DISPLAY THAT EMITS CIRCULARLY-POLARIZED LIGHT

• US 20100118235A1
• Filed: 01/19/2010
• Published: 05/13/2010
• Est. Priority Date: 08/08/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Yin, Victor H.E., Gettemy, Shawn R., Chen, Cheng, Zhong, John Z., Chen, Wei
• Granted Patent: US 7,911,565 B2
• Time in Patent Office: Days
• 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 computing device that includes:

a computational engine;

a memory-based storage system; and

a display used to present information;

wherein the display includes;

a display mechanism that emits linearly-polarized light;

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; and

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

2. The computing device of claim 1,

wherein the computing device is a portable computing device, which can be used outdoors or in other bright environments;

and

wherein the linearly-polarizing filter is a polarizing sunglass lens.

3. The computing device of claim 1,

wherein the layer comprises a retardation film;

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

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; and

wherein the thickness of the retardation film is tuned to convert linearly-polarized light to circularly-polarized light.

4. The computing device 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.

5. The computing device 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.

6. The computing device 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.