JP2010020111A - Liquid crystal apparatus and method of producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal apparatus excellent in display quality, in which the splay-bend alignment transistion is facilitated, the bend alignment maintenance after transition is facilitated, and the high retardation of a display region can be maintained. <P>SOLUTION: This liquid crystal apparatus includes a liquid crystal layer formed of nematic liquid crystal having positive dielectric anisotropy and a pair of substrates, which are opposite to each other with the liquid crystal layer held between them, at least one substrate being adapted to transmit light, wherein a display area part with a plurality of pixel electrodes disposed thereon and a non-display area part other than the display area part are arranged on one of the paired substrates, a counter electrode formed of a transparent electrode is disposed on the other substrate, inorganic alignment films are provided on the paired substrates at the liquid crystal layer side, and the inorganic alignment film disposed on at least the one substrate has a plurality of regions different in layer thickness of the inorganic alignment film. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a liquid crystal device and a manufacturing method thereof, and more particularly, to a liquid crystal device using an OCB (Optically Compensated Bend) mode capable of realizing a high-speed response and a manufacturing method thereof.

  Various liquid crystal alignment modes are used for liquid crystal elements depending on the application. For example, a TN (Twisted Nematic) mode, a VA (Vertical Aligned) mode, an IPS (In Plane Switching) mode, an OCB (Optically Compensated Bend) mode, and the like are well known. These liquid crystal alignment modes can be determined by the physical properties of the liquid crystal composition and the characteristics of the alignment film.

  In recent years, liquid crystal devices having high-speed response for displaying moving images have been actively developed, and among the liquid crystal alignment modes, the OCB mode has a relatively high-speed response and is attracting attention. .

  In the OCB mode, a liquid crystal alignment state called bend alignment is used for display operation, but alignment transition from the splay alignment of the initial alignment state is necessary for forming the bend alignment. A transition voltage higher than a certain voltage is required for this orientation transition. Since the driving voltage of the liquid crystal element increases when the transition voltage increases, it is preferably as low as possible.

It is known that increasing the pretilt angle of the liquid crystal layer, reducing the elastic constant (K ₃₃ / K ₁₁ ) of the liquid crystal composition, and the like are effective for reducing the transition voltage. In particular, by setting the pretilt angle to 40 ° or more, a transition voltage is not required, and it is possible to form a bend alignment without going through a splay alignment state.

However, if the pretilt angle is set high, bend transition is likely to occur, but the retardation of the liquid crystal layer is lowered, and as a result, there is a problem that light utilization efficiency is lowered.
In order to solve this problem, reports have been made to facilitate bend alignment transition even at a low pretilt angle.

  For example, in patent document 1, the area | region which expresses several pretilt angles is formed in the board | substrate surface. Specifically, the low pretilt angle region is enclosed by the high pretilt angle region, thereby improving the ease of occurrence of the spray-bend transition.

Further, Patent Document 2 describes a method of forming a transition nucleus of a spray-bend transition by changing the electric field direction around the notch by providing a notch in the pixel electrode.
JP 2007-017502 A JP 2006-251605 A

  However, the method of Patent Document 1 is not a structure sufficient to lower the bend transition voltage of the liquid crystal layer, and further reduction of the bend transition voltage and stabilization of the bend alignment are desired. Furthermore, there is a problem that an inorganic alignment film is laminated in the display region and the pretilt angle is lowered as compared with the peripheral region, and as a result, the voltage actually applied to the liquid crystal layer is reduced.

Further, the method of Patent Document 2 has a problem that the reflectance decreases because the area of the pixel electrode decreases.
The present invention has been made in view of the above-described problems, and is capable of easily changing the spray-bend alignment, maintaining the bend alignment after the transfer, and maintaining a high retardation in the display area. A liquid crystal device and a manufacturing method thereof are provided.

  A liquid crystal device that solves the above-described problem is a liquid crystal device that controls retardation of a liquid crystal layer by a voltage applied to the liquid crystal layer, the liquid crystal layer including a nematic liquid crystal having positive dielectric anisotropy, and the liquid crystal layer. A pair of substrates that are opposed to each other and at least one substrate transmits light, a display region portion in which a plurality of pixel electrodes are disposed on one of the pair of substrates, and the display region A non-display area portion that is an area other than the above is disposed, a counter electrode made of a transparent electrode is disposed on the other substrate, and the liquid crystal layer side of the pair of substrates is an inorganic alignment mainly composed of an inorganic material. The inorganic alignment film provided on the at least one substrate has a plurality of regions having different thicknesses of the inorganic alignment film.

  A method of manufacturing a liquid crystal device that solves the above-described problem is a method of manufacturing a liquid crystal device that controls retardation of a liquid crystal layer by a voltage applied to the liquid crystal layer, and forms a first inorganic alignment film on a pair of substrates. And a step of forming a second inorganic alignment film in which a film formation region is limited on at least one substrate on which the inorganic alignment film is formed.

  According to the liquid crystal device of the present invention, by setting the thickness of the inorganic alignment film in the display region to be thin, the pretilt angle is lowered, the splay-bend transition in the display region is facilitated, and the bend alignment stability is improved. Can be made. Further, since the thickness of the alignment film in the display region can be reduced, it is possible to prevent a decrease in effective voltage to the liquid crystal layer. Since the retardation of a display area can be maintained high from this, the improvement of display quality can be achieved.

  In addition, the present invention provides a method for manufacturing a liquid crystal device with excellent display quality, in which the splay-bend alignment transition is easy, the bend alignment is easily maintained after the transition, and the retardation of the display region can be maintained high. it can.

Hereinafter, the present invention will be described in detail.
As a result of intensive studies, the present inventors have found out conditions for producing an inorganic alignment film for expressing a pretilt angle of 40 ° or more when an inorganic alignment film is used, and film formation at the same deposition angle in the process. However, it has been found that there is a correlation between the film thickness of the inorganic alignment film and the pretilt angle above a certain deposition angle. Based on this fact, the present invention was completed.

  A liquid crystal device according to the present invention is a liquid crystal device that controls retardation of a liquid crystal layer by a voltage applied to the liquid crystal layer, the liquid crystal layer mainly comprising a nematic liquid crystal having positive dielectric anisotropy, and the liquid crystal layer A pair of substrates that are opposed to each other with at least one substrate transmitting light, a display region portion in which a plurality of pixel electrodes are disposed on one of the pair of substrates, and the display A non-display area portion which is an area other than the area is disposed, a counter electrode made of a transparent electrode is disposed on the other substrate, and an inorganic material mainly composed of an inorganic material is disposed on the liquid crystal layer side of the pair of substrates. The inorganic alignment film having an alignment film and disposed on the at least one substrate has a plurality of regions having different thicknesses of the inorganic alignment film.

The alignment state during the display operation of the liquid crystal layer is preferably bend alignment.
Of the plurality of regions having different thicknesses of the inorganic alignment film, the thickness of the inorganic alignment film in the display region is preferably smaller than the thickness of the inorganic alignment film in the non-display region.

In the liquid crystal layer on the non-display region, it is preferable that the alignment state of the liquid crystal layer in a state where no voltage is applied is bend alignment.
It is preferable that an electrode that does not contribute to display is disposed in the non-display area portion.

It is preferable that the shape of the display area is a rectangle, and electrodes that do not contribute to display arranged in the non-display area portion are formed along each side of the display area.
It is preferable that the inclination direction of the azimuth angle direction of the oxide columnar structure constituting the inorganic alignment film is the same direction in a plurality of regions having different film thicknesses.

  The method for manufacturing a liquid crystal device according to the present invention is a method for manufacturing a liquid crystal device in which the retardation of the liquid crystal layer is controlled by a voltage applied to the liquid crystal layer, and the step of forming a first inorganic alignment film on a pair of substrates And a step of forming a second inorganic alignment film with a limited film formation region on at least one substrate on which the inorganic alignment film is formed.

The step of forming the second inorganic alignment film in which the film formation region is limited is preferably a step of forming the second inorganic alignment film only in the non-display region.
The method of forming the first and second inorganic alignment films is preferably an oblique deposition method.

The method for limiting the film formation region is preferably a method in which a mask having an opening is placed on the substrate on which the first inorganic alignment film is formed.
It is preferable that the mask blocks at least the display area.

Next, an embodiment of the liquid crystal device of the present invention will be described.
FIG. 1 is a schematic view showing the configuration of an example of the liquid crystal device of the present invention. Reference numeral 101 denotes a pixel electrode, 102 denotes a transfer electrode, 103 denotes a seal portion, 104 denotes a sealing portion, 105 denotes an extraction electrode, and 106 denotes a display area. In FIG. 1, a display area 106 indicates an inner area surrounded by a dotted line. The non-display area 107 indicates a portion outside the display area outside the display area 106.

  The pixel electrode 101 is a transparent electrode such as ITO (Indium-Tin-Oxide) in the case of a transmission type, and a metal material that reflects incident light in the case of a reflection type, such as aluminum (Al) or silver (Ag). Etc. The counter electrode 202 shown in FIGS. 2 and 3 exists on the opposite side of the liquid crystal layer of these pixel electrodes, and the liquid crystal molecules are driven by a potential difference applied between the pixel electrode 101 and the counter electrode 202.

  In the present invention, it is preferable to install the transition electrode 102. The transition electrode 102 does not contribute to display, and is used for the purpose of assisting the change in the alignment state of the liquid crystal, particularly the liquid crystal alignment state on the pixel electrode. For example, the liquid crystal alignment state is changed from the splay alignment shown in FIG. 2 to the bend alignment shown in FIG. 3, and the splay-bend alignment transition in the subsequent pixel region is promptly generated. The transfer electrode 102 only needs to be disposed outside the pixel electrode. However, in order to promptly change the orientation on the pixel electrode, it is particularly preferable that the transfer electrode 102 be disposed along the outer periphery of the pixel electrode.

However, the transition electrode 102 is not particularly required if a change in liquid crystal alignment on the pixel electrode, for example, a splay-bend alignment transition occurs rapidly.
The display area 106 is an area including at least the pixel electrode 101, as long as it includes the pixel electrode 101, and may include the transfer electrode 102.

  The present invention is characterized in that the thickness of the inorganic alignment film is different between the display region 106 and the other non-display region 107, and in particular, since different liquid crystal alignment states are generated due to the difference in film thickness, The boundary of the non-display area must be set appropriately.

  When the transition electrode 102 is provided, if the boundary between the display area 106 and the non-display area 107 is provided along the transition electrode 102, the splay-bend transition that occurs in the transition electrode 102 is promptly applied to the pixel electrode 101. This is a desirable configuration for migration. This state is as shown in the schematic diagram showing the boundary between the first inorganic alignment film and the second inorganic alignment film in the liquid crystal device of the present invention in FIG.

  A material used for a general liquid crystal device is applied to the seal portion 103 and the sealing portion 104, and an extreme adverse effect on the liquid crystal material enclosing region (not shown) surrounded by the seal portion 103 and the sealing portion 104, for example, liquid crystal alignment. The material is not particularly limited as long as it does not cause disturbance, durability, or extreme deterioration in weather resistance.

  Spacers-beads (not shown) for determining the cell thickness of the liquid crystal device, that is, the distance between the upper substrate 201 and the lower substrate 206 shown in FIG. This can also be selected depending on the desired cell thickness.

  The extraction electrode 105 is an active matrix circuit such as a TFT (Thin-Film-Transistor) circuit (not shown) or a MOS (Metal-Oxide-Semiconductor) transistor circuit (not shown) connected to the pixel electrode 101, or a transfer electrode 102. In order to supply a driving voltage to the counter electrode 202, the liquid crystal device is used to connect a device such as an external driver.

  FIG. 2 is a schematic view showing an alignment state (splay alignment state) when no initial voltage is applied to the display region in the liquid crystal device of the present invention. That is, FIG. 2 is a part of a cross section of the display region 106 in the liquid crystal device shown in FIG. 201 is an upper substrate, 202 is a counter electrode, 203 is a first inorganic alignment film, 204 is a liquid crystal layer A, 205 is a pixel electrode, and 206 is a lower substrate.

  Since the upper substrate 201 needs to transmit light, a light-transmitting material such as glass is used. Similarly, since the counter electrode 202 is also required to have optical transparency, it is necessary to use a transparent electrode such as ITO.

  In the case of a transmissive liquid crystal device, the lower substrate 206 is made of a light transmissive material, and an active matrix circuit for driving the pixel electrode 205 is formed thereon. In that case, the pixel electrode 205 becomes a transparent electrode. In the case of the reflective type, the pixel electrode 205 is a reflective electrode that reflects incident light as described above.

The first inorganic alignment film 203 has a function of aligning a liquid crystal layer disposed between the upper substrate 201 and the lower substrate 205 in a certain direction.
In the present invention, an alignment film of an inorganic material is used. The materials of the first inorganic alignment film and the second inorganic alignment film may be the same or different.

As the inorganic material, any material having a desired liquid crystal alignment ability may be used. For example, an oxide such as silicon oxide (SiOx: x) such as silicon dioxide (SiOx) or silicon monoxide (SiO) is used. = 1 to 2), magnesium oxide (MgO), aluminum oxide _{(Al 2 O} 3), zinc oxide (ZnO), titanium oxide _(TiO 2), zirconium oxide _(ZrO 2), chromium oxide _{(Cr 2 O} 3) , Cobalt oxide (Co ₃ O ₄ ), iron oxide (Fe ₂ O ₃ , Fe ₃ O ₄ ) and the like, fluorides such as magnesium fluoride (MgF ₂ ), and nitrides such as silicon nitride (SiNx) and nitride Aluminum (AlN) etc. are mentioned.

However, it is preferable to use silicon oxide (SiOx) such as silicon dioxide (SiO ₂ ) and silicon monoxide (SiO) in order to sufficiently exhibit the effects of the present invention. This is because the liquid crystal alignment state of these materials can be controlled relatively freely depending on the formation conditions.

  The first inorganic alignment film 203 may be produced by any method. Examples thereof include PVD (Physical Vapor Deposition) methods such as vapor deposition and sputtering, CVD (Chemical Vapor Deposition) methods, and wet processes such as sol-gel methods.

  Among these, when a method generally called oblique deposition is used, a structure in which a plurality of fine columnar structures are grown with an inclination with respect to the substrate normal can be obtained. The use of such a structure makes it easy to control the alignment of liquid crystal molecules, so that the oblique deposition method is a particularly preferable manufacturing method.

  Next, the oblique deposition method will be described. FIG. 6 is a schematic view of the oblique deposition method in the method for manufacturing a liquid crystal device of the present invention. FIG. 5 is a schematic view showing a pretilt angle in the liquid crystal device of the present invention. The oblique deposition method is performed using an apparatus as shown in FIG. By appropriately setting the deposition angle 605 in the oblique deposition method, the pretilt angle 501 of the liquid crystal shown in FIG. 5 can be controlled.

  In the present invention, the first inorganic alignment film 203 is in the vicinity of the upper and lower inorganic alignment films above and below the liquid crystal layer A204 shown in FIG. The liquid crystal molecules are placed on the upper and lower substrates so that the liquid crystal molecules are inclined in the same direction. By arranging an inorganic alignment film so that the alignment processing directions of the upper substrate and the lower substrate are parallel, and forming the first inorganic alignment film 203 so as to have an appropriate pretilt angle, the liquid crystal alignment of the liquid crystal layer A204 is achieved. The state can be a splay alignment state as shown in FIG.

  The liquid crystal layer A204 needs to form a splay alignment as described above and a bend alignment as shown in FIG. 3 at the time of display. However, once the bend alignment is formed, it is not necessary to form the splay alignment again, and it is preferable if the bend alignment state can be maintained.

  The liquid crystal material used in the liquid crystal layer of the present invention is a nematic liquid crystal, has positive dielectric anisotropy, forms a bend alignment at the time of display, and can control the liquid crystal alignment state such as the pretilt angle by the alignment film. I just need it.

  FIG. 3 is a schematic view showing the alignment state (bend alignment state) in the non-display region of the liquid crystal device of the present invention. FIG. 3 shows a part of a cross section of a non-display region in the liquid crystal device shown in FIG. Here, 301 is a second inorganic alignment film, and 302 is a liquid crystal layer B.

  The liquid crystal layer B302 is the same liquid crystal material as the liquid crystal layer A204. However, the alignment state differs from that of the liquid crystal layer A 204 due to the influence of the second inorganic alignment film 301. In particular, a bend alignment state as exemplified in FIG. 3 is preferable. Forming a bend alignment without applying a voltage can be realized by appropriately selecting a physical property value such as an elastic constant of the liquid crystal material and the second inorganic alignment film 301. Specifically, the above state can be realized by providing the second inorganic alignment film 301 such that the pretilt angle 501 of the liquid crystal molecules shown in FIG.

  Similar to the first inorganic alignment film 203, the second inorganic alignment film 301 is installed so that the alignment treatment direction of the upper substrate and the alignment treatment direction of the lower substrate are parallel to each other. Further, it may be formed on the first inorganic alignment film 203 or directly on the lower substrate 206. From the viewpoint of the manufacturing process, it is better to form on the first inorganic alignment film 203. Since the process is simple, a configuration as shown in FIG. 3 is preferable.

  The thickness of the first inorganic alignment film used in the present invention is 10 nm to 200 nm, preferably 10 nm to 150 nm. The thickness of the second inorganic alignment film is 50 nm or more, preferably 100 nm or more.

  The inorganic alignment film used in the present invention is basically required to be able to change the desired alignment, that is, the liquid crystal alignment state of the display region and the non-display region. However, in order to improve the simplicity of the alignment film manufacturing process, the liquid crystal alignment state and the pretilt are prepared by using the oblique deposition method and by making the alignment film thickness of the display area and the non-display area different. It is preferable to control the angle.

When preparing the inorganic alignment film by the oblique vapor deposition method, the present inventors have changed the film thickness without changing the vapor deposition angle of the oblique vapor deposition film and the pretilt angle is changed. I found a phenomenon that changed greatly. FIG. 9 is a graph showing the relationship between the thickness of the inorganic alignment film and the pretilt angle at each deposition angle. In FIG. 9, SiO ₂ (silicon dioxide) produced by the oblique vapor deposition method was used for the inorganic alignment film. When the deposition angles are 85 ° and 87.5 °, it can be confirmed that the pretilt angle increases as the film thickness increases.

  Therefore, when the first inorganic alignment film 203 and the second inorganic alignment film 301 have the same conditions such as the vapor deposition angle, and change the pretilt angle by changing only the film thickness, the result is splay alignment and bend. It is possible to create different orientations on the same substrate surface.

  In FIG. 4, the second inorganic alignment film 301 is formed on both the upper and lower substrates. However, the region where only the first inorganic alignment film 203 is formed needs to be on at least one of the substrates. For example, if only the first inorganic alignment film 201 is formed in the display area 106 on the lower substrate 206 and the second inorganic alignment film 203 is formed in the other non-display areas, The second inorganic alignment film 301 may be formed over the entire surface. Further, the second inorganic alignment film 301 may not be formed in a region of the lower substrate 206 facing the display region 106 where only the first inorganic alignment film 201 is formed. That is, it is only necessary to form a region where only the first inorganic alignment film 201 is formed in a region corresponding to the display region 106 of either one of the substrates.

  In the above description, an example using the first inorganic alignment film and the second inorganic alignment film has been shown. However, as long as the same effect can be obtained, the number of inorganic alignment films is not limited to two. A film may be used.

Next, an example of an embodiment of a method for manufacturing a liquid crystal device will be described.
The manufacturing method of the liquid crystal device of the present invention includes the following steps.
(A) Process: Substrate preparation process (b) Process: Process for forming the first inorganic alignment film (c) Process: Process for forming the second inorganic alignment film (d) Process: Sealing agent application process (e) Step: liquid crystal injection / liquid crystal cell sealing step (f) step: liquid crystal alignment treatment step (g) step: wiring connection step

  Among these processes, the processes that are the features of the present invention are the processes (b) and (c), and the other processes are processes common to the manufacturing methods of other liquid crystal devices. Therefore, in the present invention, the steps (b) and (c) will be described in detail.

Step (b): Step of forming the first inorganic alignment film The first inorganic alignment film 203 may be formed by any method as long as a desired pretilt angle can be expressed. Preferably, the pretilt angle can be controlled over a wider range and can be easily formed by the oblique vapor deposition method shown in FIG.

  In the present invention, when the pretilt angle is controlled by controlling the thickness of the oblique vapor deposition film, it is necessary to form the inorganic alignment film by the oblique vapor deposition method. By forming the inorganic alignment film by the oblique deposition method, a high pretilt angle of about 30 ° to 50 °, which is a preferable pretilt angle range in the present invention, is set by appropriately setting the deposition angle and the thickness of the oblique deposition film. It can be expressed easily.

  The deposition angle 605 is basically not limited, but is preferably set to 70 ° or more, more preferably 80 ° or more. By producing the inorganic alignment film in such a range of the deposition angle, the liquid crystal alignment is stable and a relatively high pretilt angle can be formed.

(C) Process: The process of forming a 2nd inorganic alignment film The 2nd inorganic alignment film 301 is not formed in the display area 106 shown in FIG. To form. The selective formation method is not particularly limited, but it is preferable to perform selective formation by, for example, oblique vapor deposition using a mask because it is a relatively simple method.

Hereinafter, the present embodiment will be described in more detail using examples, but the present invention is not limited to those described in the examples.
Example 1
In this example, an oblique deposition film made of silicon oxide (SiOx) having a deposition angle of 85 ° and a film thickness of 40 nm (400 mm) is used as the first inorganic alignment film, and the deposition angle is used as the second inorganic alignment film. This is an example of manufacturing a liquid crystal device by selecting an obliquely deposited film having a thickness of 87.5 ° and a film thickness of 240 nm (2400 mm).

  In this embodiment, a liquid crystal driving Si substrate and a counter electrode substrate in which an ITO thin film serving as a counter electrode is formed on a glass substrate are used as the pair of substrates. A liquid crystal driving Si substrate includes a plurality of pixel electrodes formed in a display region for image display, and an alignment transition electrode formed for the purpose of applying a bend transition voltage to a liquid crystal layer formed outside the display region. In addition, a plurality of MOS transistor circuits for driving the liquid crystal on the pixel electrode in an active matrix and applying a bend transition voltage to the alignment transition electrode are formed.

  Next, a first inorganic alignment film is formed. The liquid crystal driving Si substrate and the counter electrode substrate are placed in a predetermined direction on the substrate holder in the oblique vapor deposition apparatus, the substrate holder is inclined so that the vapor deposition angle is 85 °, and the inorganic alignment film is formed by the oblique vapor deposition method. Is formed to a film thickness of 40 nm (400 mm).

  Next, a mask necessary for forming the second inorganic alignment film is placed on each substrate. The mask is not placed in close contact with the substrate surface, but is slightly lifted from the substrate surface. Therefore, a spacer having a thickness of about 100 μm is formed on the outer edge of the mask. Further, a mask having a shape covering the display area on the liquid crystal driving Si substrate is used. Further, a region of the counter electrode substrate that directly faces the display region on the liquid crystal driving Si substrate is also covered with a mask when the substrates are bonded together.

  In the above state, a second inorganic alignment film is formed. The azimuth direction of vapor deposition is the same direction as the first inorganic alignment film, the vapor deposition angle is set to 87.5 °, and oblique vapor deposition is performed so that the thickness of the second inorganic alignment film is 240 nm (2400 mm). Do.

  Here, a liquid crystal cell for measuring a pretilt angle is produced using the substrate on which the first inorganic alignment film is formed and the substrate on which the second inorganic alignment film is formed, and the pretilt on each inorganic alignment film is produced. Measure the corner. As the liquid crystal, a liquid crystal composition MLC-2050 (manufactured by Merck) was used. As a result, the pretilt angle on the first inorganic alignment film is 35.0 °, and the pretilt angle on the second inorganic alignment film is 48.1 °.

  Moreover, as a result of observing the fine structure of the inorganic alignment film using a scanning electron microscope (SEM), it can be confirmed that the growth directions of the SiOx columns of the first inorganic alignment film and the second inorganic alignment film are the same. .

  Next, a liquid crystal cell for forming a bend alignment is produced. A UV curable sealant is applied in a predetermined pattern shape on the liquid crystal driving Si substrate after the second inorganic alignment film is formed. Spacer beads having a diameter of 3 μm are mixed in the sealant.

  Next, a counter electrode substrate is placed in a predetermined direction and position on a liquid crystal driving Si substrate coated with a UV curable sealant. At the time of installation, the areas where the second inorganic alignment film on both substrates is not formed are overlapped.

  Next, UV irradiation and substrate heating are performed under predetermined conditions to produce an empty cell. Thereafter, a liquid crystal material MLC-2050 is injected into the empty cell using a liquid crystal injection device. Thereafter, the LC cell is sealed using a UV curable sealant.

Next, a flexible cable is connected to the extraction electrode formed on the liquid crystal driving Si substrate via an anisotropic conductive adhesive film (ACF).
Next, realignment treatment of the liquid crystal layer is performed. The LC cell is heated above the nematic-isotropic phase transition temperature (89 ° C.) of the liquid crystal, and then slowly cooled.

  Here, in order to confirm the alignment state of the liquid crystal, an alignment confirmation liquid crystal cell produced by the same method as the above production method is prepared except that the counter electrode substrate is used instead of the liquid crystal driving Si substrate. When this liquid crystal cell is introduced between two polarizing plates having a crossed Nicols arrangement and observed, the region where only the first inorganic alignment film is formed is in a brightly colored state, and the second inorganic alignment film In the region where is formed, the color was black. From this, it can be confirmed that in the region where only the first inorganic alignment film is formed, the liquid crystal layer forms splay alignment, and in the region where the second inorganic alignment film is formed, bend alignment is formed. .

  A voltage is applied to the alignment confirmation liquid crystal cell to shift the splay alignment region to bend alignment. First, when a rectangular wave voltage with a frequency of 60 Hz is gradually applied to the transition electrode arranged around the display area and the pixel electrode in the display area, the transition to the bend orientation starts at an applied voltage of 1.3 V or more, and 1.5 V is applied. In a few seconds, the entire region becomes bend alignment.

Thereafter, the voltage application was terminated, the sample was left in a state where no voltage was applied, and the change in the alignment state was observed, but no reverse transition to the splay alignment was observed.
From the above results, the influence of the bend alignment region formed on the second inorganic alignment film formed around the first inorganic alignment film, although the splay alignment state is normally stable Thus, it can be confirmed that the bend alignment is maintained.

  Next, a uniaxial phase compensation plate (+ A plate) is attached onto the glass substrate of the liquid crystal cell. A phase compensation plate having a retardation of 50 nm is installed so that the fast axis is orthogonal to the fast axis of the liquid crystal cell.

  When the liquid crystal cell is driven in this state and the voltage-reflectance characteristic (VR characteristic) is measured by irradiating the liquid crystal cell with light having a central wavelength of 550 nm in the optical system arrangement shown in FIG. 8, the voltage shown in FIG. -A reflectance characteristic curve can be obtained.

  The change in the voltage-reflectance characteristic shown in FIG. 10 is due to the fact that the retardation (phase difference) of the liquid crystal layer changes with the applied voltage. In the liquid crystal device of this embodiment, the amount of retardation is large when the applied voltage is low, the retardation amount decreases as the applied voltage is increased, and the reflectance also decreases as the retardation amount decreases.

Comparative Example 1
As a comparative example of Example 1, a liquid crystal cell manufactured by the same manufacturing method as Example 1 is evaluated except that only the first inorganic alignment film is used as the liquid crystal alignment film.
When the pretilt angle is measured, it is 35.0 ° as in the first embodiment.

  Next, when the alignment state was confirmed in the alignment evaluation liquid crystal cell, it was confirmed that the entire surface was splay alignment. In addition, after forming a bend alignment by applying a voltage higher than the transition voltage, when the voltage application is terminated and left standing, a phenomenon of reverse transition to the splay alignment after a few seconds is observed.

  From this, it can be confirmed that in the case of this comparative example, the bend alignment cannot be maintained in the state where no voltage is applied.

Comparative Example 2
As in Comparative Example 1, a liquid crystal cell produced by the same production method as Example 1 is evaluated except that only the second inorganic alignment film is used as the liquid crystal alignment film.

When the pretilt angle is measured, it is 48.1 ° as in the case of the first embodiment.
Next, when the alignment state is confirmed with a liquid crystal cell for alignment evaluation, it can be confirmed that the entire surface is in a bend alignment with no voltage applied.

  When the voltage-reflectance characteristic was measured using the liquid crystal cell having the above-described alignment state, a graph of the voltage-reflectance characteristic having a decrease in reflectance on the low voltage side as compared with the case of Example 1 was obtained. .

  Therefore, in the liquid crystal cell having the configuration of Comparative Example 2, it is possible to form a bend alignment without applying a voltage, but the reflectance decreases.

Example 2
Next, an example using an obliquely deposited film produced by ion beam assisted deposition as the first inorganic oriented film and an inorganic oriented film produced by performing ordinary obliquely deposited as the second inorganic oriented film Indicates.

  The first inorganic alignment film is produced by oblique deposition using an end-hole type ion source while irradiating Ar ions. The production conditions are a deposition angle of 85 °, an ion beam irradiation angle of 50 °, a cathode voltage of the ion source of 100 V, and a cathode current of 5 A. When the first inorganic alignment film is produced under these conditions, the pretilt angle is 32.1 °.

On the first inorganic alignment film, an inorganic alignment film having a vapor deposition angle of 87.5 ° and a film thickness of 2400 mm is produced using the same mask as in Example 1.
When the liquid crystal cell was fabricated and evaluated in this state, the same alignment state as in Example 1 was obtained, and the bend alignment was maintained after the voltage was applied to the display region and the bend transition occurred. Is observed.

  Moreover, when the VR characteristic was measured, the VR characteristic similar to Example 1 shown in FIG. 10 is obtained.

Example 3
In this example, a liquid crystal cell is produced by the same method as in Example 1 except that the first inorganic alignment film is not formed on the counter electrode substrate.

  The conditions for forming the first inorganic alignment are the same as in Example 1, with a vapor deposition angle of 85 ° and a film thickness of 40 nm (400 mm), and the conditions for forming the second inorganic alignment film are with a vapor deposition angle of 87.5 ° and 240 nm ( 2400cm).

  When the alignment confirmation cell was prepared, only the portion where the second inorganic alignment film was not formed was splayed in the same manner as in Example 1, and the other portions were bend aligned. Further, reverse transition after bend transition does not occur as in the first embodiment.

  As shown in FIG. 10, the VR characteristics are almost the same as those in Examples 1 and 2.

  INDUSTRIAL APPLICABILITY The present invention can be used for a liquid crystal display element using an inorganic alignment film formed by a film formation method such as oblique vapor deposition, and a display device using the liquid crystal display element, for example, a projection display such as a projector. It can be used for devices, liquid crystal monitors, liquid crystal televisions and the like.

It is the schematic which shows the liquid crystal device of this invention. It is the schematic which shows the splay alignment state in the display area of the liquid crystal device of this invention. It is the schematic which shows the bend alignment state in the non-display area | region of the liquid crystal device of this invention. It is the schematic which shows the boundary part of the 1st inorganic alignment film and the 2nd inorganic alignment film in the liquid crystal device of this invention. It is the schematic which shows the pretilt angle in the liquid crystal device of this invention. It is the schematic of the oblique vapor deposition method in the manufacturing method of the liquid crystal device of this invention. It is the schematic of an example of the oblique vapor deposition method in the manufacturing method of the liquid crystal device of this invention. It is the schematic which shows an example of the measuring method of the voltage-reflectance measurement of the liquid crystal device of this invention. 4 is a graph showing the relationship between the thickness of an inorganic alignment film and the pretilt angle in the liquid crystal device of the present invention. It is a graph which shows the voltage-reflectance characteristic curve in the liquid crystal device of the Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 101 Pixel electrode 102 Transfer electrode 103 Seal part 104 Sealing part 105 Extraction electrode 106 Display area 107 Non-display area 201 Upper substrate 202 Lower substrate 203 First inorganic alignment film 204 Liquid crystal layer A
205 Pixel electrode 206 Lower substrate 301 Second inorganic alignment film 302 Liquid crystal layer B
401 Transition electrode 402 Liquid crystal layer 1
403 Liquid crystal layer 2
501 Pretilt angle θp
502 Liquid Crystal Molecule 503 Liquid Crystal Alignment Film 504 Glass Substrate 601 Deposition Source 602 Deposition Substrate 603 Substrate Transport Mechanism 604 Substrate Normal 605 Deposition Angle 606 Deposition Distance 701 Ion Source 702 Ion Beam Irradiation Angle 801 Half Mirror 802 Phase Plate 803 Liquid Crystal Device 804 Light source 805 Polarizing plate 1
806 Polarizing plate 2

Claims (12)

  A liquid crystal device for controlling retardation of a liquid crystal layer by a voltage applied to the liquid crystal layer, wherein the liquid crystal layer is composed of a nematic liquid crystal having positive dielectric anisotropy, and at least one of the liquid crystal layers sandwiched and opposed to each other A pair of substrates through which the substrate transmits light, a display region portion in which a plurality of pixel electrodes are arranged on one of the pair of substrates, and a non-display region portion that is a region other than the display region A counter electrode made of a transparent electrode is disposed on the other substrate, the liquid crystal layer side of the pair of substrates has an inorganic alignment film mainly composed of an inorganic material, and the at least one substrate The liquid crystal device according to claim 1, wherein the inorganic alignment film disposed on the substrate has a plurality of regions having different thicknesses of the inorganic alignment film.   The liquid crystal device according to claim 1, wherein the alignment state during display operation of the liquid crystal layer is bend alignment.   2. The thickness of the inorganic alignment film in the display region portion is smaller than the thickness of the inorganic alignment film in the non-display region portion among the plurality of regions having different thicknesses of the inorganic alignment film. 2. A liquid crystal device according to 2.   4. The liquid crystal device according to claim 1, wherein in the liquid crystal layer on the non-display region, the alignment state of the liquid crystal layer when no voltage is applied is bend alignment. 5.   The liquid crystal device according to claim 1, wherein an electrode that does not contribute to display is disposed in the non-display area portion.   The shape of the display area is a rectangle, and electrodes that do not contribute to display and are arranged in the non-display area are formed along each side of the display area. A liquid crystal device according to any of the above items.   7. The azimuth direction of the oxide columnar structure constituting the inorganic alignment film is inclined in the same direction in a plurality of regions having different film thicknesses. The liquid crystal device according to item.   A method of manufacturing a liquid crystal device that controls retardation of a liquid crystal layer by a voltage applied to the liquid crystal layer, the step of forming a first inorganic alignment film on a pair of substrates, and at least one of forming the inorganic alignment film Forming a second inorganic alignment film with a film formation region limited on the substrate. A method for manufacturing a liquid crystal device, comprising:   The liquid crystal device according to claim 8, wherein the step of forming the second inorganic alignment film in which the film formation region is limited is a step of forming the second inorganic alignment film only in the non-display region. Production method.   10. The method for manufacturing a liquid crystal device according to claim 8, wherein the first and second inorganic alignment films are formed by oblique vapor deposition.   11. The method according to claim 8, wherein the method of limiting the film formation region is a method of placing a mask having an opening on a substrate on which a first inorganic alignment film is formed. A manufacturing method of the liquid crystal device according to the description.   12. The method of manufacturing a liquid crystal device according to claim 11, wherein the mask blocks at least a display area.

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