KR20110007287A

KR20110007287A - Liquid crystal display device for privacy protection

Info

Publication number: KR20110007287A
Application number: KR1020090064733A
Authority: KR
Inventors: 이승희; 전은정; 임영진; 김진호; 허정화
Original assignee: 전북대학교산학협력단
Priority date: 2009-07-16
Filing date: 2009-07-16
Publication date: 2011-01-24

Abstract

PURPOSE: A liquid crystal display device for protecting privacy is provided to reduce the manufacturing cost, and simplify the manufacturing process. CONSTITUTION: A liquid crystal layer(14) is located at the lower part of an upper plate. A lower plate(13) is located at the lower part of the liquid crystal layer. A lower polarizing plate(12) is placed at the lower part of the lower plate. The liquid crystal layer is driven with perpendicularity or the horizontal electrical field.

Description

Liquid Crystal Display Device for Privacy Protection

The present invention relates to a liquid crystal display device for privacy protection without a polarizing plate on the top, and relates to a method using a liquid crystal display device and a polarizing sunglasses except the upper polarizing plate attachment process in the existing process. The present invention relates to a liquid crystal display device that allows a user to not show information that requires personal or security to others when using the liquid crystal display device in a public place.

Recently, as liquid crystal displays are applied to mobile technologies such as laptops, cellular phones, and other portable displays, the use of liquid crystal displays is increasing not only indoors but also outdoors. This has caused a new problem that information, which must be kept private or secure, can be leaked to others through portable LCDs in public places. In order to protect the information expressed through the liquid crystal display from others, a liquid crystal display technology having a narrow viewing angle feature and a liquid crystal display device capable of adjusting the viewing angle have been developed.

In the case of a liquid crystal display device having a narrow viewing angle characteristic, the information expressed through the liquid crystal display device has a merit of protecting privacy because the information is not visible in the out-of-front viewing angle direction, but has a narrow viewing angle range. Even if the information is expressed in the viewing angle range, it is difficult to expect perfect privacy protection because the information is easily exposed to others located behind the user. The liquid crystal display device capable of adjusting the viewing angle has a great advantage in adjusting the viewing angle range that can selectively display information as needed, but has a disadvantage in that the price competitiveness is inferior due to the need for additional panels or processes.

The present invention is to solve the above problems, and unlike the conventional technology that the viewing angle range for viewing personal information from the liquid crystal display is fixed to the front or selectively adjusted, the upper polarizing plate included in the liquid crystal display Except for the above, the purpose of the present invention is to provide a liquid crystal display device in which only the user recognizes the information and provides complete privacy through the polarized sunglasses instead of the upper polarizer.

In order to achieve the above object, the present invention provides a liquid crystal display device capable of privacy protection using one liquid crystal display device and one polarized sunglasses except for the upper polarizing plate. The polarized sunglasses have a constant transmission axis to replace the upper polarizing plate, and are positioned perpendicular to the transmission axis of the lower polarizing plate included in the liquid crystal display. Since the liquid crystal moves along the electric field between the lower polarizer and the polarized sunglasses where the transmission axis is perpendicular to each other to express information, others who do not wear polarized sunglasses cannot create a dark state regardless of the electric field. The low contrast ratio makes the information unrecognizable.

In the present invention, since the upper polarizer is not required, the manufacturing cost is reduced, and the manufacturing process is simpler than that of the conventional viewing angle control liquid crystal display device.

In addition, the present invention enables the manufacture of a liquid crystal display device that can completely protect the privacy not only in the left and right directions, but also in the top, bottom and back.

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

Example

The embodiment is made up of a liquid crystal display device for privacy protection, which consists of one liquid crystal display device and one polarized sunglass except for the upper polarizing plate, so that only a user wearing sunglasses can recognize information.

1 is a cross-sectional view for describing a privacy protection liquid crystal display device according to an exemplary embodiment of the present invention. As illustrated, the privacy protection liquid crystal display device of the present invention includes a light source 11, a lower polarizing plate 12, a lower substrate 13, a liquid crystal layer 14, and an upper substrate 15. The lower polarizer 12 is positioned, and the lower substrate 13 made of glass or plastic is positioned on the lower polarizer 12. The liquid crystal layer 14 is positioned on the lower substrate 13, and the upper substrate 15 made of glass or plastic is positioned on the liquid crystal layer 14. Therefore, only the observer 100 wearing the polarized sunglasses 16 may recognize the information.

The transmission axis of the polarized sunglasses 16 and the transmission axis of the lower polarizing plate 12 are proposed to be perpendicular to each other.

The liquid crystal layer 14 is arranged in a vertical, horizontal or twisted manner and is driven by a vertical or horizontal electric field.

FIG. 2 shows a polarization state according to whether voltage is applied in the privacy protection liquid crystal display device having the polarized sunglasses 16. In order to recognize the information, the transmission axis of the polarizing sunglasses 16 should be perpendicular to the transmission axis of the lower polarizing plate 12. FIG. 2A is a privacy protection liquid crystal display device in which no voltage is applied, and the unpolarized light emitted from the light source 11 vibrates in the transmission axis direction of the lower polarizing plate 12 when it passes through the lower polarizing plate 12. Linearly polarized light 17, and the linearly polarized light 17 passes through the liquid crystal layer 14 without change in polarization state, and thus does not coincide with the transmission axis of the polarized sunglasses 16 so that light does not pass. It does not appear dark. 2 (b) shows a privacy protection liquid crystal display when a voltage is applied. When a voltage is applied, an electric field is formed and the liquid crystal behaves by the formed electric field, thereby changing the phase delay value of the liquid crystal layer 14. Thus, when the unpolarized light emitted from the light source 11 passes through the lower polarizing plate 12, it becomes a linearly polarized light 17 vibrating in the transmission axis direction of the lower polarizing plate 12, and the linearly polarized light 17 is caused by an electric field. When the phase delay changes through the liquid crystal layer 14, the linearly polarized light 18 oscillating in a direction coinciding with the transmission axis of the polarized sunglasses 16 passes through the polarized sunglasses 16 to indicate a bright state. Therefore, since the dark state and the bright state may be displayed according to the application of voltage, only the user wearing the polarized sunglasses 16 may obtain a high contrast ratio and recognize the information.

3 illustrates a polarization state depending on whether a voltage is applied in the liquid crystal display without the upper polarizer. In the case of a user who does not wear polarized sunglasses, Fig. 3 (a) is a state before voltage is applied, and when the unpolarized light emitted from the light source 11 passes through the lower polarizing plate 12, it is directed to the transmission axis direction of the lower polarizing plate 12. It becomes a vibrating linearly polarized light 17 and the linearly polarized light 17 passes through it as it is without phase change in the liquid crystal layer 14, thereby exhibiting a bright state. 3 (b) shows a case where voltage is applied, the linearly polarized light 17 vibrating in the transmission axis direction of the lower polarizer 12 when unpolarized light from the light source 11 passes through the lower polarizer 12. When the linearly polarized light 17 passes through the liquid crystal layer 14 in which the phase retardation is changed by the electric field, the linearly polarized light 17 becomes a linearly polarized light 18 that vibrates in a direction coinciding with the transmission axis of the polarized sunglasses. However, since the polarized sunglasses do not exist on the top, even if the polarization state of the light is changed, the light passes through as it is, regardless of whether or not the voltage is applied. As a result, the contrast ratio becomes 1, making it impossible to recognize information.

4 illustrates information recognized by a user wearing the polarized sunglasses 16 in the case of FIG. 2. As illustrated in FIG. 2, a user wearing polarized sunglasses may recognize information in any direction as shown in FIG. 5.

FIG. 5 shows information recognized by a user who does not wear the polarized sunglasses 16 in the case of FIG. 3. As described with reference to FIG. 3, a user who does not wear polarized sunglasses can pass light as it is, regardless of whether voltage is applied, and the contrast ratio is 1, and as shown in FIG. 5, information cannot be recognized in any direction.

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

2 is a liquid crystal display device having polarized sunglasses.

3 is a liquid crystal display without the upper polarizer.

4 is a representation of information in the front and viewing angle directions according to FIG. 2;

5 is a representation of information in the front and viewing angle directions according to FIG. 3;

Claims

In the liquid crystal display device without the upper polarizing plate,

An upper substrate;

A liquid crystal layer disposed under the upper substrate;

A lower substrate positioned below the liquid crystal layer;

Is composed of a lower polarizing plate positioned below the lower substrate,

A privacy protection liquid crystal display that allows only users wearing polarized sunglasses to recognize information from the liquid crystal display without the upper polarizer.

The method of claim 1,

Privacy liquid crystal display device characterized in that the liquid crystal layer is arranged in a vertical, horizontal or twisted

The method of claim 1,

Privacy liquid crystal display device characterized in that the liquid crystal layer is driven by a vertical or horizontal electric field