KR101830725B1 - Liquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device, and more particularly, to a lightweight and thin liquid crystal display device using an LED as a light source.
A feature of the present invention is that a lengthwise longitudinal edge of the PCB of the LED assembly is formed in a concavo-convex shape composed of concave and convex portions, and a horizontal surface corresponding to one edge of the cover bottom where the LED assembly is located And a hole formed at one edge of the PCB is inserted into the hole.
Accordingly, a lightweight and thin liquid crystal display device is provided.
In addition, in the process of attaching the LED assembly, the efficiency of the process can be improved and the fixing force of the LED assembly can be improved. Therefore, it is possible to prevent the LED assembly from being distorted, and it is possible to prevent the optical loss of the LED assembly from being generated.
Also, the material cost can be reduced by the recess of the PCB.

Description

[0001] Liquid crystal display device [0002]

The present invention relates to a liquid crystal display device, and more particularly, to a lightweight and thin liquid crystal display device using an LED as a light source.

A liquid crystal display device (LCD), which is advantageous for moving picture display and has a large contrast ratio and is actively used in TVs and monitors, exhibits optical anisotropy and polarization properties of a liquid crystal, And the like.

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.

Here, as a light source of the backlight unit, a cold cathode fluorescent lamp (CCFL), an external electrode fluorescent lamp, a light emitting diode (LED) .

In particular, LEDs are widely used as light sources for displays, having characteristics such as small size, low power consumption, and high reliability.

1 is a cross-sectional view of a liquid crystal display device using a general LED as a light source.

As shown, a typical liquid crystal display device includes a liquid crystal panel 10, a backlight unit 20, a support main 30, a cover bottom 50, and a top cover 40.

The liquid crystal panel 10 is constituted by first and second substrates 12 and 14 which are in contact with each other with a liquid crystal layer interposed therebetween, which plays a key role in image display.

A backlight unit 20 is provided behind the liquid crystal panel 10.

The backlight unit 20 includes an LED assembly 29 arranged along the longitudinal direction of at least one side edge of the support main body 30, a white or silver reflective plate 25 seated on the cover bottom 50, 25, and a plurality of optical sheets 21 interposed therebetween.

The LED assembly 29 is formed on one side of the light guide plate 23 and includes a plurality of LEDs 29a emitting white light and an LED PCB 29b mounted on the LEDs 29a ).

The liquid crystal panel 10 and the backlight unit 20 are covered with a top cover 40 covering the upper edge of the liquid crystal panel 10 in a state where the edge is surrounded by the support main 30 having a rectangular frame shape, And the cover bottoms 50 are integrally joined to each other through the support main body 30.

And reference numerals 19a and 19b denote polarizing plates attached to the front and back surfaces of the liquid crystal panel 10 to control the polarization direction of light, respectively.

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, it is difficult to reduce the volume and weight of the backlight unit 20, which has the greatest influence on the overall weight of the liquid crystal display device, despite the efforts to make the liquid crystal display device lightweight and thin. It is a fact that it is hindering light weight.

Particularly, the LED assembly 29 is attached and fixed to the cover bottom 50 through a double-sided tape (not shown), but the fixing force of the LED assembly 29 is weak only by a double-sided tape (not shown).

Since the process of attaching the LED assembly 29 is manually performed by the operator, the mounting and alignment of the LED assembly 29 is not easy and the LED assembly 29 is distorted.

All of the light emitted from the LED 29a is not incident into the light guide plate 23 due to the deformation of the LED assembly 29 so that the light loss of the LED 29a is caused, .

In addition, the reliability of the product is deteriorated, and the defective rate is large, resulting in a problem of remarkably lowering workability and productivity.

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 problems.

A second object of the present invention is to provide a liquid crystal display device of high brightness by minimizing the light loss of the LED.

The third object is to increase the productivity, to improve the reliability of the product by uniformly and stably bonding the adhesive, and to reduce the material cost.

In order to achieve the above-mentioned object, the present invention provides a liquid crystal display comprising: a reflection plate; A light guide plate mounted on the reflection plate; An LED assembly including a plurality of LEDs arranged along the light incidence plane of the light guide plate, and a PCB having the plurality of LEDs mounted thereon, the PCB including a concave portion and a convex portion at one edge in the longitudinal direction; A liquid crystal panel mounted on the light guide plate; A horizontal bottom surface in contact with the reflection plate and a cover bottom in a side surface perpendicular to the horizontal surface, wherein the horizontal surface is provided with holes through which the convex portions are inserted.

In this case, the PCB has a long bar shape, and the PCB has a first width corresponding to the convex portion and a second width corresponding to the concave portion perpendicularly to the longitudinal direction, It is located in the convex part.

A portion of the convex portion that is inserted into the hole is equal to or smaller than a thickness of the cover bottom portion.

The LED assembly is attached to the side surface through an adhesive material such as a double-sided tape. The PCB may be a metal printed circuit board (MCPCB), a flame resistant 4 (FR-4) It consists of the selected one.

The liquid crystal display device may further include a support main body including an optical sheet between the light guide plate and the liquid crystal panel and covering an edge of the liquid crystal panel. The cover main body and the cover bottom are coupled to each other. And a top cover.

As described above, according to the present invention, the longitudinal edge of the PCB of the LED assembly is formed in a concavo-convex shape including a concave portion and a convex portion, A lightweight and thin liquid crystal display device can be provided by forming a hole into which a convex portion formed at one edge of the PCB can be inserted in a horizontal plane corresponding to an edge.

In addition, in the process of attaching the LED assembly, the efficiency of the process can be improved, and the fixation force of the LED assembly can be improved, thereby preventing the LED assembly from being distorted.

Thereby, there is an effect that the light loss of the LED assembly can be prevented.

In addition, there is an effect that the material cost can be reduced by the recess of the PCB.

1 is a sectional view of a liquid crystal display device using a general LED as a light source.
2 is an exploded perspective view schematically illustrating a liquid crystal display device according to an embodiment of the present invention.
3 is a perspective view schematically illustrating an LED assembly according to an embodiment of the present invention.
FIGS. 4A and 4B are perspective views schematically showing attachment and fixing of the LED assembly according to the embodiment of the present invention; FIGS.
5 is a plan view schematically showing the formation of the PCB base of the PCB of the present invention.

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

2 is an exploded perspective view schematically showing 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 body 130 and a cover bottom 150 for modularizing the liquid crystal panel 110 and the backlight unit 120, And a top cover 140.

Here, 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 114 which are bonded to each other with a liquid crystal layer interposed therebetween.

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, which is generally referred to as an array substrate, to define pixels, and a thin film transistor transistor: TFT) are connected in one-to-one correspondence with the transparent pixel electrodes formed in each pixel.

On the inner surface of the second substrate 114 called a color filter substrate, color filters of red (R), green (G) and blue (B) colors corresponding to the respective pixels and color filters of red A black matrix for covering gate lines, data lines, and thin film transistors is provided. 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.

A printed circuit board 117 is connected to at least one edge of the liquid crystal panel 110 via a connection member 116 such as a flexible circuit board or a tape carrier package (TCP) The support main body 130 or the cover bottom 150 is properly bent.

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.

And a backlight unit 120 for supplying light to the back surface of the liquid crystal panel 110 so that the difference in transmittance of the liquid crystal panel 110 is externally expressed.

The backlight unit 120 includes an LED assembly 200, a white or silver reflective plate 125, a light guide plate 123 seated on the reflective plate 125, and an optical sheet 121 interposed therebetween .

The LED assembly 200 is disposed on one side of the light guide plate 123 so as to face the light incident surface of the light guide plate 123 and includes a plurality of LEDs 210 and a plurality of PCBs 220 ).

In this case, the LED assembly 200 of the present invention is characterized in that a plurality of grooves 221 are formed at a predetermined distance in the longitudinal direction of the PCB 220.

That is, one longitudinal edge of the PCB 220 facing the cover bottom 150 is divided into a plurality of recesses 221 (concave and convex portions), which are composed of concave portions 221 and convex portions 223, ).

 As a result, the PCB 220 corresponding to the concave portion 221 of the LED assembly 200 is removed, so that the liquid crystal display device 200 displays a liquid crystal display The light weight of the apparatus can be obtained.

In addition, the material cost can be reduced. Let me take a closer look at this later.

The light guiding plate 123 through which the light emitted from the plurality of LEDs 210 of the LED assembly 200 is incident is formed such that the light incident from the LED 210 passes through the light guiding plate 123, ) To provide a surface light source to the liquid crystal panel 110. [

The light guide plate 123 may include a pattern of a specific pattern 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 disposed on 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.

The optical sheet 121 on the light guide plate 123 includes a diffusion sheet and at least one light condensing sheet and diffuses or condenses the light passing through the light guide plate 123 to provide a more uniform surface light source to the liquid crystal panel 110 Let it enter.

The liquid crystal panel 110 and the backlight unit 120 are modularized through a top cover 140, a support main 130 and a cover bottom 150. The top cover 140 is disposed on the upper surface and the side surface of the liquid crystal panel 110, The top cover 140 is opened so that an image formed on the liquid crystal panel 110 is displayed.

The cover bottom 150 on which the liquid crystal panel 110 and the backlight unit 120 are mounted and which is the basis for assembling the entire apparatus of the liquid crystal display apparatus 100 includes a horizontal surface 151 closely contacting the back surface of the backlight unit 120, And a side surface 153 whose edge is vertically bent upward.

At this time, the convex portion 223 formed on one edge of the LED assembly 200 in the longitudinal direction of the PCB 220 may be inserted into the cover bottom 150 on the horizontal surface 151 at the edge where the LED assembly 200 is located Hole 155 is formed.

The holes 155 formed in the horizontal surface 151 of the cover bottom 150 improve the fixing force of the LED assembly 200 and align the position of the LED assembly 200.

Accordingly, the efficiency of the process is improved in the process of attaching the LED assembly 200 to the side surface 153 of the cover bottom 150. As a result, it is possible to prevent the LED assembly 200 from being distorted, to prevent the light loss of the LED 210 from being generated, and to provide a high-brightness liquid crystal display device.

In addition, the width of the PCB 220, which is vertically erected to form the thickness of the liquid crystal display device, is reduced to bring the thickness of the liquid crystal display device to the width of the PCB 220 inserted into the horizontal surface 151 of the cover bottom 150 do. Let me take a closer look at this later.

The support main body 130 having a rectangular frame shape and resting on the cover bottom 150 and covering the edges of the liquid crystal panel 110 and the backlight unit 120 includes a top cover 140, a cover bottom 150, .

The cover main body 130 may be referred to as a guide panel or a main support or a mold frame. The cover main body 130 may be referred to as a bottom cover or a bottom cover, I will.

At this time, the backlight unit 120 of the above-described structure is generally called a side light type, and a plurality of LEDs 210 may be arranged in a plurality of layers on the PCB 220 according to purposes. Further, it is also possible to provide a plurality of LED assemblies 200 each in a corresponding manner so as to interpose the cover bottoms 150 along opposite side edge portions facing each other.

The above-described liquid crystal display device has a structure in which the longitudinal edge of the PCB 220 of the LED assembly 200 is formed into a concavo-convex shape including a concave portion 221 and a convex portion 223 A hole 155 is formed in the horizontal surface 151 corresponding to one edge of the cover bottom 150 where the LED assembly 200 is positioned so that the convex portion 223 formed at one edge of the PCB 220 can be inserted and inserted into the horizontal surface 151 Thereby providing a lightweight and thin liquid crystal display device.

In addition, in the process of attaching the LED assembly 200, the efficiency of the process can be improved, and the fixing force of the LED assembly 200 can be improved. Therefore, it is possible to prevent the LED assembly 200 from being distorted, and to prevent the optical loss of the LED assembly 200 from being generated.

In addition, the recess 221 of the PCB 220 can reduce the material cost.

3 is a perspective view schematically showing an LED assembly according to an embodiment of the present invention.

As shown in the figure, the LED assembly 200 includes a plurality of LEDs 210 and a PCB 220 having a plurality of LEDs 210 spaced apart from each other by a surface mount technology (SMT) do.

That is, the PCB 220 has a long bar shape, and the plurality of LEDs 210 are mounted at a predetermined distance along the longitudinal direction of the PCB 220.

At this time, the plurality of LEDs 210 are connected in parallel to each other through a power supply line (not shown) formed on the PCB 220. At this time, the plurality of LEDs 210 emit red (G), and blue (B), and the plurality of RGB LEDs 210 are turned on at once to realize white light by color mixing.

On the other hand, using the LED 210 configured with an LED chip (not shown) that emits all the colors of RGB, the white light may be realized by each of the LEDs 210, or a complete white color including a white- Emitting LED 210 may be used.

The PCB 220 includes a PCB base 225, an insulating layer 227 and a power wiring layer 229. The PCB base 225 includes a power wiring layer 229 and an insulating layer 227 and other components And is mounted on the upper layer to support the heat generated from the plurality of LEDs 210 toward the bottom surface.

The PCB base 225 may be a metal printed circuit board (MCPCB) or a flame resistant 4 (FR-4) formed of a metal having a high thermal conductivity such as aluminum (Al) Based substrate, and the heat transfer function can be improved by applying the heat transfer material.

That is, the LED 210 is a light emitting device, and the temperature is rapidly increased according to the use time. Such a temperature rise is characterized by a lifetime and a luminance change of the LED 210. Therefore, one of the most important matters when the LED 210 is used as the light source of the backlight unit 120 (FIG. 2) is the heat radiation design according to the temperature rise of the LED 210.

The PCB base 225 constituting the PCB 220 on which the plurality of LEDs 210 are mounted is formed of a metal having a high thermal conductivity so that the LED backlight unit 120 of FIG. The heat of the high temperature can be effectively released to the outside of the liquid crystal display device.

A power wiring layer 229 is formed on the PCB base 225. The power wiring layer 229 is formed of a plurality of metal wiring patterns (not shown) formed by patterning a conductive material on the PCB base 225. Between the PCB base 225 and the power wiring layer 229, The insulating layer 227 is positioned to electrically isolate the PCB base 225 from the power wiring layer 229.

A plurality of metal wires (not shown) serve to transmit an on / off signal of the plurality of LEDs 210 mounted on the PCB 220. At this time, a plurality of metal wires (not shown) Are formed so as not to overlap each other.

A cover layer (not shown) may be formed on the power wiring layer 229 as an organic or inorganic insulating material for protecting the power wiring layer 229 except for a portion where a plurality of metal wirings (not shown) are formed .

The cover layer (not shown) is made of a white material capable of reflecting light, and may include reflection function as well as insulation function.

A plurality of grooves 221 spaced apart from each other by a predetermined distance are formed at one longitudinal edge of the PCB 220. One edge of the PCB 220 is recessed by recesses 221 and protrusions 221, 223).

Here, recesses 221 are formed in an area between the LEDs 210 mounted on the PCB 220.

That is, the PCB 220 has a first width h1 corresponding to the convex portion 223 and a second width h2 corresponding to the concave portion perpendicularly to the longitudinal direction, .

At this time, a plurality of LEDs 210 are mounted on the region of the PCB 220 having the first width h1.

The second width h2 of the PCB 220 may be 1/3 to 1/2 of the first width h1 so as not to affect the rigidity of the PCB 220 itself.

As a result, the PCB 220 corresponding to the concave portion 221 of the LED assembly 200 is removed, so that the liquid crystal display device 200 displays a liquid crystal display The light weight of the apparatus can be obtained.

In particular, in order to design the heat dissipation of the LED 210 by the PCB 220, the weight of the liquid crystal display device can be considerably reduced even if only a part of the PCB 220 is removed due to the metallic material.

Since the plurality of metal wires (not shown) formed on the PCB 220 are formed so as to be surrounded by the outer peripheries of the LEDs 210 so as not to overlap each other, the first width h1 of the PCB 220 There is a limit to reduce.

At this time, the LED assembly 200 including the PCB 220 is installed at one end of the cover bottom (150 in FIG. 2) so that the light incident surfaces of the LEDs 210 and the light guide plate 123 This causes increase in the thickness of the liquid crystal display device.

2) of the cover bottom (150 in FIG. 2) formed on the horizontal surface (151 in FIG. 2) of the PCB 220. However, The thickness of the liquid crystal display device can be reduced by the width of the PCB 220 that is inserted into the horizontal surface 151 of FIG. 2 (see FIG. 2) of the cover bottom (150 in FIG. 2).

In addition, the fixing force of the LED assembly 200 can be improved.

4A and 4B are perspective views schematically illustrating attachment and fixing of the LED assembly according to the embodiment of the present invention.

As shown in the figure, a plurality of LEDs 210 are mounted on the PCB 220 at a predetermined interval. One side of the PCB 220, on which the LEDs 210 are mounted, An adhesive material 160 such as a double-sided tape is disposed on the back side of the upper side of the upper surface.

The adhesive material 160 such as the LED assembly 200 and the double-sided tape is adhered and fixed to the inside of the side surface 153 of the one edge of the cover bottom 150.

The cover bottom 150 includes a horizontal surface 151 and a side surface 153 vertically bent upward at an edge of the bottom surface 151. The horizontal surface 151 of the edge portion of the LED assembly 200, And a hole 155 corresponding to the convex portion 223 of the convex portion 220 is formed.

Here, the holes 155 are spaced apart from the side surface 153 of the cover bottom 150 by the thickness of the adhesive material 160 such as a double-sided tape, and the LEDs 210 of the PCB 220 The convex portion 223 exposed to the outside is inserted.

Therefore, the thickness of the liquid crystal display device can be reduced by the width of the convex portion 223 of the PCB 220 inserted into the hole 155.

The convex portion 223 of the PCB 220 inserted into the hole 155 is narrower or thicker than the thickness of the horizontal surface 151 of the cover bottom 150 so that the convex portion 223 of the PCB 220, So as not to be exposed to the backside of the cover bottom 150.

The LED assembly 200 is attached and fixed to the inside of the side surface 153 of the cover bottom 150 through an adhesive material 160 such as a double-sided tape positioned on the back surface of the LED assembly 200, Since the convex portion 223 of the PCB 220 of the assembly 200 is inserted and inserted into the hole 155 of the cover bottom 150, the fixing force of the LED assembly 200 is improved.

Particularly, since the convex portion 223 of the PCB 220 of the LED assembly 200 is inserted into the hole 155, the position of the LED assembly 200 can be precisely aligned, and the LED assembly 200 Can be attached and fixed at an accurate position, and it is possible to prevent the LED assembly 220 from being distorted.

Accordingly, it is possible to prevent the light loss of the LED assembly 200 from occurring and improve the brightness of the liquid crystal display device.

Further, the reliability of the product is improved, and workability and productivity are improved.

Further, the LED assembly 200 of the present invention can reduce the process material cost. This is because unnecessary material costs can be prevented from increasing.

5 is a plan view schematically illustrating formation of a PCB base of the PCB of the present invention.

4B, the PCB base 225 of the PCB 220 is formed by separating a plurality of PCB bases 225 from the base board 300 in the form of a ledge by a punching method for removing unnecessary portions. The PCB of the invention (220 in FIG. 4B) is formed in a concave-convex shape at one edge in the longitudinal direction, so that two PCB bases 225 are paired on the base substrate 300 to form a pair of recesses 221 and protrusions 223 Can be formed to be sandwiched each other.

That is, the concave portion 221 of one PCB base 225 is formed to form the convex portion 223 of another PCB base 225 in the area to be removed.

Therefore, an unnecessary part of the PCB base 221 can be reduced, and unnecessary material costs can be prevented from increasing.

Therefore, the process material cost can be reduced.

4B) of the LED assembly (200 in FIG. 4B) is formed into a concavo-convex shape including a concave portion 221 and a convex portion 223 in the longitudinal direction of the PCB (220 in FIG. 4B) 4B) of the PCB (220 in FIG. 4B) of the horizontal surface (151 in FIG. 4B) corresponding to one edge of the cover bottom (150 in FIG. 4B) By forming the hole (155 in Fig. 4B) that can be inserted, a lightweight and thin liquid crystal display device is provided.

In addition, in the process of attaching the LED assembly 200 (FIG. 4B), the efficiency of the process can be improved and the fixing force of the LED assembly 200 (FIG. 4B) can be improved. Accordingly, it is possible to prevent the LED assembly (200 of FIG. 4B) from being distorted, and to prevent the light loss of the LED assembly (200 of FIG. 4B) from being generated.

Further, the material cost can be reduced by the recess (221 in Fig. 4B) of the PCB (220 in Fig. 4B).

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.

150: cover bottom (151: horizontal plane, 153: side, 155: hole)
160: Adhesive material
200: LED assembly
210: LED
220: PCB (221: lumbar region, 223: convex)

Claims (9)

A reflector;
A light guide plate mounted on the reflection plate;
An LED assembly including a plurality of LEDs arranged along the light incidence plane of the light guide plate, and a PCB having the plurality of LEDs mounted thereon, the PCB including a concave portion and a convex portion at one edge in the longitudinal direction;
A liquid crystal panel mounted on the light guide plate;
A horizontal plane in close contact with the reflection plate, and a cover bottom
Wherein the horizontal surface is provided with a hole into which the convex portion is inserted,
The plurality of LEDs are located on the convex portion of the PCB,
Wherein the recess is located between the plurality of LEDs, and each of the recesses corresponds to a size of each of the plurality of LEDs.
The method according to claim 1,
The PCB has a long bar shape, and the PCB has a first width corresponding to the convex portion and a second width corresponding to the concave portion perpendicularly to the length direction.
3. The method of claim 2,
And the second width is 1/3 to 1/2 of the first width.
The method of claim 3,
And the hole exposed to the outside of the LED is inserted into the hole.
5. The method of claim 4,
And a portion of the convex portion inserted into the hole is equal to or smaller than the thickness of the cover bottom.
The method according to claim 1,
Wherein the LED assembly is attached to the side surface through an adhesive material.
The method according to claim 1,
Wherein the PCB comprises a metal printed circuit board (MCPCB), a flame resistor (FR-4), or a T-preg.
The method according to claim 1,
And an optical sheet between the light guide plate and the liquid crystal panel.
The method according to claim 1,
And a top cover including a support main covering an edge of the liquid crystal panel and having a top edge of the liquid crystal panel and being coupled to the support main and the cover bottom.

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