KR102002458B1 - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a narrow bezel liquid crystal display.
A liquid crystal display device according to the present invention includes a liquid crystal panel and a backlight unit provided on a back surface of the liquid crystal panel, the backlight unit including a light guide plate for refracting and reflecting light from a plurality of LEDs to provide a surface light source to the liquid crystal panel And an ink pattern for reflecting light to the inside of the light guide plate at a position corresponding to the plurality of LEDs on the first side facing the plurality of LEDs in the light guide plate.
Accordingly, it is possible to implement a narrow bezel and realize a liquid crystal display device displaying a uniform image quality.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display, and more particularly to a narrow bezel liquid crystal display.

A liquid crystal display device (LCD), which is advantageous for moving picture display and has a large contrast ratio and is actively used in TVs and monitors, exhibits optical anisotropy and polarization properties of a liquid crystal, And the like.

Such a liquid crystal display device has a liquid crystal panel in which a liquid crystal panel is interposed between two adjacent substrates through a liquid crystal layer as an essential component and changes the alignment direction of the liquid crystal molecules in an electric field in the liquid crystal panel to realize a difference in transmittance do.

However, since the liquid crystal panel does not have its own light emitting element, a separate light source is required to display the difference in transmittance as an image. To this end, a backlight unit having a light source is disposed on the back of the liquid crystal panel.

The backlight unit is divided into a direct type and an edge type according to the position of the light source. The backlight unit of the direct-type type has a structure in which a light source is disposed under the liquid crystal panel, In the backlight unit of the side-type system, a light guide plate is disposed under the liquid crystal panel, and a light source is disposed on at least one side of the light guide plate so that light emitted from the light source is indirectly reflected To the liquid crystal panel.

Fluorescent lamps such as a cold cathode fluorescent lamp (CCFL) and an external electrode fluorescent lamp (EEFL) have been widely used as a light source of such a backlight unit. However, recently, a thin and lightweight liquid crystal display Light emitting diodes (LEDs), which have advantages in terms of power consumption, weight, and brightness, have been replacing fluorescent lamps with trends.

Particularly, the side-type backlight unit is easier to manufacture than a direct-type backlight unit, has a thin shape, is light in weight, has low power consumption, and is in use.

On the other hand, in recent years, the liquid crystal display device has been widely used, such as a desktop computer monitor and a wall-mounted television, as well as a portable computer, and has been studied for a liquid crystal display device having a wide bezel width Is actively proceeding.

However, the side-type backlight unit has a problem in that the light source is disposed on the side surface as well as the light source and the light guide plate are spaced apart from each other by a certain distance, thereby realizing a narrow-bezel liquid crystal display device.

Also, even if the width of the bezel is reduced by minimizing the distance between the light source and the light guide plate, a hot spot phenomenon occurs in which light is unevenly displayed on the boundary screen of the display area where the image is displayed.

Accordingly, it is an object of the present invention to provide a narrow bezel liquid crystal display device having uniform image quality by forming an ink pattern in a light-incident portion corresponding to a plurality of LEDs.

Another object of the present invention is to provide a liquid crystal display device in which brightness is improved by providing a reflective member for reflecting light on a side portion of the light guide plate excluding the light entrance portion, in particular, a side facing the light entrance portion.

According to an aspect of the present invention, there is provided a liquid crystal display comprising: a liquid crystal panel; And a backlight unit provided on a back surface of the liquid crystal panel, the backlight unit including a light guide plate for providing a surface light source to the liquid crystal panel by refracting and reflecting light from a plurality of LEDs, And an ink pattern for reflecting the light to the inside of the light guide plate at each corresponding position between the plurality of LEDs.

Here, the second side facing the first side of the light guide plate is provided with a reflecting member for reflecting outwardly directed light to the inside of the light guide plate.

Further, the light guide plate may further include the reflective member on third and fourth side portions vertically connecting the first and second side portions.

An engraved pattern for applying the ink pattern is formed on a first side of the light guide plate, and the engraved pattern is formed by a printing method, an injection method, an extrusion method, a pressing method, an imprinting method using a mold such as a stamper, ) Method and a laser processing method using a laser beam.

According to the liquid crystal display device of the present invention, an ink pattern is formed at a position corresponding to a plurality of LEDs among the light-incident portions of the light guide plate facing a plurality of LEDs, and the light is reflected to the inside except for the light- It is possible to improve the luminance of the dark region where the light emitted from each of the plurality of LEDs does not reach, thereby realizing a uniform planar light source.

Accordingly, the width of the bezel is reduced to a minimum, the narrow bezel is implemented, and the narrow bezel is implemented, thereby preventing the hot spot phenomenon occurring at the boundary of the display area of the liquid crystal display device.

1 is an exploded perspective view of a liquid crystal display device according to a preferred embodiment of the present invention.
FIGS. 2A and 2B are cross-sectional views of a liquid crystal display according to a preferred embodiment of the present invention;
3 is a plan view of a light guide plate and a part of an LED assembly according to a preferred embodiment of the present invention.
4A and 4B illustrate an ink pattern formed on a light-incident portion of a light guide plate according to a preferred embodiment of the present invention.
5A is a sectional view of a liquid crystal display device according to another preferred embodiment of the present invention.
5B is a sectional view of a liquid crystal display according to another preferred embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is an exploded perspective view of a liquid crystal display device according to a preferred embodiment of the present invention, and FIGS. 2a and 2b are cross-sectional views illustrating a liquid crystal display device according to a preferred embodiment of the present invention.

1, the liquid crystal display 100 includes a liquid crystal panel 110, a backlight unit 120, a support main body 130 for modularizing the liquid crystal panel 110 and the backlight unit 120, A bottom cover 150, and a top cover 140.

The liquid crystal panel 110 is a part that plays a key role in image display and is composed of a first substrate 112 and a second substrate 114 which are bonded to each other with a liquid crystal layer interposed therebetween.

Although not shown in the drawing, a plurality of gate lines and data lines cross each other on the inner surface of a first substrate 112, which is usually referred to as a lower substrate or an array substrate, on the premise of an active matrix system, pixels are defined, And a thin film transistor (TFT) is provided and connected in a one-to-one correspondence with the transparent pixel electrode formed in each pixel.

On the inner surface of the second substrate 114 called an upper substrate or a color substrate, a color filter of red (R), green (G), and blue (B) A black matrix for covering non-display elements such as a gate line, a data line and a thin film transistor, and a transparent common electrode covering the gate lines and the data lines. Here, the transparent common electrode may be formed on the first substrate 112.

The first and second polarizers 119a and 119b selectively transmit only specific light to the outer surfaces of the first and second substrates 112 and 114, respectively.

A printed circuit board 118 is connected to at least one edge of the liquid crystal panel 110 via a connection member 116 such as a flexible circuit board or a tape carrier package (TCP) To the side of the support main body 130 or to the back surface of the cover bottom 150, as shown in FIG.

When the thin film transistor selected for each gate line is turned on by the on / off signal of the gate driving circuit transmitted through the printed circuit board 118, the liquid crystal panel 110 having the above- The signal voltage is transmitted to the corresponding pixel electrode through the data line, and the alignment direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode.

On the rear surface of the liquid crystal panel 110, a backlight unit 120 is provided to supply light so that the difference in transmittance can be displayed as an image.

The backlight unit 120 includes a light source arranged along the edge of the support main body 130, a reflection plate 125, a light guide plate 123 mounted on the reflection plate 125, and a plurality of optical sheets (121).

The LED 129a is used as a light source. The plurality of LEDs 129a are spaced apart from each other by a predetermined distance and mounted on a printed circuit board (PCB) 129b, thereby forming an LED assembly 129.

The LED assembly 129 is positioned such that the light emitted from the plurality of LEDs 129a faces the first side 123a of the light guide plate 123,

Accordingly, the light emitted from the plurality of LEDs 129a of the LED assembly 129 is indirectly supplied to the liquid crystal panel 110 by using the refraction and reflection of the light guide plate 123.

Here, a heat sink (not shown) may be provided on the rear surface of the LED assembly 129 to more efficiently discharge heat generated from each of the plurality of LEDs 129a. The heat sink (not shown) And may be a flat or bent shape that is positioned on the rear surface of the printed circuit board 129b or that is bent vertically to cover one side of the LED 129a and the back surface of the printed circuit board 129b.

In addition, the printed circuit board 129b may correspond to a metal core printed circuit board having a heat dissipating function.

The reflection plate 125 reflects light passing through the back surface of the light guide plate 123 in a rectangular plate shape toward the liquid crystal panel 110, thereby improving the brightness of light.

The light guide plate 123 guides light emitted from each of the plurality of LEDs 129a to serve as a high-quality surface light source.

The first side 123a of the light guide plate 123 is spaced apart from the plurality of LEDs 129a by a first gap G. The first side 123a of the light guide plate 123 is partially provided with a plurality of ink patterns 210 are provided.

As shown in FIG. 2B, the plurality of ink patterns 210 are formed at corresponding positions between the plurality of LEDs 129a, thereby improving the brightness of the dark region in the light guide plate 123. FIG. The ink pattern 210 will be described later in detail.

The light guide plate 123 is further provided with a reflective member 180 for preventing light from leaking to the second side 123b facing the first side 123a.

The reflective member 180 may be a plate made of a material capable of reflecting light, an adhesive tape, or a reflective film formed by applying ink. Here, when the reflective member 180 is a plate, it may be formed integrally with the reflective plate 125 provided on the back surface of the light guide plate 123.

The reflection member 180 is attached to the second side portion 123b facing the first side portion 123a of the light guide plate 123 so as to be incident on the second side portion 123b through the first side portion 123a, Can be reflected toward the inside of the light guide plate 123 by the reflection member 180.

The reflective member 180 is provided only on the second side portion 123b opposite to the first side portion 123a. However, the reflective member 180 is not limited to the reflective member 180 May be provided.

The light guide plate 123 may be made of polymethyl methacrylate (PMMA) or polymethacrylic styrene (MS) resin in which polymethyl methacrylate (PMMA) and polystyrene (PS) are mixed. have.

A back surface pattern 220 for guiding light is formed on the back surface of the light guide plate 123. The back surface pattern 220 is formed on the back surface of the light guide plate 123 so that light emitted from each of the plurality of LEDs 129a can be widely diffused, 123a of the first section A2 except for the first section A1.

The plurality of optical sheets 121 interposed on the light guide plate 123 diffuse or condense the light converted into the surface light source by the light guide plate 123 so that a more uniform surface light source is incident on the liquid crystal panel 110 .

The plurality of optical sheets 121 may include a diffusion sheet for diffusing light, a prism sheet for condensing light, and a protective sheet for protecting the prism sheet and serving as an auxiliary for diffusing light.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the top cover 140, the support main body 130, and the cover bottom 150.

The support main body 130 has a rectangular shape and includes a vertical part 132 surrounding the edges of the liquid crystal panel 110 and the backlight unit 120 and a vertical part 132 extending from the inside of the vertical part 132, And a horizontal portion 134 separating the liquid crystal panel 110 and the backlight unit 120 while supporting the back edge.

The top cover 140 has a rectangular shape with a cross section bent in a shape so as to cover a front edge of the liquid crystal panel 110 and a side portion of the support main 130, To be displayed.

The cover bottom 150 which is the base of the whole structure of the liquid crystal display device 100 with the backlight unit 120 mounted thereon has a bottom plate 152 in the shape of a rectangular plate and a side plate 152 perpendicular to the bottom plate 152, (154).

The liquid crystal panel 110 and the backlight unit 120 are covered with the top cover 140 covering the top edge of the liquid crystal panel 110 in a state where the liquid crystal panel 110 and the backlight unit 120 are surrounded by the support main body 130, And the cover bottoms 150 covering the back surface are coupled to each other at the front and rear sides to be integrated through the support main body 130 to be modularized.

The light emitted from each of the plurality of LEDs 129a of the backlight unit 120 is incident on the first side portion 123a of the light guide plate 123 and then is directed toward the liquid crystal panel 110 Refracted, and processed into a more uniform high-quality surface light source while being passed through the plurality of optical sheets 121 together with the light reflected by the reflection plate 125, and then supplied to the liquid crystal panel 110.

Here, the top cover 140 may be referred to as a case top or a top case, and the support main 130 may be referred to as a guide panel or a main support or a mold frame, and the cover bottom 150 may be referred to as a bottom cover.

FIG. 3 is a plan view of a light guide plate and a part of an LED assembly according to a preferred embodiment of the present invention. FIGS. 4A and 4B illustrate an ink pattern formed on a light-incident portion of a light guide plate according to a preferred embodiment of the present invention. 1, Figs. 2A and 2B.

Light emitted directly from each of the plurality of LEDs 129a is referred to as a first light 11 and light reflected from the first light 11 is referred to as a second light 12.

3, the light guide plate 123 is disposed such that the first side portion 123a and the plurality of LEDs 129a of the LED assembly 129 are spaced apart from each other by a first gap G. As shown in FIG.

Here, the first gap G is the minimum gap for the narrow bezel.

Although not shown in the drawing, a plurality of LEDs 129a may be provided to prevent the light guide plate 123 from expanding between the plurality of LEDs 129a and the first side portion 123a of the light guide plate 123 corresponding thereto, The plurality of LEDs 129a and the first side portions 123a of the light guide plate 123 may be in contact with each other and the first gap G may be zero.

The first side 123a of the light guide plate 123 is partially provided with a plurality of ink patterns 210 for guiding light incident into the light guide plate 123. The plurality of ink patterns 210 may include a plurality of And to improve the brightness of a dark region m formed at corresponding positions between the LEDs 129a so that light from each of the plurality of LEDs 129a does not reach.

The first light 11 emitted from the plurality of LEDs 129a is incident into the light guide plate 123 through the first side portion 123a of the light guide plate 123 and is refracted and reflected, At this time, some of the first light 11 incident on the light guide plate 123 is refracted or reflected in the direction toward the first side 123a. The second light 12 thus refracted or reflected is reflected back into the light guide plate 123 by the plurality of ink patterns 210 according to the present invention, thereby improving the brightness.

Particularly, since the plurality of ink patterns 210 are formed at positions corresponding to each other among the plurality of LEDs 129a, the dark areas of the light guide plate 123, which is an area where light emitted from each of the plurality of LEDs 129a does not reach, m < / RTI >

The plurality of ink patterns 210 may be formed in an elliptical shape or a circular shape as shown in FIG. 4A, or may be formed in various shapes such as a rectangular shape, a square shape, or the like as shown in FIG. 4B.

At this time, the plurality of ink patterns 210 may be provided on the first side portion 123a corresponding to a position between the plurality of LEDs 129a in a state of being spaced apart from each other, 1 side 123a.

The ink pattern 210 may be formed by printing a white or silver ink having good reflection characteristics. The ink pattern 210 may be formed by adjusting the viscosity of the ink by adjusting the constituent components (mixing ratio) of the ink, So that the reflectance of light can be controlled.

The second side portion 123b of the light guide plate 123 is provided with a reflective member 180 for reflecting light.

The reflective member 180 reflects the light toward the second side portion 123b through the first side portion 123a of the light guide plate 123 toward the inside of the light guide plate 123, thereby improving the brightness of the light.

The luminance of the light output area and the dark area m where the light emitted from the plurality of LEDs 129a reaches through the ink pattern 210 and the reflective member 180 becomes uniform, It is possible to realize a uniform planar light source.

The back surface of the light guide plate 123 has a first section A1 as a section from the first side 123a to a certain distance and a second section A2 as a back pattern (220 of FIG. .

2A and 2B) is not formed so that the light emitted from each of the plurality of LEDs 129a can be refracted and reflected and travel in the light guide plate 123. In the first section A1, to be.

The second section A2 is a section in which the back pattern (220 in Figs. 2A and 2B) is formed as a whole.

2A and 2B) serves to emit light incident from each of the plurality of LEDs 129a to the front surface of the light guide plate 123. [

The back surface pattern 220 may be formed in a convex or concave shape by a printing method or an injection method and may be a circular pattern, an elliptical pattern, a polygon pattern, Pattern (hologram pattern) and so on.

At this time, although not shown in the drawings, the rear pattern 220 may be formed such that the distance between the patterns becomes uniform as the distance from the plurality of LEDs 129a, which are light sources, is increased, but the pattern size increases. Or the plurality of LEDs 129a, the pattern density is uniform, but the pattern density is made smaller as the distance between the patterns is decreased, and the pattern density is increased as the distance from the light source is increased. have.

The ink pattern formed on the light-incident portion of the light guide plate may be formed in various structures. This will be described in detail with reference to the drawings.

FIG. 5A is a cross-sectional view of a liquid crystal display according to another embodiment of the present invention, and FIG. 5B is a cross-sectional view of a liquid crystal display according to another preferred embodiment of the present invention. Here, the configuration except for the structure of the ink pattern formed on the first side of the light guide plate is the same as that of FIGS. 1, 2A, and 2B, and therefore, the same reference numerals are assigned to the same components, and a description thereof will be omitted.

5A, ink is applied to a plurality of engraved patterns formed at positions corresponding to a plurality of LEDs 129a among the first side portions 123a of the light guide plate 123, . In this case, unlike the ink pattern 210 shown in FIG. 2A, the ink pattern 310 does not protrude from the outer surface of the first side portion 123a of the light guide plate 123.

A plurality of intaglio patterns formed on the first side 123a of the light guide plate 123 may be formed by a printing method, an injection method, an extrusion method, a pressing method, an imprinting method using a mold such as a stamper, Or the like.

5B, the ink pattern 410 may be formed by applying ink to each of the positions corresponding to a plurality of LEDs 129a among the first side portions 123a of the light guide plate 123. As shown in FIG. Or the ink pattern 410 may be formed by applying ink to the engraved pattern formed at each corresponding position between the first side 123a of the light guide plate 123 and the plurality of LEDs 129a.

As described above, according to the present invention, the ink pattern is partially provided on the first side portion of the light guide plate for improving the brightness of the dark region, and by providing the reflective member on the second side facing the first side, It is possible to provide a liquid crystal display device which realizes a liquid crystal display device.

In particular, by applying the ink pattern and the reflective member according to the present invention, it is possible to realize a narrow bezel liquid crystal display device and realize a liquid crystal display device having a uniform image quality.

The embodiments of the present invention as described above are merely illustrative, and those skilled in the art can make modifications without departing from the gist of the present invention. Accordingly, the protection scope of the present invention includes modifications of the present invention within the scope of the appended claims and equivalents thereof.

110: liquid crystal panel 121: multiple optical sheets
123: light guide plate 123a (first side portion, 123b: second side)
125: Reflector 129: LED assembly
180: reflection member 210, 310, 410: reflection pattern

Claims (4)

A liquid crystal panel;
And a backlight unit provided on a back surface of the liquid crystal panel, the backlight unit including a light guide plate for providing a planar light source to the liquid crystal panel by refracting and reflecting light from a plurality of LEDs,
In the light guide plate, the first side facing the plurality of LEDs
And an ink pattern for reflecting light to the inside of the light guide plate at each corresponding position between the plurality of LEDs,
Wherein the back surface of the light guide plate is divided into a first section that is a section from the first side section to a predetermined distance and a second section that is a section from an end of the first section to a second side facing the first side section, A back surface pattern is formed in the second section,
Wherein an engraved pattern protruding to the inner surface of the first side of the light guide plate is formed at each position corresponding to the plurality of LEDs, the ink pattern is applied to the engraved pattern,
A protective means for protecting the plurality of LEDs is provided between the plurality of LEDs and a first side of the light guide plate corresponding thereto,
Wherein a distance between the back patterns is uniform and a size of the back pattern increases as the LEDs are further away from the plurality of LEDs, and the back pattern is formed inside the light guide plate.
The method according to claim 1,
On the second side facing the first side of the light guide plate
And a reflective member for reflecting the light toward the inside of the light guide plate.
3. The method of claim 2,
The light-
And the reflective member is provided on third and fourth sides that vertically connect the first and second sides.
The method according to claim 1,
The engraved pattern
A liquid crystal display device formed by one of a printing method, an injection method, an extrusion method, a pressing method, an imprinting method using a mold such as a stamper, and a laser processing method using a laser beam.

Images