KR20150037237A - Liquid crystal display device having light emitting device back light unit - Google Patents

Abstract

The present invention relates to a liquid crystal display device capable of being light and thin and having easy assembly. The device includes a liquid crystal panel which display an image; a light guide plate which is arranged in the lower part of the liquid crystal panel, guides light, and supplies the same to the liquid panel; an LED substrate which is arranged on a side of the light guide plate and has multiple LEDs which emit light to the light guide plate; a guide panel which supports the liquid crystal panel in the front side and assembles the light guide plate and the LED substrate; an LED flexible circuit board which has one end connected to the LED substrate and the other end connected to the outside and transmits a signal to the LED; and a guide groove which is formed on the back side of the guide panel and receives the LED flexible circuit board.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a liquid crystal display (LCD)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device having an LED backlight structure, and more particularly to an L liquid crystal display device capable of minimizing thickness and reducing manufacturing cost.

2. Description of the Related Art In recent years, flat panel display devices such as liquid crystal display devices (LCDs), which are used only for light and small, have been used in various electronic devices such as mobile phones, tablet computers, .

Such a liquid crystal display element is a transmissive display element, and displays a desired image on the screen by controlling the amount of light transmitted through the liquid crystal layer by refractive index anisotropy of liquid crystal molecules. Therefore, in a liquid crystal display element, a back light, which is a light source that transmits the liquid crystal layer for displaying an image, is provided. Generally, the backlight can be roughly divided into two types.

First, a light source is provided on a side surface of a liquid crystal panel to provide a light to a liquid crystal layer, and a second type is a direct light type backlight in which a light source provides light directly below the liquid crystal panel.

In the side-type backlight, a light source is provided on a side surface of the liquid crystal panel, and light can be supplied to the liquid crystal layer through the reflection plate and the light guide plate. Therefore, since the thickness can be made thinner, it is mainly used for a notebook or the like requiring a thin display device. However, since the light source for emitting light is located on the side surface of the liquid crystal panel, the side-type backlight is difficult to apply to a large-area liquid crystal panel, and light is supplied through the light guide plate. Therefore, there has been a problem in that it is not suitable for large-area liquid crystal panel for LCD TV, which has recently been spotlighted.

The direct-type backlight is mainly used for manufacturing a liquid crystal panel for LCD TV since light emitted from a light source is directly supplied to a liquid crystal layer and thus can be applied not only to a large-area liquid crystal panel but also to a high-

Meanwhile, in recent years, a light source that emits light by itself such as a light emitting device instead of a fluorescent lamp has been used as a light source of a backlight. Since the light emitting device emits R, G, and B monochromatic light, the color reproduction ratio is good when applied to a backlight and the driving power can be reduced.

FIG. 1 is a cross-sectional view schematically illustrating a structure of a conventional liquid crystal display device having a backlight having the above-described light emitting device.

 1, the liquid crystal display element includes a first substrate 1 and a second substrate 3, and a liquid crystal layer (not shown) between the first substrate 1 and the second substrate 3 and implements an image as a signal is applied from the outside An LED 52 provided with a liquid crystal panel 10 and a light emitting device disposed on a lower side of the liquid crystal panel 10 to emit light and an LED substrate 52 on which a plurality of LEDs 52 are mounted A light guide plate 20 disposed at a lower portion of the liquid crystal panel 10 to guide the light emitted from the LED 52 to the liquid crystal panel 10, A diffusing sheet 32 provided between the light guide plate 20 and diffusing the light supplied to the liquid crystal panel 10 and a prism sheet 32 disposed on the diffusion sheet 32 to condense the diffused light, A reflection plate 27 disposed below the light guide plate 20 and reflecting the light input to the lower portion to the liquid crystal panel 10, A light guiding plate 20 and a guiding panel 25 for supporting the liquid crystal panel 10 and a light guiding plate 25 positioned below the guiding panel 25 and supporting the liquid crystal panel 10, the light guide plate 20, the diffusion sheet 32, A liquid crystal panel 10, a light guide plate 20, a diffusion sheet 32, and a prism sheet 32, which are combined with the lower cover 40 to form a prism sheet 34 and a guide panel 25, 34, and an upper cover 42 for supporting the guide panel 25.

Although not shown in the drawing, a plurality of pixels are provided on the first substrate 1 of the liquid crystal panel 10, pixel electrodes and thin film transistors are formed in each pixel, and common electrodes are formed on the second substrate 3 When an external signal is applied through the thin film transistor, an electric field is formed in the liquid crystal layer to control the alignment of the liquid crystal molecules to control the amount of light transmitted through the liquid crystal layer to realize an image. At this time, a polarizing plate (not shown) is attached to the first substrate 1 and the second substrate 3, respectively, to control the polarization direction of the light incident on the liquid crystal layer and the light output from the liquid crystal layer.

However, the following problems arise in the above-described liquid crystal display element. As shown in the figure, in the conventional liquid crystal display element, the liquid crystal panel 10, the light guide plate 20, the optical sheet, and the like are supported by the guide panel 25, And the upper cover 42, respectively. Unlike the liquid crystal panel 10, the light guide plate 20 and the optical sheet, the guide panel 25, the lower cover 40 and the upper cover 42 are not essential components for driving the liquid crystal display elements, It is a necessary configuration to assemble. Further, since the guide panel 25, the lower cover 40 and the upper cover 42 are relatively heavy and thick compared to other configurations, there is a problem in making the liquid crystal display device thin and light.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a liquid crystal display device which is lightweight, thin, and easy to assemble.

According to an aspect of the present invention, there is provided a liquid crystal display device including: a liquid crystal panel in which an image is formed; A light guide plate disposed under the liquid crystal panel and guiding light to supply the light to the liquid crystal panel; An LED substrate disposed on one side of the light guide plate and having a plurality of LEDs for emitting light to the light guide plate; A guide panel supporting the liquid crystal panel on the front surface and assembling the light guide plate and the LED substrate; An LED flexible circuit board having one end connected to the LED substrate and the other end connected to the outside to transmit a signal to the LED; And a guide groove formed on a back surface of the guide panel and housing the LED flexible circuit board.

Wherein the guide panel is formed on the front surface and on which the LED substrate is mounted; And

And a LED flexible circuit board connected to the LED substrate mounted on the substrate seating part, the LED flexible circuit board including a guide hole passing through the back surface, the substrate seating part on the front surface of the guide panel and the guide grooves on the back surface are vertically arranged, The LED flexible circuit board, which is inserted and penetrated to the rear surface of the guide panel, is folded vertically once at the back surface, and then disposed in the guide groove.

In the present invention, the thickness of the liquid crystal display element can be minimized and weight can be reduced by eliminating the lower cover of the liquid crystal display element and directly attaching the light guide plate to the lower portion of the guide panel. Further, in the present invention, the LED flexible printed circuit board for supplying a signal to the LED is housed in a guide groove formed on the back surface of the guide panel, thereby simplifying the assembly of the liquid crystal display device.

1 is a sectional view showing the structure of a conventional liquid crystal display device;
2 is a schematic plan view showing the structure of a liquid crystal display element according to the present invention.
3 is a sectional view taken along the line I-I 'of FIG. 2;
4 is a sectional view taken along line II-II 'of FIG.
5 is a partially enlarged perspective view of a guide panel according to the present invention.
6A to 6E are views showing the assembling of the LED flexible circuit board in the liquid crystal display element according to the present invention.

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

2 is a plan view schematically showing the structure of a liquid crystal display element according to the present invention. 2, the liquid crystal display of the present invention includes a liquid crystal panel 110, a plurality of flexible printed circuits 162 attached to one side pad region of the liquid crystal panel 110, An LED substrate 150 mounted on the other side of the panel on which a plurality of LEDs are mounted and an LED flexible circuit board 164 connected to the LED substrate 150 to apply a signal to the LEDs.

Although not shown in the drawing, the liquid crystal panel 110 includes a first substrate and a second substrate. Since the area of the first substrate is larger than that of the second substrate, when the first substrate and the second substrate are cemented A pad region in which the first substrate is exposed to the outside is formed. A plurality of flexible printed circuit boards (162) are attached to the pad area with a predetermined distance therebetween to apply an external signal to the liquid crystal panel (110).

The LED substrate 150 is formed with various wirings and is electrically connected to a plurality of LEDs mounted thereon. In addition, the LED flexible circuit board 164 is attached to the pad area after one end thereof is bonded to the LED substrate 150 and then extended to the pad area. When wiring is formed in the LED flexible circuit board 164 and the LED flexible circuit board 164 is attached to the LED substrate 150, the wiring of the LED flexible circuit board 164 is electrically connected to the wiring of the LED substrate 150 And an external LED signal is applied to the LED via the LED flexible substrate 164 and the LED substrate 150, so that the LED emits light.

In the conventional liquid crystal display device shown in FIG. 1, the LEDs are disposed on both sides of the liquid crystal panel so that light is supplied to the liquid crystal panel from both sides. In contrast, in the present invention, the LEDs are formed in the opposite regions of the pad regions, , Wherein the supply of the signal to the LED is accomplished by an LED flexible printed circuit board (164) extending from the pad area to the LED substrate (150).

The liquid crystal display element having the above-described structure will be described in more detail with reference to FIGS. 3 and 4. FIG.

3 is a cross-sectional view taken along line I-I 'of FIG. 2, illustrating a structure of a pad region of a liquid crystal panel and a region where LEDs are arranged. As shown in FIG. 3, the liquid crystal display according to the present invention includes a liquid crystal panel 110 and a backlight. The liquid crystal panel 110 includes a first substrate 101 and a second substrate 103, and a liquid crystal layer (not shown) between the first substrate 101 and the second substrate 103, and implements an image as a signal is applied from the outside.

The backlight includes an LED substrate 150 disposed on a lower side surface of the liquid crystal panel 110 and having a plurality of LEDs 152 mounted thereon for emitting light and an LED 152 disposed below the liquid crystal panel 110, A light guide plate 120 for guiding the emitted light to the liquid crystal panel 110 and a light guide plate 120 provided between the liquid crystal panel 110 and the light guide plate 120 to be guided from the light guide plate 120 to be supplied to the liquid crystal panel 110 And a reflector 140 disposed below the light guide plate 120 and reflecting the light guided to the lower portion of the light guide plate 120. The optical sheet 130 includes a diffusion sheet and a prism sheet.

The optical sheet 130 is supported by the guide panel 125 and the LED substrate 150 is attached to the guide panel 125 and the reflection plate 140 is attached to the light guide plate 120. An upper cover 149 is placed on the upper edge region of the liquid crystal panel 110. The upper cover 149 is coupled to the guide panel 125 to thereby assemble the liquid crystal panel 110 and the backlight, do.

Though not shown in the figure, a plurality of gate lines and data lines are vertically and horizontally arranged on the first substrate 101 to define a plurality of pixel regions, and a thin film transistor serving as a switching element is formed in each pixel region A pixel electrode formed on the pixel region is formed. The thin film transistor includes a gate electrode connected to a gate line, a semiconductor layer formed by stacking amorphous silicon or the like on the gate electrode, and a source electrode and a drain electrode formed on the semiconductor layer and connected to the data line and the pixel electrode .

As shown in the drawing, a driving device 105 such as a gate driving IC or a data driving IC may be mounted on the first substrate 101 of the pad region, (107) is attached to the pad region of the first substrate (101).

Although not shown in the figure, a metal wiring is formed in the pad region of the first substrate 101 and electrically connected to the driving element 105. When the metal wiring is also formed on the flexible circuit board 107 so that the flexible circuit board 107 is attached to the pad area of the first substrate 101, And the external signal is applied to the driving element 105 through the metal wiring of the flexible circuit board 107 and the metal wiring of the first substrate 101. [

In addition, the driving element 105 outputs a scanning signal or an image signal in accordance with an input signal and supplies the scanning signal or the image signal to the pixel region through a gate line or a data line.

The second substrate 102 includes a color filter composed of a plurality of sub-color filters embodying colors of red (R), green (G) and blue (B) And a black matrix for blocking light passing through the liquid crystal layer.

The first substrate 101 and the second substrate 102 constituted as described above are adhered to each other by a sealant (not shown) formed on the periphery of the image display region to constitute a liquid crystal panel, and the first substrate 101 (Not shown) formed on the first substrate 101 or the second substrate 102. As shown in FIG.

Although not shown in the drawing, a first polarizer and a second polarizer are attached to the first substrate 101 and the second substrate 102, respectively, to polarize light input to and output from the liquid crystal panel 110, .

The light guide plate 120 is for guiding the light input from the LED 152 to the liquid crystal panel 110. The light incident on one side of the light guide plate 120 is reflected by the upper surface and the lower surface of the light guide plate 120, And then output to the outside of the light guide plate 120. [ At this time, the light guide plate 120 is made of a rectangular parallelepiped, and a pattern or groove may be formed on the bottom surface thereof to scatter incident light.

The reflection plate 140 is disposed below the light guide plate 120 and extends to the lower portion of the guide panel 125 so that the reflection plate 140 is fixed to the lower surface of the guide panel 125 by the double- . At this time, an adhesive may be applied instead of the double-sided tape 142 as an adhesive means for adhering the reflector 140 to the lower surface of the guide panel 125. Further, although not shown in the drawing, the reflection plate 140 may be fixed to the lower surface of the light guide plate 120 by an adhesive means.

The optical sheet 130 is supplied to the liquid crystal panel 110 by improving the efficiency of light output from the light guide plate 120. The optical sheet 130 includes a diffusion sheet for diffusing light output from the light guide plate 120 and two prism sheets for condensing light diffused by the diffusion sheet to supply uniform light to the liquid crystal panel 110. [ . At this time, the prisms of the two prism sheets are formed so as to cross vertically in the x and y directions, respectively, so that light is refracted in the x and y directions to improve the linearity of the light.

The plurality of LEDs 152 are disposed along one side of the liquid crystal panel 110. In the present invention, the LED 152 is disposed on the opposite side of the pad region to which the flexible circuit board 107 is attached. The plurality of LEDs 152 are mounted on the LED substrate 150 and the LEDs 152 are mounted on the upper surface of the guide panel 125. Therefore, the LEDs 152 are arranged in the upper direction and are not disposed toward the liquid crystal panel 110, but are arranged in the lower direction to face the guide panel 125 and the light guide plate 120 As shown in Fig. At this time, the LED substrate 150 is attached to the guide panel 125 by an adhesive means such as an adhesive tape or an adhesive.

As the LED 152, R, G, and B LEDs that emit red light, G (green), and B (blue) monochromatic light, or LED devices that emit white light may be used.

When monochromatic LEDs emitting monochromatic light are arranged, monochromatic LEDs of R, G, and B are alternately arranged at regular intervals to mix monochromatic light emitted from the LEDs into white light and then to the liquid crystal panel 110, A plurality of LED elements are arranged at regular intervals to supply white light to the liquid crystal panel 110. [

The white light LED device comprises a blue LED that emits blue light and a phosphor that emits yellow light by absorbing blue monochromatic light. The blue monochromatic light output from the blue LED and the yellow monochromatic light emitted from the phosphor are mixed to form a liquid crystal And is supplied to the panel 110.

In FIG. 3, reference numeral 156 denotes a step prevention pad, which is formed to remove a step between the upper surface of the liquid crystal panel 110 and the LED substrate 150, thereby preventing a failure due to a step difference during assembly. At this time, the pad 156 is bonded to the LED substrate 150 by a bonding means 157 such as a double-sided tape or an adhesive layer.

4 is a cross-sectional view taken along a line II-II 'in FIG. 2, and is a cross-sectional view showing a structure of a side other than a pad region of the liquid crystal panel and a region where LEDs are arranged. 4, the liquid crystal panel 110 is supported on the upper surface of the guide panel 125, and the light guide plate 120 is attached to the lower surface of the guide panel 120 by an adhesive means.

3 and 4, three outer surfaces of the liquid crystal panel 110 are supported by a guide panel 125, one surface (surface on the side where the LEDs are arranged) And is supported by the substrate 150. Also, the light guide plate 120 is attached to the lower surface of the guide panel 125 and the other side is attached to the LED substrate 150 attached to the guide panel 125, so that the light guide plate 120 is assembled.

A guide groove 172 having a predetermined width and depth is formed on a lower surface of the guide panel 125 along one side of the liquid crystal panel 110. The LED flexible circuit board 164 is disposed in the guide groove 172. One end of the LED flexible circuit board 164 is bonded to the LED substrate 150 and the other end is connected to an external driving circuit to apply a signal to the LED 152 from the outside.

The guide groove 172 extends from the area where the LED 152 is disposed along the guide panel 125 to the pad area of the liquid crystal panel 110 and is connected to an external LED control circuit to provide a signal to the LED 152 .

Hereinafter, the structure of the guide panel 125 in which the LED substrate 150 is assembled and the method of disposing the LED flexible circuit board 164 in the guide groove 172 will be described in detail.

5 is a partially enlarged perspective view of a guide panel 125 showing in detail a portion where the LED substrate 150 is assembled.

As shown in FIG. 5, the guide panel 125 is formed in a rectangular shape with a predetermined thickness and width to support the liquid crystal panel 110 and the optical sheet 130. The guide panel 125 includes a substrate seating portion 176 on which the LED substrate 150 is seated, a guide hole 175 formed at a predetermined length formed at one end of the substrate seating portion 176, And a guide groove 172 formed in a direction perpendicular to the substrate seating portion 176 on the back surface of the substrate seating portion 176.

6A to 6E are views showing assembling the LED substrate 150 on the guide panel 125 having the above structure.

First, as shown in FIG. 6A, the LED substrate 150 is attached to the substrate seating portion 176 of the guide panel 125. At this time, the attachment of the LED substrate 150 is performed by a bonding means such as a double-sided tape or an adhesive, and a surface attached to the substrate seating portion 176 is a surface on which the LED 152 is mounted. Therefore, the LED 152 mounted on the LED substrate 150 faces the back surface of the guide panel 125.

A light guide plate 120 is assembled on the upper surface of the LED substrate 150 and the surface on which the guide groove 172 is formed and the optical sheet 130 is placed thereon, 130, the liquid crystal panel 110 is positioned.

6B, the LED flexible printed circuit board 164 bonded to one end of the LED substrate 150 is passed through the guide hole 175 to the back surface of the guide panel 125, and then, as shown in FIG. 6C The LED flexible circuit board 164 is vertically folded and attached to the guide groove 172 formed on the back surface of the guide panel 125 as shown in FIG. At this time, a double-sided tape 177 is disposed in the guide groove 172 to firmly attach the LED flexible circuit board 164 to the fragile guide groove 172.

Since the LED flexible circuit board 164 is formed in a single shape and attached to one end of the LED substrate 150, the LED flexible circuit board 164 has a shape extending from the LED substrate 150. The LED flexible circuit board 164 extending to the back surface of the guide panel 125 through the guide hole 175 is inserted into the guide groove 125 through the guide groove 175, (Not shown).

6C, in order to attach the LED flexible circuit board 164 extending perpendicularly to the guide groove 172 to the guide groove 172, the LED flexible circuit board 164 is folded at 90 degrees to attach must do it. Thus, the faces before and after the fold are inverted with respect to each other.

6D, a double-sided tape 179 is attached along the edge of the guide panel 125, and then a reflection plate 140 is attached to the back surface of the guide panel 125 as shown in FIG. 6E . At this time, the reflection surface of the reflection plate 140 faces the front surface of the guide panel 125, so that the reflection surface faces the lower surface of the light guide plate 120.

As described above, in the present invention, not only the thickness of the liquid crystal display device is minimized by removing the lower cover, but also the LED flexible circuit board 164 attached to the LED substrate 150 and connected to an external circuit is guided to the guide panel 125 are accommodated in the guide grooves 172 formed on the back surface, the structure can be simplified. Therefore, not only the cost can be reduced, but also the assembly can be facilitated.

On the other hand, in the present invention described above, the structure of the guide panel or the like has a specific shape, but the present invention is not limited to this shape. Since the lower cover is removed and the LED flexible circuit board is provided in the guide groove on the rear side of the guide panel to manufacture a liquid crystal display device which is thin and light in weight and simplified in assembly, If the LED flexible printed circuit board can be housed in the groove, it can be applied to liquid crystal display devices having all the structures currently available.

101: liquid crystal display element 105: driving element
107: flexible circuit board 110: liquid crystal panel
120: light guide plate 125: guide panel
130: optical sheet 140: reflector
150: LED substrate 152: LED
164: LED flexible circuit board 172: guide groove
175: Guide hole

Claims (8)

A liquid crystal panel in which an image is implemented;
A light guide plate disposed under the liquid crystal panel and guiding light to supply the light to the liquid crystal panel;
An LED substrate disposed on one side of the light guide plate and having a plurality of LEDs for emitting light to the light guide plate;
A guide panel supporting the liquid crystal panel on the front surface and assembling the light guide plate and the LED substrate;
An LED flexible circuit board having one end connected to the LED substrate and the other end connected to the outside to transmit a signal to the LED; And
And a guide groove formed on a back surface of the guide panel and housing the LED flexible circuit board. The guide panel according to claim 1,
A substrate seating part formed on the front surface and on which the LED substrate is mounted; And
And an LED flexible circuit board connected to the LED substrate mounted on the substrate seating portion, the LED flexible circuit board being connected to the LED substrate. 3. The LED module according to claim 2, wherein the substrate seating portion on the front surface of the guide panel and the guide grooves on the rear surface are arranged perpendicular to each other, and the LED flexible printed circuit board inserted into the guide hole and penetrated to the rear surface of the guide panel, And is disposed in the guide groove after being folded. The liquid crystal display device according to claim 3, wherein the guide groove is provided with an adhesive means, and the LED flexible substrate is attached to the guide groove. The liquid crystal display device according to claim 1, wherein the light guide plate is attached to a bottom surface of the guide panel and a surface of the LED substrate on which the LED is mounted. The liquid crystal display device according to claim 1, wherein the reflective plate is attached to the rear surface of the guide panel after the LED flexible circuit board is housed in the guide groove. The liquid crystal display device according to claim 1,
A first substrate comprising a pad region and a pixel region;
A second substrate on which a color filter is formed; And
And a liquid crystal layer formed between the first substrate and the second substrate. The liquid crystal display device according to claim 7, wherein the LED substrate is disposed in a region opposite to the pad region.

Images