JP4631334B2 - Liquid crystal devices and electronic devices - Google Patents

Description

  The present invention relates to a liquid crystal device and an electronic apparatus.

  In a light modulation means mounted on a projection display device such as a liquid crystal projector or a liquid crystal device used as a direct view display device mounted on a mobile phone or the like, on the liquid crystal layer side outermost surface of the substrate sandwiching the liquid crystal layer, An alignment film for controlling the alignment of liquid crystal molecules when no voltage is applied is formed, and display is performed based on a change in the alignment of liquid crystal molecules when no voltage is applied.

Conventionally, as the alignment film as described above, the surface of an organic film made of polyimide or the like rubbed in a predetermined direction with a cloth or the like is widely used because of its excellent liquid crystal alignment ability (liquid crystal alignment control function). Yes. However, for example, in the case of mounting on a projection display device or the like that is irradiated with light having a high light intensity of about ² to 10 (lm / mm ² ), the alignment film is gradually decomposed by light or heat, and the long-term After use, the liquid crystal alignment control function is lowered such that the liquid crystal molecules when no voltage is applied cannot be arranged at a desired pretilt angle, and the display quality may be lowered.

  In order to solve such problems, there has been proposed a liquid crystal device that uses an inorganic alignment film made of an inorganic material such as silicon oxide as the alignment film and aligns liquid crystal molecules by the surface shape effect of the inorganic alignment film. . This inorganic alignment film is formed by an oblique vapor deposition method in which a substrate is fixed at a certain angle, an inorganic material is vapor-deposited from one direction, and columnar structures arranged at a predetermined angle with respect to the substrate are grown. The inorganic alignment film thus formed is superior in light resistance and heat resistance as compared with an organic film made of polyimide or the like, and can improve the durability of the liquid crystal device.

In addition, the alignment film used in the liquid crystal device is not limited to the polyimide alignment film or the silicon oxide alignment film. For example, in Patent Document 1, an aluminum oxide porous film is formed by anodizing the surface of an aluminum film. An alignment film in which the surface of such a porous film is rubbed is disclosed.
Japanese Patent No. 2764997

  However, since the alignment film made of a material such as silicon oxide has a hygroscopic property, moisture may enter the liquid crystal device and cause deterioration of the liquid crystal alignment ability. In particular, when the alignment film is formed of a porous film, the surface area becomes large, so that the influence of hygroscopicity can be significant. Such an inorganic alignment film is superior in light resistance and heat resistance to the polyimide film, but the alignment ability itself is inferior to that of the polyimide film. Furthermore, a reaction may occur between the alignment film and the liquid crystal on the surface of the alignment film. Such a defect can contribute to a decrease in the reliability of the alignment film (occurrence of alignment failure, etc.). For example, when a liquid crystal device is used as a display device, it causes display failure or the like. There is a case.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a liquid crystal device having high alignment performance with respect to liquid crystal molecules, preferably excellent in durability and reliability, and an electronic apparatus including the same. It is said.

In order to solve the above problems, a liquid crystal device of the present invention is a liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates arranged to face each other, on the liquid crystal layer side of at least one substrate, An alignment layer capable of aligning liquid crystal molecules is provided, and the alignment layer has a porous surface, and is capable of aligning the liquid crystal molecules on at least a part of the surface and is hydrophobic. Ri Na comprises a layer, the hydrophobic layer is characterized by comprising formed along the interior cavity of the body portion.

  According to such a liquid crystal device, the alignment of liquid crystal molecules can be regulated along the shape of the holes formed on the surface of the alignment layer, and the alignment performance of the hydrophobic layer formed on at least a part of the surface can be controlled. Can also regulate the alignment of liquid crystal molecules. The hydrophobic layer prevents or suppresses the intrusion of moisture into the alignment layer, and can realize stable alignment regulation regardless of the type of material constituting the alignment layer. Inconveniences such as a reaction between the two and the like hardly occur. In addition, the alignment layer according to the present invention can be formed without using a material such as polyimide that is inferior in light resistance, and it is also necessary to use an oblique deposition method that is difficult to form uniformly, such as an inorganic alignment film. Therefore, it is excellent in light resistance and can be formed in a uniform film thickness within the surface. Therefore, according to the above configuration, it is possible to provide a liquid crystal device including an alignment layer having high alignment performance with respect to liquid crystal molecules and having excellent durability and reliability.

  In order to solve the above-described problem, the liquid crystal device of the present invention is a liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates arranged to face each other, and the liquid crystal layer side of at least one substrate is In addition, an alignment layer capable of aligning liquid crystal molecules is provided. The alignment layer includes a main body having a plurality of pores, and can align the liquid crystal molecules on at least a part of the surface of the main body and is hydrophobic. And a hydrophobic layer having properties.

  According to such a liquid crystal device, the alignment of liquid crystal molecules can be regulated along the shape of the pores of the main body, and the liquid crystal molecules are also aligned by the alignment performance of the hydrophobic layer formed on the surface of the main body. Can be regulated. The hydrophobic layer on the surface of the main body prevents or suppresses the intrusion of moisture into the alignment layer, can realize stable alignment regulation regardless of the material of the main body, and between the liquid crystal molecules and the main body. Problems such as reaction are unlikely to occur. In addition, the alignment layer according to the present invention can be formed without using a material such as polyimide that is inferior in light resistance, and it is also necessary to use an oblique deposition method that is difficult to form uniformly, such as an inorganic alignment film. Therefore, it is excellent in light resistance and can be formed uniformly in the surface. Therefore, according to the configuration of the present invention, it is possible to provide a liquid crystal device including an alignment layer having high alignment performance with respect to liquid crystal molecules and having excellent durability and reliability.

  The hydrophobic layer may be configured to align the liquid crystal molecules in a direction perpendicular to the surface of the hydrophobic layer. Such a hydrophobic layer functions as a vertical alignment film, and can control the alignment of liquid crystal molecules in the vertical direction with respect to the surface of the layer, and the outermost surface of the main body and / or the bottom surface of the pores of the main body. By disposing the hydrophobic layer on the liquid crystal, it becomes possible to further enhance the alignment regulating force of the liquid crystal molecules along the shape of the pores.

  The hydrophobic layer may be formed along the inside of the hole of the main body. In this case, the effect of protecting the main body, that is, the effect of preventing the ingress of moisture or the effect of preventing the liquid crystal and the main body from reacting is further enhanced. The hydrophobic layer is preferably made of a material that is at least more hydrophobic than the main body.

  On the other hand, the holes in the main body can be substantially upright on the substrate along the normal direction of the substrate surface. In this case, the alignment of the liquid crystal molecules can be regulated along the upright direction of the holes, that is, in the direction perpendicular to the substrate. Is suitable.

  Moreover, the internal shape of the void | hole of the said main-body part shall be substantially cylindrical shape. In this case, excellent orientation can be obtained along the cylindrical shape, and a merit in the manufacturing process that pores can be formed relatively easily by using the above shape is also obtained. Further, the holes of the main body may be formed to be inclined with respect to the substrate. In this case, the liquid crystal molecules can be aligned in an inclined state with respect to the substrate. This makes it possible to control the tilt direction of the liquid crystal molecules when a voltage is applied. Therefore, according to these configurations, it is possible to provide a liquid crystal device that is less likely to cause display unevenness and has excellent display quality.

  In the liquid crystal device of the present invention, the opening diameter of the holes can be 5 nm or more and 100 nm or less. If the opening diameter is less than 5 nm, it becomes difficult to form pores, which may lead to a decrease in productivity. On the other hand, when the opening diameter exceeds 100 nm, the orientation of the liquid crystal molecules may be lowered.

  In the liquid crystal device of the present invention, the pitch of the holes can be 5 nm or more and 250 nm or less. If the pitch is less than 5 nm, it becomes difficult to form pores, which may lead to a decrease in productivity. On the other hand, when the pitch exceeds 250 nm, the distance between the holes is too large, and the orientation of the liquid crystal molecules may be lowered.

  In the liquid crystal device of the present invention, the depth of the holes can be 5 nm or more and 200 nm or less. If the depth is less than 5 nm, the alignment regulating force may be reduced and the alignment of the liquid crystal molecules may be deteriorated. On the other hand, if the depth exceeds 200 nm, the average distance between the liquid crystal layer and the electrode layer becomes large, which may increase the driving voltage.

  In the liquid crystal device of the present invention, the pore density (pitch / aperture diameter) can be 1 or more and 2.5 or less. When the density of the holes is less than 1, the holes overlap each other and the substantial opening diameter of the holes becomes large, so that the orientation may be lowered. On the other hand, when the density exceeds 2.5, the distance between the holes becomes large and the orientation may be lowered.

  In the liquid crystal device of the present invention, the aspect ratio (depth / opening diameter) of the holes can be 1 or more and 40 or less. When the aspect ratio of the holes is less than 1, the liquid crystal orientation may be lowered. If holes having an aspect ratio exceeding 40 are formed, the average distance between the electrode layer and the liquid crystal layer may be large, and the drive voltage may be high.

  Furthermore, the liquid crystal device of the present invention has a configuration in which at least liquid crystal molecules arranged adjacent to the substrate among the liquid crystal molecules constituting the liquid crystal layer are aligned substantially perpendicularly to the substrate. Is preferred. The liquid crystal layer is preferably composed of a liquid crystal having negative dielectric anisotropy. The alignment layer according to the present invention is particularly suitable for a vertical alignment mode liquid crystal device.

  Moreover, it is preferable that the liquid crystal device of the present invention has a configuration in which the pores are filled with liquid crystal. With such a configuration, the alignment regulating force due to the holes effectively acts on the liquid crystal molecules. Further, since the distance between the electrode layer and the liquid crystal layer is reduced, the liquid crystal layer can be driven more smoothly by applying a voltage.

  Next, an electronic apparatus according to the present invention includes the liquid crystal device according to the present invention. According to such a configuration, liquid crystal molecules that can reliably regulate the alignment of liquid crystal molecules, are less prone to display defects due to the mixing of moisture and the like, and can have a low driving voltage and have excellent reliability and power consumption. An electronic apparatus provided with the apparatus as a light modulation unit or an image display unit can be provided.

As such an electronic apparatus, the liquid crystal device is provided as light modulation means, and a projection display device provided as projection means for projecting the light modulated by the light modulation means, or the liquid crystal device is a direct-view type display unit. Examples of such devices can be given.
In other words, “electronic devices” are not limited, but for example, television receivers, car navigation devices, POS, personal computers, head-mounted displays, rear-type or front-type projectors, fax machines with display functions, electronic guide boards, transportation Information panels for vehicles, game devices, machine tool operation panels, electronic books, digital cameras, portable TVs, DSP devices, PDAs, electronic notebooks, mobile phones, mobile devices such as video cameras, etc. Needless to say.

  Embodiments of the present invention will be described below with reference to the drawings. In each drawing used for the following description, the scale of each member is appropriately changed to make each member a recognizable size.

(Liquid crystal device)
The liquid crystal device of the present embodiment described below is an active matrix vertical alignment mode transmission type liquid crystal device using a TFT (thin film transistor) element as a switching element and using a liquid crystal having negative dielectric anisotropy. The liquid crystal device of this embodiment is characterized by the configuration of an alignment film (alignment layer) provided in contact with the liquid crystal layer.

  FIG. 1 is an equivalent circuit diagram of switching elements, signal lines, and the like in a plurality of pixels arranged in a matrix that constitutes an image display region of the transmissive liquid crystal device of this embodiment. FIG. 2 is a plan view showing the structure of a plurality of pixel groups adjacent to each other on a TFT array substrate on which data lines, scanning lines, pixel electrodes and the like are formed. FIG. 3 is a cross-sectional view showing the structure of the transmissive liquid crystal device of this embodiment, and is a cross-sectional view taken along the line A-A ′ of FIG. 2. FIG. 4 is an enlarged plan view and cross-sectional view showing an alignment film provided in the transmissive liquid crystal device of this embodiment. In addition, in each figure, in order to make each layer and each member the size which can be recognized on drawing, the scale is varied for every layer and each member.

  In the transmissive liquid crystal device according to the present embodiment, as shown in FIG. 1, a plurality of pixels arranged in a matrix that constitutes an image display region are subjected to energization control for the pixel electrode 9 and the pixel electrode 9. TFT elements 30 as switching elements are formed, and a data line 6 a for supplying an image signal is electrically connected to the source of the TFT element 30. Image signals S1, S2,..., Sn to be written to the data line 6a are supplied line-sequentially in this order, or are supplied for each group to a plurality of adjacent data lines 6a.

  In addition, the scanning line 3a is electrically connected to the gate of the TFT element 30, and scanning signals G1, G2,..., Gm are applied to the plurality of scanning lines 3a in a pulse-sequential manner at predetermined timing. The Further, the pixel electrode 9 is electrically connected to the drain of the TFT element 30, and the image signal S1, S2,... Supplied from the data line 6a is turned on by turning on the TFT element 30 as a switching element for a certain period. , Sn is written at a predetermined timing.

  Image signals S1, S2,..., Sn written to the liquid crystal via the pixel electrode 9 are held for a certain period with the common electrode 21 (see FIG. 3) described later. The liquid crystal changes the orientation and order of the molecular assembly depending on the applied voltage level, and modulates the light transmitted through the liquid crystal layer based on the change to enable gradation display. Here, in order to prevent the held image signal from leaking, a storage capacitor 70 is added in parallel with the liquid crystal capacitor formed between the pixel electrode 9 and the common electrode 21 (see FIG. 3). .

  Next, the pixel structure of the transmissive liquid crystal device of this embodiment will be described with reference to FIG. As shown in FIG. 2, on the TFT array substrate 10 (see FIG. 3), a rectangular pixel electrode 9 (outlined by a dotted line portion 9a) made of a transparent conductive material such as indium tin oxide (ITO) is formed. The data lines 6 a, the scanning lines 3 a, and the capacitor lines 3 b are provided along the vertical and horizontal boundaries of the pixel electrodes 9. In the present embodiment, each pixel electrode 9 and the area where the data line 6a, the scanning line 3a, the capacitor line 3b, etc. are arranged so as to surround each pixel electrode 9 are pixels, and are arranged in a matrix. The display can be displayed for each pixel.

  The data line 6a is electrically connected to a source region (described later) through a contact hole 5 in the semiconductor layer 1a made of, for example, a polysilicon film constituting the TFT element 30, and the pixel electrode 9 is connected to the semiconductor layer 1a. Among these, it is electrically connected to a drain region described later via a contact hole 8. In addition, the scanning line 3a is disposed so as to face a channel region (a region with a diagonal line rising to the left in the figure), which will be described later, of the semiconductor layer 1a. The scanning line 3a serves as a gate electrode at a portion facing the channel region. Function.

  The capacitor line 3b is formed from a main line portion extending in a substantially straight line along the scanning line 3a (that is, a first region formed along the scanning line 3a in a plan view) and a portion intersecting the data line 6a. And a protruding portion (that is, a second region extending along the data line 6 a when viewed in a plan view) protruding toward the previous stage (upward in the drawing) along the data line 6 a. In FIG. 2, a plurality of first light shielding films 11 a are provided in a region indicated by a diagonal line rising to the right.

  Next, a cross-sectional structure of the transmissive liquid crystal device of the present embodiment will be described based on FIG. As shown in FIG. 3, in the transmissive liquid crystal device according to the present embodiment, a vertical alignment mode comprising a liquid crystal having a negative dielectric anisotropy between the TFT array substrate 10 and a counter substrate 20 disposed opposite thereto. The liquid crystal layer 50 is sandwiched. The TFT array substrate 10 is mainly composed of a substrate body 10A made of a translucent material such as quartz, a TFT element 30 formed on the surface of the liquid crystal layer 50, a pixel electrode 9 and an alignment film 40. The counter substrate 20 is mainly composed of a substrate body 20A made of a light-transmitting material such as glass or quartz, a common electrode 21 formed on the surface of the liquid crystal layer 50, and an alignment film 60.

  In the TFT array substrate 10, pixel electrodes 9 are provided on the surface of the substrate body 10 </ b> A on the liquid crystal layer 50 side, and pixel switching TFT elements 30 that perform switching control of the pixel electrodes 9 are provided at positions adjacent to the pixel electrodes 9. It has been. The pixel switching TFT element 30 has an LDD (Lightly Doped Drain) structure, and includes a scanning line 3a, a channel region 1a ′ of the semiconductor layer 1a in which a channel is formed by an electric field from the scanning line 3a, and the scanning line 3a. A gate insulating film 2 that insulates the semiconductor layer 1a, a data line 6a, a low concentration source region 1b and a low concentration drain region 1c of the semiconductor layer 1a, and a high concentration source region 1d and a high concentration drain region 1e of the semiconductor layer 1a. ing.

  Further, a second contact hole 5 leading to the high concentration source region 1d and a contact hole 8 leading to the high concentration drain region 1e are formed on the substrate main body 10A including the scanning line 3a and the gate insulating film 2. An interlayer insulating film 4 is formed. That is, the data line 6 a is electrically connected to the high concentration source region 1 d through the contact hole 5 that penetrates the second interlayer insulating film 4. Further, on the data line 6a and the second interlayer insulating film 4, a third interlayer insulating film 7 having a contact hole 8 leading to the high concentration drain region 1e is formed. That is, the high concentration drain region 1 e is electrically connected to the pixel electrode 9 through the contact hole 8 that penetrates the second interlayer insulating film 4 and the third interlayer insulating film 7.

  In the present embodiment, the gate insulating film 2 is extended from a position facing the scanning line 3a and used as a dielectric film, the semiconductor film 1a is extended to form the first storage capacitor electrode 1f, and further opposed thereto. The storage capacitor 70 is configured by using a part of the capacitor line 3b to be a second storage capacitor electrode.

  Further, on the surface of the TFT array substrate 10 on the liquid crystal layer 50 side of the substrate main body 10A, the region where the pixel switching TFT elements 30 are formed is transmitted through the TFT array substrate 10, and the lower surface (TFT) of the TFT array substrate 10 is illustrated. The light that is reflected at the interface between the array substrate 10 and air) and returned to the liquid crystal layer 50 side is prevented from entering at least the channel region 1a ′ and the low concentration source / drain regions 1b and 1c of the semiconductor layer 1a. For this purpose, a first light shielding film 11a is provided. Further, a first interlayer insulation for electrically insulating the semiconductor layer 1a constituting the pixel switching TFT element 30 from the first light shielding film 11a is provided between the first light shielding film 11a and the pixel switching TFT element 30. A film 12 is formed. Further, as shown in FIG. 2, in addition to providing the first light-shielding film 11a on the TFT array substrate 10, the first light-shielding film 11a is electrically connected to the capacitor line 3b at the preceding stage or the subsequent stage through the contact hole 13. Configured to connect to.

  Further, on the liquid crystal layer 50 side outermost surface of the TFT array substrate 10, that is, on the pixel electrode 9 and the third interlayer insulating film 7, an alignment film (which controls the alignment of liquid crystal molecules in the liquid crystal layer 50 when no voltage is applied). Alignment layer) 40 is formed. The alignment film 40 has a function of aligning liquid crystal molecules in a direction perpendicular to the film surface.

  On the other hand, the counter substrate 20 has a surface on the liquid crystal layer 50 side of the substrate body 20A, which is a region facing the formation region of the data line 6a, the scanning line 3a, and the pixel switching TFT element 30, that is, an opening region of each pixel unit. A second light-shielding film 23 for preventing incident light from entering the channel region 1a ′, the low-concentration source region 1b, and the low-concentration drain region 1c of the semiconductor layer 1a of the pixel switching TFT element 30 in a region other than Is provided. Further, a common electrode 21 made of ITO or the like is formed over the substantially entire surface of the substrate body 20A on which the second light shielding film 23 is formed, and a voltage is applied to the liquid crystal layer 50 side. An alignment film (alignment layer) 60 for controlling the alignment of liquid crystal molecules in the liquid crystal layer 50 when no voltage is applied is formed.

  As described above, in this embodiment, the structures of the alignment films (alignment layers) 40 and 60 are characteristic. Hereinafter, the structure of the alignment film 40 and its operation will be described with reference to FIGS. 4 and 5. 4A is an enlarged partial plan view showing the alignment film 40, and FIG. 4B is a partial cross-sectional view taken along line B-B ′ shown in FIG. FIG. 5 is a partial cross-sectional schematic diagram for explaining the alignment control action of the liquid crystal molecules by the alignment film 40. In the present embodiment, since the alignment film 40 on the TFT array substrate 10 side and the alignment film 60 on the counter substrate 20 side have the same structure, the alignment film 40 will be mainly described below.

  As shown in FIG. 4A, the alignment film 40 according to the present embodiment has a configuration in which holes 40a having a circular shape in plan view are arranged in a lattice pattern at a predetermined pitch p. As shown in FIG. 4B, it is formed so as to penetrate the alignment film 40 substantially vertically. Therefore, the pixel electrode 9 is exposed to the liquid crystal layer 50 in the region where the hole 40a is provided, and the liquid crystal of the liquid crystal layer 50 is filled in the hole 40a.

In the case of this embodiment, as shown in FIG. 5, the alignment film 40 is made of an insulating material such as SiO ₂ , Al ₂ O ₃ (particularly anodized alumina) and has a porous structure having a plurality of holes. 44 and a hydrophobic layer 43 that covers the surface of the porous structure 44 and is made of a material having a higher hydrophobicity than the porous structure 44 (a material having a large contact angle with water). The hydrophobic layer 43 is composed of, for example, a compound containing a long-chain alkyl group (for example, about 5 to 20 carbon atoms, n-decyl group in this embodiment). The hydrophobic layer 43 has a function of regulating the alignment of liquid crystal molecules. Specifically, the hydrophobic layer 43 has a function of vertically aligning liquid crystal molecules along a long-chain alkyl group. Note that the porous structure 44 and the hydrophobic layer 43 are both made of a material having high light transmittance, and the hydrophobic layer 43 is formed at the bottom of the hole 40a so as to cover the surface layer of the pixel electrode 9. .

  The holes 40 a of the alignment film 40 have a substantially cylindrical shape, and are arranged so that the length direction thereof is substantially upright with respect to the surface of the electrode 9. In the present embodiment, the dimensions of the holes 40a and the arrangement thereof shown in FIG. 4 are such that the opening diameter φ on the surface of the alignment film 40 is about 50 nm, the pitch p is about 60 nm, and the depth d is about 120 nm. Therefore, the density of the holes 40a on the surface of the alignment film 40 (pitch p / opening diameter φ) is about 1.2, and the aspect ratio of the holes 40a in the thickness direction of the alignment film 40 (depth d / opening diameter φ). Is about 2.4.

  Then, as shown in FIG. 5, since a plurality of such fine holes 40a are provided through the alignment film 40, the liquid crystal molecules 51 of the liquid crystal layer 50 in contact with the alignment film 40 are formed in the holes 40a. As a result, the liquid crystal molecules 51 in the entire liquid crystal layer 50 are substantially perpendicular to the TFT array substrate 10 and the counter substrate 20 (specifically, normal to the substrate surface). Or 0 ° to 5 ° (for example, about 2.5 °).

  As described above, in the liquid crystal device according to the present embodiment, the alignment film 40 having the plurality of holes 40a is formed on the pixel electrode 9, so that the liquid crystal molecules having good liquid crystal molecules can be formed along the shape of the holes 40a. Orientation regulation is possible. In addition, since the hydrophobic layer 43 that protects the porous structure 44 provided to form the pores 40a is formed, the material selection range of the porous structure 44 is widened. Even when the porous structure 44 is made of a material having high properties, the adsorption of moisture to the structure 44 can be prevented or suppressed. As a result, the reliability of the liquid crystal device of this embodiment is increased. Further, even when the porous structure 44 is composed of a highly reactive material, the hydrophobic layer 43 can prevent or suppress the reaction between the structure 44 and the liquid crystal molecules. Become. Furthermore, in this embodiment, since the hydrophobic layer 43 is formed on the pixel electrode 9, the reaction between the pixel electrode 9 and the liquid crystal molecules is prevented or suppressed.

  The porous structure 44 can be formed, for example, by patterning using a photolithography technique. In the case of using a photolithography technique, an etching method or electron beam irradiation can be used as a method for selectively removing the hole portion of the structure 44. The hydrophobic layer 43 can be formed by a silane coupling process, specifically, n-decyltriethoxysilane is formed by coupling the structure 44 with the structure 44.

  In the present embodiment, the alignment film 40 in which a large number of holes 40a having substantially the same dimensions are arranged at the same pitch in a plan view lattice shape has been described. However, the plurality of holes 40a are not necessarily formed to have the same dimensions. You don't have to. Further, the planar arrangement of the holes 40a is not limited to a lattice shape. That is, the alignment film 40 may be formed with a plurality of holes 40a having different dimensions, and even if the holes 40a are arranged almost randomly on the surface of the alignment film 40, the holes are arranged with a shifted pitch. It does not matter. On the other hand, when the pores 40 are extremely fine or too large, there is a concern that the productivity is lowered or a sufficient alignment regulating force cannot be obtained. Therefore, a preferable range of each dimension of the hole 40a is shown below.

  The opening diameter φ of the holes 40a on the surface of the alignment film 40 is preferably 5 nm to 100 nm. When the opening diameter φ is less than 5 nm, it is difficult to form the air holes 40a, and the productivity may be reduced. When the opening diameter φ exceeds 100 nm, the orientation of the liquid crystal molecules may be lowered. Considering the productivity at the time of forming the holes 40a and the orientation, a more preferable opening diameter φ is 50 nm ± 5 nm.

  Next, the pitch p of the holes 40a is preferably 5 nm to 250 nm. If the pitch p is less than 5 nm, it is difficult to form the holes 40a, and the productivity may be reduced. On the other hand, when the pitch exceeds 250 nm, the distance between the holes 40a is too large, and the orientation of the liquid crystal molecules may be lowered. Considering the productivity at the time of forming the holes 40a and the orientation, a more preferable pitch p is 60 nm ± 6 nm.

  Next, the depth d of the holes 40a is preferably 5 nm to 200 nm. When the depth d is less than 5 nm, the alignment regulating force is reduced, and the alignment of the liquid crystal molecules may be deteriorated. On the other hand, if the depth exceeds 200 nm, the average distance between the liquid crystal layer 50 and the pixel electrode 9 may be large, and the drive voltage may be high. Considering the orientation due to the holes 40a and the increase in driving voltage, the more preferable depth d is 120 nm ± 12 nm.

  In addition to the dimensions of each part of the hole 40a, the aspect ratio (depth d / opening diameter φ) of the hole 40a is preferably 1 to 40, and the planar density (pitch) of the hole 40a is preferably 1-40. p / opening diameter φ) is preferably 1 to 2.5. When the aspect ratio of the holes 40a is less than 1, the liquid crystal orientation may be lowered. Further, when the hole 40a having an aspect ratio exceeding 40 is formed, the average distance between the pixel electrode 9 and the liquid crystal layer 50 is large, and the drive voltage may be increased. A more preferable range of the aspect ratio is about 2.4 ± 0.24 from the range of the opening diameter φ and the depth d. In addition, when the density of the holes 40a is less than 1, the holes 40a overlap each other and the substantial opening diameter of the holes 40a increases, so that the orientation may be lowered. On the other hand, when the density exceeds 2.5, the distance between the holes 40a may increase and the orientation may deteriorate. A more preferable range of the density is about 1.2 ± 0.12 from the range of the opening diameter φ and the pitch p.

  In the present embodiment, the porous structure 44 of the alignment film 40 is made of an insulating material, but it can also be made of a light-transmitting conductive material such as ITO. In this case, the hydrophobic layer 43 prevents a short circuit with the opposite electrode.

Next, modified examples of the alignment film 40 provided in the liquid crystal device of the above embodiment will be described with reference to FIGS.
First, FIG. 6 is a diagram showing a partial cross-sectional configuration of the alignment film (alignment layer) of the first modification, and corresponds to FIG. 4B of the above embodiment. As shown in FIG. 6, in the first modification, the holes 40 a formed through the alignment film 40 are formed to be inclined with respect to the layer thickness direction (the vertical direction in the drawing) of the alignment film 40. . That is, the holes 40 a of the alignment film 40 are formed to be inclined with respect to the surfaces of the substrates 10 and 20. Such an inclined configuration can be obtained, for example, by performing oblique etching (or sputtering) on a solid SiO ₂ film formed on the pixel electrode 9.

  In such an alignment film, the vacancies 40a are formed inclining in the right direction in the figure, so that the liquid crystal molecules 51 of the liquid crystal layer 50 are also incliningly aligned along the length direction of the vacancies 40a. Therefore, according to such a configuration, it is possible to realize a state similar to that in which a pretilt is applied to the liquid crystal molecules 51, and the liquid crystal molecules 51 are tilted toward the tilt direction side of the holes 40a when a voltage is applied. Thereby, it is possible to prevent a plurality of regions (domains) having different tilt directions from being formed in the dot region, and to effectively prevent display unevenness caused by disclination of these region boundaries. it can.

  Next, FIG. 7 is a diagram showing a partial cross-sectional configuration of the alignment film (alignment layer) of the second modified example, and corresponds to FIG. 5 of the above embodiment. In the example shown in FIG. 5, the hydrophobic layer 43 is formed on the entire surface of the porous structure 44. However, in the second modification, only the outermost surface of the porous structure 44, that is, the empty structure, as shown in FIG. 7. A hydrophobic layer 43 is formed only outside the hole 40a. In this case, the effect of preventing moisture from entering the porous structure 44 and the effect of preventing contact with the liquid crystal molecules are reduced, but a decrease in the alignment regulating force from the wall surface of the pores 40a can be suppressed. Will increase.

  Next, FIG. 8 is a diagram showing a partial cross-sectional configuration of the alignment film (alignment layer) of the third modification, and corresponds to FIG. 5 of the above embodiment. In the example shown in FIG. 5, the hydrophobic layer 43 is formed on the entire surface of the porous structure 44. However, in the third modification, the outermost surface of the porous structure 44 and the pores are formed as shown in FIG. The hydrophobic layer 43 is formed on the bottom of the hole 40a, and the hydrophobic layer 43 is not formed on the wall surface of the hole 40a. In this case, compared with the second modified example, the vertical alignment regulating force of the liquid crystal molecules extends from the hole bottom of the hole 40a, so that the vertical alignment ability of the alignment film 40 is higher than that of the second modified example. Become.

(Electronics)
Next, as an embodiment of the electronic apparatus of the present invention, a configuration of a projection display device including the liquid crystal device of the above embodiment as a light modulation unit will be described with reference to the drawings. FIG. 9 is a schematic configuration diagram showing a main part of a projection display device using the liquid crystal device of the above embodiment as a light modulation device. In this figure, 510 is a light source, 513 and 514 are dichroic mirrors, 515, 516 and 517 are reflection mirrors, 518 is an entrance lens, 519 is a relay lens, 520 is an exit lens, 522, 523 and 524 are liquid crystal light modulators, Reference numeral 525 denotes a cross dichroic prism, and 526 denotes a projection lens.

  The light source 510 includes a lamp 511 such as a metal halide and a reflector 512 that reflects the light of the lamp. The blue light and green light reflecting dichroic mirror 513 transmits red light of the light flux from the light source 510 and reflects blue light and green light. The transmitted red light is reflected by the reflection mirror 517 and is incident on the liquid crystal light modulation device 522 for red light including the liquid crystal device of the above embodiment. On the other hand, green light out of the color light reflected by the dichroic mirror 513 is reflected by the dichroic mirror 514 that reflects green light and enters the liquid crystal light modulation device 523 for green light including the liquid crystal device of the above embodiment. Note that the blue light also passes through the second dichroic mirror 514. For blue light, in order to compensate for the difference in optical path length from green light and red light, a light guide means 521 comprising a relay lens system including an incident lens 518, a relay lens 519, and an exit lens 520 is provided. Through this, the blue light is incident on the blue light liquid crystal light modulation device 524 including the liquid crystal device of the above embodiment. Before and after the liquid crystal light modulator for red light 522, the liquid crystal light modulator for green light 523, and the liquid crystal light modulator for blue light 524, incident side polarizing plates 522a, 523a and 524a and outgoing side polarizing plates 522b, 523b and 524b, respectively. Is installed. The light that has been linearly polarized by the incident-side polarizing plate is modulated by the liquid crystal light modulator and then passes through the outgoing-side polarizing plate. However, since only light in the determined vibration direction can be transmitted at this time, dimming is possible. .

  The three color lights modulated by the respective light modulators and the two polarizing plates are incident on the cross dichroic prism 525. In this prism, four right-angle prisms are bonded together, and a dielectric multilayer film that reflects red light and a dielectric multilayer film that reflects blue light are formed in a cross shape on the inner surface. These dielectric multilayer films combine the three color lights to form light representing a color image. The synthesized light is projected onto the screen 527 by the projection lens 526 which is a projection optical system, and the image is enlarged and displayed.

  Since the projection display device having the above-described structure includes the liquid crystal device of the above-described embodiment, the projection display device is excellent in mass productivity, has high alignment regulating power for the liquid crystal molecules constituting the liquid crystal layer, and is durable against light and heat. It is an excellent and highly reliable display device.

  Although the embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. For example, although the above embodiment shows a transmissive liquid crystal device, the structure of the present invention can also be applied to a reflective or transflective liquid crystal device. In this case, examples of the electronic device include a mobile phone provided with a direct-view display unit and a display of a personal computer.

1 is an equivalent circuit diagram of wiring and the like in a liquid crystal device according to an embodiment of the present invention. FIG. 2 is a plan view showing a pixel structure of the liquid crystal device of FIG. 1. Sectional drawing which shows the structure of the principal part about the liquid crystal device of FIG. FIG. 2 is a partial plan view and a partial cross-sectional view of an alignment film provided in the liquid crystal device of FIG. 1. Explanatory drawing which shows the orientation state of the liquid crystal molecule by the orientation film shown in FIG. The fragmentary sectional view which shows the structure of the alignment film of a 1st modification. The fragmentary sectional view which shows the structure of the alignment film of a 2nd modification. The fragmentary sectional view which shows the structure of the alignment film of a 3rd modification. The figure which shows an example about the projection type display apparatus which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 9 ... Pixel electrode (electrode layer), 10 ... TFT array substrate, 20 ... Counter substrate, 21 ... Common electrode (electrode layer), 40, 60 ... Alignment film (alignment layer), 40a ... Hole, 43 ... Hydrophobic layer, 44 ... Porous structure (main body), 50 ... Liquid crystal layer

Claims (8)

A liquid crystal device in which a liquid crystal layer is sandwiched between a pair of substrates disposed to face each other,
An alignment layer capable of aligning liquid crystal molecules is provided on the liquid crystal layer side of at least one substrate,
The alignment layer includes a body portion having a plurality of holes, Ri Na and and a hydrophobic layer formed with a possible and hydrophobic orienting the liquid crystal molecules in at least part of the surface of the body portion,
The liquid crystal device , wherein the hydrophobic layer is formed along the inside of a hole of the main body .   The liquid crystal device according to claim 1, wherein the hydrophobic layer is configured to be capable of aligning the liquid crystal molecules in a direction perpendicular to a surface of the hydrophobic layer. The liquid crystal device according to claim 1 , wherein the hydrophobic layer has higher hydrophobicity than the main body. 4. The liquid crystal device according to claim 1 , wherein the hole of the main body portion is substantially upright on the substrate along a normal direction of the substrate surface. 5. 5. The liquid crystal device according to claim 1, wherein an inner shape of a hole of the main body is a substantially columnar shape. The liquid crystal device according to claim 1 , wherein the holes of the main body are formed to be inclined with respect to the substrate. The liquid crystal device according to claim 1 , wherein the liquid crystal layer is composed of a liquid crystal having negative dielectric anisotropy. An electronic apparatus comprising the liquid crystal device according to claim 1 .

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