KR20080057883A - 2D / 3D switching mode video display device - Google Patents

Abstract

The present invention relates to a liquid crystal display device, and to a 2D / 3D conversion mode image display device capable of converting a two-dimensional image and a three-dimensional image as necessary and implementing high brightness.

The present invention is characterized in that a cholesteric liquid crystal panel is configured as the switching element in configuring a 2D / 3D switching mode image display device using a liquid crystal panel as a switching element that enables switching between two and three dimensions.

By using the reflection characteristics of the cholesteric liquid crystal panel, a 2D / 3D switching mode image display device capable of realizing high luminance in both two-dimensional and three-dimensional images can be manufactured.

Description

2D / 3D switching mode video display device {2D / 3D exchanging mode Display device}

1 is a cross-sectional view schematically illustrating a configuration of a 2D / 3D switching mode image display device according to the related art.

2 is a cross-sectional view schematically showing the configuration of a conventional 2D / 3D switching mode image display device for displaying a three-dimensional image;

3 is a view for explaining the polarization characteristics of the cholesteric liquid crystal layer,

4 is a cross-sectional view schematically showing the configuration of a 2D / 3D switch mode image display device according to the present invention;

5A and 5B illustrate polarization characteristics of light in a first region and a second region of a cholesteric liquid crystal panel.

6A and 6B are views for explaining polarization characteristics of light in a first region and a second region of the cholesteric liquid crystal panel when displaying a 3D image.

<Description of the symbols for the main parts of the drawings>

200: TN liquid crystal panel 210: first substrate

212a, 212b, 212c: color filter 230, second substrate

232 pixel electrode 240 twisted nematic liquid crystal layer

242a: first polarizing plate 242b: second polarizing plate

244: phase difference film 250: cholesteric liquid crystal panel

260: reflector 262: lamp

264 light guide plate 272a, 272b cholesteric liquid crystal layer

280: first substrate 282: first electrode

284: second electrode 288: third electrode pattern

290: second substrate

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image display device, and more particularly, to a 2D / 3D switching mode image display device for high brightness.

The services to be realized for the high speed of information based on the high-speed information communication network today are the "view and listen" multi-media centering on the digital terminal which processes text, voice and video from the simple "listen and talk" service like the current telephone. It is expected to develop into a media-type service and ultimately develop into a hyper-spatial, realistic 3D stereoscopic information communication service that transcends time and space.

In general, the three-dimensional image representing the three-dimensional is achieved by the principle of stereo vision through two eyes, the parallax of two eyes, that is, binocular disparity that appears because the two eyes are about 65mm apart is the most important of the three-dimensional It can be called a factor.

In other words, each of the left and right eyes sees different two-dimensional images, and when these two images are transmitted to the brain through the retina, the brain accurately fuses each other to reproduce the depth and reality of the original three-dimensional image.

This ability is commonly referred to as stereography.

Stereoscopic image display uses the binocular parallax, and according to whether the viewer wears separate glasses, stereoscopic polarization and time division, autostereoscopic parallax-barrier, lenticular and blinding There is a lighting (blinking light) method.

Although the former can enjoy stereoscopic images, many people need to wear separate polarized glasses or liquid crystal shutter glasses, and the latter has an image splitter and a cylindrical lens array. Although the observation range is fixed to a small number of people, there is a characteristic that does not wear a separate glasses type tends to be preferred.

The spectacle stereoscopic image display device causes inconvenience and unnaturalness because the viewer must wear special glasses.

On the other hand, many studies have been conducted on the non-glasses stereoscopic image display apparatus because the observer directly observes the screen and the above-mentioned disadvantages disappear.

The Palallax-barrier method is a method of feeling stereoscopic feeling by separating and observing a stereoscopic image synthesized through the slit by placing a vertical or horizontal form (slit) in front of an image corresponding to both left and right eyes.

Meanwhile, a configuration capable of displaying both a 3D image and a 2D image using the same display device has been proposed, and for this purpose, a structure in which a liquid crystal panel is applied to the parallax-barrier has been proposed.

That is, by partially driving the liquid crystal panel to create a dark state, the image splitter effect of the Pallex-barrier can be realized to display three dimensions, and at the same time, the light is transmitted through the entire area of the liquid crystal panel. Eliminating the image split effect of the Rex-Barrier layer can realize a conventional two-dimensional image.

However, when the liquid crystal panel is used as the switching means for transversing the two-dimensional image and the three-dimensional image, additionally, a plurality of polarizing plates are added, resulting in a very low luminance of the display device.

This will be described below with reference to FIG. 1.

1 is a cross-sectional view schematically showing the configuration of a conventional 2D / 3D switch mode image display apparatus.

As illustrated, the conventional 2D / 3D switching mode image display device 20 may be divided into the light source L by the display unit D and the switching unit S. FIG.

The display unit D includes a first liquid crystal panel 30 and a first polarizing plate 38a and a second polarizing plate 38b disposed on the upper and lower portions of the first liquid crystal panel 30, and the polarizing plate axes are perpendicular to each other. Is arranged to.

The switching unit S includes a second liquid crystal panel 32 and a third polarizing plate 38c disposed under the second liquid crystal panel 32 as a switching element that converts between two-dimensional and three-dimensional images.

In the second liquid crystal panel 32, a plurality of first regions A1 and second regions A2 are alternately formed, and when a three-dimensional image is expressed, light is transmitted to the first region A1. The second area A2 blocks the light to implement the image split effect of the Palalex-barrier.

To this end, the first electrode 42a and the second electrode 42b are separately patterned on the upper and lower portions of the portion corresponding to the second area A2, and the first and second parts only when the 3D image is to be realized. The voltage is applied to the electrodes 42a and 42b to rearrange the liquid crystal 46 corresponding thereto, thereby preventing light from passing through.

In this case, the second polarizing plate 38b and the third polarizing plate 38c are disposed such that the polarization axes are parallel to each other, and the first polarizing plate 38a is a direction in which the polarization axes are perpendicular to the second and third polarizing plates 38b and 38c. It is arranged to be.

In addition, the liquid crystal layer 44 filled in the second liquid crystal panel 32 has a horizontal alignment state in which the optical axis is parallel to the second and third polarizing plates 38b and 38c, and is vertically arranged when a voltage is applied. Have

Therefore, when light is initially radiated from the lower light L source to the third polarizing plate 38c, the third polarizing plate 38c, the second liquid crystal panel 32, and the second polarizing plate 38b are removed. It passes through and reaches the 1st liquid crystal panel 30 which is the said display element.

The light is observed as an image through the liquid crystal panel according to the operation of the liquid crystal panel. At this time, the observed image is a two-dimensional image.

On the other hand, when the second liquid crystal panel 32 is driven by applying voltage, the PALEX-Bairer image split effect is displayed to implement the 3D image.

This will be described below with reference to FIG. 2.

As illustrated, when the voltage is applied to the first and second electrodes 42a and 42b patterned up and down corresponding to the second area A2 of the second liquid crystal panel 32 as the switching element, Only the liquid crystal layer 46b corresponding to the two regions A2 is vertically arrayed, and the liquid crystal layer 46a corresponding to the remaining first region A1 maintains its original state.

Accordingly, the light emitted from the light source L passes through the first area A1 as described above with reference to FIG. 1, but is blocked by the liquid crystal layer 46b in the second area A2.

That is, since the second region A2 acts as a barrier through which light cannot pass and the first region A1 acts as a slit through which light is transmitted, the second liquid crystal panel 32 is parallel. The image split effect of Rex Barrier enables three-dimensional image representation.

However, in the 2D / 3D switching mode image display apparatus using the liquid crystal panel as a switching means as in the prior art, the second region, that is, the region through which light is not transmitted, during the three-dimensional image representation, leads to light loss and greatly reduces the luminance. There is a problem of degrading the image quality.

In addition, since three polarizing plates are used, the light loss by each polarizing plate is also considerable, which causes a problem of lowering the luminance even more.

The present invention has been proposed to solve the above-described problem, and is characterized in that a cholesteric liquid crystal panel is used as a switching means capable of mutually switching a two-dimensional image and a three-dimensional image.

Since the cholesteric liquid crystal has a transmission and reflection characteristic for a specific circular polarized light, an object of the cholesteric liquid crystal is to manufacture a 2D / 3D conversion mode image display device that can realize high luminance even in a 3D image.

According to an aspect of the present invention, there is provided a 2D / 3D switching mode image display device comprising: a display unit; A cholesteric liquid crystal panel configured under the display unit and serving as a switching means for mutually converting a two-dimensional image and a three-dimensional image displayed on the display unit; A phase difference film formed between the display unit and the cholesteric liquid crystal panel; It includes a light source configured in the lower portion of the cholesteric liquid crystal panel.

The display unit includes a liquid crystal panel and a first polarizing plate and a second polarizing plate disposed on the liquid crystal panel and having polarization axes perpendicular to each other.

The cholesteric liquid crystal panel includes: a first substrate defined by a plurality of first regions and a second region, and having a first electrode formed on a front surface thereof; A second substrate having a second electrode formed on a front surface thereof, and a portion corresponding to the first region having a second electrode pattern stacked thereon; And a cholesteric liquid crystal layer formed between the first substrate and the second substrate.

The cholesteric liquid crystal layer is characterized in that the vertical arrangement when a voltage is applied, the retardation film is characterized in that the film having a phase value of λ / 4.

When a voltage is applied to the first electrode and the second electrode, the cholesteric liquid crystal layer is vertically arranged, and the display unit displays a two-dimensional image.

When voltage is applied only to the first electrode and the third electrode pattern without applying a voltage to the second electrode, the cholesteric liquid crystal of the first region is in a vertically aligned state, and the collet of the second region is The steric liquid crystal layer is helically restored, and light is transmitted only to the first region to display a three-dimensional image.

A light source is further included below the cholesteric liquid crystal panel, and in the second region, left circularly polarized light passes through the cholesteric liquid crystal layer, passes through the retardation film, and is absorbed by the second polarizing plate, and right circularly polarized light is The light is reflected by the cholesteric liquid crystal layer and then reflected by the reflector of the light source to be irradiated to the first region.

The present invention is produced in the same manner as described above, with reference to the drawings will be described a preferred embodiment according to the present invention.

Example

The present invention is characterized in that a cholesteric liquid crystal panel is used as a switching means for switching between two-dimensional and three-dimensional images in manufacturing a 2D / 3D switching mode image display apparatus.

Before explaining the configuration of the 2D / 3D switching mode image display device according to the present invention, the polarization characteristics of the cholesteric liquid crystal will be described with reference to the drawings.

3 is a view for explaining the polarization characteristics of the cholesteric liquid crystal.

In general, the cholesteric liquid crystal 100 reflects only right circularly polarized light and does not reflect left circularly polarized light when the cholesteric liquid crystal molecular structure is twisted to the right.

When the liquid crystal molecules are twisted to the left, they have the opposite characteristics.

In the case of FIG. 3, it is assumed that it has a characteristic of reflecting right circularly polarized light and transmitting left circularly polarized light.

In order to use the cholesteric liquid crystal layer 100 as a part of the display device, a reflective means 102 for reflecting light is formed under the cholesteric liquid crystal layer 100, and the cholesteric liquid crystal layer ( At the top of 104, a retardation film (λ / 4) for converting circular light into linearly polarized light is configured.

In this case, it is assumed that a light source exists between the reflecting means 102 and the cholesteric liquid crystal layer 104.

In the above-described configuration, the light irradiated from the light source is a natural light source and unpolarized light in which left circular polarization and right circular polarization are mixed in half.

When the light reaches the cholesteric liquid crystal layer 100, the left circularly polarized light passes through the cholesteric liquid crystal layer 100 and becomes linearly polarized through the retardation film 104 to be emitted to the outside. do.

On the other hand, the right circularly polarized light is reflected by the cholesteric liquid crystal layer 100, which is reflected by the lower reflecting means 104 to become left circularly polarized light. Therefore, the reflected left circularly polarized light passes through the cholesteric liquid crystal layer 100 and is irradiated to the outside through the upper phase difference film 104.

As a result, since the left circular polarization and the right circular polarization can be used by using the selective reflection and transmission characteristics, the light efficiency is very high.

Therefore, when the above-described cholesteric liquid crystal panel is used as a parallax barrier layer, it is obvious that high brightness can be realized when displaying a 3D image.

Hereinafter, a 2D / 3D switching mode image display apparatus according to the present invention using the above-described cholesteric liquid crystal panel as 2D / 3D switching means will be described with reference to FIG.

4 is a cross-sectional view schematically showing the configuration of a 2D / 3D switch mode image display device according to the present invention.

As shown, the 2D / 3D switching mode image display device 199 according to the present invention is divided into a display unit D, a switching unit S, and a light source L. FIG.

The display unit S may use a liquid crystal panel having various modes. In the present invention, it is assumed that the display unit S is a TN liquid crystal panel 200 using a twisted nematic LC.

The TN liquid crystal panel 200 includes a first substrate 210 including color filters 212a, 212b, and 212c and a common electrode (not shown) corresponding to the pixel region P, and array wirings for each pixel region P. The second substrate 230 including the (not shown), the thin film transistor (not shown), and the pixel electrode 232, and the twisted nematic liquid crystal layer 240 filled between the first and second substrates 210 and 230. Include.

First and second polarizing plates 242a and 242b are formed on the upper and lower portions of the liquid crystal panel 200, respectively, such that the polarization axes are disposed perpendicular to each other.

A switching unit S is formed below the display unit D, and the switching unit S has a phase difference between the cholesteric liquid crystal panel 250 as a switching means and the upper portion of the cholesteric liquid crystal panel 250. The film 244 is constituted.

A light source L is positioned below the switching unit S, and is a backlight unit including a reflecting plate 260, a light guide plate 264, a lamp 262, and an optical sheet (not shown).

In the above-described configuration, the cholesteric liquid crystal panel 200, which is the switching means S, uses a cholesteric liquid crystal layer, and transmits left circularly polarized light and reflects right circularly polarized light. In addition, there is a characteristic that the vertical arrangement when a voltage is applied.

In the cholesteric liquid crystal panel 250 including the cholesteric liquid crystal layer 270, a plurality of first regions A1 and second regions A2 are alternately defined.

The first electrode 282 and the second electrode 284 are formed on the first substrate 280 and the second substrate 290 of the cholesteric liquid crystal panel 250, and the first region ( Only the portion corresponding to A1) is formed with a third electrode pattern 288 stacked between the two electrodes 284 and the insulating film 286.

Hereinafter, the principle of displaying the two-dimensional image will be described with reference to FIGS. 5A and 5B through the above-described configuration.

5A and 5B illustrate polarization characteristics of light in the first region and the second region of the cholesteric liquid crystal panel 250. (The description will be given with reference to FIG. 4).

As illustrated, when displaying a two-dimensional image, a voltage is applied to the first electrode 282 and the second electrode 284 of the cholesteric liquid crystal panel 250, so that the first region A1 and the second electrode are displayed. All of the cholesteric liquid crystal layers 270 positioned in the area A2 are driven.

In this way, the cholesteric liquid crystal layer 270 is vertically arranged in both the first and second regions A1 and A2, and the unpolarized light 300 irradiated from the light source below is cholesteric. The liquid crystal layer 270 passes through the upper retardation film 244 and reaches the second polarizing plate 242b of the upper display unit.

The light 300 that reaches the second polarizing plate 242b has only the linear polarization 232 of the component perpendicular to the polarization axis of the second polarizing plate 242b to reach the liquid crystal layer 240 of the liquid crystal panel 200. The liquid crystal layer 240 passes through the upper first polarizing plate 242a and exits to the outside.

That is, the cholesteric liquid crystal panel 250 displays a two-dimensional image because the cholesteric liquid crystal panel 250 does not have any optical effect in displaying the image on the display unit.

On the other hand, when displaying a 3D image, a voltage is applied only to the first and third electrodes 282 and 288 without applying a voltage to the second electrode 284, thereby maintaining the conventional vertical arrangement. The conventional second arrangement may display a three-dimensional image by restoring the original spiral cholesteric liquid crystal state without applying a voltage.

This will be described below with reference to FIG. 6.

6 is a schematic cross-sectional view of a configuration of an image display apparatus of a 2D / 3D switching mode according to the present invention for displaying a three-dimensional image.

As shown, when displaying a 3D image, a voltage is applied to the first electrode 282 and the third electrode pattern 288 in the first area A1, and no voltage is applied to the second electrode 284. Do not.

In this case, since the electric field is generated only in the first region A1, the cholesteric liquid crystal layer 272a of the first region A1 is forcedly vertically arranged by voltage, The two regions A2 are in the original spiral cholesteric liquid crystal 272b state.

Therefore, the light irradiated from the light source passes through the portion corresponding to the first region A1 as it is, and has a characteristic of being blocked at the portion corresponding to the second region A2, and thus the image of the parallax-barrier. It is possible to display a three-dimensional image by the split effect.

Hereinafter, the polarization characteristics of light in the first region and the second region of the cholesteric liquid crystal panel will be described with reference to FIGS. 7A and 7B.

7A and 7B are diagrams for explaining polarization characteristics of light in a first region and a second region of the cholesteric liquid crystal panel when displaying a 3D image. (The description will be given with reference to FIG. 6.)

As shown in FIG. 7A, when displaying a 3D image, a first region A1 is a region through which light is transmitted, and a voltage is applied to the first electrode 282 and the third electrode pattern 288 to prevent collet. The steric liquid crystal layers 272a are in a vertical arrangement.

Therefore, the unpolarized light 300 passing through the light source passes through the cholesteric liquid crystal layer 272a arranged vertically.

Next, the light is irradiated toward the second polarizing plate 242b on the upper side through the retardation film 233. At this time, only the linearly polarized light 304 parallel to the polarization axis of the second polarizing plate 242b among the light 300 passing through the retardation film reaches the upper liquid crystal panel.

Next, when the light 302 passing through the second polarizing film 242b undergoes a phase change while passing through the liquid crystal layer 240, the linearly polarized light 304 of the component parallel to the first polarizing film 242a is provided. This is emitted to the outside through the first polarizing film 242a.

On the other hand, as shown in FIG. 7B, the second region A2 is a region where light is blocked, and a voltage is applied only to the first electrode 282 and no voltage is applied to the second electrode 284. Since the cholesteric liquid crystal layer 272b is not affected by the electric field, the cholesteric liquid crystal layer 272b is present in the form of the spiral cholesteric liquid crystal 272b.

Therefore, right circularly polarized light (not shown) of the light 300 emitted from the light source is reflected by the cholesteric liquid crystal layer 272b, and the left circularly polarized light is transmitted through the cholesteric liquid crystal layer 272b.

At this time, the left circularly polarized light 310 passing through the cholesteric liquid crystal layer 272b passes through the upper phase difference film 244, and linearly polarized light 310 having a component perpendicular to the polarization axis of the second polarizing plate 242b. )

Therefore, even if the left circularly polarized light 310 passes through the cholesteric liquid crystal layer 272b, it is blocked by the second polarizing plate 242b through the phase change by the upper phase difference film 244, and as a result, the Light cannot be transmitted to the portion corresponding to the second area A2.

Therefore, the second region serves as a barrier to block light, and the first region serves as a slit through which light is transmitted, thereby operating as a 3D image by a parallax barrier image splitting effect.

However, the characteristic is that the right circularly polarized light (not shown) reflected by the cholesteric liquid crystal layer 272b is reflected by the reflector of the lower light source and irradiated upwardly through the first active region A1.

Therefore, unlike the prior art, since the light is not completely lost in the region where the light is not transmitted, but is reflected and transmitted to the first region, the brightness of the moon is improved as compared with the conventional art.

In addition, the configuration of the present invention is characterized in that the first and second polarizing plates 242a and 242b are used in the display unit unlike the related art.

In general, the polarizing plate, unlike the retardation film, has a filtering function to selectively transmit only specific light, which is one of the great causes of lowering the luminance.

Therefore, in this respect, the 2D / 3D conversion mode of the present invention has an advantage of realizing even higher brightness than the conventional.

As described above, since the cholesteric liquid crystal panel is used as the switching means for switching the image, the number of polarizing plates can be reduced and the optical efficiency can be maximized, so that a high brightness 2D / 3D switching mode image display device can be manufactured. It has an effect.

Claims (9)

A display unit; A cholesteric liquid crystal panel configured under the display unit and serving as a switching means for mutually converting a two-dimensional image and a three-dimensional image displayed on the display unit; A phase difference film formed between the display unit and the cholesteric liquid crystal panel; A light source configured under the cholesteric liquid crystal panel 2D / 3D conversion mode image display device comprising a. The method of claim 1, And the display unit includes a liquid crystal panel, and a first polarizing plate and a second polarizing plate disposed on the liquid crystal panel and having polarization axes perpendicular to each other. The method of claim 1, The cholesteric liquid crystal panel, Defined by a plurality of first regions and a second region, A first substrate having a first electrode formed on the front surface thereof; A second substrate having a second electrode formed on a front surface thereof, and a portion corresponding to the first region having a second electrode pattern stacked thereon; A cholesteric liquid crystal layer formed between the first substrate and the second substrate 2D / 3D conversion mode image display device comprising a. The method of claim 1, And the cholesteric liquid crystal layer is vertically arranged when voltage is applied. The method of claim 1, And the retardation film is a film having a phase value of [lambda] / 4. The method of claim 3, wherein When the voltage is applied to the first electrode and the second electrode, the cholesteric liquid crystal layer is vertically arranged, and the display unit displays a two-dimensional image, 2D / 3D conversion mode image display device. The method according to any one of claims 1 and 6, When voltage is applied only to the first electrode and the third electrode pattern without applying a voltage to the second electrode, the cholesteric liquid crystal of the first region is in a vertically aligned state, and the collet of the second region is The steric liquid crystal layer is helically restored, and the light is transmitted only to the first region to display a 3D image. The method of claim 7, wherein And a light source under the cholesteric liquid crystal panel. The method according to any one of claims 1 to 8, In the second region, the left circularly polarized light passes through the cholesteric liquid crystal layer, passes through the retardation film, and is absorbed by the second polarizing plate, and the right circularly polarized light is reflected by the cholesteric liquid crystal layer and again reflected by the reflector of the light source. 2D / 3D conversion mode image display device, characterized in that reflected and irradiated to the first area.

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