Phase delay element for transmissive and reflective type liquid crystal display

• US 7,656,480 B2
• Filed: 07/19/2005
• Issued: 02/02/2010
• 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, Park, Min-Soo, Uh, Kee-Han, Yun, Jin-Hyuk
• Primary Examiner(s): Dudek; James A
• Application Number:
  US11/184,436
• Publication Number:
  US 20060012737A1
• Time in Patent Office: 1,659 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 ¼ 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 ¼ 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 transmissive and reflective type LCD comprising:

a first substrate;

a reflection layer disposed on the first substrate;

a second substrate having an inner surface that is arranged so as to face the first substrate;

a liquid crystal layer formed between the first substrate and the second substrate;

a first polarizing plate formed on an outer surface of the first substrate;

a backlight arranged at a rear side of the first polarizing plate;

a brightness enhancement layer located between the backlight and the reflection layer, and

wherein the brightness enhancement layer delays a phase of the light that has passed through the brightness enhancement layer by about λ

/4.

2. The transmissive and reflective type LCD of claim 1, further comprising an second retardation film disposed between the first substrate and the liquid crystal layer.

3. The transmissive and reflective type LCD of claim 2, wherein the LCD includes at one least of pixel portion and the pixel portion is divided into a transmissive portion and a reflective portion.

4. The transmissive and reflective type LCD of claim 3, wherein a cell-gap of the transmissive portion is different from that of the reflective portion.

5. The transmissive and reflective type LCD of claim 4, wherein at least one surface of the brightness enhancement layer is defined by concave and convex portions.

6. The transmissive and reflective type LCD of claim 3, wherein at least one surface of the brightness enhancement layer is defined by concave and convex portions.

7. The transmissive and reflective type LCD of claim 2, wherein the LCD includes at one least of pixel portion and the pixel portion is divided into a transmissive portion and a reflective portion,

wherein a cell-gap of the transmissive portion is different from that of the reflective portion.

8. The transmissive and reflective type LCD of claim 7, wherein at least one surface of the brightness enhancement layer is defined by concave and convex portions.

9. The transmissive and reflective type LCD of claim 2, wherein at least one surface of the brightness enhancement layer is defined by concave and convex portions.

10. The transmissive and reflective type LCD of claim 1, wherein the LCD includes at one least of pixel portion and the pixel portion is divided into a transmissive portion and a reflective portion.

11. The transmissive and reflective type LCD of claim 10, wherein a cell-gap of the transmissive portion is different from that of the reflective portion.

12. The transmissive and reflective type LCD of claim 11, wherein at least one surface of the brightness enhancement layer is defined by concave and convex portions.

13. The transmissive and reflective type LCD of claim 10, wherein at least one surface of the brightness enhancement layer is defined by concave and convex portions.

14. The transmissive and reflective type LCD of claim 1, wherein the LCD includes at one least of pixel portion and the pixel portion is divided into a transmissive portion and a reflective portion,

wherein a cell-gap of the transmissive portion is different from that of the reflective portion.

15. The transmissive and reflective type LCD of claim 14, wherein at least one surface of the brightness enhancement layer is defined by concave and convex portions.

16. The transmissive and reflective type LCD of claim 1, wherein at least one surface of the brightness enhancement layer is defined by concave and convex portions.

17. The transmissive and reflective type LCD of claim 2, wherein the second retardation film delays a phase of light passing through the liquid crystal layer by about λ

/4.

18. The transmissive and reflective type LCD of claim 1, wherein the brightness enhancement layer includes a cholesteric liquid crystal.

19. The transmissive and reflective type LCD of claim 15, wherein each of the concave portions of the first surface of the brightness enhancement layer is defined with a substantially flat section, and each of the convex portions of the first surface of the brightness enhancement layer is defined with a rounded section.