KR20090128693A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: An LCD equipped with a light shield tape is provided to prevent the leakage of the light and improve luminance and color uniformity by composing a shield tape in order to cope with the part in which the FPCB and light guide plate of the LED assembly. CONSTITUTION: A support main(130) comprises a protrusion step(131) in one inner side. A curtain tape(200) comprises a protrusion in the bottom surface along the longitudinal direction and is attached to the lower surface of the protrusion step. An LED(Light Emitting Diode) assembly is disposed on light shield tape and fixed to a protrusion step. The LED assembly is included with a plurality of LEDs of a FPCB(Flexible Printed Circuit Board) in which LEDs are mounted.

Description

Liquid crystal display device

The present invention relates to a liquid crystal display device, and more particularly to a light shielding tape that can block light leakage.

In line with the recent information age, the display field has also been rapidly developed, and a liquid crystal display device (FPD) is a flat panel display device (FPD) having advantages of thinning, light weight, and low power consumption. LCD, plasma display panel device (PDP), electroluminescence display device (ELD), field emission display device (FED), etc. : It is rapidly replacing CRT.

Among them, LCDs are excellent in moving image display and are most actively used in notebooks, monitors, TVs, etc. due to high contrast ratio. The LCDs are devices that do not have their own light emitting elements. It requires a light source.

As a result, a backlight unit having a lamp is provided on the rear side to irradiate light toward the front of the liquid crystal panel, thereby realizing an image of identifiable luminance.

On the other hand, a cold cathode fluorescent lamp (Cold Cathode Fluoresent Lamp), an external electrode fluorescent lamp (External Electrode Fluoresent Lamp), and a light emitting diode (LED) are used as the light source of the backlight unit.

Among them, LEDs are particularly widely used as display light sources having features such as small size, low power consumption, and high reliability.

1 is a cross-sectional view of a general liquid crystal display module using an LED as a light source.

As illustrated, a general liquid crystal display module includes a liquid crystal panel 10, a backlight unit 20, a support main 30, a cover bottom 50, and a top cover 40.

The liquid crystal panel 10 is a part that plays a key role in image expression and is composed of first and second substrates 12 and 14 bonded to each other with a liquid crystal layer interposed therebetween.

In addition, polarizers (not shown) are attached to upper and lower surfaces of the liquid crystal panel 10, and a backlight unit 20 is provided behind the liquid crystal panel 10.

In this case, the backlight unit 20 includes an LED assembly 29 arranged along at least one edge length direction of the support main 30, a white or silver reflecting plate 25 mounted on the cover bottom 50, and the like. The light guide plate 23 mounted on the reflective plate 25 and a plurality of optical sheets 21 interposed thereon are included.

The LED assembly 29 is configured on one side of the light guide plate 23, and includes a plurality of LEDs 29a emitting light and a flexible printed circuit board 29B on which the LEDs 29a are mounted.

The liquid crystal panel 10 and the backlight unit 20 have a top cover 40 surrounding the top edge of the liquid crystal panel 10 and a back surface of the backlight unit 20 in a state where the edges are surrounded by the support main 30 having a rectangular frame shape. Cover cover 50 to cover each is coupled in front and rear are integrated through the support main 30 as a medium.

As a part of the liquid crystal display module, the corresponding portion will be described in more detail with reference to FIG. 2, which is an enlarged cross-sectional view of region A of FIG. 1.

As shown, the LED 29a is arranged along one side of the light guide plate 23 of the general liquid crystal display module, and the LED 29a is mounted on the FPCB 29b.

At this time, only one LED 29a is shown in the drawing, but a plurality of LEDs 29a are mounted on the FPCB 29b at regular intervals, thereby lighting white light at a time.

The LED assembly 29 is fixed by a method such as adhesive so that the light (F) emitted from the plurality of LED (29a) to face the light guide plate 23, the light incident plate side of the light guide plate for this purpose is the LED assembly It is attached and fixed to the lower surface of the FPCB through the adhesive material 60, such as double-sided tape.

Accordingly, the light F emitted from the LED 29a is refracted toward the liquid crystal panel 10 after being incident on the light incident part of the light guide plate 23 and is reflected by the reflective sheet 25. While passing through the optical sheet 21, it is processed into a more uniform surface light source of high quality and is supplied to the liquid crystal panel 10.

On the other hand, such a liquid crystal display device has a large display area and has a significantly reduced weight and volume, and in recent years, attempts to provide a thin liquid crystal display device by reducing the volume of the backlight unit 20 have been made.

However, the liquid crystal display device exhibits some problems. Particularly, some of the light emitted from the LED 29a generates light leakage through the adhesive material 60 between the FPCB 29b and the light guide plate 23. The light emitted by the light leaks directly to the outside of the liquid crystal panel 10 and is visually seen as shown in FIG. 3.

As a result, the quality of the liquid crystal display, such as a decrease in luminance and color uniformity, is degraded.

The present invention has been made to solve the above problems, and the present invention is intended to prevent light leakage of the liquid crystal display device.

For this reason, the second object is to improve the luminance and color uniformity of the liquid crystal display device.

In order to achieve the object as described above, the present invention and the support main is configured with a protruding end on any one inner surface in a rectangular frame shape; A light blocking tape attached to the lower surface of the protruding end and including a protrusion on a bottom surface in a longitudinal direction thereof; An LED assembly comprising a plurality of LEDs and an FPCB (flexible printed circuit board) on which the plurality of LEDs are mounted, the reflecting plate being sequentially seated in the support main; A backlight unit further comprising a light guide plate seated on the reflective plate and an optical sheet seated on the light guide plate; A liquid crystal panel mounted on the backlight unit; A cover bottom configured to be in close contact with the support main back surface; And a top cover configured to rim an edge of the liquid crystal panel and to be assembled to the support main and the cover bottom, wherein the protrusion of the light-shielding tape is positioned between the FPCB and the plurality of optical sheets. do.

In this case, the light shielding tape has a bar shape and has a wider width than the FPCB, and the width of the light shielding tape is 1.0 to 1.5 times or more than the width of the FPCB.

The protrusion may correspond to the thickness of the FPCB.

As described above, according to the present invention by further configuring the shading tape to correspond to the portion where the FPCB and the light guide plate of the LED assembly are bonded to each other through the adhesive material, there is an effect that can prevent light leakage due to the site have.

As a result, there is an effect of improving the luminance and color uniformity of the liquid crystal display device.

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

4 is an exploded perspective view of a liquid crystal display module according to an exemplary embodiment of the present invention.

As illustrated, the liquid crystal display module includes a liquid crystal panel 110, a backlight unit 120, a support main 130, a cover bottom 150, and a top cover 140.

First, the liquid crystal panel 110 plays a key role in image expression and includes a first substrate 112 and a second substrate 114 bonded to each other with the liquid crystal layer interposed therebetween.

At this time, although not shown in the drawings under the premise of an active matrix method, a plurality of gate lines and data lines intersect each other and a pixel is defined on an inner surface of the first substrate 112, which is commonly referred to as a lower substrate or an array substrate. Thin film transistors (TFTs) are provided at the intersections of the transistors and are in one-to-one correspondence with transparent pixel electrodes formed in each pixel.

In addition, the inner surface of the second substrate 114 called the upper substrate or the color filter substrate may correspond to each pixel, for example, a color filter of red (R), green (G), and blue (B) color, and each of them. A black matrix covering the non-display elements such as gate lines, data lines, and thin film transistors is provided. In addition, a transparent common electrode covering them is provided.

A polarizer (not shown) for selectively transmitting only specific light is attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

In addition, the printed circuit board 117 is connected to at least one edge of the liquid crystal panel 110 through a connection member 116 such as a flexible circuit board or a tape carrier package (TCP) to support the modularization process. The side surface of the main 130 or the cover bottom 150 is properly folded to be in close contact.

Accordingly, in the liquid crystal panel 110 having the above-described structure, when the thin film transistor selected for each gate line is turned on by the on / off signal of the gate driver circuit which is scanned and transmitted, the signal voltage of the data driver circuit is applied to the corresponding pixel through the data line. The direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode.

In addition, the liquid crystal display module according to the present invention is provided with a backlight unit 120 for supplying light from the rear surface of the liquid crystal panel 110 so that the difference in transmittance is expressed to the outside.

The backlight unit 120 includes an LED assembly 129, a white or silver reflector 125, a light guide plate 123 seated on the reflector 125, and a plurality of optical sheets 121 interposed thereon. Include.

The LED assembly 129 described above is located at one side of the light guide plate 123 so as to face the light incident part of the light guide plate 123, and the LED assembly 129 includes a plurality of LEDs 200 and LEDs 129a thereof. It includes a FPCB (129b) that is mounted at a predetermined interval apart.

In this case, the plurality of LEDs 129a emits light having red (R), green (G), and blue (B) colors toward the light-receiving portion of the light guide plate 123, respectively, and the plurality of RGB LEDs (129a). ) Can be lit at once to realize white light by color mixing.

At this time, by using the LED 129a configured with an LED chip (not shown) that emits all the colors of RGB, the white light may be implemented in each LED 129a, or a chip that emits complete white including a chip emitting white. LED 129a may be used.

Meanwhile, a plurality of LEDs 129a emitting RGB light may be bundled and mounted in a cluster, and a plurality of LEDs 129a mounted on the FPCB 129b may be arranged on the FPCB 129b. It is also possible to arrange them side by side or to arrange them side by side in a plurality of columns.

The light guide plate 123 evenly spreads the light incident from the plurality of LEDs 129a to a wide area of the light guide plate 123 while propagating through the light guide plate 123 by a plurality of total reflections to provide a surface light source to the liquid crystal panel 110. do.

The light guide plate 123 may include a pattern of a specific shape on the rear surface to supply a uniform surface light source.

The reflective plate 125 is positioned on the rear surface of the light guide plate 123, and reflects light passing through the rear surface of the light guide plate 123 toward the liquid crystal panel 110 to improve the brightness of the light.

The plurality of optical sheets 121 on the light guide plate 123 include a diffusion sheet and at least one light collecting sheet, and diffuse or condense the light passing through the light guide plate 123 to provide a more uniform surface to the liquid crystal panel 110. Allow the light source to enter.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the top cover 140, the support main 130, and the cover bottom 150. The top cover 140 is the top and side surfaces of the liquid crystal panel 110. A rectangular frame having a cross section bent in a shape of “a” so as to cover an edge thereof is configured to open an entire surface of the top cover 140 to display an image implemented in the liquid crystal panel 110.

In addition, the cover bottom 150 on which the liquid crystal panel 110 and the backlight unit 120 are seated, and which is the basis for assembling the entire structure of the liquid crystal display device module, has a rectangular plate shape and vertically bends its four edges to a predetermined height. Configure.

In addition, the support main 130 having a rectangular frame shape seated on the cover bottom 150 and covering the edges of the liquid crystal panel 110 and the backlight unit 120 may include the top cover 140 and the cover bottom 150. Combined.

Here, a protruding end 131 of a predetermined shape is formed on the inner surface of the support main 130 so that the light shielding tape 200 is attached to the lower surface thereof and simultaneously supports a part of the rear surface of the liquid crystal panel 110.

In this case, the top cover 140 may also be referred to as a case top or a top case, and the support main 130 may also be referred to as a guide panel, a main support, or a mold frame, and the cover bottom 150 may be referred to as a bottom cover or a lower cover. It is also built.

On the other hand, the light shielding tape 200 that shields light from leaking to a portion outside the screen display area of the liquid crystal panel 110 is formed through an adhesive material portion between the FPCB 129b and the light guide plate 123 of the LED assembly 129. Light leakage is blocked, which will be described in more detail with reference to FIGS. 5A through 5B.

FIG. 5A is a perspective view schematically showing the structure of the light shielding tape of the present invention, and FIG. 5B is a bottom perspective view showing the bottom of FIG. 5A.

As shown, the shading tape 200 is composed of a base film 203 made of PET resin and an adhesive material layer 205, which is black in overall for efficient light shading.

The overall shape of the light blocking tape 200 has a bar shape and has a length corresponding to the FPCB (129b of FIG. 4) of the LED assembly (129 of FIG. 4).

The light shielding tape 200 is attached to the lower surface of the protruding end (131 of FIG. 4) of the support main (130 of FIG. 4) through the adhesive material layer 205, and the light shielding tape 200 is FPCB (FIG. 4). 129b) has a constant width w1.

The width w1 of the LED assembly (129 of FIG. 4) may cover a portion of an edge of the plurality of optical sheets (121 of FIG. 4) seated on the FPCB (129b of FIG. 4) and the light guide plate (123 of FIG. 4). It is preferable to configure to have.

In particular, the light shielding tape 200 of the present invention is characterized in that the protrusion 201 protruding along the longitudinal direction of the light shielding tape 200 on the opposite surface of the adhesive material layer 205 is further configured.

The protrusion 201 is located between the FPCB (129b of FIG. 4) of the LED assembly (129 of FIG. 4) and the plurality of optical sheets (121 of FIG. 4), so that a portion of the light emitted from the LED (129a of FIG. 4) is present. The light is prevented from leaking through the adhesive material between the FPCB (129b of FIG. 4) and the light guide plate (123 of FIG. 4).

Through such a light shielding tape 200, light leakage occurring to an adhesive material portion between the FPCB (129b of FIG. 4) and the light guide plate (123 of FIG. 4) may be prevented.

FIG. 6 is a schematic cross-sectional view of some cross-section of FIG. 4 modularized.

As illustrated, the reflective plate 125, the light guide plate 123, the LED assembly 129 provided on one side of the light guide plate 123, and a plurality of optical sheets 121 are stacked on the light guide plate 123. It forms a backlight unit.

The LED assembly 129 is fixed in position by bonding or the like so that the light emitted from the plurality of LEDs 129a faces the light-receiving part of the light guide plate 123. For this, the light-receiving part side of the light guide plate 123 is an LED assembly. The FPCB 129b of 129 is attached and fixed through an adhesive material 160 such as a double-sided tape.

In addition, the liquid crystal panel 110 having a liquid crystal layer (not shown) interposed therebetween is disposed between the backlight unit and the first and second substrates 112 and 114, and the first and second substrates 112 and 114. On each of the outer surfaces of), a polarizing plate (not shown) for selectively transmitting only specific light is attached.

The backlight unit and the liquid crystal panel 110 are surrounded by edges by the support main 130, and the cover bottom 150 is coupled to the rear surface of the backlight unit and the liquid crystal panel 110, and the top cover 140 covering the upper edge and side surfaces of the liquid crystal panel 110. Is coupled to the support main 130 and cover bottom 150.

At this time, the inner side of the support main 130 is formed with a protruding end 131 protruding from a certain shape, and the upper end of the protruding end 131 supports the liquid crystal panel 110 and a light shielding tape on the lower side thereof. 200 is attached.

That is, the light shielding tape 200 is positioned between the protruding end 131 of the support main 130 and the LED assembly 129.

At this time, the width w1 of the shading tape 200 is configured to be wider than the width w2 of the FPCB 129b of the LED assembly 129, so that the shading tape 200 has the FPCB 129b of the LED assembly 129. Make sure that it is completely covered.

Therefore, the width w1 of the light shielding tape 200 is preferably 1.5 times or more the width w2 of the FPCB 129b of the LED assembly 129.

In particular, the protrusion 201 formed on the bottom surface of the light shielding tape 200 of the present invention is positioned between the FPCB 129b of the LED assembly 129 and the plurality of optical sheets 121.

The protrusion 201 may have a thickness d corresponding to the thickness of the plurality of optical sheets 121 or the FPCB 129b.

Therefore, the light emitted from the LED 129a and incident into the light guide plate 123 evenly spreads into the light guide plate 123 while traveling in the light guide plate 123 by a plurality of total reflections.

In this case, some of the light emitted from the LED 129a is directly emitted through the portion of the adhesive material 160 between the FPCB 129b and the light guide plate 123 to the liquid crystal panel 110 to generate light leakage. Alternatively, as shown in FIG. 7, it is confirmed that the light leakage is significantly reduced by the light shielding tape 200.

On the other hand, the liquid crystal display device has recently been widely used, such as a desktop computer monitor and a wall-mounted television, as well as a portable computer, and researches to have a significantly reduced weight and volume while having a large display area are actively conducted. It is becoming a trend.

For example, the thickness of the light guide plate 123 may be reduced to reduce the thickness of the backlight unit (120 of FIG. 4) and the liquid crystal display.

8 is a view schematically showing a state in which the thickness of the light guide plate 223 is reduced. The light guide plate 223 includes an inclined surface that is rapidly reduced, and a portion of the light guide plate 223 excluding the light incident part has a constant thickness. (h2) or characterized by having a gentle slope.

That is, for example, the light guide plate 223 is configured such that the parallel lower surface and the upper surface corresponding to the lower surface are inclined at the light incidence part, and as the distance from the light incidence part increases, the thickness h2 is smaller than the thickness h1 of the light incidence part. ) To be thinner.

In this case, the plurality of optical sheets 221 are interposed on the upper surface of the light guide plate 223 other than the inclined light incident portion, so that the overall thickness of the backlight unit including the light guide plate 223 and the plurality of optical sheets 221 is the light guide plate 223. ), The light incident part thickness h1 is not exceeded.

This reduces the thickness of the backlight unit and the thickness of the liquid crystal display device.

FIG. 9A is a partial cross-sectional view of a liquid crystal display module according to a second embodiment of the present invention, and FIG. 9B is an enlarged view of region B of FIG. 9A.

In this case, in order to avoid redundant description, the same reference numerals are given to the same parts that play the same role as the description of FIGS. 6 and 8, and only the characteristic contents to be described above will be described.

As illustrated, the liquid crystal display module includes a liquid crystal panel 210 including first and second substrates 212 and 214 bonded to each other with a liquid crystal layer interposed therebetween, and the liquid crystal panel 210 of the liquid crystal panel 210. The backlight unit 220 is provided to supply light from the rear surface, and the top cover 240 and the backlight unit 220 covering the upper edge of the liquid crystal panel 210 with the edges of the support main 230 having a rectangular frame. Cover cover 250 that covers the back of the) is respectively coupled to the front and rear is integrated through the support main 230.

Here, the backlight unit 220 includes an LED assembly 229 arranged along one longitudinal direction of the support main 230, a reflector 225 mounted on the cover bottom 250, and the reflector 225. It includes a light guide plate 223 seated on and a plurality of optical sheets 221 interposed thereon.

At this time, the LED assembly 229 is a FPCB (229b) in which a plurality of LEDs 229a emitting red (R), green (G), blue (B) colored light and a plurality of LEDs 229a are mounted at a predetermined interval. It is composed of

The LED assembly 229 is bonded and fixed to the lower surface of the protruding end 231 protruding to the inner surface of the support main 230 with the light blocking tape 200 interposed therebetween.

On the other hand, the light guide plate 223 includes an inclined surface that is sharply reduced, the other portion of the light guide plate 223 except for the light incident portion is characterized in that it is formed with a constant thickness or has a gentle slope.

The light guide plate 223 is attached and fixed to the lower surface of the FPCB 229b through the adhesive material 260 so that the light incident part faces the LED 229a of the LED assembly 229.

In this case, a part of the FPCB 229b to which the light guide plate 223 is attached is bent along the inclined surface of the light guide plate 223, and is disposed between the LED assembly 229 and the protruding end 231 of the support main 230. Attached shading tape 200 is also bent along the inclined surface of the light guide plate 223 is configured.

The light blocking tape 200 includes a protrusion 201 protruding on a bottom surface of the light blocking tape 200 along a length direction of the light blocking tape 200, and the protrusion 201 of the light blocking tape 200 is connected to the FPCB 229b of the LED assembly 229. It is positioned between the plurality of optical sheets 221.

As a result, some of the light emitted from the LED 229a is directly emitted to the liquid crystal panel 210 through the portion of the adhesive material 260 between the FPCB 229b and the light guide plate 223 so that light leakage occurs. Unlike the light blocking tape 200, the light leakage does not occur.

As described above, the present invention further configures the light shielding tape 200 to correspond to a portion where the FPCB 229b and the light guide plate 223 of the LED assembly 229 are bonded to each other through the adhesive material 260. It is possible to prevent light leakage caused by the site.

As a result, there is an effect of improving the luminance and color uniformity of the liquid crystal display device.

The present invention is not limited to the above embodiments, and various modifications can be made without departing from the spirit of the present invention.

1 is a cross-sectional view of a general liquid crystal display module using an LED as a light source.

FIG. 2 is an enlarged cross-sectional view of region A of FIG. 1. FIG.

Figure 3 is a photograph showing a light leakage phenomenon occurring in the prior art.

4 is an exploded perspective view of a liquid crystal display module according to an embodiment of the present invention.

Figure 5a is a perspective view schematically showing the structure of a light shielding tape of the present invention.

FIG. 5B is a bottom perspective view of the bottom of FIG. 5A; FIG.

FIG. 6 is a schematic cross-sectional view of a partial cross section of FIG. 4 modularized

Figure 7 is a photograph showing the appearance of no light leakage phenomenon in accordance with an embodiment of the present invention.

8 is a schematic cross-sectional view of a light guide plate according to a second exemplary embodiment of the present invention.

9A is a partial cross-sectional view of a liquid crystal display module according to a second embodiment of the present invention.

FIG. 9B is an enlarged view of region B of FIG. 9A;

Claims (4)

A support main having a protruding end formed on one of the inner surfaces of the rectangular frame; A light blocking tape attached to the lower surface of the protruding end and including a protrusion on a bottom surface in a longitudinal direction thereof; An LED assembly comprising a plurality of LEDs and an FPCB (flexible printed circuit board) on which the plurality of LEDs are mounted, the reflecting plate being sequentially seated in the support main; A backlight unit further comprising a light guide plate seated on the reflective plate and an optical sheet seated on the light guide plate; A liquid crystal panel mounted on the backlight unit; A cover bottom configured to be in close contact with the support main back surface; The top cover is assembled to the edge of the liquid crystal panel and assembled to the support main and cover bottom And the protrusion of the light blocking tape is positioned between the FPCB and the plurality of optical sheets. The method of claim 1, The light blocking tape has a bar shape and has a width wider than that of the FPCB. The method of claim 2, And the width of the light blocking tape is 1.0 to 1.5 times or more than the width of the FPCB. The method of claim 1, And the protrusion corresponds to a thickness of the FPCB.

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