Electrophoretic Device Having a Transparent Light State

Patent metadata

Field	Value
Publication number	US-2021072578-A1
Application number	US-202017084823-A
Country	US
Kind code	A1
Filing date	Oct 30, 2020
Priority date	Mar 22, 2013
Publication date	Mar 11, 2021
Grant date	—

Abstract

A light attenuator comprises a cell comprising a first substrate and a second substrate spaced apart from the first substrate. A layer between the substrates contains an electrophoretic ink, a surface of the layer adjacent the second substrate comprising a monolayer of closely packed protrusions projecting into the layer. The protrusions have surfaces defining a plurality of depressions in the volumes there between. The ink includes charged particles of at least one type, the particles being responsive to an electric field applied to the cell to move between a first extreme light state, in which particles are maximally spread within the cell to lie in the path of light through the cell and to strongly attenuate light transmitted through the cell; over the surface of the protrusions, which deflect the particles from their path from the first substrate to the second substrate; to a second extreme light state in which the particles are maximally concentrated within the depressions to remove them from the path of light through the cell and to substantially transmit light through the cell.

First claim

1 . An electrophoretic device comprising:
a cell comprising a first substrate and a second substrate spaced apart from said first substrate; a layer comprising an electrophoretic ink disposed between said first substrate and said second substrate, the layer including charged particles of at least one type, the particles being responsive to an electric field applied thereto; a non-planar polymer structure adjacent the second substrate including light-masking walls, said light-masking walls contacting said first substrate through a light-masking adhesive layer, the non-planar polymer structure additionally including protrusions, said protrusions having surfaces defining a plurality of depressions in a volume of the layer comprising an electrophoretic ink disposed between said first substrate and said second substrate, said protrusions projecting into said layer, wherein the electrophoretic device includes a first extreme light state, in which particles are maximally spread within the cell to lie in the path of light travelling into the cell and to strongly attenuate light entering or transmitted through the cell; and a second extreme light state in which said particles are maximally concentrated within said depressions to remove the particles from the path of light into the cell and to reflect or substantially transmit light through the cell.

2 . The electrophoretic device of claim 1 , wherein said light-masking adhesive is printed on a contact area of said light-masking walls, and where contact area is less than 25% of said electrophoretic device's face-area.

3 . The electrophoretic device of claim 1 , wherein said light-masking adhesive comprises black colorant.

4 . The electrophoretic device of claim 3 , wherein said light-masking adhesive layer comprises a black polymer layer and an adhesive.

5 . The electrophoretic device of claim 1 , wherein said light-masking walls define a space between said protrusions and said first substrate.

6 . The electrophoretic device of claim 1 , wherein said protrusions are transparent to visible light.

7 . The electrophoretic device of claim 6 , further comprising a first transparent electrode adjacent the first substrate and a second transparent electrode adjacent the second substrate.

8 . The electrophoretic device of claim 1 , further comprising a first transparent electrode adjacent the first substrate.

9 . The electrophoretic device of claim 8 , further comprising a second transparent electrode adjacent the first substrate.

10 . The electrophoretic device of claim 1 , further comprising a first transparent electrode adjacent the second substrate.

Assignees

• E Ink Corp

Inventors

• O'Keeffe Donal

Classifications

• G02F1/167 Primary

  by electrophoresis · CPC title

• G02F1/13306 Primary

  Circuit arrangements or driving methods for the control of single liquid crystal cells (G02F1/132, G02F1/133382 take precedence) · CPC title

• G02F1/1679

  Gaskets; Spacers; Sealing of cells; Filling or closing of cells · CPC title

• G02F1/13396

  Spacers having different sizes · CPC title

• G02F1/13394

  spacers regularly patterned on the cell subtrate, e.g. walls, pillars (G02F1/133377 takes precedence) · CPC title