Adhesive bonding and miscellaneous chemical manufacture – Methods – Surface bonding and/or assembly therefor
Reexamination Certificate
1999-03-30
2001-10-16
Knable, Geoffrey L. (Department: 1733)
Adhesive bonding and miscellaneous chemical manufacture
Methods
Surface bonding and/or assembly therefor
C156S145000, C156S292000, C156S293000, C359S265000
Reexamination Certificate
active
06302986
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a method for producing an electrochromic device.
2. Prior Art
An electrochromic device is generally produced by sealing the periphery, except for a portion thereof, of a pair of electrically conductive substrates, at least one of which is transparent, placed In a spaced-apart opposing relationship so as to assemble a cell having an injection port formed by the unsealed portion and filling the inner space of the cell by charging through the port an electrolyte or the precursor thereof in a vacuum. The injection port of the cell is then sealed by filling and curing therein a photo-setting or thermosetting acrylic resin or epoxy resin adhesive.
However, such a method for sealing or closing the port requires a step of removing the electrolyte adhered around the injection port prior to filling the adhesive. If the electrolyte is not removed completely, the adhesive can not seal the port sufficiently. Furthermore, the above sealing method fails to obtain satisfactory sealing strength due to an insufficient cure of the adhesive caused by the contact thereof with the electrolyte.
Japanese Laid-Open Patent Publication Nos. 2-114237 and 6-250230 disclose a two-step sealing method to solve the foregoing problems.
Japanese Laid-Open Patent Publication No. 2-114237 discloses a method which comprises a primary sealing and a secondary sealing. In this method, first of all, there is prepared a cell having an opening formed in a selected portion of the peripheral edges of a pair of substrates in opposing relation. After an electrolyte is charged through the opening, the primary sealing is conducted by coating an epoxy resin adhesive to the opening while an external pressure is vertically applied to the substrates followed by releasing the pressure to allow the sealant to enter into the inside of the opening and cure therein. After a certain period of time, the secondary sealing is carried out by coating an epoxy resin adhesive on the peripheral edges of the substrate including the primary sealed portion and allowing the adhesive to cure it self
This method is recognized as being applicable to the production for a electrochromic device of a relatively small size. However, the method is not always suitable for the production for an electrochromic device of a relatively large size because the primary sealing requires the process of applying an external pressure onto the cell. Furthermore, this two-step sealing method is mainly focused on the injection port (opening) provided on the end surface of the cell. Therefore, when this method is employed for producing the large electrochromic device, there may arise a risk that the adhesive would peel off due to the stress applied to the sealing portion upon transportation of the device even though the sealing is completed in a satisfactory manner.
Japanese Laid-Open Publication No. 6-250230 proposes a method by which an electrolyte injection port is sealed vaith a radiation cure type adhesive and then sealed with an epoxy resin adhesive so as to be overlapped with the former adhesive. However, with this method the above risk can not be removed because it also attempts to solve the above problem by providing the electrolyte injection port in the end surface of the cell.
An object of the invention is to provide a method for producing an electrochromic device of which sealing portion of the electrolyte injection port is free from the peel off of the adhesive by providing the electrolyte injection port in one of the two opposing substrates, not in the peripheral edge of the cell, even upon the production of a large size electrochromic device on which stress would possibly applied during the transportation of the device,
Another object of the invention is to provide a method for producing an electrochromic device. The method can avoid completely the contact between an electrolyte and an adhesive to be used for sealing the electrolyte injection port and thus is also free from a risk that the curing reaction of the adhesive is hindered.
SUMMARY OF THE INVENTION
According to the invention, there is provided a method for producing an electrochromic device which comprises:
(a) a step of assembling a hollow cell constituting an electrochromic device by opposing two electrically conductive substrates, at least one of which is transparent and either of which is provided with an injection port for an electrolyte, in a spaced-apart relationship with each other and sealing together the entire peripheral edges of the opposed substrates;
(b) a step of filling the inside of the hollow cell with an electrolyte or the precursor thereof by injecting through the injection port;
(c) a step of sealing temporarily the injection port with a material which can be deformably inserted into the injection port; and
(d) a step of sealing secondarily the temporarily sealed port by applying thereon only an adhesive or a plate-like member over the adhesive.
DETAILED DESCRIPTION OF THE INVENTION
An electrically conductive substrate used for the inventive method means literally a substrate functioning as an electrode. The electrically conductive substrate may be that of which substrate itself is electrically conductive or that of which is not electrically conductive but has an electrode layer disposed on the surface contacting the layer of an electrolyte.
Such an electrically conductive substrate may be iron, copper, silver, aluminum, tin, lead, gold and zinc and,alloys thereof. The nonelectrically conductive substrate may be any type of substrate as long as it has a smooth surface. Specific examples are substrates made of a material such as plastics (synthetic resin), glass, wood and stone.
The electrochromic device produced by the invention includes a pair of such electrically conductive substrates one of which is necessarily transparent. Such an electrically conductive transparent substrate may be produced by laminating an electrode layer on a transparent substrate. The transparent substrate may be colored or colorless glass as well as colored or colorless plastic (synthetic resin). Eligible plastics for this purpose are polyethylene terephthalate, polyamide, polysultone, polyether sulfone, polyether etherketone, polyphenylene sulfide, polycarbonate, polyimide, polymethyl methacrylate and polystyrene.
The term “transparent” used herein designates optical transmission ranging from 10 to 100%. The substrate used for the invention may be flat or curved and may be deformable by stress as long as it has a smooth surface at room temperature.
It is preferred that the electrode layer to be laminated on the non-electrically conductive substrate Is transparent. It is requisite that at least the electrode layer to be laminated on the transparent substrate is transparent. Eligible for the electrode layer are a thin film of metal such as gold, silver, chrome, copper and tungsten or a metal oxide such as ITO (In
2
O
3
—SnO
2
), tin oxide, silver oxide, zinc oxide and vanadium oxide.
The thickness of the electrode is selective within the range of usually 10 to 1,000, preferably 50 to 300 nm. The surface resistance of the electrode may be selected suitably but usually in the range of 0.5-500, preferably 1-50 &OHgr;/sq.
No particular limitation is imposed on the formation method of the electrode layer. Any suitable conventional methods may be selected depending upon the metal and metal oxide constituting the electrode. In general, the formation of the electrode layer is carried out by vacuum evaporation, ion plating, sputtering and a sdoel method In any case, the formation of the electrode should be conducted while maintaining the temperature of the substrate within the range of 100-350° C.
The electrode layer may partially provided with an opaque electrode-activator in order for the purpose of imparting oxidation-reduction capability and increasing electric double layer capacitance. In this case, if it is necessary to maintain the transparency of the electrode, the optical transmission of the whole electrode is kept within t
Kobayashi Yukio
Nishikitani Yoshinori
Toya Tomohiro
Akin Gump Strauss Hauer & Feld L.L.P.
Knable Geoffrey L.
Nippon Mitsubishi Oil Corp.
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