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
• • 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
  • H01J29/86—Vessels; Containers; Vacuum locks
  • H01J29/861—Vessels or containers characterised by the form or the structure thereof
  • H01J29/862—Vessels or containers characterised by the form or the structure thereof of flat panel cathode ray tubes
• • H—ELECTRICITY
  • H01—ELECTRIC ELEMENTS
  • H01J—ELECTRIC DISCHARGE TUBES OR DISCHARGE LAMPS
  • H01J1/00—Details of electrodes, of magnetic control means, of screens, or of the mounting or spacing thereof, common to two or more basic types of discharge tubes or lamps
  • H01J1/02—Main electrodes
  • H01J1/30—Cold cathodes, e.g. field-emissive cathode

Definitions

• the invention relates to a glass frame, intended to keep two flat substrates at their periphery separate.
• the invention will be more particularly described with reference to frames used to maintain a space between two sheets of glass in the production of flat and hermetic glass envelopes such as screens field emission, and therefore to maintain a space of constant but limited thickness, generally less than a few millimeters at the periphery of the glass sheets.
• Such a configuration is widely sought for the production of screens for viewing.
• These can be field emission screens (FED) comprising cathodes made up of carbon microtips or nanotubes or screens of the flat cathode tube type (“Fiat CRT”).
• FED field emission screens
• Fiat CRT flat cathode tube type
• Such a configuration can also be sought for the production of vacuum glazing or flat lamps.
• the expression flat lamps should be understood to include lamps used in the manufacture of portable computers and lamps of larger dimensions for the production of advertising panels or partitions, for example of offices, whatever the technology of these lamps. Indeed, in a screen of the field emission type, a limited space and in which a vacuum is created, must be maintained between the two sheets of glass. It is therefore necessary to provide means at the periphery of the screen which make it possible to define and maintain this space and which, in addition, provide a seal for the volume thus formed by the sheets. of glass and these peripheral means.
• a technique currently used to produce this peripheral element consists, from a glass sheet having the desired thickness for said element, to produce a frame whose edges have a width of the order of a centimeter. For this, the central part of the glass sheet is cut and eliminated. It is then possible to associate the glass frame thus obtained with the two glass sheets constituting the faces of the screen by means of an enamel paste or sealing frit which ensures the sealing function. If this achievement is satisfactory from a technical point of view, it has various drawbacks in its implementation.
• the inventors have therefore given themselves the task of designing means which make it possible to define and maintain a space between two flat substrates, which contribute to the sealing of the volume delimited by said substrates and said means being at least equivalent in terms of technical results to the last solution presented and which advantageously do not have the drawbacks of the solutions previously mentioned; they must advantageously be achievable for all thicknesses corresponding to the applications described above and at lower costs than those mentioned above.
• the size of these means must be reduced compared to the last technique mentioned so as to optimize the viewing area of the finished product, for example a screen.
• This object was achieved according to the invention by a glass frame whose section has a substantially polygonal outline comprising at least one re-entrant angle.
• the frame will be able to play the role of peripheral spacer and help to seal the volume between, for example, two flat glass substrates forming a screen.
• the section which has a re-entrant angle will in particular allow, for reasons to which we will return later, to stiffen the frame with side widths less than those of the prior techniques.
• the polygonal section which comprises at least one re-entrant angle is not necessarily constant over the entire periphery.
• substantially polygonal contour it should be understood that the segments of the polygon can be replaced by curves.
• the frame has the shape of a parallelogram, and each of its sides has a constant section.
• the frame according to the invention consists of at least four profiled glass elements, which advantageously correspond to each of the sides of the frame.
• Such glass profiles can in particular be produced according to a technique such as that described in document EP-0 627 389 A.
• This document describes a process which consists in stretching a pitch rod or glass rod which has a section of substantially identical shape. to that which one wants to obtain with a homothetic report close.
• This primitive bar which has a sufficiently large size can for example be machined according to the desired section, with great precision.
• this primitive bar can be initially polished on its lateral faces. The stretching step is carried out with an increase in the temperature of the original rod to a temperature close to its softening temperature and the actual stretching can then be carried out in one or more steps.
• the stretched rod obtained after stretching the primitive bar has a cross section similar in shape to that of the primitive bar except for a homothetic ratio, which corresponds to the cross section of the sides of the desired frame. Furthermore, the rod has a polished appearance on its lateral faces due to the passage at high temperature which creates a "fire polish". This phenomenon can make it possible not to use a primitive bar polished on its lateral faces but having another aspect such as a “soft fine” appearance insofar as a polished appearance is desired.
• fire-polished the invention refers to a surface roughness ("RMS value") of less than 5 A by AFM (atomic force microscope) measurement on a swept surface of approximately 6 ⁇ m. This roughness is advantageously of the order of 2 ⁇ .
• the rods can then be brought together parallel to each other.
• these rods are collected in a cylinder, in particular made of glass, and are joined together using a binder such as a wax or glue.
• the set of rods is then cut to the desired length so that they form the sides of the desired frame; of course this operation must be carried out for each of the lengths of elements necessary for the production of the frame.
• all the sides can be smoothed and then optionally polished at both ends. It is thus possible to obtain polished profile elements on all their faces. In addition, if the cut is not not very precise, it is thus possible to correct the length of the elements during polishing.
• the elements are then separated from one another, in particular by melting the binder or by chemical dissolution.
• the frame elements are directly brought to the desired dimension one by one, by cutting the rods or rigid sections resulting from the stretching step.
• the elements according to the invention can also be produced according to an extrusion method or a pultrusion method.
• the first method consists in making the necessary preform before stretching according to extrusion techniques and in stretching said preform according to the technique described above.
• Pultrusion consists in drawing the preform directly out of an extruder. According to these techniques, it appears that it is unnecessary to polish the faces of the preform while retaining a satisfactory polished appearance of the faces of the spacers after drawing.
• a final variant for producing these profiled elements consists in obtaining them directly by extrusion without any subsequent drawing.
• the elements obtained according to these manufacturing methods are such that the vertices of the polygonal section are, due to the drawing process, rounded with a radius of curvature between 2 and 50 microns and preferably between 5 and 20 microns. These rounded tops make it possible in particular for certain applications to limit the risks of damage to the glass sheets and possibly of the layers deposited on their surfaces in the event of sliding, for example during the positioning of said elements.
• the pultrusion process also allows the elimination of an intermediate step and in particular of preform storage, a continuous supply of the extruder leading to continuous manufacture of the elements for a given section.
• two elements adjacent profiles have complementary shapes allowing interlocking. It is, for example, a tenon-mortise type nesting.
• a frame is made up of two profiled elements having a tenon and two profiled elements presenting a mortise which will join to form a frame.
• the angles of the frame according to the invention are at least partly formed by brackets associated with the profiled elements.
• brackets will give better rigidity to the frame, and in particular prevent any risk of deformation thereof.
• Such brackets can be made of any material but are preferably made of glass.
• Such brackets can in particular be produced according to the techniques described above for the manufacture of the profiled elements; it is indeed possible to produce these glass brackets using a preform stretching technique or alternatively using extrusion or pultrusion techniques. In all cases, the square corresponds to the section of either drawing or extrusion.
• the assembly of the profiled elements is done only by means of brackets, that is to say that the profiled elements do not associate directly with each other by interlocking.
• the glass composition constituting the profiled elements is chosen similar to that of the glass substrates forming the two flat surfaces intended to be joined by the frame.
• the glass composition of the profiled elements is chosen with a melting point lower than that of the other constituent parts of the product to be produced and preferably less than 500 ° C; it is thus possible to seal the frame to planar substrates by slight fusion of said frame.
• the frame then acts as a sealing joint.
• Such a composition can for example be chosen from the sealing frit compositions usually used in the glass industry.
• elements into this composition which will make it possible to raise its temperature without requiring heating of the entire product; these may for example be coloring elements which allow absorption of infrared or laser radiation. It may also be elements such as those described in French patent application FR 00/02936 which make the glass conductive electronic and therefore whose temperature can be high under the influence of microwave radiation.
• the choice of electronic conductive glass compositions as described in application FR 00/02936 can also make it possible to optimize the size of the viewing area of a screen for a given overall size; in fact, the choice of sufficiently high resistivity can make it possible to obtain leakage currents between anode and cathode such that the frame can be very close to the pixels forming the vision area.
• the choice of their composition is similar to that presented for the profiled elements.
• the choice made for the profiled elements may impose that to be made for the brackets; for example if the profiled elements are made from compositions with a low melting point to allow the frame to be sealed on flat substrates, it may be wise to make the same choice for the brackets.
• a preferred embodiment provides brackets made from a composition with a low melting point and preferably having a melting point of less than 500 ° C., whatever the composition of the profiled elements; such an embodiment will make it possible, during the fusion of the brackets, to guarantee sealing at the junction of two profiled elements, the molten glass of a bracket penetrating by capillary action into the contact zone of said two elements.
• the fusion of the brackets can be obtained either by a local supply of heat, or by heating the brackets under the influence of radiation when they are sensitive to them, or by conduction in contact with the profiled elements which can be heated under the influence of radiation when they are chosen sensitive to such radiation.
• the frame comprises at least one recess over at least part of the length of at least one side.
• the first object of such a configuration may be to insert the brackets so that they are incorporated into the profiles.
• the recess (s) provided on the frame may have other interests or allow the insertion of other elements and in particular independent of the constitution of the frame; This is for example in the case of one or more recesses oriented towards the inside of the frame, elements involved in the operation of the product; in the case for example of products whose proper functioning requires a high level of vacuum, such as for example FED or Fiat CRT screens, it is necessary to provide within the screen "getters", which make it possible to maintain a high vacuum level throughout the lifetime of the screen, typically 10 years. According to the invention, it is possible to introduce these "getters" into the recesses provided in the frame. This is possible whatever their mode of presentation, in agglomerated powder, in pills, in threads, in the form of flat blades, etc.
• such an embodiment according to the invention will allow further optimize the viewing area of the screen since the "getters" are positioned in the frame and therefore does not cause any additional bulk.
• a final advantage of such an embodiment is that the "getters" can be distributed over the entire periphery in a homogeneous manner, which improves their efficiency.
• the external recesses in addition to the possibility of installing the brackets, can allow to receive other functional elements involved either in the production of the frame or in the production of the product such as a screen. It may for example be mechanical means which will allow for example by strapping to stiffen the frame formed by the profiled elements, in particular when the latter are not associated by means of brackets.
• the external recess is used to embed metal tools at the corners of the frame, these tools having a geometry adapted to serve both as staples and as elements ensuring the alignment of the lower glass sheets and higher at the time of sealing.
• a tool consisting of two heating forks encloses the elements of the frame and will act during the sealing cycle in the manner of a soldering iron. It is also possible to insert into these recesses materials sensitive to infrared, laser or microwave radiation, always to cause a rise in temperature; note that to insert such materials, the recesses can be provided inside or outside the frame.
• the invention also provides, according to an advantageous variant, in particular when it becomes useful to insert different elements in the constitutive frame or not thereof, to combine the presence of recesses on the internal area and on the external area of the frame.
• the glass frames thus described according to the invention can be used as a peripheral spacer between two glass sheets in the production of flat and hermetic glass envelopes such as the production of a display type screen, for example an emission screen field with cathodes made of carbon microtips or nanotubes or a screen of the flat cathode-ray tube type (Fiat
• the frame can be produced beforehand, in particular by assembling the various profiled elements when the frame thus formed has sufficient rigidity to be handled without risk. to deteriorate it.
• the production of the frame is made simultaneously with the production of the product such as a screen.
• the profiled glass elements will be assembled to each other either by assembling complementary shapes, such as tenon-mortise type shapes, or by the intervention of other elements and more particularly of brackets. glass, or by the combination of these two possibilities.
• the mechanical strength of the frame thus produced is obtained either simply due to the friction of the elements on each other, or by the intervention of other factors.
• the mechanical strength is obtained by inserting a complementary element such as a metal wire in a recess provided over the entire outer periphery of the frame, which allows the strapping of said frame.
• a fusion of at least part of the frame is carried out.
• the composition of the profiled elements, and that of the brackets when they are present are chosen with a low melting point, there is provision for a rise in the temperature of these elements which results in their fusion and their welding together and possibly the sealing on the two flat glass substrates when the entire product is produced at the same time.
• the rise in temperature can be obtained by placing the elements in a thermal enclosure or by any means known to those skilled in the art and in particular those mentioned above; the profiled elements can be produced with glass compositions sensitive to infrared or laser radiation or microwave, or provision is made to insert elements into internal or external recesses, said elements being sensitive to one of these radiation, or even a heating wire is provided inserted in an external recess to allow its electrical connection.
• the welding of the glass profile elements together can be obtained by the simple fusion of the brackets, in particular when the frame is produced before the manufacture of the screen.
• the means for obtaining the fusion of the brackets in such a case are of course the same as those set out above.
• the invention advantageously provides for using a sealing paste to fix the frame to the two flat substrates.
• the invention provides for a melting of the frame, the latter being chosen with a melting point lower than that of the flat substrates.
• the invention advantageously provides for local heating, limited to the area of the frame, according to one of the techniques already mentioned above.
• the use of local heating, limited to the area of the frame makes it possible in particular to avoid degradation of the various constituent elements, for example of a screen, deposited beforehand on the two glass sheets and generally sensitive to heat treatments.
• local heating is only a complementary heating to an overall heating of the whole product brought to a temperature which can be supported by all materials without risk of damage to them. this ; this variant can in particular make it possible to accelerate the rise in temperature and therefore productivity.
• the frame is entirely inserted between the two flat substrates to form the product such as a screen.
• only part of the frame is inserted between the two flat substrates; the frame then presents advantageously at least one part which is capable of coming to bear on the edge of at least one substrate.
• Such a configuration can be particularly advantageous for producing vacuum glazing which requires no electrical connection.
• such a configuration makes it possible to limit the shear stresses which appear at the level of the frame / flat substrate connection.
• the frame its height is advantageously provided with a dimension less than that of the space provided between the two flat substrates, when the connection between the frame and the substrate must be made by a sealing frit; this difference in size is preferably between 50 and 300 microns.
• connection is provided by fusion of the frame
• the latter is advantageously provided with a height greater than that desired in the end for the distance separating the two flat substrates; this difference is preferably between 20 and 300 microns.
• the height of these is advantageously between 0.3 and 12 mm.
• the height of the recesses is advantageously between 0.3 and 4.5 mm and preferably between 0.5 and 1.5 mm.
• the height of the recesses is advantageously between 1 and 12 mm and preferably between 1 and 4.5 mm.
• the thickness of the glass on either side of the recess is greater than 0.3 mm and preferably greater than 1 mm.
• Certain variant embodiments of the invention provide for making the frame as less visible as possible so as in particular to optimize the vision area, for example in the case of a screen.
• the frame produced according to the invention can, for the various reasons stated above and in particular due to either its rigidity or its simultaneous production with that of the product, be of a reduced size compared to known frames.
• the invention advantageously provides that at least the faces of the frame inserted between the flat substrates are diffusing.
• a diffusing effect can be linked to a frosted appearance which can for example be obtained by a chemical treatment of the profiled elements, such as an acid attack in a bath of ammonium fluoride and hydrochloric acid.
• FIGS. 1 and 2 which respectively represent:
• FIG. 1 a diagram of a device for producing profiled elements according to the invention
• FIG. 1 represents the diagram of an installation for the production, according to one of the variants proposed by the invention, of the profiled elements which will then be assembled to form a frame.
• the support 2 is itself fixed to a mechanical system.
• This mechanical system 2 which may for example be an endless screw, makes it possible to give a vertical downward movement to the original bar 1 along the axis 3 which can thus pass through a heating ring 4, of height approximately equal to 70 millimeters.
• This heating ring 4 is heated by the Joule effect at low voltage and is slightly oval in shape. This allows a better distribution of the heat around the primitive bar to the point that the temperature regulation is made more or less 0.1 degrees at 800 ° C.
• the heating ring 4 is surrounded by an insulating refractory 5. Placed under the heating ring at a distance of approximately 500 millimeters, a drawing device 6 allows the drawing of the pitch bar 1 so as to obtain a rod or fiberglass 7.
• the device 6 consists of two driving belts 8, 9 on which lateral pressure forces 10, 11 are exerted. These pressure forces 10, 11 promote stretching and are exerted by means not shown which are for example small hydraulic cylinders with adjustable pressure.
• the drawing speed is directly linked to the speed of rotation of the rollers 12 which each drive the two driving belts 8, 9.
• the driving belts 8, 9 are made of a material, for example silicone, making it possible to avoid slipping on the glass and therefore to obtain a regular stretching.
• FIGS. 2 correspond to profiles intended to form frames which will preferably be fully engaged between the two flat substrates forming the product such as a vision screen.
• Profiles whose cross section corresponds to Figure 2a will be able for example to be associated with each other to form a complete frame; according to an alternative embodiment, they are associated to form a peripheral recess 13 oriented towards the inside of the frame formed.
• the assembly is carried out so that the recess 13 is oriented towards the outside of the formed frame.
• the assembly of the profiled elements can be done by the insertion of glass brackets in the recesses 13.
• the brackets will therefore either be placed inside the frame or outside the frame.
• These glass brackets can for example be obtained according to the technique described in FIG. 1.
• the peripheral recess 13 can allow the insertion of other elements contributing or not contributing to the formation of the frame. It is for example a strapping wire, possibly heating, which contributes to the rigidity of the frame when the peripheral recess is external or for example of "getter", which maintains the desired vacuum, when the peripheral recess is inside.
• the section shown in FIG. 2b illustrates profiled elements similar to the previous one which, when they are associated with each other, for example using brackets, have the various advantages stated previously linked to the presence of interior and exterior recesses.
• Section 2c corresponds to a profiled element which can be associated with elements 2a or 2b according to the previously mentioned nesting principle of mortise-tenon.
• FIG. 2d illustrates a section of a profiled element more particularly suited to the production of a frame for flat lamps, this making it possible to increase the uniformity of lighting in the area close to the frame as soon as the angle ⁇ is between 30 and 60 °.
• FIGS. 3a, b, c and d correspond to profiled elements which have in common the fact of having an appendage 14 and which can be used according to the principle mentioned above which consists in introducing only between the planar substrates part of the frame formed by these profiled elements; the flat substrates then rest on the surfaces of appendix 14.
• Such profiled elements 3a, 3c may include bevel zones 15 to allow good positioning of the flat substrates which themselves advantageously have such complementary bevels.
• Such elements 3b, 3c may also have recesses 16,
• brackets are oriented towards the outside of the frame, allowing for example the presence of brackets.
• FIG. 4 illustrates an example of assembly of two profiled elements 18, 19 whose section is that of FIG. 2a and positioned so that the recess 13, represented by the dotted line 20, is oriented towards the interior of the frame which will be formed for example from four of these profiled elements.
• the recess 13 receives a square 21.
• the ends of the profiled elements have been provided with angles of 45 °.
• a frame thus produced is more particularly intended to be completely inserted between the peripheries of the two flat substrates.
• FIG. 5 illustrates the use of profiled elements such as those of FIGS. 3 according to which only the appendix 14 is inserted between the flat substrates 22 and 23.

Landscapes

• Joining Of Glass To Other Materials (AREA)
• Securing Of Glass Panes Or The Like (AREA)
• Vessels, Lead-In Wires, Accessory Apparatuses For Cathode-Ray Tubes (AREA)

Applications Claiming Priority (3)

Publications (1)

Family

ID=8849349

Family Applications (1)

Country Status (11)

Family Cites Families (16)

• 2000
  • 2000-04-17 FR FR0004949A patent/FR2807872B1/fr not_active Expired - Fee Related
• 2001
  • 2001-04-04 CZ CZ20023462A patent/CZ20023462A3/cs unknown
  • 2001-04-04 PL PL01357722A patent/PL357722A1/xx unknown
  • 2001-04-04 EP EP01921417A patent/EP1275131A1/de not_active Withdrawn
  • 2001-04-04 JP JP2001577578A patent/JP2004501481A/ja active Pending
  • 2001-04-04 KR KR1020027011416A patent/KR100852917B1/ko not_active IP Right Cessation
  • 2001-04-04 WO PCT/FR2001/000871 patent/WO2001080278A1/fr active Application Filing
  • 2001-04-04 AU AU48413/01A patent/AU4841301A/en not_active Abandoned
  • 2001-04-04 CA CA002406447A patent/CA2406447A1/fr not_active Abandoned
  • 2001-04-11 TW TW090108666A patent/TWI293948B/zh active
• 2002
  • 2002-10-17 US US10/272,367 patent/US6991125B2/en not_active Expired - Fee Related

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