KR20080012613A - Liquid crystal display apparatus - Google Patents

Abstract

An LCD(Liquid Crystal Display) is provided to enable light transmitted to an LCD panel to be reflected by a reflection member so as to be transmitted to a light guide plate, thereby reducing generation of light leakage as loss of a part of the light emitted from a point light source and accordingly improving usage efficiency of the light. An inside of a mold frame(100) is opened, and a light guide plate(200) is disposed within the mold frame. A receiving member(300) is coupled with the mold frame and covers a lower part of the light guide plate. An LCD(Liquid Crystal Display) panel(400) is disposed in an upper part of the light guide plate and displays images. An FPCB(Flexible Printed Circuit Board)(500) is connected with one surface of the LCD panel, and bent from one surface of the LCD panel to the other surface of the LCD panel to be fixed. At least one point light source(600) is electrically connected with the FPCB, and generates light by being disposed in an light apply surface of the light guide plate. A reflection member(700) is formed on the FPCB corresponding to an area between the point light source and the light guide plate, and reflects the light generated from the point light source to the light apply surface.

Description

Liquid crystal display device {LIQUID CRYSTAL DISPLAY APPARATUS}

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

FIG. 2 is a cross-sectional view illustrating a coupling relationship of a liquid crystal display device taken along the line II ′ of FIG. 1.

3 is a bottom perspective view illustrating a coupling relationship between a mold frame and a point light source illustrated in FIG. 1.

4 is a cross-sectional view of the LCD device cut along the line II ′ of FIG. 1.

5 is a cross-sectional view illustrating a liquid crystal display and a path of light according to an embodiment of the present invention.

6 is a cross-sectional view illustrating a liquid crystal display and a path of light according to another embodiment of the present invention.

7 is a cross-sectional view illustrating a liquid crystal display and a light path according to another embodiment of the present invention.

FIG. 8 is a perspective view partially cutaway of the flexible circuit board, the point light source, and the reflective member illustrated in FIG. 7.

Explanation of symbols on the main parts of the drawings

100 mold frame 110 light source mounting portion

200: light guide plate 300: storage member

400: liquid crystal display panel 500: flexible circuit board

510: adhesive member 520: signal supply

600: point light source 700: reflective member

1000: liquid crystal display

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device which can improve display quality by preventing occurrence of light leakage.

In general, various electronic devices such as a mobile communication terminal, a digital camera, a notebook computer, a monitor, a TV, and the like include an image display device for displaying an image. Various types may be used as the image display device, but a flat display device having a flat plate shape is mainly used, and a liquid crystal display (LCD) is widely used among the flat display devices.

Such a liquid crystal display device (LCD) is a flat panel display device that displays an image using liquid crystal, and is thinner and lighter than other flat panel display devices, and has a low driving voltage and low power consumption. There is an advantage in that it is widely used throughout the industry.

The liquid crystal display device includes a liquid crystal display panel, a printed circuit board and a point light source. The liquid crystal display panel displays an image using light, and the printed circuit board is connected to one side of the liquid crystal display panel, and is bent from one side of the liquid crystal display panel to the other side to be fixed. Recently, in order to reduce the size and weight of a product and to reduce manufacturing costs, a point light source is directly mounted on a printed circuit board so as to be electrically connected to the printed circuit board.

On the other hand, when the printed circuit board is bent and fixed from one surface of the liquid crystal display panel to the other surface, a space is generated between the point light source and the light guide plate by a coupling tolerance between the point light source and the light guide plate. At this time, the light generated from the point light source is not provided to all of the liquid crystal display panel, and light leakage occurs such that light is transmitted through a printed circuit board made of a thin and semitransparent material. Therefore, a problem arises in that the light utilization efficiency is lowered and the display quality of the liquid crystal display device is lowered.

Accordingly, the present invention has been made in view of such a conventional problem, and the present invention provides a liquid crystal display device which can improve the display quality by preventing light leakage.

A liquid crystal display device according to an aspect of the present invention described above includes a mold frame, a light guide plate, a housing member, a liquid crystal display panel, a flexible circuit board, a point light source, and a reflective member.

The mold frame is opened therein, and the light guide plate is disposed in the mold frame. The accommodation member is coupled to the mold frame to cover the lower portion of the light guide plate. The liquid crystal display panel is disposed on the light guide plate to display an image. The flexible circuit board is connected to one surface of the liquid crystal display panel, and is bent from one surface of the liquid crystal display panel to the other surface of the liquid crystal display panel. The point light source is electrically connected to the flexible circuit board, is disposed on an incident surface of the light guide plate to generate light, and is formed at least one. The reflective member is formed on a flexible circuit board corresponding to a region between the point light source and the light guide plate, and reflects the light generated from the point light source to the incident surface.

The reflective member is disposed in parallel with the point light source, and at least one reflection member is formed, and the reflective member is spaced apart by a predetermined distance.

The reflective member is coded with white ink and formed by the silk screen method. In addition, the reflective member may be made of a metal material.

The flexible circuit board includes a signal supply unit for supplying a driving signal to the point light source, and a portion of the signal supply unit is formed in an area corresponding to the reflective member. The signal supply part is made of a metal material.

The point light source comprises one or more light emitting diodes. The flexible circuit board is fixed to the liquid crystal display panel through an adhesive member. For example, the adhesive member is a double sided tape.

The mold frame includes a light source seating portion on which the point light source is mounted.

The liquid crystal display device may include a reflective sheet disposed under the light guide plate to reflect light from the light guide plate to an emission surface, and an optical sheet disposed above the light guide plate to diffuse and collect light emitted from the emission surface of the light guide plate. Includes more.

According to the liquid crystal display device, light leakage phenomenon can be prevented from occurring to improve display quality of the liquid crystal display device.

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

1 is an exploded perspective view illustrating a liquid crystal display according to an exemplary embodiment of the present invention. FIG. 2 is a cross-sectional view illustrating a coupling relationship of a liquid crystal display device cut along the line II ′ of FIG. 1, and FIG. 3 is a bottom perspective view illustrating a coupling relationship between a mold frame and a point light source shown in FIG. 1.

Referring to FIG. 1, a liquid crystal display device 1000 according to an exemplary embodiment may include a mold frame 100, a light guide plate 200, an accommodation member 300, a liquid crystal display panel 400, and a flexible circuit board 500. ), A point light source 600, and a reflective member 700. In addition, the liquid crystal display 1000 may further include a reflective sheet 210 and an optical sheet 220.

The mold frame 100 is opened inside. For example, the mold frame 100 has a rectangular frame shape with an opening therein. The mold frame 100 has a space for accommodating the light guide plate 200, the reflective sheet 210, and the optical sheet 220. The mold frame 100 is made of, for example, a plastic material.

In addition, the mold frame 100 includes a light source mounting part 110 on which the point light source 600 is mounted. The light source seating unit 110 has an accommodation space for accommodating the point light source 600. The light source seating part 110 forms a space in which a portion of the inner surface of the mold frame 100 forms a groove to accommodate the point light source 600. Accordingly, the light source seating unit 110 accommodates and fixes the point light source 600, thereby preventing the point light source 600 from flowing out.

The light guide plate 200 is disposed inside the mold frame 100. In addition, the light guide plate 200 changes the light incident from the point light source 600 into light in the form of a surface light source and emits the light. Therefore, the light guide plate 200 includes an entrance surface to which light from the point light source 600 is incident and an exit surface to which light is emitted. In this embodiment, since the point light source 600 is disposed on the side surface of the light guide plate 200, the side surface of the light guide plate 200 becomes an incident surface, and the upper surface becomes an exit surface. On the other hand, the light guide plate 200 is made of a transparent material to minimize the loss of light.

The reflective sheet 300 is disposed under the light guide plate 200 to reflect the light from the light guide plate 200 to the emission surface. That is, the reflective sheet 300 reflects the light leaking to the outside through the lower surface of the light guide plate 200 to the inside of the light guide plate 200 to improve the light utilization efficiency. The reflective sheet 300 is made of a material having high light reflectance.

The optical sheet 230 is disposed on the light guide plate 200 to improve luminance characteristics of light emitted from the light guide plate 200. The optical sheet 230 may include a diffusion sheet for diffusing the light emitted from the light guide plate 200 and a prism sheet for condensing the light emitted from the light guide plate 200 in the front direction.

The accommodation member 300 is coupled to the mold frame 100 to cover the lower portion of the light guide plate 200. The accommodation member 300 includes a bottom portion 310 and a side portion 320 extending from an edge of the bottom portion 310. For example, the accommodating member 300 is made of a metal having superior strength as compared to the mold frame 100.

The liquid crystal display panel 400 is disposed on the light guide plate 200 to display an image. The liquid crystal display panel 400 includes a lower substrate 410, an upper substrate 410 facing the lower substrate 410, a liquid crystal layer (not shown) disposed between the lower substrate 410, and the upper substrate 420. The driving chip 430 is coupled to the substrate 410.

The lower substrate 410 is a transparent glass substrate in which a thin film transistor (TFT), which is a switching element, is formed in a matrix form. Data and gate lines are respectively connected to the source and gate terminals of the TFTs, and a pixel electrode made of a transparent conductive material is connected to the drain terminal.

The upper substrate 420 includes a color filter (not shown) for realizing color and a common electrode (not shown) facing the pixel electrode of the lower substrate 410. The color filter may be formed on the lower substrate 410.

The liquid crystal layer disposed between the lower substrate 410 and the upper substrate 420 is composed of liquid crystal molecules having electrical and optical properties such as anisotropic dielectric constant and anisotropic refractive index. For example, the liquid crystal layer is composed of twisted nematic liquid crystal molecules tilted at a predetermined angle by an electric field formed by the pixel electrode and the common electrode.

The driving chip 430 generates a driving signal for driving the liquid crystal display panel 400 in response to various control signals applied from the outside. The driving chip 430 is electrically connected to the lower substrate 410 through, for example, an anisotropic conductive film (ACF).

When power is applied to the gate terminal of the TFT and the TFT is turned on, an electric field is formed between the pixel electrode and the common electrode. Due to the electric field, the arrangement of liquid crystal molecules of the liquid crystal layer disposed between the lower substrate 410 and the upper substrate 420 is changed, and the transmittance of light is changed according to the arrangement of the liquid crystal molecules to display an image of a desired gray scale. .

The flexible circuit board 500 is connected to one surface of the liquid crystal display panel 400. That is, the flexible circuit board 500 is connected to one side of the lower substrate 410 on which the driving chip 430 is mounted. The flexible circuit board 500 is electrically connected to the lower substrate 410 through, for example, an anisotropic conductive film (ACF).

Although not shown, the flexible circuit board 500 is provided with a device such as a capacitor or a resistor for generating the control signal and stabilizing the control signal.

On the other hand, since the flexible circuit board 500 is flexible, the flexible circuit board 500 is bent from the top surface to the bottom surface of the liquid crystal display panel 400 and fixed. On the contrary, the flexible circuit board 500 may be bent from the top surface of the liquid crystal display panel 400 to the back surface of the accommodation member 300 to be fixed.

The point light source 600 is electrically connected to the flexible circuit board 500 to generate light. For example, the point light source 600 is formed of a light emitting diode (LED) that generates white light. The number of point light sources 600 is determined according to the size of the liquid crystal display panel 400 and the required luminance.

The point light source 600 is disposed on the incident surface side of the light guide plate 200 by bending the flexible circuit board 500. That is, when the flexible circuit board 500 is bent, the point light source 600 is seated on the light source mounting part 110 of the mold frame 100 to be disposed adjacent to the incident surface of the light guide plate 200.

The reflective member 700 is formed on the flexible circuit board 500 corresponding to the area between the point light source 600 and the light guide plate 200. That is, the reflective member 700 is disposed in an area generated by the coupling tolerance between the point light source 600 and the light guide plate 200. Thus, the reflective member 700 reflects the light generated from the point light source 600 to the incident surface of the light guide plate 200.

The reflective member 700 is disposed in parallel with the point light source 600. That is, the reflective member 700 is disposed in the same number of at least one or more point light sources 600 disposed on the flexible circuit board 500. In contrast, the reflective member 700 may be integrally formed to be parallel to the flexible circuit board 500 corresponding to a region between the point light source 600 and the light guide plate 200.

2 is a cross-sectional view illustrating a coupling relationship of a liquid crystal display device taken along line II ′ of FIG. 1, and FIG. 3 is a bottom perspective view illustrating a coupling relationship between a mold frame and a point light source shown in FIG. 1. Is a combined cross sectional view of the liquid crystal display device taken along the line II ′ of FIG. 1.

2 to 4, the mold frame 100 includes a light source mounting part 110 on which a point light source 600 is mounted and fixed on one side thereof. The light source seating unit 110 accommodates and fixes the point light source 600 to prevent the flow departure of the point light source 600 and serves to protect against external impact. For example, the light source seating part 110 is formed as a groove having a predetermined size corresponding to the size of the point light source 600 on one side of the mold frame 100.

The flexible circuit board 500 is connected to one side of the upper surface of the liquid crystal display panel 400. Since the flexible printed circuit board 500 is flexible, the flexible printed circuit board 500 is bent from the top surface to the bottom surface of the liquid crystal display panel 400 and fixed. In this case, the flexible circuit board 500 is fixed to the liquid crystal display panel 400 through the adhesive member 510. For example, the adhesive member 510 is a double-sided tape.

The point light source 600 is electrically connected to the flexible circuit board 500. The point light source 600 is disposed at least one side by side along the one direction of the flexible circuit board 500.

The point light source 600 is disposed on the incident surface side of the light guide plate 200 by bending the flexible circuit board 500. That is, when the flexible circuit board 500 is bent, the point light source 600 is seated on the light source mounting part 110 of the mold frame 100 to be disposed adjacent to the incident surface of the light guide plate 200.

As such, when the point light source 600 is disposed on the incident surface side in a state in which the point light source 600 is attached to the flexible circuit board 500, the point light source 600 is disposed between the point light source 600 and the light guide plate 200 by a coupling tolerance with the light guide plate 200. Space is generated. Therefore, the light generated from the point light source 600 is lost through the flexible circuit board 500 in the region where the space is generated.

The reflective member 700 is formed on the flexible circuit board 500 corresponding to the area between the point light source 600 and the light guide plate 200. That is, the reflective member 700 is disposed in an area generated by the coupling tolerance between the point light source 600 and the light guide plate 200. Thus, the reflective member 700 reflects the light generated from the point light source 600 to the incident surface of the light guide plate 200.

The reflective member 700 is disposed in parallel with the point light source 600. That is, the reflective member 700 is disposed in an area adjacent to the point light source 600 and at least one is formed. Thus, when a plurality of reflecting members 700 are disposed similarly to the point light source 600, the plurality of reflecting members 700 are formed to be spaced apart by a predetermined distance.

The reflective member 700 is coated with white ink. Thus, the reflective member 700 reflects the light emitted from the point light source 600 toward the liquid crystal display panel 400. For example, the reflective member 700 is coated on the flexible circuit board 500 by a silk screen technique. In contrast, the reflective member 700 may be made of a metal material capable of reflecting light.

The reflective member 700 has a predetermined size or more in order to reflect the light emitted from the point light source 600 to the exit angle of the light emitted without loss. That is, the reflective member 700 is preferably larger than the size of the point light source 600 in order to reduce the loss of light generated from the point light source 600.

5 is a cross-sectional view illustrating a liquid crystal display and a path of light according to an embodiment of the present invention.

Referring to FIG. 5, the reflective member 700 is coated with white ink on the flexible circuit board 500 adjacent to the point light source 600. For example, the reflective member 700 is coated on the flexible circuit board 500 by a silk screen method. On the other hand, the reflective member 700 may be made of a metal material that can reflect light.

Since the reflective member 700 is coated with a white ink having a high light reflectance in an area adjacent to the point light source 600, the light emitted from the point light source 600 passes through the translucent flexible circuit board 500 and is lost. prevent. This is because the light emitted from the point light source 600 is supplied to the liquid crystal display panel 400, the light utilization efficiency is improved.

Specifically, among the light emitted from the point light source 600, the first light L1 is emitted to the flexible circuit board 500 in the region generated by the coupling tolerance between the point light source 600 and the light guide plate 200. In this case, the first light L1 is reflected by the reflective member 700 formed on the flexible circuit board 500 and directed to the incident surface of the light guide plate 200. Therefore, the loss of the first light L1 directed to the liquid crystal display panel 400 is reduced, thereby improving light utilization efficiency.

In addition, the second light L2 emitted upward from the light emitted from the point light source 600 is emitted to the accommodation member 300 in a region formed between the point light source 600 and the light guide plate 200. For example, since the accommodating member 300 is made of a metal material having a high reflectance, the second light L2 is reflected by the accommodating member 300 and directed toward the incident surface of the light guide plate 200. Therefore, the loss of the second light L2 directed to the housing member 300 is reduced, thereby improving light utilization efficiency. Alternatively, the accommodation member 300 may include a reflective member having a predetermined pattern for reflecting light, so that the second light L2 may be reflected to the incident surface of the light guide plate 200.

Therefore, in the present embodiment, the light emitted from the point light source 600 and lost is supplied to the incident surface of the light guide plate 200 by the reflective member 700 and the receiving member 300, thereby improving the efficiency of the light.

6 is a cross-sectional view illustrating a liquid crystal display and a path of light according to another embodiment of the present invention. Except for the reflective sheet, the liquid crystal display according to another exemplary embodiment of the present invention has the same configuration as the liquid crystal display according to the exemplary embodiment of the present invention. For the same reference numerals and names are used.

Referring to FIG. 6, the reflective sheet 210 is disposed under the light guide plate 200 to reflect light. In the present exemplary embodiment, the reflective sheet 210 is disposed under the light guide plate 200, and a portion of the reflective sheet 210 extends to an area where the point light source 600 is disposed. That is, the reflective sheet 210 extends corresponding to the space to cover the space generated by the coupling tolerance between the point light source 600 and the light guide plate 200. Therefore, the reflective sheet 210 reflects a part of the light emitted from the point light source 600 to the light guide plate 200.

In detail, the third light L3 emitted upward from the light emitted from the point light source 600 is emitted to the reflective sheet 210 in the region formed between the point light source 600 and the light guide plate 200. Therefore, the third light L3 is reflected by the reflective sheet 210 and directed to the incident surface of the light guide plate 200. Therefore, the loss of the third light L3 emitted from the point light source 600 is reduced, thereby improving light utilization efficiency.

Therefore, in the present embodiment, light emitted from the point light source 600 and lost is supplied to the incident surface of the light guide plate 200 by the reflective member 700 and the reflective sheet 210, thereby improving the efficiency of the light.

FIG. 7 is a cross-sectional view illustrating a liquid crystal display and a light path according to another embodiment of the present invention, and FIG. 8 is a perspective view partially cutaway of the flexible circuit board, the point light source, and the reflective member shown in FIG. 7.

7 and 8, the flexible circuit board 500 includes a signal supply unit 510 for supplying a driving signal to the point light source 600. The signal supply unit 510 is embedded in the flexible circuit board 500 and includes a plurality of wiring units (not shown) and pad units (not shown) made of a conductive material in order to supply driving signals.

A portion of the signal supply unit 510 is formed on the flexible circuit board 500 corresponding to the region where the reflective member 700 is formed. That is, the signal supply unit 510 is embedded in the flexible circuit board 500 so as to cover the reflective member 700 formed in the area adjacent to the point light source 600 as a whole. For example, the signal supply unit 510 is made of metal having high reflectance.

The signal supply unit 510 reflects the light transmitted through the reflective member 700. Specifically, among the light emitted from the point light source 600, the first light (L1) and the fourth light (L4) is a flexible circuit board of the area generated by the coupling tolerance of the point light source 600 and the light guide plate 200 ( 500) exit. In this case, the first light L1 is reflected by the reflective member 700 formed on the flexible circuit board 500 and directed to the incident surface of the light guide plate 200.

Meanwhile, the fourth light L4 passes through the reflective member 700 among the lights directed toward the flexible circuit board 500. The fourth light L4 penetrates through the portion where the reflective member 700 is not coated or the thinly coated portion. In this case, the fourth light L4 is reflected by the signal supply unit 510 made of a metal material. That is, the signal supply unit 510 penetrates the reflective member 700 or reflects the light emitted to the flexible circuit board 500 in the region where the reflective member 700 is not formed, thereby further improving the utilization efficiency of the light. have.

In contrast, the signal supply unit 510 formed in the region corresponding to the reflective member 700 may be formed to be exposed to the flexible circuit board 500. Accordingly, the reflective member 700 may be formed on the signal supply unit 510, or only the signal supply unit 510 may be formed on the flexible circuit board 500 to reflect light.

According to the liquid crystal display device as described above, a reflective member is formed on the flexible circuit board corresponding to a region generated by the coupling tolerance between the point light source and the light guide plate. Therefore, among the light emitted from the point light source, the light directed to the liquid crystal display panel is reflected by the reflective member and directed to the light guide plate. Therefore, the liquid crystal display device can reduce the occurrence of light leakage phenomenon in which a part of the light emitted from the point light source is lost, thereby improving light utilization efficiency.

Furthermore, a signal supply part for supplying a drive signal to the point light source is formed in the flexible circuit board corresponding to the area where the reflection member is formed. Therefore, the signal supply part made of a metal material reflects the light passing through the reflective member to the light guide plate, whereby the utilization efficiency of the light can be further improved.

In the detailed description of the present invention described above with reference to a preferred embodiment of the present invention, those skilled in the art or those skilled in the art having ordinary knowledge in the scope of the 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 scope of the present invention.

Claims (13)

A mold frame having an interior opening; A light guide plate disposed inside the mold frame; An accommodation member coupled to the mold frame to cover a lower portion of the light guide plate; A liquid crystal display panel disposed on the light guide plate to display an image; A flexible circuit board connected to one surface of the liquid crystal display panel and bent from one surface of the liquid crystal display panel to the other surface of the liquid crystal display panel; At least one point light source electrically connected to the flexible circuit board and disposed on an incident surface of the light guide plate to generate light; And And a reflective member formed on a flexible circuit board corresponding to a region between the point light source and the light guide plate and reflecting light generated from the point light source to the incident surface. The liquid crystal display device of claim 1, wherein the reflective member is disposed in parallel with the point light source and is formed at least one. The liquid crystal display device of claim 2, wherein at least one of the reflective members is spaced apart by a predetermined distance. The liquid crystal display of claim 3, wherein the reflective member is coded with white ink. The liquid crystal display device according to claim 4, wherein the reflective member is formed by a silk screen method. The liquid crystal display device according to claim 3, wherein the reflective member is made of a metal material. The flexible circuit board of claim 1, further comprising a signal supply unit for supplying a driving signal to the point light source. And a part of the signal supply part is formed in a region corresponding to the reflective member. The liquid crystal display of claim 7, wherein the signal supply unit is made of a metal material. The liquid crystal display of claim 1, wherein the point light source comprises one or more light emitting diodes. The liquid crystal display of claim 1, wherein the flexible circuit board is fixed to the liquid crystal display panel through an adhesive member. The liquid crystal display device according to claim 10, wherein the adhesive member is a double-sided tape. The liquid crystal display of claim 1, wherein the mold frame includes a light source seating portion on which the point light source is mounted. The optical sheet of claim 1, further comprising: a reflective sheet disposed below the light guide plate to reflect light from the light guide plate to an exit surface, and an optical sheet disposed on top of the light guide plate to diffuse and collect light emitted from the exit surface of the light guide plate. Liquid crystal display device further comprising.

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