IMAGE DISPLAY APPARATUS
First Claim
2. The image display apparatus of claim 1 wherein the anion of the reversibly reducible organic substance is a member selected from the group consisting of perchlorate, boron tetrafluoride, phosphate and halide ions.
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Accused Products
Abstract
The invention relates to an image display apparatus provided with at least two electrodes to which a direct voltage or a square-wave or alternating voltage may be applied. The electrodes are in contact with a solution of a reversible reducible organic substance of the formula I and an adjuvant. Suitable adjuvants are substituted hydroquinones, ferrous salts and 1,4-di (dialkylamino) benzenes. When the voltage is applied compounds of the formula I are reduced to intensely coloured radical ions. Oxidation of the adjuvant takes place at the anode.
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Citations
22 Claims
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2. The image display apparatus of claim 1 wherein the anion of the reversibly reducible organic substance is a member selected from the group consisting of perchlorate, boron tetrafluoride, phosphate and halide ions.
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3. The image display apparatus of claim 2 wherein the anion is the boron tetrafluoride ion.
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4. The image display apparatus of claim 1 wherein the electrodes are made of a material selected from the group consisting of stannic oxide, indium oxide, platinum, palladium and gold.
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5. The image display apparatus as claimed in claim 1 wherein the adjuvant is a substituted hydroquinone which in water has an oxidation reduction potential of at least 0.7 volts measured with respect to the standard hydrogen electrode.
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6. The image display apparatus as claimed in claim 5 wherein a hydroquinone substituted with a moiety selected from the group consisting of halogen, CN, CF3, CC13 and SLF3 is present.
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7. The image display apparatus as claimed in claim 6, wherein the adjuvant is a tetra-substituted hydroquinone.
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8. The image display apparatus as claimed in claim 7, wherein the adjuvant is a tetrahalogenohydroquinone.
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9. The image display apparatus as claimed in claim 8, wherein the adjuvant is tetrachlorohydroquinone.
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10. The image display apparatus as claimed in claim 1 wherein the adjuvant used is a ferrous salt.
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11. The image display apparatus as claimed in claim 10, wherein the ferrous salt is a member sElected from the group consisting of ferrous boron tetrafluoride, ferrous acetate and ferrous chloride.
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12. The image display apparatus as claimed in claim 1 wherein the adjuvant used is a 1,4-di(dialkylamino) benzene.
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13. The image display apparatus as claimed in claim 12, wherein the adjuvant is a 1,4-di(dialkylamino)-benzene in which the alkyl groups contain up to five carbon atoms.
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14. The image display apparatus as claimed in claim 1 wherein the reducible organic substance and the adjuvant are present in concentrations of at least 0.01 mole per litre.
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15. The image display apparatus as claimed in claim 5 wherein the apparatus contains a saturated solution of the substituted hydroquinone with residual undissolved substituted hydroquinone.
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16. The image display apparatus as claimed in claim 1 wherein a titanium dioxide pigment is dispersed in the solution.
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17. The image display apparatus as claimed in claim 1 wherein water or an aprotic solvent is used as the solvent.
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18. The image display apparatus as claimed in claim 1 wherein the organic reducible substance used is a halide or a boron tetrafluoride of the formula I, the solvent used is water, and the adjuvant used is a ferrous salt or a 1, 4-di(dialkylamino) benzene.
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19. The image display apparatus as claimed in claim 1 wherein the organic reducible substance used is a perchlorate or a boron tetrafluoride of the formula I, the adjuvant used is a ferrous salt or a 1,4-di(dialkylamino) benzene and the solvent used is acetic acid anhydride.
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20. The image display apparatus as claimed in claim 5, characterized in that the solution contains an acid.
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21. The image display apparatus as claimed in claim 20, wherein acetonitrile is used as the solvent.
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22. The image display apparatus as claimed in claim 20, wherein the solution contains from about 0.5 percent to about 10 percent by weight of an acid.
Specification