FR2741460A1 - Filling active liquid into cell compartments cells bounded by parallel substrates - Google Patents

Abstract

The assembly is placed on the first substrate (2) and has several portions (4, 5, 6) enabling each cell (7, 8, 9) to have an opening (7a, 8a, 9a) towards a distribution chamber (20) with a single filler hole (21) linking with the exterior. The second substrate (3) is fixed on the upper surface of the framework according to a procedure adapted to the assembly used. The active liquid is filled through the hole and a stopper material is introduced into the distribution chamber and seals the elemental openings. The filling may be along an injection axis parallel to the plane of the substrates or it may be perpendicular to this plane and to that of the injection axis across the openings.

Description

METHOD FOR FILLING AND SEALING A
COMPARTMENTAL CELL AND CELL THUS OBTAINED
The present invention relates to a method of filling and sealing a compartmentalized cell, making it possible to fill at once with an active liquid material the compartments formed by spaces included between the plates of several contiguous elementary cells situated in the same plane, then isolate the compartments from each other by a single sealing operation.

 More particularly, the invention relates to such a method making it possible to fill, for example, photoelectrochemical cells which can be placed in series, or liquid crystal cells making it possible to obtain on the same display contrasts, or even different colors in well delimited areas, for example by applying different voltages to the electrodes of each cell.

 The invention also relates to compartmentalized cells obtained by said process, at economically advantageous conditions, due to the simplification of certain manufacturing steps.

Transparent cells comprising two facing plates provided with electrodes and an assembly frame delimiting a space filled with a liquid crystal composition are well known in the prior art and several documents relate to their manufacture according to particular modes, such as indicated below
Patent GB 2 039 679 discloses a manufacturing process making it possible to fill in a single operation a batch of cells arranged on the same support surrounded by a peripheral sealing gasket, each cell then being detached from the support and individually sealed.

 In patent EP 0 113 838, the cell comprises several compartments communicating with each other, and which can be filled with a composition of liquid crystals by means of a single orifice, the sealing of which makes it possible to close the cell as a whole, without however isolate the compartments from each other.

 In GB patent 2,049,214, the method described allows the simultaneous filling of a stack of liquid crystal cells intended to improve the resolution of the display. For this purpose, holes are made in the plates, then aligned so as to allow in a single operation their filling and the sealing of at least one external orifice, which however does not make it possible to isolate the media from each other. assets of each cell.

 GB patent 2,064,843 discloses a method for obtaining a large surface display device, by filling cells two by two, through a slot made in one of the substrates, said slot then being sealed with a cord or an adhesive tape to form a chain of isolated cells located in the same plane. As is understood, each filling and sealing operation can only concern two cells at the same time.

 From the above, it appears that the methods of the prior art essentially relate to liquid crystal cells, either for batch production, or for simultaneous filling of several compartments of the same cell or of a cell assembly. , at most two of which can be separated by the sealing operation, while remaining on the same support.

 The main object of the invention is therefore to remedy the abovementioned drawbacks of the prior art by providing a method in which a cell compartmentalized into several elementary cells is provided with a single orifice, the assembly frame and the openings of each cell. elementary being shaped so that it is possible to fill in one go all the elementary cells with the same active liquid substance and to isolate the liquid media of each elementary cell by a single sealing operation.

 The invention relates more particularly to such a method for filling a compartmentalized cell constituted by at least two elementary cells.

 The invention also relates to a cell obtained by said method, and more particularly a cell in which the elementary cells are photoelectrochemical cells which can be placed in series. The cell thus obtained has no limitation as to its surface, but the invention relates even more particularly to such a compartmentalized cell intended to form the crystal or the dial of a timepiece, and to supply the movement with the useful voltage at its operation.

To this end, the subject of the invention is a method of filling with an active liquid material a cell compartmentalized in several elementary cells and the sealing of said cell by means of a sealing material, in which each elementary cell provided an opening is delimited, on the one hand by a first flat substrate and by a second substrate parallel to the first, at least one of the two substrates being transparent, on the other hand by an assembly frame formed by several portions interconnected, characterized in that it comprises the stages consisting in
- deposit on the same first substrate an assembly means to conform the assembly frame of each elementary cell by orienting their respective openings towards a distribution chamber communicating with the external medium by means of a single filling orifice;
- Fix a second substrate on the upper faces of the frames of all the elementary cells according to a process adapted to the assembly means used;
- fill all the elementary cells with the active liquid material through the filling orifice;
- Introduce into the distribution chamber the sealing material allowing all the openings of the elementary cells to be sealed at once.

 The invention also relates to a cell compartmentalized into several elementary cells, containing an active liquid material sealed by a sealing material, in which each elementary cell provided with an opening is delimited on the one hand by a first planar substrate and by a second substrate parallel to the first, at least one of the two substrates being transparent, on the other hand by an assembly frame formed by several portions interconnected, the assembly frame of each elementary cell being located on the same first substrate, the respective openings of each elementary cell opening into a distribution chamber in communication with the external medium through an orifice, said chamber containing the obturation material making it possible to isolate the elementary cells from each other and from the external medium.

 As a sealing material, one can choose from polymerizable, hot-melt and thermosetting materials well known to those skilled in the art in the techniques of manufacturing display cells.

When the assembly means can be chosen from an adhesive, a sinterable glass and a polymerizable, hot-melt or thermosetting material, said assembly means being able to incorporate spacers (balls or sticks) in its composition, as could be equivalent incorporate them into the active liquid material.

The deposition of the assembly means on the first substrate is carried out according to methods known to those skilled in the art, for example by screen printing, pad printing or by application by means of a motorized dispenser-dispenser. The attachment of the second substrate to the assembly frame is of course a function of the assembly means used, and will consist, for example, in the case of a polymerizable material to cause polymerization by irradiation, or temperature rise.

 The method according to the invention thus makes it possible to reduce the number of operations, and consequently the production costs when it is sought to obtain a compartmentalized lamellar cell in which all the elementary cells must cooperate for the same function in a given product. This is for example the case for a photoelectrochemical cell, in which the elementary cells are intended to be placed in series to obtain a sufficient voltage for supplying the movement of a timepiece. In this case, each elementary cell will have , for example, the configuration described in document US Pat. No. 5,441,827, in which two transparent substrates comprise a transparent electrode, the second substrate then being coated with a nanostructured layer of a photoelectrochemically active semiconductor oxide, the active liquid material filling the cell being an electrolyte.

 When the compartmentalized cell is intended for a display, each elementary cell is formed in a known manner by two substrates provided with structured electrodes, the active liquid material then being a composition of liquid crystals.

 Advantageously, the assembly frames of the elementary cells have common portions so as to give the compartmentalized cell a defined geometric outline, such as a circle, an ellipse, a square or a rectangle. Depending on the shape of this geometric contour and the unitary or batch manufacturing method, it may be useful, to perfect this contour, to perform an additional machining operation along said exterior contour of the assembly frame, and in particular at the filling opening.

Other advantages and characteristics of the invention will appear on reading the description of compartmentalized photoelectrochemical cells, given by way of nonlimiting examples in conjunction with the appended drawings in which
- Figure 1 shows a perspective view, partially broken away of a first embodiment before the filling, sealing and finishing operation;
- Figures 2 to 4 schematically represent the different phases of the method according to the invention;
FIG. 5 represents a partially cut away top view of a second embodiment, and
- Figure 6 shows a top view of a third embodiment.

 Referring to Figure 1, there is shown a photoelectrochemical cell 1 in the form of a disc, compartmentalized into three elementary cells 7, 8, 9 of substantially equal surface, said elementary cells being intended to be placed in series. In the example described, cell 1 is intended to form the crystal or the dial of a timepiece. It is therefore small and can be manufactured in batches from substrates common to several compartmentalized cells.

Each cell is then cut along geometric lines, before the filling and sealing operations, as shown diagrammatically in FIG. 1 in the form of a square in dashed lines. The internal volume of each cell is delimited on the one hand by a first substrate 2 common to the three elementary cells and by a second substrate 3 parallel to the first, on the other hand by an assembly frame formed by several portions 4, 5, 6 interconnected. The portion 4 is arranged between the substrates 2 and 3, in the form of an open ring at the level of an orifice 21. A portion 5, in the form of an arc of a circle joining a zone 4a of the portion 4 and a zone substantially diametrically opposite, defines with the portion 4 the volume of a first elementary cell 7 and its opening 7a which opens into a distribution chamber 20, in the zone diametrically opposite to the zone 4a. Similarly, a portion 6, in an arc of a circle, symmetrical with the portion 5, defines with the portion 4 the interior volume of a second elementary cell 9 and its opening 9a. The portions 5 and 6 then delimit the interior volume of a third elementary cell 8 and its opening 8a. As can be seen, all of these three elementary cells are designed so that their respective openings 7a, 8a, 9a all open into the same chamber 20, in communication with the external environment by means of the orifice 21.

 In FIG. 1, the chamber 20 has an extension 22 formed by an extension of the peripheral seal 4 between the substrates 2 and 3. Such a configuration makes it possible to facilitate, even to automate, the filling and sealing operations which will be explained more far, but is not absolutely necessary, as will be seen in the other embodiments.

 To produce such a compartmentalized photoelectrochemical cell, it is necessary to use transparent substrates 2, 3 coated with transparent electrodes structured to be isolated from one another at the level of portions 5 and 6, of the assembly frame, common to two cells. contiguous elementaries. The electrodes supported by the substrate 2, or in an equivalent manner by the substrate 3, have on their surface a nanostructured layer of a photoelectrochinically active semiconductor oxide. The three cells are placed in series according to known modes, by resumption of electrode contacts of each cell, either at the periphery, for example at the level of the zone 4a, or at the level of the portions 5, 6 common to two elementary cells by means of an anisotropic connection of a portion d electrode on a substrate with an electrode portion facing the other substrate. Equivalently, the electrical connections allowing the three cells to be placed in series can be obtained by depositing on the entire surface of the substrate 2 a structured electrode only at the level of the portion 5, that is to say by electrically insulating one of the electrodes of the cell 7 with respect to the electrodes of the cells 8, 9, and vice versa by depositing on the substrate 3 an electrode structured only at the level of the portion 6, that is to say electrically insulating one of the electrodes of the cell 9 with respect to the electrodes of the cells 7, 8, the photoelectrochemically active material then being deposited on the electrodes 7 and 9 carried by the substrate 2 and on the electrode 8 carried by the substrate 3, or vice versa.

 The compartmentalized cell which has just been described can be produced by methods known to those skilled in the art, both as regards the choice of materials (substrate, assembly means, obturation material, electrodes, material electrochemically active, etc.), as regards the processing of said materials.

On the other hand, this description makes it possible to understand the essential role played by the arrangement of the openings of each cell which are in communication, not directly with the external medium, but with an intermediate space, the chamber 20 which is alone in communication with the medium outside via the orifice 21. This role will be better understood with reference to FIGS. 2 to 4 which schematically represent a top view of the cut-away part of FIG. 1 during the various phases of the process.

 FIG. 2 represents the filling phase through an orifice 21 of the chamber 20 with an electrolyte 23 which is distributed in the elementary cells 7, 8 and 9 through their respective openings 7a, 8a and 9a.

 FIG. 3 represents the sealing phase with the sealing material 24, for example silicone, which makes it possible to seal both the filling orifice 21 and the openings 7a, 8a and 9a, while simultaneously isolating the each cell's electrolytic media from each other. The control of the progress of the material 24 through the openings 7a, 8a and 9a can be carried out simply by adjusting the quantity of silicone injected to the volume of the chamber 20 to be filled. When using another sealing material, for example a photopolymerizable substance, it is possible, for example, to use selective irradiation of the openings making it possible to accelerate at this location the polymerization of the material forming the plug.

 In Figure 4, there is shown the additional step of cutting the substrates 2 and 3 along the peripheral portion 4 of the assembly frame by eliminating the extension 22 and the corresponding part of the plug, so as to improve the 'final aspect of the compartmentalized cell thus obtained, or to be able to integrate it more easily into a finished product, namely in the example described, as a crystal or dial of a timepiece.

 FIG. 5 represents, in a partially cut away top view, another example of compartmentalized cell having four elementary cells 7, 8, 9 and 10 arranged on a rectangular support, with openings 7a, 8a, 9a and 10a opening into a chamber 20 in communication with the outside environment via the orifice 21 allowing the filling and sealing of said cell. As can be seen, the rectangular shape makes it possible to save the extension 22 shown in FIG. 1.

 In the two previous examples (FIGS. 1 and 5), the openings of each elementary cell and the single filling orifice are located in the same plane, that is to say that the axes of injection of the active liquid material, through the chamber 20, in each elementary cell, then the obturation material in the chamber 20 are substantially parallel to the plane of the substrates 2, 3. In other words the orifice 21 and the openings of each elementary cell are formed in or between the portions of the assembly frame.

 In FIG. 6, on the contrary, a compartmentalized cell has been shown, the four elementary cells 7, 8, 9, 10 of which are arranged in stars on a square support, in which the axis of injection of the orifice 21 is located in a plane perpendicular to the plane in which the axes of injection of the openings 7a, 8a, 9a and 10a of each elementary cell are located. In other words, the chamber 20 occupies a central position and the orifice 21 is formed through one of the substrates 2 or 3.

 Without departing from the scope of the invention, the person skilled in the art is able to choose other shapes for the support of the assembly or for the distribution chamber of the active liquid material, just as he can choose to produce assemblies with cells of different volumes, the number of cells being limited only by technical constraints making it possible to orient all the openings towards the same distribution chamber.

Claims (13)

 1. A method of filling with an active liquid material (23) a compartmentalized cell (1) in several elementary cells (7, 8, 9) and sealing said cell by means of a sealing material (24) in which each elementary cell provided with an opening (7a, 8a, 9a) is delimited, on the one hand by a first flat substrate (2) and by a second substrate (3) parallel to the first, at least one of the two substrates (2 or 3) being transparent, on the other hand by an assembly frame formed by several portions (4, 5, 6) connected together, characterized in that it comprises the steps consisting in  - deposit on the same first substrate (2) an assembly means to conform the assembly frame of each elementary cell by orienting their respective openings (7a, 8a, 9a) towards a distribution chamber (20) communicating with the medium exterior by means of a single filling orifice (21);  - fixing a second substrate (3) on the upper faces of the frames (4, 5, 6) of all the elementary cells (7, 8, 9) according to a process adapted to the assembly means used;  - fill all the elementary cells with the active liquid material (23) through the filling orifice (21); and  - Introducing into the distribution chamber (20) the sealing material making it possible to seal in one go all the openings (7a, 8a, 9a) of the elementary cells (7, 8, 9).  2. Method according to claim 1, characterized in that the filling of the cells (7, 8, 9) with active liquid material (23) and of the distribution chamber with sealing material (24) is carried out through the openings (7a, 8a, 9a) and the orifice (21) along injection axes substantially parallel to the plane of the substrates (2, 3).  3. Method according to claim 1, characterized in that the filling of the cells (7, 8, 9) in active liquid material (23) and of the distribution chamber (20) in obturation material (24) is carried out at through the orifice (21) along an injection axis located in a plane substantially perpendicular to the plane of the substrates (2, 3) and to the injection axes through the openings (7a, 8a, 9a).  4. Method according to claim 1, characterized in that the sealing material is chosen from polymerizable, hot-melt and thermosetting materials.  5. Method according to claim 1, characterized in that the assembly means is chosen from an adhesive, a sinterable glass and a polymerizable material and in that the deposition of said assembly means is carried out by a process chosen from screen printing , pad printing and application by a motorized dispenser-dispenser.  6. Method according to claim 1, characterized in that it allows the filling of a compartmentalized cell composed of at least two elementary cells having in common portions (5, 6) of the assembly frame, said compartmentalized cell being isolated from the outside environment by a peripheral portion (4) of the assembly frame defining the geometric shape of said cell.  7. Cell compartmentalized into several elementary cells (7, 8, 9) containing an active liquid material (23) sealed by a sealing material (24), in which each elementary cell provided with an opening (7a, 8a, 9a ) is delimited on the one hand by a first flat substrate (2) and by a second substrate (3) parallel to the first, at least one of the two substrates (2 or 3) being transparent, on the other hand by a frame assembly formed of several portions (4, 5, 6) interconnected, characterized in that the assembly frame of each elementary cell is located on the same first substrate (2), the respective openings (7a, 8a, 9a) of each elementary cell opening into a distribution chamber (20) in communication with the external environment through an orifice (21), said chamber containing the obturation material (24) making it possible to isolate the elementary cells (7, 8 , 9) from each other and from the outside environment.  8. compartmentalized cell according to claim 7, characterized in that the orifice (21) and the openings (7a, 8a, 9a) are formed in or between the portions (4, 5, 6) of the assembly frame.  9. compartmentalized cell according to claim 7, characterized in that the orifice (21) is formed in one of the substrates (2 or 3), at the level of the distribution chamber (20) and that the openings (7a, 8a, 9a) are formed in portions of the assembly frame forming the walls of said distribution chamber.  10. compartmentalized cell according to any one of claims 7 to 9, characterized in that portions (5, 6) of the assembly frame are common to two contiguous elementary cells, and in that a peripheral portion (4) of the assembly frame isolates the elementary cells from the external environment and delimits the geometric shape of said compartmentalized cell.  11. compartmentalized cell according to any one of claims 7 to 10, characterized in that each elementary cell is a photoelectrochemical cell in which each substrate is coated with a transparent electrode, one of the electrodes comprising a layer of a material an electrochemically active semiconductor, and in which the active liquid material is an electrolyte, the electrodes of said elementary cells being isolated from one another and capable of being connected in series.  12. compartmentalized cell according to any one of claims 7 to 10, characterized in that each elementary cell is a display cell in which each substrate is coated with an electrode, at least one of the electrodes being structured and in wherein the active liquid material is a liquid crystal composition, the structured electrodes of said elementary cells being isolated from each other and being able to be excited according to different modes.  13. compartmentalized cell according to claim 11 or 12, characterized in that said cell constitutes the crystal or the dial of a timepiece.