JP3731883B2 - Alignment layer forming apparatus and alignment layer forming method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus and method for forming a liquid crystal alignment layer by ion beam or atom beam irradiation.
[0002]
[Prior art]
In a liquid crystal display device (LCD), an alignment layer is provided in order to align the alignment of liquid crystals. It is known that a liquid crystal alignment layer can be formed by irradiating a thin film formed of polyimide or an inorganic material with an ion beam. The alignment layer is formed by cutting the interatomic bond of the thin film with an ion beam.
[0003]
The liquid crystal alignment direction needs to be uniform throughout the alignment layer. If it is not uniform, it will cause uneven brightness and color of the liquid crystal panel. In order to manufacture a high-quality liquid crystal panel, a more uniform liquid crystal alignment direction is required than ever before.
[0004]
In order to obtain a uniform orientation, it is necessary to make the density distribution of the ion beam emitted from the ion source uniform. The ion beam density has been made uniform by controlling the generation density of gas and free electrons in the plasma generation chamber. However, it is not always easier than various experimental results.
[0005]
As shown in FIGS. 5A and 5B, the surface of the thin film 26 is subjected to molecular processing effective for liquid crystal alignment by irradiating the ion beam 28 while moving the glass substrate 24 at a constant speed. Ideally, in order to perform molecular processing for alignment in a uniform direction over the entire surface, ions are irradiated as beams parallel to each other.
[0006]
The ion source for generating the ion beam 28 is provided with a plate-like body 11c made of a plurality of conductive materials as shown in FIG. In the specification, the plate-like body is referred to as a grid. A plurality of ion ejection ports 30 having the same size are provided in the grid 11c.
[0007]
However, in actuality, the ion beam 28 coming out from each exit 30 of the grid 11c has a certain spread. Therefore, the mask 20 having the slits 22 is provided above the substrate 24 on which the thin film 26 is applied. As described above, since the ion beam 28 has a certain spread, the excess ion beam 28 is cut by the mask, in other words, only the ion beam 28 desired to contribute to the formation of the alignment layer is irradiated to the thin film 26. When the ion beam intensity distribution in the Y direction shown in FIG. 5B is not uniform, the alignment direction may be nonuniform in the alignment processed thin film 26.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide an apparatus and a method for making the alignment direction of an alignment layer uniform when forming a liquid crystal alignment layer by ion beam irradiation.
[0009]
[Means for Solving the Problems]
The gist of the alignment layer forming apparatus of the present invention includes an ion source for irradiating ions to a thin film on a substrate, and the ion source includes a grid provided with a plurality of ion ejection openings having different sizes. The size of the injection port is changed according to the ion density. The ion beam intensity becomes uniform, and the liquid crystal alignment direction can be made uniform.
[0010]
A grid in which the size of the ion injection port is the same and the number of the injection ports per unit area is different may be used. The number of injection ports varies depending on the ion density. Even with such a grid, the ion beam intensity becomes uniform, and the liquid crystal alignment direction can be made uniform.
[0011]
The gist of the alignment layer forming method of the present invention is to generate an ion beam with an ion source, to make the ion beam uniform according to the ion density, and to irradiate the thin film on the substrate with the uniformed ion beam. Including the steps of: The step of making uniform is made uniform by the ion outlet of the plate-like body in the ion source. At a position where the ion density is high, the size of the ion ejection openings is made smaller than that at a low position and / or the number of ion ejection openings per unit area is reduced.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of an alignment layer forming apparatus and method of the present invention will be described with reference to the drawings.
[0013]
In the present invention, as shown in FIGS. 1A and 1B, a mask 20 is disposed between an ion source 12 and a glass substrate 24 coated with a thin film 26 for liquid crystal alignment. The mask 20 has a slit 22. A table (not shown) on which the glass substrate 24 is placed and moved is included. The grid 11a of the ion source 12 is provided with a plurality of ion injection ports 30 as shown in FIG.
[0014]
The ion source 12 includes a plasma generation chamber 16, a gas introduction port 14 for sending gas into the plasma generation chamber 16, an acceleration electrode 18 for accelerating ions generated in the plasma generation chamber 16, and ions for extracting the accelerated ions to the outside. And a grid 11a including an injection port. For example, argon (Ar) gas is used as the gas. In the case of argon gas, argon ions (Ar ⁺ ) are generated in the plasma generation chamber 16.
[0015]
The injection port 30 provided in the grid 11a will be described. The ion intensity distribution in the Y direction in FIG. 1B is affected by the amount of plasma generated in the plasma generation chamber 16. FIG. 2 shows the ion intensity distribution when there are two gas inlets. In FIG. 2, the ionic strength is expressed as a relative current density. When the ionic strength is high, the ion density is high. The horizontal axis in FIG. 2 is the position of the ion source 12 in FIG. 1 in the Y direction. As shown in FIG. 2, various causes of peaks and valleys are conceivable. For example, the position of the gas inlet may be considered as the cause. Even if the number of gas inlets is increased or slitted, and the gas flow rate is adjusted, the ion intensity distribution becomes non-uniform due to various other reasons, and the structure related to the gas inlet becomes complicated. The ionic strength distribution cannot be made uniform.
[0016]
Therefore, as shown in FIG. 3, the grid 11 a has a plurality of injection ports 30 and have different sizes. The size of the injection port 30 varies depending on the ion density at each position of the grid 11a. As the ion density decreases, the size of the injection port 30 is increased. Therefore, the injection port 30 is the smallest at the position where the ion density is the highest, and the injection port 30 is the largest at the position where the ion density is the lowest. The shape of the injection port 30 is arbitrary, such as a circle, an ellipse, and a polygon.
[0017]
In the ionic strength distribution of FIG. 2, the above configuration has a small injection port 30 where the current density is high and a large injection port 30 where the current density is low. Therefore, the intensity distribution of the irradiated ion beam becomes uniform. The size of the injection port 30 is, for example, 3 mm in diameter at the largest and 2.5 mm in diameter at the smallest.
[0018]
The orientation direction at a certain point on the thin film 26 is most influenced by the direction of the ion beam 28 incident last on the point. Therefore, it is not always necessary to change the size of the injection port 30 with respect to the entire surface of the grid 11a.
[0019]
Therefore, the grid 11a includes a region 34a having the injection ports 30 having different sizes and a region 32a having the injection ports 30 having the same size. The two regions 32a and 34a are arranged in parallel to the direction of the slit 22 (longitudinal direction of the slit 22 (Y direction in FIG. 1B)). The two regions 32a and 34a arranged side by side are provided with regions 34a having injection ports 30 of different sizes on the lower side in the direction of movement of the substrate 24, that is, on the side where any one point of the substrate 24 finally passes. In FIG. 1, a region 34a is provided at a position on the right side of the grid 11a.
[0020]
In the alignment layer forming method, a substrate 24 provided with a thin film 26 such as polyimide is placed on a table. While moving the stage, the thin film 26 is irradiated with the ion beam 28 through the slit 22. The ion beam 28 is emitted from the exit 30 described above. The interatomic bond of the thin film 26 is cut by the ion beam 28 to form an alignment layer.
[0021]
To summarize the present invention, the size of the injection port 30 is changed based on the ion density at each position of the grid 11a. That is, the intensity of the ion beam from the ion source 12 is made uniform by reducing the exit 30 at a position where the ion density is high and increasing the exit 30 at a position where the ion density is low.
[0022]
The above-described processing of the injection port 30 does not need to be performed on the entire surface of the grid 11a, and is performed only on the side through which the glass substrate 24 passes in the latter half or the last.
[0023]
The ion beam 28 emitted from each point of the ion source 12 has a three-dimensional spread angle in which the number of particles (ions) traveling vertically from the plane of the grid 11a is the largest and the number gradually decreases concentrically. Head to 24. When this is viewed from the substrate 24 side, particles whose particle trajectory has a Y-direction component in FIG. 1B, that is, particles incident at an angle inclined with respect to the traveling direction of the substrate 24 are included.
[0024]
In the region 34a where the size of the injection port 30 changes, the ion beam intensity can be made uniform in the Y direction in FIG. Under this condition, the number of particles irradiated to any one point on the substrate 24 is the largest in the Y direction component in FIG. There will be no orbital particles. That is, the direct rays from the ion source 12 are strongest at each point on the substrate 24, and processing without fluctuation in the orientation direction can be realized.
[0025]
If the Y-direction ion intensity distribution is not uniform, there is a situation in which particles on orbits inclined with respect to the X-axis other than direct rays are strongest in a certain part on the substrate 24.
[0026]
The ion beam intensity may be made uniform by means other than changing the size of the injection port 30. As shown in FIG. 4, the size of the injection port 30 is made constant, and the number of the injection ports 30 per unit area is changed.
[0027]
The number of injection ports 30 varies depending on the ion density at each position of the grid 11b. As the ion density decreases, the number of injection ports 30 per unit area is increased. The grid 11b includes a region 34b having a different number of injection ports 30 per unit area and a region 32b having the same number. The two regions 32 b and 34 b are arranged in parallel to the direction of the slit 22. The two regions 32b and 34b arranged side by side are regions 34b having different numbers of injection ports 30 on the lower side in the moving direction of the substrate 24.
[0028]
Ratio of the injection port 30 per unit area, for example, the most injection port 30 a large number place of nine / cm ^2, 6 pieces at less / cm ^2.
[0029]
By changing the number of the injection ports 30 per unit area and making the injection ports 30 dense, the ion beam intensity distribution is made uniform, and the alignment layers can be aligned.
[0030]
As mentioned above, although embodiment of this invention was described, this invention is not limited to said embodiment. For example, although two areas 32a, 32b, 34a, and 34b are provided in the grids 11a and 11b, one area 34a and 34b may be used.
[0031]
Further, although the embodiment in which the size or density of the injection port 30 is changed has been described above, an aspect in which the size and density are simultaneously changed may be employed. The size and density of the exit port 30 are adjusted so that the ion beam 28 is uniform.
[0032]
The thin film 26 is irradiated with the ion beam 28 from the ion source 12. In addition to the ion beam 28, ions are accelerated to generate the ion beam 28, and then the ion beam 28 is neutralized to generate an atomic beam. May be applied to the thin film 26.
[0033]
In addition, the present invention can be carried out in a mode in which various improvements, modifications, and changes are added based on the knowledge of those skilled in the art without departing from the spirit of the present invention.
[0034]
【The invention's effect】
According to the present invention, the intensity distribution of the ion beam can be made uniform, and the orientation direction of the orientation layer can be made uniform. Therefore, it is possible to manufacture a liquid crystal display device having no brightness unevenness and color unevenness.
[Brief description of the drawings]
1A and 1B are views of an alignment layer forming apparatus of the present invention, in which FIG. 1A is a side view and FIG. 1B is a top view.
FIG. 2 is a graph showing an ion intensity distribution in the Y direction in an ion source.
FIG. 3 is a diagram of a grid used in the alignment layer forming apparatus of the present invention.
FIG. 4 is a diagram of another grid used in the alignment layer forming apparatus of the present invention.
5A and 5B are diagrams illustrating formation of an alignment layer, in which FIG. 5A is a side view and FIG. 5B is a top view.
FIG. 6 is a diagram of a grid used in a conventional alignment layer forming apparatus.
[Explanation of symbols]
10: Alignment layer forming devices 11a, 11b, 11c: Grid (plate-like body)
12: Ion source 14: Gas inlet 16: Plasma generation chamber 18: Accelerating electrode 20: Mask 22: Slit 24: Substrate 26: Thin film 28: Ion beam 30: Ejection port 32a: Region 32b having the same size of the ejection port Region 34a having the same number of injection ports per unit area: Region 32b having different injection port sizes: Region having different numbers of injection ports per unit area

Claims (13)

An ion source for generating an ion beam;
A mask provided between the substrate of the liquid crystal display device and the ion source and having a slit;
An apparatus for forming an alignment layer on a substrate comprising:
An alignment layer forming apparatus, wherein the ion source includes a plate-like body provided with a plurality of ion injection ports having different sizes.   The alignment layer forming apparatus according to claim 1, wherein the size of the ion injection port varies depending on the ion density.   3. The alignment layer forming apparatus according to claim 2, wherein in the plate-like body, an ion ejection port at a position having a high ion density is smaller in size than an ion ejection port at a position having a low ion density.   The alignment layer forming apparatus according to claim 1, wherein the plate-like body includes a region having ion ejection ports having different sizes and a region having ion ejection ports having the same size.   The alignment layer forming apparatus according to claim 4, wherein the two regions are aligned in the slit direction.   The alignment layer forming apparatus according to claim 5, wherein the alignment layer forming apparatus according to claim 5, further comprising an ion injection port having a different size on a lower side in the moving direction of the substrate in the two regions arranged side by side, the table having the stage for moving the substrate. An ion source for generating an ion beam;
A mask provided between the substrate of the liquid crystal display device and the ion source and having a slit;
An apparatus for forming an alignment layer on a substrate comprising:
An alignment layer forming apparatus in which the ion source is provided with a plate-like body having a different number of ion ejection openings per unit area.   The alignment layer forming apparatus according to claim 7, wherein the number of the ion ejection openings varies depending on the ion density.   9. The alignment layer forming apparatus according to claim 8, wherein in the plate-like body, the number of ion ejection openings per unit area at a position where the ion density is high is smaller than the number of ion ejection openings per unit area at a position where the ion density is low. .   The alignment layer forming apparatus according to claim 1, wherein the plate-like body includes a region where the number of ion ejection ports per unit area is different and a region where the number of ion ejection ports per unit area is the same.   The alignment layer forming apparatus according to claim 10, wherein the two regions are arranged in parallel to the slit direction.   The alignment layer forming apparatus according to claim 11, wherein the alignment layer forming apparatus according to claim 11, further comprising: a table having a stage for moving the substrate; A method of forming an alignment layer on a substrate of a liquid crystal display device,
Generating an ion beam with an ion source;
Depending on the level of ion density in the ion source, the size of the plurality of ion emission ports provided in the ion source, the number of ion emission ports per unit area, or both are different, and the ions are emitted from the plurality of ion emission ports. Making the ion beam intensity uniform,
Irradiating the thin film on the substrate with the uniformed ion beam.

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