Phase delay element for transmissive and reflective type liquid crystal display

• US 8,314,906 B2
• Filed: 12/01/2009
• Issued: 11/20/2012
• Est. Priority Date: 07/19/2004
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Hirai, Akira, Yun, Jin-Hyuk, Uh, Kee-Han, Park, Min-Soo
• Primary Examiner(s): DUDEK, JAMES A
• Application Number:
  US12/628,482
• Publication Number:
  US 20100091216A1
• Time in Patent Office: 1,085 Days
• Field of Search: 349/114
• US Class Current: 349/114
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• 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 2413/02 Number of plates being 2

Abstract

A phase delay element includes a brightness enhancement layer intermediate a reflection layer and an artificial light. The brightness enhancement layer is defined by a first surface and an opposite second surface. The first surface faces the reflection layer. A first light from the artificial light is incident on the second surface. A phase of the first light is delayed by about 1/4 phase (λ/4) so that a second light is emitted from the first surface toward the reflection layer. The second light is reflected from the reflection layer so that a third light is emitted from the reflection layer toward the first surface. A phase of the third light is delayed by about 1/4 phase (λ/4) so that a fourth light is emitted from the second surface. Therefore, a portion of the artificial light, which is reflected from the reflection layer, is recycled to improve a luminance of an LCD apparatus.

Claims

1. A substrate comprising:

an insulating plate having a pixel area, the pixel area defined by a reflection region and a transmission window;

a switching element formed in the pixel area;

a pixel electrode electrically connected to the switching element;

a reflection layer disposed in alignment with the reflection region, the reflection layer being receptive to a front light emitted from a viewer'"'"'s side outside of the substrate being reflected from the reflection layer toward the viewer'"'"'s side, the reflection layer being receptive to a backside light emitted from a backside of the substrate opposite the viewer'"'"'s side being reflected from the reflection layer toward the backside; and

a brightness enhancement layer formed intermediate the reflection layer and the backside light, wherein the backside light being emitted from the backside toward the reflection layer through the brightness enhancement layer becomes a reflection light being emitted from the reflection layer toward the backside through the brightness enhancement layer,

wherein the brightness enhancement layer delays a phase of the backside light by about 1/4 phase providing a phase-delayed backside light to the reflection layer, and the brightness enhancement layer delays a phase of the reflection light by about 1/4 phase providing a phase-delayed reflection light to the backside.

2. The substrate of claim 1, wherein the brightness enhancement layer delays a phase of the backside light providing a phase-delayed backside light to the reflection layer, and the brightness enhancement layer delays a phase of the reflection light to providing a phase-delayed reflection light to the backside.

3. The substrate of claim 1, wherein the brightness enhancement layer is defined having a substantially identical thickness.

4. The substrate of claim 1, wherein the brightness enhancement layer is defined by a first surface and an opposite second surface integrally formed with the first surface, the first surface being disposed facing a reflection layer, the first and second surfaces each being substantially non-planar.

5. The substrate of claim 1, wherein the brightness enhancement layer is disposed between the insulating plate and the switching element.

6. The substrate of claim 1 wherein the brightness enhancement layer is disposed between the switching element and the pixel electrode.

7. The substrate of claim 1, further including:

an organic insulating layer disposed over the switching element of which a drain electrode is exposed in the reflection region, the substrate being exposed in the transmission window; and

a passivation layer disposed over the organic insulating layer, the passivation layer being formed on the pixel electrode connected with the reflection layer,

wherein the reflection layer is formed in an upper area defining the passivation layer corresponding to the reflection region.

8. The substrate of claim 7, wherein the brightness enhancement layer is formed on a surface of the organic insulating layer.

9. The substrate of claim 1, further comprising:

a color filter formed in the pixel area; and

a common electrode layer formed on the insulating plate having the color filter in the pixel area.

10. The substrate of claim 1, wherein the brightness enhancement layer is disposed under the transmission window and delays a phase of the backside light by about 1/4 phase providing a phase-delayed backside light to the transmission window.

11. A phase delay element for a LCD apparatus comprising:

a brightness enhancement layer disposed between a backlight and a reflection layer, the brightness enhancement layer defined by a bottom member and a counter member, the counter member being integrally formed with the bottom member, the counter member being disposed facing the reflection layer,

wherein a first light having a wavelength phase (λ

) incident on the bottom member is delayed by about 1/4 phase (λ

/4) emitting a second light that from the counter member toward the reflection layer, the second light being reflected from the reflection layer to become a third light that is emitted from the reflection layer toward the counter member, a phase of the third light is delayed by about 1/4 phase (λ

/4) passing through the brightness enhancement layer emitting a fourth light from the bottom member.

12. The phase delay element of claim 11, wherein the first light is circularly polarized, the second light and the third light are vertically polarized, and the fourth light is circularly polarized in a same direction as a direction of the first light.

13. The phase delay element of claim 11, wherein the counter member is defined with a substantially non-planar surface.

14. The phase delay element of claim 11, wherein the bottom member is defined with a substantially non-planar surface.

15. The phase delay element of claim 11, wherein the bottom member and the counter member are solidified cholesteric liquid crystal.

16. The phase delay element of claim 11, wherein the counter member is defined with concave and convex portions.

17. The phase delay element of claim 16, wherein the concave and convex portions of the counter member are rounded.

18. The phase delay element of claim 16, wherein the concave portions of the counter member are defined with flat sections, and the convex portions of the counter member are defined by rounded sections.