KR100210376B1 - Molecular array apparatus and method for photo-functional lc orientation layer - Google Patents

Abstract

The present invention not only arranges molecules of the photofunctional polymer liquid crystal alignment layer by controlling the intensity of polarized light beams from the outside, but also applies heat and an electric field to the photoelectric polymer liquid crystal alignment layer before applying light and preferentially to an electric field. By arranging the molecules of the photofunctional polymer liquid crystal alignment layer by irradiating the polarized light and rearranging the molecules of the liquid crystal alignment layer by the polarized light rays can be produced a photofunctional polymer liquid crystal alignment layer excellent in uniformity of the arrangement of the molecules.

Description

Molecular Array and Molecular Array of Photofunctional Polymer Liquid Crystal Alignment Film

1 is a diagram illustrating a photoisomerization process of a transmode or cismode of a general photofunctional polymer.

2 (a) to 2 (c) is a view showing a photoisomerization process that is converted when the ultraviolet light polarized in the P direction parallel to the y-axis direction to the optical functional polymer used in the present invention.

3 (a) to 3 (c) is a view showing a photoisomerization process that is converted when the ultraviolet light polarized in the S direction parallel to the x-axis direction to the optical functional polymer used in the present invention.

4 is a device for arranging molecules of a photofunctional polymer liquid crystal aligning film for irradiating light polarized from an upper part of the electrode and a counter electrode for applying an electric field to the photofunctional polymer liquid crystal aligning film according to the present invention. Shown cross section.

5 (a) to 5 (c) is a graph showing a time-dependent change in temperature, the intensity of the electric field, the intensity of the polarized light beam according to the present invention.

6 (a) to 6 (d) are sections showing the arrangement change of molecules of the liquid crystal alignment film according to the sections of FIGS. 5 (a) to 5 (c).

7 is a view showing the direction between the electric field and the molecular dipole of the polymer when an electric field is applied to the photofunctional polymer liquid crystal alignment film according to the present invention.

* Explanation of symbols for main parts of the drawings

1: Trans mode 2: Sheath mode

3: polarized ultraviolet light 4: polarized visible light

5: Sheath mode in which the top of the chromophore is bent with z-axis

6: Sheath mode where the bottom of the chromophore is bent by the x-axis

7: Sheath mode in which the lower end of the chromophore is bent by the z axis

8: Sheath mode in which the bottom of the chromophore is bent with y-axis

9 glass substrate 10 transparent electrode

11: photofunctional polymer liquid crystal alignment film

12: molecule of photofunctional polymer liquid crystal alignment layer

13 heater 14 power supply

15: electric field 16: counter electrode

x y, z: Laboratory coordinate system V: External voltage

Is the polar angle between the electric field and the dipole of the strongly functional molecule

φ: azimuth Ep: electric field

Tg: vitrification temperature Ir: intensity of incident light

The present invention relates to a molecular arranging device and an arrangement method of the optically functional polymer liquid crystal alignment layer of the present invention. In particular, by applying heat and an electric field to the optically functional polymer liquid crystal alignment layer, the molecules of the liquid crystal alignment layer are first arranged by the heat and the electric field and then to the liquid crystal alignment layer. The present invention relates to a molecular arranging device and an arranging method of a photofunctional polymer liquid crystal alignment film for rearranging molecules arranged by the electric field by irradiating polarized light of a specific wavelength.

A photofunctional liquid crystal aligning film using a conventional photopolymer as a liquid crystal alignment film is deposited in a trans mode as shown in FIG. 1 by depositing a light functional polymer on a glass substrate on which a transparent electrode of a liquid crystal display is formed. It arrange | positioned in (1) or the cis mode (2), and orientated the liquid crystal by the said mode.

At this time, since the molecules of the photo-functional polymer of the transmode (1) are arranged in a direction perpendicular to the substrate, the liquid crystal molecules are oriented perpendicular to the substrate, and the molecules of the photo-functional polymer of the cis mode (2) are in a direction horizontal to the substrate. By arranging, the liquid crystal is oriented horizontally on the substrate.

However, in order to align the liquid crystal horizontally, the trans mode 1 is switched to the cis mode 2 by the polarized ultraviolet light 3, but when it is left for a long time, the cis mode 2 is switched back to the trans mode 1. There is a problem in that the liquid crystals must be injected before being switched to the trans mode 1 so that the substrates can be arranged horizontally, thereby being subject to time constraints.

Therefore, in order to solve the above problems, the transmode state, which is a stable state of the photofunctional polymer, is arranged on a predetermined surface, and the liquid crystals are arranged horizontally on the plane on which the transmode is arranged.

To this end, the molecules of the liquid crystal alignment layer were rearranged in a trans mode on a predetermined surface by irradiating at least two times while randomly adjusting the angle of incidence of the ultraviolet light polarized on the photofunctional polymer liquid crystal alignment layer.

2 (a) to 3 (c) and 3 (a) to 3 (c) show the molecular arrangement of the photofunctional polymer rearranged by ultraviolet rays polarized in the x-axis and y-axis directions, respectively. The present invention relates to a method for arranging molecules in a conventional liquid crystal alignment film.

2 (a) to 2 (c) show the shapes of the modes that are changed when the ultraviolet rays are linearly polarized in the P direction parallel to the y-axis and irradiated multiplely at arbitrary angles, using coordinates. As shown in FIG. 2 (a), when the polarized light is irradiated parallel to the y-axis among the trans-modes present in a stable state in the liquid crystal alignment layer of the photofunctional polymer, the trans mode (1) ) Absorb ultraviolet light (3) and switch to cis mode (2). The switched cis mode 2 has a shape in which the top of the chromophore is bent in the z-axis as shown in FIG. 2 (b), or the bottom of the chromophore is bent in the x-axis direction. The cis mode 6 is shown, and when it is exposed again to room temperature or light, it returns to the trans mode as shown in FIG. 2 (c). At this time, the probability of returning molecules in the trans mode to the normal or original direction to the polarized light is about 50%.

Accordingly, continuous irradiation of ultraviolet rays polarized in the same direction arranges molecules of the transmodal photofunctional polymers existing only on the plane perpendicular to the light polarized in the P direction, that is, on the x-z plane.

However, since the transmodes that existed in the direction perpendicular to the polarized light from the beginning are not affected by the polarized ultraviolet rays, they tend to align the liquid crystal molecules vertically, resulting in defects in the alignment of the liquid crystal.

Therefore, when irradiated with ultraviolet light polarized at an angle of incidence other than the initial angle of incidence, the molecules of the transmode which were not affected by the polarized light at the initial angle of incidence are also affected. Since it is rearranged on the vertical plane, it is possible to obtain a liquid crystal alignment film of the photofunctional polymer evenly arranged.

3 (a) to 3 (c) show the transmodes 1 which exist only in the yz plane when the polarized light is irradiated in the S direction parallel to the x-axis direction. a) In the transmode (1) present in a stable state in the liquid crystal alignment film of the optical functional polymer, when the polarized light is irradiated parallel to the x-axis, the transmodes (1) present in the state parallel to the x-axis are ultraviolet (3). ) Is converted to the cis mode (2). The switched cis mode 2 has a shape in which the lower end of the chromophore is bent in the z-axis as shown in FIG. 3 (b), or the lower end of the chromophore is bent in the y-axis direction. The cis mode 8 is shown again when exposed to room temperature or visible light. As shown in FIG. 3 (c), the upper or lower end of the chromophore of the converted cis mode is unfolded to return to the trans mode 1. At this time, the probability that the molecules returned to the transmode 1 return to the normal or original direction to the polarized light is about 50%.

At this time, by repeating the above process at least two or more times, it is possible to manufacture a liquid crystal alignment film for an excellent liquid crystal display with a uniform alignment that can maximize the properties of the photofunctional polymer liquid crystal alignment film.

As described above, when the optical functional polymer is used as the alignment layer, the molecules of the liquid crystal alignment layer are arranged in a non-contact manner by controlling only the polarization direction and the light intensity of light emitted from the outside.

At this time, the photofunctional polymer that can be used is a polymer having a molecular structure of azo (Azo-), stilbene (Stilbene-), Cinnamate- (based).

However, according to the conventional method described above, it is difficult to arbitrarily control the orientation of the photofunctional polymer before the external light is incident, and in many cases, it is incomplete to process advertising molecules oriented in a random direction only with the external light. There is this.

Accordingly, in order to solve the above problems, there is an LB method for making and using a Langmuir-Blodgett (LB) film. Since the LB method requires additional LB equipment, the manufacturing process of the liquid crystal alignment film is complicated. It is difficult to control a large area, the number of optical functional polymers per unit area is small, the liquid crystal alignment ability of the optically functional polymer liquid crystal alignment film by the LB method is lowered, there is another problem that there are a lot of restrictions because the polymer is impossible to produce LB film.

Accordingly, in order to solve the above problems, the present invention preferentially arranges molecules of the photofunctional polymer liquid crystal alignment layer by heat and electricity by applying heat and an electric field to the glass substrate on which the transparent electrode and the photofunctional polymer liquid crystal alignment layer are formed. By irradiating a plurality of ultraviolet rays while adjusting the angle of incidence, it is an object to easily and uniformly arrange the molecules of the photofunctional polymer liquid crystal alignment layer.

In order to achieve the above object, the present invention provides a heater capable of mounting a glass substrate on which a liquid crystal alignment film having conductivity is formed, and an electric field applied to the liquid crystal alignment film formed on the glass substrate. And a counter electrode capable of transmitting light irradiated from and a power supply device for supplying power to the heater and counter electrode, and a polarizer for polarizing and irradiating light from the counter electrode.

In addition, the step of applying heat from the heater to the lower portion of the glass substrate on which the liquid crystal alignment film is formed so that the optical functional polymer can be rotated smoothly, and the dipole moment of the molecules to move smoothly by the heat in the direction of the electric field Applying an electric field from a counter electrode provided on top of the photofunctional polymer liquid crystal alignment film to be arranged; and in a state in which an electric field is applied in order that the dipole direction is arranged in the electric field direction to molecules of the photo functional polymer liquid crystal alignment film Is lowered to the initial temperature, and in order to arrange the molecules of the photofunctional polymer liquid crystal alignment film on the vertical plane of the polarized light beam, the power supply of the counter electrode and the heater is cut off, and the ultraviolet light polarized from the top of the counter electrode Photofunctional polymer liquid crystal alignment, including the step of multiple irradiation at an angle It is characterized by arranging molecules of the membrane.

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

4 shows the structure of a device for arranging molecules of a photofunctional polymer liquid crystal alignment layer using heat, an electric field, and polarized ultraviolet rays according to the present invention, and a transparent electrode on the heater 13 that can apply heat and has conductivity. 10) and a glass substrate 9 on which the photofunctional polymer liquid crystal alignment layer 11 is sequentially formed, and a counter electrode capable of applying an electric field 15 to the upper portion of the photo functional polymer liquid crystal alignment layer 11. A power supply device 14 is connected to the counter electrode 16 and the heater 13 to supply power required to generate the electric field 15. At this time, the counter electrode 16 to be installed should be a transparent electrode that can transmit the polarized ultraviolet light (3) irradiated from the outside.

Further, the ultraviolet light 3 polarized in the s direction parallel to the x-axis and the p direction parallel to the y-axis from an upper portion of the counter electrode 16 is disposed at an angle ( ), At least two surveys should be conducted.

5 (a) to 5 (c) show the change of mrl according to the time of glass transition temperature (Tg), electric field intensity (Ep), and light intensity (Ir). 5 (a) is a temperature at which the molecules of the photofunctional polymer can actively move the temperature of the liquid crystal aligning film 11 by heating the heater 13 installed under the glass substrate 9. It is kept for a certain time above the Tg (glass transition temperature). In this case, section A shown in the drawing is a step of increasing the temperature above Tg, and section B and section C increase above Tg to maintain the temperature for a predetermined time, and then show that the temperature of the first liquid crystal alignment film falls below Tg. .

Next, FIG. 5 (b) shows the intensity of the electric field generated by applying a voltage to the transparent counter electrode 16 provided on the liquid crystal alignment layer 11, hereinafter, the intensity of the electric field is Ep. At this time, in the sections A and B shown in the figure, there is no electric field generated by not applying a voltage to the counter electrode, and in the C section, the electric field is generated by the size of a herd.

Next, FIG. 5 (c) shows the size of the polarized ultraviolet rays 3 irradiated onto the liquid crystal alignment layer 11, and the intensity of the polarized rays is represented by Ir. At this time, in the sections A to C shown in the figure, there is no light to be irradiated, and in the section D, an electric field is applied with the size of Ir.

5 (a) to 5 (c) above, the first section A is a section where only the temperature rises without an electric field or irradiated light, and section B also has a temperature without an electric field or beams irradiated. It is a section that rises above Tg and is kept constant. Section C is a section in which the temperature is maintained above Tg while the electric field is applied at the intensity of Ep, and then falls to the initial temperature of the liquid crystal alignment film. Not investigated Next, the D section is a section in which polarized ultraviolet rays are applied for a predetermined time at Ir size at a slight time interval after the application of the electric field without applying the temperature and the electric field.

Next, as shown in FIGS. 6 (a) to 6 (d), the photofunctional polymer according to the temperature Tg and the electric field Ep shown in FIGS. 5 (a) to 5 (c) are applied. 6 (a) shows the random molecular arrangement of the transmodal (1) molecules of the photofunctional polymer in section A, which is fixed at random when the temperature is below Tg. It is.

Next, FIG. 6 (b) shows the movement of random liquid crystal alignment film transmodal (1) molecules in section B where only temperature is elevated above Tg and kept constant. The photofunctional part of the (eg azodie chain) is free to move.

Next, in FIG. 6 (c), the electric field is applied until the temperature is maintained above the Tg for a predetermined time and the temperature is lowered to the temperature of the liquid crystal alignment layer, thereby moving the molecules of the transmode (1) molecules of the liquid crystal alignment layer. It is shown that the dipole moments of the photofunctional portions of the photofunctional polymer molecules are aligned in the direction of the electric field.

Next, FIG. 6 (d) shows the molecular alignment state of the liquid crystal alignment layer in section D, which is the section before the application of the electric field at the initial temperature and the liquid crystal alignment layer is irradiated with light. It is fixedly arranged.

At this time, the angle between the direction of the electric field Ep and the dipole direction of the photofunctional polymer molecule 12 is as shown in FIG.And the polar angle when using the optical functional polymer Cos=It is given by Ep / 3kT.

Where is the mean for the entire photofunctional part Is the electric dipole moment of the photofunctional moiety, k is the Boltzmann constant, and T is the absolute temperature.

As can be seen from the above equation, it can be seen that the alignment of the photofunctional part is made in good proportion to the intensity of the electric field.

As described above, the present invention is to fix the photofunctional portion of the liquid crystal alignment layer molecules in the electric field direction by using heat and an electric field, and irradiates the ultraviolet light polarized from the outside to the liquid crystal alignment layer having the photofunctional portion oriented in the electric field direction. Thus, the photofunctional portion of the photofunctional polymer is placed in a trans mode and rearranged on a plane perpendicular to the polarization direction of light.

Therefore, according to the method of the present invention, molecules of the photofunctional polymer liquid crystal alignment film can be reliably arranged in a predetermined direction, whereby an excellent alignment film for liquid crystal display can be produced.

Claims (8)

An electric field is applied to the substrate on which the transparent electrode and the optical functional polymer liquid crystal alignment film are formed, the heating means for applying heat to the substrate, and the optical functional liquid crystal alignment film on the substrate, and transmits the light irradiated therefrom. Seek comprises a counter electrode, a power supply means for supplying power to the heating means and the counter electrode, and a polarizing means for polarizing and irradiating light from the upper electrode, the molecular arrangement of the photofunctional polymer liquid crystal alignment film. The device of claim 1, wherein the electrode is a transparent material through which light can pass. The optically functional polymer liquid crystal alignment layer of claim 1, wherein the material of the photofunctional polymer liquid crystal alignment layer has a molecular structure of Azo-, Stilbene-, Cinnamate- series. Molecular array device. Applying heat to the photofunctional polymer liquid crystal alignment layer so that the optical functional polymer can perform a smooth rotational movement, and the optical function for arranging the dipole moments of the photo functional polymer liquid crystal alignment layer molecules that are smoothly moved by the heat in the direction of the electric field. Applying an electric field to the polymer liquid crystal alignment layer, and cooling the temperature while the electric field is applied to the photo functional polymer liquid crystal alignment layer so that the dipole moments of the molecules of the photofunctional polymer liquid crystal alignment layer are fixedly arranged in the electric field direction. And irradiating the ultraviolet light polarized from the upper portion of the optical functional polymer liquid crystal alignment film at an arbitrary angle to arrange the molecules of the optical functional polymer liquid crystal alignment film on the vertical plane of the polarized light. Molecular arrangement method of alignment film. The method of claim 4, wherein in the step of applying heat to the optical functional polymer liquid crystal alignment film, the heat applied to the optical functional polymer liquid crystal alignment film is heated to a glass transition temperature or more, the molecular arrangement of the optical functional polymer liquid crystal alignment film Way. 5. The method of claim 4, wherein in the step of applying an electric field to the photofunctional polymer liquid crystal alignment layer, the dipole moments of the molecules of the photo functional polymer liquid crystal alignment layer are aligned in proportion to the intensity of the electric field. Arrangement method. The optically functional polymer according to claim 4, wherein in the step of irradiating the polarized ultraviolet rays to the optically functional polymer liquid crystal alignment layer in multiple times, the molecules of the optically functional polymer liquid crystal alignment layer are arranged in a cis mode or a trans mode. Molecular arrangement method of liquid crystal aligning film. The method of claim 4 or 5, wherein the temperature applied to the photofunctional polymer liquid crystal alignment layer is maintained until the molecules of the photo functional polymer liquid crystal alignment layer are aligned by an electric field. .