Patent Publication Number: US-2009237604-A1

Title: Liquid crystal display device and method for manufacturing the same, and electronic apparatus

Description:
The entire disclosure of Japanese Patent Application No. 2008-069225, filed Mar. 18, 2008 is expressly incorporated by reference herein. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a liquid crystal display device and a method for manufacturing the same, and an electronic apparatus. 
     2. Related Art 
     In recent years, a vertical alignment method has been increasingly employed in a liquid crystal display device for a projector as a liquid crystal alignment method. However, in the vertical alignment method, the liquid crystal molecule aligned vertically with respect to a substrate surface, and has poor interaction in an azimuth direction of tilting when a voltage is applied. Therefore, when the voltage is applied, the liquid crystal molecule tilts in various directions by a lateral electric field generated at an end portion of an electrode. In some directions, the liquid crystal does not contribute to a display (liquid crystal molecules parallel to a transmission axis of any of polarizing plates do not cause a phase difference in a crossed Nicol state) so as to cause a problem that a transmittance is lower than the transmittance in a parallel alignment. 
     JP-A-10-161127 is a first example of related art. In order to prevent the abnormal alignment due to the lateral electric field, a method which makes less leakage of light is disclosed in the first example by making a pretilt angle of a pixel electrode smaller than the pretilt angle of a counter substrate. The pretilt angle of the pixel electrode requires a strong alignment regulating force. However, a substantial average tilt angle which prevents the abnormal alignment due to the lateral electric field is almost same as the tilt angle in a condition of mass production, and the effect of contrast is hardly improved. The alignment layer disposed at a facing surface of both substrates is formed by an oblique evaporation. A plurality of expensive apparatuses such as vacuum deposition system are required when the liquid crystal display device is mass produced. Accordingly, a huge initial investment is required. 
     JP-A-2002-296597 is a second example of related art. In the second example, a method that prevents alignment defects caused by the lateral electric field when a liquid crystal display method is in a TN-mode is disclosed. In the method, an inorganic alignment layer is formed by the oblique evaporation at an active matrix substrate while an organic alignment layer is formed by a printing method or a coating process which are conventional mass production methods at a counter substrate. 
     In the second example of related art, the alignment layer at the counter substrate sis formed by the printing method or the coating process which are the conventional mass production methods. Accordingly, the capital investment can be reduced. However, polyimide which is capable of coating and is for the vertical alignment is hard to be tilted from a completely vertical state by a rubbing treatment. For a small or a medium size liquid crystal display device of a viewfinder type, or a large size liquid crystal display device, a direction of a tilt (an incline) when applying the voltage is determined by the lateral electric field generated at the end portion of the electrode and a protrusion included to an electrode surface. In the method, almost invariably, a disclination line caused by conflicts between liquid crystal molecules in a pixel occurs. However, the disclination line is unrecognizable since a size of the pixel is several dozen μm. As for a HTPS(High Temperature Poly Silicone) panel and an LCOS(Liquid Crystal on Silicone) panel which are liquid crystal panels having the size around 10 μm used for a light valve of the projector, the disclination line is visually recognized on projector screen so that a display quality is lowered. 
     SUMMARY 
     An advantage of the invention is to provide a liquid crystal display device having a good contrast characteristic while preventing display failures such as disclination lines and enabling costs to be reduced, a method for manufacturing the liquid crystal display device, and an electronic apparatus using the device. 
     By forming an inorganic alignment layer having an alignment regulating force such as a pretilt angle and an azimuthal angle at a circuit substrate by an oblique evaporation and applying a vertical alignment layer formed by a coating process at a counter substrate, the inventor has proposed a manufacturing method having an excellent productive efficiency. The method allows reducing the number of vacuum deposition systems and greatly reducing the initial investment. However, the alignment layer having different elements is used for both substrates so that electrical asymmetry (LCcom variation) occurs between the substrates. When the voltage applied to each frame is different, an impurity in the liquid crystal gathers about one of the alignment layers, and a transmittance of each frame varies. It causes flickers. The LCcom variation causes a problem of display failures such as image sticking when the same image is kept displaying for a period of long time. The problem significantly degrades a display quality. Therefore, the invention will be proposed as follows. 
     According to a first aspect of the invention, a liquid crystal display device, includes: a circuit substrate; a counter substrate oppositely disposed to the circuit substrate; a liquid crystal layer which is sandwiched between the circuit substrate and the counter substrate, and shows a vertical alignment in an initial state; a first alignment layer having an alkyl chain formed by a coating process at a liquid crystal layer of the counter substrate; and a second alignment layer formed by a vacuum deposition process at the liquid crystal layer of the circuit substrate. In the device, an alkyl chain is further bonded on a surface of the second alignment layer. 
     According to the invention, bonding the alkyl chain on a surface of the second alignment layer enables a difference between the second and the first alignment layers to be reduced. The second alignment layer is formed by the vacuum deposition process at the circuit substrate. The first alignment layer is formed by the coating process at the counter substrate, and has the alkyl chain. Accordingly, a voltage difference of each frame applied between the counter substrate and the circuit substrate can be reduced. As a result, the LCcom variation is stabilized and flickers hardly occur on the displaying image. In addition, display failures such as image sticking hardly occur when the same image display is kept for a long period of time. Thus, the vertical alignment type liquid crystal display having a superior display quality can be obtained. 
     According to a second aspect of the invention, a method for manufacturing a liquid crystal display device which sandwiches a liquid crystal layer between a circuit substrate and a counter substrate includes: forming a first alignment layer having a linear alkyl chain which is formed by a coating process at a liquid crystal layer of the counter substrate; forming a second alignment layer by a vacuum deposition process at the liquid crystal layer of the circuit substrate; and bonding a linear alkyl chain to a surface of the second alignment layer. 
     According to the invention, bonding the alkyl chain on the surface of the second alignment layer (an oblique evaporation layer) enables the difference between the second and the first alignment layers to be reduced. The second alignment layer is formed by the vacuum deposition process at the circuit substrate. The first alignment layer is formed by the coating process at the counter substrates, and has the alkyl chain. Therefore the difference in dielectric anisotropy at the counter substrate, the circuit substrate, and each alignment layer is reduced, and a voltage difference in every frame applied between the counter substrate and the circuit substrate can also be reduced. Accordingly, the difference of an effective voltage applied on an electrode under the alignment layer by reversing polarity per a frame is reduced. As a result, the LCcom variation is stabilized, and flickers and image sticking hardly occur when the same display image is kept for a long period of time. Thus, the vertical alignment type liquid crystal display having a superior display quality can be obtained. 
     In the bonding the alkyl chain to the surface of the second alignment layer, it is preferable that the second alignment layer be surface-treated with a silane coupling agent which includes a linear alkyl group having 6 to 20 carbon atoms. According to the invention, the alkyl chain can be bonded in a state that a shape (a pretilt) of the second alignment layer (oblique evaporation layer) formed by the vacuum process is reflected. The alkyl chain having less than 6 carbon atoms lowers an alignment uniformity of liquid crystal molecules than adopting oblique evaporation. On the other hand, the alkyl chain having more than 20 carbon atoms causes uneven bonding. 
     According to a third aspect of the invention, an electronic apparatus includes the liquid crystal display device described as above. The invention can provide the electronic apparatus having a high quality display with low costs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention will be described with reference to the accompanying drawings, wherein like numbers reference like elements. 
         FIG. 1  is a sectional view schematically showing an element structure of a liquid crystal display device according to an embodiment of the invention. 
         FIG. 2  is a sectional view schematically showing a first and a second alignment layers. 
         FIG. 3  is a partially enlarged view showing an enlarged part (P indicated with a broken line) of  FIG. 2 . 
         FIG. 4  is the partially enlarged view showing the enlarged part (Q indicated with a broken line) of  FIG. 2 . 
         FIG. 5  is a perspective view schematically showing examples of electronic equipments of the invention. 
     
    
    
     DESCRIPTION OF EXEMPLARY EMBODIMENTS 
     Embodiments of the invention will now be described below with reference to the accompanying drawings. In the accompanying drawings, the layer thickness and the scale of each element is adequately changed so as to provide each member in a recognizable size. 
     Liquid Crystal Display device 
     A liquid crystal display device of an embodiment of the invention is a transmissive liquid crystal display device of an active matrix type using thin-film transistors (TFTs) as switching elements. 
       FIG. 1  schematically shows a sectional structure of the liquid crystal display device. The sectional structure (a pixel structure) of the liquid crystal display device of the embodiment is described with reference to  FIG. 1 . A liquid crystal panel  50  includes a circuit substrate  10 , a counter substrate  20  oppositely disposed to the circuit substrate  10 , and a liquid crystal layer  58  sandwiched between the circuit substrate  10  and the counter substrate  20 . The liquid crystal layer  58  is made of a liquid crystal material that shows a vertical alignment in an initial state, and has negative dielectric anisotropy. The circuit substrate  10  includes a substrate body  10 A and a pixel electrode  9  formed on an inner surface of the substrate body  10 A. The substrate body  10 A is made of a transparent material such as glass. The pixel electrode  9  is made of a transparent conductive material such as indium tin oxide (hereinafter abbreviated as “ITO”) and has a rectangular shape. The circuit substrate  10  also includes TFT elements serving as switching elements for controlling energization of the pixel electrodes  9 , date lines through which image signals are supplied, scan lines, and the like (all not shown), and may include a function of a light-shielding layer. 
     The counter substrate  20  includes a substrate body  20 A and a common electrode  21 . The substrate body  20 A is made of the transparent material such as glass. The common electrode  21  is formed on the inner surface of the substrate body  20 A, and is made of a transparent conductive layer such as ITO. The common electrode  21  is not divided corresponding to each pixel region, and flatly and entirely formed on the substrate body  20 A. The counter substrate  20  also may include color filters and light-shielding layers. 
     The counter substrate  20  also includes a first alignment layer  22  having vertical alignment property so as to cover the common electrode  21  while the circuit substrate  10  includes a second alignment layer  11  having a pretilt so as to cover a plurality of the pixel electrodes  9 . In the liquid crystal layer  58  sandwiched between the counter substrate  20  and the circuit substrate  10 , liquid crystal molecules  52  are vertically aligned in an initial state (in which no voltage is applied) therebetween. 
     Here, the second alignment layer  11  of the circuit substrate  10  is distinctive elements of the invention. That is, in the invention, the second alignment layer  11  is composed of an inorganic layer  12   a  and a surface layer  12   b  which is composed of any functional group. The specific structures of the first alignment layer  22  and the second alignment layer  11  are described with reference to  FIG. 2  in which the structures of the first alignment layer  22  and the second alignment layer  11  are schematically shown.  FIG. 3  is a partially enlarged view showing an enlarged part (P indicated with a broken line) in  FIG. 2 .  FIG. 4  is the partially enlarged view showing the enlarged part (Q indicated with the broke line) in  FIG. 2 . 
     First Alignment Layer 
     As shown in  FIGS. 2 and 3 , the first alignment layer  22  shows nearly the vertical alignment without any specific azimuthal angle, and modifies a surface of the common electrode  21  with a linear alkyl chain  28 A. The first alignment layer  22  can be obtained by coating the substrate body  20 A with an alignment layer material using a coating process such as a spin coating and a flexographic printing. 
     Examples of the alignment layer forming material include a vertical alignment type of polyimide which is commonly used as a vertical alignment agent, a compound that can self-assemble such as a silicon based compound and an organic silane. The silicon based compound and the organic silane include a region that can be chemically adsorbed (bonded) to the substrate (e.g., an alkoxy group forms a silanol group by hydrolysis) and a part having a vertical alignment towards the liquid crystal molecules (e.g., an alkyl group having 10 to 20 carbon atoms). 
     Second Alignment Layer 
     As shown in  FIG. 2 , the second alignment layer  11  includes the inorganic layer  12   a  and the surface layer  12   b.  The inorganic layer  12   a  is obtained by depositing the alignment layer material on the substrate body  10 A by an oblique evaporation. Examples of the material for the second alignment layer  11  include a silicic compound of SiO 2  or SiO and a metal oxide such as Al 2 O 3 , ZnO, MgF, or ITO. 
     As shown in  FIG. 4 , the surface layer  12   b  is formed on the inorganic layer  12   a,  and is composed mainly of an alkyl chain  28 B having 6 to 20 carbon atoms bonded to a Si atom of the inorganic layer  12 . 
     As shown in  FIGS. 2 and 4 , the alkyl chain  28 B roughly reflects a surface shape of the oblique evaporation (the inorganic layer  12   a ). That is, since the alkyl chain  28 B is nearly extended (bonded) along a shape of the inorganic layer  12   a  (an oblique evaporation layer), the alkyl chain  28 B has the pretilt similarly to that of the oblique evaporation. Although the alkyl chain  28 B may have a slight variation of the pretilt angle, the original state of the oblique evaporation is kept in the azimuthal angle. 
     The alkyl chain having less than 6 carbon atoms causes lowering of an alignment uniformity of the liquid crystal, thereby the alkyl chain may not function as the alignment layer. When the alkyl chain having more than 20 carbon atoms is used, steric hindrance between the adjacent alkyl chains become too large so that the alkyl chain  28 B is bonded unevenly on the inorganic layer  12   a.  The alkyl chain having 6 to 20 carbon atoms reflects a large part of the pretilt of the inorganic layer  12   a  due to the influence of steric hindrance of the alkyl chains  28 B adjacent to each other on the inorganic layer  12   a.    
     The inorganic layer  12   a  is surface-treated with a silane coupling agent which includes the alkyl group having a predetermined number of carbon atoms so as to form the surface layer  12   b  on the inorganic layer  12   a,  thereby the inorganic layer  12   a  and the surface layer  12   b  serve as the second alignment layer  11 . The surface layer  12   b  is composed of the alkyl chain  28  (organic substances). Consequently, the second alignment layer  11  has the same organic group as a structure of the first alignment layer  22  so as to reduce asymmetry of an alignment layer component. 
     The liquid crystal layer  58  is sandwiched between the circuit substrate  10  and the counter substrate  20 . The liquid crystal layer  58  shows the vertical alignment in the initial state by the first alignment layer  22  and the second alignment layer  11 . In addition, a pair of polarizing plates  61  and  62  disposed on both sides of the liquid crystal panel  50  in such a manner that a polarization axis of the polarizing plate  61  makes an angle of about 45 degrees with respect to an azimuthal angle of the liquid crystal while the polarization axis of the polarizing plate  62  makes the angle of about 135 degrees with respect to azimuthal angle of the liquid crystal. The polarization axes of the polarizing plates  61  and  62  are almost orthogonal to each other. Further, a light source unit (not shown) is disposed below the polarizing plate  61 . The liquid crystal display device  100  of the embodiment is thus structured. 
     In the liquid crystal display device  100  structured as above, when no voltage is applied, the liquid crystal molecules  52  at an interface are vertically aligned, and make an angle about 90 degrees with respect to a substrate surface by the first alignment layer  22  at a counter substrate  20  side. The liquid crystal molecules  52  at the interface are vertically aligned and make a predetermined pretilt angle with respect to the substrate surface by the second alignment layer  11  at a circuit substrate  10  side. Thus, the liquid crystal molecules  52  sandwiched by the counter substrate  20  and the circuit substrate  10  are vertically aligned with respect to the substrate surface. 
     The voltage is applied between the pixel electrode  9  and the common electrode  21  so that the liquid crystal molecules  52  of the liquid crystal layer  58  can be tilted almost parallel to the substrate surface. 
     In the embodiment, the alkyl group which the first alignment layer  22  includes is also formed on the inorganic alignment layer of the second alignment layer  11 . Accordingly, when the voltage is applied between the common electrode  21  and the pixel electrode  9 , a dielectric constant between both substrates  10  and  20  can be balanced. That is, if the structure of each of the alignment layers  22  and  11  in the liquid crystal panel  50  is different, impurity ions and the like in the liquid crystal layer  58  are eccentrically gathered at one side of the alignment layer. Therefore, the voltage applied between the pixel electrode  9  and the common electrode  21  is asymmetric so that display failures such as flickers and image sticking can easily occur. However, the structure of each of the alignment layers  22  and  11  is the same, so that electrical asymmetry between the both substrates  10  and  20  hardly occurs. Therefore, it is possible to stabilize LCcom variation in a long term drive so as to improve a display quality. 
     Manufacturing Method 
     A method for manufacturing the liquid crystal display device according to the embodiment of the invention will be described. 
     First, the substrate body  20 A having a transparency and made of glass or the like is prepared. Then, a light-shielding layer (not shown) and the common electrode  21  are formed by a known method. Then, the first alignment layer  22  is formed on the common electrode  21 . The first alignment layer  22  is formed by coating the counter substrate  20  with the alignment layer material having a long-chain alkyl group by the spin coating and the flexographic printing. Then a chemical reaction of the common electrode  21  made of ITO with the alkyl group enables a self-assembled monolayer (SAM) to be formed on the substrate body  20 A. The SAM covers the common electrode  21 . 
     Specifically, the substrate body  20 A is coated with an octadecyltrimethoxysilane (ODS) methanol solution in an N 2  atmosphere so as to form the SAM having the alkyl group (an octadecyl group) on the common electrode  21  as shown in  FIG. 3 . The first alignment layer  22  is thus formed on the substrate body  20 A. The first alignment layer  22  has an organic/inorganic hybrid structure which having Si as a main chain backbone. In addition, the self-assembled monolayer (the first alignment layer  22 ) can be formed by other known method. 
     The coating process is not particularly limited. Various methods can be employed in addition to the method described above. A dipping method (dip coating method), the spray coating method, various printing methods, and an inkjet method are preferably used. 
     Then, the substrate body  10 A having the transparency and made of glass or the like is prepared. Then, the light-shielding layer, a semiconductor layer, various wiring lines such as the scan lines and the data lines (all not shown), and the pixel electrode  9  are formed by the known method. As shown in  FIGS. 1 and 2 , the oblique evaporation layer is formed on the pixel electrode  9  with a vacuum deposition system so as to obtain the inorganic layer  12   a  which composes the second alignment layer  11 . In the vacuum deposition system, the substrate body  10 A is set so that an angle between a face on which the layer is formed and an incident direction of the layer material with respect to the face on which the layer is formed is less than 90 degrees. As a result, an orthorhombic crystal is grown on the face on which the layer is formed so as to form the layer having a desired oblique evaporation columnar structure (the pretilt). After the inorganic layer  12   a  is thus formed on the substrate body  10 A, the inorganic layer  12   a  is surface-treated. 
     As for the surface treatment, the substrate body  10 A having the inorganic layer  12   a  is dipped into the silane coupling agent solution having the long-chain alkyl group for a predetermined time. Here, the silane coupling agent includes an organic functional group and a hydrolysis group in a single molecule, by which in organic substances and organic substances are combined, enabling the physical strength, durability, and adhesiveness of a material to improve. Specifically, it is represented by the following chemical formula. An organic functional group and 2 to 3 organic groups reacting with an inorganic substance are bonded to a silicon atom (Si). 
     Chemical Formula 
     
       
         
         
             
             
         
       
         
         
           
             X: hydrolysis group bonded to silicon atom 
           
         
       
    
     
       
         
         
             
             
         
       
     
     and the like (R is alkyl group)
         Y: organic functional group which reacts with organic matrix, —R and the like       

     The silane coupling agent to be used is not particularly limited as long as the organic functional group has good repellency and a light durability. Specifically, one having an alkyl group as an organic functional group (Y) in the chemical formula is preferably used. The hydrolysis group is also not particularly limited. A group having a small molecular weight such a methoxy group (—O—CH 3 ) or an ethoxy group (—O—C 2 H 5 ) is preferably used since they are not easy to cause steric hindrance when they are reacted with and added to the surface of the inorganic layer  12   a.    
     When the silane coupling agent is brought into contact with the surface of the inorganic layer  12   a,  as shown in  FIGS. 2 and 4 , the alkyl chain  28 B is bonded along an oblique evaporation columnar structure of the inorganic layer  12   a.  At this time, since a long-chain of the alkyl group is extended in a direction of an orthorhombic crystal growth, the alkyl chain  28 B also has the similar pretilt (the alignment regulating force on the liquid crystal molecules  52 ) as the inorganic layer  12   b  has. 
     Thus, the surface of the inorganic layer  12   a  is modified with the alkyl chain  28 B so as to obtain the surface layer  12   b  made of the organic substances on the inorganic layer  12   a.  Accordingly, the second alignment layer  11  can be obtained. The second alignment layer  11  has the same structure as the first alignment layer  22  which can be formed by the coating process of the counter substrate  20 , i.e., the organic/inorganic hybrid alignment layer. Therefore, electrical asymmetry between the both substrates  10  and  20  hardly occurs, thereby a uniform display without abnormal displays can be achieved. 
     As for the surface treatment with the silane coupling agent, a chemical vapor deposition method also can be employed as well as a liquid coating method described above. In the chemical vapor deposition method, the substrate body  10  having the inorganic layer  12   a  may be put into a chamber capable of being tightly closed, and then the silane coupling agent may be introduced into the chamber as steam for the surface treatment. 
     Specifically, as an example, the substrate body  10  having the inorganic layer  12   a  is dried at about 150 to about 180 degrees centigrade for about 3 hours in the N 2  atmosphere. Then the substrate body  10 A is left inside the tightly closed chamber together with a container holds, for example, the ODS solution therein. The container is heated, for example, at 150 degrees centigrade for about 1 hour, whereby vapor of the ODS solution comes into contact with the surfaces of the inorganic layer  12   a  of the substrate body  10 A. As a result, the long-alkyl group of the ODS molecule is bonded on the inorganic layer  12   a  since the long-alkyl group includes an inorganic reactive group. The surface layer  12   b  is thus formed on the inorganic layer  12   a  so as to obtain the second alignment layer  11 . 
     In the vertical alignment type liquid crystal display device  100  of the embodiment, the self-assembled monolayer is formed by the coating process at the counter substrate  20  so as to obtain the first alignment layer  22  (a vertical alignment layer) which has the organic/inorganic hybrid structure. On the other hand, the inorganic layer  12   a  having the pretilt is formed by the oblique evaporation method at the circuit substrate  10 . Then, the surface layer  12   b  is formed on the inorganic layer  12   a  by the surface treatment with the silane coupling agent. As a result, the second alignment layer  11  has the same organic/inorganic hybrid structure as the first alignment layer  22  described above. As described, the alignment layers  11  and  22  have the same elements so that the voltage applied to the circuit substrate  10  and the counter substrate  20  is almost equal. It allows stabilizing the LCcom variation so as to obtain the liquid crystal display device  100  having a superior display quality without display failures such as the image sticking when the same image display is kept for a long period of time. 
     In addition, one of the substrates that compose the liquid crystal panel  58 , the first alignment layer  22  of the counter substrate  20  here, is formed by the coating process so as to reduce the number of the vacuum deposition system used for manufacturing the liquid crystal display device  100 . Since the number of the vacuum layer forming apparatuses used is reduced, massive investment becomes unnecessary, and the first alignment layer  22  can be formed with a high productivity by conventional alignment layer coating apparatuses. Consequently, a vertically aligned light valve having a superior display quality can be provided with low costs. 
     EXAMPLE 1  
     At the circuit substrate  10 , the second alignment layer  11  was formed by the oblique evaporation method so as to give the alignment regulating force on the pretilt angle and the azimuthal angle of the liquid crystal molecules  52 . Further, 1 wt % of a solution of an octadecyltrimethoxysilane/methanol was adjusted. The circuit substrate  10  was dipped into the solution at room temperature for 30 minutes, and then taken out. The substrate was cleaned with dekalin, and then heated at 120 degrees centigrade for 1 hour in a heated oven. 
     At the counter substrate  20 , the substrate body  20 A was coated with the solution of organic/inorganic hybrid material which having Si as the main chain backbone. 
     The circuit substrate  10  and the counter substrate  20  completed as described above were bonded. A liquid crystal material which has negative dielectric anisotropy was injected through an injection hole, and then the injection hole was sealed to complete the liquid crystal panel  50 . Then, the polarizing plates  61  and  62  were bonded in such a manner that their transmission axes respectively make angles of about 45 degrees and about 135 degrees with respect to the alignment direction of the liquid crystal panel  50  (the azimuthal angle of the liquid crystal molecules  52  is 0 degree), whereby the liquid crystal display device  100  was completed. 
     An electric signal was inputted to the liquid crystal display device  100 , and the voltage on the pixel electrode  9  was turned on and off. When the voltage was turned on, a bright uniform white display was obtained in each pixel. When the voltage was turned off, a black display with less leakage of light due to the vertical alignment could be obtained. A black window was kept displaying in a whole white display screen for about 10 hours, then the screen was turned to the whole white display again. The uniform white display without any display hysteresis of the black window could be provided. 
     Electronic Apparatus 
     Examples of electronic apparatus equipped with the liquid crystal display device of the embodiment will be described.  FIG. 5A  is a perspective view showing an example of cellular phones. In  FIG. 5A , a cellular phone  500  has a liquid crystal display  501  using the liquid crystal display device of the embodiment. 
       FIG. 5B  is a perspective view showing an example of portable information processing units such as a word processor and a personal computer. In  FIG. 5B , an information processing unit  600  includes: an input section  601  such as a keyboard; an information processing unit  603 ; and a liquid crystal display  602  using the liquid crystal display device of the embodiment. 
       FIG. 5C  is a perspective view showing an example of wristwatch type electronic apparatuses. In  FIG. 5C , a watch  700  includes a liquid crystal display  701  using the liquid crystal display device of the embodiment. 
     The electronic apparatuses shown in  FIGS. 5A to 5C  employ the liquid crystal display device, which is an example of the invention as displays. Therefore, the electronic apparatuses can maintain a high contrast and a high quality display for a long period of time without problems of displaying rubbing stripes caused by a rubbing process, for example. 
     The preferred embodiment of the invention has been described with reference to the accompanying drawings as above. The invention is not limited to the embodiment, and the examples and the embodiment may be combined. Naturally, those skilled in the art will be able to presume many variations and modifications within the purview of the technical idea disclosed in the scope of claims of the invention. It will be understood that those variations and modifications are obviously within the technical scope of the invention. 
     In the above embodiment, a coating type vertical alignment layer is formed with the SAM. However, it is not particularly limited to this.