High dynamic range displays using filterless LCD(s) for increasing contrast and resolution

Patent metadata

Field	Value
Publication number	US-9772530-B2
Application number	US-201213472076-A
Country	US
Kind code	B2
Filing date	May 15, 2012
Priority date	May 14, 2010
Publication date	Sep 26, 2017
Grant date	Sep 26, 2017

Abstract

A display provides increased contrast and resolution via first LCD panel energized to generate an image and a second LCD panel configured to increase contrast of the image. The second panel is an LCD panel without color filters and is configured to increase contrast by decreasing black levels of dark portions of images using polarization rotation and filtration. The second LCD panel may have higher resolution than the first LCD panel. A half wave plate and/or film is placed in between the first and the second panel. The panels may be directly illuminated or edge lit, and may be globally or locally dimmed lights that may also include individual control of color intensities for each image or frame displayed.

First claim

What is claimed and desired to be secured by Letters Patent of the United States is:

1. A display comprising:
a backlight;
an upstream diffuser, the upstream diffuser smoothing the light from the backlight;
an image-generating panel, the image-generating panel comprising a color LCD panel wherein the image-generating panel receives light from the backlight and produces a color image;
a contrast-improving panel, the contrast-improving panel comprising a monochrome LCD panel wherein the contrast-improving panel receives light from the image-generating panel and wherein further the contrast-improving panel comprises a lower resolution than the image-generating panel;
a half wave plate positioned between the image generating panel and the contrast improving panel; and
a polarizing preserving diffuser positioned between the image generating panel and the contrast improving panel, further wherein said polarizing preserving diffuser providing smooth variance of lighting within substantially a single pixel;
wherein the upstream diffuser is configured to mix light such that a single pixel of the upstream diffuser is substantially illuminated by a plurality of light sources in the backlight and the polarizing preserving diffuser is configured to mix light on a sub-pixel level to substantially mask high frequency details in the light from the image-generating panel onto the contrast-improving panel; and
a controller, the controller configured to:
receive input image data;
generate a polarization control signal from the input image data;
send the polarization control signal to the contrast-improving panel;
generate a color control signal for the image-generating panel, the color control signal generated from both the input image data and the polarization control signal; and
sending the color control signal to the image-generating panel.

2. The display according to claim 1 , wherein the resolution of the contrast-improving panel is the same as the resolution of the image-generating panel.

3. The display according to claim 1 , wherein the resolution of the contrast-improving panel is higher than the resolution of the image-generating panel.

4. The display according to claim 1 , wherein the resolution of the contrast-improving panel is lower than the resolution of the image-generating panel.

5. The display according to claim 1 , wherein the backlight comprises a direct lit backlight.

6. The display according to claim 1 wherein the backlight comprises an edge-lit backlight.

7. The display according to claim 1 wherein the backlight may comprise individually controllable light sources.

8. The display according to claim 7 wherein said light source may be controlled with respect to brightness.

9. The display according to claim 1 wherein said polarization-preserving diffuser is upstream of said half-wave plate.

10. The display according to claim 1 wherein said polarization-preserving diffuser is downstream of said half-wave plate.

11. The display according to claim 1 wherein said polarization-preserving diffuser is combined with said half-wave plate.

12. The display according to claim 1 wherein said image-generating panel is one of a group, said group comprising: a color panel and a greyscale panel.

13. The display according to claim 1 wherein said contrast-improving panel is one of a group, said group comprising: a color panel and a greyscale panel.

14. The display according to claim 1 wherein said polarization-preserving diffuser comprises a diffuser that substantially eliminates the visual moire between said image-generating panel and said contrast-improving panel.

15. The display according to claim 1 wherein said polarization-preserving diffuser comprises a diffuser that substantially minimizes the birefringence interaction with the polarization direction.

16. A display comprising:
a backlight;
an upstream diffuser, the upstream diffuser smoothing the light from the backlight;
a first stack structure, said first stack structure comprising:
a reflecting polarizer;
an initial polarizer;
a color LCD panel;
a finishing polarizer;
a half wave plate; and
a polarization-preserving polarizer, wherein said polarizing preserving diffuser providing smooth variance of lighting within substantially a single pixel; and

a second stack structure, said second stack structure further comprising:
an initial polarizer;
a monochrome LCD panel, the monochrome LCD panel comprising a lower resolution than the color LCD panel;
a finishing polarizer;

wherein the upstream diffuser is configured to mix light such that a single pixel of the upstream diffuser is substantially illuminated by a plurality of light sources in the backlight and the polarizing preserving diffuser is configured to mix light on a sub-pixel level to substantially mask high frequency details in the light from the first stack structure onto the second stack structure; and
a controller, the controller configured to:
receive input image data;
generate a polarization control signal from the input image data;
send the polarization control signal to the contrast-improving panel;
generate a color control signal for the image-generating panel, the color control signal generated from both the input image data and the polarization control signal; and
sending the color control signal to the image-generating panel.

17. The display according to claim 16 wherein said half wave plate affect a polarization of the image which is compatible with the initial polarizer of the second stack structure.

Assignees

• Gilbert John
• Dolby Laboratories Licensing Corp

Inventors

• Gilbert John

Classifications

• G09G2300/023

  Display panel composed of stacked panels · CPC title

• G09G2360/16

  Calculation or use of calculated indices related to luminance levels in display data · CPC title

• G09G3/3426

  the different display panel areas being distributed in two dimensions, e.g. matrix · CPC title

• G02F1/133606

  including a specially adapted diffusing, scattering or light controlling members · CPC title

• H04N13/0422

  Electricity · mapped topic