Electrophoretic display apparatus switchable between black-white mode and color mode

Patent metadata

Field	Value
Publication number	US-9019199-B2
Application number	US-201213669465-A
Country	US
Kind code	B2
Filing date	Nov 6, 2012
Priority date	Apr 3, 2012
Publication date	Apr 28, 2015
Grant date	Apr 28, 2015

Abstract

Disclosed herein is an electrophoretic display apparatus switchable between a black-white mode and a color mode. The electrophoretic display apparatus includes an electrophoretic display panel, a light guide, a light source, a light-splitting element and a lens element. The light guide is disposed in front of a display area of the electrophoretic display panel. The light source is operable to emit a light, which is directed to the display area by the light guide. The light-splitting element is disposed between the light guide and the electrophoretic display panel, and is operable to split the light into a first, a second and a third beam each having a principal wavelength different from the others. The lens element is disposed between the light-splitting element and the display area, and is operable to direct the first, second and third beams to corresponding sub-pixels.

First claim

What is claimed is:

1. An electrophoretic display apparatus switchable between a black-white mode and a color mode, the electrophoretic display apparatus comprising:
an electrophoretic display panel having a display area, the display area comprising a first sub-pixel, a second sub-pixel and a third sub-pixel;
a light guide positioned over the display area, wherein the light guide has a light receiving surface and a light emitting surface that faces the display area;
a light source for emitting a light into the light receiving surface, wherein the light guide is operable to direct the light towards the display area through the light emitting surface;
a light-splitting element interposed between the light guide and the electrophoretic display panel, and capable of splitting the light directed towards the display area into a first light beam, a second light beam and a third light beam each having a wavelength different from one another, wherein the first light beam, the second light beam and the third light beam are transmitted in different directions; and
a lens element for directing the first light beam, the second light beam and the third light beam to the first sub-pixel, the second sub-pixel and the third sub-pixel, respectively, the lens element being disposed between the light-splitting element and the electrophoretic display panel, wherein the lens element has a first surface facing the light-splitting element, and a second surface opposite to the first surface, and the lens element comprises:
a plurality of first cylindrical lenses formed in parallel with each other on the first surface;
a plurality of second cylindrical lenses formed in parallel with each other on the second surface; and
a plurality of third cylindrical lenses formed in parallel with each other on the second surface, wherein the third cylindrical lenses are parallel with the second cylindrical lenses, and each of the second cylindrical lenses and each of the third cylindrical lenses are alternately arranged, wherein each of the second cylindrical lenses has a thickness that is greater than a thickness of each of the third cylindrical lenses;

wherein when the light source is turned on, the electrophoretic display apparatus is operated in the color mode, and
when the light source is turned off, the electrophoretic display apparatus is operated in the black-white mode.

2. The electrophoretic display apparatus according to claim 1 , wherein the light-splitting element comprises a plurality of triangular prisms each having a crest line, and the crest lines are arranged in parallel with each other.

3. The electrophoretic display apparatus according to claim 1 , wherein the light-splitting element comprises a diffraction grating that is in contact with the light emitting surface.

4. The electrophoretic display apparatus according to claim 1 , wherein each of the first cylindrical lenses adjoins another one of the first cylindrical lenses, and each of the second cylindrical lenses adjoins one of the third cylindrical lenses.

5. The electrophoretic display apparatus according to claim 4 , wherein each of the first cylindrical lenses has a width greater than a width of each of the second cylindrical lenses, and each of the second cylindrical lenses is arranged at a position opposite to a common adjoining edge between two adjoined first cylindrical lenses.

6. The electrophoretic display apparatus according to claim 1 , wherein each of the first cylindrical lenses has a radius of curvature greater than a radius of curvature of each of the second cylindrical lenses.

7. The electrophoretic display apparatus according to claim 1 , wherein each of the second cylindrical lenses has a radius of curvature that is different from a radius of curvature of each of the third cylindrical lenses.

8. The electrophoretic display apparatus according to claim 1 , wherein the lens element is an aspherical lens array.

9. The electrophoretic display apparatus according to claim 1 , further comprises a lens disposed between the light source and the light receiving surface.

10. The electrophoretic display apparatus according to claim 1 , wherein the light-splitting element comprises:
a first refraction grating array having a plurality of first prisms, wherein each of the first prisms has a first crest line parallel with a first direction, and each first crest line is separated from an adjacent first crest line by a first pitch distance; and
a second refraction grating array having a plurality of second prisms, wherein each of the second prisms has a second crest line parallel with a second direction, and each second crest line is separated from an adjacent second crest line by a second pitch distance;
wherein the first refraction grating array and the second refraction grating array are spaced apart by a spacing, and the first direction is not parallel with the second direction.

11. The electrophoretic display apparatus according to claim 10 , wherein the first pitch distance is not equal to the second pitch distance.

Assignees

• E Ink Holdings Inc

Inventors

• Wang Shih-Yu

Classifications

• G02F1/167 Primary

  by electrophoresis · CPC title

• G02F1/133616

  Front illuminating devices · CPC title

• G02F2203/34

  Colour display without the use of colour mosaic filters · CPC title

• G02F2201/305

  diffraction grating · CPC title

• G02F1/1677

  Structural association of cells with optical devices, e.g. reflectors or illuminating devices · CPC title