KR100218510B1 - Lcd device using iodine - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to a display device for displaying an image by passing light through a panel consisting of upper and lower substrates.

Between the upper substrate and the lower substrate, a liquid crystal material or a nonpolar solvent and a polarizing material having strong anisotropy are mixed and injected. Therefore, the display device according to the present invention uses only one polarizing plate, by mixing a liquid crystal material or a non-polar solvent and a polarizing material injected between the two substrates to use a polarizing material as a polarizer, thereby minimizing the cost and thickness of the module, It is possible to implement a display device that improves reliability, does not belong to the conditions of Δε or Δn to select a liquid crystal material, increases the transmittance of the display device, and improves process yield by simplifying the manufacturing process. .

Description

Display device using iodine

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a display device, and more particularly, to a display device for displaying an image by passing light through a panel consisting of upper and lower substrates.

In general, a polarizing plate is a device used to obtain polarized light having an electric or magnetic field that vibrates in only one direction through light, or to investigate whether incident light is polarized light.

Looking at the structure of the general polarizing plate and the manufacturing process of the polarizer in more detail as follows.

1 is a cross-sectional view illustrating a structure of a polarizing plate according to a general technique, and FIG. 2 is a view illustrating a manufacturing process of a general polarizer.

As shown in FIG. 1, there is a support 20 for supporting the polarizer 10 at the upper and lower sides of the polarizer 10, and a protective film 30 is attached to the upper portion of the upper support 20. An adhesive 40 is applied to the lower portion of the lower supporter 20 to attach to the liquid crystal display.

In the method of manufacturing the polarizer 10 used in such a polarizing plate, as shown in FIG. 2A, first, an aqueous solution of potassium iodide (KI) having high anisotropy is made of a film 911 formed of a polymer, polyvinyl alcohol (PVA). Soak in the iodine molecules (I2) to adsorb the polyvinyl alcohol (PVA) molecules.

Here, the iodine molecule (I2) has a rod shape having a long axis and a short axis, and is adsorbed in an arbitrary direction.

Next, in a state in which iodine (I 2) and polyvinyl alcohol (PVA) molecules are arranged in an arbitrary direction, the film 11 of polyvinyl alcohol is stretched in the horizontal direction to give uniform anisotropy in one direction. Then, the polymer of polyvinyl alcohol (PVA) is stretched in the stretching direction, and in this case, the anisotropic strong iodine molecule (I2) is fixed in the major axis direction according to the stretching direction of the polymer.

The polarization phenomenon of the polarizer 10 is caused by iodine (I2) having high anisotropy, and when light passes through the polarizer 10, the polarized light vibrating vertically in the elongated direction, that is, in the long axis direction of the iodine molecule, passes as it is. The light oscillating in the direction of the long axis of the iodine molecule is absorbed by thermal energy or the like by interfering with the electron cloud of the iodine molecule I 2.

Such polarizing plates are frequently used in liquid crystal display devices and the like which require a change in the amount of light transmission.

Currently, the most active liquid crystal display devices are one substrate having a pixel electrode, another substrate having a common electrode, and a liquid crystal material interposed therebetween. consist of. In the liquid crystal display, in order to drive the liquid crystal molecules, it is common to apply a voltage to the pixel electrode and the common electrode to form an electric field in a direction perpendicular to the two substrates. In this case, a twisted-nematic (TN) method is mainly used in which liquid crystal molecules are twisted 90 ° from one substrate to another. The light incident perpendicularly to the substrate is rotated by 90 ° along the distortion of the liquid crystal molecules when passing through the liquid crystal cell consisting of the two substrates. In order to use this change as a change in light transmittance, polarizers are attached to the upper and lower parts of the cell, respectively. When the polarization directions of the two polarizers are installed perpendicular to each other, the linearly polarized light passing through one polarizer is rotated by 90 ° and thus passes through the other polarizer as it is, thus becoming bright. Therefore, it is called a normally white mode. . When a voltage is applied to the common electrode and the pixel electrode of the liquid crystal cell, the liquid crystal molecules are rearranged in the electric field direction by the dielectric anisotropy so that the optical fluorescence of the light disappears, and the incident polarized light does not pass through the other polarizer after passing through the liquid crystal cell. It becomes the dark state. When the polarization directions of the two polarizers are installed in parallel, the polarization directions of the two polarizers are opposite to the previous cases and become dark in the state where no voltage is applied.

In addition, the planar driving type liquid crystal display is a method of driving a liquid crystal display by forming both a pixel electrode and a common electrode on one substrate, unlike a general method using a potential value between two substrates. It is a method of causing the liquid crystal molecules to react by giving a position.

In such a planar driving type liquid crystal display, the arrangement direction of the liquid crystal molecules is changed by using potential values of the common electrode and the pixel electrode, and the polarized light that has passed one polarizer is rotated along the arrangement direction of the liquid crystal molecules. In the state where the light passes through the other polarizer and no voltage is applied, the liquid crystal molecules do not induce the polarization direction of the polarized light to pass through the other polarizer, resulting in a dark state.

In order to change the light transmittance in the TN type liquid crystal display device or the planar drive type liquid crystal display device, it is essential to attach a polarizing plate to the upper substrate and the lower substrate.

However, in such a conventional liquid crystal display device, since the polarizers must be attached to the upper and lower substrates, the cost is increased, the thickness of the module is increased, and in the case of the iodine polarizer, the reliability is lowered due to the sublimation, and the transmittance is reduced. I have a problem.

In addition, in order to propagate the liquid crystal material by using the properties of the birefringence and the photorefractive property of the liquid crystal material, the difference between the dielectric constant and refractive index in the major axis direction and the dielectric constant and refractive index in the minor axis direction (Δε, Δn) must be considered. Thickness adjustment is required.

SUMMARY OF THE INVENTION The present invention has been made to solve such a problem, to minimize the cost and thickness of the module, to improve reliability, and to provide a display device independent of Δε or Δn for selecting a liquid crystal material.

1 is a cross-sectional view showing the structure of a polarizing plate according to a general technique,

2 is a view showing a manufacturing process of a general polarizing plate,

3 to 7 illustrate driving principles of a display device according to an exemplary embodiment of the present invention.

In the display device according to the present invention, a liquid crystal material or a nonpolar solvent and a strong anisotropic polarization material are mixed and injected between the upper substrate and the lower substrate.

The polarizing plate is attached to one of the upper and lower substrates.

In the liquid crystal display device in which the liquid crystal material is injected among the display devices, the polarization phenomenon depends on the polarizing material, and the polarizing material is dispersed inside the panel composed of two substrates to serve as a polarizer. The liquid crystal material is arranged in accordance with the direction of the electric field generated by the voltage applied to the pixel electrode and the common electrode.

In such a liquid crystal display, a voltage may be applied in a vertical direction of two substrates, or a voltage may be applied in parallel directions of two substrates as in a planar driving method.

In addition, a voltage may be applied by aligning the liquid crystal material perpendicular to the two substrates using the alignment layer.

The liquid crystal material may have a positive anisotropy arranged in parallel with the electric field direction and a negative anisotropy arranged perpendicular to the direction of the electric field.

In the display device in which the non-polar solvent is injected, the light transmittance is determined by determining the arrangement direction of the polarized material injected by applying a voltage.

Here, the polarizing material uses iodine molecule (I ₂ ) having strong anisotropy.

In the liquid crystal display using iodine according to the present invention, the iodine molecules are arranged in parallel with the liquid crystal molecules as polymers so that the long axis direction of the liquid crystal molecules and the long axis direction of the iodine molecules are arranged in parallel. Therefore, the arrangement direction of the liquid crystal molecules can be changed by applying an electric field, and the arrangement direction of the iodine molecules can be changed at the same time. Thus, the polarization direction of the transmitted light can be changed according to the arrangement direction of the iodine molecule.

In addition, in the liquid crystal display device using the iodine according to the present invention by mixing the liquid crystal material or non-polar solvent and the polarizing material injected between the two substrates to use the polarizing material instead of the polarizing plate, the cost and the thickness of the product is reduced, iodine The amount of sublimation decreases and does not belong to the conditions of Δε or Δn for selecting the liquid crystal material.

Next, embodiments of the display device according to the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention.

3 to 7 illustrate driving principles of a display device according to an exemplary embodiment of the present invention.

3 is a cross-sectional view applied to a flat panel liquid crystal display, in which FIG. 3A is not in a voltage state, and FIG. 3B is in a state in which a voltage is applied.

As shown in FIG. 3A, the liquid crystal material 300 and the iodine 400, which is a polarizing material having strong anisotropy, are injected between the two substrates 100 and 200. The polarizing plate 500 is attached to one of the two substrates 100 and 200, and the arrow direction is the polarization direction. In this case, the liquid crystal molecules of the liquid crystal material 300 are arranged in parallel with the two substrates 100 and 200 according to the alignment direction of an alignment layer (not shown) formed on the substrates 100 and 200. In addition, since the iodine molecules of the iodine 400 are arranged in the direction in which the polymers are arranged, the iodine molecules are arranged in parallel with the alignment direction of the liquid crystal molecules.

In the state where the electric field is not applied, light incident on the polarizer 500 is polarized in the direction of the polarization axis of the polarizer. Subsequently, since the polarized light is perpendicular to the arrangement direction of the liquid crystal material 300 and the iodine 400, that is, perpendicular to the long axis direction of the iodine molecule, the polarized light is transmitted through the iodine 400 so that the screen displays white ( Normally white mode).

Next, as shown in FIG. 3B, when a voltage is applied, an electric field is formed in parallel with the two substrates 100 and 200. In this case, the liquid crystal molecules of the liquid crystal material 300 are twisted in the horizontal direction in a state parallel to the two substrates 100 and 200 according to the direction of the electric field, and the iodine molecules of the iodine 400 are also parallel to the alignment direction of the polymer. As a result, the liquid crystal is returned along the alignment direction of the liquid crystal molecules.

In this case, since the long axis direction of the iodine molecule of the iodine 400 is parallel to the polarization side direction of the polarizer 500, the polarized light passing through the polarizer 500 is absorbed by the electron cloud of the iodine molecule to display black.

In the above-mentioned case, in the state in which no voltage is applied, the polarization direction of the polarizer 500 and the long axis direction of the iodine molecule of the iodine 400 are vertically arranged, but the polarization direction is different from the long axis direction of the iodine molecule. When the polarizer 500 is installed in parallel, the display in the normally black mode is possible.

Here, the polarizer may be attached to either the upper substrate 100 or the lower substrate 200, and other materials having high anisotropy may be used instead of the iodine 400.

4 is a cross-sectional view applied to the liquid crystal display of the flat driving method, in which FIG. 4A is a state in which no voltage is applied, and FIG. 4B is a state in which a voltage is applied.

In the state in which no voltage is applied, all light polarized in the same manner as in FIG. 3A is transmitted through the iodine 400 to display white color.

Next, as shown in Figure 4b, when a voltage is applied, the electric field is formed in the horizontal direction in parallel to the two substrates (100, 200). Here, since the liquid crystal material 300 is negative anisotropy, the liquid crystal molecules are not moved because they are arranged perpendicularly to the electric field direction, and since the iodine molecules of the iodine 400 have polarity in the long axis direction, they are rearranged according to the direction of the electric field. do. Therefore, the long axis direction of the iodine molecule of the iodine 400 and the polarization direction of the polarizer 500 are parallel to each other, and the polarized light is absorbed by the electron cloud of the iodine 400 to display black.

In the above-mentioned case, the polarization direction and the long axis direction of the liquid crystal molecules 300 and the iodine 400 are vertically arranged in the state where no voltage is applied, but the polarization direction is the liquid crystal molecules 300 and the iodine 400. When the polarizer is installed so as to be parallel to the major axis direction of), nomeryl black mode can be displayed.

Here, the polarizing plate is the same as the above-described embodiment, either the upper substrate 100 or the lower substrate 200 is attached to either, it is also possible to use another material having a high anisotropy instead of the iodine 400.

FIG. 5 is a cross-sectional view applied to a general liquid crystal display, where FIG. 5A is a state in which no voltage is applied, and FIG. 5B is a state in which a voltage is applied.

As shown in FIG. 5A, an iodine 400, which is one of the liquid crystal material 300 and the highly anisotropic polarizing material, is injected between the two substrates 100 and 200, and one substrate 100 of the two substrates 100 and 200 is injected. ) Is attached to the polarizing plate 500, the arrow direction is the polarization direction of the polarizing plate 500. Herein, the liquid crystal molecules 300 are arranged along the alignment direction of an alignment layer (not shown) formed on the two substrates 100 and 200, and are arranged perpendicular to the two substrates 100 and 200, and the molecules of the iodine 400 are aligned. In addition, they are arranged along the alignment direction of the liquid crystal molecules, which are polymers, and are perpendicular to the two substrates 100 and 200.

The light incident on the polarizer 500 passes through only the light in the polarization direction, thereby making polarized light. At this time, since the molecules of the iodine 400 are vertically aligned with respect to the two substrates 100 and 200, the polarized light is isotropic with respect to the vibration direction of the polarized light, and thus the polarized light is transmitted and displayed in white. (Normally white mode)

Next, as shown in FIG. 5B, when a voltage is applied, the electric field is formed in the vertical direction. At this time, the molecules of the liquid crystal material 300 are negatively anisotropic so that the liquid crystal material 300 is perpendicular to the direction of the electric field. The molecules of are arranged parallel to the two substrates 100 and 200, and the molecules of the iodine 400 are also rotated parallel to the two substrates 100 and 200 along the molecules of the liquid crystal material 300 and rearranged. In this case, the long axis directions of the liquid crystal molecules 300 and the iodine 400 are parallel to the two substrates 100 and 200, and parallel to the vibration directions of the polarized light passing therethrough, thereby displaying black.

Here, the difference from the TN driving type liquid crystal display device is that the liquid crystal molecules are twisted 90 ° from the lower substrate 200 to the upper substrate 100 without using the polarizing plate, whereas in the embodiment of the present invention, only one polarizing plate is used and the twisting is performed. It is not a structure, but is to mix a polarizing material with a liquid crystal material.

Here, the polarizer may be attached to either the upper substrate 100 or the lower substrate 200, and other materials having high anisotropy may be used instead of the iodine 400.

6 is a cross-sectional view applied to a display device, in which FIG. 6A is a state in which no voltage is applied and FIG. 6B is a state in which a voltage is applied.

Here, the iodine 400, which is a polarizing material, is uniformly arranged in the direction of the electric field, serves to induce a polarization phenomenon, and the solvent uses a nonpolar solvent, not a liquid crystal material.

As shown in 6a, the iodine 400, which is one of the nonpolar solvent 500 and the highly anisotropic polarizing material, is injected between the two substrates 100 and 200. The light incident in the state in which the electric field is not applied vibrates in all directions, and since the iodine 400 is also arranged in an arbitrary direction, all incident light is absorbed by the iodine and displayed in black.

Next, as shown in FIG. 6B, when a voltage is applied, the electric field is formed perpendicular to the two substrates 100 and 200, and the iodine 400 is also rearranged along the direction of the electric field. Therefore, the iodine 400 loses polarization function with respect to incident light and all incident light is transmitted to display white color.

The feature here is not to use liquid crystal, but to use a non-polar solvent, the use of a polarizing plate does not have a large effect, it is also possible to use another material having a large anisotropy instead of iodine (400).

FIG. 7 is a cross-sectional view applied to a general liquid crystal display, and FIG. 3A is a state where no voltage is applied, and FIG. 3B is a state where a voltage is applied.

As shown in FIG. 7A, iodine 400, which is one of the liquid crystal material 300 and the highly anisotropic polarizing material, is injected between the two substrates 100 and 200. In the state in which no voltage is applied, the major axis directions of the liquid crystal material 300 and the iodine 400 are arranged parallel to the two substrates 100 and 200 by the alignment process of the liquid crystal molecules. The polarizing plate 500 is attached to one of the two substrates 100 and 200, and the arrow direction is the polarization direction and is parallel to the long axis direction of the molecules of the liquid crystal material 300 and the iodine 400.

Therefore, the light incident on the polarizing plate is made of a polarized light having an electric or magnetic field oscillating in the polarization direction, and since the light is parallel to the long axis direction of the iodine 400, all the polarized light is absorbed by the electron cloud of the iodine 400 Black is displayed. (Normally black mode).

Next, as shown in Figure 7b, when a voltage is applied, the electric field is formed perpendicular to the two substrates (100, 200), wherein the liquid crystal material 300 is positive anisotropy, the liquid crystal molecules are perpendicular to the electric field direction The iodine 400 molecules are also vertically aligned and rearranged along the alignment direction of the liquid crystal molecules.

In this case, since the iodine 400 molecules are vertically arranged with respect to the polarized light, the iodine 400 molecules do not feel refractive index anisotropy, and all of the polarized light is transmitted to display white color.

Here, the polarizer 500 may be attached to either the upper substrate 100 or the lower substrate 200, and other materials having high anisotropy may be used instead of the iodine 400.

Here, the difference from the TN driving type liquid crystal display device is that the liquid crystal molecules are twisted 90 ° from the lower substrate 200 to the upper substrate 100 without using the polarizing plate, whereas in the embodiment of the present invention, only one polarizing plate 500 is used. It is not used in a twisted structure, but in mixing polarizing materials with liquid crystal materials.

Therefore, the display device according to the present invention uses only one polarizing plate, by mixing a liquid crystal material or a non-polar solvent and a polarizing material injected between the two substrates to use a polarizing material as a polarizer, thereby minimizing the cost and thickness of the module, It is possible to implement a display device that improves reliability, does not belong to a condition of Δε or Δn in selecting a liquid crystal material, increases transmittance of the display device, and improves process yield by simplifying a manufacturing process. .

Claims (25)

And an anisotropic polarizing material mixed with the liquid crystal material between the upper and lower substrates, and a liquid crystal material injected between the upper and lower substrates. The liquid crystal display of claim 1, further comprising a polarizer attached to one of the upper substrate and the lower substrate. The liquid crystal display of claim 2, further comprising an alignment layer formed on the upper substrate and the lower substrate. The liquid crystal display of claim 3, wherein the common electrode and the pixel electrode are formed on one of the upper substrate and the lower substrate. 5. The liquid crystal display of claim 4, wherein long axis directions of the liquid crystal material and the polarizer material are parallel to the two substrates. The liquid crystal display of claim 5, wherein, when voltage is applied, long axes of the liquid crystal material and the polarizer material rotate in a direction parallel to the two substrates. The liquid crystal display of claim 6, wherein the liquid crystal material is positive anisotropy. The liquid crystal display of claim 7, wherein the polarizing material is iodine. The liquid crystal display of claim 8, wherein when a voltage is applied, a long axis of the polarizing material rotates in a direction parallel to the two substrates, and a long axis of the liquid crystal material does not rotate. The liquid crystal display of claim 9, wherein the liquid crystal material is negative anisotropy. The liquid crystal display of claim 10, wherein the polarizing material is iodine. The liquid crystal display of claim 3, wherein a pain electrode is formed on one of the upper and lower substrates, and a pixel electrode is formed on the other substrate. The liquid crystal display of claim 12, wherein the long axes of the liquid crystal material and the polarizing material are arranged perpendicular to the two substrates by the alignment force of the alignment layer. The liquid crystal display of claim 13, wherein, when voltage is applied, long axes of the liquid crystal material and the polarizer material rotate in a direction parallel to the two substrates. The liquid crystal display of claim 14, wherein the liquid crystal material is negative anisotropy. The liquid crystal display of claim 15, wherein the polarizing material is iodine. The liquid crystal display of claim 12, wherein major axes of the liquid crystal material and the polarizing material are arranged in parallel with respect to the two substrates by the alignment force of the alignment layer. The liquid crystal display of claim 17, wherein, when voltage is applied, long axes of the liquid crystal material and the polarizer material rotate perpendicularly to the two substrates. The liquid crystal display of claim 18, wherein the liquid crystal material is positive anisotropy. The liquid crystal display of claim 19, wherein the polarizing material is iodine. A non-polar solvent injected between an upper substrate and a lower substrate, and an anisotropic polarizing material mixed with the non-polar solvent between the upper substrate and the lower substrate. The display device of claim 21, wherein a common electrode is formed on one of the upper and lower substrates, and a pixel electrode is formed on the other substrate. The display device of claim 22, wherein a long axis of the polarizing material is arranged in an arbitrary direction without a voltage applied thereto. The liquid crystal display of claim 23, wherein when a voltage is applied, a long axis of the polarizing material rotates perpendicularly to the two substrates. The liquid crystal display of claim 24, wherein the polarizing material is iodine.