Light guide plate and backlight unit having same

• US 8,845,170 B2
• Filed: 06/29/2009
• Issued: 09/30/2014
• Est. Priority Date: 07/03/2008
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Kim, Sang-Soo, Choi, Jin-Sung, Jang, Tae-Seok, Lee, Sang-Hoon
• Primary Examiner(s): HAN, JASON
• Application Number:
  US12/493,762
• Publication Number:
  US 20100002466A1
• Time in Patent Office: 1,919 Days
• Field of Search: 362/97.3, 362/608, 362/610, 362/612, 362621-622, 349/65, 349/69
• US Class Current: 362/608
• CPC Class Codes: G02B 6/003 Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

In a light guide plate and a backlight unit, a light guide plate includes a light incident surface, an opposite surface, a top surface, a bottom surface, and a plurality of optical path changing units. The optical path changing units are aligned on at least the bottom surface of the top surface and the bottom surface at a predetermined interval while protruding in parallel to a reference line perpendicular to the light incident surface. Accordingly, power consumption used to generate the light may be reduced.

Claims

1. A backlight unit comprising:

a plurality of light sources, the light sources being individually dimmable and including a first light source;

a light guide plate that comprises a light incident surface to receive light directly or indirectly from the plurality of light sources; and

a first plurality of optical path changing units integrated with or disposed adjacent to the light guide plate and including a first optical path changing unit, the first optical path changing unit including a curved surface that is convex toward the first light source and no surface that is concave relative to the first light source, the first optical path changing unit being structured to substantially refract light output from the first light source for providing refracted light,

wherein each light source among the light sources is placed at a focal length point at a distance relative to a corresponding optical path changing unit among the optical path changing units for the corresponding optical path changing unit to refract light incident onto the corresponding optical path changing unit into parallel light rays.

2. The backlight unit of claim 1, wherein the first optical path changing unit is integrally formed with the light guide plate and comprises a lens protruding outward from the light incident surface toward the first light source.

3. The backlight unit of claim 2, wherein the lens has a semi-circular surface.

4. The backlight unit of claim 1, wherein the optical path changing units are placed between the light sources and the light guide plate.

5. The backlight unit of claim 4, wherein the first optical path changing unit comprises a lens corresponding to the first light source.

6. The backlight unit of claim 1, wherein the first optical path changing unit includes a partial-cylindrical structure, the partial-cylindrical structure including a flat side connected to the light incident surface and a curved side facing the first light source.

7. The backlight unit of claim 1, wherein the first optical path changing unit includes a partial-circular top surface and a partial-circular bottom surface, the partial-circular bottom surface being connected to the partial-circular top surface through the curved surface.

8. The backlight unit of claim 1, wherein the first optical path changing unit includes a convex lens for refracting light rays emitted by the first light source into parallel light rays.

9. The backlight unit of claim 1, wherein the optical path changing units and the light guide plate include a same material.

10. The backlight unit of claim 1, wherein the first optical path changing unit has a refractive index in a range of about 1.5 to about 1.6.

11. The backlight unit of claim 1, wherein the first light source is spaced apart from the optical path changing units.

12. The backlight unit of claim 1, wherein the first light source is disposed outside the optical path changing units.

13. The backlight unit of claim 1, further comprising:

a second plurality of light sources corresponding to a second light incident surface of the light guide plate, the second plurality of light sources including a second light source; and

a second plurality of optical path changing units disposed between the second light source and the second light incident surface of the light guide plate,

wherein the light guide plate is disposed between the first plurality of optical path changing units and the second plurality of optical path changing units.

14. The backlight unit of claim 13, wherein the second plurality of optical path changing units refract light emitted by the second light source to provide refracted light that is parallel to the refracted light provided by the first optical path changing unit.

15. The backlight unit of claim 13 further comprising:

a third plurality of light sources corresponding to a third light incident surface of the light guide plate, the third plurality of light sources including a third light source; and

a third plurality of optical path changing units disposed between the third light source and the third light incident surface of the light guide plate.

16. The backlight unit of claim 15 further comprising:

a fourth plurality of light sources corresponding to a fourth light incident surface of the light guide plate, the fourth plurality of light sources including a fourth light source; and

a fourth plurality of optical path changing units disposed between the fourth light source and the fourth light incident surface of the light guide plate.

17. The backlight unit of claim 1, wherein the refracted light includes a light ray that is perpendicular to the light incident surface.