Dual panel display with cross BEF collimator and polarization-preserving diffuser

• US 9,329,430 B2
• Filed: 04/25/2012
• Issued: 05/03/2016
• Est. Priority Date: 04/28/2011
• 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, Giaretta, Giorgio, Kwong, Vincent
• Primary Examiner(s): Nguyen, Sang V
• Application Number:
  US14/113,896
• Publication Number:
  US 20140049734A1
• Time in Patent Office: 1,469 Days
• Field of Search: 349/74, 349/96
• US Class Current: 1/1
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133507 Films for enhancing the luminance
• CPC Class Codes: G02F 1/133536 Reflective polarizers G02F1/13362 takes precedence
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• 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 2340/06 Colour space transformation
• CPC Class Codes: G09G 3/3413 Details of control of colour illumination sources
• CPC Class Codes: G09G 3/3611 Control of matrices with row and column drivers

Abstract

A display including an image-generating panel and at least one contrast-enhancing panel, a cross BEF collimator between a backlight and one of the panels, and a polarization-preserving diffuser (e.g., holographic diffuser) between the panels. Typically, the contrast panel is upstream of the image panel, and a reflective polarizer is positioned between the cross BEF collimator or and contrast panel, with the reflective polarizer oriented relative to an initial polarizer of the contrast panel. Polarization of light transmitted by the reflective polarizer matches that transmitted by the initial polarizer. Collimated light propagating from the cross BEF collimator toward the contrast-enhancing panel is given a polarization bias by the reflective polarizer, which reflects incorrectly polarized light back toward the cross BEF collimator. Alternatively, the reflective polarizer may be positioned between the cross BEF collimator and the image-generating panel when the image-generating panel is upstream of the contrast-enhancing panel.

Claims

1. A dual panel display, comprising:

an image-generating panel;

at least one contrast-enhancing panel;

a backlight, positioned such that light from the backlight illuminates the the contrast-enhancing panel, and light transmitted through the contrast-enhancing panel illuminates the image-generating panel;

a controller, the controller receiving input image data and sending control signals to the backlight to emit a low resolution version of the input image data;

a polarization-preserving diffuser between the contrast-enhancing panel and the image-generating panel, said polarization-preserving diffuser comprising a holographic diffuser; and

a cross BEF collimator between the backlight and the contrast-enhancing panel;

a reflective polarizer between the backlight and the contrast-enhancing panel, wherein the backlight, the cross BEF collimator, the reflective polarizer, the contrast-enhancing panel, the polarization-preserving diffuser and the image-generating panel are arranged in this order.

2. The dual panel display of claim 1, wherein the contrast-enhancing panel is positioned between the backlight and the image-generating panel, the contrast-enhancing panel is configured to transmit modulated light having a specific polarization, and the polarization-preserving diffuser is configured and oriented to diffuse the modulated light while preserving the polarization of said modulated light.

3. The dual panel display of claim 2, also including the reflective polarizer oriented relative to the initial polarizer of the contrast-enhancing panel such that the polarization of light transmitted by the reflective polarizer matches that of the light transmitted by said initial polarizer.

4. The dual panel display of claim 3, wherein the reflective polarizer is a diffusing Dual Brightness Enhancement Film film.

5. The dual panel display of claim 3, wherein the reflective polarizer, the initial polarizer of the contrast-enhancing panel, the active layer of the contrast-enhancing panel, and the analyzing polarizer of the contrast-enhancing panel are laminated together, and the initial polarizer of the image-generating panel, the active layer of the image-generating panel, and the analyzing polarizer of the image-generating panel are laminated together.

6. The dual panel display of claim 1, wherein the image-generating panel is positioned between the backlight and the contrast-enhancing panel, the image-generating panel is configured to transmit modulated light having a specific polarization, and the polarization-preserving diffuser is configured and oriented to diffuse the modulated light while preserving the polarization of said modulated light.

7. The dual panel display of claim 6, also including a reflective polarizer positioned between the cross BEF collimator and the image-generating panel, with the reflective polarizer oriented relative to the initial polarizer of the image-generating panel such that the polarization of light transmitted by the reflective polarizer matches that of the light transmitted by said initial polarizer.

8. The dual panel display of claim 7, wherein the reflective polarizer is a diffusing Dual Brightness Enhancement Film film.

9. The dual panel display of claim 7, wherein the reflective polarizer, the initial polarizer of the image-generating panel, the active layer of the image-generating panel, and the analyzing polarizer of the image-generating panel are laminated together, and the initial polarizer of the contrast-enhancing panel, the active layer of the contrast-enhancing panel, and the analyzing polarizer of the contrast-enhancing panel are laminated together.

10. The dual panel display of claim 1, wherein said dual panel display comprises a dynamic range of greater than 800 to 1.

11. The dual panel display of claim 1, wherein said dual panel display is a dual LCD panel display, the image-generating panel is a color LCD panel, and the contrast-enhancing panel is an achromatic LCD panel.

12. The dual LCD panel display of claim 11, wherein the achromatic LCD panel is positioned between the backlight and the color LCD panel, the achromatic LCD panel is configured to transmit modulated light having a specific polarization, the polarization-preserving diffuser is configured and oriented to diffuse the modulated light while preserving the polarization of said modulated light, the color LCD panel is configured to modulate light having an input polarization, and the polarization of the modulated light transmitted by the achromatic LCD panel matches the input polarization of the color LCD panel.

13. The dual LCD panel display of claim 12, also including a reflective polarizer positioned between the cross BEF collimator and the achromatic LCD panel, with the reflective polarizer oriented relative to the initial polarizer of the achromatic LCD panel such that the polarization of light transmitted by the reflective polarizer matches that of the light transmitted by said initial polarizer.

14. The dual LCD panel display of claim 13, wherein the reflective polarizer is a diffusing Dual Brightness Enhancement Film film.

15. The dual LCD panel display of claim 13, wherein the reflective polarizer, the initial polarizer of the achromatic LCD panel, the active layer of the achromatic LCD panel, and the analyzing polarizer of the achromatic LCD panel are laminated together, and the initial polarizer of the color LCD panel, the active layer of the color LCD panel, and the analyzing polarizer of the color LCD panel are laminated together.

16. The dual LCD panel display of claim 11, wherein the color LCD panel is positioned between the backlight and the achromatic LCD panel, the color LCD panel is configured to transmit modulated light having a specific polarization, and the polarization-preserving diffuser is configured and oriented to diffuse the modulated light while preserving the polarization of said modulated light.

17. The dual LCD panel display of claim 16, also including a reflective polarizer positioned between the cross BEF collimator and the color LCD panel, with the reflective polarizer oriented relative to the initial polarizer of the color LCD panel such that the polarization of light transmitted by the reflective polarizer matches that of the light transmitted by said initial polarizer.

18. The dual LCD panel display of claim 17, wherein the reflective polarizer is a diffusing Dual Brightness Enhancement Film film.

19. The dual LCD panel display of claim 17, wherein the reflective polarizer, the initial polarizer of the color LCD panel, the active layer of the color LCD panel, and the analyzing polarizer of the color LCD panel are laminated together, and the initial polarizer of the achromatic LCD panel, the active layer of the achromatic LCD panel, and the analyzing polarizer of the achromatic LCD panel are laminated together.