KR20110014305A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display embodying a surface light source of the uniform luminance by covering a light leakage defect area by diffusing patterns is provided to remove the light leakage defect of the both sides of the light guide plate. CONSTITUTION: A first and a second lamps are arranged according to both sides of a light guide plate(126). Optical sheets(128) are arranged in the upper side of the light guide plate. A reflecting plate(122) is arranged in the lower part of the light guide plate. A main support(130) fixes a liquid crystal panel and a backlight unit to the upper side and the lower side. A light diffusing part is formed in the optical sheets.

Description

[0001] LIQUID CRYSTAL DISPLAY DEVICE [0002]

The present invention relates to a liquid crystal display device.

In general, liquid crystal displays (LCDs) have tended to be gradually widened due to their light weight, thinness, and low power consumption. In accordance with this trend, liquid crystal displays are used in office automation equipment, audio / video equipment, and the like. The liquid crystal display device displays a desired image on a screen by adjusting a transmission amount according to image signals applied to a plurality of control switches arranged in a matrix form.

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 surface to irradiate light toward the front of the liquid crystal display panel, thereby realizing an image of identifiable luminance.

1 is an exploded perspective view of a general liquid crystal display device.

As shown in FIG. 1, a general liquid crystal display device module includes a liquid crystal display panel 10, a backlight unit 20, a support main 30, a lower cover 50, and a top cover 40. The liquid crystal display panel 10 plays a key role in image expression and is composed of a color filter substrate and TFT (Thin Film Transistor) substrates 10a and 10b bonded together with a liquid crystal layer interposed therebetween. . A gate printed circuit board 11 for supplying a driving signal and a data printed circuit board 12 for supplying a data signal to the liquid crystal display panel 10 are connected to one edge of the liquid crystal display panel 10. have.

In addition, the backlight unit 20 is provided behind the liquid crystal display panel 10.

In this case, the backlight unit 20 may include the first and second lamps 24a and 24b and the first and second lamps 24a and 24b which are disposed along the longitudinal direction of both sides of the support main 30 facing each other. First and second lamp housings 25a and 25b to be fixed, white or silver reflecting plates 22 seated on the lower cover 50, and the first and second lamps The light guide plate 26 receives the light of 24a and 24b to generate a surface light source, and a plurality of optical sheets 28 interposed therebetween.

The liquid crystal display panel 10 and the backlight unit 20 have top edges formed on the upper and lower sides of the rectangular main frame-shaped support main 30, respectively, and then cover the upper edge of the upper surface of the liquid crystal display panel 10 ( 40 and the upper and lower sides of the backlight unit 20 are respectively coupled to each other by the lower cover 50 to be integrated through the support main 30.

As a result, the light emitted from the first and second lamps 24a and 24b is incident on the light incident portion of the light guide plate 26 and refracted toward the liquid crystal display panel 10, while passing through the plurality of optical sheets 28. It is processed to a high quality of uniform brightness and is incident on the liquid crystal display panel 10. As a result, the liquid crystal display panel 10 displays an image to the outside.

On the other hand, the light guide plate 26 can prevent the flow due to external impact or vibration by the support main 30. That is, the light guide plate 26 is formed with a protrusion 26a, and the protrusion 26a of the light guide plate 26 is fastened to and fixed to the support main 30.

However, light leakage defects frequently occur due to the protrusion 26a of the light guide plate 26.

FIG. 2 is a diagram for describing a region in which light leakage defects occur in a light guide plate region of the liquid crystal display of FIG. 1.

Referring to FIG. 2, first and second lamps 24a and 24b are disposed at both sides of the light guide plate (not shown), and the first and second lamps 24a and 24b are provided in the first and second lamp housings 25a and 25b. It is fixed by). In addition, an optical sheet 28 is disposed above the light guide plate. In the prior art, light leakage defects are generated in the protruding portion 26a of the light guide plate.

This occurs because the protrusions 26a of the light guide plate are formed in a structurally different structure compared to other regions, and the amount of light reflected from the back surface of the light guide plate is different. That is, a plurality of diffusion patterns are formed on the back surface of the light guide plate. In the corner region of the protrusion 26a, light reflection does not occur in comparison with other regions and thus appears relatively dark compared to other regions, resulting in light leakage defects.

Therefore, such a light leakage defect is opposed to a liquid crystal display device requiring a uniform luminance characteristic, thereby lowering the screen quality of the liquid crystal display device.

One object of the present invention is to provide a liquid crystal display device capable of removing light leakage defects on both side surfaces of a light guide plate corresponding to a region where a lamp is not disposed.

In addition, another object of the present invention is to provide a liquid crystal display device that can implement a surface light source of uniform brightness.

The liquid crystal display device of the present invention, the liquid crystal display panel; A light source for supplying a light source to the liquid crystal display panel and including a light guide plate, first and second lamps disposed along both side surfaces of the light guide plate, optical sheets disposed on an upper side of the light guide plate, and a reflective plate disposed below the light guide plate. A backlight unit; And a support main for fixing the liquid crystal display panel and the backlight unit to an upper side and a lower side, respectively, wherein a light diffusing portion is formed in the optical sheet corresponding to the left and right regions of the light guide plate on which the first and second lamps are not disposed. It is characterized by.

Here, protrusions for fixing the light guide plate are formed at left and right edges of the light guide plate on which the first and second lamps are not disposed, and a plurality of diffusion patterns are formed in the light diffusion part in a matrix form, and the width of the light diffusion part is formed. Is characterized in that 3 ~ 7mm in the inner direction with respect to both sides of the optical sheet.

The liquid crystal display of the present invention has the effect of eliminating light leakage defects on both side surfaces of the light guide plate corresponding to the region where the lamp is not disposed.

In addition, the present invention has the effect of realizing a surface light source of uniform brightness by covering the light leakage defective region with the diffusion patterns.

In addition, it is possible to implement a more clear screen quality by covering the edge region of the light guide plate corresponding to the region other than the region where the image is displayed among the liquid crystal display panel of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like numbers refer to like elements throughout.

3 is an exploded perspective view illustrating a liquid crystal display device according to an exemplary embodiment of the present invention, FIG. 4A is a cross-sectional view taken along the line A-A 'of FIG. 3, and FIG. 4B is a cutaway line taken along the line B-B' of FIG. to be.

As shown in FIG. 3, the LCD includes a liquid crystal display panel 110, a backlight unit 120, a support main 130, a lower cover 150, and a top cover 140.

First, the liquid crystal display panel 110 plays a key role in image expression and is composed of a color filter substrate and a TFT substrate 110a and 110b bonded to each other with a liquid crystal layer interposed therebetween. One side edge of the liquid crystal display panel 110 is connected to a gate printed circuit board 111 for supplying a driving signal and a data printed circuit board 112 for supplying a data signal to the liquid crystal display panel 110. The gate and the data printed circuit boards 111 and 112 are brought into close contact with the side of the support main 130 or the bottom of the lower cover 150 during the modularization process.

At this time, although not clearly shown in the drawings under the premise of an active matrix method, a plurality of gate lines and data lines intersect on the inner surface of the TFT substrate 110b, which is commonly referred to as a lower substrate or an array substrate, and a pixel is defined. Thin film transistors (TFTs) are provided at each intersection to be connected one-to-one with the transparent pixel electrodes formed in each pixel.

In addition, the inner surface of the color filter substrate 110a, called the upper substrate, corresponds to each pixel. A black matrix covering the non-display area such as lines, data lines, and thin film transistors is provided. In addition, a transparent common electrode covering them is provided.

Although not clearly shown in the drawings, upper and lower alignment layers (not shown) which determine the initial molecular alignment direction of the liquid crystal are formed at the boundary between the color filter substrate and the TFT substrates 110a and 110b and the liquid crystal layer of the liquid crystal display panel 110. The seal pattern is formed along the edges of both substrates 110a and 110b to prevent leakage of the liquid crystal layer filled therebetween.

In this case, polarizing plates (not shown) are attached to the outer surfaces of the color filter substrate 110a and the TFT substrate 110b, respectively. A backlight unit 120 is provided on a rear surface of the liquid crystal display panel 110 so that the difference in transmittance of the liquid crystal display panel 110 is expressed to the outside.

In this case, the backlight unit 120 may include the first and second lamps 124a and 124b and the first and second lamps 124a and 124b which are disposed along the longitudinal direction of both sides of the support main 130 facing each other. First and second lamp housings 125a and 125b to be fixed, a white or silver reflector 122 seated on the lower cover 150, and the first and second lamps The light guide plate 126 receives the light of 124a and 124b to generate a surface light source, and includes a plurality of optical sheets 128 interposed thereon.

Here, the first and second lamp housings 125a and 125b are configured to fix the light generated by the first and second lamps 124a and 124b while being fixed to the light guide plate 126 in the light incidence region of the light guide plate 126. It serves to concentrate in the direction of the light guide plate 126.

In this case, as the light source, the first and second lamps 124a and 124b may use a fluorescent lamp such as a cold cathode fluorescent lamp or an external electrode fluorescent lamp. Alternatively, in addition to the fluorescent lamp, a light-emitting diode lamp may be used as the lamp, and the lamp housing may be omitted when the light-emitting diode lamp is used.

In particular, a predetermined light diffusing portion 160 is formed in the optical sheet 128 facing the light guide plate 126 of the optical sheets 128 of the present invention. The light guide plate 126 has predetermined protrusions 126a formed on both side surfaces of the light guide plate 126 in which the first and second lamps 124a and 12b are not disposed to prevent flow during assembly. The light diffusing part 160 of the optical sheet 128 is formed in a region overlapping the left and right sides of the light guide plate 126 and the protrusion 126a.

The light diffusion unit 160 blocks a light leakage defect generated in the corner region where the protrusion 126a of the light guide plate 126 is formed.

The liquid crystal display panel 110 and the backlight unit 120 have top edges that are edge-assembled to the upper and lower sides of the rectangular frame-shaped support main 130, respectively, and then surround the top edge of the liquid crystal display panel 110 ( 140 and the lower cover 150 covering the rear surface of the backlight unit 120 are respectively coupled up and down to integrate the support main 130.

As a result, the light emitted from the first and second lamps 124a and 124b is incident on the light incident part of the light guide plate 126 to be refracted toward the liquid crystal display panel 110, and passes through the plurality of optical sheets 128. It is processed to a high quality of uniform brightness and is incident on the liquid crystal display panel 110. As a result, the liquid crystal display panel 110 displays an image to the outside.

A detailed description with reference to FIGS. 4A and 4B is as follows.

First, the A-A 'area is a cross-sectional view of a region where no lamp is disposed, and the liquid crystal display panel 110 is disposed above the support main 130. An upper polarizer 170a and a lower polarizer 170b are attached to the liquid crystal display panel 110, respectively.

In addition, the light guide plate 126, the optical sheet 128, and the reflective plate 122, which are backlight units, are enclosed by the lower cover 150 under the support main 130. The lower cover 150 is fastened by the top cover 140 to fix the liquid crystal display panel 110.

In particular, in the present invention, the light diffusing unit 160 is formed on the rear surface of the optical sheet 128 facing the light guide plate 126 among the optical sheets 128. The light diffusing unit 160 blocks light leakage generated in a corner region not facing the lamp among the four corners of the light guide plate 126.

In the drawing, the light diffusing unit 160 is formed only for the optical sheet 128 facing the light guide plate 126 among the optical sheets 128, but this is not fixed. Accordingly, the light diffusing unit 160 may be formed on the rear surface of all of the optical sheets 128, or the light diffusing unit 160 may be formed only on the rear surface of any one of the optical sheets 128. The light diffusion unit 160 is formed of a plurality of diffusion patterns having a predetermined pitch, and the size of the diffusion patterns becomes smaller as it proceeds inward with respect to the edge edge of the optical sheet 128. A detailed description will be given in 5a and 5b.

In addition, B-B 'area | region is sectional drawing which cut | disconnected the area | region where a lamp is arrange | positioned. As shown in FIG. 4B, the liquid crystal display panel 110 is disposed above the support main 130, and below the optical sheet 128, the light guide plate 126, the reflector plate 122, and the second lamp. 124b and the second lamp housings 125b are accommodated with the lower cover 150 as the bottom surface.

Unlike FIG. 4A, the light diffusing portion is not formed in the optical sheet 128 disposed above the light guide plate 126. The second lamp housing 125b fixes the light from the inner side while fixing the second lamp 124b to supply light to the light incident part region of the light guide plate 126.

5A and 5B are views showing the structure of the light diffusing unit of the optical sheet according to the present invention. As shown in FIGS. 5A and 5B, light diffusion units 160 are formed at both corners of the optical sheet 128. The light diffusion unit 160 is formed to correspond to edges other than the light incident portion of the light guide plate disposed to face the lamp. That is, it is formed to block light leakage generated in the non-light-incident area of the light guide plate.

The light diffusion unit 160 may be formed of a plurality of diffusion patterns 161 and 162. In the diffusion pattern 161 of FIG. 5A, rectangular diffusion patterns are formed in a matrix, and the size of each diffusion pattern 161 is gradually smaller toward the inside with respect to the edge of the optical sheet 128. Formed.

 Correspondingly, referring to FIG. 5B, the diffusion pattern 162 is formed of circular diffusion patterns in a matrix form, and the size of the patterns is gradually smaller toward the inside with respect to the edge of the optical sheet 128. . However, this is not fixed and may be formed by mixing diffusion patterns 161 and 162 having different sizes in order to block light leakage by mixing them within the light diffusion unit 160.

The width D of the light diffusing unit 160 formed on the optical sheet 126 has a deviation of ± 2 mm based on 5 mm. That is, the width of the light diffusion unit 160 is formed in the range of 3 ~ 7mm. The pitch (distance between the patterns) of the diffusion patterns 161 and 162 may have a deviation of ± 10 μm based on 300 μm.

5A and 5B, the shapes of the diffusion patterns 161 and 162 are illustrated in the shape of a rectangle and a circle, but the shapes of the diffusion patterns 161 and 162 may be formed in various shapes such as triangles, rhombuses, and stars. Can be.

FIG. 6 is a plan view illustrating a coupling state between an optical sheet and a light guide plate of a liquid crystal display according to the present invention. As shown in FIG. 124a and 124b are being fixed by the 1st, 2nd lamp housing 125a and 125b. The protrusion 126a of the light guide plate is formed in each corner region perpendicular to the light incident region of the light guide plate, and the light diffusion unit 160 is formed in the left and right corner regions of the optical sheet 128 so as to correspond to the light guide plate. Therefore, the light diffusing unit 160 of the optical sheet 128 blocks the light leakage defects generated in the protrusion 126a of the light guide plate, so that a uniform surface light source can be supplied to the liquid crystal display panel.

In the present invention, the size of the diffusion patterns formed in the light diffusion unit 160 of the optical sheet 128 is varied so that the luminance difference does not occur in the corner region of the liquid crystal display panel. That is, the size of the diffusion patterns formed in the left and right corner regions of the optical sheet 128 is increased or increased to prevent light leakage defects from occurring in the non-display area while decreasing the size or density of the diffusion patterns toward the display area. Lowered to have a uniform luminance characteristics.

7 to 9 illustrate the structure of a light guide plate according to other embodiments of the present invention.

Referring to FIG. 7, in order to prevent light leakage in the area of the protrusion 126a of the light guide plate 126, the reflective tape 200 is attached to the edge side of the light guide plate 126 on which the protrusion 126a is formed. The reflective tape 200 is a scattering agent of CaCO ₃ (Calcium carbonate), BaSO ₄ , silica, Calcium phosphate, TiO 2, SiO 2, CaCo 3, SnO 2, Mb 2 O 5, ZnO 2, MgF 2, CeO 2, Al 2 O 3, HfO 2, Na 3 LaF 6, and LaF 6. One can contain materials. In addition, the reflective tape 200 may use a polarizing plate material.

The reflective tape 200 is formed on the left and right side surfaces of the light guide plate 126 on which the lamps are not disposed and on the side surface of the protrusion 126a. Accordingly, the reflective tape 200 improves light leakage defects by guiding all the light leaked through the left and right side surfaces of the light guide plate 126 and the side surface of the protrusion 126a toward the inside of the light guide plate 126.

8A and 8B, lower left and right edges of the light guide plate 126 including the protrusion 126a and lower edges of the protrusion 126a in order to prevent light leakage in the protrusion 126a region of the light guide plate 126. A predetermined rounding surface 250 is formed in the. Looking at the light guide plate 126 in the X-X 'direction, it can be seen that a predetermined rounding surface 250 is formed in the lower edge region of the light guide plate 126. The rounding surface 250 is formed on both side surfaces and the protrusion 126a of the light guide plate 126 in which the lamp is not disposed.

As described above, when the rounding surface 250 is formed in the lower edge region of the light guide plate 126, the light traveling to the inside of the light guide plate 126 is reflected, scattered, and refracted, and then proceeds to the inside of the light guide plate 126. ) Does not proceed to the upper side of the light guide plate 126 is formed can remove the light leakage defect.

Referring to FIG. 9, expansion portions 122a for preventing light leakage are formed in left and right regions of the reflection plate 122 disposed under the light guide plate 126, and the expansion portions 122a are folded to form the light guide plate 126. The protrusion 126a was attached to the side on which the protrusion was formed. The extension part 122a of the reflector plate 122 extends to both side edges and the protrusion part 126a area of the light guide plate 126 in which the lamp is not disposed, and the extension part 122a extends to both side surfaces and the protrusion part 126a of the light guide plate 126. Is attached on the side.

Accordingly, the light having total reflection inside the light guide plate 126 does not have light leakage to the lower side of the light guide plate 126 on the surface where the protrusion 126a is formed, and all of the light inside the light guide plate 126 or the upper surface of the light guide plate 126. Proceeds to generate a surface light source of uniform brightness.

As a result, light leakage defects occurring in the protruding portion 126a of the light guide plate 126 may be removed.

In addition, in the present invention, the light diffusing unit is formed on the optical sheet together with the light guide plate and the reflector plate structures of FIGS. 7 to 9, or when only the light guide plate and the reflector plate structures of FIGS. 7 to 9 are used. The light diffusion unit may not be formed. On the contrary, when the light diffusion part is formed on the optical sheet, the light diffusion plate and the reflection plate may be used without changing the structure. That is, according to the application model of the liquid crystal display device, only the light diffusing part forming embodiment of the optical sheet may be used, and the light leakage defect may be removed by selectively mixing the light guide plate and the reflecting plate structure and the optical diffusing part forming optical sheet together. have.

1 is an exploded perspective view of a general liquid crystal display device.

FIG. 2 is a diagram for describing a region in which light leakage defects occur in a light guide plate region of the liquid crystal display of FIG. 1.

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

4A is a cross-sectional view taken along the line AA ′ of FIG. 3.

4B is a cross-sectional view taken along line BB ′ of FIG. 3.

5A and 5B are views showing the structure of the light diffusing unit of the optical sheet according to the present invention.

6 is a plan view illustrating a coupling state between the optical sheet and the light guide plate of the liquid crystal display according to the present invention.

7 to 9 illustrate the structure of a light guide plate according to other embodiments of the present invention.

 (Explanation of reference numerals for the main parts of the drawings)

110: liquid crystal display panel 120: backlight unit

130: support main 122: reflector

126: Light guide plate 126a: protrusion

128: optical sheet 160: light diffusion unit

Claims (10)

A liquid crystal display panel; A light source for supplying a light source to the liquid crystal display panel and including a light guide plate, first and second lamps disposed along both side surfaces of the light guide plate, optical sheets disposed on an upper side of the light guide plate, and a reflective plate disposed below the light guide plate. A backlight unit; And A support main fixing the liquid crystal display panel and the backlight unit to an upper side and a lower side, respectively; And a light diffusing portion is formed in the optical sheet corresponding to the left and right regions of the light guide plate on which the first and second lamps are not disposed. The liquid crystal display of claim 1, wherein protrusions for fixing the light guide plate are formed at left and right edges of the light guide plate on which the first and second lamps are not disposed. The liquid crystal display of claim 1, wherein a plurality of diffusion patterns are formed in a matrix in the light diffusion unit. The liquid crystal display device according to claim 1, wherein the width of the light diffusing portion is 3 to 7 mm in an inward direction with respect to both edges of the optical sheet. 3. The liquid crystal display device according to claim 2, wherein reflective tapes are attached to the left and right side surfaces of the light guide plate on which the first and second lamps are not disposed and the side surfaces of the protrusions. The liquid crystal display of claim 2, wherein a rounding surface is formed at left and right lower corners and lower lower corners of the light guide plate on which the first and second lamps are not disposed. 3. The liquid crystal display of claim 2, wherein an extension part is formed on left and right sides of the light guide plate on which the first and second lamps are not disposed and on side surfaces of the light guide plate. The liquid crystal display device according to claim 3, wherein the size of the diffusion patterns formed in the light diffusion portion has a different size. The liquid crystal display device according to claim 3, wherein the diffusion patterns formed on the light diffusion portion are formed to have a small size in the inward direction with respect to the left and right edges of the optical sheet. The liquid crystal display of claim 1, wherein the light diffusing portion of the optical sheet is formed on a rear surface of the optical sheet which is in opposition to the light guide plate.

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