KR102057889B1 - Liquid crystal display device having light emitting device back light unit - Google Patents

Abstract

The present invention relates to a liquid crystal display device that is lightweight, thin, and easy to assemble, and includes an LCD panel in which an image is implemented; A light guide plate disposed under the liquid crystal panel to guide light to the liquid crystal panel; An LED substrate disposed on one side of the light guide plate and mounted with a plurality of LEDs emitting light with the light guide plate; A guide panel supporting the liquid crystal panel on the front surface and assembling a light guide plate and an 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 rear surface of the guide panel to accommodate the LED flexible circuit board.

Description

Liquid crystal display device with LED backlight {LIQUID CRYSTAL DISPLAY DEVICE HAVING LIGHT EMITTING DEVICE BACK LIGHT UNIT}

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 that can minimize the thickness and reduce the manufacturing cost.

Nowadays, flat panel display devices for light and thin components such as liquid crystal display (LCD) are used not only for various portable electronic devices such as mobile phones, tablet computers and notebook computers but also for large electronic devices such as TVs. Is being applied.

Such a liquid crystal display element is a transmissive display element, and a desired image is displayed on the screen by adjusting the amount of light passing through the liquid crystal layer by the refractive index anisotropy of the liquid crystal molecules. Accordingly, in the liquid crystal display device, a back light, which is a light source passing through the liquid crystal layer, is provided for displaying an image. In general, the backlight can be classified into two types.

First, the light source is provided on the side of the liquid crystal panel to provide light to the liquid crystal layer, and second, the direct light source to provide light directly from the bottom of the liquid crystal panel.

In the side type backlight, a light source may be installed on the side of the liquid crystal panel to supply light to the liquid crystal layer through the reflector and the light guide plate. Therefore, since the thickness can be made thin, it is mainly used in notebooks and the like which require a thin display device. However, in the side type backlight, since a light source emitting light is located on the side of the liquid crystal panel, it is not only difficult to apply to a large area liquid crystal panel but also light is supplied through the light guide plate, thereby making it difficult to obtain high luminance. Therefore, there has been a problem that it is not suitable for the large-area liquid crystal panel for LCD TVs, which is in the spotlight recently.

The direct type backlight is not only applied to a large area liquid crystal panel because light emitted from a light source is directly supplied to the liquid crystal layer, and thus high brightness is possible.

On the other hand, in recent years, as a light source of the backlight, instead of a fluorescent lamp, a light source that emits light itself, such as a light emitting device (Light Emitting Device). Since the light emitting device emits R, G, and B monochromatic light, it has the advantage of good color reproduction and reduction of driving power when applied to the backlight.

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

 As shown in FIG. 1, the liquid crystal display device includes a first substrate 1 and a second substrate 3 and a liquid crystal layer (not shown) therebetween to implement an image as a signal is applied from the outside. An LED 52 including a liquid crystal panel 10, a light emitting device (LED) disposed on a lower side of the liquid crystal panel 10 to emit light, and an LED substrate on which the plurality of LEDs 52 are mounted ( 50, a light guide plate 20 disposed below the liquid crystal panel 10 to guide the light emitted from the LED 52 to the liquid crystal panel 10, and the liquid crystal panel 10 and the light guide plate ( A diffusion sheet 32 provided between the plurality of light guide plates 20 to diffuse the light supplied from the light guide plate 20 to the liquid crystal panel 10, and a prism sheet positioned on the diffusion sheet 32 to collect the diffused light. 34, a reflector 27 disposed below the light guide plate 20 and reflecting light input downward to the liquid crystal panel 10; A guide panel 25 supporting the light guide plate 20, the liquid crystal panel 10, a lower portion of the guide panel 25, the liquid crystal panel 10, the light guide plate 20, the diffusion sheet 32, The lower cover 40 to which the prism sheet 34 and the guide panel 25 are assembled, and the lower cover 40 are combined with the liquid crystal panel 10, the light guide plate 20, the diffusion sheet 32, and the prism sheet ( 34) and an upper cover 42 for supporting the guide panel 25.

Although not shown in the drawing, the first substrate 1 of the liquid crystal panel 10 includes a plurality of pixels, each pixel includes a pixel electrode and a thin film transistor, and the second substrate 3 includes a common electrode. When the signal is applied from the outside through the thin film transistor, an electric field is formed in the liquid crystal layer to control the orientation of the liquid crystal molecules, thereby controlling 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 each of the first substrate 1 and the second substrate 3 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 occur in the liquid crystal display as described above. As shown in the figure, the conventional liquid crystal display device is supported by the liquid crystal panel 10, the light guide plate 20, the optical sheet, etc. by the guide panel 25, the guide panel 25 is the lower cover 40 And it is assembled by being combined with the upper cover 42. However, unlike the liquid crystal panel 10, the light guide plate 20, the optical sheet, and the like, the guide panel 25, the lower cover 40, and the upper cover 42 are not essential components for driving the liquid crystal display device, but essential components are provided. This is the configuration required for assembly. In addition, 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 reducing the thickness and weight of the liquid crystal display device.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a liquid crystal display device that is lightweight, thin, and easy to assemble.

In order to achieve the above object, the liquid crystal display device according to the present invention comprises a liquid crystal panel is implemented image; A light guide plate disposed under the liquid crystal panel to guide light to the liquid crystal panel; An LED substrate disposed on one side of the light guide plate and mounted with a plurality of LEDs emitting light with the light guide plate; A guide panel supporting the liquid crystal panel on the front surface and assembling a light guide plate and an 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 rear surface of the guide panel to accommodate the LED flexible circuit board.

The guide panel is formed on the front surface of the substrate mounting portion on which the LED substrate is seated; And

The LED board mounted on the board seating part and the LED flexible circuit board once connected to the rear side are made of guide holes, and the board seating part on the front side of the guide panel and the guide grooves on the back are vertically arranged to each other. The LED flexible printed circuit board inserted and penetrated to the rear of the guide panel is folded into the guide groove once vertically folded from the rear surface.

In the present invention, by removing the lower cover of the liquid crystal display and attaching the light guide plate directly to the lower portion of the guide panel, the thickness of the liquid crystal display can be minimized and the weight can be reduced. In addition, in the present invention, by assembling the LED flexible circuit board for supplying a signal to the LED in the guide groove formed on the back of the guide panel, the assembly of the liquid crystal display device can be simplified.

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

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

2 is a plan view briefly showing the structure of a liquid crystal display device according to the present invention. As shown in FIG. 2, the liquid crystal display device 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, and a liquid crystal. It is composed of an LED substrate 150 installed on the other side of the panel and mounted with a plurality of LEDs, and an LED flexible circuit board 164 connected to the LED substrate 150 to apply a signal to the LED.

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

Various wirings are formed on the LED substrate 150 and are electrically connected to a plurality of LEDs mounted thereon. In addition, one end of the LED flexible printed circuit board 164 is bonded to the LED substrate 150 and then extended to a pad area to be attached to the pad area. Wiring is formed on the LED flexible circuit board 164 and the wiring of the LED flexible circuit board 164 is electrically connected to the wiring of the LED substrate 150 when the LED flexible circuit board 164 is attached to the LED substrate 150. An external LED signal is connected to the LED through the LED flexible circuit board 164 and the LED substrate 150 to emit light.

In the conventional liquid crystal display device illustrated in FIG. 1, LEDs are disposed on both sides of the liquid crystal panel so that light is supplied from both sides to the liquid crystal panel, whereas in the present invention, LEDs are formed in opposite regions of the pad area to supply light to the liquid crystal panel. In this case, the signal is supplied to the LED by the LED flexible circuit board 164 extending from the pad region to the LED substrate 150.

The liquid crystal display device having the above configuration will be described in more detail with reference to FIGS. 3 and 4.

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

The backlight is disposed on the lower side of the liquid crystal panel 110 to mount a plurality of LEDs 152 to emit light, and the LED substrate 150 mounted on the lower portion of the liquid crystal panel 110 and the LED 152 The light guide plate 120 guides the emitted light to the liquid crystal panel 110, and is provided between the liquid crystal panel 110 and the light guide plate 120 to be guided by the light guide plate 120 and supplied to the liquid crystal panel 110. The optical sheet 130 includes a diffusion sheet and a prism sheet for diffusing and condensing light, and a reflecting plate 140 disposed under the light guide plate 120 to reflect light directed to the bottom of the light guide plate 120.

The optical sheet 130 is supported by the guide panel 125, the LED substrate 150 is attached to the guide panel 125, and the reflecting plate 140 is attached to the light guide plate 120. An upper cover 149 is disposed at an upper edge region of the liquid crystal panel 110, and the upper cover 149 is combined with the guide panel 125, whereby the liquid crystal panel 110 and the backlight are assembled to complete the liquid crystal display device. do.

Although not shown in the drawing, a plurality of gate lines and data lines are formed on the first substrate 101 vertically and horizontally to define a plurality of pixel regions, and thin film transistors, which are switching elements, are formed in each pixel region. The formed pixel electrode is formed on the pixel region. The thin film transistor may include a gate electrode connected to a gate line, a semiconductor layer formed by stacking amorphous silicon, etc. on the gate electrode, 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 figure, a driving device 105 such as a gate drive IC or a data drive IC may be mounted on the first substrate 101 of the pad region. 107 is attached to the pad area of the first substrate 101.

Although not shown in the drawing, a metal wiring is formed in the pad region of the first substrate 101 to be electrically connected to the driving device 105. In addition, a metal wiring is formed on the flexible circuit board 107 so that when the flexible circuit board 107 is attached to the pad region of the first substrate 101, the first substrate 101 and the flexible circuit board 107 are formed. The metal wiring is electrically connected, and an external signal is applied to the driving device 105 through the metal wiring of the flexible circuit board 107 and the metal wiring of the first substrate 101.

In addition, the driving device 105 outputs a scan signal or an image signal according to an input signal and supplies the scan signal or the image signal to the pixel area through a gate line or a data line.

The second substrate 102 is a color filter composed of a plurality of sub-color filters for implementing red (R), green (G), and blue (B) colors, and the sub-color filter. It is composed of a black matrix that separates and blocks light that passes through the liquid crystal layer.

The first substrate 101 and the second substrate 102 configured as described above are joined to face each other by a sealant (not shown) formed on the outer side of the image display area to form a liquid crystal panel. The first substrate 101 ) And the second substrate 102 are bonded through a bonding key (not shown) formed on the first substrate 101 or the second substrate 102.

In addition, although not shown in the drawing, the first and second substrates 102 and 102 are attached to the first polarizing plate and the second polarizing plate, respectively, to polarize the light input and output to the liquid crystal panel 110 to display an image. Implement

The light guide plate 120 is used to guide light input from the LED 152 to the liquid crystal panel 110, and the light incident on one side of the light guide plate 120 is reflected from the top and bottom surfaces of the light guide plate 120 to the other side. After being propagated, the light guide plate 120 is output to the outside. In this case, the light guide plate 120 may be formed of a rectangular parallelepiped, and a pattern or a groove may be formed on the bottom surface of the light guide plate 120 to scatter incident light.

The reflective plate 140 is disposed below the light guide plate 120 and extends to the lower portion of the guide panel 125 so that the reflective plate 140 is adhered to and fixed to the lower surface of the guide panel 125 by a double-sided tape 142. . In this case, an adhesive may be applied instead of the double-sided tape 142 as an adhesive means for bonding the reflective plate 140 to the lower surface of the guide panel 125. In addition, although not shown in the drawing, the reflective plate 140 may be attached to and 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 to improve 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 the light diffused by the diffusion sheet so that uniform light is supplied to the liquid crystal panel 110. Is made of. At this time, the prism of the two prism sheets are formed so as to cross vertically in the x, y-direction, respectively, so that the light is refracted in the x, y-direction to improve the straightness of the light.

A plurality of LEDs 152 are disposed along one side of the liquid crystal panel 110. In the present invention, the LED 152 is disposed opposite the pad area to which the flexible circuit board 107 is attached. At this time, the plurality of LEDs 152 is mounted on the LED substrate 150, the LED substrate 150 is a surface on which the LED 152 is mounted is attached to the upper surface of the upper surface of the guide panel 125. Therefore, in the present invention, the LED 152 is not arranged in the upper direction to be disposed toward the liquid crystal panel 110, but is arranged in the lower direction and toward the reflecting plate 140, so that the guide panel 125 and the light guide plate 120 are disposed. Is disposed between the sides. At this time, the LED substrate 150 is attached by the guide panel 125 and the adhesive means such as adhesive tape or adhesive.

The LED 152 may be an R, G, B LED that emits monochromatic light of R (Red), G (Green), B (Blue), or an LED device that emits white light.

When the LED emitting monochromatic light is disposed, the monochromatic light LEDs of R, G, and B are alternately arranged at regular intervals, and the monochromatic light emitted from the LED is mixed with white light and then supplied to the liquid crystal panel 110, and the white light is emitted. When the LED device is provided, the plurality of LED devices are arranged at a predetermined interval to supply white light to the liquid crystal panel 110.

In this case, the white light LED device is composed of a blue LED emitting blue light and a phosphor absorbing blue monochromatic light to emit yellow light. It is supplied to the panel 110.

In FIG. 3, reference numeral 156 denotes a pad for preventing a step, and is to prevent a defect due to a step during assembly by removing the step between the upper surface of the liquid crystal panel 110 and the LED substrate 150. In this case, the pad 156 is adhered to the LED substrate 150 by an adhesive means 157 such as a double-sided tape or an adhesive layer.

FIG. 4 is a cross-sectional view taken along the line II-II ′ of FIG. 2, and is a cross-sectional view showing a structure of a side other than the pad region and the LED region of the liquid crystal panel. As shown in FIG. 4, the liquid crystal panel 110 is placed and 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.

As shown in FIGS. 3 and 4, the outer three surfaces of the liquid crystal panel 110 are supported by the guide panel 125 and one surface (side of the side where the LED is disposed) is attached to the guide panel 125. Supported by the substrate 150. In addition, the light guide plate 120 also has three outer surfaces attached to the bottom surface of the guide panel 125 and one surface is attached to the LED substrate 150 attached to the guide panel 125 to assemble the light guide plate 120.

A guide groove 172 having a predetermined width and depth is formed on one surface of the liquid crystal panel 110 on the bottom surface of the guide panel 125. An 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 region where the LED 152 is disposed along the guide panel 125 to the pad region of the liquid crystal panel 110, and is connected to an external LED control circuit to provide a signal to the LED 152. Is authorized.

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

5 is an enlarged perspective view of a part of the 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 border 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 part 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 part 176, and the substrate seating part 176. The guide groove 172 is formed in the vertical direction of the substrate seating portion 176 on the back surface.

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

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

In addition, although not shown in the drawings, the light guide plate 120 is assembled on the upper surface of the upper surface of the LED substrate 150 and the guide groove 172 is formed thereon, the optical sheet 130 is located on the optical sheet ( The liquid crystal panel 110 is positioned on the 130.

Subsequently, as illustrated in FIG. 6B, the LED flexible printed circuit board 164, which is bonded to one end of the LED substrate 150, penetrates through the guide hole 175 to the back of the guide panel 125, and then in FIG. 6C. As illustrated, the LED flexible printed circuit board 164 is folded vertically and attached to the guide groove 172 formed on the rear surface of the guide panel 125. In this case, a double-sided tape 177 is disposed in the guide groove 172 to firmly attach the LED flexible circuit board 164 to the buying 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. However, since the guide groove 172 extends in the vertical direction with the substrate seating portion 176, the LED flexible circuit board 164 extending to the back of the guide panel 125 through the guide hole 175 is the guide groove. 172 is disposed perpendicularly.

Accordingly, in order to attach the LED flexible printed circuit board 164 extending perpendicular to the guide groove 172 to the guide groove 172, as shown in FIG. 6C, the LED flexible printed circuit board 164 is folded by 90 degrees. must do it. Thus, the faces before and after the fold are inverted.

Subsequently, as shown in FIG. 6D, the double-sided tape 179 is attached along the edge of the guide panel 125, and then the reflective plate 140 is attached to the rear surface of the guide panel 125 as shown in FIG. 6E. Attach. In this case, since the reflective surface of the reflective plate 140 faces the front surface of the guide panel 125, the reflective surface faces the lower surface of the light guide plate 120.

As described above, in the present invention, the thickness of the liquid crystal display is minimized by removing the lower cover, and the LED flexible circuit board 164 is attached to the LED substrate 150 and connected to an external circuit. 125) The structure can be simplified by accommodating the guide groove 172 formed on the rear surface. 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 such a shape. In the present invention, the lower cover is removed, and the LED groove is provided in the guide groove on the rear side of the guide panel to manufacture a liquid crystal display device that is thin and lightweight and simplified in assembly. If only the LED flexible circuit board can be accommodated in the groove, it will be applicable to the liquid crystal display device of all possible structures.

101: liquid crystal display device 105: driving device
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 to guide light to the liquid crystal panel;
An LED substrate disposed on one side of the light guide plate and mounted with a plurality of LEDs for emitting light with the light guide plate;
A guide panel supporting the liquid crystal panel on the front surface and assembling a light guide plate and an 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
It is formed on the back of the guide panel is composed of a guide groove for receiving the LED flexible circuit board,
Guide panel,
A substrate seating part formed on the front surface to which the LED substrate is seated; And
And a guide hole through which the LED flexible circuit board once connected to the LED seated on the substrate seating part penetrates to the rear surface. delete The LED flexible circuit board of claim 1, wherein the substrate seating portion of the front surface of the guide panel and the guide grooves on the rear surface of the guide panel are vertically aligned with each other. A liquid crystal display device, characterized in that it is disposed in the guide groove after being folded. 4. The liquid crystal display device according to claim 3, wherein the guide groove is provided with an adhesive means so that the LED flexible circuit board is attached to the guide groove. The liquid crystal display of claim 1, wherein the light guide plate is attached to a lower surface of the guide panel and a surface on which the LED of the LED substrate is mounted. The liquid crystal display device of claim 1, wherein the reflective plate is attached to the rear surface of the guide panel after the LED flexible circuit board is accommodated in the guide groove. The liquid crystal panel of claim 1, wherein
A first substrate comprising a pad area and a pixel area;
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 of claim 7, wherein the LED substrate is disposed in an area opposite to the pad area.

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