Security-enhanced display device

• US 6,650,306 B2
• Filed: 08/06/2001
• Issued: 11/18/2003
• Est. Priority Date: 08/06/2001
• Status: Expired due to Term

• Current Assignee: Mind Fusion, LLC (Ascend Innovation Management, LLC)
• Original Assignee: Mitsubishi Electric Research Laboratories, Inc. (Mitsubishi Electric Corporation)
• Inventors: Yerazunis, William S., Leigh, Darren L.
• Primary Examiner(s): Hjerpe, Richard
• Assistant Examiner(s): Dinh, Duc Q
• Application Number:
  US09/923,160
• Publication Number:
  US 20030025667A1
• Time in Patent Office: 834 Days
• Field of Search: 345/7-8, 345/102, 348/53-60, 359/460, 359/464, 359/501, 349/62, 349/64, 349/96, 349/99
• US Class Current: 345/8
• 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: G06F 21/84 output devices, e.g. displays or monitors

Abstract

A device for displaying images only to an authorized user includes a display device configured to display the images. The display device includes a backlight for generating incident light of mixed polarization, a first polarization rotator, and a first polarizer disposed between the backlight and the first polarization rotator. An optical shutter device is configured to view the displayed images. The optical shutter device includes a second polarization rotator and a second polarizer. The first and second polarization rotators are synchronously rotated while displaying the images so that the image are only perceived by the authorized user viewing the display device through the optical shutter device.

Claims

1. An apparatus for displaying images only to an authorized user, comprising:

a display device configured to display the images, the display device including a backlight for generating incident light of mixed polarization, a first polarization rotator, and a first polarizer disposed between the backlight and the first polarization rotator;

an optical shutter device configured to view the displayed images, the optical shutter device including a second polarization rotator and a second polarizer; and

means for synchronously rotating the first and second polarization rotators while displaying the images so that the images are only perceived by the authorized user viewing the display device through the optical shutter device.

2. The apparatus of claim 1 wherein the first and second polarization rotators are rotated periodically.

3. The apparatus of claim 1 wherein the first and second polarization rotators are rotated randomly.

4. The apparatus of claim 1 wherein the first and second polarization rotators are rotated on a pixel by pixel basis.

5. The apparatus of claim 1 wherein the rotating is performed by adding a ±

45°

off-set to a normal polarization modulation of the first and second rotators.

6. The apparatus of claim 1 wherein no images are perceived by an unauthorized user viewing the display device directly.

7. The apparatus of claim 1 wherein no images are perceived by an unauthorized user viewing the display device through stationary polarizers.