KR20100137866A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: A liquid crystal display device is provided to remove the level difference of the inside of the modulated liquid crystal display thereby preventing the damage of the corresponding part in the hydrostatic test. CONSTITUTION: A support main(130) is the shape of frame of square. A backlight unit is located inside of the support main. The first and second polarizers(119a, 119b) are respectively attached to each exterior of the first substrate and the second substrate. A cover bottom(150) is composed adhering to the rear side of the support main.

Description

Liquid crystal display device

The present invention relates to a liquid crystal display device, and more particularly, to a chip on glass (COG) type liquid crystal display device.

A liquid crystal display device displays an image using the optical anisotropy and polarization property of the liquid crystal. Since the liquid crystal has a thin and long molecular structure, the liquid crystal has directivity in the arrangement of molecules, and the liquid crystal can be artificially applied to control the direction of the molecular arrangement.

Therefore, if the molecular arrangement direction of the liquid crystal is arbitrarily adjusted, the molecular arrangement of the liquid crystal is changed, and the polarization state of light is changed in the molecular arrangement direction of the liquid crystal due to optical anisotropy, thereby displaying an image.

Accordingly, a liquid crystal display device includes a liquid crystal panel in which a pair of first and second substrates having a transparent field generating electrode formed on a surface facing each other with a liquid crystal layer interposed therebetween, and a backlight for supplying light thereto. backlight), and by controlling the electric field between two field generating electrodes of the liquid crystal panel to artificially adjust the direction of the liquid crystal molecules to generate a difference in transmittance and to pass the light generated from the backlight through such a liquid crystal panel difference in the transmittance Is displayed to the outside to display various images.

The outer portion of the liquid crystal panel is configured to drive a driving unit, which is connected to a printed circuit board (PCB) on which components generating various control signals and data signals, a liquid crystal panel and a printed circuit board, and is connected to the liquid crystal panel. And a driving integrated circuit (IC) for applying a signal to the wiring line.

Chip on glass (COG) tape carrier package (TCP) chip on film (COF) The COG method has been widely used in recent years because the structure of the COG method is simpler than that of the TCP method and the COF method, and the ratio of the liquid crystal panel to the liquid crystal display device can be increased.

1 is an exploded perspective view of a liquid crystal display device including the COG type liquid crystal panel. In the liquid crystal panel 10 having the above-described configuration, the first substrate 12 and the second substrate 14 are formed of a liquid crystal layer (not shown). It is in a state of being joined when facing each other with the si) in between.

At this time, since the first substrate 12 has a larger area than the second substrate 14, when the bonding is performed, one edge of the first substrate 12 is exposed to the outside. The driving integrated circuit 15 is configured to apply a signal to the gate line and the data line.

The driving integrated circuit 15 is a plurality of gate and data driving integrated circuits, and the gate and data driving integrated circuit 15 is connected to gates and data wirings (not shown) on the first substrate 12, respectively.

The driving integrated circuit 15 is connected to an external printed circuit board (not shown) through the FPC 20.

In addition, a backlight unit 20, which is a dimming means, is provided on the rear surface of the liquid crystal panel 10, and the liquid crystal panel 10 and the backlight unit 20 are supported by the support main 30 and the cover bottom 50. It is modular.

In this case, the backlight unit 20 includes an LED assembly 24 arranged along at least one edge length direction of the support main 30, a white or silver reflecting plate 25 mounted on the cover bottom 50, and the like. The light guide plate 23 mounted on the reflective plate 25 and having the LED assembly 24 positioned on one side thereof and includes a plurality of optical sheets 21 interposed thereon.

In this case, the LED assembly 24 includes a plurality of LEDs 24a and PCBs 24b on which the LEDs 24a are mounted at predetermined intervals.

On the other hand, with the recent increase in the demand for liquid crystal display devices, the problem of quality has emerged. Accordingly, the inspection step in the manufacturing process of the liquid crystal display device is the most important process is subjected to various tests.

Among these, as an inspection step for testing the durability of the liquid crystal display device, a positive pressure test is applied to apply pressure to the liquid crystal display device. This is a test to check the durability of the liquid crystal display by applying a constant pressure to a specific point of the liquid crystal display.

2 is a front view showing a specific point for the positive pressure test of the liquid crystal display.

As shown, the liquid crystal panel 10 and the backlight unit 20 of FIG. 1 are modularized through the support main 30 and the cover bottom 50.

The modular liquid crystal display device performs a constant pressure test by applying a constant pressure to a total of seven specific points (①②③④⑤⑥⑦).

Table 1 below shows the static pressure test results of eight liquid crystal displays.

Sample 1 Sample 2 Sample 3 Sample 4 Sample 5 Sample 6 Sample 7 Sample 8 point 1 No damage No damage No damage No damage No damage No damage No damage No damage point 2 No damage 15kgf No damage No damage 15kgf No damage No damage No damage point 3 No damage No damage 13.67kgf 13kgf No damage 13kgf 14.13kgf No damage point 4 No damage No damage No damage No damage No damage No damage No damage No damage point 5 No damage No damage No damage No damage No damage No damage No damage No damage point 6 No damage No damage No damage No damage No damage No damage No damage No damage point 7 No damage No damage No damage No damage No damage No damage No damage No damage

Table (1)

The static test shall not cause breakage when pressure of at least 15 kgf is applied.

However, referring to Table 1, it can be seen that the breakdown of the liquid crystal display device frequently occurs even at a pressure of 15 kgf or less at the point ③ during the static pressure test.

The liquid crystal display device in which such breakage has occurred should be discarded.

Through this, there is a disadvantage in that the process yield is lowered and the process cost is increased.

On the other hand, the region corresponding to the point ③ of the liquid crystal display device is the region corresponding to the boundary of the polarizing plate (not shown) attached to the outer surface of the first substrate 12 of the COG type liquid crystal panel 10, and the first substrate 12. The polarizing plate (not shown) attached to the outer surface of the () is attached without covering the pad region on which the driving direct circuit (15 of FIG. 1) is mounted.

Therefore, a method for improving the static pressure strength of its region should be provided.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a first object of the present invention is to improve the static pressure strength of a liquid crystal display device.

Through this, the second purpose is to increase the process yield and reduce the process cost.

In order to achieve the object as described above, the present invention and the main frame of the rectangular frame; A backlight unit located inside the support main; A liquid crystal panel comprising a first substrate seated on the backlight unit and a second substrate bonded to each other with the first substrate and the liquid crystal layer interposed therebetween; First and second polarizers attached to respective outer surfaces of the first and second substrates, respectively; A cover bottom configured to be in close contact with the support main back surface; A top cover is formed around the top edge of the liquid crystal panel and is coupled to the support main and the cover bottom. The first polarizing plate provides a liquid crystal display having the same size as the first substrate.

In this case, the driving integrated circuit is mounted on the edge of the first substrate is a COG type, the backlight unit includes a reflector and a light guide plate, a plurality of optical sheets and a light source arranged on one side of the light guide plate.

In addition, the backlight unit includes a reflector, a plurality of optical sheets, and a plurality of light sources arranged on the reflector.

As described above, in the present invention, the first polarizing plate is formed to extend to the end of the first substrate, thereby removing the step in the modular liquid crystal display device, thereby preventing damage to the corresponding site during the positive pressure test. It has an effect.

Through this, there is an effect that can increase the process yield and reduce the process cost.

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

The present invention can be applied to mobile phones, digital multimedia broadcasting (DMB) terminals, small liquid crystal display devices mounted on PDAs (personal digital assistants) and digital cameras, and large liquid crystal display devices used in TVs or computer monitors. In the following, a small liquid crystal display manufactured to 5 inches or less will be described as an example.

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

As shown, the liquid crystal display device includes a liquid crystal panel 110, a backlight unit 120, a support main 130, and a cover bottom 150.

First, the liquid crystal panel 110 plays a key role in image expression and includes a first substrate 112 and a second substrate 114 bonded to each other with the liquid crystal layer interposed therebetween.

In this case, under the premise of an active matrix method, although not shown in the drawings, a plurality of gate lines and data lines intersect with each other and a pixel is defined on an inner surface of the first substrate 112, commonly referred to as a lower substrate or an array substrate. Thin film transistors (TFTs) are provided at each intersection to correspond one-to-one to the transparent pixel electrodes formed in each pixel.

In addition, the inner surface of the second substrate 114 called the upper substrate or the color filter substrate may correspond to each pixel, for example, a color filter of red (R), green (G), and blue (B) color, and each of them. A black matrix covering the non-display elements such as gate lines, data lines, and thin film transistors is provided. In addition, a transparent common electrode covering them is provided.

In this case, the pad region is additionally provided in the first substrate 112 as compared with the second substrate 114, so that the area of one edge is larger. Accordingly, a driving integrated circuit 115 for applying signals to a plurality of gate lines and data lines is formed in the pad region, which is one edge of the first substrate 112.

Such a structure is referred to as a chip on glass (COG) liquid crystal panel 100. The COG method uses an anisotropic conductive film (ACF) to directly drive the driving integrated circuit 115 on the first substrate 112. As a method of adhering, the ratio of the liquid crystal panel 110 to the liquid crystal display device can be increased.

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

The driving integrated circuit 115 is connected to an external printed circuit board (not shown) through an FPC (not shown).

Although not clearly shown in the drawings, upper and lower alignment layers (not shown) for determining the initial molecular alignment direction of the liquid crystal are interposed between the two substrates 112 and 114 of the liquid crystal panel 110 and the liquid crystal layer. In order to prevent leakage of the liquid crystal layer filled therebetween, a seal pattern is formed along edges of both substrates 112 and 114.

The first and second polarizing plates 119a and 119b are attached to the outer surfaces of the first and second substrates 112 and 114, respectively.

In this case, the first polarizing plate 119a attached to the outer surface of the first substrate 112 extends to the end of the first substrate 112 and is attached to the front surface. That is, the first polarizing plate 119a has the same size as the first substrate 112.

Accordingly, in the liquid crystal panel 110 having the above-described structure, when the thin film transistor selected for each gate line is turned on by the on / off signal transmitted through the scan, the signal voltage is transferred 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 electrode and the common electrode, indicating a difference in transmittance.

A backlight unit 120 for supplying light is provided on a rear surface of the liquid crystal panel 110 such that a difference in transmittance of the liquid crystal panel 110 is expressed to the outside.

The backlight unit 120 includes a LED assembly 124, a white or silver reflector 125, a light guide plate 123 mounted on the reflector 125, and a plurality of optical sheets 121 interposed thereon. Include.

The LED assembly 124 described above is located at one side of the light guide plate 123 to face the light incident surface of the light guide plate 123, and the LED assembly 124 has a plurality of LEDs 124a and its LEDs 124a. It includes a PCB (124b) that is mounted spaced apart.

In this case, the plurality of LEDs 124a emits light having red (R), green (G), and blue (B) colors toward the light-receiving surface of the light guide plate 123, respectively, and the plurality of RGB LEDs 124a. ) Can be lit at once to realize white light by color mixing.

On the other hand, by using the LED 124a configured with an LED chip (not shown) that emits all the colors of RGB, each of the LEDs 124a may be implemented to implement white light, or include a chip that emits white light. It is also possible to use LED 124a to emit light.

In addition, a plurality of LEDs 124a emitting RGB light may be bundled and mounted in a cluster, and the plurality of LEDs 124a mounted on the PCB 124b may be arranged on the PCB 124b. It is also possible to arrange them side by side or to arrange them side by side in a plurality of columns.

In addition, the plurality of LEDs 124a may be mounted on an FPC (not shown) other than the PCB 124b.

In this case, a fluorescent lamp such as a cold cathode fluorescent lamp or an external electrode fluorescent lamp may be used instead of the LED assembly 124. When using such a fluorescent lamp may further include a lamp guide (not shown).

The light guide plate 123 evenly spreads the light incident from the LED 124a to a wide area of the light guide plate 123 while propagating through the light guide plate 123 by several total reflections to provide a surface light source to the liquid crystal panel 110.

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

Here, the pattern may be configured in various ways, such as an elliptical pattern, a polygon pattern, a hologram pattern, and the like to guide the 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 reflective plate 125 is positioned on the rear surface of the light guide plate 123, and reflects light passing through the rear surface of the light guide plate 123 toward the liquid crystal panel 110 to improve the brightness of the light.

The plurality of optical sheets 121 on the light guide plate 123 include a diffusion sheet and at least one light collecting sheet, and diffuse or condense the light passing through the light guide plate 123 to provide a more uniform surface to the liquid crystal panel 110. Allow the light source to enter.

The liquid crystal panel 110 and the backlight unit 120 are modularized through the support main 130 and the cover bottom 150. The liquid crystal panel 110 and the backlight unit 120 are seated so that the entire structure of the LCD module. The cover bottom 150, which is the basis of the assembly, is configured by vertically bending the four edges thereof at a predetermined plate shape in a rectangular shape.

Then, the support main 130 having a rectangular frame shape seated on the cover bottom 150 and surrounding the edges of the liquid crystal panel 110 and the backlight unit 120 is combined with the cover bottom 150.

That is, the liquid crystal panel 110 and the backlight unit 120 of the present invention may prevent the detachment of the backlight unit 120 while the edge is surrounded by the support main 130.

At this time, the adhesive tape (not shown) may prevent desorption of the liquid crystal panel 110 by surrounding the upper and side surfaces of the four edges of the liquid crystal panel 110.

Thus, the liquid crystal display device of the present invention can be thin in the liquid crystal display module by removing the existing top cover, and the effect of simplifying and reassembling the process is brought.

In addition, due to the deletion of the top cover made of a metal material, it is possible to reduce the process cost.

The support main 130 may be referred to as a guide panel or a main support and a mold frame, and the cover bottom 150 may be referred to as a bottom cover or a lower cover.

In this case, the backlight unit 120 having the above-described structure is generally referred to as a side light method, and includes a plurality of sets of the LED assembly 124 in accordance with the purpose, respectively, along both edges of the support main 130 facing each other. Correspondingly intervening is also possible.

In addition, a direct type in which a plurality of LED assemblies 124 are arranged side by side on the upper front surface of the reflecting plate 125 may be possible. In this case, the light guide plate 123 may be omitted.

On the other hand, the liquid crystal display is subjected to a positive pressure test to test the durability of the liquid crystal display, in this case, when referring to Figure 2 and Table (1) during the positive pressure test, a total of seven specific of the modular liquid crystal display Among the points ①②③④⑤⑥⑦, breakage of the liquid crystal display device frequently occurs even at a pressure of 15 kgf or less at the ③ point.

However, the liquid crystal display of the present invention does not cause breakage at any point during the positive pressure test, in which the first polarizing plate 119a attached to the outer surface of the first substrate 112 extends to the end of the first substrate 112. This is because it is attached to the front. This will be described in more detail with reference to FIG. 4.

4 is a schematic cross-sectional view of some cross-section of FIG. 3 modularized.

As illustrated, the reflective plate 125, the light guide plate 123, the LED assembly 124 provided on one side of the light guide plate 123, the light guide plate 123, and a plurality of optical sheets on the light guide plate 123. 121 are stacked to form a backlight unit.

The light shielding tape 122 further includes a light shielding tape 122 between the plurality of optical sheets 121 and the liquid crystal panel 110 to prevent light from leaking to portions outside the screen display area of the liquid crystal panel 110.

The backlight unit and the liquid crystal panel 110 having a liquid crystal layer (not shown) interposed therebetween are disposed between the first and second substrates 112 and 114 and the first second substrates 112 and 114. On each outer surface of the first and second polarizing plates 119a and 119b for selectively transmitting only specific light are attached.

The backlight unit and the liquid crystal panel 110 have an edge surrounded by the support main 130, and the cover bottom 150 is coupled to the rear surface thereof.

Meanwhile, the first polarizing plate 119a attached to the outer surface of the first substrate 112 of the present invention has the same size as the first substrate 112 and extends to the end of the first substrate 112 and is attached to the front surface.

As a result, the step is eliminated in the modular liquid crystal display.

That is, the first polarizing plate 119a of the conventional liquid crystal display device is formed to have the same size as the second polarizing plate 119b, and thus does not cover the pad portion on which the driving direct circuit 115 of the first substrate 112 is mounted. Through this structure, a step occurs in the modular liquid crystal display.

This step causes damage to the site during the static pressure test.

Table 2 below shows breakage of the liquid crystal display device during the positive pressure test due to a step in the liquid crystal display device.

Step difference 0mm 0.8mm step Sample 1 100kgf no damage 10.08kgf Sample 2 100kgf no damage 6.81kgf Sample 3 100kgf no damage 9.12kgf Sample 4 100kgf no damage 7.19kgf Sample 5 100kgf no damage 9.20kgf Average 8.48kgf

Table (2)

As can be seen from Table (2), if there is no step in the liquid crystal display, the liquid crystal display does not break even under 100kgf pressure during the positive pressure test, but if there is a 0.8mm step in the liquid crystal display, the average pressure is 8.48kgf. It can be seen that breakage of the liquid crystal display occurs.

Through this, it can be seen how much the step in the liquid crystal display device affects the durability of the liquid crystal display device.

However, the liquid crystal display of the present invention attaches the first polarizing plate 119a to extend to the end of the first substrate 112, that is, to the pad portion on which the driving direct circuit 115 of the first substrate 112 is mounted. Therefore, the step in the modular liquid crystal display device can be eliminated.

Through this, it is possible to prevent the breakage of the site during the static pressure test.

Thus, by discarding the existing broken liquid crystal display device, it is possible to solve the problem of reduced process yield and increased process cost.

Table 3 below shows the results of the positive pressure test of a total of eight liquid crystal display devices when the first polarizing plate 119a is extended to the end of the first substrate 112 according to the embodiment of the present invention.

Sample 1 Sample 2 Sample 3 Sample 4 point 1 No damage No damage No damage No damage point 2 No damage No damage No damage No damage point 3 25kgf no damage 22kgf no damage 22kgf no damage 23kgf no damage point 4 No damage 22kgf no damage 23kgf no damage 23kgf no damage point 5 No damage No damage No damage No damage point 6 No damage No damage No damage No damage point 7 No damage No damage No damage No damage

Table (2)

Here, each point represents a total of seven specific points (①②③④⑤⑥⑦) shown in FIG. 2, and the static pressure test should not cause breakage when applying a pressure of at least 15 kgf.

Referring to Table (3), it can be seen that the breakage does not occur at the ③ point, which was frequently caused by the existing breakage, and especially endures the pressure of 22 kgf or more at the ③ point and the ④ point.

On the other hand, Table 4 below shows the result of the positive pressure test when the first polarizing plate is formed to the same size as the second polarizing plate and a separate pad is formed at the end of the first substrate in order to remove the step in the liquid crystal display. to be.

Liquid crystal panel including a separate pad for removing the step Sample 1 3.66kgf Sample 2 3.46kgf Sample 3 3.78kgf Sample 4 6.20kgf Sample 5 4.30kgf Average 4.28kgf

Table (4)

Referring to Table 4, when the first polarizing plate 119a is formed in the same manner as before and a separate pad (not shown) is attached, the first polarizing plate 119a is 0.8 mm in the liquid crystal panel 110 of Table 2 described above. It can be seen that the liquid crystal display is damaged at a lower pressure than when there is a step.

Therefore, in order to improve the durability of the liquid crystal display, it can be seen that the most efficient method is to extend the first polarizing plate 119a to the end of the first substrate 112.

As described above, the liquid crystal display of the present invention is formed by extending the first polarizing plate 119a to the end of the first substrate 112, thereby eliminating the step in the modular liquid crystal display, thereby, the positive pressure test This can prevent damage to the site.

Thus, by discarding the existing broken liquid crystal display device, it is possible to solve the problem of reduced process yield and increased process cost.

Meanwhile, in the liquid crystal display of the present invention, the second polarizing plate 119b is attached to the outer surface of the second substrate 114 of the liquid crystal panel 110, and then the driving direct circuit 115 is applied to the pad portion of the first substrate 112. ), It is preferable to attach the first polarizing plate 119a to the outer surface of the first substrate 112.

This is because the first polarizing plate 119a, which extends and is attached to the pad portion on which the driving direct circuit 115 of the first substrate 112 is mounted, may be lifted up and bubbled due to high heat during the mounting process of the driving direct circuit 115. Because it can.

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

1 is an exploded perspective view of a liquid crystal display device including a COG type liquid crystal panel.

2 is a front view showing a specific point for the positive pressure test of the liquid crystal display.

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

4 is a schematic cross-sectional view of a partial cross section of FIG. 3 modularized;

Claims (4)

A support frame having a rectangular frame shape; A backlight unit located inside the support main; A liquid crystal panel comprising a first substrate seated on the backlight unit and a second substrate bonded to each other with the first substrate and the liquid crystal layer interposed therebetween; First and second polarizers attached to respective outer surfaces of the first and second substrates, respectively; A cover bottom configured to be in close contact with the support main back surface; A top cover that covers an upper edge of the liquid crystal panel and is coupled to the support main and the cover bottom And a first polarizing plate having the same size as the first substrate. The method of claim 1, And a COG type in which a driving integrated circuit is mounted along one edge of the first substrate. The method of claim 1, The backlight unit includes a reflective plate, a light guide plate, a plurality of optical sheets and a light source arranged on one side of the light guide plate. The method of claim 1, The backlight unit includes a reflective plate, a plurality of optical sheets and a plurality of light sources arranged on the reflecting plate.

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