Display that emits circularly-polarized light

• US 7,683,983 B2
• Filed: 08/08/2006
• Issued: 03/23/2010
• Est. Priority Date: 08/08/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Gettemy, Shawn R., Chen, Cheng, Zhong, John Z., Chen, Wei, Yin, Victor H. E.
• Primary Examiner(s): Pak; Sung H
• Application Number:
  US11/500,677
• Publication Number:
  US 20080036948A1
• Time in Patent Office: 1,323 Days
• Field of Search: None
• US Class Current: 349/98
• CPC Class Codes: G02F 1/13363 Birefringent elements, e.g. for optical compensation
• CPC Class Codes: G02F 1/133638 Waveplates, i.e. plates with a retardation value of lambda/n
• CPC Class Codes: G02F 2413/03 Number of plates being 3
• CPC Class Codes: G02F 2413/06 Two plates on one side of the LC cell

Abstract

One embodiment of the present invention provides a display that emits circularly-polarized light. This display includes a display mechanism that emits linearly-polarized light and a layer placed in the path of the linearly-polarized light. The layer receives the linearly-polarized light on one surface, converts the linearly-polarized light to circularly-polarized light, and then emits the circularly-polarized light from another surface. By emitting circularly-polarized light, the display reduces the perceived distortion found at some angles when the display is viewed through a linearly-polarizing filter.

Claims

1. A display that emits circularly-polarized light, comprising:

a display mechanism that emits linearly-polarized light; and

a layer that circularly polarizes light which is placed in the path of the linearly-polarized light, so that the layer converts the linearly-polarized light to circularly-polarized light;

one or more a-plates coupled to the layer that circularly polarizes light;

wherein the display reduces perceived distortion when the display is viewed through a linearly-polarizing filter.

2. The display of claim 1, wherein the linearly-polarizing filter is a polarizing sunglass lens.

3. The display of claim 1,

wherein the layer comprises a retardation film;

and

wherein the retardation film has a higher refractive index in a first direction than in a second direction perpendicular to the first direction.

4. The display of claim 3, wherein the first direction in the retardation film is aligned 45 degrees with respect to the plane of the linearly-polarized light emitted by the display mechanism.

5. The display of claim 3, wherein the thickness of the retardation film is tuned to convert linearly-polarized light to circularly-polarized light.

6. The display of claim 1, wherein the layer is:

laminated on top of the display mechanism;

a film in front of the display mechanism; and

/or

incorporated into a display cover which can be attached to the display mechanism.

7. The display of claim 1, wherein the display mechanism includes:

a transmissive mechanism configured to actively generate and transmit light;

a reflective mechanism configured to selectively reflect external light;

or

a trans-flective mechanism configured to both actively generate and transmit light as well as selectively reflect external light.

8. The display of claim 1, wherein the display mechanism is a liquid crystal display mechanism that further comprises:

a liquid crystal layer; and

a polarizing layer that linearly polarizes light.