Backlight assembly and display device having the same

• US 20060262569A1
• Filed: 12/30/2005
• Published: 11/23/2006
• Est. Priority Date: 05/19/2005
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Joong-Hyun, Choi, Seong-Sik, Hwang, In-Sun
• Application Number:
  US11/323,124
• Publication Number:
  US 20060262569A1
• Time in Patent Office: Days
• US Class Current: 362/626
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A light guide apparatus includes a reflecting polarizing surface and a light reflecting surface having at least one prism pattern thereon. The light guide apparatus may improve image display quality and manufacturing cost. For example, a backlight assembly includes a lamp, a light guiding plate and a reflecting sheet. The light guiding plate includes a light incident surface, a light reflecting surface and a light exiting surface. The light generated from the lamp is incident into the light incident surface. The light reflecting surface is extended from a side of the light incident surface. A plurality of first prism patterns is formed on the light reflecting surface. The light exiting surface is extended from another side of the light incident surface to correspond to the light reflecting surface. A reflective polarizing layer is formed on the light exiting surface. The reflecting sheet is on the light reflecting surface.

Claims

1. A backlight assembly comprising:

a lamp configured to generate a light;

a light guiding plate including;

a light incident surface positioned to receive the light generated by the lamp;

a light reflecting surface extending from a side of the light incident surface, the light reflecting surface including a plurality of first prism patterns having a dot shaped interface with the light reflecting surface and positioned thereon; and

a light exiting surface extending from another side of the light incident surface positioned to correspond to the light reflecting surface, the light exiting surface including a reflective polarizing layer formed thereon; and

a reflecting sheet on the light reflecting surface.

2. The backlight assembly of claim 1, wherein the reflective polarizing layer comprises a dual brightness enhancement film (DBEF) that configured to transmit a P-wave portion of the light and to reflect an S-wave portion of the light.

3. The backlight assembly of claim 1, wherein the reflective polarizing layer comprises a cholesteric liquid crystal (CLC) film configured to transmit a portion of the light having a wavelength included in a predetermined wavelength range, and further configured to reflect a remaining portion of the light.

4. The backlight assembly of claim 1, wherein each of the first prism patterns comprises a plurality of first prisms having a substantially triangular cross-section.

5. The backlight assembly of claim 4, wherein the lamp extends in a longitudinal direction, and wherein each of the first prisms extends substantially in the longitudinal direction of the lamp.

6. The backlight assembly of claim 1, wherein each of the first prism patterns protrudes from the light reflecting surface to form a convex shape.

7. The backlight assembly of claim 1, wherein each of the first prism patterns is recessed from the light reflecting surface to form a concave shape.

8. The backlight assembly of claim 7, wherein the reflecting sheet is attached to the light reflecting surface.

9. The backlight assembly of claim 1, wherein the light guiding plate further comprises a second prism pattern on the reflective polarizing layer.

10. The backlight assembly of claim 9, wherein the second prism pattern comprises a plurality of second prisms that have a substantially triangular cross-section.

11. The backlight assembly of claim 10, wherein the lamp extends in a longitudinal direction, and wherein each of the second prisms is substantially perpendicular to the longitudinal direction of the lamp.

12. A liquid crystal display device comprising:

a backlight assembly including;

a lamp configured to generate a light;

a light guiding plate including;

a light incident surface positioned to receive the light generated by the lamp;

a light reflecting surface extending from a side of the light incident surface, the light reflecting surface including a plurality of first prism patterns having a dot shape interface with the light reflecting surface and positioned thereon; and

a light exiting surface extending from another side of the light incident surface positioned to correspond to the light reflecting surface, the light exiting surface including a reflective polarizing layer formed thereon; and

a reflecting sheet on the light reflecting surface; and

a display unit including;

a liquid crystal display panel configured to display an image using the light generated from the backlight assembly; and

a driving circuit part configured to generate a control signal to drive the liquid crystal display panel.

13. The liquid crystal display device of claim 12, wherein the liquid crystal display panel comprises:

a first substrate positioned corresponding to the backlight assembly to receive light from the backlight;

a second substrate positioned corresponding to the first substrate;

a liquid crystal layer interposed between the first and second substrates;

a first polarizer on the first substrate; and

a second polarizer on the second substrate.

14. The liquid crystal display device of claim 13, wherein a polarizing axis of the reflective polarizing layer is substantially parallel to a polarizing axis of the first polarizer.

15. The liquid crystal display device of claim 14, wherein the reflective polarizing layer comprises a dual brightness enhancement film (DBEF) configured to transmit a P-wave portion of the light and to reflect an S-wave portion of the light.

16. The liquid crystal display device of claim 14, wherein the reflective polarizing layer comprises a cholesteric liquid crystal (CLC) film configured to transmit a portion of the light having a predetermined wavelength range, and further configured to reflect a remaining portion of the light.

17. The liquid crystal display device of claim 12, wherein the lamp extends in a longitudinal direction, wherein each of the first prism patterns comprises a plurality of first prisms having a substantially triangular shape, and wherein the first prisms extends substantially in the longitudinal direction of the lamp.

18. The liquid crystal display device of claim 12, wherein each of the first prism patterns is recessed from the light reflecting surface to form a concave shape, and wherein the reflecting sheet is attached to the light reflecting surface.

19. The liquid crystal display device of claim 12, wherein the light guiding plate further comprises a second prism pattern on the reflective polarizing layer.

20. The liquid crystal display device of claim 19, wherein the lamp extends in a longitudinal direction, wherein the second prism pattern comprises a plurality of second prisms having a substantially triangular cross section, and wherein the second prisms are extended substantially perpendicular to the longitudinal direction of the lamp.

21. A light guide apparatus comprising:

a light reflecting surface positioned to receive light, the light reflecting surface including a first prism pattern comprising a plurality of prism features extending in a first direction;

a light transmission surface positioned opposite the light reflecting surface, the light transmission surface configured to substantially transmit light having a first polarization state and configured to substantially reflect light having a second different polarization state.

22. The apparatus of claim 21, wherein the prism features further extend in a convex configuration from the light reflecting surface.

23. The apparatus of claim 21, wherein the prism features are in an at least partially recessed configuration with respect to the light reflecting surface.

24. The apparatus of claim 21, wherein the prism features include a portion having a substantially triangular cross section.

25. The apparatus of claim 21, wherein the prism features include a portion having a curved cross section.

26. The apparatus of claim 21, wherein the light guiding apparatus is included in a backlight assembly including a light assembly.

27. The apparatus of claim 26, wherein the light assembly includes a lamp positioned proximate to a light receiving surface of the light guiding apparatus, wherein the lamp extends in a longitudinal direction, and wherein the longitudinal direction is substantially parallel to the first direction.

28. The apparatus of claim 21, wherein the first prism pattern adjacent a region of the light receiving surface having a first shape.

29. The apparatus of claim 28, wherein the first shape including at least one curve portion.

30. The apparatus of claim 29, wherein the first shape is a dot shape.

31. The apparatus of claim 28, wherein the first shape includes at least one straight region.