JP2010078971A - Alignment layer-forming method and rubbing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the following problem: although an in-cell structure for a higher contrast is designed for a retardation film of a reflection type liquid crystal mobile display, an alignment layer as a base becomes easy to repel liquid crystal since the retardation film is made of polymerizable liquid crystal and the liquid crystal is cured by crosslinking, and if the repelling is caused in a reflection area, polarization control at the part ends in failure to cause a large defect. <P>SOLUTION: The alignment layer after being baked in an oven is irradiated with excimer UV and then subjected to rubbing processing to avoid repellence. Using this method reduces electrostatic charging of a substrate during the rubbing as well as avoiding the repellence. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and a rubbing apparatus for forming an alignment film, particularly an alignment film for a retardation film, in the liquid crystal display field.

  An alignment film used for a liquid crystal display has a function of aligning liquid crystals. By aligning the liquid crystal in a certain direction when the voltage is ON or OFF, a phase difference is imparted when light passes, and a black and white display is realized by using a polarizing plate. In addition, color display is realized by using a color filter.

  The alignment film can be aligned with the liquid crystal injected or applied onto the alignment film by rubbing in a certain direction with a cloth or the like. The rubbing process is called a rubbing process.

  The liquid crystal is aligned in the rubbing direction on the alignment film subjected to the rubbing treatment, and the liquid crystal layer is anisotropic.

  When light that has passed through the polarizing plate enters an anisotropic liquid crystal layer at a certain angle, only a light component corresponding to the delayed phase of the liquid crystal produces a phase difference. As a result, the light changes to circularly polarized light or linearly polarized light rotated by 90 °.

  By using the above mechanism, it is possible to control the polarization state of light passing through the liquid crystal in a state where a voltage is applied (ON) and a state where the voltage is not applied (OFF).

  At present, liquid crystal displays are mainly divided into TV applications and mobile applications. In mobile applications, both reflective and reflective parts are used inside the liquid crystal cell to make it easy to see both indoors and indoors, which are relatively dark. It has a complicated structure such as a display function.

  FIG. 1 is a schematic cross-sectional view showing an outline of a layer structure of a normal reflective mobile display. In the reflection part, since the external light from the viewing side passes through the liquid crystal layer and then is reflected by the reflection mirror 6, it passes through the liquid crystal layer twice, so that the liquid crystal cell gap d / 2 serving as the liquid crystal layer is transmitted. The same function as the liquid crystal cell gap d of the portion is achieved. More specifically, the polarizing plate 1 on the viewing side, the color filter 3, the transparent electrode 4 on the viewing side, the liquid crystal alignment film 5 on the viewing side, and the liquid crystal layer all pass twice. The color filter 3 includes a transparent substrate 3a on the viewing side and a colored layer 3b in which pixels are arranged.

  In the reflection type display, the phase difference film 2 on the viewing side is further added to the above layer structure to drive the light with the same phase. In addition, a viewing-facing-side structure in consideration of the transmission part is also necessary, and the viewing-facing-side liquid crystal alignment film 7, the viewing-facing-side transparent electrode 8, the viewing-facing-facing-side transparent substrate 9, and the viewing-facing-facing-side retardation film 10. The main components including the polarizing plate 11 on the side facing the viewer and the backlight 12 installed outside the liquid crystal cell are arranged. Various electrode arrangements are required corresponding to the liquid crystal driving method, but FIG. 1 omits the details of the electrical mechanism and mainly shows the optical components.

  As a disadvantage of the reflective display, it is necessary to sandwich the retardation film above and below the liquid crystal layer, so that the brightness of the transmissive portion is reduced.

  In order to improve the above problem, recently, a method of giving a phase difference only to the reflection part has been devised. In this method, a phase difference film made of a polymerizable liquid crystal is applied to a color filter, and is patterned using a patterning technique so that a phase difference appears only in the reflection part. It is characterized in that it is formed on the side and made in-cell. The layer structure is shown in FIG.

  FIG. 2 is a schematic cross-sectional view showing an outline of a layer structure of a reflective mobile display in which a retardation film is in-celled. 1 does not include the phase difference film 2 on the viewing side and the phase difference film 10 on the side facing the viewing side, and instead is anisotropic in a position corresponding to the reflective portion on the inner surface side of the liquid crystal cell of the color filter 3. A retardation film 14 is formed. As will be described later, the isotropic retardation film 15 formed at a position corresponding to the transmission part is a result of removing the function as the retardation film, and can be removed as a substance. Further, as a means for forming the retardation film, it is necessary to previously form the alignment film 13 for the retardation film on the color filter.

  As a method of giving a phase difference only to the reflection portion, there are a method of developing and removing the retardation film of the transmission portion by a photolithography method, and a method of forming only by exposure and baking without requiring a development step.

  The former is a technique that selectively removes the retardation film in the transmissive part by exposure and development patterning means, and the latter is after anisotropy is achieved by orienting a polymerizable liquid crystal having no development solubility on the alignment film. , Only the polymerizable liquid crystal at the position corresponding to the reflective portion is cured by exposure to fix the anisotropy, while the polymerizable liquid crystal at the position corresponding to the unexposed transmission portion returns to the isotropic phase upon firing. Is adopted.

  In either technique, it is not necessary to sandwich the retardation film having the original anisotropy at the transmission part, so that the transmission of light is not hindered. Therefore, the characteristic of improving the brightness of the transmissive part is obtained, which contributes to the improvement of contrast.

  Further, as will be described later, the contrast of the reflective portion can be improved by adopting the technology of retardation film in-cell.

  Originally, the retardation film mainly corrects the phase difference of λ / 4 with respect to the wavelength λ of the light, but the pixel of the color filter display generates light of each wavelength such as red, blue, and green. Therefore, the most appropriate retardation film is different. That is, since red has a long wavelength, it is desirable to use a retardation film for a long wavelength, and conversely, blue has a short wavelength, so that a retardation film for a short wavelength is used.

  In the method of sandwiching a normal retardation film, it is assumed that the same retardation film is used for all pixels of red, blue, and green. However, by forming the phase difference film in-cell and forming a phase difference film corresponding to the color of each pixel of the reflection portion, the effect of correcting the phase difference is optimized and the contrast of the reflection portion can be improved. The phase difference film corresponding to the color of each pixel of the reflection unit is a layer that adds gradation to the phase difference of the red pixel, the blue pixel, and the green pixel.

  As a method of adding gradation to the retardation film, a method of changing the film thickness at each pixel, or by controlling the exposure amount, gradation is applied to the polymerizable property of the polymerizable liquid crystal constituting the retardation film. As a result, there is a method of adding gradation to anisotropy.

  With the recent increase in image quality demand for mobile displays, there is an increasing demand for contrast enhancement by in-cell retardation film technology. In order to manufacture the anisotropic retardation film 14 with high quality, it is necessary to previously form the alignment film 13 for retardation film with high quality on the color filter as described above. .

  The retardation film described above is made of a polymerizable liquid crystal, but an alignment film is required as a base in order to provide anisotropy in the same manner as a normal liquid crystal material for driving. For the alignment film, polyimide (PI) is mainly used, and the polymerizable liquid crystal applied thereon is aligned by a process called rubbing.

  However, normal liquid crystal materials for driving are encapsulated in an uncured, low-viscosity, highly liquid material, whereas polymerizable liquid crystals are gradually cured by light and heat during the formation process. Then, repelling occurs due to in-plane flow of the liquid crystal material. When the polymerizable liquid crystal agent applied on the alignment film is repelled, the portion loses anisotropy at all and becomes a serious defect that makes it impossible to control the deflection of light.

  Further, since the rubbing process is a dry process in which the substrate is rubbed with a cloth or the like, the substrate to be rubbed is easily charged. There is a problem that dust is likely to adhere to the charged substrate. Although the rubbing apparatus is often accompanied by an ionizer for removing the charge, it is still not a sufficient charge removal measure.

On the other hand, many proposals have been made regarding surface treatment methods for semiconductor substrates and liquid crystal display substrates, and devices have been devised to increase the cleanliness of the substrate surface by irradiating the substrate with ultraviolet rays (see Patent Document 1). Among these, light having a wavelength of 100 to 200 nm called vacuum ultraviolet light is larger than the interatomic bonding force of most substances and can directly break the bond. In recent years, excimer lamps using a rare gas typified by Xe (xenon) gas have been put into practical use, and applied to surface treatment techniques such as substrate cleaning.
JP 2001-300454 A

  The problem to be solved by the present invention is to realize a high cleanliness on the surface of the alignment film used in the liquid crystal display element, to form a uniform alignment film free from cissing, etc., and to provide a high quality for the rubbing process and subsequent processes. It is providing the method for providing a member, and the rubbing apparatus for implement | achieving it. In particular, it is intended to achieve high cleanliness on the surface of the alignment film for forming an anisotropic retardation film made of polymerizable liquid crystal, so that the anisotropic retardation film does not cause defects due to repelling. To do.

  The invention according to claim 1 is a method for forming an alignment film used for a liquid crystal display element, wherein the alignment film is irradiated with UV (ultraviolet rays) after being applied and baked and before rubbing. This is a film forming method.

  The invention according to claim 2 is the alignment film forming method according to claim 1, wherein the alignment film is an alignment film for a retardation film.

  The invention according to claim 3 is the alignment film forming method according to claim 1 or 2, wherein the ultraviolet ray to be irradiated is a UV irradiation method having a peak in a vacuum ultraviolet region having a wavelength of 100 to 200 nm. It is.

  The invention according to claim 4 is an excimer UV irradiation method using Xe (xenon) gas having a peak at a single wavelength near 172 nm. The alignment film forming method according to any one of the above.

Further, Claim invention of claim 5, in excimer UV irradiation system using the Xe gas, the quantity of ultraviolet light to be irradiated, characterized in that in the range of 10mJ / cm ² ~200mJ / cm ² 4. An alignment film forming method according to 4.

  The invention described in claim 6 is characterized in that, in the excimer UV irradiation method using the Xe gas, the distance between the UV irradiation window surface and the substrate surface to be irradiated is in the range of 1 mm to 5 mm. 4. The alignment film formation method according to 4 or 5.

  The invention described in claim 7 is an apparatus used when forming a liquid crystal alignment film or a film having orientation by rubbing, and comprises means for irradiating UV (ultraviolet light) before rubbing treatment of the film. It is a rubbing device.

  The invention according to claim 8 is the rubbing apparatus according to claim 7, characterized in that the ultraviolet rays to be emitted are emitted from UV irradiation means having a peak in a vacuum ultraviolet region having a wavelength of 100 to 200 nm.

  The invention according to claim 9 is characterized in that the ultraviolet rays to be emitted are emitted from an excimer UV irradiation means sealed with Xe (xenon) gas having a peak at a single wavelength near 172 nm. The rubbing apparatus described in 1.

  The invention according to claim 10 is characterized in that, in the excimer UV irradiation means in which the Xe gas is sealed, the distance between the UV irradiation window surface and the irradiated substrate surface can be set in a range of 1 mm to 5 mm. 9. The rubbing apparatus according to 9.

  Since this invention is the above structure, there exist the following effects. That is, according to the invention according to claim 1, after the alignment film is applied and baked, the surface of the alignment film is modified and hydrophilized by irradiating with ultraviolet rays before the rubbing process. Thus, a sufficient rubbing effect can be imparted to the alignment film. Further, since the charge due to rubbing of the alignment film surface is also reduced by the prior ultraviolet irradiation, dust removal due to the charge can be avoided, so that a high quality member can be provided.

  Further, according to the invention according to claim 2, when the alignment film is baked and irradiated with ultraviolet rays before the rubbing treatment, an additive that bleeds out (bleeds out) from the alignment film to the outermost surface of the alignment film is selected. In particular, ultraviolet rays act, and additives such as a leveling agent for improving coatability are not required after coating, and the additive can be removed by oxidation or hydrophilicized. As a result, the rubbing process can be performed in a state in which the orientation inhibiting factor is removed, and a more efficient rubbing process is realized. In particular, in an alignment film for a retardation film, since it is often a relatively thick film having a flattening function, the influence of an additive that bleeds out to the outermost surface of the alignment film cannot be ignored. An effect can be obtained. In addition, since the influence on the polymerizable liquid crystal that is likely to cause repelling in the coating process after rubbing is more severe than the influence on the normal driving liquid crystal material, the effect is also remarkable.

  Further, according to the invention according to claim 3, ultraviolet rays having an intensity peak in the vacuum ultraviolet region are larger than the interatomic bonding force of most substances and can directly break the bond. The aforementioned surface modification effect described above can be obtained efficiently and reliably.

Further, according to the invention of claim 4, if Xe excimer UV irradiation having a single wavelength near 172 nm is used, active species “O.”, “O ₃ ”, “HO” required for surface modification are used. "" Can be generated efficiently and can be used most stably. That is, there is a feature that the surface modification reaction is accelerated only in the vicinity of the surface of the substrate to be irradiated with little damage to the entire substrate to be irradiated with ultraviolet rays.

Further, according to the invention according to claim 5, the amount of ultraviolet rays to be irradiated, by irradiating in a range of ^{10mJ / cm 2 ~200mJ / cm 2} , no substrate damage, better surface modification, i.e. This can be done while avoiding repelling. If it is less than 10 mJ / cm ² , the effect on repelling is low, and if it exceeds 200 mJ / cm ² , the rubbing effect decreases.

  According to the invention relating to claim 6, in the excimer UV irradiation method using Xe gas, the distance between the UV irradiation window surface and the irradiated substrate surface is in the range of 1 mm to 5 mm. As a result, as the irradiation window surface and the surface of the substrate to be irradiated are separated from each other, the ultraviolet light is rapidly attenuated due to atmospheric absorption to prevent the effect of reducing the surface modification effect, and conversely, the distance is too close to the irradiation window surface. It is possible to avoid the possibility that the substrate to be irradiated comes into contact and the non-uniform surface modification effect.

  Moreover, according to the invention concerning Claims 7-10, UV irradiation is provided by providing the practical production apparatus for implementing the alignment film formation method described in the above-mentioned Claims 1-6 as a rubbing apparatus. It is possible to obtain an integrated means for reliably and stably performing the rubbing process, stabilize the process, and provide a high-quality member.

  Hereinafter, an alignment film forming method and a rubbing apparatus according to the present invention will be described based on embodiments thereof.

  FIG. 3 is a line configuration diagram for explaining the alignment film forming method of the present invention, and is a diagram briefly showing the flow of each process from alignment film coating, baking, ultraviolet irradiation, and rubbing. Reference numeral 16 denotes a coating apparatus, 17 denotes an oven for baking, 18 denotes a rubbing apparatus, and 19 denotes a UV irradiation means. The processing substrate is passed in the direction of an arrow 20. The coating device 16 can be appropriately selected depending on conditions such as the material and thickness of the coating film, and can be achieved by spin coating, die coating, curtain coating, flexographic printing, gravure printing, inkjet coating, and the like. The oven 17 may be a batch type heat circulation type or a hot plate type, and they are used properly according to conditions from drying to baking. The rubbing device 18 may be a general one having a rotary rubbing cloth mechanism, a substrate feed stage, and a function of adjusting their position and angle.

  An excimer UV irradiation device can be disposed as the UV irradiation means 19 between the baking oven and the rubbing device, but the excimer UV irradiation device may be provided in the baking oven or the rubbing device. However, it is more preferable to provide in the rubbing apparatus because the conditions up to rubbing can be easily maintained. In the present invention, it is essential to perform UV irradiation after baking the alignment film and before starting the rubbing of the alignment film. In the UV irradiation before firing of the alignment film, bleedout of additives and the like from the alignment film occurs by baking after UV irradiation, and the effect of surface modification becomes insufficient. Further, the UV irradiation after the rubbing process causes damage in a direction that cancels the effect of the rubbing process itself.

As the UV irradiation means 19, an excimer UV lamp using Xe gas having a single wavelength peak of 172 nm is desirable. When employing an excimer UV lamp using Xe gas is preferably set to 10mJ / cm ² ~200mJ / cm ² about the irradiation light amount. If the amount is too small, the effect of irradiation cannot be sufficiently obtained. If the amount is too large, not only is the energy efficiency poor, but an excessive surface modification effect is excessively caused to cause damage to the surface. In addition, the distance between the UV irradiation window surface and the irradiated substrate surface at this time is suitably in the range of 1 mm to 5 mm. As the irradiation window surface and the surface of the substrate to be irradiated are separated from each other, ultraviolet rays are rapidly attenuated due to atmospheric absorption and the surface modification effect is reduced. Therefore, the surface modification effect is reduced to 5 mm or less. The distance of 1 mm or more is maintained in order to avoid the possibility of contact with the substrate and non-uniform surface modification effects.

As the UV irradiation means 19, a low-pressure mercury lamp including 185 nm and 254 nm may be mounted. When employing a low pressure mercury lamp is preferably about 100mJ / cm ² ~1000mJ / cm ² irradiation amount, because it is not sensitive surface modification effect with regard irradiation distance, the range of 10mm~100mm is appropriate.

When excimer UV using Xe gas is irradiated, an oxygen concentration of about 4% has the highest surface modification effect. Therefore, there is a method of providing an N ₂ gas supply slit 21 shown in FIG. However, the amount 10mJ / cm ² ~200mJ / cm ² presented in claim 5 is a condition under air atmosphere, in the case of adjusting the oxygen concentration, the amount of light it is necessary to adjust from time to time.

The rubbing apparatus for carrying out the alignment film forming method of the present invention is an apparatus used when forming a liquid crystal alignment film or a film having alignment properties by rubbing, and UV (ultraviolet light) before rubbing treatment of the film. It is a rubbing apparatus provided with the means to irradiate. The number of lamps to be irradiated with UV and the illuminance specific to the lamp are not particularly limited, but in the case of excimer UV irradiation means using Xe gas, the amount of ultraviolet light to be irradiated is 10 mJ / cm ^{2 to} 200 mJ / cm ^2. It is desirable to select and mount the lamp and the number so that the amount of irradiation light can be secured. In addition, the light quantity can be adjusted at the conveyor conveyance speed under the UV irradiation means, and the number of UV lamps to be turned on can be arbitrarily set.

  Excimer UV lamps cause a decrease in illuminance over time. Therefore, it is desirable that the illuminance of the excimer UV lamp can be monitored at all times, and the attenuated amount can be automatically fed back by adjusting the lamp output. In addition, the light receiver that measures illuminance also deteriorates with time, and correct illuminance cannot be calculated. It is necessary to replace the light receiver at a frequency of once / year or more. The mechanism of illuminance monitoring is shown in the structure explanatory diagram of the excimer UV lamp in FIG.

  In FIG. 4, reference numeral 24 denotes a UV reflecting mirror that reflects the UV irradiated upward from the UV lamp 25 and is uniform toward the UV irradiation window 26 provided on the substrate side together with the direct light from the UV lamp 25. Irradiate. Further, 22 is a light receiver, 23 is a light receiving portion, and 23 has a structure in which a hole is formed in the reflection mirror.

  The excimer UV irradiation means using Xe (xenon) gas having a single wavelength near 172 nm among the UV irradiation means explaining the embodiments of the present invention is the most common among excimer UV lamps using various rare gases. In general, rare gas excimer UV lamps emit light having a wavelength of 100 to 200 nm called vacuum ultraviolet light. It is generally known that the energy of vacuum ultraviolet light is larger than the interatomic bonding force of most substances and can be directly broken, so that it is suitable as a means for surface treatment. In the method of forming an alignment film used for a display element, it is proposed that it is effective to perform surface modification by excimer UV irradiation before rubbing the coated and baked alignment film.

  Hereinafter, a specific operation method according to the embodiment will be described. The flow from coating and baking of the alignment film to rubbing is as shown in FIG. 3 described above. In the examples, each device is a single evaluation device, and each process is processed by hand conveyance. did.

  The alignment film for the retardation film is formed on the color filter as indicated by 13 in FIG. However, the actual color filter surface is not flat as shown in FIG. Since the unevenness causes a problem in the characteristics of the retardation film 14 shown in FIG. 2, it was used as a planarizing alignment film having both functions of the planarizing film and the alignment film.

  A planarizing alignment film was applied to the color filter by spin coating, dried under reduced pressure at an ultimate pressure of 133 Pa, and then pre-baked at 90 ° C. for 60 seconds. A hot plate was used for pre-baking. After pre-baking, firing was performed at 200 ° C. for 60 minutes in a heat-circulating oven.

After the firing, a Xe excimer UV at 172nm single wavelength and 70 mJ / cm ² irradiation at gap 2 mm, 10min washed with pure water ultrasonic before performing the rubbing process. The rubbing conditions were a rubbing cloth rotation speed of 500 rpm and a feed speed of 50 mm / sec.

  Thereafter, it was again washed with pure water for 10 minutes, and the polymerizable liquid crystal was applied by spin coating, dried under reduced pressure, and pre-baked under the same conditions as the planarizing alignment film. The polymerizable liquid crystal material was not a developer-soluble material, but a material whose gradation was controlled by the exposure amount. The oven treatment was also performed under the same conditions as the planarized alignment film, and the presence and orientation of repelling were confirmed.

  As a result of confirming the sample produced by the above process, no repelling was confirmed, and there was no problem in the orientation. On the other hand, it was also confirmed that repellency occurred frequently in the sample without the excimer UV treatment produced as a reference.

FIG. 5 shows the relationship between the amount of excimer UV applied to the planarizing alignment film and the contact angle of water. The water contact angle was displayed in arbitrary units. It can be seen that when the irradiation amount is increased, the contact angle is lowered and the surface modification is progressing. It can be seen that a steady state is reached at about 80 mJ / cm ² .

FIG. 6 shows the relationship between the black luminance indicating the orientation and the excimer UV irradiation amount. The black luminance is a value of the liquid crystal cell reflection portion and is displayed in an arbitrary unit. If the alignment state of the anisotropic retardation film made of a polymerizable liquid crystal is good, the black luminance should be low, but in this example, the black luminance suddenly increased at an irradiation amount of 80 mJ / cm ² or more. This shows that the orientation deteriorates. FIG. 6 shows at least the dependence of the excimer UV dose on the alignment film performance.

The excimer UV resistance varies depending on the planarization alignment film or the material of the alignment film. The planarization alignment film used this time was 80 mJ / cm ² as the UV irradiation amount, and neither repelling nor poor alignment occurred.

  As described above, the alignment film used for the liquid crystal display element, in particular, the surface of the alignment film for forming the anisotropic retardation film made of polymerizable liquid crystal realizes high cleanliness, and the anisotropic retardation film It was confirmed that no defect caused by repelling occurred. As a result, the present invention can provide a method for forming a uniform alignment film free from repelling, etc., and providing a high-quality member for the rubbing process and subsequent processes, and a rubbing apparatus for realizing the method. There was found.

It is a cross-sectional schematic diagram which shows the layer structure outline | summary of a normal reflection type mobile display. It is a cross-sectional schematic diagram which shows the layer structure outline | summary of the reflection type mobile display which made the retardation film in-cell. It is a line block diagram for demonstrating the alignment film formation method of this invention. It is structure explanatory drawing of an excimer UV lamp. It is explanatory drawing for demonstrating the relationship between the excimer UV irradiation amount to the alignment film for retardation films, and the contact angle of water. It is explanatory drawing for demonstrating the relationship between the excimer UV irradiation amount to the alignment film for retardation films, and the black luminance of a liquid crystal cell reflection part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... The polarizing plate 2 on the visual recognition side ... The retardation film 3 on the visual recognition side ... The color filter 3a ... The transparent substrate 3b on the visual recognition side ... The colored layer 4 ... The visual recognition side Transparent electrode 5 of the viewing side Liquid crystal alignment film 6 on the viewing side Reflecting mirror 7 Liquid crystal orientation film 8 on the facing side Visible transparent electrode 9 on the viewing side Face-to-face transparent substrate 10 ... Visually-facing face-side retardation film 11 ... Visually-facing face-side polarizing plate 12 ... Backlight 13 ... Retardation film alignment film 14 ... Anisotropy The phase difference film 15 of the isotropic phase difference film 16 ... the coating device 17 ... the oven 18 ... the rubbing device 19 ... the UV irradiation means 20 ... the substrate passing line 21 ... N ₂ gas supply slit 22 · · · UV irradiance monitor photodetector 23 · · · UV irradiance monitor photodetector of the light receiving unit 24 · · · UV anti Mirror 25 · · · UV lamp 26 · · · UV irradiation windows 27 · · · N ₂ gas supply port 28 · · · N ₂ gas outlet d, d / 2 ··· liquid crystal cell gap

Claims (10)

  A method for forming an alignment film for use in a liquid crystal display device, wherein the alignment film is irradiated with UV (ultraviolet rays) after being applied and baked and before rubbing.   The alignment film forming method according to claim 1, wherein the alignment film is an alignment film for a retardation film.   The alignment film forming method according to claim 1 or 2, wherein the ultraviolet ray to be irradiated is a UV irradiation method having a peak in a vacuum ultraviolet region having a wavelength of 100 to 200 nm.   4. The alignment film forming method according to claim 1, wherein the ultraviolet ray to be irradiated is an excimer UV irradiation method using Xe (xenon) gas having a peak at a single wavelength near 172 nm. . In excimer UV irradiation system using the Xe gas, the amount of ultraviolet rays irradiated alignment film forming method according to claim 4, characterized in that in the range of ^{10mJ / cm 2 ~200mJ / cm 2} .   6. The alignment film forming method according to claim 4, wherein in the excimer UV irradiation method using the Xe gas, the distance between the UV irradiation window surface and the surface of the substrate to be irradiated is in a range of 1 mm to 5 mm. .   A rubbing apparatus for use in forming a liquid crystal alignment film or a film having orientation by rubbing, and comprising means for irradiating UV (ultraviolet light) before rubbing treatment of the film.   8. The rubbing apparatus according to claim 7, wherein the irradiating ultraviolet rays are emitted from a UV irradiation means having a peak in a vacuum ultraviolet region having a wavelength of 100 to 200 nm.   The rubbing apparatus according to claim 7 or 8, wherein the ultraviolet rays to be emitted are emitted from an excimer UV irradiation means sealed with Xe (xenon) gas having a peak at a single wavelength near 172 nm.   The rubbing apparatus according to claim 9, wherein in the excimer UV irradiation means sealed with the Xe gas, the distance between the UV irradiation window surface and the irradiated substrate surface can be set in a range of 1 mm to 5 mm.