TWI486691B - A method of liquid crystal photo alignment - Google Patents

Description

Liquid crystal light alignment method

The invention relates to a method of liquid crystal light alignment.

The liquid crystal panel generally includes two substrates and a liquid crystal layer interposed therebetween, and the liquid crystal panel generates an electric field in the liquid crystal layer by applying a voltage to determine the orientation of the liquid crystal molecules in the liquid crystal layer and control the amount of light transmitted by the incident light, thereby Produce an image display.

The liquid crystal molecules in the liquid crystal layer are initially aligned in a predetermined direction by a photo-alignment method, and the photo-alignment method can form a pre-tilt angle by irradiating ultraviolet light on the alignment layer. However, in liquid crystal light alignment, liquid crystal molecules are often not arranged in a predetermined direction, which affects the accuracy of alignment.

In view of the above, it is necessary to provide a liquid crystal light alignment method, comprising the steps of: providing a first substrate and a second substrate; forming a first alignment film and a second alignment film on the first substrate and the second substrate, respectively; The liquid crystal forms a liquid crystal layer between the first alignment film and the second alignment film; ultrasonic waves are introduced into the liquid crystal layer to eliminate static electricity; and the first alignment film and the second alignment film are exposed using the alignment light.

It is also necessary to provide a liquid crystal light alignment method, comprising the steps of: providing a first substrate and a second substrate; forming a first alignment film and a second alignment film on the first substrate and the second substrate, respectively; Injecting liquid crystal between the first alignment film and the second alignment film and forming a liquid crystal layer; introducing ultrasonic waves into the liquid crystal layer and causing at least part of the liquid crystal to be The liquid crystal is melted into a liquid without affecting the alignment of the first alignment film and the second alignment film; the liquid crystal layer is cooled; and after the liquid crystal layer is cooled, the first alignment film and the second alignment film are exposed using the alignment light.

Compared with the prior art, the method can erase excess static electricity which affects the alignment effect during the liquid crystal light alignment process, and realigns the liquid crystal to improve the alignment accuracy.

2‧‧‧First substrate

21‧‧‧First alignment film

211‧‧‧First side chain

3‧‧‧Liquid layer

31‧‧‧ liquid crystal molecules

33‧‧‧ Static electricity

4‧‧‧second substrate

41‧‧‧Second alignment film

411‧‧‧Second side chain

5‧‧‧Alignment light

6‧‧‧ Ultrasonic device

1 is a flow chart of a liquid crystal light alignment method.

2 is a schematic structural view of a first substrate and a second substrate.

Figure 3 is a schematic illustration of the first exposure using aligning light during the photoalignment process.

Fig. 4 is a schematic view showing the influence of static electricity on liquid crystal molecules after liquid crystal dropping.

Figure 5 is a schematic illustration of the use of ultrasound during the optical alignment process.

Figure 6 is a schematic illustration of the second exposure using aligning light during the photoalignment process.

In liquid crystal panels, liquid crystal molecules are often not completely aligned in a predetermined direction, and the accuracy of alignment is not high. It has been found that liquid crystal molecules in the liquid crystal panel are likely to generate static electricity during the operation of the substrate during the light-aligning process of the liquid crystal panel due to the movement of the robot arm and the movement of the transport belt, and the liquid crystal molecules in the liquid crystal panel may not be expected under the interference of static electricity. The direction of the arrangement affects the accuracy of the alignment. Therefore, it is possible to eliminate the static electricity after the liquid crystal treatment is injected to improve the alignment accuracy.

The present creative embodiment will be further described in detail below with reference to the accompanying drawings.

FIG. 1 is a flow chart of a liquid crystal optical alignment method according to an embodiment of the present invention, the method comprising the following steps:

In the step S201, as shown in FIG. 2, the first substrate 2 and the second substrate 4 are provided. In the embodiment, the first substrate 2 is a TFT Array Substrate, and the second substrate 4 is It is a color filter substrate (Color Filter Substrate).

In step S202, a first alignment film 21 is formed on the first substrate 2, and a second alignment film 41 is formed on the second substrate 4. The first alignment film 21 and the second alignment film 41 are both photoalignment films. In the present embodiment, the first alignment film 21 and the second alignment film 41 are polyimide (PI) films. The first alignment film 21 includes a plurality of first side chains 211, and the second alignment film 41 includes a plurality of second side chains 411, and the first side chain 211 and the second side chain 411 are in alignment light. The illumination is arranged in a specific direction such that liquid crystal molecules adjacent thereto are aligned in the same direction as the first side chain 211 and the second side chain 411.

In step S203, as shown in FIG. 3, the first alignment film 21 and the second alignment film 41 are exposed using the alignment light 5 . Specifically, the alignment light 5 is ultraviolet (UV) light. In this embodiment, the alignment light 5 has a wavelength of not more than 400 nm. The alignment light 5 is irradiated with the first alignment film 21 and the second alignment film 41 at a certain inclination angle, and the first side chain 211 of the first alignment film 21 and the second side chain 411 of the second alignment film 41 are The alignment light 5 is collectively tilted to the same angle as the illumination angle of the alignment light 5.

In step S204, as shown in FIG. 4, liquid crystal dropping is performed after the exposure is completed. Specifically, liquid crystal is dropped on the surface of the second alignment film 41 to form a liquid crystal layer 3. It is understood that liquid crystal may also be dropped on the surface of the first alignment film 21. The liquid crystal layer 3 includes a plurality of liquid crystal molecules 31 and a plurality of reactive monomers (Reactive Mesogen, RM) formed in the liquid crystal layer 3 in a doped form, the reactive monomers being illuminated It can be polymerized and hardened to assist in stable alignment. After the liquid crystal dropping is completed, the first substrate 2 and the second substrate 4 are pasted, and the first alignment film 21 of the first substrate 2 and the second alignment film 41 of the second substrate 4 are surface-to-face bonded, thereby The liquid crystal layer 3 is interposed between the first substrate 2 and the second substrate 4. More specifically, the liquid crystal layer 3 is located between the first alignment film 21 and the second alignment film 41.

In step S205, as shown in Fig. 5, the liquid crystal layer 3 is melted using ultrasonic waves to eliminate static electricity. Specifically, ultrasonic waves are introduced into the liquid crystal layer 3 by an ultrasonic device 6. The energy generated by the cavitation of the ultrasonic waves in the liquid causes the liquid crystal layer 3 to heat up. When the first alignment film 21 and the second alignment film 41 are higher than a certain temperature, such as 100 degrees Celsius, a reversible reaction occurs to restore the first side chain 211 and the second side chain 411, but The liquid crystal melting point temperature is usually around 70 degrees, which is lower than the temperature required for the reversible reaction to occur. Therefore, when the liquid crystal temperature is controlled between the melting point temperature of the liquid crystal and the initial temperature of the reversible reaction of the alignment film, such as 70 degrees Celsius or more and 100 degrees Celsius or less, the liquid crystal is melted from the liquid crystal into a liquid without affecting the first alignment film 21 and the second. The alignment of the alignment film 41. At the same time, the static electricity 33 deposited on the first substrate 2 and the second substrate 4 is removed from the liquid crystal layer 3 by the action of ultrasonic waves. Preferably, the frequency of the ultrasonic waves does not exceed 5 MHz; in order to completely leak the accumulated static electricity 33, the ultrasonic waves are continuously introduced into the liquid crystal layer for 3 to 10 minutes.

Step S206, the liquid crystal is cooled to below the melting point to form a liquid crystal. At this time, since the static electricity in the first substrate 2 and the second substrate 4 has been eliminated, the liquid crystal molecules 31 are on the first side chain 211 and the second side. The chain 411 is realigned under the action of the chain 411.

As shown in FIG. 6, the liquid crystal layer 3 is again exposed by using the alignment light 5, and the reactive monomer in the liquid crystal layer 3 is polymerized and cured under the action of light, and the liquid crystal molecules 31 in the liquid crystal layer 3 are stably aligned.

It is to be understood that in the present embodiment, the processes of pre-treatment and sintering of the first alignment film 21 and the second alignment film 41 may be included, and are well-known in the art, and are not described herein again. In the present creation, the liquid crystal is melted by ultrasonic waves to quickly remove static electricity that affects the alignment of the liquid crystal, so that stable liquid crystal alignment can be obtained.

In summary, the creation meets the requirements of the invention patent, and the patent application is filed according to law. However, the above description is only a preferred embodiment of the present invention, and the scope of the present invention is not limited to the above embodiments, and those skilled in the art will be equivalently modified or changed according to the spirit of the present invention. It should be covered by the following patent application.

2‧‧‧First substrate

21‧‧‧First alignment film

211‧‧‧First side chain

3‧‧‧Liquid layer

33‧‧‧ Static electricity

4‧‧‧second substrate

41‧‧‧Second alignment film

411‧‧‧Second side chain

6‧‧‧ Ultrasonic device

Claims (14)

A liquid crystal light alignment method comprising the steps of: providing a first substrate and a second substrate; forming a first alignment film and a second alignment film on the first substrate and the second substrate; respectively injecting liquid crystal to be in the first alignment Forming a liquid crystal layer between the film and the second alignment film, the liquid crystal layer comprising a plurality of liquid crystal molecules and a plurality of reactive monomers; passing ultrasonic waves into the liquid crystal layer to eliminate static electricity; using alignment light to the first alignment film and The second alignment film is exposed to polymerize and cure the reactive monomer. The liquid crystal light alignment method according to claim 1, wherein the ultrasonic wave has a frequency of not more than 5 MHz. The liquid crystal light alignment method according to claim 2, wherein the ultrasonic wave is continuously supplied into the liquid crystal layer for 3 to 10 minutes. The liquid crystal light alignment method according to claim 1, wherein the first alignment film and the second alignment film are respectively formed on the first substrate and the second substrate, and the alignment light pair is used before the liquid crystal is injected. The first alignment film and the second alignment film are exposed. The liquid crystal light alignment method according to claim 1, wherein the liquid crystal layer is cooled after the ultrasonic wave is introduced into the liquid crystal layer and before the first alignment film and the second alignment film are exposed by using the alignment light. To normal temperature. The liquid crystal photoalignment method according to claim 1, wherein the first alignment film and the second alignment film comprise a polyimide film. The liquid crystal light alignment method according to claim 1, wherein the alignment light is ultraviolet light, and the ultraviolet light wavelength does not exceed 400 nm. A liquid crystal light alignment method comprising the steps of: providing a first substrate and a second substrate; forming a first alignment film and a second alignment film on the first substrate and the second substrate; respectively injecting liquid crystal to be in the first alignment Forming a liquid crystal layer between the film and the second alignment film, the liquid crystal layer comprising a plurality of liquid crystal molecules and a plurality of reactive monomers; passing the ultrasonic waves into the liquid crystal layer and causing at least part of the liquid crystal to be melted from the liquid crystal into a liquid without Affecting the alignment of the first alignment film and the second alignment film; cooling the liquid crystal layer; and exposing the first alignment film and the second alignment film using the alignment light after the liquid crystal layer is cooled to polymerize and cure the reactive monomer. The liquid crystal light alignment method according to claim 8, wherein the ultrasonic wave has a frequency of not more than 5 MHz. The liquid crystal light alignment method according to claim 9, wherein the ultrasonic wave is continuously supplied into the liquid crystal layer for 3 to 10 minutes. The liquid crystal light alignment method according to claim 8, wherein the first alignment film and the second alignment film are respectively formed on the first substrate and the second substrate, and the alignment light pair is used before the liquid crystal is injected. The first alignment film and the second alignment film are exposed. The liquid crystal light alignment method according to claim 8, wherein the liquid crystal layer is cooled to a normal temperature after the ultrasonic wave is stopped. The liquid crystal photoalignment method according to claim 8, wherein the first alignment film and the second alignment film comprise a polyimide film. The liquid crystal light alignment method according to claim 8, wherein the alignment light is ultraviolet light, and the ultraviolet light wavelength does not exceed 400 nm.