JP2020042057A - Liquid crystal device, method of manufacturing liquid crystal device, and electronic apparatus - Google Patents

Abstract

To provide a liquid crystal device, a manufacturing method for the liquid crystal device, and an electronic apparatus with which it is possible to cover the drawbacks of an ion-assist vapor deposition film while taking advantage of such characteristics that a photochemical reaction hardly occurs when the ion-assist vapor deposition film is used for alignment films.SOLUTION: A first alignment film 16 and a second alignment film 26 individually comprise: first inorganic films 161, 261 (first columnar structure 51) formed by an ordinary vacuum deposition method; a second inorganic films 162, 262 (second columnar structure 52) formed by an ion-assist vapor deposition method; and third inorganic films 163, 263 (third columnar structure 53) formed by an ordinary vacuum deposition method. The second columnar structure 52 is of low density and has a narrow surface area, so that a contact area with a liquid crystal layer 80 is narrow. Therefore, a photochemical reaction between a liquid crystal layer 80 and itself hardly occurs. The second columnar structure 52 has some drawbacks such as a tendency of ion density to increase, but these drawbacks are covered by the upper third columnar structure 53.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a liquid crystal device having an inorganic alignment film, a method for manufacturing a liquid crystal device, and an electronic apparatus having the liquid crystal device.

  The liquid crystal device includes a first substrate provided with a plurality of pixel electrodes and a first alignment film on one side, and a second substrate provided with a common electrode and a second alignment film on one side facing the first substrate. And a liquid crystal layer provided between the first substrate and the second substrate, and are often used as light modulation means (light valves) of a projection display device such as a projector. In a liquid crystal device, it has been proposed to form an inorganic material such as silicon oxide by oblique deposition in order to improve the heat resistance of the first alignment film and the second alignment film. Is formed as a columnar structure including a plurality of columns.

  However, when the inorganic alignment film is composed of a silicon oxide film, dangling bonds of Si atoms and a dimer structure in which Si atoms are bonded to each other (Si-Si bond) exist. A bond is easily terminated by a silanol group (—Si—OH) by a reaction with moisture or the like in a liquid crystal or atmosphere. Such a silanol group has high reactivity, and therefore, when irradiated with strong light, a photochemical reaction easily occurs between the silanol group and the liquid crystal material. When such a photochemical reaction is repeated, the alignment control force of the liquid crystal molecules by the inorganic alignment film decreases, and the display performance of the liquid crystal device gradually decreases.

  On the other hand, in forming an inorganic alignment film, a structure in which a lower inorganic alignment film is formed by a substrate heating evaporation method, which is a normal vacuum evaporation method, and then an upper inorganic alignment film is formed using an ion-assisted evaporation method. It has been proposed (see Patent Document 1). Further, it has been proposed to perform a silane coupling treatment (hydrophobic treatment) on the upper inorganic alignment film.

JP 2010-78997 A

  Since an inorganic alignment film formed by an ion-assisted evaporation method (hereinafter, referred to as an ion-assisted evaporation film) tends to have a structure in which columns are in contact with each other, an inorganic alignment film formed by a substrate heating evaporation method (hereinafter, referred to as a normal evaporation film) ) And denser. For this reason, the ion-assisted vapor-deposited film has a smaller surface roughness than the normal vapor-deposited film, and thus has a smaller contact area with the liquid crystal layer. Therefore, the use of the ion-assisted vapor deposition film has an advantage that a photochemical reaction between the silanol group and the liquid crystal material hardly occurs. However, since the ion-assisted vapor deposition film is active, there is a problem that the ion density is increased and charge leakage easily occurs when driving the liquid crystal. Also, in order to properly align the liquid crystal molecules, the outermost surface of the alignment film needs to have an appropriate roughness. However, the ion assisted evaporation film has a small surface roughness, and the surface area of the evaporation film is small. Is also small. For this reason, there is a problem that the alignment regulating force for the liquid crystal molecules is small.

  In view of the above problems, an object of the present invention is to cover the disadvantages of an ion-assisted vapor deposition film while taking advantage of the fact that a photochemical reaction is unlikely to occur when an ion-assisted vapor deposition film is used as an alignment film. An object of the present invention is to provide a liquid crystal device, a method of manufacturing the liquid crystal device, and an electronic device that can be used.

  In order to solve the above problem, one embodiment of a liquid crystal device according to the present invention is a first inorganic film, and a second inorganic film stacked on the liquid crystal layer side of the first inorganic film and having a higher density than the first inorganic film. A third inorganic film laminated on the liquid crystal layer side of the second inorganic film and having a lower density than the second inorganic film.

  In one embodiment of the method for manufacturing a liquid crystal device according to the present invention, in the step of forming an alignment film, a first film forming step of forming a first inorganic film by a vacuum deposition method without using ion assist; A second film forming step of laminating a second inorganic film on the film by ion-assisted vapor deposition; and a third film forming step of laminating a third inorganic film on the second inorganic film by vacuum deposition without ion assist. And a film process.

  The liquid crystal device to which the present invention is applied can be used for various electronic devices such as a direct-view display device and a projection display device.

FIG. 2 is a plan view illustrating one embodiment of a liquid crystal device to which the present invention is applied. FIG. 2 is a cross-sectional view taken along line HH ′ of the liquid crystal device illustrated in FIG. 1. FIG. 2 is a cross-sectional view schematically illustrating a specific configuration example of a pixel of the liquid crystal device illustrated in FIG. 1. FIG. 2 is an explanatory diagram schematically showing a first alignment film and a second alignment film of the liquid crystal device shown in FIG. 1 in an enlarged manner. Explanatory drawing which expands and shows typically the cross section of the 1st columnar structure shown in FIG. 5 is an electron micrograph showing an enlarged surface of the first columnar structure shown in FIG. 4. FIG. 5 is an electron micrograph showing an enlarged surface of the second columnar structure shown in FIG. 4. 5 is an electron micrograph showing an enlarged cross section of the second columnar structure shown in FIG. 4. FIG. 2 is an explanatory diagram of a projection display device (electronic device) using a liquid crystal device to which the present invention is applied.

  Embodiments of the present invention will be described with reference to the drawings. In the drawings referred to in the following description, the scale of each layer and each member is different for each layer and each member in order to make the size recognizable in the drawings. Further, when describing the layer formed on the first substrate, the upper layer side or the front side means the side opposite to the side where the substrate body of the first substrate is located (the side where the opposing substrate and the electro-optical layer are located). The lower layer means the side of the first substrate where the substrate body is located. When describing the layer formed on the second substrate, the upper layer side or the front side means the side opposite to the side where the substrate body of the opposing substrate is located (the side where the first substrate and the electro-optical layer are located), The lower layer side means a side of the second substrate where the substrate body is located.

(Overall Configuration of Liquid Crystal Device 100)
FIG. 1 is a plan view illustrating one embodiment of a liquid crystal device to which the present invention is applied. FIG. 2 is a sectional view taken along line HH ′ of the liquid crystal device shown in FIG.

  The liquid crystal device 100 shown in FIGS. 1 and 2 has a liquid crystal panel 100p. In the liquid crystal device 100, the first substrate 10 (element substrate) and the second substrate 20 (opposite substrate) are bonded to each other by a seal member 107 via a predetermined gap, and the seal member 107 is attached to an outer edge of the second substrate 20. It is provided in a frame shape so as to follow. The sealing material 107 is an adhesive made of a photo-curing resin, a thermosetting resin, or the like, and includes a gap material 107a such as glass fiber or glass beads for setting a distance between the two substrates to a predetermined value. In the liquid crystal panel 100p, between the first substrate 10 and the second substrate 20, a liquid crystal layer 80 is provided in a region surrounded by the sealant 107. A discontinuous portion 107c used as a liquid crystal injection port is formed in the sealant 107, and the discontinuous portion 107c is closed by a sealing material 108 after the injection of the liquid crystal material. Note that when the liquid crystal material is sealed by a dropping method, the discontinuous portion 107c is not formed.

  In the liquid crystal panel 100p, the first substrate 10 and the second substrate 20 are both rectangular, and the display area 10a is provided as a rectangular area substantially at the center of the liquid crystal panel 100p. Corresponding to such a shape, the sealing material 107 is also provided in a substantially rectangular shape, and the outside of the display region 10a is a rectangular frame-shaped outer peripheral region 10c.

  In the first substrate 10, of the outer peripheral region 10 c on the outer peripheral side of the display region 10 a, on the side where the first substrate 10 protrudes from the second substrate 20, the data line driving circuit 101 and the data line driving circuit 101 A plurality of terminals 102 are formed, and a scanning line driving circuit 104 is formed along another side adjacent to this one side. The terminal 102 is provided on the outer peripheral side of the sealing material 107. A flexible wiring board (not shown) is connected to the terminal 102, and various potentials and various signals are input to the first substrate 10 via the flexible wiring board. In this embodiment, the data line driving circuit 101 and the scanning line driving circuit 104 partially overlap the sealant 107 in plan view.

  The first substrate 10 has a translucent substrate main body 10w such as a quartz substrate or a glass substrate. Of the one surface 10s and the other surface 10t of the first substrate 10 (substrate main body 10w), the second substrate 20 A plurality of pixel switching elements and pixel electrodes 9a electrically connected to each of the plurality of pixel switching elements are formed in a matrix on the side of the one surface 10s opposite to the display area 10a. The first alignment film 16 is formed on the upper layer side of the pixel electrode 9a. On the side of the one surface 10s of the first substrate 10, a dummy frame formed simultaneously with the pixel electrode 9a is formed in a rectangular frame-shaped peripheral region between the display region 10a and the sealing material 107 in the peripheral region 10c. The pixel electrode 9b is formed.

  The second substrate 20 has a light-transmissive substrate main body 20w such as a quartz substrate or a glass substrate. Of the one surface 20s and the other surface 20t of the second substrate 20 (substrate main body 20w), the first substrate 10 The common electrode 21 is formed on the side of the one surface 20s opposite to. The common electrode 21 is formed substantially over the entire surface of the second substrate 20 or as a region including a plurality of band-shaped electrodes over a plurality of pixels 100a. In the present embodiment, the common electrode 21 is formed on substantially the entire surface of the second substrate 20.

  A light-shielding layer 29 is formed below the common electrode 21 on the one surface 20s side of the second substrate 20, and a second alignment film 26 is laminated on the surface of the common electrode 21 on the liquid crystal layer 80 side. Further, a translucent flattening film 22 is formed between the light shielding layer 29 and the common electrode 21. The light-shielding layer 29 is formed as a frame portion 29a extending along the outer peripheral edge of the display area 10a. The light-shielding layer 29 may be formed to include a black matrix portion (not shown) overlapping the inter-pixel region 10f sandwiched between the adjacent pixel electrodes 9a. In addition, a micro lens facing the pixel electrode 9a may be formed on the second substrate 20.

As described later, the first alignment film 16 and the second alignment film 26 include a silicon oxide film (SiO _X (x ≦ 2)), a titanium oxide film (TiO ₂₎ , a magnesium oxide film (MgO), and an aluminum oxide film ( It is an inorganic alignment film made of a deposited film of Al ₂ O ₃ ) or the like.

  In the liquid crystal panel 100p, the inter-substrate conduction electrode portions 24t are formed at four corners on the one surface 20s side of the second substrate 20 outside the sealant 107, and the one surface 10s of the first substrate 10 is formed. On the side of, an inter-substrate conduction electrode portion 6t is formed at a position facing the four corner portions (inter-substrate conduction electrode portion 24t) of the second substrate 20. The inter-substrate conduction electrode portion 6t is electrically connected to the constant potential wiring 6s to which the common potential Vcom is applied, and the constant potential wiring 6s is electrically connected to the common potential application terminal 102a among the terminals 102. An inter-substrate conducting material 109 containing conductive particles is disposed between the inter-substrate conducting electrode portion 6t and the inter-substrate conducting electrode portion 24t, and the common electrode 21 of the second substrate 20 is connected to the inter-substrate conducting member. It is electrically connected to the first substrate 10 side via the passing electrode portion 6t, the inter-substrate conducting material 109, and the inter-substrate conducting electrode portion 24t. For this reason, the common potential Vcom is applied to the common electrode 21 from the first substrate 10 side.

  The liquid crystal device 100 of the present embodiment is a transmission type liquid crystal device. Therefore, the pixel electrode 9a and the common electrode 21 are formed of a light-transmitting conductive film such as an ITO (Indium Tin Oxide) film or an IZO (Indium Zinc Oxide) film. In the transmissive liquid crystal device 100, for example, the light L incident from the second substrate 20 is modulated while being emitted from the first substrate 10 to display an image. When the common electrode 21 is formed of a light-transmitting conductive film and the pixel electrode 9a is a reflective electrode, the liquid crystal device 100 is configured as a reflective liquid crystal device. In such a liquid crystal device 100 (reflection type liquid crystal device), light incident from the second substrate 20 side is reflected by the pixel electrode 9a of the first substrate 10 and modulated again while being emitted from the second substrate 20 side. The image is displayed.

  The liquid crystal device 100 can be used as a color display device of an electronic device such as a mobile computer or a mobile phone. In this case, a color filter (not shown) is formed on the first substrate 10 or the second substrate 20. . Further, the liquid crystal device 100 can be used as a light valve for RGB in a projection display device (liquid crystal projector) described later. In this case, for example, light of each color separated via a dichroic mirror for RGB color separation is incident on each of the liquid crystal devices 100 for RGB as projection light, so that a color filter is formed. Not done.

(Specific Configuration of Pixel 100a)
FIG. 3 is a cross-sectional view schematically showing a specific configuration example of the pixel 100a of the liquid crystal device 100 shown in FIG. As shown in FIG. 3, on the one surface 10s side of the first substrate 10, a lower scanning line 3a made of a conductive film such as a conductive polysilicon film, a metal silicide film, a metal film or a metal compound film is formed. ing. In the present embodiment, the scanning line 3a is made of a light shielding film such as tungsten silicide (WSi). A translucent insulating film 11 is formed on an upper layer side of the scanning line 3a, and a pixel switching element 30 including a semiconductor layer 30a is formed on a surface side of the insulating film 11. In the present embodiment, the insulating film 11 is made of a silicon oxide film or the like.

  The pixel switching element 30 includes a semiconductor layer 30a and a gate electrode 30g crossing the semiconductor layer 30a, and has a light-transmitting gate insulating layer 30b between the semiconductor layer 30a and the gate electrode 30g. . The semiconductor layer 30a is composed of a polysilicon film (polycrystalline silicon film) or the like. The gate insulating layer 30b has a two-layer structure of a gate insulating layer made of a silicon oxide film obtained by thermally oxidizing the semiconductor layer 30a and a second gate insulating layer made of a silicon oxide film formed by a low pressure CVD method or the like. Gate electrode 30g is electrically connected via a contact hole (not shown) penetrating gate insulating layer 30b and insulating film 11.

  On the upper layer side of the gate electrode 30g, light-transmitting interlayer insulating films 12, 13, and 14 made of a silicon oxide film or the like are formed in order, and by using the space between the interlayer insulating films 12, 13, and 14, etc. A storage capacitor (not shown) is configured. A data line 6a and a drain electrode 6b are formed between the interlayer insulating film 12 and the interlayer insulating film 13, and a relay electrode 7a is formed between the interlayer insulating film 13 and the interlayer insulating film 14. The data line 6a is electrically connected to a source region of the semiconductor layer 30a via a contact hole 12a penetrating through the interlayer insulating film 12 and the gate insulating layer 30b. The drain electrode 6b is electrically connected to a drain region of the semiconductor layer 30a via a contact hole 12b penetrating through the interlayer insulating film 12 and the gate insulating layer 30b. The relay electrode 7a is electrically connected to the drain electrode 6b via a contact hole 13a penetrating through the interlayer insulating film 13. The interlayer insulating film 14 has a flat surface, and the pixel electrode 9a is formed on the surface side of the interlayer insulating film 14 (on the side of the liquid crystal layer 80). The pixel electrode 9a is electrically connected to the relay electrode 7a via a contact hole 14a penetrating the interlayer insulating film 14. Therefore, the pixel electrode 9a is electrically connected to the drain region of the pixel switching element 30 via the relay electrode 7a and the drain electrode 6b.

(Structure of the first alignment film 16 and the second alignment film 26)
FIG. 4 is an explanatory diagram schematically showing an enlarged view of the first alignment film 16 and the second alignment film 26 of the liquid crystal device 100 shown in FIG. FIG. 5 is an explanatory diagram schematically showing an enlarged cross section of the first columnar structure 51 shown in FIG. FIG. 6 is an electron micrograph showing an enlarged surface of the first columnar structure 51 shown in FIG. FIG. 7 is an electron micrograph showing an enlarged surface of the second columnar structure 52 shown in FIG. FIG. 8 is an electron micrograph showing an enlarged cross section of the second columnar structure 52 shown in FIG. In FIG. 8, P is given in the direction normal to the substrate, and P0 is given in the major axis direction of the column.

  As shown in FIG. 4, the first alignment film 16 has a multilayer structure. In the present embodiment, the first alignment film 16 is composed of a first inorganic film 161 and a liquid crystal layer with respect to the first inorganic film 161. It has a three-layer structure including a second inorganic film 162 stacked on the 80 side and a third inorganic film 163 stacked on the liquid crystal layer 80 side with respect to the second inorganic film 162. Therefore, the outermost surface of the first alignment film 16 is formed of the third inorganic film 163. The second alignment film 26 also has the same multilayer structure as the first alignment film 16, and in the present embodiment, the second alignment film 26 is different from the first inorganic film 261 and the first inorganic film 261. It has a three-layer structure including a second inorganic film 262 stacked on the liquid crystal layer 80 side and a third inorganic film 263 stacked on the liquid crystal layer 80 side with respect to the second inorganic film 262. Therefore, the outermost surface of the second alignment film 26 is formed of the third inorganic film 263.

Here, the first inorganic films 161 and 261, the second inorganic films 162 and 262, and the third inorganic films 163 and 263 are respectively a vacuum deposition method, an ion plating method, a plasma assist method, an ion assist deposition method, and a molecular beam. It consists of an inorganic film formed by an evaporation method such as an evaporation method. In the present embodiment, each of the first inorganic films 161 and 261, the second inorganic films 162 and 262, and the third inorganic films 163 and 263 is made of silicon oxide (SiO _x ).

  Each of the first inorganic films 161 and 261 includes a first columnar structure 51 having a plurality of first columns 510 deposited by a normal vacuum deposition method without using an ion beam, such as electron beam evaporation or resistance heating evaporation. In this embodiment, each of the first inorganic films 161 and 261 is composed of the first columnar structure 51 having a plurality of first columns 510 deposited by a normal vacuum deposition method without using an ion beam. The first columnar structure 51 has a structure in which the first column 510 is oriented in the normal direction P to one surface 10s of the first substrate 10 (the thickness direction of the liquid crystal layer 80), or in the normal direction P to one surface 10s. It has a structure inclined obliquely to it.

  Each of the second inorganic films 162 and 262 includes a second columnar structure 52 having a plurality of second columns 520 deposited by an ion-assisted deposition method. In the present embodiment, each of the second inorganic films 162 and 262 is formed of the second columnar structure 52 having a plurality of second columns 520 deposited by an ion-assisted deposition method. The second columnar structure 52 has a structure in which the second column 520 is oriented in the normal direction P to the one surface 10s, or has a structure obliquely inclined with respect to the normal direction P to the one surface 10s.

  Like the first inorganic films 161 and 261, the third inorganic films 163 and 263 each include a plurality of third columns 530 deposited by a normal vacuum deposition method that does not use an ion beam, such as electron beam evaporation or resistance heating evaporation. And a third columnar structure 53 provided. In the present embodiment, each of the third inorganic films 163 and 263 has a plurality of third columns 530 having a plurality of third columns 530 deposited by a normal vacuum deposition method without using an ion beam, similarly to the first inorganic films 161 and 261. It consists of a columnar structure 53. The third columnar structure 53 has a structure in which the third column 530 faces the normal direction P to the one surface 10s, or a structure in which the third column 530 is inclined obliquely to the normal direction P to the one surface 10s.

  The thickness of the first inorganic films 161 and 261 is, for example, 10 nm to 30 nm, the thickness of the second inorganic films 162 and 262 is, for example, 20 nm to 70 nm, and the thickness of the third inorganic films 163 and 263 is For example, it is 10 nm to 30 nm.

  Here, the thickness of the second inorganic films 162 and 262 is preferably larger than the thickness of the first inorganic films 161 and 261 and the thickness of the third inorganic films 163 and 263. The thickness of the second inorganic films 162 and 262 is the sum of the thickness of the first inorganic films 161 and 261, the thickness of the second inorganic films 162 and 262, and the thickness of the third inorganic films 163 and 263. It is preferably at least 1/2. According to this aspect, the effect of providing the second inorganic films 162 and 262 is remarkable.

  As described above, in the present embodiment, the first columnar structure 51 and the third columnar structure 53 are formed by a normal vacuum deposition method without using an ion beam, and the second columnar structure 52 is formed by ion-assisted deposition. It is formed by a method. In the ordinary vacuum deposition method, since the energy of the deposition molecules is small, it is difficult to obtain the densification by rearrangement only on the substrate by the deposition. In contrast, in the ion-assisted vapor deposition method, an ion gun is provided in a chamber of a film forming apparatus, and ions are irradiated from the ion gun during film formation to accelerate a material that is slowly floating as molecules. And hit the substrate (the first substrate 10 and the second substrate 20). For this reason, even if the heating temperature of the substrate is low, the adhesion can be secured, and the density of the molecules constituting the film can be further reduced. Therefore, according to the ion-assisted vapor deposition method, the film surface can be homogenized and dense in the thickness direction. In the ion-assisted vapor deposition method, the vapor deposition formed by variously changing the vapor deposition conditions such as the starting pressure during vapor deposition, the pressure during vapor deposition, the acceleration voltage, the acceleration current, the flow rate of the assist gas (ionized gas), and the mixing ratio. The shape and physical properties of the film can be controlled.

  In FIG. 4, in the first alignment film 16 and the second alignment film 26, at least the third column 530 constituting the third columnar structure 53 located on the liquid crystal layer 80 side is arranged in the normal direction P to the one surface 10 s. FIG. Therefore, the first alignment film 16 and the second alignment film 26 form the liquid crystal molecules 80a made of nematic liquid crystal having negative dielectric anisotropy used for the liquid crystal layer 80 by using the one surface 10s of the first substrate 10 and the second alignment film 80a. The liquid crystal molecules 80a are oriented in a state of being inclined with respect to one surface 10s of the substrate 20, and a pretilt is given to the liquid crystal molecules 80a. Thus, the liquid crystal device 100 is configured as a normally black VA mode liquid crystal device. Further, in FIG. 4, in each of the first columnar structure 51, the second columnar structure 52, and the third columnar structure 53, the first column 510, the second column 520, and the third column 530 are one. An example is shown in which the slant is inclined with respect to the normal direction P to the direction 10s.

In the first alignment film 16 and the second alignment film 26 configured as described above, the configuration of the first columnar structure 51 is as shown in FIGS. 5 and 6. There is a large gap between each of the 510s. Therefore, the density of the first columnar structure 51 is 2.1 g / cm ³ or less. Further, the tip of the first column 510 (the end on the liquid crystal layer 80 side) is square. As shown in FIG. 6, a large defect 511 exists in the first columnar structure 51.

Further, the configuration of the third columnar structure 53 is also as shown in FIGS. 5 and 6, and when viewed from the liquid crystal layer 80 side, a large gap is provided between each of the third columns 530. Therefore, the density of the third columnar structure 53 is 2.1 g / cm ³ or less. The tip of the third column 530 (the end on the liquid crystal layer 80 side) is square. However, since the third columnar structure 53 is formed above the second columnar structure 52, there is no large defect 511 as shown in FIG.

The configuration of the second columnar structure 52 is as shown in FIGS. 5, 7 and 8, and when viewed from the liquid crystal layer 80 side, there is only a narrow gap between the second columns 520. For example, in the second columnar structure 52, the ratio occupied by the gap between the second columns 520 is less than 3%, and if such a condition is satisfied, the density of the second inorganic films 162, 262 (second columnar structure 52) Can be made sufficiently high, and the surface area of the second columnar structure 52 in a unit volume can be made sufficiently small. The average thickness of the second column 520 in the second columnar structure 52 is the average thickness of the first column 510 of the first columnar structure 51 and the average thickness of the third column 530 of the third columnar structure 53. Thicker than it is. Accordingly, the density of the second columnar structure 52 is a value exceeding 2.1 g / cm ³ , and the density of the second columnar structure 52 is the density of the first columnar structure 51 and the third columnar structure 53. Higher than the density of

  Further, the tip of the second column 520 (the end on the liquid crystal layer 80 side) has a convex curved surface. Therefore, the surface area of the second columnar structure 52 in the unit volume is smaller than the surface area of the first columnar structure 51 in the unit volume and the surface area of the third columnar structure 53 in the unit volume. Further, the second columnar structure 52 has a smaller surface roughness in a unit volume than the first columnar structure 51 and the third columnar structure 53. Further, the grain size of the second columnar structure 52 is 5 nm to 70 nm. In the second columnar structure 52, since the first columnar structure 51 is formed as a base, a defect as shown in FIG. 6 hardly occurs.

(Production method)
In the manufacturing process of the liquid crystal device 100 according to the present embodiment, the step of forming the first alignment film 16 includes a first film forming step of forming the first inorganic film 161 by a normal vacuum deposition method without using ion assist. A second film forming step of laminating the second inorganic film 162 on the first inorganic film 161 by ion-assisted vapor deposition, and a third film forming process on the second inorganic film 162 by ordinary vacuum vapor deposition without ion assist. And a third film forming step of stacking the inorganic film 163 is performed. In the step of forming the second alignment film 26, a first film forming step of forming the first inorganic film 261 by a normal vacuum deposition method without using ion assist, A second film forming step of laminating the inorganic film 262 by ion-assisted vapor deposition, and a third film forming step of laminating the third inorganic film 263 on the second inorganic film 262 by ordinary vacuum vapor deposition without using ion assist And do. After forming the first alignment film 16 and the second alignment film 26, a heat treatment may be performed at a temperature of about 200 ° C.

(Main effects of this embodiment)
As described above, in the liquid crystal device 100 according to the present embodiment, the first alignment film 16 includes the first inorganic film 161 including the first columnar structure 51 formed by a normal vacuum deposition method and the ion-assisted deposition. A second inorganic film 162 formed of a second columnar structure 52 formed by a conventional method, and a third inorganic film 163 formed of a third columnar structure 53 formed by a normal vacuum deposition method. The outermost surface of the one alignment film 16 is formed of the third columnar structure 53. The second alignment film 26 includes a first inorganic film 261 formed of a first columnar structure 51 formed by a normal vacuum deposition method and a second inorganic film 261 formed of a second columnar structure 52 formed by an ion-assisted deposition method. 2 has an inorganic film 262 and a third inorganic film 263 composed of a third columnar structure 53 formed by a normal vacuum deposition method, and the outermost surface of the first alignment film 16 has a third columnar structure. It consists of 53.

  Here, the density of the second columnar structure 52 is higher than the density of the first columnar structure 51 and the density of the third columnar structure 53, and the tip of the second column 520 (the end on the liquid crystal layer 80 side). Has a convex curved surface. Therefore, the surface area of the second columnar structure 52 in the unit volume is smaller than the surface area of the first columnar structure 51 in the unit volume and the surface area of the third columnar structure 53 in the unit volume. Therefore, even when the outermost surface of the first alignment film 16 and the outermost surface of the second alignment film 26 are made of the third columnar structure 53, the contact area between the first alignment film 16 and the liquid crystal layer 80 and the second The contact area between the alignment film 26 and the liquid crystal layer 80 is small. Therefore, a photochemical reaction between the silanol groups on the surfaces of the first alignment film 16 and the second alignment film 26 and the liquid crystal layer 80 hardly occurs. Therefore, the reliability of the liquid crystal device 100 can be improved.

  Further, in the first alignment film 16 and the second alignment film 26, the first columnar structure 51 is provided on the side opposite to the liquid crystal layer 80 with respect to the second columnar structure 52. 51 functions as a base of the second columnar structure 52. Therefore, film defects are less likely to occur in the second columnar structure 52. Therefore, the first alignment film 16 and the second alignment film 26 are formed with symmetry. Therefore, a potential shift at the time of performing the polarity inversion drive can be reduced, so that occurrence of flicker or the like can be suppressed. Although the second columnar structure 52 has a small surface roughness, since the outermost surface of the first alignment film 16 and the outermost surface of the second alignment film 26 are formed of the third columnar structure 53, the surface roughness is moderate. Big. In addition, since the third columnar structure 53 is based on the second columnar structure 52, the unevenness is uniform. Therefore, the liquid crystal molecules 80 can be properly aligned.

  The second columnar structure 52 is active, but since the outermost surface of the first alignment film 16 and the outermost surface of the second alignment film 26 are formed of the third columnar structure 53, the uppermost surface of the first alignment film 16 is formed. The surface and the outermost surface of the second alignment film 26 have low activity. Therefore, since an increase in ion density can be suppressed, leakage of electric charge or the like when driving the liquid crystal layer 80 is likely to occur.

  Therefore, according to this embodiment, the photochemical reaction with the liquid crystal material when the ion-assisted deposition film (the second columnar structure 52) is used as the alignment film (the first alignment film 16 and the second alignment film 26) is reduced. The defect of the ion-assisted vapor deposition film (the second columnar structure 52) can be covered while taking advantage of the fact that it hardly occurs.

(Evaluation results)
Next, results of evaluating characteristics and the like of the liquid crystal device 100 when the configuration of the alignment film (the first alignment film 16 and the second alignment film 26) is changed will be described. Since the first alignment film 16 and the second alignment film 26 have the same configuration, in the following description, they will be described simply as “alignment films”.

In the following description, conditions for forming the first columnar structure 51 and the third columnar structure 53 by a normal vacuum deposition method, and forming the second columnar structure 52 by an ion-assisted vacuum deposition method. The conditions are as follows. In the conditions described below, the “deposition angle” is an angle formed by a direction normal to the substrate and a direction in which deposition is performed. Note that the following film forming conditions are merely examples, and in carrying out the present invention, the vapor deposition starting pressure, the presence or absence of heat treatment, and the like are not limited to the following conditions.
Conditions for normal vacuum deposition (film formation conditions for first columnar structure 51 and third columnar structure 53)
Electron beam evaporation Deposition source: SiO ₂
Deposition start pressure: 5.0E-4Pa
Deposition angle: 45 °
Deposition temperature: 200 ° C
Film thickness: 20 nm
Conditions for ion-assisted deposition (film formation conditions for second columnar structure 52)
Evaporation source: SiO ₂
Assist gas: O ₂
Neutralizer gas: Ar
Ion acceleration voltage: 1000V
Ion acceleration current: 1000 mA
Neutralizer current: 1500 mA
Deposition start pressure: 5.0E-4Pa
Deposition pressure: 1.0E-2Pa
Deposition angle: 45 °
Deposition temperature: 200 ° C
Deposition thickness: 50 nm
Heat treatment temperature: 200 ° C

(Evaluation 1)
Under the above conditions, a first columnar structure 51 made of a silicon oxide film with a thickness of 20 nm, a second columnar structure 52 made of a silicon oxide film with a thickness of 50 nm, and a second columnar structure 52 made of a silicon oxide film with a thickness of 20 nm. Table 1 shows the measurement results when the three columnar structures 53 were formed. The deposition angle when forming the first columnar structure 51 and the third columnar structure 53 is 45 °, and the deposition angle when forming the second columnar structure 52 is 45 °.

As can be seen from Table 1, the film density of the first columnar structure 51 and the third columnar structure 53, the ratio occupied by the gap region, and the surface roughness Ra in a unit plane area (1 μm × 1 μm) are each 1 9.9 g / cm ³ , 3.6%, 4.3 nm. On the other hand, the film density of the second columnar structure 52, the ratio occupied by the gap region, and the surface roughness Ra in a unit plane area (1 μm × 1 μm) are 2.3 g / cm ³ and 0.8%, respectively. , 1.1 nm. That is, the second columnar structure 52 has a higher film density than the first columnar structure 51 and the third columnar structure 53, a lower proportion of the gap region, and a smaller surface roughness Ra.

  Next, in Table 2, the electrical characteristics and reliability when the liquid crystal device 100 was manufactured using the alignment films according to Reference Example 1, Reference Example 2, and Example 1 were evaluated. Table 2 shows the results. In Table 2, "x" is given to those with poor evaluation results, "◎" is given to the best ones, "○" is given to the next best ones, and intermediate ones between good and bad are given. "△" is attached. The evaluation criteria shown in Table 2 and the like are the criteria set for the main evaluation, and the evaluation results are relative evaluations.

  Reference Example 1 is the second columnar structure 52 having a thickness of 70 nm alone. Reference Example 2 has a laminated structure of a first columnar structure 51 having a thickness of 20 nm and a second columnar structure 52 having a thickness of 60 nm. Example 1 has a stacked structure of a first columnar structure 51 having a thickness of 20 nm, a second columnar structure 52 having a thickness of 50 nm, and a third columnar structure 53 having a thickness of 20 nm.

  It should be noted that the ion density (Ion Density) and the holding ratio (Voltage Holding Ratio) listed as the electrical characteristics are items for evaluating the cause of display failure, and a triangular wave is applied to the liquid crystal device 100, and the current response waveform is measured. Measure. When a reverse polarization current is generated in the liquid crystal device 100, the spontaneous polarization (ion density) of the sample can be measured by integrating the peak of the waveform of the reverse polarization current. The holding ratio (voltage holding ratio) is a holding ratio in one frame of charges charged in a holding capacitor in an active matrix circuit in which pixels in which a liquid crystal capacitor and a holding capacitor are connected in parallel to a pixel switching element are arranged in a matrix. It is. When the voltage holding ratio decreases, a predetermined voltage is not applied to the liquid crystal layer 80, which causes an increase in driving voltage, an increase in power consumption, a decrease in contrast, a decrease in reliability, a generation of display unevenness, and a discoloration. The reliability was measured by measuring a decrease in luminance when a short-wavelength light (blue light) was irradiated for a long time.

  As can be seen from Table 2, in Comparative Example 1 in which the second columnar structure 52 alone was used, there was a problem in ion density and retention, and Comparative Example in which the first columnar structure 51 and the second columnar structure 52 were stacked. In 2, the ion density and the retention are improved, but not enough. On the other hand, in Example 1 in which the first columnar structure 51, the second columnar structure 52, and the third columnar structure 53 were stacked, the ion density and the retention were good.

(Evaluation 2)
Next, as shown in Table 3, blue light was applied to Examples 4 and 5 in which the thickness of the columnar structure was changed in addition to Reference Example 1, Reference Example 2, and Example 3 used in Evaluation 1. The decrease in luminance with respect to the initial luminance when the liquid crystal device 100 was driven under irradiation conditions was evaluated. In this evaluation, the deposition angle when forming the first columnar structure 51 and the third columnar structure 53 was 45 °, and the deposition angle when forming the second columnar structure 52 was 45 °. is there.

  Example 2 has a stacked structure of a first columnar structure 51 having a thickness of 30 nm, a second columnar structure 52 having a thickness of 40 nm, and a third columnar structure 53 having a thickness of 30 nm. Example 3 is a laminated structure of a first columnar structure 51 having a thickness of 40 nm, a second columnar structure 52 having a thickness of 20 nm, and a third columnar structure 53 having a thickness of 40 nm.

  As can be seen from Table 3, Examples 1, 2, and 3 exhibited relatively good reliability. However, as can be seen from the result of comparison between Examples 1 and 2 and Example 3, the film thickness of the second columnar structure 52 is different from the film thickness of the first columnar structure 51 and the film thickness of the third columnar structure 53. It is preferable that the thickness is larger than the film thickness. Further, as can be seen from the result of comparing Example 1 with Examples 2 and 3, the film thickness of the second columnar structure 52 is the film thickness of the first columnar structure 51 and the film thickness of the second columnar structure 52. It is preferable that the thickness is equal to or more than 総 of the total thickness of the third columnar structures 53.

(Evaluation 3)
The angle (column angle) formed by the axial direction of the first column 510 with respect to the normal direction of the substrate is changed from 0 ° to 80 by changing the deposition angle when depositing the first columnar structure 51 with respect to the first embodiment. Table 4 shows the results of evaluating the film density, electrical characteristics (ion density and retention), and reliability of the first columnar structure 51 when the angle was changed to °. In this evaluation, the deposition angle when forming the second columnar structure 52 was 45 °, and the deposition angle when forming the third columnar structure 53 was 0 °.

  As can be seen from the results of Examples 4, 5, and 6 shown in Table 4, good results were obtained when the column angle of the first column 510 was 40 ° or less. From the results of other evaluations, it is preferable that the column angle of the first column 510 is 45 ° or less.

(Evaluation 4)
The angle (column angle) formed by the axis direction of the third column 530 with respect to the normal direction of the substrate is changed from 0 ° to 80 by changing the deposition angle when depositing the third columnar structure 53 with respect to the first embodiment. Table 5 shows the results of evaluating the film density, the electrical characteristics (ion density and retention), and the reliability of the third columnar structure 53 when the angle was changed to °. In this evaluation, the deposition angle when forming the second columnar structure 52 is 45 °, and the deposition angle when forming the first columnar structure 51 is 0 °.

  As can be seen from the results of Examples 9, 10 and 11 shown in Table 5, good results were obtained when the column angle of the third column 530 was 40 ° or less. From the results of other evaluations, it is preferable that the column angle of the third column 530 is 45 ° or less. If the deposition angle when depositing the third columnar structure 53 is too large, the second column 520 of the second columnar structure 52 is shadowed and a defect is easily generated in the third columnar structure 53. It is preferable that the column angle of the third column 530 is 45 ° or less.

(Evaluation 5)
In the above example, the number of stacked alignment films was three. However, Table 6 shows the results of evaluation of electrical characteristics (ion density and retention) and reliability when the number of stacked layers was changed. Table 6 shows each condition in terms of film density. A film density of 1.9 g / cm ³ indicates the third columnar structure 53 having a column angle of 40 °, and a film density of 2.3 g / cm ^3. Shows a second columnar structure 52 having a deposition angle of 45 °, and a film density of 2.1 g / cm ³ indicates a first columnar structure 51 having a column angle of 0 °.

  As can be seen from the results of Examples 12, 13, 14, and 15 shown in Table 6, the number of layers of the first columnar structure 51, the second columnar structure 52, and the third columnar structure 53 is not limited to three layers. As long as columnar structures having different film qualities are alternately arranged, three or more layers such as five layers, seven layers, and nine layers may be used.

[Other embodiments]
In the above embodiment, the third columnar structure 53 is configured to be in direct contact with the liquid crystal layer 80. However, a mode in which a silane coupling process is performed on the surface of the third columnar structure 53 and the organic silane compound layer is stacked. It may be. According to this aspect, since the organic silane compound layer is bonded to the hydroxyl group (-OH) portion by the silane coupling agent, the photochemical reaction between the silanol group on the surface of the inorganic alignment film and the liquid crystal layer 80 is effectively suppressed. Can be.

  The liquid crystal device 100 to which the present invention is applied is not limited to a VA mode liquid crystal device. For example, the present invention may be applied to a case where the liquid crystal device 100 is a TN (Twisted Nematic) mode or OCB (Optically Compensated Bend) mode liquid crystal device.

  The present invention is not limited to the transmission type liquid crystal device 100 but may be applied to a reflection type liquid crystal device.

[Example of mounting on electronic equipment]
An electronic device using the liquid crystal device 100 according to the above-described embodiment will be described. Here, a projection display device (liquid crystal projector) will be described as an example of the electronic apparatus according to the invention. FIG. 9 is an explanatory diagram of a projection display device (electronic device) using the liquid crystal device 100 to which the invention is applied. In FIG. 9, illustration of polarizing plates and the like disposed on the incident side and the exit side of the liquid crystal device 100 is omitted.

  In the projection type display device 2100 shown in FIG. 9, the above-mentioned transmission type liquid crystal device 100 is used as a light valve. The projection display device 2100 is provided with a lamp unit 2102 (light source unit) having a white light source such as a halogen lamp. The projection light emitted from the lamp unit 2102 is converted into three primary colors of R (red), G (green), and B (blue) by three mirrors 2106 and two dichroic mirrors 2108 disposed inside. Separated. The separated projection light is guided to light valves 100R, 100G and 100B corresponding to the respective primary colors. Since the light of B color has a longer optical path than other R and G colors, it is guided through a relay lens system 2121 having an entrance lens 2122, a relay lens 2123, and an exit lens 2124 to prevent the loss. I will

  In the projection display device 2100, three sets of liquid crystal devices including the liquid crystal device 100 are provided corresponding to each of the R, G, and B colors. The configuration of the light valves 100R, 100G, and 100B is the same as that of the above-described transmissive liquid crystal device 100. Light modulated by the light valves 100R, 100G, and 100B is incident on the dichroic prism 2112 from three directions. In the dichroic prism 2112, the R and B lights are reflected at 90 degrees, and the G light is transmitted. Therefore, after the images of the primary colors are combined, a color image is projected on the screen 2120 by the projection lens group 2114 (projection optical system).

(Other projection display devices)
Note that the projection display device may be configured such that an LED light source or the like that emits light of each color is used as a light source unit, and the color light emitted from the LED light source is supplied to another liquid crystal device. .

(Other electronic devices)
The electronic device including the liquid crystal device 100 to which the invention is applied is not limited to the projection display device 2100 of the above embodiment. For example, the present invention may be applied to electronic devices such as a projection-type HUD (head-up display), a direct-view-type HMD (head-mounted display), a personal computer, a digital still camera, and a liquid crystal television.

9a: pixel electrode, 10: first substrate, 10a: display area, 16: first alignment film, 20: second substrate, 21: common electrode, 26: second alignment film, 30: pixel switching element, 50: liquid crystal Layer, 51: first columnar structure, 52: second columnar structure, 53: second columnar structure, 510: first column, 520: second column, 530: third column, 100: liquid crystal device, 100B , 100G, 100R: light valve, 2100: projection display device, 2102: lamp unit (light source unit), 2114: projection lens group (projection lens system).

Claims (9)

  A first inorganic film, a second inorganic film that is stacked on the liquid crystal layer side of the first inorganic film and has a higher density than the first inorganic film, and a second inorganic film that is stacked on the liquid crystal layer side of the second inorganic film; A liquid crystal device comprising an alignment film having a third inorganic film having a lower density than the inorganic film. The liquid crystal device according to claim 1,
The first inorganic film is a first columnar structure including a plurality of first columns,
The second inorganic film is a second columnar structure including a plurality of second columns,
The third inorganic film is a second columnar structure including a plurality of third columns,
A liquid crystal device, wherein at least a part of the plurality of second columns has a convex curved surface at an end on the third inorganic film side. The liquid crystal device according to claim 2,
The liquid crystal device according to claim 1, wherein the average thickness of the plurality of second columns is larger than the average thickness of the plurality of first columns and the average thickness of the plurality of third columns. The liquid crystal device according to claim 2, wherein
At least the plurality of second columns and the plurality of third columns are each inclined obliquely with respect to the thickness direction of the liquid crystal layer. The liquid crystal device according to any one of claims 1 to 4,
The liquid crystal device according to claim 1, wherein a thickness of the second inorganic film is larger than a thickness of the first inorganic film and a thickness of the third inorganic film. The liquid crystal device according to claim 5,
The thickness of the second inorganic film is at least １ ／ of the sum of the thickness of the first inorganic film, the thickness of the second inorganic film, and the thickness of the third inorganic film. Liquid crystal device. The liquid crystal device according to any one of claims 1 to 6,
A first substrate, and a second substrate facing the first substrate via the liquid crystal layer,
A liquid crystal device, wherein the alignment film is provided on both a surface of the first substrate on the liquid crystal layer side and a surface of the second substrate on the liquid crystal layer side.   In the step of forming an alignment film, a first film forming step of forming a first inorganic film by a vacuum deposition method without using ion assist, and a second inorganic film is formed on the first inorganic film by an ion assisted deposition method. A liquid crystal device comprising: a second film forming step of laminating; and a third film forming step of laminating a third inorganic film on the second inorganic film by a vacuum deposition method without using ion assist. Production method.   An electronic apparatus comprising the liquid crystal device according to claim 1.