KR101708855B1 - Liquid Crystal Display Device - Google Patents

Abstract

The present invention relates to a liquid crystal cell comprising a lower substrate, an upper substrate, and a liquid crystal layer formed between the lower substrate and the upper substrate; And a multi-layer structure formed on one surface of the liquid crystal cell, the multi-layer structure including a first laminate having a predetermined refractive index and a second laminate having a refractive index different from the refractive index of the first laminate, And water. The liquid crystal display device according to claim 1,

According to the present invention, even when the power of the liquid crystal display device is turned off by applying a multi-layered structure in which first and second stacks having different refractive indexes are laminated, the reflection wavelength of external light is appropriately adjusted, The image can be displayed as it is in the front direction when the image is displayed and the specific color can be displayed in the left and right side directions so that the image can not be seen so that it can be usefully used for liquid crystal display devices for information protection purposes .

Multi-layered structure, oxide

Description

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

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 suitable for use in a specific use such as an application for protecting information from a person in a side seat in a moving means.

Liquid crystal display devices have a wide range of applications ranging from mobile phones, notebook computers, monitors, spacecrafts and aircraft to the advantage of low operating voltage and low power consumption and being portable.

The liquid crystal display device includes a lower substrate, an upper substrate, and a liquid crystal layer formed between the two substrates. The arrangement of the liquid crystal layers is adjusted according to whether an electric field is applied or not, .

Meanwhile, in recent years, a liquid crystal display device to which a specific function has been added to meet various demands of a consumer has been developed.

For example, in a liquid crystal display device applied to a mobile phone or the like, a specific color can be displayed while the power is off. That is, in general, black color is displayed when the power of the liquid crystal display device is off. However, in the case of a cell phone targeting a younger consumer, in the state where the power is off, A liquid crystal display device has been developed.

In a conventional liquid crystal display device in which a specific color is displayed in a state that the power is off, a separate cell including a cholesteric liquid crystal is additionally provided so that external light is transmitted through the cholesteric liquid crystal And is designed to selectively reflect light of a specific wavelength.

However, it is difficult to implement various colors in a conventional liquid crystal display device in which a separate cell including the cholesteric liquid crystal is added. In the front view, a desired specific color is displayed well, but color variation becomes severe depending on a viewing angle, There is a disadvantage in that a desired specific color is not displayed well. In addition, a separate cell including a cholesteric liquid crystal is added, which leads to an increase in cost and a complicated manufacturing process.

In addition, when a notebook or a mobile phone is used in a moving means such as a train or an airplane, a liquid crystal display device whose viewing angle is adjusted in order to protect information from a person in a side seat is being developed. In other words, although a liquid crystal display device for realizing a wide viewing angle has been developed so that an image can be viewed not only on the front but also on the left and right sides, recently, in order to protect the privacy, the image can not be seen on the left and right sides, A liquid crystal display device has been developed.

In the conventional liquid crystal display device having the function of allowing the image to be viewed only on the front surface as described above, the ECB (Electronically Controlled Birefringence) mode is additionally provided in the pixel together with the existing mode so that the viewing angle is adjusted It is designed to be able to view images only from the front.

However, in the conventional liquid crystal display device to which the ECB mode is added, when the ECB mode is operated, there is a monotonous problem that the colors shown on the left and right sides are limited to only the white color, and the cost is increased due to addition of the ECB mode There are disadvantages.

As described above, in recent years, a liquid crystal display device having a specific function has been developed to meet various demands of a consumer. However, in the case of a conventional method in which a separate cell including a cholesteric liquid crystal or an ECB mode is additionally constructed There is a disadvantage in that the cost is increased, and there is also a problem in efficiently implementing a desired function in each application.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the prior art, and it is an object of the present invention to provide a liquid crystal display device having a specific function, in which a separate cell including a cholesteric liquid crystal or an ECB mode And it is an object of the present invention to provide a liquid crystal display device capable of effectively realizing a specific function desired.

In order to achieve the above object, the present invention provides a liquid crystal cell comprising a lower substrate, an upper substrate, and a liquid crystal layer formed between the lower substrate and the upper substrate; And a multi-layer structure formed on one surface of the liquid crystal cell, the multi-layer structure including a first laminate having a predetermined refractive index and a second laminate having a refractive index different from the refractive index of the first laminate, And water. The liquid crystal display device according to claim 1,

Each of the first laminate and the second laminate may be made of a transparent oxide. In particular, the first laminate may be made of TiO ₂ , and the second laminate may be made of SiO ₂ .

The multi-layer structure may be formed by alternately laminating the first laminate and the second laminate. In this case, the thickness of each of the first laminate and the second laminate is in the range of 10 to 800 nm, and the total number of laminated layers of the first laminate and the second laminate may range from 2 to 50 layers.

The multi-layer structure may be formed on the liquid crystal cell. At this time, an upper polarizer is formed on the liquid crystal cell, and the multilayer structure may be formed between the liquid crystal cell and the upper polarizer, or may be formed on the upper polarizer. When the multilayer structure is formed on the upper polarizer, the multilayer structure may be formed on a substrate made of glass or transparent plastic, and the substrate may be formed on the upper polarizer.

Wherein the liquid crystal cell comprises a first pixel and a second pixel having different modes from each other, the first pixel includes a pixel electrode formed on the lower substrate to form a vertical electric field, and a common electrode formed on the upper substrate And the second pixel includes a pixel electrode and a common electrode formed on the lower substrate to form a horizontal electric field or a fringe field.

According to the present invention as described above, the following effects can be obtained.

According to the present invention, even when the power source of the liquid crystal display is turned off by applying a multi-layered structure in which first and second layers having different refractive indexes are laminated, the reflection wavelength of external light is appropriately adjusted, The color of the area can be displayed.

In addition, the present invention can appropriately adjust the reflection wavelength of external light by applying a multi-layered structure in which first and second laminated layers having different refractive indexes are different from each other, so that when the image is displayed, And a specific color is displayed in the side direction so that an image can not be seen, so that it can be usefully used in a liquid crystal display device for information protection use.

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

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

1, the liquid crystal display according to an exemplary embodiment of the present invention includes a liquid crystal cell 100, an upper polarizer 200, a lower polarizer 250, and a multi-layer structure 300.

The liquid crystal cell 100 includes a lower substrate 10, an upper substrate 30 and a liquid crystal layer 50 formed between the lower substrate 10 and the upper substrate 30. The liquid crystal cell 100 may be formed in various forms, which will be described later.

The upper polarizer 200 is formed on the upper surface of the liquid crystal cell 100 and has a predetermined optical axis to transmit only light of a specific optical axis.

The lower polarizer 250 is formed on the lower surface of the liquid crystal cell 100 and has a predetermined optical axis to transmit only light of a specific optical axis.

The optical axis of the upper polarizer 200 and the lower polarizer 250 are orthogonal to each other so that the transmittance of light can be controlled as the alignment of the liquid crystal layer 50 of the liquid crystal cell 100 is changed have.

The multi-layer structure 300 is formed on the upper surface of the upper polarizer 200.

As shown in the enlarged view of FIG. 1, the multi-layer structure 300 may be formed by alternately stacking the first stack 320 and the second stack 330 on the substrate 310. That is, a first laminate 320 and a second laminate 330 are alternately laminated on a substrate 310 made of glass or transparent plastic, and then the substrate 310 is laminated on the upper polarizer 200 Can be attached. However, the present invention is not limited thereto. Alternatively, the first laminate 320 and the second laminate 330 may be directly alternately stacked on the upper surface of the upper polarizer 200 without using the substrate 310, The multi-layer structure 300 may be constructed.

The multi-layer structure 300 is applied to perform a specific function in the liquid crystal display device.

For example, when the liquid crystal display device according to the present invention is applied to a cellular phone or the like so that a specific color can be displayed while the power is off, the multilayered structure 300 reflects external light So that a specific color can be displayed. This will be described in detail as follows.

As shown in FIG. 2, the multi-layer structure 300 includes the first laminate 320 and the second laminate 330. At this time, the first laminate 320 and the second laminate 330 are made of materials having different refractive indices, and the first laminate 320 and the second laminate 330 having different refractive indices are different from each other, Are stacked alternately to constitute the multi-layer structure (300).

When the external light is incident on the multi-layer structure 300 at a predetermined incident angle, the external light is reflected inside the multi-layer structure 300. At this time, the reflection wave length of the reflected light reflected inside the multi-layer structure 300 is expressed by the following Equation 1:

[Formula 1]

Where m denotes the total number of laminated layers of the first laminate 320 and the second laminate 330, and p denotes a total number of laminated layers of the first laminate 320 and the second laminate 330, Means the sum of the thickness d1 of the laminate 320 and the thickness d2 of the second laminate 330. [

는 하기 식2와 같이 표시된다. In the above formula 1,

Is expressed by the following equation (2).

[Formula 2]

In Equation 2, n ₁ is a refractive index of the first laminate 320, and n ₂ is a refractive index of the second laminate 330.

As can be seen from Equations 1 and 2, the reflected wavelength λ of the reflected light depends on the thickness d1 of the first laminate 320, the thickness d2 of the second laminate 330, The refractive index n ₁ of the first laminate 320 and the refractive index n 2 of the second laminate 330 and the refractive index n ₂ of the first laminate 320 and the second laminate 330, As shown in FIG.

Accordingly, the first laminate 320 having the predetermined refractive index n ₁ and the second laminate 330 having the predetermined refractive index n ₂ are appropriately selected and the refractive indices of the first laminate 320 It is possible to obtain a desired reflection wavelength λ of the reflected light when the thickness d1 and the thickness d2 of the second laminate 330 are appropriately adjusted and stacked in a predetermined number of layers, It is possible to display a desired specific color even when it is off.

Considering these points, the first laminate 320 and the second laminate 330 may be made of a transparent oxide. In particular, TiO ₂ may be used as the first laminate 320, SiO ₂ can be used as the second laminate 330. When the multi-layer structure 300 is formed of such a transparent oxide, it is easily formed at a pressure of 10 ^-3 to 10 ^-5 Torr and a temperature range of 20 to 80 ° C through an e-beam or a sputter .

When the first laminate 320 and the second laminate 330 are alternately stacked, the thicknesses of the first laminate 320 and the second laminate 330 are preferably 10 to 800 nm, , And the total number of stacked layers of the first laminate 320 and the second laminate 330 may be in the range of 2 to 50 layers.

As described above, when the multilayer structure 300 is formed by alternately laminating the first laminate 320 and the second laminate 330, when the power of the liquid crystal display device is turned off, Specific colors, for example, colors such as blue, gold, pink, and green, which are applied to the exterior case of a mobile phone, may be displayed.

FIG. 3 is a graph illustrating a result of experiments on colors displayed when the power is turned off in a liquid crystal display device to which various multilayer structures 300 according to the present invention are applied.

In the experiment according to FIG. 3, the multi-layer structure 300 is formed by alternately laminating a first laminate 320 using TiO ₂ and a second laminate 330 using SiO ₂ .

3, when the total stacking number of the first laminate 320 and the second laminate 330 is set to 26 and the total thickness is set to 1.57 mu m, I can confirm that it is displayed. In addition, it was confirmed that when the total stacking number of the first stacked body 320 and the second stacked body 330 was 18 and the total thickness was 1.64 탆, the gold color of the liquid crystal display device was displayed when the power was off , And when the total stacking number of the first laminate 320 and the second laminate 330 is set to 21 layers and the total thickness is set to 1.64 탆, a pink color is displayed when the power of the liquid crystal display device is turned off there was.

On the other hand, as another example, when the liquid crystal display device according to the present invention is used for protecting information from a person in a side seat in the moving means, the multilayered structure 300 can not see images on the left and right sides, So that the user can see the image.

The reflection wavelength λ of the reflected light can be determined by the thickness d1 of the first laminate 320 and the thickness d2 of the second laminate 330. As shown in Equation 1, At this time, the total thickness of the multi-layer structure 300 in the front direction and the total thickness of the multi-layer structure 300 in the left and right direction are different from each other.

Accordingly, when the multilayer structure 300 is formed by appropriately laminating the first laminate 320 and the second laminate 330, colors displayed in the front direction and colors displayed in the left and right side directions are different from each other . In other words, the multilayer structure 300 may be formed so that the colors displayed in the front direction are white and the colors displayed in the left and right directions are specific colors. In this case, in the front direction, The image to be implemented in the liquid crystal cell 100 can not be displayed due to the specific color displayed in the multilayer structure 300 in the left and right side directions, It can be used for applications.

When the liquid crystal display device is used for information protection, when the multilayer structure 300 is formed by alternately laminating the first laminate 320 and the second laminate 330, 1 laminate 320 and the second laminate 330 are laminated in the range of 10 to 800 nm and the total number of laminated layers of the first laminate 320 and the second laminate 330 is 2 To 50 layers.

FIG. 4 is a graph showing an experiment result in which a color display varies depending on a viewing angle in a liquid crystal display device to which the multilayer structure 300 according to the present invention is applied.

4, the multi-layer structure 300 is formed by alternately laminating a first laminate 320 using TiO ₂ and a second laminate 330 using SiO ₂ , The total number of layers of the second laminate 320 and the second laminate 330 was set to 34 and the total thickness was set to 0.45 μm.

As can be seen from FIG. 4, a white color is displayed on the front side, but a specific color, for example, cyan, is displayed on the left and right sides. When the multi-layered structure 300 as described above is applied, So that the information for protecting the information from the person in the next seat can be easily utilized.

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

The liquid crystal display according to another embodiment of the present invention shown in FIG. 5 is the same as the liquid crystal display according to FIG. 1 except that the formation position of the multilayer structure 300 is changed. Therefore, the same reference numerals are assigned to the same components, and a detailed description of the same components will be omitted.

1, the multi-layer structure 300 is formed on the upper surface of the upper polarizer 200. However, in the liquid crystal display device of FIG. 5, the multi-layer structure 300 includes the upper polarizer 200 and the liquid crystal cell 100).

5, the multilayer structure 300 is more easily formed by stacking the first laminate 320 and the second laminate 330 on the upper surface of the upper substrate 30 constituting the liquid crystal cell 100 There is an advantage that it can be formed.

In addition, when the liquid crystal display device according to the present invention is applied to a mobile phone or the like and is used for displaying a specific color in a state where the power is off, it is advantageous that the color shift change according to the viewing angle is small. The liquid crystal display device according to FIG. 5 may be more preferable than the liquid crystal display device according to FIG. 1 described above.

5 in which a multilayer structure 300 is formed between an upper polarizer 200 and a liquid crystal cell 100 is shown in FIG. 1 in which a multilayer structure 300 is formed on the upper surface of the upper polarizer 200 There is an advantage in that the color shift is small compared with the liquid crystal display according to the related art.

FIG. 6A is a graph showing a change in color shift according to the viewing angle of the liquid crystal display device according to the present invention shown in FIG. 1, FIG. 6B is a graph showing a change in color shift according to the viewing angle of the liquid crystal display device according to the present invention shown in FIG. to be.

As shown in FIG. 6A, the liquid crystal display according to FIG. 1, in which the multilayer structure 300 is formed on the upper surface of the upper polarizer 200, has a slight shift in color shift depending on the viewing angle, 5 that the multi-layer structure 300 is formed between the upper polarizer 200 and the liquid crystal cell 100, the color shift due to the viewing angle is reduced.

7A to 7D are schematic cross-sectional views of a liquid crystal cell 100 according to various embodiments of the present invention. 7A to 7D, the liquid crystal cell 100 includes a lower substrate 10, an upper substrate 30, and a liquid crystal layer 50 formed between the lower substrate 10 and the upper substrate 30 . 7A to 7D show only electrodes 60 and 80 for adjusting the alignment of the liquid crystal layer 50 in the liquid crystal cell 100. A thin film transistor is formed on the lower substrate 10 as a switching element On the upper substrate 30, a light shielding layer for preventing light leakage and a color filter layer for color rendering are formed. Hereinafter, each will be described.

7A, the liquid crystal cell 100 includes a pixel electrode 60 formed on the lower substrate 10, a common electrode 80 formed on the upper substrate 30, 60 and the common electrode 80 by adjusting the alignment state of the liquid crystal layer 50 through a vertical electric field between the liquid crystal layer 60 and the common electrode 80. The liquid crystal cell 100 according to FIG. 7A corresponds to a TN (Twisted Nematic) mode, a VA (Vertical Alignment) mode, and the like.

7B, the liquid crystal cell 100 includes the pixel electrode 60 and the common electrode 80 alternately arranged in parallel to each other on the lower substrate 10, And may be configured to display an image by adjusting the arrangement state of the liquid crystal layer (50) through a horizontal electric field between the electrodes (80). The liquid crystal cell 100 according to FIG. 7B corresponds to a so-called IPS (In-Plane Switching) mode.

7C, the liquid crystal cell 100 includes a pixel electrode 60 and a common electrode 80 arranged on the lower substrate 10 with an insulating layer 70 therebetween, and the pixel electrode 60 And the fringe field between the common electrode 80 and the common electrode 80 to adjust the alignment of the liquid crystal layer 50 to display an image. The liquid crystal cell 100 according to FIG. 7C corresponds to a so-called FFS (Fringe Field Switching) mode.

As shown in FIG. 7D, the liquid crystal cell 100 may be configured to simultaneously include a first pixel driven by a vertical electric field and a second pixel driven by a horizontal electric field. That is, in the first pixel, the pixel electrode 60 is formed on the lower substrate 10, the common electrode 80 is formed on the upper substrate 30, and the common electrode 80 is formed on the lower substrate 10 The pixel electrode 60 and the common electrode 80 may be alternately arranged in parallel with each other.

The liquid crystal cell 100 shown in FIG. 7D has a so-called ECB (Electronically Controlled Birefringence) mode and an IPS (In-Plane Switching) mode, This is particularly useful when a display device is applied.

Although not shown, the liquid crystal cell 100 includes a pixel driven by a vertical electric field and a pixel driven by a fringe field so that a so-called ECB (Electronically Controlled Birefringence) mode and an FFS (Fringe Field Switching) In this case, it is particularly useful when the liquid crystal display device is used for protecting the information from the person in the next seat in the moving means.

7A to 7D illustrate a liquid crystal cell 100 according to an embodiment of the present invention. The liquid crystal display device according to the present invention is not limited to the above-described liquid crystal cell 100, The liquid crystal cell 100 may include a plurality of liquid crystal cells.

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

2 is a cross-sectional view of a multi-layer structure in accordance with one embodiment of the present invention.

FIG. 3 is a graph showing the results of experiments on colors displayed when the power is off in a liquid crystal display device to which various multilayer structures according to the present invention are applied.

FIG. 4 is a graph showing experimental results in which a color display varies depending on a viewing angle in a liquid crystal display device to which a multilayer structure according to the present invention is applied.

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

FIG. 6A is a graph showing a change in color shift according to the viewing angle of the liquid crystal display device according to the present invention shown in FIG. 1, FIG. 6B is a graph showing a change in color shift according to the viewing angle of the liquid crystal display device according to the present invention shown in FIG. to be.

7A to 7D are schematic cross-sectional views of a liquid crystal cell according to various embodiments of the present invention.

DESCRIPTION OF THE REFERENCE SYMBOLS

100: liquid crystal cell 200: upper polarizer plate

250: lower polarizer plate 300: multilayer structure

320: first laminate 330: second laminate

Claims (10)

A liquid crystal cell comprising a lower substrate, an upper substrate, and a liquid crystal layer disposed between the lower substrate and the upper substrate; And A multi-layer structure disposed on one surface of the liquid crystal cell, the multi-layer structure including a plurality of layers, Wherein the multilayer structure comprises a first laminate having a predetermined refractive index and a second laminate having a refractive index different from that of the first laminate, When external light incident at a predetermined incident angle? Is reflected within the multilayer structure, the reflected wavelength of the reflected light is expressed by the following Equation 1,  [Formula 1]

In Equation 1,

Is expressed by the following formula 2, [Formula 2]

Wherein the reflection wavelength is adjusted to realize a specific color. (Where m represents the total number of layers of the first laminate and the second laminate, and p represents the thickness of the first laminate and the thickness of the second laminate, 2 is a refractive index of the first laminate, and n2 is a refractive index of the second laminate. The method according to claim 1, Wherein each of the first laminate and the second laminate is made of a transparent oxide. 3. The method of claim 2, Wherein the first laminate is made of TiO ₂ , and the second laminate is made of SiO ₂ . The method according to claim 1, Wherein the multilayer structure is formed by alternately laminating the first laminate and the second laminate. 5. The method of claim 4, Wherein the thickness of each of the first laminate and the second laminate is in the range of 10 to 800 nm and the total number of laminated layers of the first laminate and the second laminate is in the range of 2 to 50 layers. The method according to claim 1, Wherein the multi-layer structure is disposed on the liquid crystal cell. The method according to claim 6, Wherein an upper polarizer is disposed on an upper portion of the liquid crystal cell, and the multilayer structure is disposed between the liquid crystal cell and the upper polarizer. delete 8. The method of claim 7, Wherein the multilayer structure is disposed on a substrate made of glass or transparent plastic, and the substrate is attached on the upper polarizer plate. The method according to claim 1, Wherein the liquid crystal cell includes a first pixel and a second pixel having different modes from each other, Wherein the first pixel includes a pixel electrode disposed on the lower substrate and a common electrode disposed on the upper substrate to form a vertical electric field, A liquid crystal display comprising a pixel electrode and a common electrode arranged on a substrate.

Images