KR101830242B1 - Liquid crystal display device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device in which the structure is simplified and manufacturing cost is reduced by removing a PCB on which an LED is mounted.
A feature of the present invention is that a plurality of LEDs are mounted on an FPC connecting a liquid crystal panel and a control PCB, and a light leakage preventing region is further formed in the FPC.
As a result, it is possible to reduce the process cost by eliminating a separate PCB for mounting a plurality of LEDs, and the thickness and weight of the liquid crystal display device can be reduced by the thickness and weight of the conventional PCB in the liquid crystal display device. In addition, it is possible to shorten the process time for modularizing the liquid crystal display device.
In particular, it is possible to prevent the back surface of the light guide plate from being exposed to the outside through the light leakage prevention area, thereby preventing light leakage and light loss from occurring.

Description

[0001] Liquid crystal display device [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device in which the structure is simplified and manufacturing cost is reduced by removing a PCB on which an LED is mounted.

2. Description of the Related Art In recent years, the display field has rapidly developed in line with the information age. In response to this trend, a flat panel display device (FPD) having a thinness, light weight, A plasma display panel (PDP), an electroluminescence display device (ELD), and a field emission display device (FED) : CRT).

Among these, liquid crystal display devices are excellent in moving picture display and are most actively used in the fields of notebook computers, monitors, TVs and the like due to their high contrast ratios.

Such a liquid crystal display device has a liquid crystal panel in which a liquid crystal panel is interposed between two adjacent substrates through a liquid crystal layer as an essential component and changes the alignment direction of the liquid crystal molecules in an electric field in the liquid crystal panel to realize a difference in transmittance do.

However, since the liquid crystal panel does not have its own light emitting element, a separate light source is required to display the difference in transmittance as an image. To this end, a backlight having a light source is disposed on the back surface of the liquid crystal panel.

The liquid crystal panel and the backlight are modularized integrally with the support main through the top cover covering the top edge of the liquid crystal panel and the cover bottom covering the back surface of the backlight in a state where the edge is surrounded by the support main of a square- .

On the other hand, in recent years, such a liquid crystal display device has been widely used as a portable computer, a desktop computer monitor, and a wall-mounted television, and researches to have a massive weight and volume with a large display area It is actively proceeding.

However, in spite of efforts to manufacture a liquid crystal display device of a light weight and a thin thickness, there are too many constituent elements of the liquid crystal display device, and the thinness and light weight of the liquid crystal display device are hindered.

In addition, since the number of components constituting the liquid crystal display device is too large, the process of modularizing them is also complicated and requires a long process time.

In addition, in order to solve the above problems, when the cover bottom is removed, the light guide plate of the backlight is exposed to the outside, causing light leakage and light loss.

SUMMARY OF THE INVENTION It is a first object of the present invention to provide a lightweight and thin liquid crystal display device for solving the above-mentioned problems, and a second object is to improve the efficiency of the process.

A third object of the present invention is to prevent light leakage and light loss from being caused by the light guide plate exposed to the outside.

In order to achieve the above-mentioned object, the present invention provides a liquid crystal display comprising: a reflection plate; A light guide plate disposed on the reflection plate; An optical sheet that is seated on the light guide plate; A liquid crystal panel comprising a first substrate and a second substrate which are seated on the optical sheet and are bonded to each other with a liquid crystal layer interposed therebetween; A flexible printed circuit (FPC) connected to one side of the first substrate and folded to cover the back surface of the reflection plate and having a plurality of LEDs facing the light incident side of the light guide plate, the LEDs being spaced apart from each other; A light guide plate, the optical sheet, and a support main body which surrounds the edge of the liquid crystal panel.

Here, the FPC includes first and second layers, the first layer is located outside, and a driving element for applying a signal to the liquid crystal panel is mounted. The second layer is located inside, And the back surface of the reflection plate is covered with the light leakage preventing region where the first layer extends.

The first layer is opaque, and the FPC is attached to the back surface of the support main body through the adhesive material.

In addition, the first and second layers each include a base film, a metal wiring, and a cover layer, and the base film of the first layer is made of an opaque material.

As described above, according to the present invention, a plurality of LEDs are mounted on an FPC connecting a liquid crystal panel and a control PCB, and a light leakage preventing region is further formed in the FPC, whereby a separate It is possible to reduce the process cost by eliminating the PCB, and it is possible to bring the thickness and weight of the liquid crystal display device to the thickness and weight of the conventional PCB in the liquid crystal display device. Further, there is an effect that the time required for modularizing the liquid crystal display device can be shortened.

In particular, it is possible to prevent the back surface of the light guide plate from being exposed to the outside through the light leakage prevention area, thereby preventing light leakage and light loss from occurring.

1 is an exploded perspective view of a liquid crystal display device according to an embodiment of the present invention;
2 is a rear perspective view schematically showing an FPC according to an embodiment of the present invention.
3 is a cross-sectional view schematically showing the modularized liquid crystal display of FIG. 1;

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

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

The liquid crystal display device includes a liquid crystal panel 110 and a backlight unit 120 and includes a support main 130 for modularizing the liquid crystal panel 110 and the backlight unit 120.

The liquid crystal panel 110 is a part that plays a key role in image display and includes a first substrate 112 and a second substrate 112 which are bonded to each other with a liquid crystal layer (not shown) therebetween, (114).

Although not shown in the drawing, a plurality of gate lines and data lines cross each other on the inner surface of a first substrate 112 called a lower substrate or an array substrate, pixels are defined, and thin- and a thin film transistor (TFT), which are connected in a one-to-one correspondence with the transparent pixel electrodes formed in the respective pixels.

On the inner surface of the second substrate 114 called an upper substrate or a color filter substrate, color filters of red (R), green (G), and blue (B) And a black matrix for covering the gate lines, the data lines, and the thin film transistors. In addition, color filters of red (R), green (G), and blue (B) colors and transparent common electrodes covering the black matrix are provided.

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

At this time, the first substrate 112 is further provided with a pad region as compared with the second substrate 114, so that the area of one edge is larger. Therefore, a drive circuit 115 for applying a signal to a plurality of gate lines and data lines is formed as a pad region at one edge of the first substrate 112.

This structure is called a COG (chip on glass) type liquid crystal panel 110. In the COG method, an anisotropic conductive film (not shown) is used to directly drive the driving circuit 115 on the first substrate 112 It has an advantage that the proportion of the liquid crystal panel 110 occupied by the liquid crystal display device can be increased.

The driving circuit 115 is connected to a plurality of gates and a data driving circuit, and each gate and data driving circuit 115 is connected to a gate and a data line (not shown) on the first substrate 112, respectively.

The gate and data driving circuit 115 is connected to the FPC 140 which outputs various signal voltages.

A plurality of wiring patterns (not shown) connected to the data and gate driving circuit 115 are aligned to one side edge of the FPC 140 and bonded to the liquid crystal panel 110 via an anisotropic conductive film (not shown) .

A plurality of LEDs 129 are mounted on the back surface of the FPC 140 according to the present invention with a predetermined distance therebetween. The FPC 140 is folded back to the back surface of the backlight unit 120 during the modularization process of the liquid crystal display, A plurality of LEDs 129 mounted on the FPC 140 face the light incidence surface 123a of the light guide plate 123 of the backlight unit 120 located on the back surface of the liquid crystal panel 110. [ Let me take a closer look at this later.

When the thin film transistor selected for each gate line is turned on by the on / off signal of the gate driving circuit, the liquid crystal panel 110 transmits the signal voltage of the data driving circuit to the corresponding pixel electrode through the data line. The arrangement direction of the liquid crystal molecules is changed by the electric field between the pixel electrode and the common electrode to show a difference in transmittance.

In the liquid crystal display device according to the present invention, a backlight unit 120 for supplying light to the back surface of the liquid crystal panel 110 is provided so that the difference in transmittance of the liquid crystal panel 110 is manifested to the outside.

The backlight unit 120 includes a plurality of LEDs 129 mounted on the FPC 140, a white or silver reflective plate 125, a light guide plate 123 seated on the reflective plate 125, And an optical sheet 121 which is made of glass.

As described above, the plurality of LEDs 129 are mounted on the FPC 140, which is folded back and bonded to the back surface of the backlight unit 120. At this time, the FPC 140 includes a plurality of LEDs 129, (123a) of the light guide plate (123).

Accordingly, the plurality of LEDs 129 are positioned on one side of the light guide plate 123 so as to face the light incident surface 123a of the light guide plate 123. [

A plurality of LEDs 129 are mounted on the FPC 140 so that the FPC 140 is bent and attached to the back surface of the backlight unit 120 so that a separate PCB (Not shown).

Accordingly, the process cost can be reduced by eliminating the PCB (not shown), and the thickness and weight of the liquid crystal display device can be reduced by the thickness and weight of the conventional PCB (not shown) in the liquid crystal display device.

In particular, the FPC 140 of the present invention is characterized by further comprising a light leakage and light loss prevention area 143 (hereinafter referred to as a light leakage prevention area).

That is, the liquid crystal display of the present invention is formed so as to cover a part of the back surface of the reflection plate 125 through the light-saving area 143 of the FPC 140 that is folded back and bonded to the back surface of the backlight unit 120.

Accordingly, the light guide plate 123 can be prevented from being exposed to the outside, and light leakage and light loss can be prevented from being caused by the light guide plate 123 exposed to the outside. Let me take a closer look at this later.

At this time, the plurality of LEDs 129 emit white light toward the light incoming surface 123a of the light guide plate 123, including LED chips (not shown) that emit all the RGB colors or emit white light. The plurality of LEDs 129 emit light having colors of red (R), green (G), and blue (B), respectively. The plurality of RGB LEDs 129 are turned on at once to emit white light It can also be implemented.

The light guide plate 123 on which the light emitted from the plurality of LEDs 129a is incident is formed so that the light incident from the LED 129 travels in the light guide plate 123 by total reflection several times and spreads evenly over a wide area of the light guide plate 123 And provides a surface light source to the liquid crystal panel 110.

The thickness of the backlight unit 120 and the overall thickness of the liquid crystal display device can be reduced by forming the light guide plate 123 such that the thickness of the other portions of the light guide plate 123 except for the light incident portion is thinner than that of the light-

For this purpose, the light guide plate 123 may include an inclined surface on an upper surface through which light incident from the LED 129 is emitted.

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

Here, the pattern may be formed in various shapes such as an elliptical pattern, a polygon pattern, a hologram pattern, and the like in order to guide light incident into the light guide plate 123. The pattern is formed on the lower surface of the light guide plate 123 by a printing method or an injection method.

The reflection plate 125 is attached to the back surface of the light guide plate 123 and reflects light passing through the back surface of the light guide plate 123 toward the liquid crystal panel 110 to improve the brightness of light.

At this time, the FPC 140 of the present invention is bent to the back surface of the backlight unit 120 and covers a part of the back surface of the reflection plate 125 on the light-incoming unit side.

The reflection plate 125 can be prevented from sagging through the FPC 140 and the gap between the reflection plate 125 and the light guide plate 123 can prevent the light guide plate 123 from being reflected by the reflection plate 125 It is possible to prevent light leakage and light loss from occurring through the region.

The optical sheet 121 on the light guide plate 123 includes a diffusion sheet, at least one light condensing sheet, and the like.

Here, the diffusion sheet is positioned directly above the light guide plate 123, and serves to adjust the direction of light so that the light travels toward the light condensing sheet while dispersing the light incident through the light guide plate 123.

The light diffused through the diffusion sheet by the light condensing sheet is condensed in the direction of the liquid crystal panel 110. Therefore, the light passing through the light condensing sheet is almost perpendicular to the liquid crystal panel 110.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the support main 130. The support main 130 has a rectangular frame shape to define the edges of the liquid crystal panel 110 and the backlight unit 120 do.

At this time, the support main body 130 is composed of the vertical part 131 covering the edges of the liquid crystal panel 110 and the backlight unit 120, and the liquid crystal panel 110 and the backlight unit The liquid crystal panel 110 is mounted on the protrusion 133 through an adhesive material such as a double-sided tape.

The FPC 140 and the support main body 130 are disposed on the back surface of the backlight unit 120 in a process in which the FPC 140 attached to the pad region of the first substrate 112 of the liquid crystal panel 110 is bent and adhered to the back surface of the backlight unit 120, They are attached to each other through an adhesive material such as double-sided tape.

The liquid crystal display according to the embodiment of the present invention has a structure in which a top cover (not shown) and a cover bottom are removed, and a lightweight and thin type liquid crystal display And it is possible to simplify the process.

In addition, the elimination of the top cover (not shown) and the cover bottom (not shown) made of a metal material can reduce the process cost.

Here, the support main 130 may be referred to as a guide panel, a main support, or a mold frame.

2 is a rear perspective view schematically showing an FPC according to an embodiment of the present invention.

As shown in the drawing, a plurality of LEDs 129 are mounted on the FPC 140 by a surface mount technology (SMT) at a predetermined interval, and on the opposite side where a plurality of LEDs 129 are mounted, (Not shown) for transferring a signal to the gate and data driving circuit (115 in FIG. 1) formed in the pad region of the first substrate (112 in FIG. 1) of the liquid crystal panel (110 in FIG. 1) Various signals are applied to the liquid crystal panel (110 in FIG. 1) through the driving element (not shown) and the wiring (not shown) formed in the FPC 140.

The FPC 140 is mounted with an LED driving circuit (not shown) connected to an external driving circuit (not shown) to operate the LED 129 according to an input signal.

The FPC 140 includes a first layer 141a and a second layer 141b. The first layer 141a is a region where a driving element (not shown) is mounted, and a base film (not shown) And a plurality of metal wires (not shown) formed by patterning a conductive material for applying a signal to a driving element (not shown).

At this time, it is preferable that the base film (not shown) of the first layer 141a is formed to have opaque hue.

The second layer 141b is a region where a plurality of LEDs 129 are mounted and a signal is transmitted by a plurality of LEDs 129 on the second layer 141b and on the base film (not shown) and the base film And a plurality of metal wires (not shown) for application.

Here, each base film (not shown) serves to mount and support a plurality of metal wirings (not shown), driving elements (not shown), and a plurality of LEDs 129 in an upper layer thereof.

A cover layer (not shown) is formed as an organic or inorganic insulating material for protecting a plurality of metal interconnects (not shown) on a plurality of metal interconnects (not shown) of the respective layers 141a and 141b.

The FPC 140 is connected to a control PCB (not shown) separately provided on the back surface of the LCD through a connector (not shown) through a flexible cable 145 (see FIG. 1) A control signal from a control PCB (not shown) is applied to a driving element (not shown) and an LED driving circuit (not shown) mounted on the FPC 140.

The FPC 140 is folded and closely contacted with the back surface of the backlight unit 120 in FIG. 1 so that the LED 129 mounted on the FPC 140 contacts the light incoming surface 123a of the light guide plate 123 in FIG. .

Thus, the present invention can reduce the process cost and can bring about the thinness and light weight of the liquid crystal display device.

That is, the conventional liquid crystal display device is required to separately include a PCB (not shown) for mounting the LED 129 in order to place a plurality of LEDs 129 on one side of the light guide plate 123 1, the LED 129 is mounted on the FPC 140 attached to the pad region of the first substrate (112 in FIG. 1) of the liquid crystal panel (110 in FIG. 1), and the FPC 140 is mounted on the backlight unit (120 in Fig. 1).

Therefore, an expensive PCB (not shown) for mounting the LED 129 is not needed, which can reduce the manufacturing cost and simplify the structure. In addition, by removing the PCB (not shown), the thickness and weight of the liquid crystal display device can be reduced by the thickness and weight of the conventional PCB (not shown).

At this time, when the FPC 140 is bent to the back surface of the backlight unit (120 in FIG. 1) and brought into close contact with the FPC 140, the second layer 141b on which the LED 129 is mounted is positioned inside, It is preferable that the LED 129 mounted on the second layer 141b of the light guide plate 140 faces the light incidence surface (123a in Fig. 1) of the light guide plate (123 in Fig. 1).

By electrically connecting the control PCB (not shown) and the driving device (not shown) provided on the rear surface of the liquid crystal display device with the first layer 141a on which the driving device (not shown) is mounted, So that it is more easily connected.

When the LED 129 is mounted on the FPC 140 attached to the liquid crystal panel 110 in FIG. 1, when the liquid crystal display device is assembled, the FPC 140 is mounted on the backlight unit 120 The FPC 140 of the present invention further includes a light leakage preventing region 143 to cover a part of the back surface of the reflection plate 125 of FIG. 1 through the light reflection preventing region 143 Respectively.

The light leakage preventing region 143 of the FPC 140 may be formed of any one of the first and second layers 141a and 141b of the FPC 140 to prevent the thickness of the liquid crystal display device from being increased The first layer 141a on which the driving element (not shown) located on the outer side of the FPC 140 is extended is formed so as to extend to the backside of the liquid crystal display device, It is desirable to prevent the occurrence of a step due to the light-blocking area 143 of the light-

In particular, since the base film (not shown) of the first layer 141a has an opaque hue, the light leakage preventing effect can be further improved.

At this time, the light-shielding region 143 may be formed by extending only a base film (not shown) of the first layer 141a.

Accordingly, the light guide plate 123 of FIG. 1 can be prevented from being exposed to the outside, and light leakage and light loss can be prevented by the light guide plate 123 of FIG. 1 exposed to the outside. This will be described in more detail with reference to FIG.

3 is a cross-sectional view schematically showing the modularized liquid crystal display of FIG.

As shown in the drawing, a liquid crystal panel 110 in which a liquid crystal layer (not shown) is interposed between the first and second substrates 112 and 114 and the first and second substrates 112 and 114 And polarizing plates 119a and 119b for selectively transmitting only specific light are attached to the outer surface.

At this time, the second substrate 114 is smaller than the first substrate 112 to partially expose the first edge of the first substrate 112, and a COG A gate and a data driving circuit 115 are mounted.

The gate and data driving circuit 115 outputs various signal voltages and is electrically connected to the FPC 140 having the plurality of LEDs 129 mounted thereon.

A reflection plate 125 attached to the lower portion of the optical sheet 121, the light guide plate 123 and the light guide plate 123 and a plurality of LEDs 129 mounted on the FPC 140 are disposed on the back surface of the liquid crystal panel 110 The backlight unit 120 is located.

The plurality of LEDs 129 mounted on the FPC 140 are connected to the vertical portion 131 of the support main body 130 and the light guide plate 123) of the light guide plate (123).

Accordingly, the plurality of LEDs 129 emit light toward the light-incident portion L1 of the light guide plate 123. [

At this time, the light guide plate 123 is formed in a flat shape having a predetermined thickness, and an inclined surface is formed on the upper surface, and the thickness d1 of the light-incident portion L1 facing the plurality of LEDs 129 is different from the thickness (D2) of the second electrode layer (L2).

The thickness d2 of the display portion L2 of the light guide plate 123 is set to be smaller than the thickness d2 of the light guide plate 123. The thickness d2 of the light guide plate 123 is set so that the lower surface of the light guide plate 123 and the upper surface corresponding to the lower surface thereof are inclined at the light- Is thinner than the thickness (d1) of the first electrode (L1).

The light emitted from the LED 129 is incident on the light guide plate 123 through the light incident portion L1 of the light guide plate 123 and the thickness d2 of the display portion L2 of the light guide plate 123, Can be formed thin.

The overall thickness of the backlight unit 120 including the light guide plate 123 and the optical sheet 121 can be formed so as not to exceed the thickness d2 of the light entering portion L2 of the light guide plate 123. [

The liquid crystal panel 110 and the backlight unit 120 are modularized by the support main 130. The support main 130 includes a backlight unit 120 and a vertical part 131 that surrounds the edges of the liquid crystal panel 110 And a protrusion 133 is provided on the inner side of the vertical part 131 so that the liquid crystal panel 110 is supported on the protrusion 133. At this time, the liquid crystal panel 110 is attached to the protrusion 133 of the support main body 130 through an adhesive material 150 such as a double-sided tape.

The inner part of the second layer 141b of the FPC 140 is bent in the vertical direction of the support main body 130 in the process of bending the FPC 140 connected to the liquid crystal panel 110 to the back surface of the backlight unit 120. [ Through the adhesive material 150 such as a double-sided tape and the back side of the part 131. [

The FPC 140 is formed so that the light-preventing area 143 extending from the first layer 141a covers a part of the back surface of the reflection plate 125. [

Therefore, the back surface of the light guide plate 123 can be prevented from being exposed to the outside, and light leakage and light loss can be prevented from being caused by the light guide plate 123 exposed to the outside.

The reflection plate 125 may be formed to have a smaller size than the light guide plate 123 or may be formed of a reflective plate 125 and a reflection plate 125 due to a process error during the process of attaching the reflection plate 125 to the back surface of the light guide plate 123. [ A gap is formed between the light guide plate 123 and a portion of the rear surface of the light guide plate 123 on the side of the light entrance portion L1 is exposed through the gap.

A light leakage of light incident into the light guide plate 123 is generated through a part of the rear surface of the exposed light guide plate 123, thereby causing optical loss.

Particularly, in the structure in which the cover bottom (not shown) surrounding the back surface of the backlight unit 120 is removed as in the present invention, the problem caused by the light leakage and the light loss becomes more significant.

Therefore, according to the present invention, the light-shielding region 143 is further formed in the FPC 140, and the light-shielding region 143 surrounds a part of the back surface of the reflection plate 125, It is possible to prevent exposure to light and to prevent occurrence of light leakage and light loss.

By supporting the back surface of the reflection plate 125 through the light leakage preventing region 143 of the FPC 140, it is possible to prevent the reflection plate 125 from being sagged.

As described above, the liquid crystal display of the present invention is configured such that a plurality of LEDs 129 are mounted on the FPC 140 connecting the liquid crystal panel 110 and the control PCB (not shown) It is possible to reduce the process cost by eliminating a separate PCB (not shown) for mounting the liquid crystal display device, and it is possible to reduce the thickness and weight of the liquid crystal display device by the thickness and weight occupied by the conventional PCB (not shown) have. In addition, it is possible to shorten the process time for modularizing the liquid crystal display device.

The back surface of the light guide plate 123 is formed through the light leakage prevention area 143 of the FPC 140 bent and attached to the back surface of the backlight unit 120 It is possible to prevent exposure to the outside, thereby preventing light leakage and light loss from occurring.

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

110: liquid crystal panel (112, 114: first and second substrates), 119a, 119b:
115: driving circuit, 120: backlight unit
121: optical sheet, 123: light guide plate (123a: light incoming surface), 125:
129: LED, 130: support main (131: vertical part, 133: protruding part)
140: FPCs 141a and 141b (first and second layers, 143: light blocking area)
150: Adhesive material

Claims (6)

A light guide plate positioned on the reflection plate;
An optical sheet that is seated on the light guide plate;
A liquid crystal panel comprising a first substrate and a second substrate which are seated on the optical sheet and are bonded to each other with a liquid crystal layer interposed therebetween;
A flexible printed circuit (FPC) connected to one side of the first substrate and folded to cover the back surface of the reflection plate and having a plurality of LEDs facing the light incident side of the light guide plate, the LEDs being spaced apart from each other;
The light guide plate, the optical sheet, and the support main body including the edges of the liquid crystal panel
/ RTI >
The FPC includes first and second layers, and the opaque first layer located outside is extended from the second layer to provide a light-preventing area,
The light emitting device of claim 1, wherein the second layer is located on the same plane as the second layer and the end of the second layer faces the end of the light reflecting plate, And covers a part of the back surface of the reflection plate.
The method according to claim 1,
A driving element for applying a signal to the liquid crystal panel is mounted on the first layer, and a plurality of LEDs are mounted on the second layer.
delete delete The method according to claim 1,
Wherein the FPC is attached to the back surface of the support main body through an adhesive material.
The method according to claim 1,
Wherein the first and second layers include a base film, a metal wiring, and a cover layer, respectively, and the base film of the first layer is made of an opaque material.

Images