MAGNETOPHORETIC DISPLAY ASSEMBLY AND DRIVING SCHEME

• US 20150277160A1
• Filed: 03/23/2015
• Published: 10/01/2015
• Est. Priority Date: 03/25/2014
• Status: Active Grant

• Current Assignee: E Ink Holdings Incorporated
• Original Assignee: E Ink California, LLC (E Ink Corporation)
• Inventors: Laxton, Peter B.
• Granted Patent: US 10,444,553 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B42D 25/369 Magnetised or magnetisable materials
• CPC Class Codes: G02F 1/09 based on magneto-optical elements, e.g. exhibiting Faraday effect
• CPC Class Codes: G02F 1/094 based on magnetophoretic effect

Abstract

The present invention is directed to a magnetophoretic display assembly and a driving scheme for such a display assembly. It provides a low-cost imaging display assembly which is capable of displaying desired re-writeable images. A single driving element can be used to display images on any number of individual imaging films.

Claims

1. A magnetophoretic display device assembly, comprising:

a magnetic sheet,

a pattern-generating means, and

a magnetophoretic imaging film.

2. The assembly of claim 1, wherein said magnetic sheet comprises magnetic particles dispersed in a polymeric matrix.

3. The assembly of claim 1, wherein the magnetic sheet has a thickness in the range of 12 μ

m to 10 mm.

4. The assembly of claim 1, wherein the pattern-generating means is formed of a neodymium magnet.

5. The assembly of claim 1, wherein the pattern-generating means is an electromagnet.

6. The assembly of claim 1, wherein the pattern-generating means is a stylus.

7. The assembly of claim 1, wherein the pattern-generating means is in the form of a stamp with a pre-determined pattern.

8. The assembly of claim 1, wherein the pattern-generating means is a strong magnet mounted on a computer controlled read-write head.

9. The assembly of claim 1, wherein the magnetophoretic imaging film comprises display cells filled with a magnetophoretic fluid comprising non-magnetic particles and magnetic particles dispersed in a solvent or solvent mixture.

10. The assembly of claim 9, wherein the non-magnetic particles are white.

11. The assembly of claim 10, wherein the white non-magnetic particles are formed from an inorganic pigment.

12. The assembly of claim 10, wherein the white non-magnetic particles are polymer particles having a refractive index of >

1.5 and of a size of >

100 nm.

13. The assembly of claim 9, wherein the magnetic particles are formed from highly magnetic compounds and metals or alloys.

14. The assembly of claim 9, wherein the magnetic particles are formed from a material selected from the group consisting of gamma ferric oxide, acicular magnetite, cobalt-modified or adsorbed ferric oxide, berthollide ferric oxide, chromium dioxide, metals or alloys and organic polyradicals.

15. The assembly of claim 1, useful for anti-counterfeiting or interactive packaging.

16. A method for displaying a desired pattern on a magnetophoretic imaging film, comprising:

a) providing a magnetic sheet and a pattern-generating means;

b) generating the desired pattern on the magnetic sheet with the pattern-generating means; and

c) bringing the magnetophoretic imaging film within magnetic field of the magnetic sheet to allow the desired pattern to appear on the magnetophoretic imaging film.

17. The method of claim 16, wherein the desired pattern remains after the magnetophoretic imaging film is moved outside the magnetic field of the magnetic sheet.

18. The method of claim 16, wherein the desired pattern disappears after the magnetophoretic imaging film is moved outside the magnetic field of the magnetic sheet.

19. The method of claim 16, wherein the magnetophoretic imaging film comprises display cells filled with a magnetophoretic fluid comprising non-magnetic particles and magnetic particles dispersed in a solvent or solvent mixture.

20. The method of claim 19, wherein the non-magnetic particles are white.