Method and apparatus for improved color filter saturation
View Patent ↗A reflective image display comprising of a reflection enhancing layer comprising of a plurality of approximately spherical indentations is placed adjacent a sheet comprising of a plurality of hemispherical protrusions. The radii of curvature of the spherical indentations substantially coincides with the center of curvature of the adjacently located hemispheres to enhance the white paper-like appearance of the display while efficiently enabling optional color filters to yield saturated color.
1. A totally internally reflective display with a brightness enhancing structure, the display comprising:
a first optically transparent sheet;
at least one electrode layer;
a second optically transparent sheet having a surface further comprising of a plurality of convex or hemi-spherical protrusions, each of the convex or hemi-spherical protrusions having a dark pupil region;
a reflection enhancing layer that substantially semi-retro-reflects an incoming ray of light that passes through the dark pupil regions of the convex or hemi-spherical protrusions;
at least one optical modulation layer wherein light is prevented or allowed to pass, the optical modulation layer including a cavity having one or more electrophoretic particles suspended in a medium; and
a voltage source to controllably modulate the optical layer;
wherein the outgoing light ray is substantially parallel to the incoming light ray.
2. A reflective display according to claim 1 , wherein the voltage source is switchable to:
apply a voltage across the optical modulation layer of one polarity to allow light to pass; and
apply a voltage across the optical modulation layer of a second polarity to prevent light from passing.
3. The reflective display according to claim 2 , wherein the reflection enhancing layer comprises an array of approximately spherical indentations, whereby each spherical indentation further comprises a radius of curvature that substantially coincides with the center of curvature of the convex or hemi-spherical protrusion located substantially above the array of approximately spherical indentations.
4. The reflective display according to claim 3 , wherein the ratio of the radius of curvature of a spherical indentation to the radius of curvature of a hemi-spherical protrusion is about 0.5 to 5.
5. The reflective display according to claim 3 , wherein the ratio of the radius of curvature of a spherical indentation to the radius of curvature of a hemi-spherical protrusion is about 1 to 3.
6. The reflective display according to claim 3 , wherein the ratio of the radius of curvature of a spherical indentation to the radius of curvature of a hemi-spherical protrusion is about 1 to 2.
7. The reflective display according to claim 3 , wherein the optical modulating layer is comprised of an electrophoretic medium further comprised of a plurality of suspended electrostatically charged light absorbing electrophoretically mobile particles.
8. The reflective display according to claim 3 , wherein the optical modulating layer is comprised of an electro-wetting system.
9. The reflective display according to claim 3 , wherein the optical modulating layer is comprised of a micro-electromechanical system.
10. The reflective display according to claim 7 , wherein:
movement of the electrophoretically mobile particles by application of a voltage of one polarity creates a light state; and
movement of the electrophoretically mobile particles by application of a voltage of a second polarity creates a dark state.
11. The reflective display according to claim 1 , further comprising a color filter array comprised of red, green and blue sub-pixels.
12. The reflective display according to claim 1 , further comprising a color filter array comprised of cyan, magenta and yellow sub-pixels.
13. The reflective display according to claim 1 , wherein at least one electrode layer comprises a thin film transistor array.
14. The reflective display according to claim 1 , wherein at least one electrode layer comprises a patterned array.
15. The reflective display according to claim 1 , further comprising spacers or spacer beads.
16. The reflective display according to claim 7 , wherein the electrophoretically mobile particles are comprised of an organic material or an inorganic material or a combination of an inorganic and organic material.
17. The reflective display according to claim 7 , wherein the electrophoresis medium is comprised of a hydrocarbon or a fluorocarbon or a combination of a hydrocarbon and fluorocarbon.
18. The reflective display according to claim 1 , wherein the optically transparent sheet having a surface comprising of a plurality of convex protrusions or hemi-spherical protrusions may be formed by any one of embossing, etching, molding, self-assembly, printing, lithography or micro-replication.
19. The reflective display according to claim 3 , wherein the reflection enhancing layer comprised of a plurality of spherical indentations may be formed by any one of embossing, etching, molding, self-assembly, printing, lithography or micro-replication.
20. The reflective display according to claim 1 , further comprising a front light.
21. An electronic book reader, portable computer, tablet computer, wearable, cellular telephone, smart card, sign, watch, shelf label, flash drive, outdoor billboards or outdoor signs comprising a display according to claim 1 .