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

• US 9,864,243 B2
• Filed: 05/14/2010
• Issued: 01/09/2018
• Est. Priority Date: 05/14/2010
• Status: Active Grant

• Current Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Original Assignee: Dolby Laboratories Licensing Corporation (Dolby Laboratories Incorporated)
• Inventors: Erinjippurath, Gopal, Gilbert, John
• Primary Examiner(s): Glick, Edward
• Assistant Examiner(s): CHUNG, DAVID Y
• Application Number:
  US12/780,749
• Publication Number:
  US 20110279749A1
• Time in Patent Office: 2,797 Days
• Field of Search: 349 61- 65, 349 74- 83, 349112, 359599, 345690
• CPC Class Codes: G02F 1/133601 for spatial active dimming
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/13471 in which all the liquid crystal cells or layers remain transparent, e.g. FLC, ECB, DAP, HAN, TN, STN, SBE-LC cells G02F1/13475 takes precedence
• CPC Class Codes: G09G 2300/023 Display panel composed of stacked panels
• CPC Class Codes: G09G 2320/0646 Modulation of illumination source brightness and image signal correlated to each other
• CPC Class Codes: G09G 2360/16 Calculation or use of calculated indices related to luminance levels in display data
• CPC Class Codes: G09G 3/3426 the different display panel areas being distributed in two dimensions, e.g. matrix
• CPC Class Codes: H04N 13/324 Colour aspects
• CPC Class Codes: H04N 13/337 using polarisation multiplexing
• CPC Class Codes: H04N 13/351 for displaying simultaneously

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 (making them blacker or darker) using polarization rotation and filtration. Preferably, the second LCD panel is of higher resolution than the first LCD panel. The panels may be directly illuminated or edge lit, and may be globally or locally dimmed monochrome or multi primary lights that may also include individual control of color intensities for each image or frame displayed. The panels may be placed in any order, but preferably are arranged such that active layers in each panel are as close together as possible. Brightness is maintained by the combination of reusing polarization between the panels and by not going through more than one set of color filters. Improved contrast is a result of using multiple light modulators in series.

Claims

1. A display comprising,

a backlight, an image-generating panel, a contrast-improving panel, and a polarizer positioned between the image generating panel and the contrast improving panel, wherein the polarizer is operative as both an analyzing polarizer for the contrast-improving panel and an orientation polarizing layer for the image-generating panel and further wherein the image-generating panel comprises a color LCD panel that receives light from the backlight and transmits light to the contrast-improving panel that comprises a monochrome LCD panel wherein the resolution of the contrast-improving panel is greater than a resolution of the image-generating panel;

a mid-stream diffuser positioned between the contrast-improving panel and the image generating panel and having a diffusion resolution greater than the image-generating panel; and

a controller comprising an image-generating panel energization module and a contrast-improving panel energization module, the controller connected to energize both the image-generating panel and the contrast-improving panel with control data produced by the corresponding energization module,

wherein energization of the contrast-improving panel comprising;

extracting luminance values from an input image data received by the controller to produce a first intermediate data;

intentionally blurring the image apart from the point spread function of the backlight;

subpixel interpolating the first intermediate data to handle the difference between the resolution of the contrast-improvement panel and the image-generating panel to produce a second intermediate data; and

filtering the second intermediate data to produce a smoothed energizing data for the contrast-improving panel, the smoothed energizing data improving viewing angle performance and maintaining high frequency detail in the input image data;

wherein further energization of the image-generating panel is based in part on feedback from the contrast-improving panel energization module to the image-generation panel energization module.

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

3. The display according to claim 1, wherein the image-generating panel comprises a color-filter based LCD panel having a same polarization rotating design as the contrast-improving panel.

4. The display according to claim 1, wherein the contrast-improving panel is inverted relative to the image-generating panel such that active layers of the panels are closer together.

5. The display of claim 1 further wherein the intentional blurring of the image produces an illumination profile by using the higher resolution capabilities of the contrast-improving panel.

6. A display comprising,

a backlight, an image-generating panel, a contrast-improving panel, and a polarizer positioned between the image generating panel and the contrast improving panel, wherein the polarizer is operative as both an analyzing polarizer for the contrast-improving panel and an orientation polarizing layer for the image-generating panel and further wherein the image-generating panel comprises a color LCD panel that receives light from the backlight and transmits light to the contrast-improving panel that comprises a monochrome LCD panel;

a mid-stream diffuser positioned between the contrast-improving panel and the image generating panel and having a diffusion resolution greater than the image-generating panel; and

a controller comprising an image-generating panel energization module and a contrast-improving panel energization module, the controller connected to energize both the image-generating panel and the contrast-improving panel with control data produced by the corresponding energization module,

wherein the controller is configured to input data from a media source of a standardized high resolution, the image-generating panel is selected to be capable of producing an image of the standardized high resolution and the contrast-improving panel is configured to increase contrast using a resolution different than a resolution of the image generating panel;

wherein the resolution of the contrast-improving panel is greater than a resolution of the image-generating panel; and

wherein energization of the contrast-improving panel comprising;

extracting luminance values from the input data received by the controller to produce a first intermediate data;

producing an illumination profile that is intentionally blurred apart from the point spread function of the backlight;

subpixel interpolating the first intermediate data to handle the difference between the resolution of the contrast-improvement panel and the image-generating panel to produce a second intermediate data; and

filtering the second intermediate data to produce a smoothed energizing data for the contrast-improving panel, the smoothed energizing data improving viewing angle performance and maintaining high frequency detail in the input data.

7. The display according to claim 6, wherein the contrast improving panel is backlight by at least one edge lit array of light sources.

8. A display comprising,

a backlight, an image-generating panel, a contrast-improving panel, and a polarizer positioned between the image generating panel and the contrast improving panel and further wherein the image-generating panel comprises a color LCD panel that receives light from the backlight and transmits light to the contrast-improving panel that comprises a monochrome LCD panel wherein the resolution of the contrast-improving panel is greater than a resolution of the image-generating panel;

wherein the image generating layer is backlight by at least one edge lit array of light sources, and

the display further comprising a contrast layer diffuser having a resolution that differs from the contrast improving panel and a controller configured to receive input image data and send control signals to energize the contrast-improving panel and the image-generating panel; and

wherein further energization of the contrast-improving panel comprising;

extracting luminance values from the input image data to produce a first intermediate data;

producing an illumination profile that is intentionally blurred apart from the point spread function of the backlight;

subpixel interpolating the first intermediate data to handle the difference between the resolution of the contrast-improvement panel and the image-generating panel to produce a second intermediate data; and

filtering the second intermediate data to produce a smoothed energizing data for the contrast-improving panel, the smoothed energizing data improving viewing angle performance and maintaining high frequency detail in the input image data.

9. A display comprising,

a backlight, an image-generating panel, a contrast-improving panel, and a polarizer positioned between the image generating panel and the contrast improving panel, wherein light from the backlight illuminates the image-generating panel that modulates the intensity and color of the light which illuminates the contrast-improving panel, the contrast-improving panel comprising a controllable polarizer and further wherein the image-generating panel comprises a color LCD panel and the contrast-improving panel that comprises a monochrome LCD panel wherein the resolution of the contrast-improving panel is greater than a resolution of the image-generating panel;

an upstream diffuser and a downstream diffuser, wherein the upstream diffuser has a relatively coarse diffusion resolution and is configured to diffuse a backlight configured to illuminate the upstream panel and the downstream diffuser has a relatively fine diffusion resolution configured to mask at least one of high frequency details and uncontrolled features of the upstream panel;

a controller configured to receive input image data and send control signals to energize the contrast-improving panel and the image-generating panel; and

wherein further energization of the contrast-improving panel comprising;

extracting luminance values from the input image data to produce a first intermediate data;

producing an illumination profile that is intentionally blurred apart from the point spread function of the backlight;

subpixel interpolating the first intermediate data to handle the difference between the resolution of the contrast-improvement panel and the image-generating panel to produce a second intermediate data; and

filtering the second intermediate data to produce a smoothed energizing data for the contrast-improving panel, the smoothed energizing data improving viewing angle performance and maintaining high frequency detail in the input image data.

10. A display comprising,

a backlight, an image-generating panel, a contrast-improving panel, and a polarizer positioned between the image generating panel and the contrast improving panel, wherein light from the backlight illuminates the image-generating panel that modulates the intensity and color of the light which illuminates the contrast-improving panel, the contrast-improving panel comprising a controllable polarizer and further wherein the image-generating panel comprises a color LCD panel and the contrast-improving panel that comprises a monochrome LCD panel wherein the resolution of the contrast-improving panel is greater than a resolution of the image-generating panel and wherein the contrast-improving panel intentionally blurs the image apart from the point spread function of the backlight;

a midstream diffuser that does not substantially alter the polarization of light being diffused and which has a diffusion resolution greater than a resolution of the upstream panel; and

an array of locally dimmed light sources,

wherein the image-producing panel produces a base version of an image to be displayed by the display and the contrast-improving panel further modulates the base image to produce the image to be displayed,

wherein the base image comprises a brightness intensity in a proportion to brightness intensities of the image to be displayed, and

wherein the base image comprises a subpixel interpolation to handle the difference between the resolution of the contrast-improvement panel and the image-generating panel to produce a second intermediate data; and

a filtering to improve the viewing angle performance and maintain high frequency detail in the input image data.

11. The display of claim 10 further wherein the intentional blurring of the image produces an illumination profile by using the higher resolution capabilities of the contrast-improving panel.

12. A modulator comprising,

an upstream modulating panel, a downstream modulating panel, and an analyzing-orienting layer between the panels operative as an analyzer with respect to the upstream modulating panel and as an orientation layer with respect to the downstream modulating panel, wherein the upstream modulating panel comprises an image-generating panel that modulates light by intensity and color and the downstream modulating panel comprises a contrast-improving panel, the contrast-improving panel comprising a controllable polarizer and further wherein the image-generating panel comprises a color LCD panel and the contrast-improving panel that comprises a monochrome LCD panel wherein the resolution of the contrast-improving panel is greater than a resolution of the image-generating panel;

a diffusing element positioned between the panels wherein the diffuser has a diffusing resolution of less than a modulating resolution of the upstream panel wherein the upstream panel is inverted relative to the downstream panel;

a controller configured to receive input image data and send control signals to energize the contrast-improving panel and the image-generating panel; and

wherein further energization of the contrast-improving panel comprising;

extracting luminance values from the input image data to produce a first intermediate data;

producing an illumination profile that is intentionally blurred apart from the point spread function of the backlight;

subpixel interpolating the first intermediate data to handle the difference between the resolution of the contrast-improvement panel and the image-generating panel to produce a second intermediate data; and

filtering the second intermediate data to produce a smoothed energizing data for the contrast-improving panel, the smoothed energizing data improving viewing angle performance and maintaining high frequency detail in the input image data.

13. A modulator comprising,

an upstream modulating panel, a downstream modulating panel, and an analyzing-orienting layer between the panels operative as an analyzer with respect to the upstream modulating panel and as an orientation layer with respect to the downstream modulating panel, wherein the upstream modulating panel comprises an image-generating panel that modulates light by intensity and color and the downstream modulating panel comprises a contrast-improving panel, the contrast-improving panel comprising a controllable polarizer and further wherein the image-generating panel comprises a color LCD panel and the contrast-improving panel that comprises a monochrome LCD panel wherein the resolution of the contrast-improving panel is greater than a resolution of the image-generating panel;

a diffusing element configured so as to not substantially alter polarization of light being diffused and which is positioned between the panels wherein the diffusing element has a diffusing resolution of less than a modulating resolution of the upstream panel;

a controller configured to receive input image data and send control signals to energize the contrast-improving panel and the image-generating panel; and

wherein further energization of the contrast-improving panel comprising;

extracting luminance values from the input image data to produce a first intermediate data;

producing an illumination profile that is intentionally blurred apart from the point spread function of the backlight;

subpixel interpolating the first intermediate data to handle the difference between the resolution of the contrast-improvement panel and the image-generating panel to produce a second intermediate data; and

filtering the second intermediate data to produce a smoothed energizing data for the contrast-improving panel, the smoothed energizing data improving viewing angle performance and maintaining high frequency detail in the input image data.

14. The modulator according to claim 13, wherein the panels each include an active layer and the panels are oriented such that the active layers are as close together as possible.

15. A display comprising,

a pair of LCD panels in a light path each comprising a plurality of layers, wherein a first of the LCD panels is oriented differently than a second of the LCD panels wherein the orientation brings active layers of the panels closer together;

wherein the first of the LCD panels comprises an upstream modulating panel and further comprises an image-generating panel that modulates light by intensity and color and the second of the LCD panels comprises a downstream modulating panel and further comprises a contrast-improving panel, the contrast-improving panel comprising a controllable polarizer and further wherein the image-generating panel comprises a color LCD panel and the contrast-improving panel that comprises a monochrome LCD panel wherein the resolution of the contrast-improving panel is greater than a resolution of the image-generating panel;

further comprising a high frequency diffuser between the LCD panels, wherein the high frequency diffuser is a diffuser configured to diffuse light at a resolution higher than a resolution of the first panel;

a controller configured to receive input image data and send control signals to energize the contrast-improving panel and the image-generating panel; and

wherein further energization of the contrast-improving panel comprising;

extracting luminance values from the input image data to produce a first intermediate data;

producing an illumination profile that is intentionally blurred apart from the point spread function of the backlight;

subpixel interpolating the first intermediate data to handle the difference between the resolution of the contrast-improvement panel and the image-generating panel to produce a second intermediate data; and

filtering the second intermediate data to produce a smoothed energizing data for the contrast-improving panel, the smoothed energizing data improving viewing angle performance and maintaining high frequency detail in the input image data.

16. The modulator according to claim 15, wherein the LCD panels are illuminated by a locally dimmed backlight.