KR101926528B1 - Backlight unit and lcd including the same - Google Patents

Abstract

The present invention relates to a backlight unit, and more particularly, to a backlight unit including a light source that is turned on and off in units of scanning lines; And a light guide plate disposed to face the light source and converting the point light source into a planar light source, wherein a plurality of first engraved patterns forming a line in the scanning line direction and a plurality of And each of the engraved patterns has a first inclined face for reflecting light incident from the light source in an upward direction and a second inclined face for reflecting light incident from the light source in a lateral direction, , And the light reflected by the second inclined surface of each of the plurality of first engraved patterns is re-reflected to the second inclined surface of the first engraved patterns by the second inclined surface of each of the plurality of second engraved patterns The plurality of second intaglio patterns are arranged to be offset from the plurality of first intaglio patterns adjacent to each other so as to straighten the light.

Description

BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE MODULE INCLUDING THE SAME

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backlight unit, and in particular, to a liquid crystal display apparatus using a scanning backlight system that sequentially drives a plurality of light sources on a backlight unit, a light guide plate having a pattern for increasing the traveling distance and output amount of light And a liquid crystal display device module including the backlight unit.

As information electronic devices for realizing high-resolution and high-quality images such as potable devices such as mobile phones and notebook computers and HDTVs are developed, a flat panel display device ) Are increasingly in demand. As such flat panel display devices, a liquid crystal display (LCD), a plasma display panel (PDP), a field emission display (FED), and an organic light emitting diode (OLED) have been actively studied. However, Liquid crystal displays (LCDs) are in the spotlight at present due to the realization of large-area screens.

Such a liquid crystal display device implements gradation of an image by changing the molecular arrangement of the liquid crystal by applying an electric field, and a draw phenomenon occurs on the screen depending on the response speed of the liquid crystal. Various methods have been proposed to overcome this drawback, As one of such methods, a scanning backlight driving method for sequentially turning on and off the backlight units provided in the liquid crystal display device has been proposed.

1 is a view for explaining a scanning backlight driving method of a conventional liquid crystal display device.

Referring to the drawings, a conventional liquid crystal display device includes a liquid crystal panel 10, at least one light source 20 that can be individually turned on at the side of the liquid crystal panel, and a liquid crystal panel 10 and a light source 20 The LCD panel 10 is divided into a predetermined logical scanning line unit and sequentially driven according to a scanning backlight driving method.

First, when the liquid crystal panel 10 sequentially receives gate signals from the controller 50 to the first to n-th gate signals, the first LED lamp LED1 is turned on and the first scanning line at the corresponding position is driven, Then, the second LED lamp (LED2) is turned on, and at this time, the second scanning line at the corresponding position is driven and the corresponding image is displayed. In this manner, when the first to n-th lamps (LED1 to LEDn) are sequentially turned on, the images are sequentially driven from the first scanning line to the n-th scanning line in synchronism with each other.

If a certain lamp is turned on in the scanning backlight driving method, corresponding data of a scanning line at a position adjacent thereto may be displayed and the quality of the image may be deteriorated. For example, when the second lamp (LED2) is lit, the first and third lamps (LED1, LED3) are blinking, but the image related to the first and third scanning lines is displayed by the second lamp .

According to the above-described problems, it is possible to divide the light guide plate into a predetermined number of pieces to reduce the influence of the light emitted from each LED lamp on the adjacent scanning lines rather than the corresponding scanning lines, or to form a micro lenticular pattern on the light guide plate A method of minimizing the influence between each scanning line has been proposed.

2, the conventional backlight unit includes an LED lamp 20, a light guide plate 30, an optical sheet 41, and a backlight unit 40. The backlight unit includes a light guide plate 30, And a reflection plate 42. A plurality of LED lamps 20 are disposed on one side of the light guide plate 30 and a lenticular pattern 35 is formed on the upper side of the light guide plate 30. Light emitted from the light source 20 through the lenticular pattern 35 is transmitted through the lenticular pattern 35 The light is converged by the lenticular pattern 35 and is output to the upper diffusion sheet 41. [

However, the lenticular pattern 35 on the light guide plate 30 described above causes a moire phenomenon such as a wave pattern on the screen due to the interference between the optical sheets 41 disposed on the upper side.

The lenticular pattern 35 is formed by applying a synthetic resin, which is a raw material of a lenticular pattern, on the light guide plate 30 and pressing the synthetic resin through a roller or the like. Accordingly, a separate pattern forming process is further added, And the manufacturing cost is increased.

SUMMARY OF THE INVENTION The present invention has been conceived to solve the above-mentioned problems, and it is an object of the present invention to provide a backlight scanning driving type liquid crystal display device which sequentially drives a screen, A light guide plate of a backlight unit and a liquid crystal display module including the same.

As described above, the backlight unit according to the preferred embodiment of the present invention includes: a light source that is turned on and off in units of a scanning line; And a light guide plate disposed to face the light source and converting the point light source into a planar light source, wherein a plurality of first engraved patterns forming a line in the scanning line direction and a plurality of first engraved patterns Each of the engraved patterns includes a first inclined surface for reflecting light incident from the light source in an upward direction and a second inclined surface for reflecting light incident from the light source in a lateral direction, The light reflected by the second inclined surfaces of each of the plurality of first engraved patterns is re-reflected to the second inclined surface of the first engraved patterns by the second inclined surfaces of each of the plurality of second engraved patterns Wherein the plurality of second engraved patterns are alternately arranged with respect to the plurality of neighboring first engraved patterns so as to repeatedly direct the light. The.

And the engraved pattern is a prism shape.

The engraved pattern is characterized in that the cross section is one of a triangle, a quadrangle, a semi-circle, an ellipse, and a trapezoid.

And the second inclined surface is at least longer than the first inclined surface.

Wherein the light guide plate further comprises an optical member on the light emitting surface and the reflection surface, the optical member includes: a diffusion sheet for diffusing light emitted from the light guide plate; A plurality of prism sheets for condensing light diffused by the diffusion sheet; And a reflector for reflecting the light emitted from the light guide plate back to the light guide plate.

In order to achieve the above object, a liquid crystal display module according to a preferred embodiment of the present invention includes: a liquid crystal panel; A first inclined surface disposed to face the light source and reflecting light emitted from the light source in the direction of the liquid crystal panel, and a second inclined surface disposed on the lower surface of the liquid crystal panel, A backlight unit including a light guide plate having a plurality of first and second engraved patterns formed on one surface thereof and having a second inclined surface reflecting the light in a vertical direction; And a mechanism structure for mounting the liquid crystal panel and the backlight unit, wherein the plurality of engraved patterns include a plurality of first engraved patterns forming a line in the scanning line direction of the liquid crystal panel, and a plurality of second engraved patterns And the light reflected by the second inclined surface of each of the plurality of first engraved patterns is divided by the second inclined surface of each of the plurality of second engraved patterns into a second inclined surface of the first engraved patterns And the plurality of second engraved patterns are arranged to be offset from the neighboring plurality of the first engraved patterns so that the light is straightened repeatedly.

The mechanism structure includes: a support main body in which the liquid crystal panel is seated inward; A top case coupled to one side of the support main to support and fix the liquid crystal panel and a cover bottom coupled to the other side of the support main and top case to mount the PCB substrate and the optical device member .

According to a preferred embodiment of the present invention, in a backlight scanning driving type liquid crystal display device in which a screen is horizontally divided and sequentially driven, an engraved pattern having a plurality of prismatic shapes formed on the back surface of the light guide plate is formed, And it has an effect of improving the straightness of light emitted from the light source and the light collecting rate.

1 is a view for explaining a scanning backlight driving method of a conventional liquid crystal display device.
2 is a view showing a structure of a backlight unit including a light guide plate having a conventional lenticular pattern.
3 is a view illustrating a backlight unit and its light guide plate according to a first embodiment of the present invention.
4 is a view for explaining the structure of the engraved pattern of the LGP according to the first embodiment of the present invention and the progress of light through the structure.
5 is a view illustrating a backlight unit and its light guide plate according to a second embodiment of the present invention.
FIG. 6 is an exploded perspective view illustrating a structure of a liquid crystal display module including a light guide plate of a backlight unit according to an embodiment of the present invention. FIG.

Hereinafter, a backlight unit and a liquid crystal display module including the same according to a preferred embodiment of the present invention will be described with reference to the drawings.

It is to be understood that the drawings referred to in the description of the embodiments are not intended to limit the shape and position of components to the illustrated form, and in particular, to facilitate understanding of the structure and geometry of the technical features of the present invention, The scale is exaggerated or reduced.

3 is a view illustrating a backlight unit and its light guide plate according to a first embodiment of the present invention. In the following description, an example of the 2-light-emitting type backlight unit in which the light sources are positioned at the lower and both sides of the lower side of the liquid crystal panel has been described. However, the 1-light type backlight unit located only at one end of the liquid crystal panel Configuration can be applied.

As shown in the figure, the backlight unit of the present invention includes a plurality of LED lamps 120a and 120b as point light sources, a light guide plate 130 that converts the point light source into a surface light source, An optical sheet 141 for condensing light, and a reflection plate 142 for reflecting light emitted from the light guide plate 130.

More specifically, a plurality of LED lamps 120a and 120b are disposed on both sides of the liquid crystal display device, and light is incident on a side surface of the light guide plate 130. In accordance with the backlight scanning driving method, And is turned on and off.

The LED lamps 120a and 120b are packaged in a conventional LED semiconductor light emitting device. A plurality of LED semiconductor light emitting devices can be mounted in one package according to the type of the LED package. Although not shown, And may be provided in a form to be bonded.

The light guide plate 130 is disposed on the back surface of the liquid crystal panel (not shown) and is disposed to face the light emitting surfaces of the LED lamps 120a and 120b, The light guide plate 130 receives the light sequentially received from the LED lamps 120a and 120b and guides the light to the respective side ends and guides the light to the front side. In particular, a plurality of prismatic engraved patterns 131 are formed in a row on the back surface of the light guide plate 130, and a plurality of prism pattern lines are staggered from each other between neighboring lines. This intaglio pattern 131 doubles the directivity and the light condensing rate of light passing through the light guide plate 130. Since the engraved pattern 131 is formed on the back surface of the light guide plate 130 and is spaced apart from the optical sheet 141, moire phenomenon due to mutual interference is prevented, The back surface of the light guide plate is patterned by a predetermined cutter, so that it is not necessary to provide a plurality of processing facilities separately prepared. The shape of the engraved pattern 131 may be a semicircle, a quadrangle, an ellipse, a trapezoid, or the like as well as the illustrated prism shape. The detailed structure of the above-mentioned engraved pattern 131 and the direction of light through it will be described in detail later.

A plurality of optical sheets 141 may be further provided on the front surface of the light guide plate 130, that is, between the liquid crystal panel (not shown) and the light guide plate. A plurality of optical sheets 141 are stacked on the front surface of the light guide plate 130, that is, between the liquid crystal panel (not shown) and the light guide plate, and light emitted from the light guide plate 130 is guided to the entire area of the liquid crystal panel And a prism sheet provided on the light guide plate 130 and serving to increase the luminance by concentrating the diffused light emitted from the diffusion sheet in the front direction.

The above-described diffusion sheet is usually composed of a base film made of PET and beads for light diffusion, and the prism sheet is formed with a fine prism pattern for refracting light in the x- and y-axis directions, respectively. Or more.

The reflection plate 142 is disposed on the back surface of the light guide plate 130 and serves to reflect the light passing through the light guide plate 130 toward the back direction of the light guide plate 130 toward the upper direction of the light guide plate 130 .

According to such a configuration, the light guide plate of the backlight unit according to the embodiment of the present invention guides the light sequentially incident on the scanning line unit from the light source in a form that minimizes the influence on other scanning lines and emits the light to the front side. Hereinafter, the structure of the engraved pattern of the light guide plate according to the embodiment of the present invention and the progress of the light through it will be described in detail with reference to the drawings.

4 is a view for explaining the structure of the engraved pattern of the LGP according to the first embodiment of the present invention and the progress of light through the structure.

As shown in the drawing, at least one of the engraved patterns formed on the light guide plate of the present invention may be formed to be irregular or have a plurality of lines at equal intervals, or may be formed as a plurality of engraved patterns 31, 32 are formed in a line and the engraved patterns 31 and 32 may be arranged to be offset from the lines of the adjacent engraved patterns 33. [ The plurality of engraved patterns 31 to 33 are inclined so that all the surfaces are not perpendicular to the horizontal plane at a predetermined angle, and all the inclined surfaces are inclined toward the upper direction, that is, toward the liquid crystal panel (not shown) .

Therefore, of the light incident from the side surface of the light guide plate, the light (a) reaching the first inclined surface of the engraved pattern 31 is reflected upward and is output. The light b reaching the second inclined plane of the engraved pattern 31 is reflected in the lateral direction and is reflected again by the side of the other engraved pattern 33 and then reflected by the side of the other engraved pattern 32 And then proceeds to the other side of the light guide plate.

That is, the first inclined surface of the engraved pattern formed at the lower portion of the light guide plate emits light passing through the light guide plate, and the second inclined surface serves to straighten the light.

Hereinafter, a light guide plate of a backlight unit according to a second embodiment of the present invention will be described with reference to the drawings. In the following description, the structure of the backlight unit except for the light guide plate is the same as that of the first embodiment described above, so a detailed description thereof will be omitted.

5 is a view illustrating a backlight unit and its light guide plate according to a second embodiment of the present invention.

As shown in the figure, the backlight unit of the present invention is a two-light-emitting type, comprising a plurality of LED lamps 220a and 220b as point light sources, a light guide plate (not shown) for converting the point light source into a planar light source and outputting it to the optical sheet 241 An optical sheet 241 for diffusing and condensing the light emitted from the light guide plate 230 and a reflection plate 242 for reflecting the light emitted from the light guide plate 230.

A predetermined engraved pattern 231 is formed on the back surface of the light guide plate 230. At least one of the engraved patterns 231 may be formed in a plurality of irregular or equally spaced lines. Or a plurality of lines are arranged in a staggered manner. Particularly, the above-mentioned engraved pattern 231 is a semicylindrical shape whose arcuate cross-section extends in the longitudinal direction, and the inclined surface opposed to the light source is inclined at a predetermined angle in the horizontal direction.

According to this structure, the semi-cylindrical engraved pattern 231 doubles the straightness of the light passing through the light guide plate 230 and the light collection rate. That is, the semicylindrical engraved pattern 231 exposes light emitted from the LED lamps 220a and 220b provided at both ends of the light guide plate 231 to the upper side, that is, toward the optical sheet 241 Through the second inclined surface to the other side from the light incidence surface of the light guide plate 231 through the second reflection surface.

Therefore, when the light incident sequentially along the scanning line at the scanning backlight driving time of the liquid crystal display device deviates from the scanning line in the inner progress of the light guide plate, the second inclined surface 231 of the engraved pattern 231 included in the other scanning line And then re-enters the first path. As a result, the influence on other scanning lines is minimized, and a higher quality image can be realized.

The semicylindrical engraved pattern 231 is formed on the back surface of the light guide plate 230 and is separated from the upper optical sheet 241 so that the distance from the pattern formed on the optical sheet 241 is increased, The moire phenomenon due to the interference of the magnetic field is prevented.

FIG. 6 is an exploded perspective view illustrating a structure of a liquid crystal display module including a light guide plate of a backlight unit according to an embodiment of the present invention. FIG.

The liquid crystal display module of the present invention includes a liquid crystal panel 100 and a backlight unit 200 for providing light to the liquid crystal panel 100 and includes various mechanical structures 300, 500).

More specifically, the liquid crystal panel 100 includes a liquid crystal layer interposed between the first substrate and the second substrate with a predetermined distance therebetween, and is connected to a control unit (not shown) Lt; / RTI > In addition to the thin film transistor, various wirings and pixel electrodes are formed on the first substrate, and the second substrate is a color filter substrate for displaying RGB primary colors, and a color filter layer and a black matrix (BM) are formed. The driving driver generates a scan signal and a data signal for driving the thin film transistor and a ramp control signal for scanning backlight driving and supplies the generated signal to the liquid crystal panel 100 and the backlight unit 200, respectively.

More specifically, the liquid crystal panel 100 includes a plurality of scan lines and a plurality of data lines arranged perpendicularly and horizontally and defining a plurality of pixel regions, A thin film transistor which is a switching element is formed. The thin film transistor includes a gate electrode connected to the gate line, a semiconductor layer formed by stacking amorphous silicon or the like on the gate electrode, a source electrode formed on the semiconductor layer and electrically connected to the data line and the pixel electrode, Lt; / RTI >

The second substrate includes a color filter composed of a plurality of sub-color filters implementing the colors of red, green and blue, a color filter for separating each sub-color filter and blocking light transmitted through the liquid crystal layer, And a matrix (BM).

The first and second substrates constructed as described above are adhered to each other so as to face each other by a sealant formed on the periphery of the image display area to constitute the liquid crystal panel 100. The first and second substrates are respectively provided with a first polarizing plate and a second polarizing plate, And the second polarizer is attached to the liquid crystal panel 100 to polarize the output light to realize an image.

The support main 300 serves to support and fix the liquid crystal panel 100. Each side end of the liquid crystal panel 100 is seated in a stepped portion formed inside and the inner main surface of the support main 300, The side surface of the liquid crystal panel 100 is closely adhered to the liquid crystal panel 100 so that the rigidity of the liquid crystal display module can be maintained.

The top case 400 is coupled to an upper portion of the support main body 300 on which the liquid crystal panel 100 is mounted and serves to hold the liquid crystal panel 100 without being disturbed by impact applied from the outside. In addition, the top case 400 is fastened to the cover bottom 500 described below in the downward direction.

The backlight unit 200 is disposed on the back surface of the liquid crystal panel 100 to provide light and includes at least one light source and a plurality of optical sheets 100 that efficiently provide light emitted from the light source to the liquid crystal panel 100 through optical compensation. .

In detail, the light source includes a LED package 220, which is a plurality of point light sources, and a lamp substrate 221 to which the LED package 220 is bonded. The LED package 220 includes a scanning line unit And one group is sequentially turned on and blinking.

Although the LED package 220 as a side-view liquid crystal display device is disposed at all the corner edges of the light guide plate 230 in the drawing, it is also possible for the backlight unit to be disposed on both sides of the light guide plate The technical idea of the present invention can be applied.

The optical members are disposed so as to face the light emitting surface of the LED package 220 and provide light to the liquid crystal panel 100. The light guide plate 230 is disposed below the liquid crystal panel 100, And guiding the light emitted from the LED package 220 to the liquid crystal panel 100.

In order to facilitate the progress of the light, the light guide plate 230 is formed so that the light incident from the edge of the light guide 230 is repeatedly reflected and refracted at the upper and lower surfaces of the light guide plate 230, .

At least one engraved pattern 231 having a first inclined surface and a second inclined surface is formed on the back surface of the light guide plate 230 so that light passing through the light guide plate 230 through the first inclined surface is emitted upward, 2 The light advances to the other side straight through the slope.

The optical sheet 241 is provided between the liquid crystal panel 100 and the light guide plate 230 to diffuse and guide the light guided from the light guide plate 230 to the liquid crystal panel 100, And a prism sheet. The diffusion sheet serves to diffuse the light emitted from the light guide plate 230, and the prism sheet functions to condense the light diffused by the diffusion sheet to supply uniform light to the liquid crystal panel 100. The prism sheet includes a first prism sheet and a second prism sheet that are perpendicular to each other in the x- and y-axis directions and refract light in the x- and y-axis directions, So as to improve the straightness.

The reflection plate 242 is provided at a lower portion of the light guide plate 240 and reflects light emitted from the light guide plate 230 in a downward direction, that is, in a direction opposite to the liquid crystal panel 100, do.

Accordingly, the liquid crystal panel 100 described above is mounted on the protruding portion of the inside of the support main 300, and the support main 300 is coupled with the top case 400 to be supported and fixed. After the LED package 220, the light guide plate 230 and other optical members are housed in the cover bottom 500 in the lower direction of the liquid crystal panel 100 and in the support main 300, The liquid crystal display device is completed as one module by being fastened to the support main body 300 and the top case 400.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments.

120a, 120b: LED lamp 130: light guide plate
131: engraved pattern 141: optical sheet
142: Reflector

Claims (7)

A light source that lights and flashes in units of scanning lines; And
And a light guide plate disposed to face the light source and converting the point light source into a surface light source,
Wherein a plurality of first engraved patterns and a plurality of second engraved patterns are formed on the reflective surface of the light guide plate to form one line in the direction of the scanning line in units of the scanning lines,
Each of the engraved patterns has a first inclined surface reflecting the light incident from the light source toward the upper direction and emitting the light, and a second inclined surface reflecting the light incident from the light source in the lateral direction,
The light reflected by the second inclined surfaces of each of the plurality of first engraved patterns is re-reflected to the second inclined surface of the first engraved patterns by the second inclined surfaces of each of the plurality of second engraved patterns Wherein the plurality of second engraved patterns are alternately arranged with respect to the plurality of neighboring first engraved patterns so as to repeatedly advance the light,
And the second inclined surface is at least longer than the first inclined surface. The method according to claim 1,
Wherein the first and second engraved patterns are prism-shaped. The method according to claim 1,
Wherein the first and second engraved patterns are one of a triangle, a quadrangle, a semicircle, an ellipse, and a trapezoid in cross section. delete The method according to claim 1,
The light-
An optical member is further provided on the light exiting surface and the reflecting surface,
Wherein the optical member comprises:
A diffusion sheet for diffusing light emitted from the light guide plate;
A plurality of prism sheets for condensing light diffused by the diffusion sheet; And
And a reflector for reflecting the light emitted from the light guide plate back to the light guide plate. A liquid crystal panel;
A light source that is disposed at a lower portion of the liquid crystal panel and lights and flickers in units of scanning lines; and a light source that is arranged to form one line in units of the scanning lines facing the light source and reflects light irradiated from the light source toward the liquid crystal panel And a second inclined surface for reflecting the light in a direction perpendicular to the direction of the liquid crystal panel, and a light guide plate having a first light-receiving surface and a second light- A backlight unit including the optical member; And
And a mechanism structure for mounting the liquid crystal panel and the backlight unit,
Wherein the plurality of engraved patterns are divided into a plurality of first engraved patterns forming a line in the scanning line direction of the liquid crystal panel and a plurality of second engraved patterns,
The light reflected by the second inclined surfaces of each of the plurality of first engraved patterns is re-reflected to the second inclined surface of the first engraved patterns by the second inclined surfaces of each of the plurality of second engraved patterns Wherein the plurality of second engraved patterns are alternately arranged with respect to the plurality of neighboring first engraved patterns so as to repeatedly advance the light,
And the second inclined surface is at least longer than the first inclined surface. The method according to claim 6,
The mechanism structure includes:
A support main in which the liquid crystal panel is seated inward;
A top case coupled to one surface of the support main body to support and fix the liquid crystal panel,
And a cover bottom coupled to the other side of the support main body and the top case to mount the light source, the light guide plate, and the optical member.

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