Polarization plate for use in a liquid crystal display

• US 9,285,523 B2
• Filed: 06/25/2014
• Issued: 03/15/2016
• Est. Priority Date: 03/21/2007
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Lamberth, L. S. Jr., Laddu, Ravindra R., Larson, Brent D.
• Primary Examiner(s): Vu, Phu
• Application Number:
  US14/314,258
• Publication Number:
  US 20140307202A1
• Time in Patent Office: 629 Days
• US Class Current: 1/1
• CPC Class Codes: G02B 5/3033 in the form of a thin sheet or foil, e.g. Polaroid
• CPC Class Codes: G02B 5/3083 Birefringent or phase retarding elements G02B5/3008, G02B5/3016 take precedence; systems for polarisation control G02B27/286; manufacturing phase modulating patterns by lithographic processes G03F7/001
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one
• CPC Class Codes: G02F 2201/54 Arrangements for reducing warping-twist

Abstract

A polarization plate is provided for use between a light source and a display panel, where the light source is configured to emit light having a plurality of planes of polarization and the display panel is configured to have a predetermined polarization axis. The plate includes a repolarization region and a prepolarization region. The repolarization region is configured to diffuse and to depolarize or rotate at least one plane of polarization of the light passing therethrough. The prepolarization region is disposed adjacent to and in contact with the repolarization region. The prepolarization region is configured to be substantially nonabsorbent, to allow passage of light having a plane of polarization that is substantially aligned with the predetermined polarization axis, and to prevent passage of light having a plane of polarization that is not substantially aligned with the predetermined polarization axis. In another embodiment, an interface is provided between the regions.

Claims

1. A component for use between a light source and a display panel of a liquid crystal display, the component comprising:

a plate comprising a first layer and a second layer, the plate including a first major surface, a second major surface opposing the first major surface, and an edge joining the first and second major surfaces, the first major surface configured to allow a majority of incident light from a light source to be transmitted therethrough and defining a first side of the first layer, the second major surface configured to receive a portion of the transmitted incident light from the first layer and defining a first side of the second layer,

wherein;

the first layer has a microscopically varying refraction index, the first layer adapted to diffusely backscatter a portion of incident light entering the first layer and to depolarize a plane of polarization of the portion of incident light passing through the first layer,

the second layer is configured to be substantially index-matched to the first layer and substantially nonabsorbent to allow passage of light through the second major surface having a plane of polarization that is substantially aligned with a predetermined polarization axis of the display panel, and to substantially prevent passage of light through the second major surface having a plane of polarization that is not substantially aligned with the predetermined polarization axis of the display panel,

incident light is not injected between the first layer and the second layer and is not injected through the plate edge, and

incident light reaching the second layer but not passing through the second major surface is returned to the first layer where a portion of the returned incident light is depolarized and diffusely backscattered in the first layer and directed toward the second layer.

2. The component of claim 1, wherein the first major surface of the plate has a texture formed thereon.

3. The component of claim 1, wherein the second layer is further configured to diffuse light.

4. The component of claim 1, wherein the second layer is further configured to reflect light.

5. The component of claim 1, wherein the second layer is further configured to backscatter light.

6. A component for use between a light source and a display panel of a liquid crystal display, the component comprising:

a plate comprising a first layer and a second layer to form a structure having a first major surface, a second major surface opposing the first major surface, and an edge joining the first and second major surfaces, the first major surface configured to allow a majority of incident light from a light source to be transmitted therethrough and defining a first side of the first layer, the second major surface configured to receive a portion of the transmitted incident light from the first layer and defining a first side of the second layer, the second major surface being adjacent to air,

wherein;

the first layer comprises a film having a microscopically varying refraction index, the first layer adapted to diffusely backscatter a portion of incident light entering the first layer and to depolarize a plane of polarization of the portion of incident light passing through the first layer,

the second layer is laminated onto to be in contact with and adjacent to the first layer and comprises a film configured to be substantially index-matched to the first layer and substantially nonabsorbent to allow passage of light through the second major surface having a plane of polarization that is substantially aligned with a predetermined polarization axis of the display panel, and to substantially prevent passage of light through the second major surface having a plane of polarization that is not substantially aligned with the predetermined polarization axis of the display panel,

incident light is not injected between the first layer and the second layer and is not injected through the plate edge, and

incident light reaching the second layer but not passing through the second major surface is returned to the first layer where a portion of the returned incident light is depolarized and diffusely backscattered in the first layer and directed toward the second layer.

7. A display device, comprising:

a light source;

a reflective surface disposed proximate the light source and configured to reflect light emitted therefrom;

a polarized display panel spaced apart from the reflective surface, the polarized display panel having a predetermined polarization axis; and

a plate disposed between the reflective surface and the polarized display panel and configured to receive the reflected light, the plate comprising a first layer and a second layer, the plate including a first major surface, a second major surface opposing the first major surface, and an edge joining the first and second major surfaces, the first major surface configured to allow a majority of the reflected light to be transmitted therethrough and defining a first side of the first layer, the second major surface configured to receive a portion of the reflected light from the first layer and defining a first side of the second layer,

wherein;

the first layer is a single, discrete structure having a microscopically varying refraction index, the first layer adapted to diffusely backscatter a portion of the reflected light entering the first layer and to depolarize a plane of polarization of the reflected light passing through the first layer,

the second layer is in contact with and adjacent to the first layer and is configured to be substantially index-matched to the first layer and substantially nonabsorbent to allow passage of light through the second major surface having a plane of polarization that is substantially aligned with a predetermined polarization axis, and to substantially prevent passage of light through the second major surface having a plane of polarization that is not substantially aligned with the predetermined polarization axis,

incident light is not injected between the first layer and the second layer and is not injected through the plate edge, and

the reflected light reaching the second layer but not passing through the second major surface is returned to the first layer where a portion of the returned reflected light is depolarized and diffusely backscattered in the first layer and directed toward the second layer.

8. A component for use between a light source and a display panel of a liquid crystal display, the light source configured to emit light having one or more planes of polarization and the display panel configured to have a predetermined polarization axis, the component comprising:

a plate including a first major surface, a second major surface opposing the first major surface, and an edge joining the first and second major surfaces, the first major surface configured to allow a majority of incident light from the light source to be transmitted therethrough toward the second major surface;

a repolarization region between the first and second major surfaces and configured to receive a majority of light transmitted through the first major surface, the repolarization region configured to diffuse and to change polarization or rotate at least one plane of polarization of the light passing therethrough;

an interface between the first and second major surfaces and having a first side and a second side, the interface first side disposed adjacent to and in contact with the repolarization region; and

a prepolarization region formed between the first and second major surfaces adjacent to and in contact with the interface, the prepolarization region configured to be substantially nonabsorbent, to allow passage of light through the second major surface having a plane of polarization that is substantially aligned with the predetermined polarization axis, and to prevent passage of light through the second major surface having a plane of polarization that is not substantially aligned with the predetermined polarization axis,

wherein the light is not injected between the repolarization region and the prepolarization region or the interface and is not injected through the plate edge.

9. The component of claim 8, wherein the repolarization region and the prepolarization region have refraction indices and the interface has a refraction index that is substantially similar to the refraction indices of the regions.

10. The component of claim 8, wherein the interface is configured to modulate at least one plane of polarization of the light from a first orientation to a second orientation.

11. The component of claim 10, wherein the interface is configured to be a quarterwave retarder.

12. A display device, comprising

a light source;

a reflective surface disposed proximate the light source and configured to reflect light emitted therefrom;

a polarized display panel spaced apart from the reflective surface, the polarized display panel having a predetermined polarization axis;

a component disposed between the reflective surface and the polarized display panel and configured to receive the reflected light, the component comprising;

a plate including a first major surface, a second major surface opposing the first major surface, and an edge joining the first and second major surfaces, the first major surface configured to allow a majority of incident light from the light source to be transmitted therethrough toward the second major surface;

a repolarization region between the first and second major surfaces and configured to receive a majority of light transmitted through the first major surface, the repolarization region configured to diffuse and to change polarization or rotate at least one plane of polarization of the light passing therethrough;

an interface between the first and second major surfaces and having a first side and a second side, the interface first side disposed adjacent to and in contact with the repolarization region; and

a prepolarization region between the first and second major surfaces adjacent to and in contact with the interface, the prepolarization region configured to be substantially nonabsorbent, to allow passage of light through the second major surface having a plane of polarization that is substantially aligned with the predetermined polarization axis, and to prevent passage of light through the second major surface having a plane of polarization that is not substantially aligned with the predetermined polarization axis,

wherein the light is not injected between the repolarization region and the prepolarization region or the interface and is not injected through the plate edge.

13. The display device of claim 12, wherein the repolarization region and the prepolarization region have refraction indices and the interface has a refraction index that is substantially similar to the refraction indices of the regions.

14. The display device of claim 12, wherein the interface is configured to modulate at least one plane of polarization of the light from a first orientation to a second orientation.

15. The display device of claim 12, wherein the repolarization region is laminated with the prepolarization region.

16. The display device of claim 12, wherein the repolarization region and prepolarization region comprise a graded structure.