KR101957143B1 - Lliquid crystal display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device, A backlight unit disposed at a lower portion of the liquid crystal panel, the backlight unit including a light guide plate including a body and a projection protruding downward from an edge of the body; and a LED assembly disposed at one side of the light guide plate; A main frame surrounding a side surface of the liquid crystal panel and the backlight unit; A bottom frame covering the bottom of the backlight unit and engaging with the main frame; And an adhesive layer formed on an edge of the bottom frame and in contact with a lower surface of the protrusion, wherein the light guide plate is fixed to the bottom frame by the adhesive layer.

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 having improved rigidity.

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 schematic exploded perspective view of a conventional liquid crystal display device.

1, a general liquid crystal display device 1 includes a liquid crystal panel 10, a backlight unit 20, a main frame 30, and a bottom frame 50.

The liquid crystal panel 10 is composed of a first substrate 12 and a second substrate 14 which are in contact with each other with a liquid crystal layer (not shown) therebetween.

First and second polarizers 19a and 19b selectively transmitting only specific light are attached to the outer sides of the first and second substrates 12 and 14, respectively.

A printed circuit board 17 is connected to a neighboring side surface of the liquid crystal panel 10 via a connection member 16 such as a flexible circuit board or a tape carrier package (TCP) Or the back surface of the bottom frame 50, as shown in Fig.

The backlight unit 20 is positioned on the rear surface of the liquid crystal panel 10 and supplies light to the liquid crystal panel 10.

The backlight unit 20 includes a light emitting diode (LED) assembly 29 arranged along the longitudinal direction of at least one side edge of the main frame 30, a reflection plate 25 seated on the bottom frame 50, A light guide plate 23 resting on the reflection plate 25, and an optical sheet 21 interposed therebetween.

The LED assembly 29 includes an LED 29a located on one side of the light guide plate 23 and an LED printed circuit board 29b on which the LED 29a is mounted.

The liquid crystal panel 10 and the backlight unit 20 are coupled to each other by a bottom frame 50 which covers the backside of the backlight unit 20 while the edges of the liquid crystal panel 10 and the backlight unit 20 are surrounded by a main frame 30, 30).

A force may be applied to the liquid crystal display device 1 from the outside, and a pressure at the center of the liquid crystal display device 1 is pressed by a predetermined pressure to measure the pressure of the liquid crystal display device 1 to check its durability.

However, in the conventional liquid crystal display device 1, there is a problem that the liquid crystal panel 10 is easily broken by external pressure.

The present invention aims to solve the problem of breakage due to a decrease in rigidity of a liquid crystal display device.

In order to solve the above problems, the present invention provides a liquid crystal display comprising: a liquid crystal panel; A backlight unit disposed at a lower portion of the liquid crystal panel, the backlight unit including a light guide plate including a body and a projection protruding downward from an edge of the body; and a LED assembly disposed at one side of the light guide plate; A main frame surrounding a side surface of the liquid crystal panel and the backlight unit; A bottom frame covering the bottom of the backlight unit and engaging with the main frame; And an adhesive layer formed on an edge of the bottom frame and in contact with a lower surface of the protrusion, wherein the light guide plate is fixed to the bottom frame by the adhesive layer.

In another aspect, the present invention provides a liquid crystal display comprising: a liquid crystal panel; A light guide plate disposed at a lower portion of the liquid crystal panel and including a body and a first protrusion protruding from the edge of the body in parallel with the liquid crystal panel; A main frame surrounding a side surface of the liquid crystal panel and the backlight unit; And a bottom frame which covers a lower portion of the backlight unit and is coupled to the main frame and has a first hole corresponding to the first projection, the first projection being inserted into the first hole, And the liquid crystal display device is fixed to the frame.

In the liquid crystal display device of the present invention, the backlight unit includes an optical sheet positioned between the light guide plate and the liquid crystal panel.

In the liquid crystal display device of the present invention, the backlight unit may include a reflector positioned between the light guide plate and the bottom frame.

In the liquid crystal display device of the present invention, the backlight unit may include a reflection plate positioned between the light guide plate and the bottom frame, and the reflection plate may be located inside the projection.

In the liquid crystal display device of the present invention, the main frame has a second hole corresponding to the first hole, and the first projection is inserted into the first hole through the second hole.

The liquid crystal display according to the present invention may further comprise an adhesive layer formed on an edge of the bottom frame, wherein the light guide plate includes a second protrusion protruding downward from an edge of the body, And is fixed to the bottom frame.

In the present invention, since the light guide plate is fixed and prevented from flowing, the rigidity of the liquid crystal display device is increased. Therefore, it is possible to minimize the breakage of the liquid crystal panel even if external force is applied to the liquid crystal display device.

That is, an opening is formed in the bottom frame and the edge of the light guide plate is horizontally protruded to be inserted into the bottom frame, thereby fixing the light guide plate, thereby preventing breakage of the liquid crystal panel due to the flow of the light guide plate.

On the other hand, since the edge of the light guide plate is protruded downward and the adhesive layer is provided on the edge of the bottom frame, flow of the light guide plate can be prevented, and breakage of the liquid crystal panel can be prevented.

1 is a schematic exploded perspective view of a conventional liquid crystal display device.
2 is a view showing a rigidity test of the liquid crystal display device.
3 is a schematic cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention.
4 is a schematic cross-sectional view of a liquid crystal display device according to a second embodiment of the present invention.
5 is a schematic plan view showing a structure in which a light guide plate is fixed to a bottom frame in a liquid crystal display device according to a second embodiment of the present invention.
6 is a graph showing an improvement in rigidity of a liquid crystal display device according to an embodiment of the present invention.

As described above, in the conventional liquid crystal display device, the liquid crystal panel is easily broken in a rigidity test that externally applies pressure.

2 showing a rigidity test of the liquid crystal display device, when a force is applied to the liquid crystal display device 1, the light guide plate 23 flows upward and downward, and the liquid crystal panel 10 is broken due to the stress .

The light guide plate 23 is seated on the bottom frame 50 with the reflector 23 interposed therebetween and a step is formed at the edge of the light guide plate 23 and the main frame 30 is seated at the edge step of the light guide plate 23. At this time, since there is no fixing structure of the light guide plate 23, if a force is externally applied, the flow of the light guide plate 23 occurs and the liquid crystal panel 10 is damaged due to the stress.

Hereinafter, an embodiment capable of preventing the breakage of the liquid crystal panel by increasing the rigidity of the liquid crystal display device will be described.

3 is a schematic cross-sectional view of a liquid crystal display device according to a first embodiment of the present invention.

3, the liquid crystal display 100 according to the first embodiment of the present invention includes a liquid crystal panel 110, a backlight unit 120, a main frame 130, a bottom frame 150, 160). 3 shows a structure in which a top frame for covering the edge of the liquid crystal panel 110 is omitted, but it is natural that a top frame may be included.

The liquid crystal panel 110 is composed of first and second substrates 112 and 114 which are bonded to each other with a liquid crystal layer (not shown) therebetween.

Although not shown, a plurality of gate lines and data lines intersect each other on the inner surface of a first substrate 112 called a lower substrate or an array substrate, pixels are defined, and a thin film transistor (TFT) TFTs) 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 non-display elements such as a gate line, a data line and a thin film transistor. In addition, a transparent common electrode covering these elements is provided.

Alternatively, the pixel electrode and the common electrode may be formed on the first substrate 112 and alternately arranged in the pixel regions.

When a signal is applied to the gate line to turn on the thin film transistor, a signal is applied to the pixel electrode through the data line. As a result, an electric field is formed between the pixel electrode and the common electrode, and the liquid crystal molecules of the liquid crystal layer are driven by the electric field.

Although not shown, a gate and a data printed circuit board are connected to each other via a connecting member such as a flexible circuit board along at least one edge of the liquid crystal panel 110, and the main frame 130 is closely contacted during the module process.

An alignment film (not shown) for determining the initial alignment direction of the liquid crystal is interposed between the first and second substrates 112 and 114 and the liquid crystal layer of the liquid crystal panel 110, A seal pattern (not shown) is formed along edges of the first and second substrates 112 and 114 to prevent leakage of the liquid crystal layer.

First and second polarizers 119a and 119b are attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

The backlight unit 120 is positioned below the liquid crystal panel 110 and supplies light. As described above, since the liquid crystal molecules of the liquid crystal layer are driven to generate a difference in transmittance generated externally, Image.

The backlight unit 120 includes a light guide plate 123, a reflection plate 125, an optical sheet 121, and an LED assembly 129.

The light guide plate 123 is disposed under the liquid crystal panel 110 and includes a body 123a and a protrusion 123b projecting downward from at least one side of the body 123a.

That is, the body 123a of the light guide plate 123 is a rectangular plate that covers the liquid crystal panel 110, and the protrusion 123b of the light guide plate 123 extends from the body 123a to the bottom of the bottom frame 150 And protrudes toward the liquid crystal panel 110 in the opposite direction.

The reflection plate 125 is positioned on the back surface of the light guide plate 123. The end of the reflection plate 125 may be positioned inside the protrusion 123b of the light guide plate 123.

The optical sheet 121 is positioned above the light guide plate 123, that is, between the liquid crystal panel 110 and the light guide plate 223.

The adhesive layer 160 is positioned below the light guide plate 123 to prevent the light guide plate 123 from flowing. More specifically, the adhesive layer 160 is in contact with the lower surface of the protruding portion 123b of the light guide plate 123. For example, the adhesive layer 160 may be a double-sided tape.

The LED assembly 129 is disposed on one side of the light guide plate 123 and includes an LED 129a and an LED assembly 129b on which the LED 129a is mounted. The light emitted from the LED assembly 129 is incident on the light guide plate 123 and is uniformly spread in the light guide plate 123 by total reflection and becomes a uniform surface light source through the optical sheet 121, 110).

At this time, the reflection plate 125 reflects light from the back surface of the light guide plate 123 to increase light efficiency, and the optical sheet 121 includes at least one diffusion sheet and at least one light condensing sheet to improve optical characteristics .

The main frame 130 surrounds the side surfaces of the liquid crystal panel 110 and the backlight unit 120. For example, the main frame 130 includes a vertical part corresponding to the side surfaces of the liquid crystal panel 110 and the backlight unit 120, and a horizontal part protruding from the vertical part so that the liquid crystal panel 110 can be seated thereon. It can be done in part. At this time, the thickness of the light guide plate 123 decreases corresponding to the protrusion 123b, so that the light guide plate 123 has a stepped portion, and the horizontal portion of the main frame 130 is disposed at the stepped portion.

The bottom frame 150 covers the back surface of the backlight unit 120 and is coupled with the main frame 130 to form a liquid crystal display device 100.

At this time, the adhesive layer 160 is positioned at the edge of the bottom frame 150, and the upper surface of the adhesive layer 160 is in contact with the protrusion 123b of the light guide plate 123 to guide the light guide plate 123 to the bottom frame 150 . Therefore, even when an external force is applied to the liquid crystal display 100, the light guide plate 123 is prevented from vertically moving. Also, horizontal flow of the light guide plate 123 can be prevented. Therefore, it is possible to prevent the liquid crystal panel 110 from being damaged due to the stress caused by the flow of the light guide plate.

The upper surface of the adhesive layer 160 contacts the vertical portion of the main frame 130 to fix the main frame 130. The adhesive layer 160 also contacts the back surface of the reflection plate 125 to prevent the reflection plate 125 from flowing.

3, a space is formed between the reflection plate 125 and the bottom frame 150 by the adhesive layer 160. However, since the adhesive layer 160 is very thin, And comes into contact with the frame 150.

The light guide plate 123 includes a protrusion 123b protruding downward from an edge of the body 123a and the protrusion 123b protrudes downward from the edge of the bottom frame 150. In the liquid crystal display apparatus 100 having the above- And is prevented from flowing.

Accordingly, since the light guide plate 123 is prevented from vertically flowing even if a force is externally applied, the liquid crystal panel is prevented from being damaged by the stress generated by external force due to external force as in the conventional liquid crystal display device .

FIG. 4 is a schematic sectional view of a liquid crystal display device according to a second embodiment of the present invention, and FIG. 5 is a schematic view showing a structure in which a light guide plate is fixed to a bottom frame in a liquid crystal display device according to a second embodiment of the present invention. FIG.

4 and 5, a liquid crystal display device 200 according to the first embodiment of the present invention includes a liquid crystal panel 210, a backlight unit 220, a main frame 230, and a bottom frame 250, . Although FIG. 4 shows a structure in which the top frame for covering the edge of the liquid crystal panel 210 is omitted, it is natural that a top frame may be included.

The liquid crystal panel 210 is composed of first and second substrates 212 and 214 which are bonded to each other with a liquid crystal layer (not shown) therebetween. The first and second substrates 112 and 114 The first and second polarizing plates 219a and 219b are attached.

As described above, a thin film transistor, a pixel electrode, and the like may be formed on the first substrate 112, and a color filter, a common electrode, and the like may be formed on the second substrate 114.

The backlight unit 220 is positioned below the liquid crystal panel 210 and supplies light. As described above, since the liquid crystal molecules of the liquid crystal layer are driven to generate a difference in transmittance generated externally, Image.

The backlight unit 220 includes a light guide plate 223, a reflection plate 225, an optical sheet 221, and an LED assembly 229.

The light guide plate 223 is disposed below the liquid crystal panel 210 and includes a body 223a and a protrusion 223b projecting horizontally from at least one side of the body 223a.

That is, the body 223a of the light guide plate 223 is a rectangular plate covering the liquid crystal panel 210 and the protrusion 223b of the light guide plate 223 protrudes from the body 223a to the side surface of the bottom frame 150 And extends in parallel with the liquid crystal panel 110. As shown in FIG.

The reflection plate 225 is located on the back surface of the light guide plate 223 and the optical sheet 221 is positioned on the upper side of the light guide plate 223, that is, between the liquid crystal panel 210 and the optical light guide plate 223 .

The LED assembly 229 is disposed on one side of the light guide plate 223 and includes an LED 229a and an LED assembly 229b on which the LED 229a is mounted. The light emitted from the LED assembly 229 is incident on the light guide plate 223 and spreads uniformly in the light guide plate 223 by total reflection and becomes a uniform surface light source through the optical sheet 221, 210).

At this time, the reflection plate 225 reflects light from the back surface of the light guide plate 223 to increase light efficiency, and the optical sheet 221 includes at least one diffusion sheet and at least one light condensing sheet to improve optical characteristics .

The main frame 130 covers the sides of the liquid crystal panel 210 and the backlight unit 220. For example, the main frame 230 may include a vertical portion corresponding to the side surfaces of the liquid crystal panel 210 and the backlight unit 220, and a horizontal portion 240 protruding from the vertical portion so that the liquid crystal panel 210 can be seated thereon. It can be done in part.

The vertical portion of the main frame 230 has a first hole 232 corresponding to the protrusion 223b of the light guide plate 223.

The bottom frame 250 covers the back surface of the backlight unit 220 and is coupled with the main frame 230 to form a liquid crystal display device 200. At this time, the bottom frame 250 has a second hole 252 corresponding to the protrusion 223b of the light guide plate 223. That is, the second hole 252 is formed on the side surface of the bottom frame 250.

The projecting portion 223b of the light guide plate 223 passes through the first hole 232 of the main frame 230 and the second hole 252 of the bottom frame 250. [ That is, the protrusion 223b of the light guide plate 223 is inserted into the second hole 252 of the bottom frame 250 through the first hole 232 of the main frame 230, 230 are fixed by the bottom frame 250.

The light guide plate 223 includes a protrusion 223b protruding horizontally from the edge of the body 223a and the protrusion 223b protrudes horizontally from the edge of the main frame 230. In the liquid crystal display apparatus 200, Is inserted into the second hole (252) formed in the side surface of the bottom frame (250) through the first hole (232) formed in the vertical portion of the bottom frame (250).

Therefore, since the light guide plate 223 is prevented from vertically flowing even if a force is externally applied, the liquid crystal panel is prevented from being damaged by the stress generated by external force due to the external force as in the conventional liquid crystal display device .

An adhesive layer 260 may be formed on the bottom edge of the bottom frame 250 to fix the vertical portion of the main frame 230 and the reflective plate 225.

3) may be further formed on the light guide plate 223 so that the body 223a protrudes from the edge toward the bottom surface of the bottom frame 250 to be adhered to the adhesive layer 260 have.

4 shows a structure in which the vertical portion of the main frame 230 covers the protruding portion 223b of the light guide plate 223 and the first hole 232 is formed. The vertical portion of the frame 230 may be omitted and the protrusion 223b may be inserted directly into the second hole 252 of the bottom frame 250. [

The results of the rigidity test of the conventional liquid crystal display device A and the liquid crystal display devices B and C according to the first and second embodiments of the present invention are shown in FIG. The rigidity test is a result of measuring the force when a force is applied from the front center of the liquid crystal display and the liquid crystal panel is broken. In FIG. 6, the horizontal axis represents a sample number, and the vertical axis represents an external force (unit: N) applied to the liquid crystal display devices 100 and 200.

Average at least maximum A 57.5 42.6 70.1 B 68.5 51.9 98.3 C 73.6 68.1 90.2

6 and Table 1, in the liquid crystal display devices 100 and 200 according to the first and second embodiments of the present invention, the light guide plates 123 and 223 are bonded to the adhesive layer (not shown) by the protrusions 123b and 223b The light guide plates 123 and 223 are prevented from flowing due to an external force and the damage problem of the liquid crystal panels 110 and 210 is minimized since they are fixed to the second holes 252 of the bottom frame 250 or the second holes 252 of the bottom frame 250.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It can be understood that

110, 210: liquid crystal panel 120, 220: backlight unit
123 and 223: light guide plates 123a and 223a: light guide plate body
123b, 223b: a light guide plate projection 125, 225:
121 and 221: Optical sheets 129 and 229: LED assembly
130, 230: main frame 232: first hole
150, 250: bottom frame 252: second hole
160, 260: adhesive layer

Claims (8)

A liquid crystal panel;
A light guide plate disposed at a lower portion of the liquid crystal panel and including a body and a protrusion protruding downward from an edge of the body; an LED assembly disposed at one side of the light guide plate; and a reflector positioned inside the protrusion at a lower portion of the light guide plate A backlight unit including:
A main frame surrounding a side surface of the liquid crystal panel and the backlight unit;
A bottom frame covering the bottom of the backlight unit and engaging with the main frame;
And an adhesive layer formed at an edge of the bottom frame and contacting the lower surface of the protrusion and the lower surface of the reflector,
Wherein the light guide plate and the reflection plate are fixed to the bottom frame by the adhesive layer.
A liquid crystal panel;
A backlight unit disposed at a lower portion of the liquid crystal panel and including a body and a first protrusion protruding from an edge of the body in parallel with the liquid crystal panel; and a LED assembly disposed at one side of the light guide plate;
A main frame surrounding a side surface of the liquid crystal panel and the backlight unit;
And a bottom frame that covers a lower portion of the backlight unit and is coupled to the main frame, the bottom frame having a first hole corresponding to the first projection,
The first projection is inserted into the first hole, the light guide plate is fixed to the bottom frame,
And an adhesive layer formed on an edge of the bottom frame, wherein the light guide plate includes a second protrusion protruding downward from the edge of the body, and the second protrusion is fixed to the bottom frame by the adhesive layer .
3. The method according to claim 1 or 2,
Wherein the backlight unit includes an optical sheet positioned between the light guide plate and the liquid crystal panel.
3. The method of claim 2,
Wherein the backlight unit includes a reflection plate positioned between the light guide plate and the bottom frame.

delete 3. The method of claim 2,
Wherein the main frame has a second hole corresponding to the first hole, and the first projection is inserted into the first hole through the second hole.
delete The method according to claim 1,
Wherein the light guide plate has a stepped portion with a reduced thickness corresponding to the protruding portion, and the main frame includes a horizontal portion disposed at the stepped portion.

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