Display device

• US 7,576,915 B2
• Filed: 11/24/2004
• Issued: 08/18/2009
• Est. Priority Date: 12/17/2003
• Status: Expired due to Fees

• Current Assignee: Innolux Hong Kong Holding Ltd (InnoLux Corporation)
• Original Assignee: Koninklijke Philips Electronics N.V. (Koninklijke Philips N.V.)
• Inventors: Kurt, Ralph
• Primary Examiner(s): Ward; John A
• Application Number:
  US10/596,446
• Publication Number:
  US 20080285135A1
• Time in Patent Office: 1,728 Days
• Field of Search: 362615-619, 359 40- 42, 359/599, 359/620, 359/626
• US Class Current: 359/599
• CPC Class Codes: G02B 6/08 with fibre bundle in form of plate
• CPC Class Codes: G02F 1/133502 Antiglare, refractive index matching layers
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133524 Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
• CPC Class Codes: H01J 2329/892 Anti-reflection, anti-glare, viewing angle and contrast improving means
• CPC Class Codes: H01J 29/89 Optical or photographic arrangements structurally combined or co-operating with the vessel H01J29/866 and H01J29/868 take precedence
• CPC Class Codes: H01J 29/892 using fibre optics

Abstract

A display device comprises a light emitting picture element (120) and a contrast enhancing element (110). The contrast enhancing element comprises a plurality of wave guides (216) separated by interstitial regions (212) being formed as narrowing recesses. An interface between a wave guide (216) and an interstitial region (212) is provided with a reflective layer. The narrowing recesses form a dead end for incident ambient light which is efficiently absorbed by the contrast enhancing element. On the other hand, light emitted by the picture element (120) of the display device is transmitted through the wave guides (216). As a result, the display device has a relatively high contrast ratio, particularly under bright ambient light conditions.

Claims

1. A display device (100), comprising:

a light emitting picture element (120); and

a contrast enhancing element (110), the contrast enhancing element comprising a substrate having a plurality of wave guides (216), the wave guides including a first material of a first refractive, index adjacent said picture element (120), and interstitial regions (212) including a second material of a lower refractive index than the first refractive index, the interstitial regions (212) being arranged between the wave guides (216) and formed narrowing in the direction of the picture, element; and

a reflective layer (214) provided on an interface between a wave guide (216) and an interstitial region (212), wherein the reflective layer is configured to reflect ambient light entering the interstitial regions between the wave guides;

wherein a cross-section length of an exit surface of a wave guide is in the order of magnitude of a wavelength of light in the visible range.

2. The display device of claim 1, wherein the interstitial regions (212) have a tapered shape.

3. The display device of claim 1, wherein an entrance plane (217) of the plurality of wave guides (216) is arranged for receiving light emitted from said element, a surface area of an exit plane (218) of said plurality of wave guides (216) being substantially smaller than a surface area of said entrance plane.

4. The display device of claim 1, wherein said reflective layer is a metal layer.

5. The display device of claim 1, wherein the interstitial regions are substantially funnel-shaped.

6. The display device of claim 1, wherein the top angle of an interstitial region (212) has a top angle (2a) of less than 90 degrees.

7. The display device of claim 6, wherein the top angle lies between 30 and 60 degrees.

8. The display device of claim 1, wherein a thickness of the wave guide substrate is between 100 nanometers and 10 micrometers.

9. The display device of claim 1, wherein the plurality of wave guides and/or the interstitial regions are arranged in a random structure.

10. The display device of claim 1, wherein the display device comprises one of a polymer light emitting display, organic light emitting display, transmissive liquid crystal display, cathode ray tube, plasma display or field emission display.