electrode of each array.
• each slab supports at least one network of electrodes, so that the electrodes of a network carried by one slab cross the electrodes of a network carried by the other slab.
• At least one of the networks is covered by a dielectric layer, so as to provide a memory effect which facilitates the control of the panel.
• the hydraulic binder is a cement, for example based on aluminates or aluminosilicates.
• the proportion by weight of mineral filler in the mineral material of the barriers is greater than or equal to 50%.
• the mineral filler comprises more than 50% by mass of silica and / or alumina.
• the porosity of the barriers is greater than or equal to approximately 15%, preferably greater than 25%.
• FIG. 1 illustrates, in top view, three adjacent cells of a plasma panel according to an embodiment of the invention
• FIG. 2 illustrates a section of the panel of Figure 1, before assembly of the two tiles.
• Each of the cells thus delimited by these barriers has a rectangular shape with a dimension of 850 ⁇ m x 290 ⁇ m approximately.
• a paste is prepared intended to form, after application and drying on the slab, a raw barrier layer comprising 4% by weight of organic binder, 96% by weight of mineral barrier material, here based on cement:
• Portland type cement having a fairly fine particle size, for example an average grain diameter of the order of 1 ⁇ m; this cement is
• silica smoke lightly loaded with sub-micron silica powder, called "silica smoke"; this cement is considered to be a quick setting cement;
• a solution of 8 g of ethyl cellulose-based resin in 92 g of terpineol-based solvent is prepared; - 200 g of powder of mineral barrier material, here cement, are dispersed in 104 g of resin solution; homogenized by passing through a three-cylinder type mixer-attritor, so as to reduce the size of the powder aggregates below 7 ⁇ m; Terpineol is added if necessary to adjust the viscosity to around 50 Pa.s.
• the barrier paste is then applied to the slab, here by screen printing of six superimposed layers; each screen printing pass is followed by drying at 110 ° C .; a slab with a raw barrier layer, 150 ⁇ m thick, is then obtained.
• a denser screen fabric is used, for example at 90 threads / cm, and a less viscous paste, for example of the order of 20 Pa.s, to obtain surface sub-layers of smoothing on the surface of the barrier layer.
• the slab is coated with this paste with a roller (“roller-coater” in English) and the applied layer is dried in a continuous-running tunnel furnace provided with blowing and air extraction means; a single pass then makes it possible to apply the raw layer of thickness 150 ⁇ m.
• a protective mask is first applied to this layer having openings or patterns at the location of the cells to be dug by abrasion in the thickness of the raw layer; for this purpose:
• a photosensitive dry film with a thickness of about 40 ⁇ m is laminated on the green layer, at a suitable temperature and pressure;
• this film is exposed at the locations of the barriers, under a UV light beam and for a suitable duration;
• This film is then developed using a 0.2% solution of sodium carbonate at approximately 30 ° C, so as to remove the portions of film outside the locations of the barriers;
• a protective mask is thus obtained on the raw layer.
• an abrasive material is sprayed onto the mask using a nozzle with a linear slot of length 200 mm; as abrasive material, a metallic powder sold by the company FUJI, referenced S9 grade 1000, is used; during the so-called “sandblasting” projection operation, the sandblasting nozzle is kept approximately 10 cm from the slab, moves along the barriers to be formed at the speed of 50 mm / min. approximately, and the green slab being sanded moves in a direction perpendicular to that of the barriers at a speed of 70 mm / min. ; the blasting pressure is of the order of 0.04 MPa; the flow rate of metallic powder is approximately 2500 g / min.
• the mask On the top of the raw barriers thus formed, the mask is then removed by spraying with an aqueous solution at 35 ° C containing 1% soda (NaOH); after rinsing with water and drying under an air knife at 50 "C, a slab is obtained provided with a network of green barriers with a height of the order of 150 ⁇ m, width approximately 100 ⁇ m at the base and 70 ⁇ m These barriers comprise approximately 4% by weight of organic resin.
• a paste of sealing joint is then deposited on the periphery of the rear slab thus obtained; this sealing joint is here based on a fusible glass mashed in a cellulose solution giving a viscosity of the order of 100 Pa.s.
• a rear slab is then obtained, which has a network of barriers.
• a heat treatment is then carried out to remove the organic binder from the barriers and the phosphor layers: first temperature rise to 10 ° C / min. up to 350 ° C then first stage of 20 minutes at
• the barrier hardening treatment is then carried out, hardening which is obtained according to the invention by hydration reaction of the
• the slab obtained is passed through under a spray of water for 30 minutes, then the slab is dried with an air knife at room temperature , then with an air knife at 105 ° C.
• the slab is immersed in water for 6 hours.
• the slab is placed under steam pressure under suitable conditions of temperature and duration to obtain the hardening, that is to say the setting, of the cement.
• a rear panel is obtained which has a network of hardened barriers 3 coated with layers of phosphors 4R, 4G, 4B.
• the duration of this treatment can be advantageously shortened, in particular by reducing the times landing, or even increasing speeds
• the operation of removing organic binders and the operation of hardening the barriers are combined: first temperature rise to 10 ° C./min. up to 350 ° C then first 30 minute plateau at 350 ° C, passage into humid air obtained by bubbling air through a water tank maintained at 80 ° C, second temperature rise to 10 ° C / min. up to 480 ° C, then second stage from 30mi ⁇ to 480 ° C, and finally lowering in temperature to 10 ° C / min up to 350 ° C, then passage into dry air until the slab is completely cooled.
• a conventional front panel 5 is assembled on the rear panel according to the invention (see the two arrows designating the assembly in FIG.
• the front panel 5 conventionally comprises two arrays of coplanar electrodes X, Y.
• the plasma panel thus obtained shown in plan view in FIG. 1, comprises two slabs forming between them a sealed space which is filled with discharge gas and which is partitioned into discharge cells 6R, 6G, 6B delimited by the barriers 3, which are, according to the invention, hardened mineral material, that is to say aggregated, by a hydraulic binder which is in the hydrated state.
• the plasma panel thus obtained has good mechanical properties, in particular at the level of the barriers: no crushing of the barriers is observed.
• a mineral material of barriers based on Portland cement instead of using a mineral material of barriers based on Portland cement, it is possible to use a mineral material further comprising a mineral filler, such as alumina or silica,
• the hydration of the hydraulic binder therefore serves, according to the invention, to aggregate this mineral load.
• a mixture of 50% of the cement described above and 50% of silica powder is used as the barrier mineral material; as silica, we take for example a cristobalite type silica whose specific surface is less than 10 m 2 / g and whose average particle size is less than 10 ⁇ m, typically
• the barriers obtained also have good mechanical properties; thanks to the high porosity of the barriers, the pumping time required to evacuate the air contained between the slabs is greatly reduced.
• barriers made of mineral material based on hardened hydraulic binder, here the same Portland cement as before; 0 - a series of parallel, continuous barriers, 100 ⁇ m thick at the base and 70 ⁇ m at the top, to separate the columns, distributed in a step of 360 ⁇ m;
• the cells of the panel are rectangular.
• a barrier undercoat paste intended to replace the dielectric layer of the previous embodiment
• barrier paste it is an aqueous paste produced from a mixture of 50% cement and 50% “mixed” silica with 35% water:
• barrier undercoat paste it is an aqueous paste of a mixture of 40% cement, 20% alumina and 40% titanium oxide "spoiled" with 39% water:
• the mold consists of a removable upper part consisting of a click whose thickness corresponds to 20% of additional depth.
• the mold is coated with a release agent, then placed on a vibrating pot; we then fill the mold with the freshly prepared barrier paste and scrape off the excess.
• the filled mold is then placed in an atmosphere at 40 ° C to accelerate the setting reaction of the hydraulic binder, here the cement.
• the setting of the cement corresponds to a hydration reaction of the cement.
• step 1a a 30 ⁇ m thick undercoat of undercoat paste is deposited with the curtain on the slab and on the electrodes.
• the slab is then placed in a 50 ° C atmosphere to accelerate the setting reaction of the cement in the underlay.
• step 1-a After 1 hour of setting in the mold (step 1-a), the upper foil of the mold is removed so as to uncover the upper surface of the mold which will constitute the base of future barriers, and a very light spray of water is performed on this surface.
• the rear slab from Step 1-b is then applied to this surface, so as to apply the still malleable underlay against the base of future barriers.
• the assembly is then turned over so that gravity supports the mold and its barriers on the rear face; The whole is then placed in an atmosphere at 40 ° C. After 2 hours, it can be removed from the mold by removing the mold.
• the slab coated with its undercoat and its ba ⁇ Italian is stored for another 4 hours in an atmosphere saturated with humidity to perfect the setting reaction of the cement and thus obtain a hydraulic binder in the hydrated state which aggregates the mineral load of the barriers. and consolidates them. Then the slab is passed through a passage oven regulated at 115 ° C to remove the residual water.
• a network of hardened and consolidated barriers without sintering is thus obtained without heat treatment, based on a sub-layer which acts as a
• a suspension is prepared containing 70 g of phosphor powder dispersed in 130 g of a mixture of glycol ethers selected for their boiling temperature and their viscosity so as to obtain the temporary suspension of the phosphors without the use of resins. Colloidal suspensions of silica (or others) can however be used as thickener if necessary.
• a paste of sealing joint is then deposited on the periphery of the rear panel thus obtained; this sealing joint is here based on a glass with very low melting point in a paste similar to that of the phosphors giving a viscosity of the order of 80 Pa.s. Then dried at 120 ° C. V- Brief final heat treatment at low temperature:
• a conventional front panel is assembled on the rear panel according to the invention, the two panels are sealed by heat treatment suitable for obtaining at least partial fusion of the sealing glass, evacuates the air contained between the slabs
• the panel is filled with discharge gas under low pressure, and the pumping opening is sealed.
• the plasma panel thus obtained has good mechanical properties, in particular at the level of the barriers: no crushing of the barriers is observed.
• the method according to the second family of embodiments of the invention therefore makes it possible to produce the plasma panel slabs which carry the barriers without ever exceeding 250 ° C., which is very advantageous economically and for maintaining the barriers in a hydrated state according to the invention.
• a sealing joint based on sealing adhesive resistant to a temperature of 250 ° C., available on the market, is used, which makes it possible to seal the two slabs by heat treatment at only 250 °. VS ; in this case, thanks to the invention, none of the steps for manufacturing the panel does not exceed 250 ° C., which makes it easier to maintain the hydraulic binder of the hydrated state barriers, which advantageously limits any risk of degradation of the mechanical properties hydraulic barrier binder.
• other types of cement than Portland cement can be used without departing from the invention, in particular cements which, after setting, can withstand the temperatures of the treatments. thermal still necessary for the manufacture of the panel; other types of hydraulic binders than cement can be used without departing from the invention.
• the present invention applies to any type of plasma panel whose cells are compartmentalized by barriers; these plasma panels can be of the coplanar type, of the matrix type, or else of radio frequency or microwave excitation.

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• 2003
  • 2003-05-27 FR FR0306383A patent/FR2855644A1/fr active Pending
• 2004
  • 2004-05-24 JP JP2006530217A patent/JP4633726B2/ja not_active Expired - Fee Related
  • 2004-05-24 EP EP04734527A patent/EP1627407B1/de not_active Expired - Fee Related
  • 2004-05-24 CN CNB2004800141146A patent/CN100474488C/zh not_active Expired - Fee Related
  • 2004-05-24 DE DE602004005328T patent/DE602004005328T2/de active Active
  • 2004-05-24 US US10/558,009 patent/US7710033B2/en not_active Expired - Fee Related
  • 2004-05-24 WO PCT/EP2004/050905 patent/WO2004107381A2/fr active IP Right Grant
  • 2004-05-24 KR KR1020057022485A patent/KR101026462B1/ko not_active IP Right Cessation

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