KR20070053849A - Liquid crystal display - Google Patents

Abstract

The present invention relates to a liquid crystal display device that can prevent light leakage by maximizing the adhesion between the light source unit, the mold frame, the light guide plate.

The present invention provides a liquid crystal display panel for displaying an image; A light source unit providing light to the liquid crystal display panel; A light guide plate including a light guide plate step portion formed stepwise between a light incident portion facing the light source unit and a corresponding portion corresponding to a display area of the liquid crystal display panel; And a mold frame including a mold step portion formed stepwise along the light guide plate step portion at a position corresponding to the light guide plate step portion.

Light guide plate, stepped part, mold frame, light leakage, LED

Description

Liquid Crystal Display {LIQUID CRYSTAL DISPLAY}

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

2 is a front view of the LED flexible substrate according to the embodiment of the present invention.

3 is a cross-sectional view taken along line III-III 'of FIG.

4 is a rear view of the LED flexible substrate according to the embodiment of the present invention.

5 is a plan view illustrating a light guide plate according to an exemplary embodiment of the present invention.

FIG. 6 is a cross-sectional view taken along line VI-VI ′ of FIG. 5.

7 is a rear view of a mold frame according to an embodiment of the present invention.

FIG. 8 is a perspective view of A of FIG. 7. FIG.

9 is a front view of a mold frame according to an embodiment of the present invention.

FIG. 10 is a perspective view of B shown in FIG. 9. FIG.

<Code Description of Main Parts of Drawing>

10 liquid crystal display device 30 liquid crystal display panel

60 drive circuit 70 flexible printed circuit board

100: backlight unit 110: light source unit

120: LED 160: LED flexible substrate

170: cover layer opening portion 190: light guide plate

210: reflective sheet 220: optical sheet

240: mold frame 280: mold step portion

The present invention relates to a liquid crystal display device, and more particularly to a liquid crystal display device that can prevent light leakage by maximizing the adhesion between the light source unit, the mold frame, the light guide plate.

As information technology advances, the market for computers and televisions as well as personal mobile communication devices such as mobile phones is increasing. The display device, which is the final connection medium between these devices and the user, is required to have high quality, and thus, a liquid crystal display device, which is not a conventional CRT (Cathode Ray Tube), has been in the spotlight recently.

A liquid crystal display device is a device that displays an image using liquid crystal. The liquid crystal display device includes a liquid crystal display panel for displaying an image, a backlight unit for providing light to the liquid crystal display panel, a mounting of the liquid crystal display panel and a mold frame for fixing the backlight unit.

The liquid crystal display panel includes a thin film transistor substrate and a color filter substrate bonded together with a liquid crystal interposed therebetween. The backlight unit includes a light source unit for providing light, a light guide plate for guiding light emitted from the light source unit, a reflection sheet positioned under the light guide plate to reflect light emitted from the lower part of the light guide plate in the direction of the light guide plate, and positioned above the light guide plate to form a liquid crystal display panel. It contains a number of optical sheets that evenly distribute and condense the light in the furnace. The mold frame mounts and fixes the backlight unit while mounting the liquid crystal display panel.

However, such a liquid crystal display does not properly adhere between the light source unit, the mold frame, and the light guide plate, so that a lot of light leakage defects occur in this area. These light leakage defects are particularly severe in high temperature and high humidity tests.

Accordingly, an object of the present invention is to provide a liquid crystal display device that can prevent light leakage by maximizing the adhesion between the light source unit, the mold frame, the light guide plate.

In order to achieve the above object, the present invention provides a liquid crystal display panel for displaying an image; A light source unit providing light to the liquid crystal display panel; A light guide plate including a light guide plate step portion formed stepwise between a light incident portion facing the light source unit and a corresponding portion corresponding to a display area of the liquid crystal display panel; And a mold frame including a mold step portion formed stepwise along the light guide plate step portion at a position corresponding to the light guide plate step portion.

The light source unit includes an LED for generating light; It characterized in that it comprises an LED flexible substrate for fixing the LED.

The mold frame, the LED flexible substrate, and the light guide plate may be adhered to the LED flexible substrate due to the adhesive member attached to the rear surface of the LED flexible substrate.

The LED flexible substrate may include a cover layer open portion thinly formed at a position corresponding to the light guide plate step portion and the mold step portion.

Specifically, the cover layer open portion is formed to cover the light guide plate step portion and the mold step portion.

On the other hand, the light guide plate is characterized in that the thickness of the light incident portion is thicker than the thickness of the corresponding portion.

Other objects and features of the present invention in addition to the above object will become apparent from the description of the embodiments with reference to the accompanying drawings. Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

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

Referring to FIG. 1, the liquid crystal display device 10 according to an exemplary embodiment of the present invention includes a liquid crystal display panel 30 for displaying an image, a driving circuit 60 for driving the liquid crystal display panel 30, and a driving circuit 60. A flexible printed circuit board 70 for driving the backlight unit 100, a backlight unit 100 for providing light to the liquid crystal display panel 30, a fixing of the backlight unit 100, and a mold frame 240 for mounting the liquid crystal display panel 30. ) Is included.

The liquid crystal display panel 30 includes a liquid crystal for controlling light transmittance, a thin film transistor substrate 40 and a color filter substrate 50 bonded together with a liquid crystal interposed therebetween.

The liquid crystal is rotated by the difference between the pixel voltage from the pixel electrode of the thin film transistor substrate 40 and the common voltage from the common electrode of the color filter substrate 50 to adjust the light transmittance. To this end, the liquid crystal is made of a material having dielectric anisotropy and refractive index anisotropy.

The thin film transistor substrate 40 includes a thin film transistor and a pixel electrode formed in a pixel region defined by the intersection of data lines and gate lines on a substrate such as glass.

The thin film transistor transfers the image signal supplied from the data line to the pixel electrode in response to the scan signal supplied from the gate line. The pixel electrode applies a pixel voltage to the liquid crystal using the image signal charged therein. To this end, the pixel electrode is formed of a transparent conductive metal such as indium tin oxide (ITO) or indium zinc oxide (IZO).

The color filter substrate 50 includes a black matrix formed in a matrix on a substrate such as glass, a red, green, blue color filter formed in a region partitioned by the black matrix, and a common electrode for applying a common voltage to the liquid crystal. .

The black matrix is formed of black metal or organic material that can block light in order to block external light and prevent light leakage current of the thin film transistor. The red, green, and blue color filters each contain red, green, and blue pigments that transmit or absorb light of a specific wavelength, and realize color through additive mixing of red, green, and blue light. The common electrode applies a common voltage to the liquid crystal. To this end, the common electrode is formed of a transparent conductive metal such as ITO or IZO.

The driving circuit 60 is mounted on a thin film transistor substrate 40 by a chip on glass (COG) method and includes a gate driving circuit supplying a scan signal to a gate line and data supplying an image signal to a data line. It consists of a driving circuit. Here, the gate driving circuit may be directly formed on the thin film transistor substrate 40.

The flexible printed circuit board 70 is connected to the thin film transistor substrate 40 through the anisotropic conductive film. In the flexible printed circuit board 70, a plurality of electronic devices 80 generating power signals, data signals, various control signals, etc. are mounted in a soldering manner to drive the driving circuit 60. Power signals, data signals and various control signals generated by the plurality of electronic devices 80 are supplied to the driving circuit 60 through the driving signal line 90.

The backlight unit 100 is a light source unit 110 for providing light, a light guide plate 190 for guiding the light emitted from the light source unit 110, and a light located under the light guide plate 190 and positioned under the light guide plate 190. The reflective sheet 210 reflecting light toward the light guide plate 190 and a plurality of optical sheets 220 positioned on the light guide plate 190 to uniformly disperse the light to the liquid crystal display panel 30 and simultaneously condense the light. have.

As illustrated in FIGS. 2 to 4, the light source unit 110 includes an LED 120 for emitting light and an LED flexible substrate 160 for fixing the LED 120.

The LED 120 includes a package body 150 having a cup-shaped cavity 130 accommodating the LED chip 140 therein and is attached to the LED flexible substrate 160 by soldering. However, such a thickness (C) of the LED 120 is difficult to form less than 0.6mm. For this reason, the cavity 130 is required to have a width greater than or equal to a predetermined dimension to guide the light generated from the LED chip 140 to the light guide plate 190, and the package body 150 also has a thickness greater than or equal to a predetermined dimension to secure a desired intensity. Because it is required.

The LED 120 is attached to the rear surface of the LED flexible substrate 160 by a soldering method. In order to apply driving power to the LED 120, a plurality of LED driving signal lines 162 are formed in the LED flexible substrate 160. One side of the plurality of LED driving signal lines 162 is connected to the anode pads 164 and the first and second cathode pads 166 and 168, respectively. Here, the LED driving signal lines 162 connected to the anode pads 164 of the plurality of LED driving signal lines 162 are connected to the anodes of all of the LEDs 120, and the first and the plurality of LED driving signal lines 162 are connected. Each of the LED driving signal lines 162 connected to the second cathode pads 166 and 168 is connected to the cathodes of the respective LEDs 120.

In addition, an adhesive member 180 is attached to the rear surface of the LED flexible substrate 160 to bond the LED flexible substrate 160 of the light source unit 110 to the mold frame 240 and the light guide plate 190. That is, the LED flexible substrate 160 of the light source unit 110 is seated on the light source unit seating portion of the mold frame 240 and then bonded to the mold frame 240 by the adhesive member 180 and the light guide plate 190. Are glued. However, since the LED flexible substrate 160 does not bend well due to its strength, adhesion between the mold frame 240 and the light guide plate 190 may not be performed properly, and thus light leakage may occur. In order to prevent this, the LED flexible substrate 160 is formed with a cover layer open portion that is formed relatively thinly at a position corresponding to the light guide plate step 192 and the mold step 280. The cover layer opening 170 is bent well because the thickness is relatively thin, as shown in FIG. That is, the cover layer open part 170 covers the light guide plate step part 192 and the mold step part 280 and is bonded to the cover layer opening part 170 through the adhesive member 180. Due to the cover layer opening 170, the LED flexible substrate 160 has maximum adhesiveness with the light guide plate step 192 and the mold step 280, and light leakage does not occur.

The light guide plate 190 is mounted on the rear surface of the mold frame 240 to guide the light emitted from the LED 120 to the liquid crystal display panel 30. In order to seat the light guide plate 190 on the rear surface of the mold frame 240, the light guide plate 200 protruding from the light guide plate 190 is formed at a predetermined position of the edge of the light guide plate 190. Meanwhile, as illustrated in FIG. 6, the thickness D of the light incident part 194 of the light guide plate 190 facing the LED 120 is the thickness of the LED 120, that is, 0.6 mm. However, in order to reduce the weight of the liquid crystal display device 10, the thickness E of the light guide plate 190 in the corresponding portion 198, which is an area corresponding to the display area, which is an area where the image of the liquid crystal display panel 30 is actually displayed. Is 0.5mm. Due to the thickness difference between the light incident part 194 and the corresponding part 198, the light guide plate 190 has the light guide plate step part 192.

The reflective sheet 210 is coated with a material having a high reflectance on a base material. That is, Ag, Ti, etc. are mainly coated as a reflective member on a base material such as SUS (Steel Use Stainless), brass, aluminum, and polyethylene terephthalate (PET). The reflective sheet 210 returns the light emitted under the light guide plate 190 back to the light guide plate 190.

The plurality of optical sheets 220 are generally composed of two or more sheets and are positioned on the light guide plate 190 to uniformly disperse and condense light to the liquid crystal display panel 30. The plurality of optical sheets 220 scatters the light emitted from the light guide plate 190 to spread the light evenly and diffuses the sheet, and the light from the diffusion sheet is refracted and condensed, thereby increasing the luminance, and scratches are easily generated. It is composed of two or more protective sheet to protect the prism sheet which can show phenomena, and to spread the light to widen the viewing angle narrowed by the prism sheet, and to improve the luminance. The optical sheet ear portion 230 is formed at a predetermined position of the edge of the plurality of optical sheets 220, and thus the plurality of optical sheets 220 may be seated on the mold frame 240.

The rear surface of the mold frame 240 seats and fixes the light guide plate 190. To this end, as shown in FIGS. 7 and 8, the light guide pinning part seating part 250 is formed at a position corresponding to the light guide pinning part on the rear surface of the mold frame 240. After the light guide pinning part is seated on the light guide pinning part seating part, it is fixed by sidewalls surrounding the light guide pinning part seating part 250. In addition, the rear surface of the mold frame 240 seats and fixes the reflective sheet. That is, the rear surface of the mold frame 240 seats the reflective sheet after the light guide plate is seated on the mold frame 240. To this end, a reflective sheet seating portion 252 is formed on the rear surface of the mold frame 240. The reflective sheet is fixed to the reflective sheet seating part 252 and then fixed by sidewalls surrounding the reflective sheet seating part 252.

The front of the mold frame 240 seats and fixes the plurality of optical sheets 220. To this end, as shown in Figure 9, the front of the mold frame 240, the optical sheet ear seating portion 260 is formed at a position corresponding to the optical sheet ear. The plurality of optical sheet ear portions are seated on the optical sheet ear portion 260 and then fixed by sidewalls surrounding the optical sheet ear portion 260. On the front of the mold frame 240, a plurality of optical sheets are mounted on the mold frame 240, and then a liquid crystal display panel is mounted. Then, the backlight unit 100 is fastened by fastening the top chassis 20 and the bottom chassis 290. ), The liquid crystal display panel 30 and the mold frame 240 are fixed.

In addition, the front of the mold frame 240 is seated and bonded to the light source unit (110). To this end, the light source unit seating portion 270 is formed on the front of the mold frame 240, as shown in FIG. However, as shown in FIG. 10, the mold stepped portion 280 is formed at a position corresponding to the light guide plate stepped portion and the cover layer open portion at a predetermined position of the edge of the light source unit seating portion 270. In other words, the mold step part 280 has a step corresponding to the light guide plate step part and the cover layer opening part having a step. For this reason, adhesion between the LED flexible substrate 160, the mold frame 240, and the light guide plate 190 is well performed, so that light leakage defects do not occur.

As described above, the liquid crystal display device of the present invention includes a cover layer open portion formed on the LED flexible substrate of the light source unit and a mold step portion formed on the mold frame in correspondence to the light guide plate portion. The cover layer open portion is relatively thinner than the thickness of other areas of the LED flexible substrate. As a result, the LED flexible board is bent at the cover layer opening. That is, the LED flexible substrate, the mold frame, and the light guide plate are well bonded by the adhesive member attached to the rear surface of the LED flexible substrate and can prevent light leakage defects caused by poor adhesion.

In the detailed description of the present invention described above with reference to the preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge of the present invention described in the claims to be described later It will be understood that various modifications and variations can be made in the present invention without departing from the spirit and scope of the art.

Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification but should be defined by the claims.

Claims (6)

A liquid crystal display panel for displaying an image; A light source unit providing light to the liquid crystal display panel; A light guide plate including a light guide plate step portion formed stepwise between a light incident portion facing the light source unit and a corresponding portion corresponding to a display area of the liquid crystal display panel; And a mold frame including a mold step portion formed stepped along the light guide plate step at a position corresponding to the light guide plate step. The method of claim 1, The light source unit LED for generating light; And an LED flexible substrate for fixing the LED. The method of claim 2, And the mold frame, the LED flexible substrate, and the light guide plate are adhered to the LED flexible substrate by an adhesive member attached to a rear surface of the LED flexible substrate. The method of claim 2, And the LED flexible substrate includes a cover layer open portion thinly formed at a position corresponding to the light guide plate step portion and the mold step portion. The method of claim 4, wherein And the cover layer open part is formed to cover the light guide plate step part and the mold step part. The method of claim 1, And the light guide plate is thicker than the corresponding light incident portion.

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