Backlight unit and liquid crystal display including the same

Abstract

A liquid crystal display includes a liquid crystal display panel, a backlight and a cover. The backlight includes optical sheets that are configured to be mounted to the cover using a plurality of holes provided on the optical sheet that material to corresponding protrusions provided on the cover. The holes and protrusions are configured to reduce damage or misalignment to the optical sheet that may be caused by heat generated inside the liquid crystal display.

What is claimed is: 
     
       1. A display device comprising:
 a display panel having a plurality of electrodes and pixels;   a backlight provided adjacent to the display panel, the backlight unit including at least one light guide panel having at least one light incident area to receive light from a first direction and a light emitting area to emit light received through the light incident area in a second direction, the first and second directions being different directions;   at least one light source, at least one incident area of the light guide panel being adjacent to at least one light source to receive light output;   a reflector adjacent to the light guide panel to reflect light towards the second direction; and   at least one optical sheet provided between the display panel and the backlight, the at least one optical sheet including a first optical sheet; and   a cover provided adjacent to the display panel or the backlight, wherein the cover includes a first rail near a first side of the cover and a second rail near a second side of the cover, the first and second sides being opposite sides, the first optical sheet has a first slot near a first side and a second slot near a second side, the first and second sides being opposite sides of the first optical sheet, and the first slot is fitted over the first rail and the second slot is fitted over the second rail,   wherein the cover further includes a third rail near a third side, which is between the first and second sides, and the first optical sheet further includes a third slot near third side, which is between the first and second sides of the first optical sheet, the third slot being fitted over the third rail,   wherein the first side and the second side of the optical sheet are longer than the third side of the optical sheet, and   wherein the first slot is smaller than the second slot and the third slot.   
     
     
       2. The display device of  claim 1 , wherein the first and second rails have the same size. 
     
     
       3. The display device of  claim 1 , wherein when the display device is positioned to be vertical such that the second direction is perpendicular to a direction of gravity, the first slot of the first optical sheet hangs onto the first rail, and the second slot is provided loosely over the second rail. 
     
     
       4. The display device of  claim 1 , wherein the first optical sheet includes a plurality of tab portions, a first tab portion extending from the first side of the optical sheet and the first slot being provided on the first tab portion, and a second tab portion extending from the second side of the optical sheet and the second slot being provided on the second tab portion. 
     
     
       5. The display device of  claim 4 , wherein the backlight is provided within a first area of the cover, and at least a portion of the first tab portion and the second tab portion are provided outside of the first area. 
     
     
       6. The display device of  claim 4 , wherein the at least one light guide panel is provided within a first area of the cover, and the at least a portion of the first tab portion and the second tab portion are provided outside of the first area. 
     
     
       7. The display device of  claim 1 , wherein the first optical sheet includes a plurality of tab portions, a first tab portion extending from the first side of the optical sheet and the first slot being provided on the first tab portion, a second tab portion extending from the second side of the optical sheet and the second slot being provided on the second tab portion, and a third tab portion extending from the third side of the optical sheet and the third slot being provided on the third tab portion. 
     
     
       8. The display device of  claim 1 , wherein the third rail has a first width and a first length and the third slot has a first width and a first length, the first width of the third slot being larger than the first width of the third rail by 2 mm to 10 mm, and the first length of the third slot being larger than the first length of the third rail by 0.15 mm to 1.3 mm. 
     
     
       9. The display device of  claim 1 , wherein the first rail has a first width and a first length and the first slot has a first width and a first length, the first width of the first slot being larger than the first width of the first rail by 0.2 mm to 2 mm, and the first length of the first slot being larger than the first length of the first rail by 0.15 mm to 1.3 mm. 
     
     
       10. The display device of  claim 1 , wherein the second rail has a first width and a first length and the second slot has a first width and a first length, the first width of the second slot being larger than the first width of the second rail by 2 mm to 10 mm, and the first length of the second slot being larger than the first length of the second rail by 0.2 mm to 2 mm. 
     
     
       11. A display device comprising:
 a display panel having a plurality of electrodes and pixels;   a backlight provided adjacent to the display panel;   at least one optical sheet provided between the display panel and the backlight, the at least one optical sheet including a first optical sheet; and   a cover provided adjacent to the display panel or the backlight, wherein   the cover includes a first rail near a first side of the cover and a second rail near a second side of the cover, the first and second sides being opposite sides,   the first optical sheet has a first slot near a first side and a second slot near a second side,   the first and second sides being opposite sides of the first optical sheet, and   the first slot is fitted over the first rail and the second slot is fitted over the second rail,   wherein the cover further includes a third rail near a third side, which is between the first and second sides, and the first optical sheet further includes a third slot near third side, which is between the first and second sides of the first optical sheet, the third slot being fitted over the third rail, and   wherein a length of the first slot in a direction parallel to the first side is less than a length of the second slot in a direction parallel to the second side and a length of the third slot in a direction parallel to the third side.   
     
     
       12. The display device of  claim 11 , wherein the first and second rails have the same size. 
     
     
       13. The display device of  claim 11 , wherein the first optical sheet includes a plurality of tab portions, a first tab portion extending from the first side of the optical sheet and the first slot being provided on the first tab portion, and a second tab portion extending from the second side of the optical sheet and the second slot being provided on the second tab portion. 
     
     
       14. The display device of  claim 13 , wherein the backlight is provided within a first area of the cover, and at least a portion of the first tab portion and the second tab portion are provided outside of the first area. 
     
     
       15. The display device of  claim 13 , wherein the at least one light guide panel is provided within a first area of the cover, and the at least a portion of the first tab portion and the second tab portion are provided outside of the first area. 
     
     
       16. The display device of  claim 11 , wherein the first rail has a first width and a first length and the first slot has a first width and a first length, the first width of the first slot being larger than the first width of the first rail by 0.2 mm to 2 mm, and the first length of the first slot being larger than the first length of the first rail by 0.15 mm to 1.3 mm. 
     
     
       17. The display device of  claim 11 , wherein the second rail has a first width and a first length and the second slot has a first width and a first length, the first width of the second slot being larger than the first width of the second rail by 2 mm to 10 mm, and the first length of the second slot being larger than the first length of the second rail by 0.2 mm to 2 mm. 
     
     
       18. The display device of  claim 11 , wherein the first side and the second side of the optical sheet is longer than the third side of the optical sheet. 
     
     
       19. A backlight unit comprising:
 a housing including a first plurality of fixing parts and a second plurality of fixing parts protruding from the housing;   a plurality of light sources; and   at least one optical sheet disposed at a first side of the plurality of light sources, the at least one optical sheet including:   a first plurality of holes at a first edge of the optical sheet and configured to be coupled to the first plurality of fixing parts and comprising at least a first upper hole, second upper hole, and third upper hole,   wherein the third upper hole is located between the first upper hole and the second upper hole along the first edge, and   wherein the third upper hole has a smallest size among all of the first plurality of holes; and   a second plurality of holes at a second edge of the optical sheet opposite the first edge and configured to be coupled to the second plurality of fixing parts,   wherein the second plurality of holes comprises a first lower hole and a second lower hole being two holes that are positioned closest among the second plurality of holes to a vertical axis perpendicular to the second edge and aligned with a center of the third upper hole at the first edge;   wherein a distance from a first side edge of the optical sheet to the third upper hole is different than a distance from the first side edge to both of the first lower hole and the second lower hole.   
     
     
       20. The backlight unit of claim 19, wherein a position of the third upper hole along the first edge is not symmetrical with a position of any of the second plurality of holes along the second edge with respect to a transverse axis of the optical sheet. 
     
     
       21. The backlight unit of claim 19, wherein each of the second plurality of holes are positioned along the second edge such that a respective center of each hole of the second plurality of holes is not coincident with the vertical axis. 
     
     
       22. The backlight unit of claim 19, wherein a distance between the first upper hole and the second upper hole along the first edge is greater than a distance between the first lower hole and the second lower hole along the second edge. 
     
     
       23. The backlight unit of claim 19, wherein the distance from the first side edge to the third upper hole is less than the distance from the first side edge to the second lower hole. 
     
     
       24. The backlight unit of claim 19, wherein the first plurality of holes further comprises a fourth upper hole between the third upper hole and the second upper hole,
 the second upper hole is adjacent to a second side edge opposite the first side edge; and   wherein the second plurality of holes further comprises a third lower hole between the second lower hole and the second side edge.   
     
     
       25. The backlight unit of claim 24, wherein the distance from the second upper hole to the fourth upper hole is different than a distance from the third lower hole to the second lower hole along the second edge. 
     
     
       26. The backlight unit of claim 25, wherein the distance from the second upper hole to the fourth upper hole is greater than the distance between the third lower hole to the second lower hole. 
     
     
       27. The backlight unit of claim 25, wherein a distance from the second side edge to the second upper hole is less than a distance from the second side edge to the third lower hole. 
     
     
       28. The backlight unit of claim 27, wherein a distance from the third upper hole to the fourth upper hole is less than a distance from the first lower hole to the second lower hole. 
     
     
       29. The backlight unit of claim 19, wherein at least one of the first plurality of holes or the second plurality of holes is positioned between a plurality of data driving circuits. 
     
     
       30. The backlight unit of claim 19, wherein the plurality of first holes and the plurality of second holes are positioned at corresponding protruding portions respectively protruding from the first edge and the second edge of the optical sheet. 
     
     
       31. The backlight unit of claim 19, wherein respective positions of the first plurality of holes and the second plurality of holes are asymmetrical with respect to a transverse axis of the optical sheet. 
     
     
       32. The backlight unit of claim 19, wherein a number of the first plurality of holes is different than a number of the second plurality of holes. 
     
     
       33. The backlight unit of claim 32, wherein the number of the first plurality of holes is greater than a number of the second plurality of holes. 
     
     
       34. The backlight unit of claim 19, wherein the plurality of first holes are positioned toward an inner side of the first edge of the optical sheet and the plurality of second holes are positioned toward an inner side of the second edge of the optical sheet. 
     
     
       35. The backlight unit of claim 19, wherein a first opening distance of each of the first plurality of holes is greater than a second opening distance of the first plurality of holes, wherein the first opening distance is a distance of each hole in a direction parallel to the first edge and the second opening distance is a distance of each hole in a direction perpendicular to the first opening distance. 
     
     
       36. The backlight unit of claim 35, wherein a corresponding first opening distance of at least one of the first plurality of holes is different from a corresponding first opening distance of at least another one of the first plurality of holes. 
     
     
       37. The backlight unit of claim 35, wherein a corresponding first opening distance of the third upper hole is less than corresponding first opening distances of the first upper hole or the second upper hole. 
     
     
       38. The backlight unit of claim 35, wherein a corresponding second opening distance of the third upper hole is substantially equal to corresponding second opening distances of the first upper hole or the second upper hole. 
     
     
       39. A backlight unit comprising:
 a housing including a first plurality of fixing parts and a second plurality of fixing parts protruding from the housing;   a plurality of light sources; and   at least one optical sheet disposed at a first side of the plurality of light sources, the at least one optical sheet including:   a first plurality of holes at a first edge of the optical sheet and configured to be coupled to the first plurality of fixing parts and comprising at least a first upper hole, second upper hole, and third upper hole,   wherein the third upper hole is located between the first upper hole and the second upper hole along the first edge, and   wherein the third upper hole has a smallest size among all of the first plurality of holes; and   a second plurality of holes at a second edge of the optical sheet opposite the first edge and configured to be coupled to the second plurality of fixing parts,   wherein the second plurality of holes comprises a first lower hole and a second lower hole being two holes that are positioned closest among the second plurality of holes to a first vertical axis perpendicular to the second edge and aligned with a center of the third upper hole at the first edge,   wherein the first vertical axis is offset from a center of the first edge,   wherein a distance from the first upper hole to the third upper hole is different from a distance from the third upper hole to the second upper hole, and   wherein a distance along the second edge from the first lower hole to the first vertical axis is different than a distance along the second edge from the second lower hole to the first vertical axis.   
     
     
       40. The backlight unit of claim 39, wherein a number of the first plurality of holes is greater than a number of the second plurality of holes. 
     
     
       41. The backlight unit of claim 40, wherein none of the positions of the first plurality of holes along the first edge are symmetrical with any of the positions of the second plurality of holes along the second edge with respect to a transverse axis of the optical sheet. 
     
     
       42. The backlight unit of claim 39, wherein a distance from the first side edge to the first upper hole along the first edge is the same as a distance from a second side edge opposite the first side edge to the second upper hole along the first edge. 
     
     
       43. The backlight unit of claim 39, wherein a distance from the first side edge to the first lower hole along the second edge is the same as a distance from a second side edge opposite the first side edge to the second lower hole along the second edge. 
     
     
       44. A backlight unit comprising:
 a housing including a first plurality of fixing parts and a second plurality of fixing parts protruding from the housing;   a plurality of light sources; and   at least one optical sheet disposed at a first side of the plurality of light sources, the at least one optical sheet including:   a first plurality of holes at a first edge of the optical sheet and configured to be coupled to the first plurality of fixing parts and comprising at least a first upper hole, second upper hole, and third upper hole,   wherein the third upper hole is located between the first upper hole and the second upper hole along the first edge, and   wherein the third upper hole has a smallest size among all of the first plurality of holes; and   a second plurality of holes at a second edge of the optical sheet opposite the first edge and configured to be coupled to the second plurality of fixing parts,   wherein the second plurality of holes comprises a first lower hole and a second lower hole being two holes that are positioned closest among the second plurality of holes to a first vertical axis perpendicular to the second edge and aligned with a center of the third upper hole at the first edge,   wherein the first vertical axis is offset from a center of the first edge,   wherein a distance from the first upper hole to the third upper hole is different from a distance from the third upper hole to the second upper hole,   wherein the first lower hole is positioned closest to the first side edge along the second edge among the second plurality of holes and the second lower hole is positioned closest to a second side edge opposite the first side edge along the second edge among the second plurality of holes, and   wherein a distance along the second edge from the first lower hole to the first vertical axis is different than a distance along the second edge from the second lower hole to the first vertical axis.   
     
     
       45. The backlight unit of claim 44, wherein a number of the first plurality of holes is greater than a number of the second plurality of holes. 
     
     
       46. The backlight unit of claim 45, wherein none of the positions of the first plurality of holes along the first edge are symmetrical with any of the positions of the second plurality of holes along the second edge with respect to a transverse axis of the optical sheet. 
     
     
       47. The backlight unit of claim 44, wherein a distance from the first side edge to the first upper hole along the first edge is the same as a distance from the second side edge to the second upper hole along the first edge. 
     
     
       48. The backlight unit of claim 44, wherein a distance from the first side edge to the first lower hole along the second edge is the same as a distance from the second side edge to the second lower hole along the second edge.