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 plurality of first fixing parts protruding from the housing and a plurality of second fixing parts protruding from the housing;   a plurality of light source devices; and   at least one optical sheet disposed on the plurality of light source devices, the at least one optical sheet including:   a plurality of upper holes at an upper side of the at least one optical sheet and coupled to the plurality of first fixing parts and a plurality of lower holes at a lower side of the at least one optical sheet and coupled to the plurality of second fixing parts,   wherein a location of the plurality of upper holes and a location of the plurality of lower holes are asymmetrical with respect to a center line between the upper side and the lower side,   wherein the plurality of upper holes includes a first hole adjacent to an edge of the upper side, a second hole adjacent to the other edge of the upper side and a third hole between the first hole and the second hole, and   a size of the third hole is smaller than a size of the first or the second hole.   
     
     
       20. The backlight unit of claim 19, wherein a number of the plurality of upper holes is different from a number of the plurality of lower holes. 
     
     
       21. The backlight unit of claim 20, wherein the number of the plurality of upper holes is greater than the number of the plurality of lower holes. 
     
     
       22. The backlight unit of claim 20, wherein the number of the plurality of upper holes is smaller than the number of the plurality of second holes. 
     
     
       23. The backlight unit of claim 19, wherein the plurality of upper and second holes are formed at a plurality of protrusions of the at least one optical sheet. 
     
     
       24. The backlight unit of claim 23, wherein each of the upper hole is formed at each of the protrusions of the at least one optical sheet. 
     
     
       25. The backlight unit of claim 24, wherein a size of each of the upper holes is different from each other. 
     
     
       26. The backlight unit of claim 19, wherein the location of the plurality of upper holes is mis-aligned with the location of the plurality of lower holes. 
     
     
       27. The backlight unit of claim 19, wherein the at least one upper or lower holes is formed at an inner side of the at least one optical sheet, the inner side being at a periphery of the at least one optical sheet. 
     
     
       28. The backlight unit of claim 19, wherein a length of a short axis of the third hole is substantially equal to a length of a short axis of the first or the second hole. 
     
     
       29. The backlight unit of claim 19, wherein a first distance of the plurality of upper holes is longer than a second distance of the plurality of upper holes, the first distance is a distance of the upper hole in a direction along the upper side, the second distance is a distance of the upper hole in a direction perpendicular to the first distance. 
     
     
       30. The backlight unit of claim 29, wherein at least one of the first distance of the plurality of upper holes is different from at least one other of the first distance of the plurality of upper holes. 
     
     
       31. The backlight unit of claim 19, wherein a length of a long axis of the third hole is shorter than a length of a long axis of the lower hole. 
     
     
       32. A backlight unit comprising:
 a housing including a plurality of first fixing parts protruding from the housing and a plurality of second fixing parts protruding from the housing;   a plurality of light source devices; and   at least one optical sheet disposed above the plurality of light source devices, the at least one optical sheet including:   a plurality of upper holes at an upper side of the at least one optical sheet and coupled to the plurality of first fixing parts and a plurality of lower holes at a lower side of the at least one optical sheet and coupled to the plurality of second fixing parts,   wherein a location of the plurality of upper holes and a location of the plurality of lower holes are asymmetrical with respect to a center line between the upper side and the lower side,   wherein the plurality of upper holes includes a first hole adjacent to an edge of the upper side, a second hole adjacent to the other edge of the upper side and a third hole between the first hole and the second hole,   wherein a length of a long axis of the third hole is shorter than a length of a long axis of the first or the second hole, and   wherein a length of a short axis of the third hole is shorter than a length of a short axis of at least one of the plurality of lower holes.   
     
     
       33. The backlight unit of claim 32, wherein a size of the plurality of upper holes is smaller than a size of the plurality of lower holes. 
     
     
       34. The backlight unit of claim 32, wherein the plurality of upper and lower holes are formed at protrusions of the at least one optical sheet. 
     
     
       35. The back light unit of claim 34, wherein each of the upper holes is formed at each of the protrusions of the at least one optical sheet. 
     
     
       36. The backlight unit of claim 35, wherein a size of each of the upper holes is different from each other. 
     
     
       37. The backlight unit of claim 32, wherein a size of the plurality of upper holes is greater than a size of the plurality of lower holes. 
     
     
       38. The backlight unit of claim 31, wherein a first distance of the plurality of upper holes is longer than a second distance of the plurality of upper holes, the first distance is a distance of the upper hole in a direction along the upper side, and the second distance is a distance of the upper hole in a direction perpendicular to the first distance. 
     
     
       39. The backlight unit of claim 32, wherein the location of the plurality of upper holes is mis-aligned with the location of the plurality of lower holes.