JP2005326679A - Electrooptical device, method for manufacturing the same, and electronic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently manufacture an electrooptical device, with which a high-quality display is produced. <P>SOLUTION: In an alignment layer forming step, the alignment layer is formed on a substrate surface of at least one out of a pair of substrates, having stripe shaped elevation changes, by conducting oblique deposition with a prescribed deposition angle along a deposition direction set in the substrate surface taking the extending direction of the elevation changes as a reference and in a range in which no alignment defect of an electro-optic material occurs. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a manufacturing method of an electro-optical device such as a liquid crystal device, and the technical field of the electro-optical device and an electronic apparatus including the electro-optical device such as a liquid crystal projector.

  In this type of electro-optical device, the alignment of the electro-optical material is controlled by an alignment film having a specific surface shape. Such an alignment film is formed by a method of depositing silicon oxide (SiO) or the like obliquely with respect to the substrate (hereinafter referred to as “oblique deposition”), in addition to a case where the alignment film is formed by performing a rubbing treatment after the film formation. May be created.

  However, in most cases, a step is present on the surface of the substrate serving as the base of the alignment film. That is, on the TFT array substrate, data lines, scanning lines, pixel electrodes and the like have a laminated structure on the substrate, and the thickness causes unevenness. On the counter substrate facing the TFT array substrate, a step is similarly generated due to the presence of a light shielding film, a color filter, and the like.

  In that case, during oblique deposition, a region that is difficult to deposit or is not deposited at all is formed behind the step. If such deposition spots are present in the alignment film, the alignment regulating force of the electro-optic material is weakened, which causes a decrease in contrast ratio due to light leakage and a decrease in transmittance.

  In view of this, there has been proposed a method for eliminating deposition spots on the alignment film or display spots caused by the deposition spots. For example, Patent Document 1 proposes a technique of covering a region corresponding to a region that becomes a shadow of a step in oblique deposition of an alignment film with a light shielding film. Patent Document 2 discloses an alignment film composed of two layers of obliquely deposited films. In this case, the second-layer vapor-deposited film is different from the first-layer vapor-deposited film in the azimuth direction along the in-plane direction of the substrate, so that the second-layer vapor-deposited film can be applied to a shadow of a step that is difficult to be vapor-deposited in the first layer. It can be evaporated.

JP 2002-268066 A JP 2002-277879 A

  However, according to the method described in Patent Document 1, there is a risk that adverse effects such as a decrease in the aperture ratio may occur due to the spread of the light shielding region. In addition, in the method described in Patent Document 2, it may take twice to form an alignment film by forming two layers, and it may take time to set relative conditions such as the deposition direction of each layer. That is, a new problem arises that the required period from specification determination to shipment, that is, TAT (Turn Around Time) is extended, and the manufacturing efficiency is lowered.

  The present invention has been made in view of the above-described problems, and an electro-optical device capable of high-quality display and capable of being efficiently manufactured, a manufacturing method thereof, and an electron including such an electro-optical device. It is an object to provide a device.

  In order to solve the above problems, an electro-optical device manufacturing method according to the present invention includes an electric optical material including a pair of substrates having an alignment film formed on at least one surface thereof, and an electro-optical material sandwiched between the pair of substrates. An electro-optical device manufacturing method for manufacturing an optical device, wherein oblique deposition at a predetermined deposition angle is performed on a substrate surface having a stripe-shaped step in at least one of the pair of substrates. An alignment film forming step for forming an alignment film, which is performed along a deposition direction set within a range in which the alignment failure of the electro-optic material due to the step does not occur with reference to the extending direction of the step; After the alignment film forming step, an assembly step is performed in which the pair of substrates are opposed to each other with the surface on which the alignment film is formed facing inside, and the electro-optical material is injected between the pair of substrates.

  According to the method for manufacturing an electro-optical device of the present invention, in the alignment film forming step, the alignment film is formed by oblique vapor deposition using the substrate surface having a stripe-shaped step as a base. The alignment film is made of a vapor-depositable inorganic material such as SiO, and may be formed on one or both of the pair of substrates.

  In addition, this invention is applied when the stripe-shaped level | step difference has arisen on the base surface. The level difference is caused by, for example, the thickness of a wiring, element, light shielding film, or the like formed on the lower layer side of the base surface. Here, in particular, a case where the level difference is caused by a striped component such as the light shielding film is assumed. .

  In this case, the oblique vapor deposition for forming the alignment film is performed along the vapor deposition direction based on the extending direction of the step in the plane of the substrate surface. That is, since the vapor deposition beam is emitted along the direction in which the level difference on the base surface extends in a stripe shape, there is almost no area that becomes a shadow of the level difference, and vapor deposition spots are reduced or eliminated. Therefore, an alignment film having almost no spots can be formed by a single deposition.

  Although it is desirable that the vapor deposition direction completely coincides with the extending direction of the step, it is not easy to actually make both coincide perfectly. However, even if the vapor deposition direction is slightly deviated from the extending direction of the step, any configuration that exhibits the functions and effects of the present invention may be used. In other words, the vapor deposition direction may be set within an angle range in which alignment failure does not occur in the electro-optic material by the formed alignment film. Here, “no alignment failure does not occur” means that the actual damage due to the alignment failure, that is, a defect in display quality is within an allowable range. Such an “angle range in which orientation failure does not occur” may be determined individually, specifically, experimentally, empirically, theoretically, or by simulation, calculation, or the like according to the specifications of each electro-optical device. The deposition angle, that is, the angle or inclination angle of the deposition beam with respect to the normal of the substrate surface is not particularly limited here.

  After the alignment film forming process, in the assembly process, the pair of substrates are opposed with the surface on which the alignment film is formed facing inward, and an electro-optical material is injected between the pair of substrates. As described above, since the alignment film formed here has almost no spots, the electro-optic material sandwiched between the substrates in contact with the alignment film hardly causes alignment defects.

  Therefore, in the electro-optical device manufactured in this way, light leakage, a decrease in contrast ratio, and the like due to poor alignment of the electro-optical material are suppressed or eliminated, and good display is possible.

  As another solution to the above-mentioned problem (that is, the alignment film is uneven due to the presence of a step and a display defect occurs), for example, wiring is embedded in a substrate or an interlayer insulating film, or polishing is performed. Thus, it is conceivable to flatten the substrate surface. However, in such a method, there is a possibility that adverse effects on manufacturing may occur due to an increase in the number of processes. In that respect, it can be said that the present invention is more advantageous. In recent years, stripe-shaped steps are often intentionally provided at the boundary between adjacent lines on the surface of the substrate in order to suppress the generation of a lateral electric field associated with polarity inversion driving such as line inversion driving. In such a case, the surface of the substrate cannot be flattened. However, if the configuration according to the present invention is adopted, the above-mentioned problem can be solved while the step is left, which is very convenient.

  Compared to electro-optical devices with good display quality, an alignment film without vapor deposition spots is formed in the usual way, except that the in-plane direction of the vapor deposition beam on the substrate surface is set according to the level difference. Therefore, the manufacturing efficiency can be improved.

  In one aspect of the electro-optical device manufacturing method of the present invention, the vapor deposition direction is set according to at least (i) the size and shape of the step, (ii) the type of the electro-optical material, and (iii) the vapor deposition angle. Has been.

  According to this aspect, the vapor deposition direction is set according to at least the above three conditions. That is, the vapor deposition direction directly determines the direction of shape anisotropy of the alignment film. This is nothing but controlling the orientation direction of the electro-optic material. Similarly, the factors that determine the orientation direction of the electro-optic material are, for example, the type of electro-optic material comprising nematic material, cholestic material, etc., and the “deposition angle” already described, which are related to each other. Yes.

  (i) The size and shape of the step is an element that determines the size of the shadow of the step depending on the relative relationship between the deposition angle and the deposition direction. In addition, the dimension shape of a level | step difference points out the height of a level | step difference, a width | variety, a taper shape, the space | interval of a level | step difference, etc. specifically ,. In this case, more detailed condition setting is possible.

  In another aspect of the method of manufacturing the electro-optical device according to the aspect of the invention, the vapor deposition direction is set within ± 5 degrees with respect to the extending direction of the step.

  According to this aspect, a specific angle range in the vapor deposition direction that is compatible with an actually manufactured electro-optical device is set. That is, if the vapor deposition direction is within ± 5 degrees with respect to the extending direction of the step, the orientation state of the electro-optical material can be controlled well, so that it can be regarded as an error range.

  In order to solve the above problems, an electro-optical device of the present invention includes a pair of substrates, at least one of which includes a stepped surface having a stripe-shaped step, and an electro-optic sandwiched between the pair of substrates. A material and an alignment film having a shape anisotropy formed in a direction within a range in which the alignment failure of the electro-optic material does not occur with reference to the extending direction of the step. The alignment direction of the optical material is regulated according to the shape anisotropy.

  According to the electro-optical device of the present invention, the alignment film is formed so as to have shape anisotropy substantially along the extending direction of the step. Therefore, the alignment film has almost no spots due to the steps, and the alignment failure is hardly caused in the electro-optic material whose alignment direction is regulated by the alignment film.

  Therefore, in this electro-optical device, a decrease in display quality due to poor alignment of the electro-optical material is suppressed or eliminated, and a good display is possible.

  In one aspect of the electro-optical device of the present invention, the step is formed by the presence of a stripe-shaped light shielding film corresponding to the step.

  In any of the pair of substrates, the light shielding film is provided on the upper layer side in order to regulate the incident region of the incident light. The light shielding film is provided so as to cover a portion other than the opening region where the display electrode is provided, that is, a non-opening region, and is formed in a stripe shape or a lattice shape depending on the pixel shape. On the other hand, the alignment film is usually formed on the entire top surface of the substrate in order to control the alignment of the electro-optic material.

  That is, the alignment film is formed almost immediately above the light shielding film. For this reason, a level difference derived from the shape of the light shielding film is conspicuously generated on the surface serving as the base of the alignment film. Almost no influence. In other words, without changing the shape or the like of the light shielding film, embedding the light shielding film or wiring in the substrate or interlayer insulating film, or performing a CMP (Chemical Mechanical Polishing) process on the base surface, An alignment film can be formed uniformly.

  Such a light-shielding film may be formed so that a step with a certain size is generated for the purpose of suppressing a lateral electric field. According to the present invention, since the unevenness of the alignment film is reduced or eliminated while the step is left, it is particularly effective in such a case.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention (including various aspects thereof).

  According to the electronic apparatus of the present invention, since the above-described electro-optical device of the present invention is provided, high-quality display is possible and efficient manufacture is possible. This electronic device is, for example, a projection display device, a liquid crystal television, a mobile phone, an electronic notebook, a word processor, a viewfinder type or a monitor direct view type video tape recorder, a workstation, a video phone, a POS terminal, a touch panel, and various other electronic devices. Can be realized.

  Such an operation and other advantages of the present invention will become apparent from the embodiments described below.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<1: First Embodiment>
Before describing the manufacturing method of the electro-optical device according to the first embodiment, the configuration of the electro-optical device manufactured by applying the manufacturing method will be described with reference to FIGS. In the present embodiment, a liquid crystal device is taken as an example of a specific example of the electro-optical device according to the invention.

<1-1: Configuration of Electro-Optical Device>
The configuration of the electro-optical device according to this embodiment will be described with reference to FIGS. 1 to 3. FIG. 1 is a plan view of the electro-optical device according to the present embodiment when the TFT array substrate is viewed from the side of the counter substrate together with each component formed on the TFT array substrate, and FIG. 'Cross section. FIG. 3 shows a configuration of the counter substrate. In FIGS. 2 and 3, the vertical direction of the counter substrate is reversed. This electro-optical device employs a drive circuit built-in TFT active matrix drive system as a specific example of the present invention.

  1 and 2, the electro-optical device includes a TFT array substrate 10 and a counter substrate 20 which are arranged to face each other. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are provided with a sealing material 52 provided in a seal region positioned around the image display region 10a. Are bonded to each other.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or the like for bonding the two substrates, and is applied on the TFT array substrate 10 in the manufacturing process and then cured by ultraviolet irradiation, heating, or the like. It is. Further, in the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance (inter-substrate gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed.

  A light-shielding frame light-shielding film 53 that defines the frame area of the image display area 10a is provided on the counter substrate 20 side in parallel with the inside of the seal area where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side.

  Of the peripheral area of the image display area 10 a, the data line driving circuit 101 and the external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 in an area located outside the sealing area where the sealing material 52 is disposed. It has been. The scanning line driving circuit 104 is provided along two sides adjacent to the one side so as to be covered with the frame light shielding film 53. Further, in order to connect the two scanning line driving circuits 104 provided on both sides of the image display area 10a in this way, the TFT array substrate 10 is covered with the frame light shielding film 53 along the remaining side. A plurality of wirings 105 are provided.

  In addition, vertical conduction members 106 functioning as vertical conduction terminals between the two substrates are disposed at the four corners of the counter substrate 20. On the other hand, the TFT array substrate 10 is provided with vertical conduction terminals in a region facing these corners. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20.

  In FIG. 2, on the TFT array substrate 10, a pixel electrode 9a is provided in an upper layer of wiring such as a pixel switching TFT and a scanning line data line. An alignment film 16 is formed immediately above the pixel electrode 9a.

  In FIG. 3, a counter electrode 21 is formed on the counter surface of the counter substrate 20. As with the pixel electrode 9a, the counter electrode 21 is made of a transparent conductive film such as an ITO film. A striped light shielding film 23 is formed between the counter substrate 20 and the counter electrode 21 so as to cover a region facing the TFT in order to prevent generation of a light leakage current in the TFT. An alignment film 22 is provided further above the counter electrode 21.

On the surface of the counter electrode 21 that is the base of the alignment film 22, there is a step H caused by the stripe-shaped light shielding film 23. The alignment film 22 is made of an inorganic material formed by oblique vapor deposition, such as SiO ₂ , SiO, Al ₂ O _3, etc., and has a thickness of, for example, about 50 nm (500 mm). And it forms into a film by performing oblique vapor deposition along the extension direction of the level | step difference H so that it may mention later. Therefore, the alignment film 22 in the present embodiment has shape anisotropy in the extending direction of the step H.

  A liquid crystal layer 50 is provided between the TFT array substrate 10 and the counter substrate 20 configured as described above. The liquid crystal layer 50 is formed by sealing liquid crystal in a space formed by sealing the peripheral edges of the TFT array substrate 10 and the counter substrate 20 with a sealing material 52. The liquid crystal layer 50 takes a predetermined alignment state by the alignment film 16 and the alignment film 22 in a state where an electric field is not applied between the pixel electrode 9 a and the counter electrode 21.

  On the TFT array substrate 10, in addition to the data line driving circuit 101, the scanning line driving circuit 104, and the like, a sampling circuit for sampling an image signal on the image signal line and supplying it to the data line, a plurality of data lines are predetermined. A precharge circuit that supplies a precharge signal at a voltage level prior to the image signal, an inspection circuit for inspecting the quality, defects, etc. of the electro-optical device during manufacturing or at the time of shipment may be formed. .

<1-2: Manufacturing Method of Electro-Optical Device>
Next, a method for manufacturing such an electro-optical device will be described with reference to FIGS. FIG. 4 is a flowchart showing the manufacturing process of the electro-optical device, and FIG. 5 shows the configuration of the vapor deposition device used for forming the alignment film. 6 and 7 show the vapor deposition angle when the alignment film is deposited on the counter substrate 20, and FIG. 8 shows the vapor deposition direction. FIG. 9 shows a state of display in units of pixels of the electro-optical device thus manufactured. FIGS. 10 and 11 show a display method in units of pixels in a manufacturing method as a comparative example of the present embodiment and an electro-optical device manufactured thereby.

  In the flowchart of FIG. 4, first, a laminated structure is formed on the TFT array substrate 10 (step S11). This step can be performed as follows, for example. First, a glass substrate or a quartz substrate is prepared as the TFT array substrate 10, and a scanning line made of a metal alloy film such as a metal such as Ti, Cr, W, Ta, Mo and Pd or a metal silicide is sputtered thereon. A pattern is formed by photolithography and etching. Further thereon, a lower insulating film made of NSG is formed by, for example, normal pressure or low pressure CVD.

  Next, a polysilicon film is formed on the base insulating film, and a semiconductor layer having a predetermined pattern is formed by photolithography and etching. The surface of the semiconductor layer is thermally oxidized to form a gate insulating film, and then a gate electrode is formed by photolithography and etching. Further, impurity ions are doped using the gate electrode as a mask to form a source region and a drain region in the semiconductor layer, thereby forming a pixel switching TFT.

  Next, after forming a first interlayer insulating film made of an NSG film on the TFT, phosphorus (P) is thermally diffused into the polysilicon film to form a lower electrode, and a high temperature silicon oxide film (HTO film) or silicon nitride is formed. A dielectric film made of a film and a capacitor electrode made of a conductive polysilicon film are laminated to form a storage capacitor.

  Next, after forming a second interlayer insulating film made of an NSG film, data lines and the like are formed. Next, after forming a third interlayer insulating film, the upper surface thereof is planarized by CMP treatment. Specifically, for example, by rotating a liquid surface containing a silica particle (chemical polishing liquid) on a polishing pad fixed on a polishing plate and rotating the substrate surface fixed to the spindle, the third The upper surface of the interlayer insulating film is polished.

Next, an ITO film is deposited on the third interlayer insulating film by sputtering or the like, and photolithography and etching are performed to form the pixel electrode 9a. Further, an inorganic material such as SiO ₂ , SiO, Al ₂ O ₃ is obliquely deposited on the entire surface of the TFT array substrate 10 to form an alignment film 16 having a thickness of about 50 nm (500 mm).

  The vapor deposition apparatus applied in this case is configured as shown in FIG. 5, for example. This apparatus is an apparatus for vacuum vapor deposition, and includes an evaporation source 90 and a pelger 91 that is configured to support the vapor deposition substrate at a predetermined angle θ and can seal the inside. The central axis X2 of the TFT array substrate 10 is disposed so as to be inclined at an angle θ (0 ° <θ <90 °) with respect to the X1 axis indicating the straight traveling direction from the evaporation source 90. That is, at this time, the substrate surface of the TFT array substrate 10 is inclined by the angle θ from the traveling direction of the evaporation material. As a result, the material deposited on the TFT array substrate 10 grows so that columnar crystals with a predetermined angle are arranged. The alignment film 16 as the inorganic oblique vapor deposition film thus obtained can align the liquid crystal molecules of the liquid crystal layer 50 by the surface shape effect. The alignment film 16 is made of an inorganic material and thus has excellent light resistance and heat resistance, and contributes to improving the durability of the electro-optical device as a light valve. In this way, the stacked structure shown in FIG. 2 is formed on the TFT array substrate 10.

  A process of forming a predetermined structure also on the counter substrate 20 is performed in parallel with or before or after the structure forming process on the TFT array substrate 10 described above. That is, a glass substrate or the like is first prepared as the counter substrate 20, and a stripe-shaped light shielding film 23 is formed by sputtering metal chromium or the like on the entire surface, and performing photolithography and etching. Subsequently, an ITO film is deposited to a thickness of about 50 to 200 nm by sputtering to form the counter electrode 21 (step S12). At this time, a stripe-shaped step H is generated on the surface of the counter electrode 21 due to the presence of the light shielding film 23.

Next, an inorganic material such as SiO ₂ , SiO, Al ₂ O ₃ is obliquely deposited on the entire surface of the counter substrate 20 to form an alignment film 22 having a thickness of about 50 nm (500 mm) (step S13). In the present embodiment, this step corresponds to an example of the “alignment film forming step” of the present invention.

  Here, the alignment film 22 is formed at the deposition angle δ1 shown in FIG. The vapor deposition angle δ1 corresponds to the angle θ in FIG. 5, and there is a correspondence relationship as shown in FIG. 7 between the pretilt angle of the TN mode liquid crystal aligned by the alignment film 22. That is, the liquid crystal takes a two-phase state according to the deposition angle δ1 of the alignment film 22. When the vapor deposition angle δ1 is around 60 degrees, the liquid crystal is almost aligned with the substrate surface, but when the vapor deposition angle δ1 is around 80 degrees, the liquid crystal is oriented at a pretilt angle of about 30 degrees. Therefore, here, the vapor deposition angle δ1 is set to 80 degrees, for example.

  Further, in the present embodiment, the traveling direction of the evaporation material on the substrate surface, that is, the vapor deposition direction X3 in the surface of the substrate surface of the counter substrate 20 is set to a direction along the extending direction of the stripe-shaped step H. For this reason, a region that becomes a shadow of the step H during the vapor deposition hardly occurs physically, and the step H is prevented from being divided into a region where the substrate surface is vapor-deposited and a shadow region that is not vapor-deposited. Therefore, deposition spots in the alignment film 22 are reduced or eliminated.

  The vapor deposition direction X3 directly determines the crystal growth direction of the evaporation material and the shape anisotropy direction of the alignment film 22, and determines the liquid crystal alignment direction in the liquid crystal layer 50. Similarly, factors that determine the alignment direction of the liquid crystal include, for example, the type of liquid crystal and the vapor deposition angle, and these are mutually related as the vapor deposition conditions of the alignment film 22. Therefore, the vapor deposition direction X3 may be set not only in the extending direction of the step H but also in consideration of such other conditions.

  Thereafter, the TFT array substrate 10 and the counter substrate 20 on which the laminated structure is formed as described above are opposed to each other so that the alignment films 16 and 22 face each other, and are bonded together by the sealing material 52 (step S14).

  Next, a TN mode (Twisted Nematic) liquid crystal material having a positive dielectric anisotropy is injected into the space formed between the substrates, thereby forming a liquid crystal layer 50 having a predetermined thickness ( Step S15). The liquid crystal layer 50 is aligned at a pretilt angle of approximately 30 degrees due to the surface shape effect of the alignment films 16 and 22 that are inorganic oblique vapor deposition films. At that time, in particular, since the alignment film 22 is formed in a state free from vapor deposition spots, the alignment state of the liquid crystal in the liquid crystal layer 50 is uniformly regulated without any spots by the alignment film. The bonding process and the liquid crystal injection process correspond to an example of the “assembly process” of the present invention.

  The electro-optical device manufactured as described above can suppress or eliminate a decrease in display quality due to poor alignment of the liquid crystal in the liquid crystal layer 50, thereby enabling a good display.

  For example, when the image display area 10a in this case is enlarged, all the pixels are clearly displayed as shown in FIG. In the drawing, a region extending in the horizontal direction among the lattice-like regions around the pixels is a light shielding region corresponding to an example of the light shielding film 23.

  On the other hand, in the comparative example of this embodiment, as shown in FIG. 10, the alignment film corresponding to the alignment film 22 is formed with the direction orthogonal to the step H as the vapor deposition direction X3 '. In the oblique deposition, a region that is not deposited by shadowing of the step H remains along the light shielding film 23, so that deposition spots occur in the formed alignment film. As a result, an alignment defect occurs in the liquid crystal layer 50 in accordance with the unevenness of the alignment film. That is, as shown in FIG. 11, the image display area 10a 'in this case includes a display defect area 10aa'. The display defect area 10aa 'is caused by the deposition spots of the alignment film, and is generated in the corresponding area. If the display defect region 10aa ′ having a weak liquid crystal alignment regulating force is formed at the peripheral edge of the pixel in this way, it can cause a liquid crystal alignment defect due to a lateral electric field, and further display quality deterioration such as a decrease in contrast ratio. Bring. The lateral electric field refers to an electric field in a direction parallel to the substrate surface, which is generated between electrodes of opposite polarity among the adjacent pixel electrodes 9a in an electro-optical device employing an inversion driving method. Accordingly, the lateral electric field causes liquid crystal modulation defects such as light leakage.

  As described above, in this embodiment, when the alignment film 22 is obliquely deposited on the counter substrate 20, the deposition direction X3 in the surface of the substrate surface is set in a direction along the extending direction of the step H. In spite of the vapor deposition, the step H does not affect the film formation state, so that the alignment film 22 having almost no spots can be formed by one vapor deposition. For this reason, a decrease in contrast ratio due to poor alignment of the liquid crystal is suppressed. Further, since the alignment regulating force of the liquid crystal is improved over the entire surface of the image display area 10a, it is possible to suppress a reduction in contrast ratio due to a modulation defect due to a lateral electric field. Therefore, it is possible to manufacture an electro-optical device that can suppress or eliminate a decrease in display quality and can perform good display. At the same time, in the generally known method for forming an alignment film without spots, it is necessary to form two layers. However, the number of steps is reduced because only one layer is required here. Therefore, manufacturing efficiency can be improved.

  In addition, this embodiment can form an alignment film without vapor deposition spots by a normal method, except for the setting of the vapor deposition direction X3. Therefore, an electro-optical device with good quality can be manufactured relatively easily. be able to. Therefore, manufacturing efficiency can be improved.

  By the way, it is desirable that the vapor deposition direction X3 is completely matched with the extending direction of the step H from the viewpoint of eliminating the influence of the step H from the film formation state, but it is assumed that it is slightly shifted from the extending direction of the step. However, substantial effects and effects can be sufficiently expected. Accordingly, the vapor deposition direction X3 only needs to be set within a range in which the alignment film 22 to be formed does not cause alignment failure in the liquid crystal layer 50 (that is, a defect in display quality is within an allowable range).

  Specifically, the vapor deposition direction X3 may be set within ± 5 degrees with respect to the extending direction of the step H (see FIG. 8). This angle range is based on knowledge obtained from experiments by the inventors of the present invention (see FIGS. 14 and 15 and the like), as will be described later as examples. That is, if the deposition direction is within ± 5 degrees with respect to the extending direction of the step, display spots due to the alignment failure of the liquid crystal layer 50 hardly occur.

  Note that the alignment film 16 on the TFT array substrate 10 side uses the third interlayer insulating film subjected to CMP as a base surface, so that film formation defects due to steps are hardly a problem. Although not applied, when the unevenness of the base surface becomes a problem, it may be formed in the same manner as the alignment film 22.

<2: Second Embodiment>
Next, a second embodiment will be described with reference to FIGS. Here, FIG.12 and FIG.13 represents the vapor deposition angle at the time of vapor-depositing an alignment film on a counter substrate.

  This embodiment is different from the first embodiment except that the type of liquid crystal used is different from that of the first embodiment and that the deposition angle of the alignment film 25 formed on the counter substrate 20 is different from the deposition angle of the first embodiment. This is the same as in the first embodiment. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

  Here, the liquid crystal constituting the liquid crystal layer 50 is a liquid crystal having negative dielectric anisotropy and being in a VAN (Vertical Alignment Nematic) mode. Therefore, in FIG. 12, the alignment film 25 is deposited at a deposition angle δ2. The vapor deposition angle δ2 has a correspondence relationship with the pretilt angle of the VAN mode liquid crystal aligned by the alignment film 25 as shown in FIG. That is, with respect to the deposition angle δ2 of the alignment film 25, the pretilt angle of the liquid crystal changes to a downward convex curve with a magnitude close to 90 degrees. Therefore, here, the vapor deposition angle δ2 is set to 45 degrees, which is a substantially minimum value.

  The vapor deposition direction X3 is set similarly to the first embodiment. As a result, a region that becomes a shadow of the step H during the vapor deposition hardly occurs physically, and the vapor deposition spots in the alignment film 25 are reduced or eliminated.

  Therefore, also in this embodiment, the same effect as the first embodiment is exhibited.

<3: Electronic equipment>
The liquid crystal device described above can be applied to, for example, a projector. Here, a projector in which the electro-optical device according to the embodiment is applied to a light valve will be described as an example of the electronic apparatus of the invention. FIG. 14 shows a configuration example of such a projector. As shown in this figure, a lamp unit 1102 including a white light source such as a halogen lamp is provided inside the projector 1100. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 disposed in the light guide, and an electric valve as a light valve corresponding to each primary color. The light enters the optical devices 100R, 100B, and 100G. Here, the configurations of the electro-optical devices 100R, 100B, and 100G are the same as those of the above-described electro-optical device, and R, G, and B primary color signals supplied from the image signal processing circuit are modulated. The light modulated by the electro-optical devices 100R, 100B, and 100G enters the dichroic prism 1112 from three directions. In the dichroic prism 1112, R and B light is refracted by 90 degrees, while G light travels straight. As a result, the images of the respective colors are combined, and a color image is projected onto the screen 1120 and the like via the projection lens 1114.

  The electro-optical device according to the above-described embodiment can also be applied to a direct-view type or reflective type color display device other than the projector. In that case, an RGB color filter may be formed together with the protective film in a region facing the pixel electrode 9 a on the counter substrate 20. Alternatively, it is also possible to form a color filter layer with a color resist or the like under the pixel electrodes 9 a facing the RGB on the TFT array substrate 10. Furthermore, in each of the above cases, if a microlens corresponding to the pixel on the counter substrate 20 is provided on a one-to-one basis, the light collection efficiency of incident light can be improved and the display luminance can be improved. Furthermore, a dichroic filter that creates RGB colors by using interference of light may be formed by depositing multiple layers of interference layers having different refractive indexes on the counter substrate 20. According to this counter substrate with a dichroic filter, brighter display is possible.

  Next, an embodiment according to the present invention will be described with reference to FIGS.

<Example 1>
In the same manner as in the first embodiment, an electro-optical device using a TN mode nematic liquid crystal having a positive dielectric anisotropy is manufactured. When forming the alignment film on the counter substrate, according to the manufacturing process of the first embodiment, oblique deposition is performed with a deposition angle of 80 degrees and a deposition direction based on the extending direction of the stripe-shaped step on the substrate surface. The thickness is 50 nm (500 mm). In this case, as parameters, (1) the deposition direction is changed stepwise from 0 to 20 degrees from the extending direction of the stripe-shaped step, and (2) the thickness of the light shielding film is 55 nm, 85 nm, 110 nm, Change the height of the step by changing it to 200 nm. And in each case, the length of the shadow of the level | step difference of the light shielding film with respect to a vapor deposition direction is measured.

  FIG. 15 shows the evaluation result of whether or not alignment defects occur in the liquid crystal based on the measured value of the shadow length of the step. The length of the shadow of the step is an indicator of the size of the region where the liquid crystal alignment is poor. Specifically, if the shadow length is 100 nm or less, the orientation is good (◯ in the figure), and if it is in the range from 100 nm to less than 150 nm, the orientation is partially poor (Δ in the figure). In this case, the alignment defect is in a state that cannot be ignored (× in the figure).

  That is, in order to obtain the effect of the present invention, for example, when the height of the step is 110 nm or more and 200 nm or less, the deviation angle is desirably within 7 degrees, and preferably within 5 degrees is the best effect. Is obtained.

  Further, when the height of the step is 85 nm or more and 110 nm or less, the deviation angle is preferably within 12 degrees, and more preferably within 7 degrees.

  In this result, the tendency that alignment defects are more likely to occur as the step becomes higher and the deposition direction deviates from the extending direction of the step. The size of the shadow of the step during oblique deposition naturally depends on the size of the step and the deposition direction. And even if the level difference is large to some extent (regardless of the size of the level difference in the realistic size range), the vapor deposition direction that can finally maintain a good alignment state has a deviation of 5 degrees from the direction in which the level difference extends. This is the case. That is, in the present invention, if the deposition direction is approximately 5 degrees within the error range and along the extending direction of the step, an alignment film free from deposition spots can be obtained, and the above-described effects can be obtained. It is considered possible.

<Example 2>
In the same manner as in the second embodiment, an electro-optical device using a VAN mode nematic liquid crystal having a negative dielectric anisotropy is manufactured. When forming the alignment film on the counter substrate, according to the manufacturing process of the second embodiment, oblique deposition is performed with a deposition angle of 45 degrees and a deposition direction based on the extending direction of the stripe step on the substrate surface. The thickness is 50 nm (500 mm). In this case, the parameters are changed in the same manner as in Example 1, and in each case, the shadow length of the step of the light shielding film with respect to the deposition direction is measured.

  FIG. 16 shows the evaluation result as to whether or not alignment failure occurs in the liquid crystal based on the measured value of the shadow length of the step. The length of the shadow of the step is an indicator of the size of the region where the liquid crystal alignment is poor. Specifically, if the shadow length is 20 nm or less, the orientation is good (◯ in the figure), and if it is in the range from 20 nm to less than 30 nm, a part of the orientation is poor (Δ in the figure). In this case, the alignment defect is in a state that cannot be ignored (× in the figure). Incidentally, when the liquid crystal is in the VAN mode, the driving method is a normally black mode. Accordingly, even if a slight alignment failure occurs, black display is obtained and the contrast ratio is greatly reduced. Therefore, the evaluation criteria are set more strictly than the TN mode which is normally white.

  In this case as well, almost the same result as in Example 1 is obtained, and in the oblique deposition according to the present invention, the deposition direction along the extending direction of the step should be approximately 5 degrees within the error range. That is supported.

<Example 3>
When there is a slight deviation from the extending direction of the step in the vapor deposition direction as in Example 1 and Example 2, the size of the shadow of the step is the size of the step, that is, the height, width, and taper of the step. It depends on the shape and the interval between steps. Therefore, the vapor deposition direction in such a case needs to be set in consideration of the dimensional shape of the step.

  Therefore, the electro-optical device is manufactured and evaluated under the same conditions as in Example 1 except that the taper angle of the step is used as a parameter instead of the height of the step. That is, in FIG. 17, the taper angle α is changed to 0 degree, 50 degrees, 65 degrees, and 80 degrees with the deviation of the vapor deposition direction. It is expected that the shadow of the step becomes smaller as the taper angle α is smaller. In this case, the height of the step is fixed to 110 nm.

  FIG. 18 shows an evaluation result of whether or not alignment failure occurs in the liquid crystal based on the measured value of the shadow length of the step. Actually, although it is slight, there is a tendency that the smaller the taper angle α is, the more the tolerance of the deposition direction can be tolerated. As described above, the range in which the oblique vapor deposition according to the present invention can be performed on both changes depending on the shape of the step formed by the light shielding film or the like.

  In the embodiments and examples, the liquid crystal device has been described as an example of the electro-optical device according to the present invention. However, the present invention may cause display quality to be deteriorated as a result of unevenness in the film formation state due to a step on the surface. It can also be applied to the manufacture of other electro-optical devices as caused.

  The present invention is not limited to the above-described embodiments and examples, and can be appropriately changed without departing from the spirit or idea of the invention that can be read from the claims and the entire specification, and is accompanied by such changes. The manufacturing method of the electro-optical device, the electro-optical device, and the electronic apparatus are also included in the technical scope of the present invention.

1 is a plan view showing an overall configuration of an electro-optical device according to a first embodiment. It is I-I 'sectional drawing of FIG. FIG. 3 is a cross-sectional view illustrating a counter substrate in the electro-optical device according to the first embodiment. It is a flowchart of the manufacturing method which concerns on 1st Embodiment. It is sectional drawing showing schematic structure of the vapor deposition apparatus which concerns on 1st Embodiment. It is a perspective view showing the vapor deposition angle in the oblique vapor deposition of the orientation film on the counter substrate side. It is a graph showing the pretilt angle of the liquid crystal with respect to the vapor deposition angle in the oblique vapor deposition shown in FIG. It is a top view showing the vapor deposition direction in oblique vapor deposition of the alignment film on the counter substrate side. FIG. 3 is a plan view illustrating a display state in the electro-optical device according to the first embodiment. It is a top view showing the vapor deposition direction in the oblique vapor deposition of the alignment film by the side of the opposing substrate based on the comparative example of 1st Embodiment. 6 is a plan view illustrating a display state in an electro-optical device according to a comparative example of the first embodiment. FIG. It is a perspective view showing the vapor deposition angle in oblique vapor deposition of the alignment film which concerns on 2nd Embodiment. It is a graph showing the pretilt angle of the liquid crystal with respect to the vapor deposition angle in the oblique vapor deposition shown in FIG. It is sectional drawing showing the structure of the liquid crystal projector which concerns on one Embodiment of the electronic device of this invention. 6 is a table of evaluation results of liquid crystal alignment states when the height of the light shielding film on the counter substrate and the deviation in the deposition direction are changed in the electro-optical device according to Example 1. 6 is a table of evaluation results of liquid crystal alignment states when the height of a light-shielding film on a counter substrate and a shift in a deposition direction are changed in the electro-optical device according to Example 2. 6 is a cross-sectional view illustrating the shape of a light shielding film on a counter substrate in an electro-optical device according to Example 3. FIG. 12 is a table of evaluation results of liquid crystal alignment states when the taper angle of the light shielding film on the counter substrate and the deviation in the vapor deposition direction are changed in the electro-optical device according to Example 3.

Explanation of symbols

9a ... pixel electrode, 10 ... TFT array substrate, 10a ... image display area, 10aa '... display failure area, 20 ... counter substrate, 21 ... counter electrode, 22 ... alignment film, 23 ... light shielding film, 50 ... liquid crystal layer, H ... Step, δ1, δ2 ... Vapor deposition angle, X3 ... Vapor deposition direction.

Claims (6)

An electro-optical device manufacturing method for manufacturing an electro-optical device comprising a pair of substrates having an alignment film formed on at least one surface and an electro-optical material sandwiched between the pair of substrates,
Diagonal vapor deposition at a predetermined vapor deposition angle is applied to a substrate surface having a stripe-shaped step in at least one of the pair of substrates, resulting from the step in the plane of the substrate surface with respect to the extending direction of the step. An alignment film forming step for forming an alignment film, which is performed along a deposition direction set within a range in which the alignment failure of the electro-optic material does not occur;
And an assembly step of injecting the electro-optic material between the pair of substrates, with the alignment film forming step facing the pair of substrates with the surface on which the alignment film is formed facing inside. A method for manufacturing an electro-optical device.   2. The vapor deposition direction according to claim 1, wherein the vapor deposition direction is set in accordance with at least (i) the size and shape of the step, (ii) the type of the electro-optic material, and (iii) the vapor deposition angle. Manufacturing method of electro-optical device.   The method of manufacturing an electro-optical device according to claim 1, wherein the vapor deposition direction is set within ± 5 degrees with respect to the extending direction of the step. A pair of substrates at least one of which includes a stepped surface having a stripe-shaped step;
An electro-optic material sandwiched between the pair of substrates;
An alignment film formed using the step surface as a base and having shape anisotropy in a direction within a range in which the alignment failure of the electro-optic material does not occur with reference to the extending direction of the step,
The electro-optical device is characterized in that an orientation direction of the electro-optical material is regulated according to the shape anisotropy.   The electro-optical device according to claim 4, wherein the step is formed by the presence of a striped light shielding film corresponding to the step. An electronic apparatus comprising the electro-optical device according to claim 4.

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