KR20130064333A - 2-dimensional and 3-dimensional display device without glasses - Google Patents

Abstract

According to an embodiment of the present invention, a display panel for displaying an image with light linearly polarized in a first direction, a polarizer for selectively converting light in the first direction into linearly polarized light in a second direction orthogonal thereto, and long and short axes An autostereoscopic 2D / 3D image display device including a liquid crystal lens that refracts or transmits linearly polarized light supplied from the polarizer using a liquid crystal cell having refractive anisotropy according to a direction to realize 2D and 3D images. .

Description

Glasses-free 2D / 3D image display device {2-Dimensional and 3-Dimensional Display Device without glasses}

The present invention relates to a stereoscopic image display device for displaying a two-dimensional image and a three-dimensional image in an autostereoscopic manner.

The stereoscopic image display device implements a 3D image using a stereoscopic technique or an autostereoscopic technique. The binocular parallax method uses parallax images of right and left eyes with large stereoscopic effect, and can be divided into a spectacular method and a non-spectacular method. The spectacle method displays the polarization direction of the left and right parallax image in a direct view display device or a projector by changing the polarization direction or time division method, and implements a stereoscopic image using polarized glasses or liquid crystal shutter glasses. In the autostereoscopic method, an optical component such as a parallax barrier and a lenticular lens for separating an optical axis of a left and right parallax image is generally installed in front of or behind a display screen to implement a stereoscopic image.

As an example of the autostereoscopic method, a method using a lenticular lens implements a 3D stereoscopic image by separating a right eye image and a left eye image with a lenticular lens. Since the method of using the lenticular lens cannot turn on / off the optical separation of the lenticular lens, only a 3D stereoscopic image can be realized and there is a disadvantage in that switching between the 3D stereoscopic image and the 2D planar image is impossible. In order to solve the shortcomings of the lenticular lens, a lenticular lens capable of switching 3D / 2D images by implementing a lenticular lens by electrically controlling the refractive index of the liquid crystal has been proposed (hereinafter, referred to as a "liquid crystal lenticular lens").

1 and 2, the liquid crystal lenticular lens 30 is disposed to be spaced apart from the display device 31 on which an image is displayed at a predetermined distance. As shown in FIG. 1, the liquid crystal lenticular lens 30 refracts the light incident from the display device 31 in the 3D image mode in which the liquid crystal molecules 34 are horizontally oriented so that the light path and the left eye image correspond to the right eye image. Separate the corresponding light path. In the 2D image mode in which an electric field is applied to the liquid crystal molecules of the liquid crystal lenticular lens 30, the liquid crystal molecules 34 are driven as shown in FIG. 2 to raise the liquid crystal molecules 34. As a result, the difference in refractive index between the liquid crystal molecules 34 and the transparent resin 35 is almost eliminated so that the light irradiated from the display device 31 passes through the liquid crystal lenticular lens 30 as it is.

The liquid crystal lenticular lens 30 should adjust the arrangement direction of the liquid crystal molecules 34 according to the 2D image and the 3D image. Therefore, an alignment layer should be formed on the intaglio pattern 35a and the transparent electrode 32. By the way, the lower alignment layer 33 is formed on a flat surface, so there is no problem in formation, but it is difficult to form the alignment layer in a uniform thickness on the upper plate due to the curved shape of the concave intaglio pattern 35a. Even if the alignment film is formed, it is difficult for the contact rubbing to the alignment film to be uniform. Therefore, since the alignment layer is formed only on the lower plate 40 in the liquid crystal lenticular lens, the switching speed of the liquid crystal molecules is slow and the liquid crystal molecules are not uniformly switched.

SUMMARY OF THE INVENTION An object of the present invention is to provide a new type of autostereoscopic 2D / 3D image display device, which is designed to overcome the above problems, so that the liquid crystal of a lenticular lens does not need to adjust its alignment direction.

According to an embodiment of the present invention, a display panel for displaying an image with light linearly polarized in a first direction, a polarizer for selectively converting light in the first direction into linearly polarized light in a second direction orthogonal thereto, and long and short axes An autostereoscopic 2D / 3D image display device including a liquid crystal lens that refracts or transmits linearly polarized light supplied from the polarizer using a liquid crystal cell having refractive anisotropy according to a direction to realize 2D and 3D images. Initiate.

The display panel may be configured as a liquid crystal panel operating in the TN mode.

The polarizer may be configured as a liquid crystal panel that polarizes the linearly polarized light in the second direction to linearly polarized light in the first direction or transmits the light as it is according to the dielectric anisotropy of the liquid crystal operating in the TN mode.

The polarizer may include a Faraday rotor that linearly polarizes the light polarized in the first direction or transmits the light linearly polarized in the second direction according to the Faraday effect.

The Faraday rotator is a magnetic thin film made of a magnetic material exhibiting a Faraday effect, and the first electric wiring and the second development wiring which are arranged in parallel with the magnetic thin film on both sides of the magnetic thin film and supply current in opposite directions to each other. It can be configured to include.

The liquid crystal lens has a first lens layer in which the long axis direction of the photocurable liquid crystal is aligned in the same direction as the second direction and cured; It may be configured to include a second lens layer having a refractive index.

In one embodiment of the present invention, it is not necessary to adjust the alignment direction of the liquid crystal molecules constituting the conventional liquid crystal lenticular lens according to the image, and to implement 2D image and 3D image according to the polarization axis of the linearly polarized light. Therefore, the problems caused by the alignment film must be formed on the curved surface as before, and also the problems such as the reaction rate or uniform switching of the liquid crystal molecules.

1 and 2 illustrate a liquid crystal lenticular lens according to the prior art.
3 is a view showing a schematic configuration of an autostereoscopic 2D / 3D image display device according to an embodiment of the present invention.
4 and 5 illustrate polarizers composed of liquid crystal molecules in FIG. 3.
6 and 7 illustrate polarizers composed of a Faraday rotator in FIG. 3.
FIG. 8 is a view for explaining a liquid crystal lens of FIG. 3.
9 and 10 are views illustrating a process of displaying a 2D image and a 3D image through an autostereoscopic 2D / 3D image display device according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, when it is determined that a detailed description of known functions or configurations related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

3 shows a schematic configuration of an autostereoscopic 2D / 3D image display device according to an embodiment of the present invention.

In FIG. 3, the image display device of this embodiment includes a display panel 100, a polarizer 200, and a liquid crystal lens 300, and has a structure in which they are sequentially stacked on a light propagation path.

The display panel 100 is a display device for displaying 2D image and 3D image data, and includes a liquid crystal display (LCD), a field emission display (FED), a plasma display panel, PDP), and flat panel display devices such as electroluminescence devices (EL) and electrophoretic display devices (EPD), including inorganic electroluminescent devices and organic light emitting diodes (OLEDs). Can be. Hereinafter, the display panel 100 will be described based on the display panel of the liquid crystal display device.

The display panel 100 has a structure in which a TFT substrate on which a pixel array is formed and a color filter substrate implementing color are sandwiched with a liquid crystal layer interposed therebetween. In the display panel 100, a polarizing plate having a light absorption axis of 90 ° is attached to the surfaces of the TFT substrate and the color filter substrate. Accordingly, the light incident on the display panel 100 in either the horizontal direction or the vertical direction is linearly polarized in a direction forming 90 ° with the light absorbing side of the incident light and exits the display panel 100.

The polarizer 200 is disposed in front of the display panel 100 and transmits the light supplied from the display panel 100 as it is or linearly polarizes the light by 90 ° to supply the liquid crystal lens 300 disposed above. For example, a liquid crystal panel having a liquid crystal layer operating in the TN mode may be preferably used as the polarizer 200, and a liquid crystal panel driving such as a VA mode, an IPS mode, or an FFS mode may also be used.

In addition, the polarizer 200 may be a panel composed of a Faraday rotator. Faraday rotator refers to a material for polarizing the incident light according to the Faraday effect, which will be described later in detail.

The liquid crystal lens 300 is disposed in front of the polarizer 200 and according to the polarization direction of the light incident from the polarizer 200, displays the 2D image by transmitting the light as it is, or corresponds to the light and the left eye image corresponding to the right eye image. 3D image is displayed by separating the light path.

Hereinafter, configurations of the polarizer 200 and the liquid crystal lens 300 will be described in detail with reference to the accompanying drawings. 4 is a cross-sectional view illustrating a structure of a polarizer 200 formed of a liquid crystal panel operating in a TN mode.

In FIG. 4, the polarizer 200 has a structure in which the liquid crystal layer 250 is sandwiched between the lower substrate 210 and the upper substrate 220.

Each of the lower substrate 210 and the upper substrate 220 is made of glass or transparent plastic. The lower electrode 210 and the upper electrode 220 are formed on the entire surfaces of the substrates 210 and 220 on the surfaces of the lower substrate 210 and the upper substrate 220, and transparent conductive materials such as ITO and IZO are used. It is made of matter.

The liquid crystal layer 250 is disposed between the two electrodes 210 and 220. The liquid crystal molecules constituting the liquid crystal layer 250 are made of positive liquid crystals. A positive liquid crystal is a liquid crystal defined by Δε> 0 in which the long-term dielectric constant? Of the liquid crystal molecules is larger than the short-term dielectric constant ε┴. These liquid crystals are disposed between the upper and lower alignment layers, which are not shown, and are pre-tilted. In the TN mode, these liquid crystals are arranged to rotate the vertical linear flat light of the incident light in the absence of an electric field by 90 ° to change the horizontal linear polarized light (FIG. 5A). When applied, it is arranged to transmit light as it is (FIG. 5B). Accordingly, as illustrated in FIG. 5A, in a state where no electric field is applied, the polarizer 200 transmits light having a polarization axis in a vertical direction by linearly polarizing light having a polarization axis in a horizontal direction ↔. . In addition, as illustrated in FIG. 5B, in a state where an electric field is applied, the polarizer 200 transmits light having a vertical polarization axis as it is, and thus the polarization axis of transmitted light also forms a vertical direction.

6 is a cross-sectional view showing the structure of a polarizer 200a made of a Faraday rotator.

In FIG. 6, the polarizer 200a has a structure in which Faraday rotors FS1 to FS3 are sandwiched between the lower substrate 210a and the upper substrate 220a.

Each of the lower substrate 210 and the upper substrate 220 is made of glass or transparent plastic. On the surface of the lower substrate 210, the first to third electrodes including the first thin film ML and the second thin film ML are disposed between the first thin film ML and the second thin film ML. Faraday Rotors are deployed. In the present exemplary embodiment, the polarizer 200a is configured in such a manner that three Faraday rotors are arranged, but the polarizer 200a may be adjusted to an appropriate number according to the size of the display panel 100.

The magnetic thin film ML is formed by dispersing a magnetic material (eg, garnet) having a Faraday effect in a transparent resin, and has a thin film thickness to allow light to pass therethrough. The magnetic thin film has a predetermined width on the lower substrate 210a and forms a strip. On both sides of the magnetic thin film ML, the first electrical wiring EBL1 and the second electrical wiring EBL2 are arranged in parallel with the magnetic thin film ML. The electrical wirings EBL1 and EBL2 are formed of a thin film made of copper or aluminum (Al) having excellent conductivity.

The Faraday rotors FS1 to FS3 configured as described above are covered with a dielectric layer 270a made of a dielectric material.

On the other hand, the Faraday effect is that when light linearly polarized in the same direction as the magnetic field on the object is incident, the light passing through the material is rotated in proportion to the distance passed, and the angle is proportional to the magnitude of the magnetic field at a given distance. When expressed as a formula, it satisfies the relationship of θ = VB, θ = rotated angle, V = distance passed, and B = magnetic field strength.

FIG. 7 illustrates the principle that light linearly polarized by the Faraday effect is polarized while transmitting the Faraday rotor having the above-described structure. In this figure, light linearly polarized in the vertical direction is described as passing through a Faraday rotor.

In FIG. 7, when a current flows in the + z axis direction ⊙ in the first electric wiring EBL1, a first induced magnetic field B1 is formed around the first electric wiring EBL1. The direction of the first induced magnetic field B1 is formed in the counterclockwise direction as shown in FIG. 7 by the Fleming right hand rule. At the same time, when the -z direction current flowing in the opposite direction flows through the second electric wiring EBL2, a second induction magnetic field B2 is formed around the second electric wiring EBL2. The direction of the second induced magnetic field B2 is formed clockwise as shown in FIG. 7 according to the Fleming right hand rule.

That is, when the current is supplied to the first electrical wiring EBL1 and the second electrical wiring EBL2, respectively, as shown in FIG. 7, the magnetic thin film ML is applied to the current flowing in the anti-parallel directions from both sides. As a result, a vertical magnetic field BP flowing in the + y axis direction is formed. Accordingly, the direction of the vertical magnetic field BP and the direction of linearly polarized light become the same, so that the polarization axis rotates while transmitting the Faraday rotor according to the Faraday effect, so that the vertical linear polarization is the horizontal (↔) linear polarization. Will change to

Hereinafter, the liquid crystal lens will be described with reference to FIG. 8. In FIG. 8, the liquid crystal lens 300 has a structure in which a liquid crystal cell (LCC) formed of a first lens layer 330 and a second lens layer 340 is sandwiched between two substrates 310 and 32.

Each of the lower substrate 310 and the upper substrate 320 is made of glass or transparent plastic.

The first lens layer 330 having the convex lens surface 330a is formed on the lower substrate 310. The first lens layer 330 is formed by curing the photocurable liquid crystal in a state of being aligned in the horizontal direction. Therefore, the liquid crystals constituting the first lens layer 330 permanently maintain the horizontally oriented form at all positions regardless of the layer. When the photocurable reactive monomor or reactive mesogen is irradiated with polarized UV, the double photocurable liquid crystal is cured while maintaining its initial orientation in accordance with the polarized light of UV. The first lens layer 330 is formed.

The refractive index anisotropy of the liquid crystal of the first lens layer 330 configured as described above shows the first refractive index ne and the second refractive index no along the direction. The liquid crystal exhibits a first refractive index ne in the major axis direction but a second refractive index no smaller than the first refractive index ne in the minor axis direction. Therefore, since the liquid crystal constituting the first lens layer 330 is arranged in the horizontal direction (the x-axis direction in the drawing), that is, the long-axis direction of the liquid crystal and the x-axis direction in the drawing are arranged in the same direction, the first lens layer 330 Denotes the first refractive index ne in the horizontal direction (x-axis direction in the drawing). In comparison, the z-axis direction in the drawing is the same as the direction in which the short axis of the liquid crystal is arranged, and thus the second refractive index no is shown in this direction (z-axis direction in the drawing).

The second lens layer 340 covering the convex lens surface 330a is formed on the first lens layer 330 configured as described above. The second lens layer 340 may be formed of a transparent resin, and has a second refractive index no equal to the uniaxial refractive index of the liquid crystal.

Hereinafter, a process of displaying a 2D image and a 3D image in the 2D / 3D image display device configured as described above will be described with reference to FIGS. 9 and 10. In FIG. 9, three pixels px1 to px3 correspond to one lens, and the polarizer 200 is configured by sandwiching the Faraday rotor FS.

In the 3D image mode in which a magnetic field is formed, the display panel 100 supplies light having a vertical polarization axis to the polarizer 200. In the state where the magnetic field is formed, that is, when the reverse current is supplied to the first electric wiring EBL1 and the second electric wiring EBL2 of the Faraday rotor, the Faraday rotor forms a magnetic field in the same direction as the traveling direction of light. Accordingly, due to the Faraday effect, light incident on the polarizer 200 having a vertical polarization axis passes through the polarizer 200 by changing the polarization axis from the vertical direction to the horizontal direction ↔.

As a result, the linearly polarized light having the polarization axis in the horizontal direction ↔ is supplied to the liquid crystal lens 300. On the other hand, the liquid crystal cell (LCC) of the liquid crystal lens 300 is in a state that the liquid crystal is aligned in the horizontal direction, as shown in Figure 10, the long axis of the liquid crystal and the polarization axis of light are the same in the horizontal direction (↔) . As described above, since the polarization axis of light and the long axis direction of the liquid crystal are the same, the first lens layer 330 exhibits a first refractive index ne.

In comparison, the second lens layer 340 disposed on the convex lens surface 330a has a second refractive index no, so that the light in the block lens surface 330a is refracted according to Snell's law. The light travel path corresponding to the right eye image and the light travel path corresponding to the left eye image are divided into different focal points, and 3D images are displayed.

In the 2D image mode in which no magnetic field is formed, the display panel 100 supplies light having a vertical polarization axis to the polarizer 200. In a state in which no magnetic field is formed, that is, when no current is supplied to the first electric wiring EBL1 and the second electric wiring EBL2, the Faraday rotor transmits the supplied light as it is. Therefore, light having a vertical polarization axis and incident to the polarizer 200 passes through the polarizer 200 as it is and is supplied to the liquid crystal lens 300 as light having a vertical polarization axis.

On the other hand, the liquid crystal cell (LCC) of the liquid crystal lens 300 has a state in which the liquid crystal is aligned in the horizontal direction, as shown in FIG. 10, the short axis of the liquid crystal and the polarization axis of light are the same in the vertical direction. . As described above, since the polarization axis of the light and the uniaxial direction of the liquid crystal are the same, the first lens layer 330 exhibits a second refractive index no.

In comparison, the second lens layer 340 disposed thereon at the boundary of the convex lens surface 330a has a second refractive index no, such that the first lens layer 330 and the second lens layer 340 are formed. There is no difference in refractive index between. Therefore, the light is transmitted through the block lens surface 330a as it is and a 2D image is displayed.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

Claims (6)

A display panel displaying an image with light linearly polarized in a first direction;
A polarizer for selectively converting the light in the first direction into linearly polarized light in a second direction orthogonal thereto;
A liquid crystal lens for realizing 2D and 3D images by refracting or transmitting the linearly polarized light supplied from the polarizer using a liquid crystal cell having refractive index anisotropy according to a long axis and a short axis.
Glasses-free 2D / 3D image display device comprising a. The method of claim 1,
The display panel is an auto glasses type 2D / 3D image display device which is a liquid crystal panel operating in the TN mode. The method of claim 2,
The polarizer is an autostereoscopic 2D / 3D liquid crystal panel in which the linearly polarized light in the second direction is polarized by the linearly polarized light in the first direction or transmitted as it is according to the dielectric anisotropy of the liquid crystal operating in the TN mode. Video display device. The method of claim 2,
And the polarizer comprises a Faraday rotor which linearly polarizes the light polarized in the first direction or transmits the light polarized in the first direction according to the Faraday effect. The method of claim 4, wherein the Faraday rotor,
A magnetic thin film made of a magnetic material having a Faraday effect,
An autostereoscopic 2D / 3D image display device disposed on both sides of the magnetic thin film and parallel to the magnetic thin film and including a first electric wiring and a second developing wiring for supplying currents in opposite directions. The method of claim 1,
The liquid crystal lens includes a first lens layer in which the major axis direction of the photocurable liquid crystal is aligned in the same direction as the second direction and cured;
And a second lens layer having a refractive index equal to a uniaxial refractive index of the liquid crystal on the first lens layer with a convex lens surface as an interface.

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