JP2012078680A - Electro-optical device, method for manufacturing electro-optical device and electronic equipment - Google Patents

Abstract

To provide an electro-optical device, a method for manufacturing the electro-optical device, and an electronic apparatus that can obtain high reliability and stable optical characteristics.
A liquid crystal device 100 as an electro-optical device includes a liquid crystal layer 50 having negative dielectric anisotropy sandwiched between a pair of substrates, and a pixel electrode of an element substrate 10 as at least one of the pair of substrates. 15 and the surface of the common electrode 23 of the counter substrate 20 as the other substrate, and the insulating films 17 and 25 covering at least the side wall portions of the unevenness and the electrodes including the insulating films 17 and 25 And alignment films 18 and 24 as inorganic alignment films covering the surface.
[Selection] Figure 4

Description

  The present invention relates to an electro-optical device, a method for manufacturing the electro-optical device, and an electronic apparatus.

  As the electro-optical device, a liquid crystal device having a liquid crystal layer between a pair of substrates is known, and the initial alignment direction of liquid crystal molecules in the liquid crystal layer is controlled by an alignment film formed on the surface of the pair of substrates. Has been. For example, a liquid crystal having negative dielectric anisotropy uses an inorganic alignment film formed by obliquely depositing an inorganic material such as silicon oxide on the substrate surface.

  In such a method for forming an inorganic alignment film by oblique deposition, if irregularities are formed on the substrate on which the inorganic alignment film is formed, when oblique deposition is performed on the irregularities, A shadowed portion, that is, a portion in which an alignment film is difficult to be formed occurs, and uneven alignment of liquid crystal molecules may occur. The structure which solves such a subject is disclosed by patent document 1-patent document 3, for example.

In the liquid crystal device of Patent Document 1, the base layer of at least one of the inorganic alignment films has irregularities, and the slopes on the side along the oblique vapor deposition direction of the inorganic material of the convex portion or the concave portion of the base layer and the oblique vapor deposition direction The inclination angle of the slope on the facing side is different.
In the liquid crystal display device of Patent Document 2, at least one of the alignment films is formed by oblique vapor deposition from a first layer formed by oblique vapor deposition and an azimuth angle of 180 ° with respect to the first layer. And a laminated structure with the second layer.
In the liquid crystal device disclosed in Patent Document 3, an inorganic alignment film is formed on an alignment base film made of an aggregate of fine particles on a substrate. An ITO fine particle having optical transparency is mentioned as an aggregate.

JP 2002-268067 A JP 2005-181794 A JP 2007-178699 A

However, in the method for forming an inorganic alignment film in Patent Document 1 and Patent Document 2, it is difficult to form the inorganic alignment film so as to completely cover the uneven surface generated in various directions on the substrate surface. Therefore, a portion where the surface of the electrode provided on each of the pair of substrates is not covered with the inorganic alignment film is generated, and the electrode and the liquid crystal layer are in direct contact with the portion. Then, when a driving voltage is applied to the electrodes, electric charges are discharged from the corresponding portion of the electrodes to the liquid crystal layer, and the driving voltage applied between the electrodes facing each other between the pair of substrates fluctuates to reduce display quality. There was a problem that a problem might occur.
In addition, the method for forming an inorganic alignment film in Patent Document 3 requires an alignment base film having a thickness enough to fill the unevenness and flatten the surface. Even if ITO fine particles are used as aggregates, the alignment film is aligned. As compared with the case where no base film is provided, there is a problem that the transmittance in the pixel is reduced and the contrast may be lowered.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms or application examples.

  Application Example 1 An electro-optical device according to this application example is an electro-optical device in which a liquid crystal layer having negative dielectric anisotropy is sandwiched between a pair of substrates, and at least one of the pair of substrates. And an inorganic alignment film covering the surface of at least one substrate including the electrode and the insulating film.

  According to this configuration, since at least the side wall portion of the electrode of at least one of the pair of substrates is covered with the insulating film, for example, even if the inorganic alignment film is formed by using the vapor deposition method, An inorganic alignment film can be provided without exposing the side wall portion of the electrode. As a result, the liquid crystal layer is in contact with the insulating film or the inorganic alignment film, the charge transfer from the electrode to the liquid crystal layer is suppressed, and the liquid crystal layer is driven stably, so that the electro-optical device having excellent display quality Can provide.

Application Example 2 In the electro-optical device according to the application example described above, it is preferable that the electrode has unevenness on a surface, and the insulating film is provided so as to further cover a side wall portion of the unevenness.
According to this configuration, since the uneven side wall portion on the surface of the electrode of at least one of the pair of substrates is further covered with the insulating film, the inorganic alignment film is formed using, for example, a vapor deposition method. However, the inorganic alignment film can be provided without exposing the uneven side wall portion. As a result, the liquid crystal layer is in contact with the insulating film or the inorganic alignment film, the charge transfer from the electrode to the liquid crystal layer is suppressed, and the liquid crystal layer is driven stably, so that the electro-optical device having excellent display quality Can provide.

Application Example 3 In the electro-optical device according to the application example, the one substrate includes a pixel circuit, a plurality of pixel electrodes as the electrodes, and the inorganic alignment film that covers the pixel electrodes, The other of the substrates has a common electrode facing the plurality of pixel electrodes across the liquid crystal layer, and the inorganic alignment film covering the common electrode, and the unevenness on the pixel electrode is: The pixel circuit corresponds to the position where the pixel circuit is provided.
According to this configuration, even if the unevenness due to the pixel circuit is generated on the pixel electrode on one substrate, the sidewall portion of the unevenness is covered with the insulating film, and the surface on the pixel electrode other than the sidewall portion is Since it is covered with the inorganic alignment film, the pixel electrode is not exposed to the liquid crystal layer. Therefore, the discharge of charges from the pixel electrode to the liquid crystal layer is suppressed, and excellent display quality can be realized.

Application Example 4 In the electro-optical device according to the application example, the one substrate includes a plurality of pixel electrodes as the electrodes and the inorganic alignment film covering the pixel electrodes, The other substrate has a common electrode facing the plurality of pixel electrodes across the liquid crystal layer, and the inorganic alignment film covering the common electrode, and the unevenness on the pixel electrode is formed on the pixel electrode. It may be provided at the outer edge.
According to this configuration, by providing unevenness on the outer edge portion of the pixel electrode, it is possible to reduce the influence of a lateral electric field generated between adjacent pixel electrodes, and the uneven portion does not directly touch the liquid crystal layer. The emission of charges from the liquid crystal layer to the liquid crystal layer is suppressed, and a better display quality can be realized.

Application Example 5 In the electro-optical device according to the application example described above, the one substrate includes a plurality of pixel electrodes as the electrodes and the inorganic alignment film that covers the pixel electrodes. The other substrate includes a light shielding film that divides pixels in a plane, an interlayer film layer that covers the light shielding film, a common electrode that covers the interlayer film layer and faces the plurality of pixel electrodes, and the common The inorganic alignment film covering the electrode may be provided, and the unevenness on the common electrode may correspond to a position where the light shielding film is provided.
According to this configuration, even when the unevenness due to the light shielding film is generated on the common electrode in the other substrate, the side wall portion of the unevenness is covered with the insulating film, and the surface on the common electrode other than the side wall portion is Since it is covered with the inorganic alignment film, the common electrode is not exposed to the liquid crystal layer. Therefore, the discharge of charges from the common electrode to the liquid crystal layer is suppressed, and excellent display quality can be realized.

  Application Example 6 A method for manufacturing an electro-optical device according to this application example is a method for manufacturing an electro-optical device in which a liquid crystal layer having negative dielectric anisotropy is sandwiched between a pair of substrates. An electrode forming step of forming an electrode on at least one substrate, an insulating film forming step of forming an insulating film covering at least a side wall portion of the electrode, and an inorganic alignment film covering a surface of the electrode including the insulating film An alignment film forming step formed using a vapor phase growth method, wherein the insulating film forming step includes a step of forming the insulating film so as to cover the electrode, and a surface of the electrode facing the liquid crystal layer Removing the insulating film on the electrode so as to be exposed.

  According to this method, in the alignment film forming step, the inorganic alignment film can be formed by reliably covering the surface having the electrodes. In other words, it is possible to manufacture an electro-optical device having excellent display quality by preventing discharge of charges from the electrode to the liquid crystal layer without exposing the electrode to the liquid crystal layer. Further, since the insulating film formed on the surface of the electrode facing the liquid crystal layer is removed, an increase in driving voltage and a decrease in transmittance due to the provision of the insulating film on the electrode can be suppressed.

Application Example 7 In the method of manufacturing an electro-optical device according to the application example, the insulating film forming step includes leaving the insulating film on at least a side wall portion of the unevenness of the electrode, and having a surface facing the liquid crystal layer of the electrode. The insulating film on the electrode is preferably removed so as to be exposed.
According to this method, in the alignment film forming step, the inorganic alignment film can be formed by reliably covering the uneven surface of the electrode. In other words, it is possible to manufacture an electro-optical device having excellent display quality by suppressing discharge of charges from the electrode to the liquid crystal layer without exposing the uneven electrode to the liquid crystal layer.

Application Example 8 An electronic apparatus according to this application example includes the electro-optical device according to the application example described above.
According to this configuration, an electronic apparatus including an electro-optical device having excellent display quality can be provided.

(A) is a schematic plan view which shows the structure of a liquid crystal device, (b) is a schematic sectional drawing cut | disconnected by the H-H 'line | wire of (a). FIG. 3 is an equivalent circuit diagram illustrating an electrical configuration of the liquid crystal device. FIG. 2 is a schematic plan view showing a structure of a pixel. FIG. 3 is a schematic cross-sectional view illustrating a structure of a pixel according to the first embodiment. (A)-(c) is a schematic sectional drawing which shows the manufacturing method of the liquid crystal device in Example 1. FIG. FIG. 6 is a schematic plan view illustrating a configuration of a pixel according to Embodiment 2. FIG. 7 is a schematic cross-sectional view showing the structure of a pixel of Example 2 taken along line B-B ′ in FIG. 6. Schematic which shows the structure of the projection type display apparatus as an electronic device. FIG. 6 is a schematic cross-sectional view illustrating a pixel structure of a liquid crystal device according to a modification.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, embodiments of the invention will be described with reference to the drawings. Note that the drawings to be used are appropriately enlarged or reduced so that the part to be described can be recognized.

  In the following embodiments, when “on the substrate” is described, the substrate is disposed so as to be in contact with the substrate, or is disposed on the substrate via another component, or the substrate. It is assumed that a part is arranged so as to be in contact with the upper part and a part is arranged via another component.

  In the present embodiment, an active matrix liquid crystal device as an electro-optical device including a thin film transistor (TFT) as a pixel switching element will be described as an example. This liquid crystal device can be suitably used as, for example, a light modulation element (liquid crystal light valve) of a projection type display device (liquid crystal projector) described later.

<Liquid crystal device>
First, a liquid crystal device as an electro-optical device according to this embodiment will be described with reference to FIGS. 1 and 2. 1A is a schematic plan view showing the configuration of the liquid crystal device, FIG. 1B is a schematic cross-sectional view taken along line HH ′ of FIG. 1A, and FIG. 2 is an electrical configuration of the liquid crystal device. FIG.

  As shown in FIGS. 1A and 1B, a liquid crystal device 100 according to the present embodiment includes an element substrate 10 as one of a pair of substrates, a counter substrate 20 as the other substrate, and these And a liquid crystal layer 50 sandwiched between a pair of substrates. As the element substrate 10 and the counter substrate 20, a transparent glass substrate such as quartz is used.

  The element substrate 10 is slightly larger than the counter substrate 20, and both the substrates are joined via a seal material 40 arranged in a frame shape, and a liquid crystal having negative dielectric anisotropy is sealed in the gap to form a liquid crystal layer 50. For the sealing material 40, for example, an adhesive such as a thermosetting or ultraviolet curable epoxy resin is employed. A spacer (not shown) is mixed in the sealing material 40 to keep the distance between the pair of substrates constant.

  A light shielding film 21 is similarly provided in a frame shape inside the sealing material 40 arranged in a frame shape. The light shielding film 21 is made of, for example, a light shielding metal or metal oxide, and the inside of the light shielding film 21 is a display region E having a plurality of pixels P. Although not shown in detail in FIG. 1, the light shielding film 21 is provided on the counter substrate 20 side so as to divide the pixels P in the display area E in a plane.

A data line driving circuit 101 is provided between the element substrate 10 and the sealing material 40 along one side. Further, an inspection circuit 103 is provided inside the sealing material 40 along the other one side facing the one side. Further, a scanning line driving circuit 102 is provided inside the sealing material 40 along the other two sides orthogonal to the one side and facing each other. A plurality of wirings 105 that connect the two scanning line driving circuits 102 are provided inside the sealing material 40 on the other side facing the one side. Wirings connected to the data line driving circuit 101 and the scanning line driving circuit 102 are connected to a plurality of external connection terminals 104 arranged along the one side.
Hereinafter, the direction along the one side will be referred to as the X direction, and the direction along the other two sides orthogonal to the one side and facing each other will be described as the Y direction.
The arrangement of the inspection circuit 103 is not limited to this, and the inspection circuit 103 may be provided at a position along the inner side of the sealing material 40 between the data line driving circuit 101 and the display area E.

  As shown in FIG. 1B, on the surface of the element substrate 10 on the liquid crystal layer 50 side, a light-transmitting pixel electrode 15 provided for each pixel P, a thin film transistor 30 as a switching element, and a signal wiring And the alignment film 18 which covers these is formed.

  On the surface of the counter substrate 20 on the liquid crystal layer 50 side, a light shielding film 21, an interlayer film layer 22 formed so as to cover the light shielding film 21, and a common electrode 23 provided so as to cover the interlayer film layer 22 are shared. An alignment film 24 covering the electrode 23 is provided.

  As shown in FIG. 1A, the light shielding film 21 is provided in a frame shape at a position where the data line driving circuit 101, the scanning line driving circuit 102, and the inspection circuit 103 overlap in plan view. Thus, the light incident from the counter substrate 20 side is shielded, and the malfunction of the peripheral circuits including these drive circuits due to the light is prevented. Further, unnecessary stray light is shielded from entering the display area E, and high contrast in the display of the display area E is ensured.

  The interlayer film layer 22 is made of an inorganic material such as silicon oxide, for example, and is provided so as to cover the light shielding film 21 with light transmittance. Examples of a method for forming such an interlayer film layer 22 include a method of forming the inorganic material using a plasma CVD method or the like.

  The common electrode 23 is made of, for example, a transparent conductive film such as ITO, and covers the interlayer film layer 22 and, as shown in FIG. 1A, the element substrate 10 side by the vertical conduction parts 106 provided at the four corners of the counter substrate 20. It is electrically connected to the wiring.

The alignment film 18 that covers the pixel electrode 15 and the alignment film 24 that covers the common electrode 23 are formed by vapor phase growth using an inorganic material such as SiO _x (silicon oxide). In the vapor phase growth method, the substrate on which the alignment films 18 and 24 are formed and the emission source that emits the inorganic material are arranged so as to be inclined with respect to the normal direction of the substrate. Examples thereof include oblique vapor deposition and oblique sputtering. According to such a method of forming the alignment films 18 and 24, the liquid crystal molecules can be substantially vertically aligned in a state where a pretilt is applied to the surfaces of the alignment films 18 and 24.

  As shown in FIG. 2, the liquid crystal device 100 is parallel to the plurality of scanning lines 3a and the plurality of data lines 6a that are insulated from each other and orthogonal to each other at least in the display region E with a certain distance from the scanning line 3a. The capacitor line 3b is arranged as described above.

  A TFT 30 and a storage capacitor 16 are provided in a region divided by the scanning line 3a, the data line 6a, the capacitor line 3b, and these signal lines, and these constitute a pixel circuit of the pixel P.

The gate of the TFT 30 is electrically connected to the scanning line 3a, and the source of the TFT 30 is electrically connected to the data line 6a. The pixel electrode 15 is electrically connected to the drain of the TFT 30.
The data line 6a is connected to the data line driving circuit 101 (see FIG. 1), and supplies image signals D1, D2,..., Dn supplied from the data line driving circuit 101 to the pixels P. The scanning line 3a is connected to a scanning line driving circuit 102 (see FIG. 1), and supplies scanning signals SC1, SC2,..., SCm supplied from the scanning line driving circuit 102 to each pixel P. The image signals D1 to Dn supplied from the data line driving circuit 101 to the data lines 6a may be supplied in column order in this order, or may be supplied for each of a plurality of adjacent data lines 6a for each group. Good. The scanning line driving circuit 102 sequentially supplies the scanning signals SC1 to SCm to the scanning line 3a as pulse signals that do not overlap each other at a predetermined timing.

In the liquid crystal device 100, the TFT 30 that is a switching element is turned on for a certain period by the input of the scanning signals SC1 to SCm, so that the image signals D1 to Dn supplied from the data line 6a are supplied to the pixel electrode 15 at a predetermined timing. It is the structure written in. The image signals D1 to Dn of a predetermined level supplied to the liquid crystal layer 50 through the pixel electrode 15 are held for a certain period between the pixel electrode 15 and the common electrode 23 arranged to face each other through the liquid crystal layer 50. The
In order to prevent the held image signals D1 to Dn from leaking, the holding capacitor 16 is connected in parallel with the liquid crystal capacitor formed between the pixel electrode 15 and the common electrode 23. The storage capacitor 16 is provided between the drain of the TFT 30 and the capacitor line 3b.

  Note that a data line 6a is connected to the inspection circuit 103 shown in FIG. 1A, and an operation defect or the like of the liquid crystal device 100 is confirmed by detecting the image signal in the manufacturing process of the liquid crystal device 100. Although it can be configured, it is omitted in the equivalent circuit of FIG. The inspection circuit 103 includes a sampling circuit that samples the image signal and supplies it to the data line 6a, and a precharge circuit that supplies a precharge signal of a predetermined voltage level to the data line 6a prior to the image signal. Also good.

  Such a liquid crystal device 100 is a transmission type, and adopts an optical design of a normally white mode in which the pixel P is brightly displayed when not driven and a normally black mode in which the pixel P is darkly displayed when not driven. Polarizing elements are arranged and used according to the optical design on the light incident side and the light exit side, respectively.

  FIG. 3 is a schematic plan view showing the structure of the pixel. As shown in FIG. 3, the pixel P in the liquid crystal device 100 has, for example, a substantially rectangular opening in a plan view. The opening is surrounded by a light-shielding non-opening that extends in the X and Y directions and is provided in a lattice shape.

  The scanning line 3a and the capacitive line 3b shown in FIG. 2 are provided in the non-opening that extends in the X direction. In other words, at least a part of the non-opening is constituted by the scanning line 3a and the capacitor line 3b made of the low resistance wiring material.

  Similarly, the data line 6a shown in FIG. 2 is provided in the non-opening extending in the Y direction. In other words, at least a part of the non-opening is constituted by the data line 6a made of the low resistance wiring material.

  The non-opening is not only constituted by the signal lines provided on the element substrate 10 side, but also by the light shielding film 21 patterned in a lattice shape or a stripe shape corresponding to the display region E on the counter substrate 20 side. Is also configured.

  The TFT 30 and the storage capacitor 16 shown in FIG. 2 are provided near the intersection of the non-opening. By providing the TFT 30 in the vicinity of the intersection of the non-opening portions having a light shielding property, the TFT 30 is prevented from malfunctioning in light and the aperture ratio is secured.

  Next, a more specific structure of the pixel P in the liquid crystal device 100 will be described with examples. 4 is a schematic cross-sectional view illustrating the structure of the pixel according to the first embodiment, FIGS. 5A to 5C are schematic cross-sectional views illustrating a method for manufacturing the liquid crystal device according to the first embodiment, and FIG. FIG. 7 is a schematic plan view showing the structure of the pixel of Example 2 taken along the line BB ′ of FIG. 5A to 5C, the pixel circuit in the element substrate 10 is not shown. As a method for forming a pixel circuit including the TFT 30, the storage capacitor 16, and wirings connected to these, a known method can be adopted.

Example 1
As illustrated in FIG. 4, the pixel P according to the first embodiment includes a TFT 30 provided for each pixel P on the element substrate 10. The TFT 30 has a semiconductor layer 30a having an LDD (Lightly Doped Drain) structure made of, for example, a polycrystalline silicon film. The semiconductor layer 30a is covered with a gate insulating film 11 made of, for example, silicon oxide, and a gate electrode 30g is provided at a position facing the channel region through the gate insulating film 11. The gate electrode 30g is provided by using a part of the scanning line 3a made of a low resistance wiring material such as aluminum or polysilicon.
A first interlayer insulating film 12 made of, for example, silicon oxide or nitride is provided so as to cover the gate electrode 30 g and the gate insulating film 11. The first interlayer insulating film 12 is provided with contact holes at positions corresponding to the source region 30s and the drain region 30d of the semiconductor layer 30a, and is formed on the first interlayer insulating film 12 so as to fill the contact holes. A source electrode 31 and a drain electrode 32 are formed by patterning the low-resistance wiring material. The source electrode 31 is patterned so as to be electrically connected to the data line 6a.
A second interlayer insulating film 13 made of silicon oxide or nitride is provided so as to cover the source electrode 31 and the drain electrode 32 and the first interlayer insulating film 12. A light shielding film 80 is provided on the second interlayer insulating film 13 at a position overlapping the TFT 30 in a plan view. The light shielding film 80 provided for each TFT 30 on the element substrate 10 constitutes a part of the non-opening portion described above.
A third interlayer insulating film 14 made of silicon oxide or nitride is provided so as to cover the light shielding film 80 and the second interlayer insulating film 13. A pixel electrode 15 is provided for each pixel P on the third interlayer insulating film 14. The pixel electrode 15 is formed using a transparent conductive film such as ITO. The pixel electrode 15 and the drain electrode 32 of the TFT 30 are electrically connected by a contact hole (not shown) provided in the second interlayer insulating film 13 and the third interlayer insulating film 14. The pixel electrode 15 is formed so as to overlap the opening shown in FIG. 3 in a plan view and have a larger area than the opening. In this embodiment, the outer edge portion of the pixel electrode 15 is thicker than the other portions. Therefore, the surface of the pixel electrode 15 facing the liquid crystal layer 50 is not flat and has irregularities on the outer edge side. The uneven sidewall is covered with an insulating film 17.

An alignment film 18 is provided on at least the surface of the pixel electrode 15 facing the liquid crystal layer 50 and the surface of the third interlayer insulating film 14 not covered with the insulating film 17. As described above, the alignment film 18 is formed by depositing silicon oxide as an inorganic material using a vapor phase growth method, and is formed of a columnar body (column) 18a of silicon oxide grown in an oblique direction with respect to the film formation surface. It consists of a set. The inclination angle of the column 18a with respect to the film formation surface is close to the inclination angle of the substrate with respect to the inorganic material emission source in the vapor phase growth method.
In FIG. 4, for the sake of explanation, the column 18a is shown as being large enough to be visually recognized, and spaced from the film formation surface. However, in actuality, the column 18a is very small, and it is closely packed with almost no gap. Growing. When the alignment film 18 is formed using the vapor phase growth method, the column 18a is not easily formed on the uneven side wall portion on the side that tends to be a shadow with respect to the emission source. In Example 1, since the uneven side wall portion is covered with the insulating film 17, the pixel electrode 15 and the liquid crystal layer 50 are not in direct contact with each other.

  A light shielding film 21 is first provided on the side of the counter substrate 20 facing the liquid crystal layer 50, and an interlayer film layer 22 and a common electrode 23 are sequentially formed so as to cover the light shielding film 21. As described above, the light shielding film 21 is provided in a frame shape so as to surround the display region E in the counter substrate 20, and is provided in a lattice shape or a stripe shape so as to constitute a non-opening portion. Therefore, the common electrode 23 covering the interlayer film layer 22 provided so as to overlap the light shielding film 21 is convex toward the liquid crystal layer 50 in the non-opening portion other than the opening portion 21a of the light shielding film 21 (hereinafter, the common electrode 23). It is called a convex part. That is, unevenness is generated on the side of the common electrode 23 facing the liquid crystal layer 50. The side wall portion of the unevenness is also covered with the insulating film 25 similarly to the pixel electrode 15. On the surface of the common electrode 23 facing the liquid crystal layer 50, an alignment film 24 made of a set of columnar bodies (columns) 24a formed by the vapor phase growth method is provided. When the alignment film 24 is formed by using the vapor phase growth method, the column 24a is hardly formed on the side wall portion of the unevenness on the side that tends to be a shadow with respect to the emission source. Since the surface of the common electrode 23 is covered with the insulating film 25 and the column 24 a, it does not directly touch the liquid crystal layer 50.

  On the surfaces of the alignment films 18 and 24, the liquid crystal molecules having negative dielectric anisotropy are substantially vertically aligned with a pretilt applied.

  The liquid crystal molecules having negative dielectric anisotropy that are initially substantially vertically aligned are arranged in a direction orthogonal to the direction of the electric field generated between the pixel electrode 15 and the common electrode 23. However, when a horizontal electric field is generated between the adjacent pixel electrodes 15, the arrangement of the liquid crystal molecules is disturbed due to the influence, which may cause light leakage. In the first embodiment, the element substrate 10 and the counter substrate 20 are disposed to face each other with the liquid crystal layer 50 interposed therebetween so that the outer edge portion of the adjacent pixel electrode 15 and the convex portion of the common electrode 23 overlap each other. Therefore, the thickness of the liquid crystal layer 50 between the outer edge portion of the pixel electrode 15 and the convex portion of the common electrode 23 is thinner than other portions. Therefore, since the electric field strength generated between the outer edge portion of the pixel electrode 15 and the convex portion of the common electrode 23 is higher than that of other portions, liquid crystal molecules are generated even if a horizontal electric field is generated between the adjacent pixel electrodes 15. The above arrangement is not easily disturbed.

  Further, the surfaces of the pixel electrode 15 and the common electrode 23 facing the liquid crystal layer 50 are covered with insulating films 17 and 25 and alignment films 18 and 24, respectively. Therefore, the electric field applied to the liquid crystal layer 50 is not inhibited as compared with the case where the insulating films 17 and 25 are provided over the entire surface of each electrode. In other words, the drive voltage does not increase even if the insulating films 17 and 25 are provided. In addition, since each electrode does not directly touch the liquid crystal layer 50, it is difficult for the charge given between the two electrodes during driving to be released to the liquid crystal layer 50. That is, fluctuations in potential (for example, optimal LCCOM between both electrodes; common potential) due to the discharge of charge are suppressed for a long period of time, and high reliability and stable optical characteristics are realized.

As a manufacturing method of the liquid crystal device 100 of Example 1 as described above, as shown in FIG. 5A, on the element substrate 10, the pixel has a convex portion 15 a having a thicker outer edge portion than others. The electrode 15 is formed (electrode formation process). Such a pixel electrode 15 can be formed by patterning a transparent conductive film such as ITO to form a planar shape and then etching the portions other than the convex portions 15a to reduce the film thickness, A method of selectively forming a transparent conductive film on a portion corresponding to the portion 15a can be mentioned. The method is not limited to such a method, and the surface of the underlying third interlayer insulating film 14 on which the pixel electrode 15 is formed is partially convex, and a transparent conductive film is formed thereon and patterned. Can also be adopted.
Then, an insulating film 17a is formed so as to cover the surface of the element substrate 10 on which the pixel electrode 15 is formed (insulating film forming step). As a method of forming the insulating film 17a, a sputtering method or a vapor deposition method can be used.

  Next, as shown in FIG. 5B, the insulating film 17a on the pixel electrode 15 is removed so that at least the surface of the pixel electrode 15 facing the liquid crystal layer 50 is exposed in the formed insulating film 17a. (Insulating film removing step). As a removing method, a dry etching method capable of controlling etching in the depth direction is preferable. As a result, the insulating film 17 is formed to expose the surface of the pixel electrode 15 and a part between the adjacent pixel electrodes 15 and to cover the side wall portion of the convex portion 15a.

  Then, as shown in FIG. 5C, an alignment film 18 is formed on the surface of the element substrate 10 on which the pixel electrode 15 is formed. The alignment film 18 is formed by depositing an inorganic material by vapor deposition. For example, if oblique vapor deposition is used as the vapor phase growth method, vapor deposition is performed by arranging the element substrate 10 obliquely with respect to a vapor deposition source for evaporating silicon oxide. At that time, for example, as shown in FIG. 3, the vapor deposition direction is directed from the upper right to the lower left indicated by the solid line arrows with respect to the pixels P (pixel electrodes 15) arranged in a matrix in the X direction and the Y direction. The oblique deposition is performed from the azimuth angle direction of about 45 degrees. As a result, an aggregate of columns 18a grown in the vapor deposition direction on the film formation surface is obtained.

  As a method for forming the light shielding film 21, the interlayer film layer 22, and the common electrode 23 in the counter substrate 20, a known method can be adopted. Further, as a method for forming the insulating film 25 covering the side wall portion of the convex portion of the common electrode 23, the same method as the method for forming the insulating film 17 in the pixel electrode 15 can be employed. Further, as the method for forming the alignment film 24 on the counter substrate 20, as in the case of the element substrate 10, the oblique deposition method can be used as the vapor phase growth method. For example, as shown in FIG. 3, the vapor deposition direction in this case is an azimuth angle of about 45 degrees from the lower left to the upper right indicated by the dashed arrow with respect to the pixels P arranged in a matrix in the X direction and the Y direction. Diagonal deposition from the direction. That is, as shown in FIG. 4, when the element substrate 10 and the counter substrate 20 are arranged to face each other, oblique vapor deposition is performed so that the growth directions of the column 18a and the column 24a coincide.

  According to the manufacturing method of the liquid crystal device 100 of Example 1 described above, liquid crystal molecules having negative dielectric anisotropy are formed without directly touching the liquid crystal layer 50 with the uneven pixel electrode 15 or the common electrode 23. The liquid crystal device 100 including the alignment films 18 and 24 that are substantially vertically aligned without unevenness can be manufactured.

(Example 2)
6 is a schematic plan view showing the configuration of the pixel of Example 2, and FIG. 7 is a schematic cross-sectional view showing the structure of the pixel taken along line BB ′ of FIG. The configuration and structure of the pixel having irregularities on the electrode surface can be applied not only to the transmissive pixel of the first embodiment but also to the reflective pixel of the second embodiment. In addition, the same code | symbol is attached | subjected about the same structure as Example 1, and detailed description is abbreviate | omitted.

  As shown in FIG. 6, the pixel PB in the reflective liquid crystal device 100 includes a data line 6a and a scanning line 3a that are orthogonal to each other, and a capacitor line 3b that is arranged in parallel to the scanning line 3a. The capacitance line 3b is provided with an expansion portion 3c whose width is expanded in the pixel PB and functions as one capacitance electrode. A relay electrode 16a that functions as the other capacitor electrode is provided so as to overlap the capacitor line 3b including the extended portion 3c in a plane. A dielectric layer is sandwiched between the extended portion 3c connected to the capacitor line 3b and the relay electrode 16a disposed so as to constitute the storage capacitor 16.

  The TFT 30 is provided near the intersection of the data line 6a and the scanning line 3a. In addition, the elongated semiconductor layer 30a intersects the scanning line 3a, the source region 30s of the semiconductor layer 30a overlaps the protruding portion 6b that protrudes in the pixel PB from the data line 6a, and the drain region 30d side of the semiconductor layer 30a is It arrange | positions so that it may overlap with the relay electrode 16a.

  The pixel electrode 15B is made of a metal material such as Al (aluminum) or an alloy thereof and has light reflectivity. In addition, the data line 6a, the scanning line 3a, the capacitor line 3b, the relay electrode 16a, and the TFT 30 are arranged so as to overlap in a plane.

  As shown in FIG. 7, the TFT 30 includes a semiconductor layer 30 a having an LDD structure formed of, for example, a polycrystalline silicon film formed on the element substrate 10. The semiconductor layer 30a is covered with a gate insulating film 11 made of, for example, silicon oxide, and a scanning line 3a is provided on the gate insulating film 11 so as to overlap the channel region of the semiconductor layer 30a. That is, like the first embodiment, the TFT 30 is a thin film transistor having a top gate structure in which a part of the scanning line 3a becomes the gate electrode 30g.

  A first interlayer insulating film 12 is provided so as to cover the scanning line 3 a, and the capacitor line 3 b and its extended portion 3 c are provided on the first interlayer insulating film 12. A second interlayer insulating film 13 is provided so as to cover the capacitor line 3b and the extended portion 3c, and the data line 6a, the protruding portion 6b, and the relay electrode 16a are formed on the second interlayer insulating film 13 by patterning. The second interlayer insulating film 13 functions as a dielectric layer in the storage capacitor 16.

  A third interlayer insulating film 14 is provided so as to cover the data line 6a, the protruding portion 6b, and the relay electrode 16a, and a pixel electrode 15B is provided on the third interlayer insulating film 14.

  The scanning line 3a, the capacitor line 3b, the data line 6a, and the relay electrode 16a are all made of a low resistance wiring material such as Al or an alloy thereof, and the protruding portion 6b of the data line 6a is formed of the gate insulating film 11 and the first interlayer insulating film. The semiconductor layer 30a is connected to the source region 30s through a contact hole 13a provided so as to penetrate the film 12 and the second interlayer insulating film 13.

  The relay electrode 16a is connected to the drain region 30d of the semiconductor layer 30a through a contact hole 13b provided so as to penetrate the gate insulating film 11, the first interlayer insulating film 12, and the second interlayer insulating film 13.

  The relay electrode 16a is connected to the pixel electrode 15B through a contact hole 14a in which an opening provided so as to penetrate the third interlayer insulating film 14 is filled with a material for forming the pixel electrode 15B.

  In the reflective liquid crystal device 100 of Example 2, since the pixel electrode 15B has reflectivity, elements of the pixel circuit such as the TFT 30 and the storage capacitor 16 can be formed below the pixel electrode 15B. On the other hand, the surface of the pixel electrode 15B has unevenness caused by the pixel circuit provided in the lower layer. An insulating film 17 is formed on the uneven sidewall as in the first embodiment. Therefore, even if the alignment film 18 is formed on the surface of the element substrate 10 provided with the pixel electrode 15B by using the vapor phase growth method, the insulating film is not formed on the shaded portion where the column 18a is difficult to grow on the uneven side wall portion. Since 17 is formed, the surface of the pixel electrode 15B is prevented from directly touching the liquid crystal layer 50.

  According to the second embodiment, since the surface of the pixel electrode 15B does not directly touch the liquid crystal layer 50, the reflective liquid crystal device 100 that provides high reliability and stable optical characteristics as in the first embodiment is provided. be able to.

  In the first and second embodiments, the insulating films 17 and 25 are formed at portions where the uneven step on the electrode is at least 200 nm in view of the degree of shadow of the vapor phase growth method in forming the alignment films 18 and 24. It is preferable to form so as to cover the side wall portion. In other words, unevenness with a step of less than 200 nm can be ignored.

<Electronic equipment>
FIG. 8 is a schematic diagram illustrating a configuration of a projection display device as an electronic apparatus. As shown in FIG. 8, a projection display apparatus 1000 as an electronic apparatus according to this embodiment includes a polarized illumination apparatus 1100 arranged along the system optical axis L, and two dichroic mirrors 1104 and 1105 as light separation elements. Three reflection mirrors 1106, 1107, 1108, five relay lenses 1201, 1202, 1203, 1204, 1205, three transmissive liquid crystal light valves 1210, 1220, 1230 as light modulation means, and a light combining element As a cross dichroic prism 1206 and a projection lens 1207.

  The polarized light illumination device 1100 is generally configured by a lamp unit 1101 as a light source composed of a white light source such as an ultra-high pressure mercury lamp or a halogen lamp, an integrator lens 1102, and a polarization conversion element 1103.

  The dichroic mirror 1104 reflects red light (R) and transmits green light (G) and blue light (B) among the polarized light beams emitted from the polarization illumination device 1100. Another dichroic mirror 1105 reflects the green light (G) transmitted through the dichroic mirror 1104 and transmits the blue light (B).

The red light (R) reflected by the dichroic mirror 1104 is reflected by the reflection mirror 1106 and then enters the liquid crystal light valve 1210 via the relay lens 1205.
Green light (G) reflected by the dichroic mirror 1105 enters the liquid crystal light valve 1220 via the relay lens 1204.
The blue light (B) transmitted through the dichroic mirror 1105 enters the liquid crystal light valve 1230 via a light guide system including three relay lenses 1201, 1202, 1203 and two reflection mirrors 1107, 1108.

  The liquid crystal light valves 1210, 1220, and 1230 are disposed to face the incident surfaces of the cross dichroic prism 1206 for each color light. The color light incident on the liquid crystal light valves 1210, 1220, and 1230 is modulated based on video information (video signal) and emitted toward the cross dichroic prism 1206. 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 thereof. The three color lights are synthesized by these dielectric multilayer films, and the light representing the color image is synthesized. The synthesized light is projected on the screen 1300 by the projection lens 1207 which is a projection optical system, and the image is enlarged and displayed.

  The liquid crystal light valve 1210 is the one to which the liquid crystal device 100 described above is applied. The liquid crystal device 100 is arranged with a gap between a pair of polarizing elements arranged in crossed Nicols on the incident side and the emission side of colored light. The same applies to the other liquid crystal light valves 1220 and 1230.

  According to such a projection type display device 1000, the liquid crystal device 100 capable of obtaining high reliability and stable optical characteristics is provided, and high display quality is realized. In addition, as the liquid crystal light valves 1210, 1220, and 1230, the projection display device 1000 can be configured by using the reflective liquid crystal device 100 shown in Embodiment 2 as well as the transmissive type.

  Various modifications other than the above embodiment are conceivable. Hereinafter, a modification will be described.

  (Modification 1) In the transmissive liquid crystal device 100 of the first embodiment, the portion where the pixel circuit elements such as the TFT 30 and the storage capacitor 16 are arranged is not limited to the non-opening portion of the pixel P. For example, the size of the pixel P may be high definition, and a part of the pixel circuit may be disposed so as to protrude from the opening. In other words, at least a part of the unevenness on the pixel electrode 15 caused by the pixel circuit may be arranged in the opening of the pixel P.

  (Modification 2) In the liquid crystal device 100, the configuration in which the side wall portion of the unevenness on the electrode is covered with the insulating film 17 does not have to be applied to both the pixel electrode 15 of the element substrate 10 and the common electrode 23 of the counter substrate 20. Good. In other words, if an insulating film is provided so as to correspond to the unevenness of the electrode in either one, a corresponding effect can be obtained.

  (Modification 3) In the liquid crystal device 100, the convex portion on the common electrode 23 side is not limited to the one formed by providing the light shielding film 21 and the interlayer film layer 22. For example, the light shielding film 21 may be eliminated, and the common electrode 23 may be formed so as to cover the interlayer film layer 22 with irregularities.

(Modification 4) The shape of the pixel electrode 15 that covers the side wall portion with the insulating film 17 is not limited to that having irregularities on the surface of the pixel electrode 15. FIG. 9 is a schematic cross-sectional view illustrating a pixel structure of a liquid crystal device according to a modification. The same components as those of the liquid crystal device 100 are denoted by the same reference numerals, and detailed description thereof is omitted.
For example, as illustrated in FIG. 9, the liquid crystal device 150 according to the modification includes a plurality of pixel electrodes 15 </ b> C on the element substrate 10. The pixel electrode 15C has a flat surface, and an insulating film 17 is provided so as to cover the side wall portion on the outer peripheral side. As described above, the alignment film 18 is an aggregate of columns 18a obtained by, for example, oblique deposition of silicon oxide, and the column 18a hardly grows on the side wall portion of the pixel electrode 15C that becomes a shadow during oblique deposition. , It grows on the side wall portion of the portion that does not become a shadow. Since all the side wall portions are covered with the insulating film 17, it is possible to prevent the pixel electrode 15 </ b> C from coming into direct contact with the liquid crystal layer 50. That is, the liquid crystal device 150 according to the modified example can provide high reliability and stable optical characteristics as in the liquid crystal device 100 according to the first embodiment.

  (Modification 5) The electronic apparatus to which the transmissive or reflective liquid crystal device 100 is applied is not limited to the projection display device 1000. For example, a projection-type HUD (head-up display), a direct-view HMD (head-mounted display), an electronic book, a personal computer, a digital still camera, an LCD TV, a viewfinder-type or monitor-direct-view video recorder, car navigation It can be suitably used as a display unit of an information terminal device such as a system, electronic notebook, or POS.

  DESCRIPTION OF SYMBOLS 10 ... Element board | substrate as one board | substrate, 15, 15B, 15C ... Pixel electrode as an electrode, 17 ... Insulating film, 18 ... Alignment film as an inorganic alignment film, 20 ... Opposite board | substrate as another board | substrate, 21 ... Light-shielding Membrane, 22 ... interlayer film layer, 23 ... common electrode as electrode, 24 ... alignment film as inorganic alignment film, 25 ... insulating film, 50 ... liquid crystal layer, 100, 150 ... liquid crystal device as electro-optical device, 1000 ... A projection display device as an electronic device.

Claims (8)

An electro-optical device in which a liquid crystal layer having negative dielectric anisotropy is sandwiched between a pair of substrates,
An insulating film covering at least a side wall portion of an electrode provided on at least one of the pair of substrates;
And an inorganic alignment film covering a surface of the at least one substrate including the electrode and the insulating film. The electrode has irregularities on the surface,
The electro-optical device according to claim 1, wherein the insulating film is further provided to cover a side wall portion of the unevenness. The one substrate has a pixel circuit, a plurality of pixel electrodes as the electrodes, and the inorganic alignment film covering the pixel electrodes,
The other substrate of the pair of substrates includes a common electrode facing the plurality of pixel electrodes with the liquid crystal layer interposed therebetween, and the inorganic alignment film covering the common electrode,
The electro-optical device according to claim 2, wherein the unevenness on the pixel electrode corresponds to a position where the pixel circuit is provided. The one substrate has a plurality of pixel electrodes as the electrodes and the inorganic alignment film covering the pixel electrodes,
The other substrate of the pair of substrates includes a common electrode facing the plurality of pixel electrodes with the liquid crystal layer interposed therebetween, and the inorganic alignment film covering the common electrode,
The electro-optical device according to claim 2, wherein the unevenness on the pixel electrode is provided at an outer edge portion of the pixel electrode. The one substrate has a plurality of pixel electrodes as the electrodes and the inorganic alignment film covering the pixel electrodes,
The other substrate of the pair of substrates is a light shielding film that partitions pixels in a plane, an interlayer film layer that covers the light shielding film, and an electrode that covers the interlayer film layer and faces the plurality of pixel electrodes. Having a common electrode and the inorganic alignment film covering the common electrode;
The electro-optical device according to claim 2, wherein the unevenness on the common electrode corresponds to a position where the light shielding film is provided. A method of manufacturing an electro-optical device in which a liquid crystal layer having negative dielectric anisotropy is sandwiched between a pair of substrates,
Forming an electrode on at least one of the pair of substrates; and
An insulating film forming step of forming an insulating film covering at least a side wall portion of the electrode;
An alignment film forming step of forming an inorganic alignment film covering the surface of the electrode including the insulating film using a vapor phase growth method,
The insulating film forming step includes a step of forming the insulating film so as to cover the electrode, and a step of removing the insulating film on the electrode so that a surface of the electrode facing the liquid crystal layer is exposed. A method for manufacturing an electro-optical device.   In the insulating film forming step, the insulating film is left on at least a side wall portion of the unevenness of the electrode, and the insulating film on the electrode is removed so that a surface of the electrode facing the liquid crystal layer is exposed. A method for manufacturing an electro-optical device according to claim 6.   An electronic apparatus comprising the electro-optical device according to claim 1.

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