KR20030060023A - Liquid crystal display apparatus - Google Patents

Abstract

PURPOSE: A liquid crystal display is provided to realize light equalized in brightness distribution without extending a light guide plate, thereby reducing the size and weight of the liquid crystal display. CONSTITUTION: A plurality of point light sources(210) generates first light. A light guide plate(220) is made up of an incident surface(221) to which the first light is projected, a specular surface(222) for reflecting the first light, and a projecting surface(223) facing the specular surface, so that the light guide plate guides the first light to the projecting surface for projecting second light. A brightness enhancing film(250) is partially arranged on the projecting surface for enhancing the brightness of a part adjacent to the incident surface for projecting the second light as third light equalized in brightness distribution. A liquid crystal display panel(110) receives the third light for displaying an image.

Description

Liquid crystal display device {LIQUID CRYSTAL DISPLAY APPARATUS}

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device capable of realizing a thinner and lighter weight and improving luminance uniformity.

Recently, information processing devices have been rapidly developed to have various forms and functions, and faster information processing speed. Such information processing apparatuses require display devices for displaying processed information.

As a display device, a liquid crystal display device having a light weight, a small size, and a small space is mainly developed along with the generalization of a portable device, and is widely used as a display device of a computer monitor, a home wall television, and other information processing devices.

In general, a liquid crystal display device converts into a different molecular arrangement by applying a voltage to a specific molecular arrangement of the liquid crystal, and the optical properties such as birefringence, photoreactivity, dichroism and light scattering characteristics of the liquid crystal cell that emits light by the molecular arrangement It converts a change into a visual change, and is a display apparatus using the modulation of the light by a liquid crystal cell.

In this case, since the liquid crystal used in the liquid crystal display device is a passive optical element that does not generate light by itself, an optical supply device for supplying light to the liquid crystal is inevitably required. Accordingly, the LCD includes a liquid crystal display panel for displaying an image and a backlight assembly for providing light to the liquid crystal display panel.

However, in such a liquid crystal display, most of the power supply (approximately 70%) is consumed in the backlight assembly. Therefore, in recent years, a method of reducing power consumption in the backlight assembly has been studied to minimize power consumption of the liquid crystal display.

In particular, studies on reducing the power consumption of the liquid crystal display device in the rechargeable portable device of 1 inch to 5 inches are continuing. Thus, in the 1 to 5 inch rechargeable portable devices, instead of the cold cathode ray tube lamps generally used in the backlight assembly, LEDs in the form of point light sources having low power consumption are used.

1 is a view showing a conventional backlight assembly.

Referring to FIG. 1, the backlight assembly 30 includes a plurality of light sources 10 generating first light and a light guide plate 20 for guiding the first light to emit second light.

LEDs having a form of point light sources are generally used for the plurality of light sources 10.

On the other hand, the light guide plate 20 is provided with a plurality of light sources 10, the incident surface 21, the first light is incident, a reflection surface (not shown) for reflecting the first light and the incident surface ( And an exit surface 23 for facing the reflecting surface 21 between them and for emitting the second light reflected by the reflecting surface.

The first light generated from the plurality of light sources 10 is incident through the incident surface 21. At this time, since the plurality of light sources 10 are point light sources, the irradiation distance of the first light is narrow. That is, the first light is an area between the first boundary line 21b tilted 45 ° to the left and the second boundary line 21c tilted 45 ° to the right based on the normal line 21a of the incident surface 21. Hereinafter, while incident with 100% efficiency in the first region W, it is incident with efficiency of about 70% in the other region (hereinafter referred to as the second region D). Therefore, the second region D has a lower luminance than the first region W, so that a difference in luminance occurs between the first and second regions W and D. FIG. Therefore, the second light guided and emitted by the light guide plate 20 has a non-uniform luminance distribution.

In order to solve such non-uniform luminance distribution, the following structure is conventionally employ | adopted.

FIG. 2 is a view illustrating an improved structure of the backlight assembly illustrated in FIG. 1.

Referring to FIG. 2, the backlight assembly 31 includes a plurality of light sources 10 generating first light and a light guide plate 40 for guiding the first light. The light guide plate 40 is formed of a first region W having a relatively high luminance and a second region D having a relatively low luminance at an incident surface side in which the plurality of light sources 10 are provided.

In this case, the light guide plate 40 extends by the luminance non-uniformity region B where the first region W and the second region D are repeatedly generated. That is, the light guide plate 40 extends from the surface 42 positioned opposite the incident surface 41 by the width w1 of the luminance non-uniformity region B. Therefore, the image is displayed only in the effective display area A, with the remaining area except for the luminance non-uniformity area B being the effective display area A. FIG.

As such, the size of the light guide plate 40 is increased by 'w1' than the light guide plate 20 shown in FIG. 1, so that the overall size of the liquid crystal display is also increased by 'w1'.

Such a structure can secure luminance uniformity, but considering that a liquid crystal display device adopting such a structure is a portable device, an increase in volume and weight of the liquid crystal display device causes another problem that it is difficult to carry. .

Therefore, at present, there is a demand for a technology capable of securing luminance uniformity while minimizing an increase in volume and weight.

Accordingly, an object of the present invention is to provide a liquid crystal display device that can realize thinner and lighter weight and improve luminance uniformity.

1 and 2 are views illustrating a conventional backlight assembly.

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

4 is a perspective view specifically showing the brightness enhancement film shown in FIG. 3.

5 is a perspective view specifically showing a brightness enhancement film according to another embodiment of the present invention.

6 is a plan view illustrating a state in which the brightness enhancement film illustrated in FIG. 5 is seated on the light guide plate.

7 is a plan view illustrating a state in which the brightness enhancement film illustrated in FIG. 5 is seated on both side portions of the light guide plate.

8 is a perspective view specifically showing a brightness enhancement film according to another embodiment of the present invention.

FIG. 9 is a perspective view specifically showing a mold frame to be combined with the brightness enhancement film shown in FIG. 8.

FIG. 10 is an enlarged perspective view illustrating a portion E shown in FIG. 9.

FIG. 11 is a view illustrating a state in which the brightness enhancement film illustrated in FIG. 8 is coupled to a mold frame.

12 is a perspective view specifically showing a brightness enhancement film according to another embodiment of the present invention.

FIG. 13 is a perspective view specifically showing a mold frame to be combined with the brightness enhancement film shown in FIG. 12.

FIG. 14 is a view illustrating a state in which the brightness enhancement film illustrated in FIG. 12 is coupled to a mold frame.

According to an exemplary embodiment of the present invention, a liquid crystal display device includes: a point light source for generating first light, an incident surface on which the first light is incident, a reflective surface for reflecting the first light, and the incident surface A light guide plate configured to face the reflection surface with the light interposed therebetween, the light guide plate guiding the first light toward the emission surface to emit a second light, and partially disposed on the emission surface adjacent to the entrance surface; And a luminance-enhanced film and the third light provided to enhance the luminance of the portion adjacent to the incident surface to emit the second light emitted through the emission surface as a third light having a uniform luminance distribution. And a liquid crystal display panel for displaying.

The luminance-enhanced film is disposed on the emission surface corresponding to the area between the point light sources, the plurality of first luminance-enhanced film and the emission surface having a triangular shape that becomes narrower away from the point light source. It is disposed on and formed integrally with the plurality of first brightness enhancement film, it consists of a second brightness enhancement film for connecting the plurality of first brightness enhancement film.

According to the present invention, the second light emitted from the light guide plate having a non-uniform brightness distribution is strengthened in a region having a relatively low luminance through a brightness enhancement film partially provided on the emission surface adjacent to the incident surface. Let's do it. Thus, the second light emitted from the light guide plate is emitted as the third light having a uniform luminance distribution. Therefore, the liquid crystal display device can realize a thinner and lighter weight, and can secure luminance uniformity.

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

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

Referring to FIG. 3, the LCD 500 includes a display unit 100 for displaying an image and a backlight assembly 100 for supplying uniform light to the display unit 100.

The display unit 100 includes a liquid crystal display panel 110 for displaying an image, and a driving circuit unit for providing image data signals and driving signals from the outside to the liquid crystal display panel 110. In this case, the driving circuit unit includes a data side printed circuit board 120 and a gate side printed circuit board 130.

The liquid crystal display panel 110 includes a TFT substrate 112 on which a thin film transistor and a pixel electrode are formed, a color filter substrate 114 on which RGB pixels and a common electrode are formed, and between the TFT substrate 112 and the color filter substrate 114. Injected liquid crystal layer.

A thin film transistor (not shown) is formed on the TFT substrate 112 in a matrix form, and a source electrode of the thin film transistor is formed on a plurality of data lines (not shown) extending in a column direction on the TFT substrate 112. Common connection in the column direction. In addition, the gate electrode of the thin film transistor is commonly connected in a row direction to a plurality of gate lines (not shown) formed in the row direction on the TFT substrate 112. In addition, the drain electrode of the thin film transistor is connected to the pixel electrode (not shown).

One end of the plurality of data lines is coupled to a data side tape carrier package (TCP, 140) on which a data driving chip is mounted, and one end of the plurality of gate lines is a gate side TCP on which a gate driving chip is mounted. Combined with 150.

The data side TCP 140 is coupled to the data side printed circuit board 120 to provide image data signals from the data side printed circuit board 120 to the plurality of data lines at appropriate times. In addition, the gate side TCP 150 is coupled to the gate side printed circuit board 130 to provide a gate driving signal from the gate side printed circuit board 130 to the plurality of gate lines.

The backlight assembly 200 includes a plurality of light sources 210 generating first light and a light guide part for guiding the first light to the liquid crystal display panel 110. In detail, the light guide part includes a light guide plate 220 provided at one side of the plurality of light sources 210, a reflective plate 240 provided under the light guide plate 220, and a plurality of light guide plates 240. Optical films 250, 230.

The plurality of light sources 210 are composed of light emitting devices such as LEDs having a point light source shape.

On the other hand, the light guide plate 220 is provided with a plurality of light sources 210, the incident surface 221, the first light is incident, the reflective surface 222 for reflecting the first light to the second light and the An emission surface 223 is disposed to face the reflection surface 222 with the incident surface 221 therebetween to emit the second light. Therefore, the light guide plate 220 guides the first light to emit the second light through the emission surface 223.

The reflective plate 240 reflects the third light leaked by the reflective surface 222 of the light guide plate 220 back to the light guide plate 220 to increase the amount of the second light.

The plurality of optical films 230 and 250 may include a first luminance enhancing film 250, a diffusion film 231, a light collecting film 232, and a protective film 233.

The first luminance enhancing film 250 is partially disposed on the exit surface 223 adjacent to the incident surface 221 of the light guide plate 220. The light guide plate 220 is divided into a first region W having relatively high luminance and a second region D having a relatively low luminance. In this case, when viewed from the top of the exit surface 223, the first luminance-enhanced film 250 is formed in the same shape as the second region D and is disposed on the exit surface 223. That is, the first luminance enhancing film 250 enhances the luminance in the second region D to compensate for the luminance difference between the first region W and the second region D. FIG. do.

A detailed description of the first luminance enhancing film 250 will be described later with reference to the drawings.

Meanwhile, the diffusion film 231 disperses the fourth light incident from the light guide plate 220 to prevent the fifth light emitted from the diffusion film 231 from being partially concentrated. A plurality of triangular prisms (not shown) are formed on the top surface of the light collecting film 232, respectively. The light collecting film 232 narrows the viewing angle of the fifth light diffused by the diffusion film 231 to improve front brightness. The protective film 233 protects the surface of the light collecting film 232 and prevents moire and rainbow phenomenon caused by the light collecting film 232.

The display unit 100 and the backlight assembly 200 configured as described above are accommodated in the mold frame 300. In detail, the mold frame 300 includes a reflecting plate 240, a light guide plate 220, a first luminance enhancing film 250, a diffusion film 231, a light collecting film 232, and a protective film 233. do. Thereafter, the liquid crystal display panel 110 is seated on the protective film 233.

On the other hand, a top chassis 400 for fixing the backlight assembly 200 and the display unit 100 accommodated in the mold frame 300 by coupling to the mold frame 300 is provided.

4 is a plan view illustrating a state in which the luminance-enhanced film illustrated in FIG. 3 is disposed on a light guide plate.

Referring to FIG. 4, the light guide plate 220 includes the incident surface 221 through which the first light is incident, the reflective surface 222 for reflecting the first light, and the incident surface 221 between the half. It consists of an exit surface 223 facing the slope 222.

In this case, the plurality of first luminance-enhanced films 250 are disposed on the emission surface 223 adjacent to the incident surface 221. The plurality of first luminance enhancing films 250 are disposed on the emission surface 223 so as not to overlap the plurality of light sources 210 when viewed from the plurality of light sources 210.

Specifically, since the plurality of light sources 210 are point light sources, the irradiation distance of the first light generated from the plurality of light sources 210 is narrow. That is, the first light is an area between the first boundary line 221b tilted 45 ° to the left and the second boundary line 221c tilted 45 ° to the right based on the normal line 221a of the incident surface 221, That is, the light is incident with 100% efficiency in the first region (W). However, in the other area, that is, the second area D, the light is incident with an efficiency of about 70%.

Therefore, while the luminance is relatively high in the first region W, the luminance is lower than that of the first region W in the second region D, so that the first region W and the second region D are lower. Difference in luminance occurs. When viewed from the side of the plurality of light sources 210, the second region D is repeatedly formed in an area that does not overlap with the plurality of light sources 210. In addition, when viewed from the liquid crystal display panel 110 side, the second region D has a triangular shape that becomes narrower as it moves away from the plurality of light sources 210.

In this case, the plurality of first luminance enhancing films 250 provided to enhance the luminance of the second light emitted from the second region D are formed in the same shape as the second region D, and thus It is disposed on the exit surface 223 including two regions (D). Therefore, the first luminance enhancing film 250 enhances the luminance in the second region D to compensate for the luminance difference between the first region W and the second region D. FIG.

For this reason, the third light having a uniform luminance distribution is emitted from the emission surface 223 of the light guide plate 220. Accordingly, the entire area may be used as the effective display area A without extending the length of the light guide plate 220.

5 is a perspective view specifically showing a brightness enhancement film according to another embodiment of the present invention. FIG. 6 is a plan view illustrating a state in which the luminance-enhanced film illustrated in FIG. 5 is disposed on a light guide plate.

5 and 6, a connection film 261 for connecting the second luminance enhanced film 260 and the second luminance enhanced film 260 is provided on the emission surface 223 of the light guide plate 220. do. The connection film 261 is integrally formed on the second luminance enhancement film 260, and connects the second luminance enhancement film 260 spaced apart from the emission surface 223 to each other. do.

In this case, the second brightness enhancement film 260 is disposed on the remaining second area D which is not covered by the connection film 261. Specifically, when the width of the second region D, that is, the length from the incident surface 221 of the light guide plate 220 to the surface opposite to the incident surface 221 is 'w1', the connection film 261 has a width of 'w2', and the second luminance-enhanced film 260 has 'w3' obtained by subtracting the width w2 of the connection film 161 from the width w1 of the second area D. Has a width of '.

Therefore, the width w3 of the second luminance enhanced film 260 is smaller than the width w1 of the first luminance enhanced film 250 illustrated in FIG. 4.

On the other hand, since the connection film 261 extends from one side of the light guide plate 220 to the other side opposite to the one side, the first region W having relatively high brightness and the relatively low brightness The second area D is simultaneously covered. Therefore, the luminance of the second light is not uniform in the portion covered by the connection film 261.

Therefore, the connection film 261 is preferably formed to be thin enough not to affect the luminance non-uniformity of the second light while maintaining the thickness enough to connect the second brightness enhancement film 260.

More preferably, in order to solve the luminance non-uniformity caused by the connection film 261, the light guide plate 220 is extended by the width w2 of the connection film 261. That is, the light guide plate 220 extends to a surface 224 positioned opposite to the incident surface 221. Therefore, the remaining area except the area where the connection film 261 is disposed is defined as an effective display area A` capable of displaying an image.

As described above, the structure increases the size of the light guide plate 220, but the size of the light guide plate 220 is reduced compared to the conventional structure, which is increased by the width w1 of the second region D. It is possible to prevent an increase in the size and weight of the liquid crystal display device 500.

The second brightness enhancement film 260 is disposed on the side where the plurality of light sources 210 are provided. As shown in FIG. 7, when the plurality of light sources 210 are provided at one side 221 of the light guide plate 220 and the other side 224 facing the one side 221, respectively, the second luminance-enhanced film 260 is disposed on the emission surface 223 adjacent to one side 221 and the other side 224 of the light guide plate 220, respectively.

In addition, although not shown in the drawings, when the plurality of light sources are provided on four side surfaces of the light guide plate, the second luminance-enhanced film is also disposed on the emission surface adjacent to the four sides.

8 is a perspective view showing in detail the luminance-enhanced film according to another embodiment of the present invention. 9 is a perspective view specifically showing a mold frame to be combined with a brightness enhancement film. FIG. 10 is an enlarged perspective view illustrating an enlarged portion E shown in FIG. 9.

Referring to FIG. 8, a third brightness enhancement film 270 is disposed on the emission surface 223 of the light guide plate 220 adjacent to the incident surface 221. In this case, the third brightness enhancement film 270 includes first and second fixing parts 271 and 272 extending from both ends, respectively. First and second fixing holes 271a and 272a penetrating the first and second fixing portions 271 and 272 are formed in the first and second fixing portions 271 and 272, respectively.

Meanwhile, referring to FIGS. 9 and 10, the mold frame 300 is formed of four sidewalls disposed to surround the bottom surface 310 and the bottom surface 310. At this time, the first and second sidewalls 320 and 330 of the mold frame 300 respectively corresponding to both ends of the third luminance-enhanced film 270 as the storage space F of the mold frame 300, respectively. Protruding first and second stepped portions 321 and 331 are formed. First and second fixing protrusions 321a and 332a are formed on upper surfaces of the first and second stepped portions 321 and 331 to correspond to the first and second fixing holes 271a and 272a, respectively. .

FIG. 11 is a plan view illustrating a state in which the luminance-enhanced film shown in FIG. 8 is combined with a mold frame.

Referring to FIG. 11, when the light guide plate 220 is seated in the receiving space F of the mold frame 300, the third luminance-enhanced film 270 is formed on the light guide plate 220. It is disposed on the exit surface 223 in contact with the. When the third luminance enhancing film 270 is accommodated in the mold frame 300, the first and second fixing protrusions 321a and 331a formed in the mold frame 300 may include the third luminance enhancing film ( It is fitted into the first and second fixing holes (271a, 272a) formed in the 270. Thus, the third brightness enhancing film 270 is firmly fixed to the mold frame 300.

As a result, the third luminance-enhanced film 270 may be prevented from flowing by an impact from the outside.

12 is a perspective view showing in detail a brightness enhancement film according to another embodiment of the present invention, Figure 13 is a perspective view showing in detail a mold frame to be combined with the brightness enhancement film shown in FIG.

Referring to FIG. 12, a fourth brightness enhancing film 280 is disposed on the exit surface 223 of the light guide plate 220 adjacent to the incident surface 221. In this case, the fourth luminance-enhanced film 280 includes first and second protrusions 281 and 282 extending from both ends. In the present exemplary embodiment, the first and second protrusions 281 and 282 are formed in a rectangular shape when viewed from the side of the light guide plate 220. However, the first and second protrusions 281 and 282 may have a shape. The mold frame 300 may be variously modified and applied within a range having a bonding force enough to fix the fourth luminance-enhanced film 280.

Meanwhile, referring to FIG. 13, the mold frame 300 includes four sidewalls disposed to surround the bottom surface 310 and the bottom surface 310. In this case, the first and second sidewalls 320 and 330 of the four sidewalls of the mold frame corresponding to the first and second protrusions 281 and 282 of the fourth luminance-enhanced film 280 may be formed. The first and second fixing grooves 321 and 331 for accommodating and fixing the protrusions 281 and 282 are formed.

In this case, the first and second fixing grooves 321 and 331 are formed by recessing to the predetermined depth from the first and second side walls 320 and 330. In this case, the depth in which the first and second fixing grooves 321 and 331 are recessed is formed to be the same as the height in which the first and second protrusions 281 and 382 protrude.

FIG. 14 is a view illustrating a state in which the brightness enhancement film illustrated in FIG. 12 is coupled to a mold frame.

Referring to FIG. 14, when the light guide plate 220 is accommodated in the mold frame 300, the fourth brightness enhancing film 280 is seated on the light guide plate 220. In this case, the first and second protrusions 281 and 282 of the fourth luminance-enhanced film 280 are accommodated in the first and second fixing grooves 321 and 331 of the mold frame 300. The mold frame 300 and the fourth brightness enhancing film 280 are firmly coupled.

Therefore, even if an impact is applied from the outside after the fourth luminance-enhanced film 280 is seated on the exit surface 223 of the light guide plate 220, the first and second protrusions 281 and 282 may be disposed in the The fourth luminance-enhanced film 280 is prevented from flowing by engaging the first and second fixing grooves 321 and 331.

According to the present invention, the liquid crystal display includes a brightness enhancement film partially disposed on the exit surface adjacent to the incident surface of the light guide plate. The brightness enhancing film is emitted from the light guide plate, and is disposed on a region having a relatively low brightness to emit the second light having a non-uniform brightness distribution as the third light having a uniform brightness distribution to enhance brightness.

Accordingly, the liquid crystal display device includes a brightness enhancing film capable of enhancing brightness in a region having low luminance, thereby providing light having a uniform luminance distribution without extending the light guide plate by a region where the luminance is uniform. Can be provided to As a result, the liquid crystal display device can be made thinner and lighter, and luminance uniformity can be ensured.

Although described with reference to the examples, those skilled in the art can understand that the present invention can be variously modified and changed without departing from the spirit and scope of the invention described in the claims below. There will be.

Claims (7)

Point light source for generating a first light; An incident surface on which the first light is incident, a reflective surface for reflecting the first light, and an exit surface facing the reflective surface with the incident surface interposed therebetween, guiding the first light to the exit surface side; A light guide plate for emitting the second light; The second light emitted through the light exit surface is partially disposed on the light exit surface adjacent to the light incident surface, and the light emitted through the light exit surface is enhanced as the third light having a uniform luminance distribution. Brightness enhancement film; And And a liquid crystal display panel for receiving the third light to display an image. The method of claim 1, wherein the brightness enhancement film, A plurality of first luminance-enhanced films disposed on the emission surface corresponding to regions between the point light sources and having a triangular shape that becomes narrower as the distance from the point light sources increases; And And a second brightness enhancement film disposed on the emission surface and integrally formed with the plurality of first brightness enhancement films to connect the plurality of first brightness enhancement films. The liquid crystal display device of claim 2, further comprising a mold frame accommodating the point light source, the light guide plate, the brightness enhancement film, and the liquid crystal display panel. 4. The liquid crystal display of claim 3, wherein the luminance-enhanced film further comprises fixing portions extending from both ends thereof. 5. The liquid crystal display of claim 4, wherein fixing holes are formed in the fixing parts to penetrate the fixing parts, respectively. The liquid crystal display of claim 5, wherein fixing protrusions are formed on both sidewalls of the mold frame so as to be coupled to the fixing holes to prevent the luminance-enhanced film from flowing. 5. The liquid crystal display of claim 4, wherein a fixing groove is formed by cutting both side walls of the mold frame to a predetermined size, and the fixing groove is coupled to the fixing part to prevent the luminance-enhanced film from flowing. Device.