1. Field of the Invention
Embodiments relate to a backlight unit and a display apparatus using the same.
2. Discussion of the Related Art
Generally, representative large-scale display apparatuses include Liquid Crystal Displays (LCDs), Plasma display Panels (PDPs), etc.
Unlike self-emission type PDPs, LCDs essentially need a separate backlight unit due to absence of self light emitting devices.
Backlight units for use in LCDs are classified into edge type backlight units and vertical type backlight units according to positions of light sources. In an edge type backlight unit, light sources are disposed at left and right edges or upper and lower edges of an LCD panel and a light guide plate is provided to uniformly distribute light throughout a surface of the LCD panel, which ensures uniform luminance and enables production of an extremely thin display panel.
A vertical type backlight unit is generally applied to displays of 20 inches or more. The vertical type backlight unit advantageously has greater light efficiency than the edge type backlight unit owing to a plurality of light sources being disposed below a panel and thus, is mainly used in a large-scale display requiring high luminance.
Conventional edge type or vertical type backlight units adopt Cold Cathode Fluorescent Lamps (CCFL) as a light source.
The backlight units using CCFLs, however, have several disadvantages, such as consumption of a great quantity of power because power should always be applied to a CCFL, low color reproduction efficiency of about 70% that of a Cathode Ray Tube (CRT), and environmental pollution due to use of mercury.
Currently, backlight units using Light Emitting Diodes (LEDs) are being studied as a solution to the above described problems.
In the case of backlight units using LEDs, turning on or off a part of an LED array is possible, which can achieve remarkable reduction in power consumption. In particular, RGB LEDs exhibit color reproduction beyond 100% of a color reproduction range proposed by the National Television System Committee (NTSC) and can provide more vivid images to consumers.
Further, LEDs fabricated through semiconductor processes are environmentally friendly.
Although LCD products using LEDs having the above described advantages have been introduced, these LCD products need expensive drivers, PCBs, etc. because LEDs have a driving mechanism different from conventional CCFLs.
For this reason, LED backlight units are applied only to high-price LCD products at present.