TECHNICAL FIELD

The disclosure relates to a liquid crystal display device, and more particularly, to a liquid crystal display device including a reflective sheet.

BACKGROUND ART

Recently, a liquid crystal display device using light emitting diodes as a light source is gradually increasing in size.

A liquid crystal panel used in the liquid crystal display device cannot emit light by itself, and therefore, requires a separate light source.

Accordingly, the liquid crystal display device is provided with a backlight device including a light source on the rear of the liquid crystal panel. When the backlight device irradiates light toward the liquid crystal panel, the liquid crystal panel may display an image.

In general, the backlight device may be classified into an edge type backlight device and a direct type backlight device according to an arrangement structure of the light source.

The edge type backlight device has a structure in which a light source is disposed on one side of a light guide plate, or a pair of light sources are disposed on both sides of the light guide plate. A reflective sheet is provided under the light guide plate to reflect the light exiting the rear surface of the light guide plate toward the liquid crystal panel.

On the other hand, the direct type backlight device has a structure in which a plurality of light sources are disposed under the light guide plate. A reflective sheet is provided under the light guide plate, and reflects the light reflected and returned by an optical sheet such as a diffusion plate provided on the upper surface of the light guide plate back toward the liquid crystal panel.

However, because the reflective sheet is disposed adjacent to the light source that generates heat, there is a problem that the reflective sheet may shrink and expand due to heat. When the reflective sheet has a large shrinkage and expansion, a wrinkle phenomenon in which the reflective sheet is wrinkled may occur.

When the wrinkle phenomenon of the reflective sheet occurs, a luminance difference may occur between the region of the liquid crystal panel corresponding to the region of the reflective sheet where the wrinkle phenomenon has occurred and the region of the liquid crystal panel corresponding to the region of the reflective sheet where the wrinkle phenomenon does not occur. Due to this difference in luminance, a spot phenomenon may appear in an image displayed on the liquid crystal panel.

In addition, as liquid crystal display devices become larger and larger, beadings are formed in the lower chassis supporting the reflective sheet to increase the strength of the lower chassis. However, in this case, there may be a problem that a portion of the reflective sheet corresponding to the beading sags. When the portion of the reflective sheet sags into the beading, a spot phenomenon may appear in an image displayed on the liquid crystal panel similar to the wrinkle phenomenon of the reflective sheet.

In addition, as the liquid crystal display devices become larger and larger, the flatness of the lower chassis supporting the reflective sheet may not be uniform. When the flatness of the lower chassis is not good, a spot phenomenon may appear in an image displayed on the liquid crystal panel similar to the wrinkle phenomenon of the reflective sheet.

In order to solve such a phenomenon, increasing the thickness of the reflective sheet may be considered. However, this increases the overall thickness of the liquid crystal display device, so there is a problem in that the trend of slimming is reversed. Therefore, a reflective sheet having a thin thickness and high stiffness is required.

DISCLOSURE OF INVENTION

Technical Problem

The disclosure has been developed in order to overcome the above drawbacks and other problems associated with the conventional arrangement. An aspect of the disclosure relates a liquid crystal display device including a reflective sheet capable of improving stiffness without significantly increasing thickness while maintaining the existing optical characteristics and reducing shrinkage and expansion due to heat.

Technical Solution

According to an aspect of the disclosure, a liquid crystal display device may include a liquid crystal panel; a light guide plate disposed under the liquid crystal panel; a light source to supply light to the light guide plate; a reflective sheet provided under the light guide plate; a glass fiber coating layer provided on one of an upper surface and a lower surface of the reflective sheet; and a lower chassis disposed under the reflective sheet.

The liquid crystal display device may include a bead coating layer provided between the light guide plate and the reflective sheet.

The glass fiber coating layer may be provided on the lower surface of the reflective sheet, and the bead coating layer may be provided on the upper surface of the reflective sheet.

The glass fiber coating layer may be provided on the upper surface of the reflective sheet, and the bead coating layer may be provided on an upper surface of the glass fiber coating layer.

The light source may include a plurality of light emitting diodes disposed on one side of the light guide plate.

The light source may include a plurality of light emitting diodes disposed under the light guide plate.

The reflective sheet and the glass fiber coating layer may include a plurality of through holes through which the plurality of light emitting diodes pass.

The lower chassis may include at least one beading.

The glass fiber coating layer may be formed of glass fiber pieces and a resin.

The reflective sheet may be formed by mixing glass fiber pieces with any one of polyester terephthalate (PET), polycarbonate (PC), and polyester.

According to another aspect of the disclosure, a liquid crystal display device may include a liquid crystal panel; a light guide plate disposed under the liquid crystal panel; an optical sheet disposed on an upper surface of the light guide plate; a light source to supply light to the light guide plate; a reflective sheet provided under the light guide plate; a glass fiber coating layer provided on a lower surface of the reflective sheet; and a lower chassis disposed under the reflective sheet and having at least one beading.

Advantageous Effects

When a glass fiber coating layer is formed on one surface of the reflective sheet like the reflective sheet of the liquid crystal display device according to an embodiment of the disclosure, stiffness of the reflective sheet may be increased. When the stiffness of the reflective sheet is improved in this way, wrinkle phenomenon of the reflective sheet such as sagging or bending of the reflective sheet may be prevented or reduced. Accordingly, image spot phenomenon of the liquid crystal display device caused by the wrinkle phenomenon of the reflective sheet may be improved.

In addition, when the glass fiber coating layer is formed on one surface of the reflective sheet like the reflective sheet of the liquid crystal display device according to an embodiment of the disclosure, the total thickness of the reflective sheet and the glass fiber coating layer may be reduced compared to increasing the stiffness of the reflective sheet by increasing the thickness of the reflective sheet itself. Therefore, the thickness of the liquid crystal display device may be reduced.

In addition, when the glass fiber coating layer is formed on one surface of the reflective sheet like the reflective sheet of the liquid crystal display device according to an embodiment of the disclosure, a coefficient of thermal expansion may be reduced, so that an expansion space provided around the reflective sheet may be reduced. Accordingly, degree of freedom in designing a width of the bezel of the liquid crystal display device may be increased.

