Optical switching device with hard spacers exhibiting thermoplastic property at a temperature not higher than 150.degree. C. and fabrication process
First Claim
1. An optical switching device comprising:
- at least two substrates disposed facing opposite to each other;
hard spacers which are thermally undeformable, the hard spacers being coated with a thermoplastic resin exhibiting its thermoplastic property at a temperature not higher than 150°
C.;
soft spacers which are larger in size than the hard spacers and adapted to deform and then cure by heat to adhere to the substrates;
the hard spacers and the soft spacers being disposed between the substrates in such a manner that a spacing between the substrates is kept constant by diameters of the hard spacers;
a medium with an optical switching function retained in a gap defined between the substrates; and
a sealer which seals the periphery of the gap between the substrates;
wherein the sealer is made of a thermosetting resin having a thermosetting point equal to or higher than a thermosetting point of the soft spacers.
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Accused Products
Abstract
An optical switching device of the present invention includes at least two substrates disposed facing opposite to each other. By scattering hard spacers which are thermally undeformable and soft spacers which are larger in size than the hard spacers and adapted to deform and then to cure by heat to adhere to the substrates, the spacing defined between the substrates is kept constant by diameters of the hard spacers. A medium having an optical switching function is retained in a gap defined between the substrates. The periphery of the gap between the substrates is sealed with a sealer. The sealer is made of a thermosetting resin having a thermosetting point equal to or higher than the thermosetting point of the soft spacers.
59 Citations
34 Claims
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1. An optical switching device comprising:
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at least two substrates disposed facing opposite to each other; hard spacers which are thermally undeformable, the hard spacers being coated with a thermoplastic resin exhibiting its thermoplastic property at a temperature not higher than 150°
C.;soft spacers which are larger in size than the hard spacers and adapted to deform and then cure by heat to adhere to the substrates; the hard spacers and the soft spacers being disposed between the substrates in such a manner that a spacing between the substrates is kept constant by diameters of the hard spacers; a medium with an optical switching function retained in a gap defined between the substrates; and a sealer which seals the periphery of the gap between the substrates; wherein the sealer is made of a thermosetting resin having a thermosetting point equal to or higher than a thermosetting point of the soft spacers. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A process for fabricating an optical switching device, comprising the steps of:
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scattering, on at least one of a pair of substrates for forming a liquid crystal space, hard spacers which are thermally-undeformable and soft spacers which are larger in size than the hard spacers and adapted to deform and then to cure by heat to adhere to the substrates; heating and pressing the pair of substrates in an opposing relation to combine the substrates into a body adhered by the soft spacers and with a spacing therebetween kept constant by the hard spacers; and filling a liquid crystal between the substrates from a liquid crystal introduction opening formed on two opposing peripheral sides of the combined substrates. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. An optical switching device comprising:
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at least two substrates disposed facing opposite to each other; hard spacers which are thermally undeformable; soft spacers which are larger in size than the hard spacers and adapted to deform and then cure by heat to adhere to the substrates; the hard spacers and the soft spacers being disposed between the substrates in such a manner that a spacing between the substrates is kept constant by diameters of the hard spacers; a medium with an optical switching function retained in a gap defined between the substrates; and a sealer which seals the periphery of the gap between the substrates; wherein the sealer is made of a thermosetting resin having a thermosetting point equal to or higher than a thermosetting point of the soft spacers; and the hard spacers, the soft spacers and the sealer each have a linear position coefficient of 10-4 to 10-6 /°
C. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
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33. An optical switching device comprising:
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at least two substrates disposed facing opposite to each other; hard spacers which are thermally undeformable; soft spacers which are larger in size than the hard spacers and adapted to deform and then cure by heat to adhere to the substrates, the soft spacers being formed of a phenol resin having a thermosetting time of about one hour at a thermosetting point of about 120°
C., and the sealer is formed of an epoxy resin having a thermosetting time of about one hour at a thermosetting point of about 140°
C.;the hard spacers and the soft spacers being disposed between the substrates in such a manner that a spacing between the substrates is kept constant by diameters of the hard spacers; a medium with an optical switching function retained in a gap defined between the substrates; and a sealer which seals the periphery of the gap between the substrates; wherein the sealer is made of a thermosetting resin having a thermosetting point equal to or higher than a thermosetting point of the soft spacers.
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34. An optical switching device comprising:
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at least two substrates disposed facing opposite to each other; hard spacers which are thermally undeformable; soft spacers which are larger in size than the hard spacers and adapted to deform and then cure by heat to adhere to the substrates; the hard spacers and the soft spacers being disposed between the substrates in such a manner that a spacing between the substrates is kept constant by diameters of the hard spacers; a medium with an optical switching function retained in a gap defined between the substrates; and a sealer which seals the periphery of the gap between the substrates; the thermosetting point of the sealer is higher than the thermosetting point of the soft spacers, and said at least two substrates are heated stepwise, first at the thermosetting point of the soft spacers and then at the thermosetting point of the sealer.
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Specification