JP4846603B2 - Alignment film manufacturing method - Google Patents

Description

  The present invention relates to a technical field of a manufacturing method for manufacturing a liquid crystal display device.

2. Description of the Related Art Conventionally, for example, VA (Vertically Aligned) mode liquid crystal display devices in which liquid crystal molecules having negative dielectric anisotropy are sealed so as to be vertically aligned between a pair of substrates are widely known.
In the VA mode liquid crystal display device, liquid crystal molecules are aligned substantially perpendicular to the main surface of the substrate when no electric field is applied, and are inclined with respect to the main surface of the substrate when an electric field is applied.

At the time of vertical alignment, the light passes through the liquid crystal layer with almost no change in the plane of polarization, and at the time of tilt alignment, the plane of polarization of incident light rotates due to the birefringence.
It is said that if a polarizing plate is arranged so as to block light during vertical alignment, a higher contrast can be realized as compared with a TN mode liquid crystal display device.

  In order to make the change direction of the alignment of each liquid crystal molecule constant, the liquid crystal is arranged on the alignment film, and the liquid crystal molecules are aligned in advance with a small tilt angle (pretilt angle) by this alignment film.

  Conventionally, organic materials such as polyimide have been widely known for this alignment film. However, since alignment films made of organic materials are inferior in light resistance and heat resistance, in recent years, inorganic light distribution films made of inorganic materials such as SiO and excellent in light resistance and heat resistance have been developed. Conventionally, oblique deposition has been used to form the inorganic alignment film.

The oblique deposition is a method in which an inorganic material such as SiO ₂ , SiO, Al ₂ O ₂ is deposited by tilting the substrate so that the incident angle enters obliquely. The incident angle of vapor, the pressure during film formation (oxygen) The pretilt angle is controlled by gas introduction). (JP 2004-163921)
However, since the alignment film thus prepared has a low density, the barrier property is low, and when liquid crystal is arranged on the alignment film, ions contained in the liquid crystal permeate the alignment film, and the alignment film If it enters into the transparent conductive film located in the lower layer, display defects will occur.

Therefore, a method of forming a barrier layer having a high barrier property has been proposed by dividing the film formation process into two stages of vertical vapor deposition and oblique vapor deposition (Patent Publication 2005-77901). If it is transported between them, the processing time becomes long, and if vertical vapor deposition and oblique vapor deposition are performed in one film forming apparatus, there is a possibility that problems such as dust generation and leakage gas occur.
JP 2004-163921 A JP-A-2005-77901

  The present invention has been made to solve the above-described problems, and an object of the present invention is to form an alignment film capable of aligning liquid crystals at a desired pretilt angle and having high chemical stability.

Regarding the barrier property of the alignment film, the higher the film density of the alignment film, the higher the barrier property. The film density of the alignment film can be obtained indirectly by measuring the refractive index of the alignment film.
When the alignment film is formed by vapor deposition, in the range where the incident angle is 35-60 ° and in the pressure range of 6 × 10 ^{−3 to} 3 × 10 ⁻² Pa, the larger the incident angle, the higher the deposition pressure. The structure of the alignment film formed changes from a smooth one to a columnar shape, and irregularities necessary for tilting the liquid crystal are formed on the surface of the alignment film. As a result, the larger the incident angle, the higher the pressure. The higher the value, the larger the pretilt angle.

  In order to increase the incident angle, the substrate may be deposited by tilting and tilting it from the horizontal plane. To change the deposition pressure, the amount of oxygen introduced into the vacuum chamber is changed, and the oxygen pressure in the vacuum chamber is changed. Just change.

The inventors of the present invention measured the relationship between the deposition pressure, the refractive index, and the pretilt angle in order to form an alignment film that satisfies both the barrier property requirement and the pretilt angle requirement.
The relationship between the deposition pressure and the refractive index when the substrate is tilted 45 ° from the horizontal state, the evaporation material made of silicon dioxide is melted and evaporated in a vacuum atmosphere, and the alignment film made of the silicon dioxide film is formed on the substrate surface. It shows in following Table 1 and FIG. 3, and the relationship between the film-forming pressure and a pretilt angle is shown in Table 2 and FIG. The film formation rate was 5 mm / second and the film thickness was 1000 mm.

3 and 4, when the film formation pressure is different, the refractive index is larger as the film formation pressure is smaller, and conversely, the pretilt angle is larger as the film formation pressure is higher.
In addition, if the tilt angle of the substrate with respect to the horizontal plane is increased, the pretilt angle can be increased. However, if the alignment film is formed by vapor incident from an oblique direction, the film density is lowered and the barrier property is deteriorated.
Therefore, if the tilt angle and film formation pressure for obtaining a large pretilt angle are set, the barrier property cannot be obtained.

  Based on the fact that the film quality of the surface of the alignment film has an influence on the pretilt angle of the liquid crystal, the inventors have not affected the film quality of the lower layer of the alignment film. In order to obtain the pretilt angle, an inclination angle is set. First, after forming an alignment film at a pressure at which the barrier property is obtained at the inclination angle, the pressure is changed without changing the inclination angle. It has been found that an alignment film having a film quality capable of obtaining a pretilt angle may be formed, and the present invention has been created.

The present invention based on such knowledge is obtained by forming the alignment film of a liquid crystal display device in which an alignment film mainly composed of a transparent conductive film and silicon dioxide is formed on a substrate, and liquid crystal is disposed on the alignment film surface. In the manufacturing method for manufacturing, the step of forming the alignment film is performed by holding the substrate on which the transparent conductive film is formed in a vacuum atmosphere in a state where the substrate is inclined at a predetermined inclination angle with respect to a horizontal plane. Oxygen is introduced into the atmosphere, and a vapor deposition material mainly composed of silicon dioxide is melted in a state where the oxygen pressure in the vacuum atmosphere is set to a first film formation pressure, and vapor of the vapor deposition material is released, and After the bottom layer of the alignment film is grown on the film surface, the oxygen pressure in the vacuum atmosphere is set to a second film formation pressure higher than the first film formation pressure, and the surface layer of the alignment film is formed into the bottom surface. A method for producing an alignment film formed on a layer
The present invention is a method for manufacturing an alignment film, in which the bottom layer and the surface layer are grown in the same vacuum chamber.
The present invention is a method for producing an alignment film, wherein the tilt angle is the same during the formation of the bottom layer and during the formation of the surface layer.
The present invention is a method for manufacturing an alignment film, which is a method for manufacturing an alignment film in which nitrogen gas is introduced into the vacuum atmosphere.
The present invention is a method for producing an alignment film, wherein the film thickness of the surface layer is 10 nm or more.

Prepare a substrate on which a transparent conductive film (ITO film) with a thickness of 1000 mm is formed by sputtering, and tilt angles (angles between the substrate surface and a horizontal plane) 40 °, 45 °, 50 °, pressure 2 × 10 ^The alignment films were formed by combining the conditions of ⁻² Pa and 2 × 10 ⁻³ Pa. Each alignment film was measured for refractive index with an ellipsometer, liquid crystal (trade name “MLC6608” manufactured by Merck & Co., Inc.) was further disposed on each alignment film, and the pretilt angle was measured by a crystal rotation method.
Deposition conditions other than the tilt angle and pressure are shown in Table 3 below, and the measurement results are shown in Tables 4 and 5 below.

FIG. 5 is a graph showing the relationship between the inclination angle and the refractive index obtained from the above measurement results. When the curve indicated by L ₁ is formed at a pressure of 2 × 10 ⁻² Pa, the curve indicated by H ₁ is This is the case of forming at a pressure of 2 × 10 ⁻³ Pa.

FIG. 6 is a graph showing the relationship between the tilt angle and the pretilt angle obtained from the above measurement results. When the curve indicated by the symbol H ₂ is formed at a pressure of 2 × 10 ⁻² Pa, the curve indicated by the symbol L ₂ is This is the case of forming at a pressure of 2 × 10 ⁻³ Pa.
As can be seen from FIGS. 5 and 6, the refractive index decreases and the pretilt angle increases as the inclination angle of the substrate from the horizontal plane increases.

  In the present invention, when the pressure is reduced at the same inclination angle among the combinations of the pressure value and the inclination angle value at which a necessary pretilt angle is obtained, an inclination angle at which a necessary refractive index is obtained is obtained in advance. First, the bottom layer of the alignment film is formed by vapor deposition at a first film formation pressure that provides the necessary refractive index, and then the pressure is changed to a second film formation pressure that is higher than the first film formation pressure. Thus, a surface layer capable of obtaining a necessary pretilt angle is formed.

Since the alignment film formed according to the present invention has both barrier properties and alignment properties, it is not necessary to form the barrier film separately from the alignment film by using different film forming apparatuses.
Since the alignment film formed in the present invention contains SiO ₂ as a main component, the liquid crystal display device is superior in light resistance and heat resistance compared to the case where a resin film is used as the alignment film.

Reference numeral 5 in FIG. 1 shows an example of a film forming apparatus that can be used in the method of the present invention.
The film forming apparatus 5 has a vacuum chamber 51. A substrate holder 57 is disposed inside the vacuum chamber 51. A rotation shaft 55 is horizontally disposed inside the vacuum chamber 51, and the substrate holder 57 is attached to the rotation shaft 55. When the rotation shaft 55 rotates, the substrate holder 57 is inclined at a desired angle with respect to the horizontal plane. It is configured to be able to.
Reference numeral 11 in FIG. 1 denotes a substrate held by the substrate holder 57 and having the surface S inclined with respect to the horizontal plane H by an inclination angle θ (0 <θ <90 °).

A vapor deposition container 52 is disposed immediately below the substrate holder 57 inside the vacuum chamber 51. A vapor deposition material 54 is disposed inside the vapor deposition container 52.
A vacuum exhaust system 59 is connected to the vacuum chamber 51. When the inside of the vacuum chamber 51 is evacuated by the evacuation system 59 and the heater (not shown) is energized from the power source 4 to heat and melt the vapor deposition material 54 in the vapor deposition vessel 52, the vapor of the vapor deposition material 54 enters the vacuum chamber 51. The vapor of the vapor deposition material 54 reaches the surface of the substrate 11 as it is released.

  A gas supply system 58 is connected to the vacuum chamber 51. The gas supply system 58 is provided with a tank (not shown) so that the auxiliary gas accommodated in the tank can be introduced into the vacuum chamber 51 while controlling the flow rate.

  The vacuum chamber 51 is provided with a pressure sensor 67 and a film thickness sensor 63. The pressure sensor 67 is connected to the control device 2, and the film thickness sensor 63 is connected to the control device 2 via the film thickness meter 6, and the pressure sensor 67 measures the pressure inside the vacuum chamber 51, and the film thickness sensor The thickness of the thin film grown on the surface of the substrate 11 can be measured by 63.

The control device 2 controls the amount of auxiliary gas introduced from the gas introduction system 58 into the vacuum chamber 51 based on the measured values of the pressure sensor 67 and the film thickness sensor 63 as described below.
That is, the control device 2 is configured to store one or a plurality of pressure values, and when one pressure value is selected from the stored pressure values, the control device 2 is controlled by the pressure sensor 67. The gas introduction system 58 is controlled so that the measured pressure value in the vacuum chamber 51 is equal to the selected pressure. Here, as will be described later, the first film formation pressure and the second film formation pressure higher than that are stored.

  The control device 2 stores a film thickness reference value. When the measured value of the film thickness sensor 63 is smaller than the film thickness reference value, the first film forming pressure is selected and is equal to or greater than the film thickness reference value. Then, the second film formation pressure is selected.

Next, a process for forming an alignment film using the film forming apparatus 5 will be described.
The range of the pretilt angle required for the liquid crystal display device is known in advance, and as described above, the tilt angle θ that can obtain the necessary pretilt angle and refractive index when the film forming pressure is changed is obtained in advance. The deposition pressure at which a necessary refractive index is obtained and the deposition pressure at which a necessary pretilt angle is obtained when vapor deposition is performed at the tilt angle are defined as a first deposition pressure and a second deposition pressure, respectively. And stored in the control device 2.

Further, the thickness of the bottom layer of the alignment film to be formed is stored in the control device 2 as a reference film thickness.
A vapor deposition material 54 containing silicon dioxide as a main component is disposed in the vapor deposition vessel 52, oxygen gas is disposed as an auxiliary gas in the gas supply system 58, and the vacuum exhaust system 59 is operated to form a vacuum atmosphere in the vacuum chamber 51. To do.

  Reference numeral 10 in FIG. 1 indicates a laminated substrate which is a film formation target. The laminated substrate 10 has a substrate 11 and a transparent electrode film 12 disposed on the surface of the substrate 11, and the transparent electrode film 12 is exposed on the surface.

While maintaining the vacuum atmosphere in the vacuum chamber 51, the laminated substrate 10 is carried into the vacuum chamber 51, the surface where the transparent electrode film 12 is exposed (film formation surface) is directed to the vapor deposition container 52, and the horizontal substrate holder 57 is placed. After the holding, the substrate holder 57 is tilted, and the laminated substrate 10 is tilted so that the angle between the surface S of the substrate 11 and the horizontal plane H becomes a previously determined tilt angle θ.
A heater 61 is provided inside the vacuum chamber 51. The heater 61 is energized to heat the laminated substrate 10 to a predetermined temperature.

A shutter 68 is provided between the vapor deposition vessel 52 and the substrate holder 57, and the vapor deposition material 54 in the vapor deposition vessel 52 is heated with the shutter 68 closed to release vapor, and oxygen gas is introduced into the vacuum chamber 51. When the first film forming pressure is stabilized, the shutter 68 is opened, and the vapor of the vapor deposition material 54 reaches the film forming surface of the laminated substrate 10 while maintaining the laminated substrate 10 at a predetermined temperature. The bottom layer of is grown.
When the film thickness of the bottom layer reaches the reference film thickness, the shutter 68 is once closed, the oxygen introduction amount is increased, and the inside of the vacuum chamber 51 is changed from the first film formation pressure to the second film formation pressure.

When the pressure in the vacuum chamber 51 is stabilized at the second film-forming pressure, the shutter 68 is opened, and the surface layer of the alignment film is grown on the bottom layer. An alignment film having a surface layer from which corners can be obtained is formed.
When the surface layer reaches a predetermined film thickness, the shutter 68 is closed, the heating of the vapor deposition material 54 is stopped, and the vapor emission is stopped, and the laminated substrate 10 is carried out of the vacuum chamber 51.

  Next, a process of manufacturing the liquid crystal display device by assembling the laminated substrate 10 on which the alignment film is formed will be described. The two laminated substrates 10 and 20 having the alignment film formed on the film formation surface in the above-described steps are The surfaces on which the alignment films 15 and 25 are formed face each other, a spacer (not shown) is sandwiched between them, the laminated substrates 10 and 20 are bonded together with a sealing member 33, and the liquid crystal 31 is disposed between the laminated substrates 10 and 20. If the polarizing plates 17 and 27 are arranged on the surface of the substrates 11 and 21 opposite to the side on which the alignment films 15 and 25 are formed, the liquid crystal display device 1 as shown in FIG. 2 is obtained.

<Test 1>
With the film forming apparatus 5, the bottom layer is formed at 2 × 10 ⁻³ Pa (first film forming pressure) while maintaining the tilt angle at 42 °, and 2 × 10 ⁻² Pa (second formed film). When the surface layer is laminated on the surface of the bottom layer with a film pressure) to form an alignment film having a total thickness of 500 mm, the ratio of the thickness of the bottom layer to the thickness of the surface layer is 50/450, Six kinds of alignment films were formed on the film formation surfaces of the separate laminated substrates 10 in place of 100/400, 200/300, 300/200, 400/100, and 500/0.

A liquid crystal (trade name “MLC6608” manufactured by Merck & Co., Inc.) was placed on the surface of each alignment film, and the pretilt angle was measured by a crystal rotation method.
The alignment film was formed at a rate of 5 Å / second, the power applied to the heating means (heater) was 150 × 7 (mA, KV), and the distance between the vapor deposition vessel 52 and the substrate 11 was 1000 mm. Table 6 below shows the thickness of the surface layer and the value of the pretilt angle corresponding to the thickness of the surface layer, and the relationship between the thickness of the surface layer and the pretilt angle is shown in FIG. Show.

  From Table 6 and FIG. 7, when the film thickness of the surface layer is too thin, less than 100 mm (10 nm), the pretilt angle is small due to the influence of the bottom layer, even if the inclination angle θ and the film formation pressure are the same, If the surface layer was 10 nm, the same pretilt angle as when the film thickness was large was obtained.

<Test 2>
The apparent refractive index of the six types of alignment films formed in “Test 1” was measured, and the relationship between the film thickness of the surface layer and the refractive index was examined. The apparent refractive index is the refractive index of the entire alignment film including the surface layer and the bottom layer. FIG. 8 shows the relationship between the film thickness of the surface layer and the measured refractive index among the film thicknesses of the entire alignment film.
As the film thickness of the surface layer decreases and the film thickness of the bottom layer increases, the ratio of the layer having a higher refractive index increases, so that the refractive index of the entire alignment film increases as shown in FIG.

  From FIG. 8 and FIG. 7 above, for example, an alignment film having a surface layer thickness of 100 mm (10 nm) and a bottom layer thickness of 400 mm (40 nm) maintains a high refractive index (about 1.45). , Having a pretilt angle of about 3 °, the alignment film is excellent in both alignment and barrier properties.

<Test 3>
A laminated substrate 10 having a transparent electrode film 12 made of ITO formed on the surface is prepared. Under the same conditions as in “Test 1”, the film thickness of the surface layer and the film of the bottom layer are not changed without changing the film thickness of the entire alignment film. Alignment films having different thicknesses were formed on separate laminated substrates 10.

  Liquid crystal was arranged on each of the formed alignment films to produce five types of liquid crystal cells (liquid crystal display device 1), and a light resistance evaluation test of the liquid crystal cells was performed. The results of the evaluation test are shown in Table 7 below together with the film thickness of the bottom layer and the film thickness of the surface layer.

  In the liquid crystal cell in which the film thickness of the bottom layer is zero and the alignment film is composed only of the surface layer, the screen burn-in occurred in 800 hours, but the liquid crystal cell provided with the bottom layer of 100 mm (10 nm) or more on the alignment film Then, no burn-in occurred for 2000 hours or more.

  Burn-in occurs when ions derived from the transparent electrode films 12 and 22 enter the liquid crystal through the alignment film. Therefore, the transparent electrode films 12 and 22 are made of a transparent conductive material that emits ions such as ITO. It can also be seen that a liquid crystal display device capable of displaying images stably for a long time can be obtained if the thickness of the bottom layer is 10 nm or more.

As described above, the case where the pressure is changed in two stages when forming the alignment film has been described. However, the present invention is not limited to this, and at least the surface layer is formed at a high pressure. If at least a part of the film is formed at a pressure lower than that of the surface layer, the pressure may be changed in three or more steps. Further, the pressure may not be changed stepwise but may be continuously increased so that the pressure becomes high when the film is finally formed from the surface to a predetermined film thickness depth.
Further, while the pressure inside the vacuum chamber 51 is increased from the first film formation pressure to the second film formation pressure, the vapor of the vapor deposition material 54 may reach the substrate 11 and the growth of the alignment film may be continued. .

The method for melting the vapor deposition material 54 is not particularly limited. A method of heating the vapor deposition material 54 with an electron beam from an EB gun, a heater is attached to the vapor deposition vessel 52, the vapor deposition vessel 52 is heated with the heater, and heat conduction is performed. A method of heating the vapor deposition material 54 can be employed.
The substrate 11 can be a transparent substrate such as a glass substrate or a plastic substrate.

  The method for forming the transparent electrode film is not particularly limited, and the film can be formed by a generally used film forming method such as a sputtering method or a vapor deposition method. After forming the transparent conductive film, the alignment film may be formed after patterning as necessary, or the alignment film may be formed without patterning.

  When the transparent electrode film is formed by vapor deposition and patterning by wet etching or dry etching is not necessary after film formation, the vapor deposition material mainly composed of the transparent conductive material is evaporated inside the vacuum chamber 51. Then, after forming the transparent electrode film, the alignment film can be formed by evaporating the vapor deposition material containing the inorganic material as a main component in the same vacuum chamber 51. In this case, since the transparent electrode film and the alignment film can be continuously formed without being exposed to the air, the film quality of the transparent electrode film and the alignment film is improved.

  The transparent conductive material constituting the transparent electrode film is not particularly limited, and any one selected from the group consisting of ITO (indium tin oxide), ZnO (zinc oxide), tin oxide, and tin oxide cadmium. More than one type of transparent conductive material can be used. Even when any of ITO, ZnO, tin oxide and cadmium tin oxide is used for the transparent electrode film, the ions of the transparent conductive material enter the liquid crystal if the refractive index of the alignment film is low. By providing a bottom layer having a high refractive index in the alignment film, ions can be prevented from entering the liquid crystal.

  The arrangement of the polarizing plates 17 and 27 is not particularly limited. If the polarizing plates 17 and 27 are arranged so that the polarization directions are orthogonal to each other, light incident from one polarizing plate 17 side passes through the polarizing plate 27 in the on state. Light is emitted and absorbed by the polarizing plate 27 in the off state. Further, if the polarizing plates 17 and 27 are arranged so that the polarization directions are parallel to each other, light incident from one polarizing plate 17 side is absorbed by the polarizing plate 27 in the on state, and the polarizing plate 27 is turned off in the off state. Passes through and emits light.

  In the above, the case where the substrate 11 and 21 are held by the substrate holder 57 so as to be horizontal and then rotated so that the inclination angle θ becomes the set angle has been described, but the present invention is not limited to this, The substrate holder 57 may be previously tilted so that the tilt angle θ becomes the set tilt angle, and the substrates 11 and 21 may be held by the substrate holder 57.

  Further, when the second film forming pressure and the necessary pretilt angle are not changed and the inclination angle θ does not need to be changed, the substrate holder 57 is not attached with a rotating means such as the rotating shaft 55. May be fixed in an inclined state so that the inclination angle θ becomes the set angle, and the structure of the apparatus becomes simpler.

  In the case of the VA liquid crystal display device 1, it is said that a practical pretilt angle is 2 ° or more and 5 ° or less. If the pretilt angle is less than 2 °, the responsiveness when switching from the off state to the on state is poor. Conversely, if the pretilt angle exceeds 5 °, light polarization occurs even in the off state, and light leaks out. . Therefore, it is desirable to form the alignment film at an inclination angle in which the pretilt angle when the alignment film is formed at the second film formation pressure is in the range of 2 ° to 5 °.

  The tilt angle is determined by the relationship between the second film formation pressure and the pretilt angle, and is not particularly limited. However, if the tilt angle is less than 35 °, alignment characteristics can be obtained even if the second film formation pressure is increased. However, if the tilt angle exceeds 50 °, the film forming speed becomes extremely slow. Therefore, the tilt angle is preferably 35 ° or more and 50 ° or less.

If the tilt angle is in the range of 35 ° to 50 ° and the second film forming pressure is in the range of 5 × 10 ⁻³ Pa to 3 × 10 ⁻² Pa, the above-described practical pretilt angle range. In addition, if the first film formation pressure is 1 × 10 ⁻⁴ Pa or more and 3 × 10 ⁻³ Pa or less, practical barrier properties can be obtained.

The case where the auxiliary gas is composed of oxygen gas has been described above, but the present invention is not limited to this, and either or both of N ₂ and Ar are placed in the vacuum chamber 51 together with oxygen gas as the auxiliary gas. The first and second film formation pressures can be formed by introducing and controlling the amount of the auxiliary gas introduced.

If oxygen gas or oxygen gas and Ar are introduced into the vacuum chamber 51, an alignment film mainly composed of SiO ₂ is obtained. If oxygen gas and N ₂ or oxygen gas and N ₂ and Ar are introduced, SiO ₂ is obtained. _An alignment film containing both ₂ and SiON is obtained.

Sectional drawing for demonstrating the film-forming apparatus used for film-forming of alignment film Sectional drawing for demonstrating an example of the liquid crystal display device of this invention Graph showing the relationship between deposition pressure and refractive index Graph showing the relationship between deposition pressure and pretilt angle Graph showing the relationship between tilt angle and refractive index Graph showing the relationship between tilt angle and pretilt angle Graph showing the relationship between the thickness of the surface layer and the pretilt angle Graph showing the relationship between the film thickness of the surface layer and the refractive index

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device 5 ... Film-forming apparatus 11, 21 ... Substrate 12, 22 ... Transparent electrode film 15, 25 ... Orientation film 31 ... Liquid crystal 51 ... Vacuum chamber 54 ... Vapor deposition material

Claims (5)

A manufacturing method for manufacturing the alignment film of a liquid crystal display device in which an alignment film mainly composed of a transparent conductive film and silicon dioxide is formed on a substrate, and a liquid crystal is disposed on the surface of the alignment film,
The step of forming the alignment film includes:
Holding the substrate on which the transparent conductive film is formed in a vacuum atmosphere in a state inclined at a predetermined inclination angle with respect to a horizontal plane;
Introducing oxygen into the vacuum atmosphere, melting a vapor deposition material mainly composed of silicon dioxide in a state where the oxygen pressure of the vacuum atmosphere is a first film formation pressure, releasing vapor of the vapor deposition material, After growing the bottom layer of the alignment film on the transparent conductive film surface,
A method for producing an alignment film, wherein the oxygen pressure in the vacuum atmosphere is set to a second film formation pressure higher than the first film formation pressure, and a surface layer of the alignment film is formed on the bottom layer.   The method for producing an alignment film according to claim 1, wherein the bottom layer and the surface layer are grown in the same vacuum chamber.   The method for producing an alignment film according to claim 2, wherein the inclination angle is the same during the formation of the bottom layer and during the formation of the surface layer.   The method for producing an alignment film according to claim 1, wherein nitrogen gas is introduced into the vacuum atmosphere.   The method for producing an alignment film according to claim 1, wherein the thickness of the surface layer is 10 nm or more.

Images