KR20110073725A - Liquid crystal display device - Google Patents

Abstract

PURPOSE: An LCD device is provided to increase the intensity of radiation by changing an optical path. CONSTITUTION: An upper substrate(200) and a lower plate(100) are facing each other. A liquid crystal layer(300) is formed between the upper substrate and the lower substrate. A lower polarizing plate(160) is formed on the lower surface of the lower plate. A backlight(400) is formed on the bottom of the lower polarizing plate. Optical path change units(500) are formed between the lower polarizing plate and the backlight. The optical path changes the optical path of the light emitted from the backlight. The optical path change units increase the amount of light which transmitted to the upper plate.

Description

[0001] The present invention relates to a liquid crystal display device,

The present invention relates to a liquid crystal display device, and more particularly, to a liquid crystal display device having improved luminance characteristics.

Liquid crystal display devices have a wide range of applications ranging from notebook computers, monitors, spacecrafts, aircrafts, etc. to the advantages of low power consumption and low power consumption.

The liquid crystal display device includes a lower substrate, an upper substrate, and a liquid crystal layer formed between the two substrates, and the arrangement of the liquid crystal layers is adjusted according to whether an electric field is applied, and thus the light transmittance is adjusted to display an image. .

Hereinafter, a conventional liquid crystal display device will be described with reference to the drawings.

1 is a schematic cross-sectional view of a conventional liquid crystal display device.

As can be seen in FIG. 1, a conventional liquid crystal display device includes a lower substrate 10, an upper substrate 20, a liquid crystal layer 30 formed between the lower substrate 10 and the upper substrate 20, and the lower substrate. 10 includes a backlight 40 formed below.

An element layer 14 is formed on the upper surface of the lower substrate 10. The device layer 14 includes a wiring layer 12 such as a gate line and a data line. Although not illustrated, the device layer 14 may include a thin film transistor connected to the wiring layer 12 and a pixel electrode connected to the thin film transistor.

A light shielding layer 22 is formed on a lower surface of the upper substrate 20 to prevent light from leaking to regions other than the pixel region, and red (R) for realizing color is formed in the region between the light shielding layers 22. ), Green (G) and blue (B) color filter layers 24 are formed. Although not shown, a common electrode for forming an electric field together with the pixel electrode is formed on the color filter 24.

The lower polarizing plate 16 is formed on the lower surface of the lower substrate 10, and the upper polarizing plate 26 is formed on the upper surface of the upper substrate 20, so that the polarization direction of the light supplied to the backlight 40 is changed. It can be adjusted.

The backlight 40 is disposed under the lower substrate 10 to supply light toward the lower substrate 10. Although not shown, the backlight 40 may include a light source and various components such as a light guide plate, a diffusion sheet, and the like that may uniformly irradiate the light emitted from the light source toward the lower substrate 10. .

In such a conventional liquid crystal display device, the arrangement state of the liquid crystal layer 30 is changed according to whether an electric field is applied between the pixel electrode and the common electrode, and accordingly, the transmittance of light supplied from the backlight 40 is changed to display an image. It is the principle displayed.

However, such a conventional liquid crystal display device has a disadvantage in that only a part of the light supplied from the backlight 40 is used to display an image and most of the light is lost. That is, the conventional liquid crystal display has a disadvantage in that the light transmittance is lowered and the luminance characteristic is lowered.

As such, the light blocking layer 22 formed on the upper substrate 20 may be cited as a cause of lowering the light transmittance in the conventional liquid crystal display device.

That is, as indicated by the arrow of FIG. 1, the light supplied from the backlight 40 passes through the lower substrate 10, the liquid crystal layer 30, and the upper substrate 20 in turn. Since light does not pass through the area (area A) in which the layer 22 is formed, that much light does not actually contribute to displaying an image and is lost.

Therefore, since a substantial part of the light supplied from the backlight 40 is blocked by the light shielding layer 22, there is a problem in that the light transmittance is lowered and the luminance characteristic is lowered.

The present invention has been devised to solve the above-mentioned conventional problems, and the present invention provides a liquid crystal display device having improved luminance characteristics by improving light transmittance by allowing a substantial portion of light supplied from a backlight to actually display an image. For the purpose of

The present invention, in order to achieve the above object, the upper substrate and the lower substrate facing each other; A liquid crystal layer formed between the upper substrate and the lower substrate; A lower polarizer formed on a lower surface of the lower substrate; A backlight formed under the lower polarizer; And an optical path changing unit formed between the lower polarizing plate and the backlight to change the path of light emitted from the backlight to increase the amount of light supplied to the upper substrate.

The light path changing unit may be formed as a refractive pattern for increasing the amount of light supplied to an area between the light blocking layers by refracting light emitted from the backlight and entering a region corresponding to the light blocking layer formed on the upper substrate.

The light path changing unit may be formed as a reflection pattern for increasing the amount of light supplied to the area between the light blocking layers by reflecting the light emitted from the backlight and entering the area corresponding to the light blocking layer formed on the upper substrate. In this case, in order to guide the light reflected by the light path changing unit toward the upper substrate, it may further include a light inducing unit. The light guide part may be formed of a light reflecting material positioned under a light source of the backlight.

The optical path changing unit may be formed in a pattern corresponding to a gate line, a data line, and a thin film transistor formed in the entire dummy region and the active region on the lower substrate.

The light path changing unit may be formed in a pattern corresponding to the light blocking layer formed on the upper substrate.

The optical path changing unit may be directly patterned on a lower surface of the lower polarizing plate through a printing process, and in this case, a polarizing plate having a wire grid structure may be used as the lower polarizing plate.

The optical path changing part may be formed of a sheet structure having a predetermined pattern, and the sheet structure may be attached on a lower surface of the lower polarizer.

According to the present invention as described above has the following effects.

According to the present invention, the light path changing part is formed between the lower polarizer and the backlight, thereby changing the path of light emitted from the backlight and entering the area corresponding to the light blocking layer, thereby increasing the amount of light supplied to the area between the light blocking layers. That is, according to the present invention, by changing the path of the light to be blocked by the light shielding layer so that the light can contribute to display the image, the light transmittance is enhanced, thereby improving the luminance characteristic.

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

2 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

As can be seen in Figure 2, the liquid crystal display according to an embodiment of the present invention, the lower substrate 100, the upper substrate 200, the liquid crystal layer 300, the backlight 400, the optical path changing unit 500 , And the light induction part 550.

An element layer 140 is formed on an upper surface of the lower substrate 100.

The device layer 140 includes a wiring layer 120 such as a gate line and a data line. Although not shown, the device layer 140 includes a thin film transistor connected to the gate line and the data line, respectively, as a switching element, and also includes a pixel electrode connected to the thin film transistor. In the so-called IPS (In Plane Switching) mode in which the liquid crystal layer 300 is driven through a transverse electric field, a common electrode arranged in parallel with the pixel electrode is further formed in the device layer 140.

The lower polarizer 160 having a predetermined optical axis is formed on the lower surface of the lower substrate 100. The lower polarizer 160 may be formed of a sheet polarizer, or may be formed of a wire grid polarizer, and the type of the lower polarizer 160 may be the optical path changing unit 500. Can be appropriately selected depending on the formation method. This will be described later.

The upper substrate 200 faces the lower substrate 100 with the liquid crystal layer 300 interposed therebetween.

A light shielding layer 220 is formed on a lower surface of the upper substrate 200 to block light leakage to a region other than the pixel region, and red (R) for realizing color is formed in the region between the light shielding layers 220. ), Green (G), and blue (B) color filter layers 240 are formed. Although not shown, a common electrode for forming an electric field together with the pixel electrode may be formed on the color filter 240. However, as described above, in the IPS mode, since the pixel electrode and the common electrode are arranged parallel to each other on the lower substrate 100 to form a transverse electric field therebetween, the color filter layer of the upper substrate 200 ( The common electrode is not formed on the 240, and an overcoat layer for planarizing the substrate may be formed instead.

Since the light blocking layer 220 formed on the upper substrate 200 is used to block light leakage from the gate line, the data line, and the thin film transistor forming region formed on the lower substrate 100, the light blocking layer The 220 may be formed in a matrix structure so as to cover the gate line, the data line, and the thin film transistor region. have.

An upper polarizer 260 may be formed on an upper surface of the upper substrate 200, and the upper polarizer 260 may be formed such that its optical axis is perpendicular to the lower polarizer 160. Like the lower polarizer 160, the upper polarizer 260 may also be formed of a sheet polarizer or a wire grid polarizer. However, the lower polarizer 160 is preferably applied by distinguishing the type of polarizer according to the method of forming the optical path changing unit 500, but the upper polarizer 260 does not need to be distinguished and applied as such. .

The backlight 400 is disposed under the lower substrate 100, more specifically, under the lower polarizer 160 formed on the lower surface of the lower substrate 100 to supply light toward the lower substrate 100. Play a role.

The backlight 400 may have various types of backlights applied thereto. That is, a light source is disposed on one side and a light guide plate for guiding the light emitted from the light source to the upper side, as well as a so-called etch-type backlight disposed to face the light source, is disposed in front of the light source to supply light upward without a separate light guide plate. Both direct type backlights are applicable. In addition, various light sources known in the art may be used as a light source, such as a cold cathode fluorescent lamp (CCFL), a light emitting diode (LED), or a flat fluorescent lamp (FFL).

In addition, the backlight 400 may further include an optical film such as a diffusion sheet and a prism sheet for uniformly supplying the light emitted from the light source toward the lower substrate 100.

The optical path changing unit 500 changes the path of the light emitted from the backlight 400 to increase the amount of light supplied to the upper substrate 100. More specifically, the light path changing unit 500 changes the path of the light emitted from the backlight 400 to increase the amount of light supplied to the area between the light blocking layers 220 of the upper substrate 100. .

The optical path changing unit 500 is formed between the lower substrate 100 and the backlight 400, more specifically, between the lower polarizer 160 and the backlight 400.

The light emitted from the backlight 400 may be lost by various causes while passing through the lower substrate 100, the liquid crystal layer 300, and the upper substrate 100, in particular, the lower polarizer 160. And while passing through the upper polarizing plate 260, a considerable amount of light is absorbed and lost by the lower polarizing plate 160 and the upper polarizing plate 260.

Therefore, when the optical path changing unit 500 is formed between the lower substrate 100 and the lower polarizer 160, since the light path has already been lost while a considerable amount of light has passed through the lower polarizer 160, the optical path has changed. It is impossible to maximize the effect of increasing the amount of light to be obtained through the changing unit 500, and for this reason, the light path changing unit 500 according to the present invention is formed under the lower polarizing plate 160.

The optical path changing unit 500 changes the path of the light emitted from the backlight 400 to increase the amount of light supplied to the area between the light blocking layers 220 of the upper substrate 200. In the same manner, the backlight 400 may be configured to reflect light emitted from the backlight 400, and in some cases, may be configured to refract the light emitted from the backlight 400. This will be described in detail below.

As described above, since a considerable amount of light is blocked by the light blocking layer 220 formed on the upper substrate 100, the light is emitted from the backlight 400 to a region corresponding to the light blocking layer 220. The incoming light does not contribute to displaying the image and is lost.

Therefore, the light path changing unit 500 should change the path of light entering the area corresponding to the light blocking layer 220, and the light whose path is changed by the light path changing unit 500 is the light blocking layer. It should be directed to the area between 220.

In consideration of the above, the light path changing unit 500 should be formed in a pattern for changing the path of light entering the area corresponding to the light blocking layer 220, and in the light path changing unit 500. As a pattern for changing the path of the light, a pattern for refracting incident light into a region between the light blocking layers 220 or a pattern for reflecting and recycling the incident light may be used.

When the light path changing unit 500 uses a pattern for refracting incident light into a region between the light blocking layers 220, only the light path changing unit 500 may be configured to obtain a desired light transmittance enhancement effect. . In this case, the optical path changing unit 500 may use various refractive patterns known in the art.

When the pattern reflecting the incident light is used as the optical path changing unit 500, an additional configuration for re-reflecting the light reflected by the optical path changing unit 500 to guide the lower substrate 100 may be used. Required. In this case, the light path changing unit 500 may use a metal material such as white resin or aluminum as a reflective pattern.

The light guide part 550 is to guide the light reflected by the light path changing part 500 back to the upper substrate 100. Therefore, the light guide part 550 is made of a light reflective material. The light guide part 550 is positioned below the backlight 400, specifically, below the light source of the backlight 400. If the light induction part 550 made of the light reflection material is positioned above the light source of the backlight 400, the light emitted from the light source of the backlight 400 may not be uniformly supplied toward the lower substrate 100. Because.

On the other hand, the backlight 400 itself may include a reflector for reflecting light in the lower portion of the light source in order to minimize the loss of light emitted from the light source, in this case, the reflector included in the backlight 400 is the light guide unit ( 550, so there is no need to configure a separate light guide portion 550.

As described above, since the light path changing unit 500 needs to change the path of the light supplied to the area corresponding to the light blocking layer 220, the light path changing unit 500 may be formed in a pattern corresponding to the light blocking layer 220. On the other hand, since the light blocking layer 220 formed on the upper substrate 200 is intended to block light leakage to the gate line, data line, and thin film transistor regions formed on the lower substrate 100, the light blocking layer ( 220 is changed according to the pattern of the gate line, the data line, and the thin film transistor.

As a result, the light path changing unit 500 may include a pattern corresponding to the light blocking layer 220 formed on the upper substrate 200 or a gate line, a data line, and a thin film transistor formed on the lower substrate 100. The pattern may be formed in a corresponding pattern. Hereinafter, a specific pattern of the optical path changing unit 500 will be described.

3A is a schematic layout of the lower substrate 100, and FIG. 3B is a schematic layout of the upper substrate 200.

As can be seen in FIG. 3A, the lower substrate 100 includes an active area (A / A) for displaying an image and a dummy area (D / A) outside the active area (A / A). It is done by

The gate line 120a is arranged in the horizontal direction in the active region A / A, the data line 120b is arranged in the vertical direction, and the gate line 120a and the data line 120b cross each other. In the region, the thin film transistor T connected to the gate line 120a and the data line 120b is formed.

As such, the configuration of the gate line 120a, the data line 120b, and the thin film transistor T may be changed in various forms known in the art. For example, the thin film transistor T may be formed to overlap the gate line 120a, and the data line 120b may be formed in a curved straight line instead of a straight straight line.

Although not shown, various pads are formed in the dummy area D / A. In addition, the pads should be able to be exposed to the outside in the liquid crystal display because a signal must be applied from the outside. In general, since the pads are formed only on the lower substrate 100 and are not formed on the upper substrate 200, the dummy region D / A has a larger lower substrate 100 than the upper substrate 200. Therefore, the size of the lower substrate 100 is larger than that of the upper substrate 200.

As shown in FIG. 3B, the upper substrate 200 also includes an active area (A / A) for displaying an image and a dummy area (D / A) outside the active area (A / A). It is done by However, as described above, the dummy region D / A of the upper substrate 100 is smaller than the dummy region D / A of the lower substrate 100.

The light blocking layer 220 is formed on the upper substrate 200 in a matrix structure.

The light blocking layer 220 is formed to cover the gate line 120a, the data line 120b, and the thin film transistor T region of the lower substrate 200 in the active region A / A. In consideration of a margin, the gate line 120a, the data line 120b, and the thin film transistor T are formed to have a size slightly larger than that of the region. The light blocking layer 220 is also formed in the entire dummy area D / A.

The pattern of the optical path changing unit 500 according to the present invention designed in consideration of the lower substrate 100 and the upper substrate 200 described above is the same as that of FIGS. 4A and 4B.

4A illustrates a pattern of the optical path changing unit 500 according to an exemplary embodiment of the present invention. The optical path changing unit 500 is formed in consideration of the lower substrate 100.

As can be seen in FIG. 4A, the pattern of the optical path changing unit 500 includes the entire dummy region D / A of the lower substrate 100 and a gate line in the active region A / A of the lower substrate 100. It may be formed in a pattern corresponding to the 120a, the data line 120b, and the thin film transistor T.

4B illustrates a pattern of the optical path changing unit 500 according to another embodiment of the present invention, which is formed by considering the configuration of the upper substrate 100.

As shown in FIG. 4B, the pattern of the light path changing unit 500 may be formed in a pattern corresponding to the light blocking layer 220 of the upper substrate 200.

The optical path changing unit 500 described above may be directly patterned on the lower polarizer 160.

That is, various methods such as screen printing, roll printing, and imprinting the light path changing unit 500 pattern according to FIG. 4A or 4B are performed on the lower surface of the lower polarizer 160. It can be formed by the printing process of.

However, when the optical path changing unit 500 pattern is directly formed on the lower surface of the lower polarizing plate 160 using the printing process, the lower polarizing plate 160 should be made of a material suitable for the printing process. When the polarizing plate having a sheet structure is used as the lower polarizing plate 160, the lower polarizing plate 160 may be damaged by the printing process. Therefore, when the optical path changing unit 500 pattern is directly formed on the lower surface of the lower polarizing plate 160 using the printing process as described above, the lower polarizing plate 160 may include a polarizing plate having a wire grid structure. It is preferable to use a polarizing plate which is not damaged during the same printing process.

Meanwhile, the sheet structure having the light path changing unit 500 pattern of FIG. 4A or 4B may be used without directly forming the light path changing unit 500 pattern on the lower surface of the lower polarizing plate 160. .

As such, when the optical path changing unit 500 is formed as a sheet structure, the sheet structure may be attached onto the lower surface of the lower polarizing plate 160. Accordingly, the lower polarizing plate 160 may also form a polarizing plate having a sheet structure. It is enough to use.

1 is a schematic cross-sectional view of a conventional liquid crystal display device.

2 is a schematic cross-sectional view of a liquid crystal display according to an exemplary embodiment of the present invention.

3A is a schematic layout of a lower substrate according to an embodiment of the present invention, and FIG. 3B is a schematic layout of an upper substrate according to an embodiment of the present invention.

4A illustrates a pattern of an optical path changing unit according to an embodiment of the present invention, and FIG. 4B illustrates a pattern of an optical path changing unit according to another embodiment of the present invention.

<Description of the code | symbol about the structure of the principal part of drawing>

100: lower substrate 160: lower polarizing plate

200: upper substrate 220: light shielding layer

300: liquid crystal layer 400: backlight

500: light path changing unit 550: light guide unit

Claims (10)

An upper substrate and a lower substrate facing each other; A liquid crystal layer formed between the upper substrate and the lower substrate; A lower polarizer formed on a lower surface of the lower substrate; A backlight formed under the lower polarizer; And And an optical path changing unit formed between the lower polarizing plate and the backlight to increase the amount of light supplied to the upper substrate by changing a path of light emitted from the backlight. The method of claim 1, The optical path changing unit may be formed of a refractive pattern for increasing the amount of light supplied to the areas between the light blocking layers by refracting light emitted from the backlight and entering a region corresponding to the light blocking layer formed on the upper substrate. Liquid crystal display device. The method of claim 1, The light path changing unit is formed of a reflective pattern for increasing the amount of light supplied to the area between the light shielding layer by reflecting the light emitted from the backlight and entering the area corresponding to the light shielding layer formed on the upper substrate. Liquid crystal display device. The method of claim 3, wherein And guide the light reflected by the light path changing unit toward the upper substrate, but further comprising a light inducing unit. 5. The method of claim 4, And the light inducing part is formed of a light reflecting material positioned under the light source of the backlight. The method of claim 1, And the optical path changing unit is formed in a pattern corresponding to a gate line, a data line, and a thin film transistor formed in the entire dummy region and the active region on the lower substrate. The method of claim 1, And the light path changing unit is formed in a pattern corresponding to the light blocking layer formed on the upper substrate. The method of claim 1, The optical path changing unit is a liquid crystal display, characterized in that the pattern formed directly on the lower surface of the lower polarizing plate through a printing process. The method of claim 8, The lower polarizer is a liquid crystal display, characterized in that consisting of a polarizing plate of a wire grid structure. The method of claim 1, And the light path changing unit is formed of a sheet structure having a predetermined pattern, and the sheet structure is attached to a lower surface of the lower polarizing plate.

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