IMAGE DISPLAY APPARATUS

• US 3,806,229 A
• Filed: 06/23/1971
• Issued: 04/23/1974
• Est. Priority Date: 06/27/1970
• Status: Expired due to Term

• Current Assignee: Cornelis Johannes Schoot, Johannes Jacobus Ponjee
• Original Assignee: Cornelis Johannes Schoot, Johannes Jacobus Ponjee
• Inventors: Schoot, Cornelis Johannes, Ponjee, Johannes Jacobus
• Primary Examiner(s): Van Horn, Charles E.
• Assistant Examiner(s): Wittenberg, M. B.
• Application Number:
  US05/155,871
• Time in Patent Office: 1,035 Days
• Field of Search: 96/1 252/408 350/16LC 340/334 204/181
• US Class Current: 359/273
• CPC Class Codes: C07D 213/22 containing two or more pyridine rings directly linked together, e.g. bipyridyl
• CPC Class Codes: C09K 9/02 Organic tenebrescent materials
• CPC Class Codes: G02F 1/1503 caused by oxidation-reduction reactions in organic liquid solutions, e.g. viologen solutions

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.

Claims

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.

3. The image display apparatus of claim 2 wherein the anion is the boron tetrafluoride ion.

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.

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.

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.

7. The image display apparatus as claimed in claim 6, wherein the adjuvant is a tetra-substituted hydroquinone.

8. The image display apparatus as claimed in claim 7, wherein the adjuvant is a tetrahalogenohydroquinone.

9. The image display apparatus as claimed in claim 8, wherein the adjuvant is tetrachlorohydroquinone.

10. The image display apparatus as claimed in claim 1 wherein the adjuvant used is a ferrous salt.

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.

12. The image display apparatus as claimed in claim 1 wherein the adjuvant used is a 1,4-di(dialkylamino) benzene.

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.

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.

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.

16. The image display apparatus as claimed in claim 1 wherein a titanium dioxide pigment is dispersed in the solution.

17. The image display apparatus as claimed in claim 1 wherein water or an aprotic solvent is used as the solvent.

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.

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.

20. The image display apparatus as claimed in claim 5, characterized in that the solution contains an acid.

21. The image display apparatus as claimed in claim 20, wherein acetonitrile is used as the solvent.

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.