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CN-122029481-A - Color electro-optic display comprising a light resistance additive

CN122029481ACN 122029481 ACN122029481 ACN 122029481ACN-122029481-A

Abstract

A color electro-optic display (100, 200, 300) comprising an electrophoretic medium (122, 222), the electrophoretic medium (122, 222) comprising different types of charged pigment particles (262,272), at least one of which is an electro-mechanically active compound, a light-fast additive, and a non-polar liquid. The light fastness additive is an electron acceptor and it improves the light fastness of the color electrophoretic display.

Inventors

  • S.J. Telfer
  • R. Casado
  • S. Yegorov
  • A - L - latus

Assignees

  • 伊英克公司

Dates

Publication Date
20260512
Application Date
20241023
Priority Date
20231031

Claims (20)

  1. 1. A color electro-optic display comprising, in order: A first electrode layer including a light-transmitting electrode; A layer of electro-optic material comprising an electrophoretic medium encapsulated in a plurality of microcells or microcapsules, the electrophoretic medium comprising a plurality of charged pigment particles of a first type, a plurality of charged pigment particles of a second type, a photostable additive that is an electron acceptor, and a nonpolar liquid, the photostable additive being present in the electrophoretic medium in an amount of 0.1 to 6.0 weight percent, based on the weight of the electrophoretic medium; And a second electrode layer including a plurality of pixel electrodes.
  2. 2. The color electro-optic display of claim 1, wherein the light resistant additive is selected from the group consisting of substituted 1, 4-benzoquinone, substituted 1, 2-benzoquinone, substituted naphthoquinone, and substituted anthraquinone, wherein the substituted 1, 4-benzoquinone, the substituted 1, 2-benzoquinone, the substituted naphthoquinone, and the substituted anthraquinone have at least one substituent comprising an alkyl, cycloalkyl, or alkenyl group, and wherein the at least one substituent has 10 to 120 carbon atoms.
  3. 3. The color electro-optic display of claim 2, wherein the substituted 1, 2-benzoquinone, the substituted 1, 4-benzoquinone, the substituted naphthoquinone, and the substituted anthraquinone have at least one substituent represented by formula I or formula II, wherein n is an integer from 2 to 20, and wherein m is an integer from 1 to 20.
  4. 4. The color electro-optic display of claim 2 wherein the light resistant additive is a substituted 1, 4-benzoquinone represented by formula III, Wherein R 1 is represented by formula I or formula II, wherein n is an integer from 2 to 20, and m is an integer from 1 to 20, and wherein R 2 to R 4 are independently selected from hydrogen, alkyl groups, alkenyl groups, aryl groups, and heteroatom groups containing heteroatoms of groups V-VII of the periodic Table.
  5. 5. The color electro-optic display of claim 4, wherein R 1 is represented by formula II, m is an integer from 2 to 20, and wherein each of R 2 、R 3 and R 4 is independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups.
  6. 6. The color electro-optic display of claim 5, wherein R 2 is a methyl group, and wherein R 3 and R 4 are methoxy groups.
  7. 7. The color electro-optic display of claim 5, wherein R 2 is hydrogen, and wherein R 3 and R 4 are methyl groups.
  8. 8. The color electro-optic display of claim 7 wherein the light resistant additive is represented by formula IV or formula V, 。
  9. 9. The color electro-optic display of claim 2 wherein the molecular structure of the light resistant additive is a substituted benzoquinone represented by formula VI, , Wherein each of R 5 、R 6 and R 7 can be independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups, and wherein o is an integer from 2 to 20.
  10. 10. A color electro-optic display as defined in claim 2, wherein the light resistance additive is a substituted naphthoquinone represented by formula VII, Wherein each of R 8 、R 9 、R 10 、R 11 and R 12 can be independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups, and wherein p is an integer from 2 to 20.
  11. 11. A color electro-optic display as defined in claim 2, wherein the light resistance additive is a substituted naphthoquinone represented by formula VIII, Wherein each of R 13 、R 14 、R 15 、R 16 and R 17 can be independently selected from hydrogen, alkyl, alkenyl, and alkoxy groups, and wherein q is an integer from 2 to 20.
  12. 12. The color electro-optic display of claim 11, wherein the molecular structure of the light resistant additive is represented by formula VIII, wherein R 13 、R 14 、R 15 、R 16 is hydrogen and R 17 is methyl.
  13. 13. The color electro-optic display of claim 12 wherein q is selected from the group consisting of 3, 4, 7 and 9.
  14. 14. A color electro-optic display according to any one of claims 1 to 13 wherein the electrophoretic medium further comprises a plurality of charged pigment particles of a third type and a plurality of charged pigment particles of a fourth type.
  15. 15. The color electro-optic display of claim 14, wherein the first, second, third, and fourth types of charged pigment particles have a color selected from the group consisting of white, black, cyan, magenta, yellow, blue, green, and red.
  16. 16. The color electro-optic display of claim 14, wherein the first, second, third and fourth types of charged pigment particles are white, cyan, magenta and yellow, respectively.
  17. 17. A colour electro-optic display according to any one of claims 1 to 16 wherein the layer of electro-optic material comprises a plurality of microcapsules and a binder.
  18. 18. The color electro-optic display of claim 17, wherein the color electro-optic display further comprises a first adhesive layer disposed between the layer of electro-optic material and the second electrode layer.
  19. 19. The color electro-optic display of claim 18, wherein the color electro-optic display further comprises a second adhesive layer disposed between the layer of electro-optic material and the first electrode layer.
  20. 20. The color electro-optic display of any one of claims 1-16, wherein the layer of electro-optic material comprises a plurality of microcells, each microcell of the plurality of microcells having a microcell bottom, a partition wall, an opening, and a sealing layer spanning the opening, the sealing layer being adjacent to the second electrode layer.

Description

Color electro-optic display comprising a light resistance additive RELATED APPLICATIONS The present application claims priority from U.S. provisional patent application No. 63/546,536 filed on month 31 of 2023, which is incorporated by reference in its entirety with all other patents and patent applications disclosed herein. Background The invention relates to a color electro-optic display comprising a layer of electro-optic material having an electrophoretic medium comprising a light-fast additive. The light fastness additive improves the light fastness of the color electro-optic display. The electrophoretic medium of the electro-optic material layer of the electro-optic display further comprises charged particles in a non-polar liquid. The terms "bistable" and "bistable" are used herein in their conventional sense in the art to refer to a display comprising display elements having a first display form and a second display form that differ in at least one optical property, and such that after any given element has been driven to assume its first display form or second display form by an addressing pulse of finite duration, after the addressing pulse has terminated, the state will last at least a multiple, for example at least four times the shortest duration of the addressing pulse required to change the state of the display element. It is shown in U.S. Pat. No. 7,170,670 that some particle-based electrophoretic displays capable of displaying gray scale are stable not only in their extreme black and white states, but also in their intermediate gray states, and so are some other types of electro-optic displays. This type of display is properly referred to as "multi-stable" rather than bi-stable, but for convenience the term "bi-stable" may be used herein to encompass both bi-stable and multi-stable displays. The term "electro-optic" when applied to a material or display is used herein in its conventional sense in the imaging arts to refer to a material having a first display state and a second display state that differ in at least one optical property, the material being changed from its first display state to its second display state by application of an electric field to the material. Although the optical property is typically a color perceptible to the human eye, it may be another optical property such as light transmittance, reflectivity, luminescence, or in the case of a display intended for machine reading, a pseudo color in the sense of a change in reflectivity of electromagnetic wavelengths outside the visible range. Some electrophoretic media are solid in the sense that the material has a solid outer surface, although the media may and typically does have a liquid or gas filled space inside. For convenience, a display using a solid state electrophoretic medium may be hereinafter referred to as a "solid state electrophoretic display". Some types of electro-optic displays are known. One type of electro-optic display is a rotating bichromatic cell type, as described in, for example, U.S. Pat. Nos. 5,808,783, 5,777,782, 5,760,761, 6,054,071, 6,055,091, 6,097,531, 6,128,124, 6,137,467 and 6,147,791 (although this type of display is commonly referred to as a "rotating bichromatic ball" display, the term "rotating bichromatic cell" is preferred because it is more accurate because in some of the above-mentioned patents the rotating cell is not spherical). Such displays use a large number of small bodies (typically spherical or cylindrical) with two or more portions with different optical properties, as well as internal dipoles. These small bodies are suspended in liquid-filled vesicles within the matrix, which are filled with liquid, allowing the small bodies to freely rotate. The appearance of the display is changed by applying an electric field thereto, thus rotating the small body to a different position and changing that part of the small body which is seen through the viewing surface. Electro-optic media of this type are typically bistable. Another type of electro-optic display uses electrochromic media, for example in the form of a nano-color film comprising an electrode formed at least in part of a semiconductor metal oxide and a plurality of reversibly color-changing dye molecules attached to the electrode, see, for example, O' Regan, b. Et al, nature 1991,353,737, and Wood, d., information Display,18 (3), 24 (March 2002). See also Bach, u. et al, adv. mate, 2002,14 (11), 845. Nanochromic films of this type are also described, for example, in U.S. Pat. Nos. 6,301,038, 6,870,657, and 6,950,220. This type of medium is also generally bistable. Another type of electro-optic display is the electro-wetting display developed by Philips and described in Hayes, R.A. et al, "Video-Speed Electronic Paper Based on Electrowetting", nature,425,383-385 (2003). It is shown in us patent 7,420,549 that such electrowetting displays can be made bistable. One type of electro-optic display that has been the subject of i