1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to an LCD device with reduced thickness and bezel width.
2. Discussion of the Related Art
LCD devices display an image by using thin film transistors (TFTs) as switching elements. The LCD devices are widely used as display devices for notebook computers, tablet computers, smartphones, portable display devices, and various portable information devices, in addition to televisions or monitors. Since the LCD devices cannot self-emit light, the LCD devices display an image by using light emitted from a backlight unit which is disposed under a liquid crystal display panel.
FIG. 1 is a cross-sectional view schematically illustrating a portion of a general LCD device.
Referring to FIG. 1, the general LCD device includes a liquid crystal display panel 10, a backlight unit 20, a lower case 30, a guide panel 40, and an upper case 50.
The liquid crystal display panel 10 includes a lower substrate 12 and an upper substrate 14 which are coupled to each other with a liquid crystal layer therebetween, and displays an image by using light emitted from the backlight unit 20. Polarizing films 16 and 18 are adhered to a bottom and top of the liquid crystal display panel 10, respectively.
The backlight unit 20 is disposed under the liquid crystal display panel 10, and irradiates light on the bottom of the liquid crystal display panel 10. The backlight unit 20 includes: a reflective sheet 21 that is disposed at the lower caser 30; a light source module 23 that is disposed at one side of the lower case 30, and emits light; a light guide plate 25 that is disposed on the reflective sheet 21, and guides light, which is incident from the light source module 23 onto a light input part, toward the liquid crystal display panel 10; a plurality of optical sheets 27 that are disposed on the light guide panel 25, and enhance a luminance characteristic of light traveling from the light guide plate 25 to the liquid crystal display panel 10; and a light source housing 29 that supports the light source module 23.
The light source module 23 includes a light emitting diode (LED) array board 23a and a plurality of LED packages 23b. The LED array board 23a is disposed at a side wall of the light source housing 29 to face the light input part of the light guide plate 25. A plurality of driving power lines, which respectively supply driving power to the plurality of LED packages 23b, are formed at the LED array board 23a. 
The plurality of LED packages 23b are mounted at certain intervals on the LED array board 23a, and emit light with the driving power supplied from the respective driving power lines to irradiate the light having certain luminance on the light input part of the light guide plate 25. The light emitted from the plurality of LED packages 23b is incident on the light input part of the light guide plate 25, is reflected from and refracted inside the light guide plate 25, and is irradiated on the liquid crystal display panel 10 through the plurality of optical sheets 27 along with light reflected by the reflective sheet 21.
The lower case 30 is provided to have an accommodating space. The lower case 30 accommodates the backlight unit 20, and supports the guide panel 40.
The guide panel 40 is provided in a tetragonal band shape to the support a bottom edge portion of the liquid crystal display panel 10. The guide panel 40 includes a panel supporting part, which supports the bottom edge portion of the liquid crystal display panel 10, and a guide side wall that is formed vertically to the panel supporting part and surrounds all side walls of the backlight unit 20.
The upper case 50 is provided in a tetragonal band shape in order for one side of the upper case 50 to have a ┌-shape, and surrounds a top edge portion of the liquid crystal display panel 10 and all side surfaces of the guide panel 40.
As described above, the general LCD device includes a certain gap G that is provided between the bottom of the liquid crystal display panel 10 and a top of the optical sheet 27. This, as illustrated in FIGS. 2 and 3, is for preventing mura from occurring due to interference between elements caused by a bending or twist of the liquid crystal display panel 10, the light guide plate 25, and the optical sheet 27. In particular, the mura mainly occurs due to a contact between the optical sheets 27 and the liquid crystal display panel 10 when moisture penetrates into the gap G at an environment of high temperature and humidity.
In order to prevent the mura, the optical sheet 27 and the liquid crystal display panel 10 should be separated from each other by an interval of 1.5 mm to 2 mm, in which case a thickness T of the LCD device increases due to the gap G between the optical sheet 27 and the liquid crystal display panel 10.
Moreover, in the general LCD device, the guide panel 40 maintains a constant interval between the optical sheet 27 and the liquid crystal display panel 10 and supports the liquid crystal display panel 10, and the upper case 50 covers the top edge portion of the liquid crystal display panel 10. Therefore, a bezel width W increases due to the guide panel 40 and the upper case 50.
For this reason, the general LCD device has a limitation in reducing the thickness T and bezel width W thereof.