JP2013068874A - Liquid crystal device, method for manufacturing liquid crystal device, and electronic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid crystal device having an inorganic alignment layer efficiently formed by oblique vapor deposition and showing stable optical characteristics as well as display qualities, a method for manufacturing the liquid crystal device, and electronic equipment including the liquid crystal device.SOLUTION: A liquid crystal device 100 in an embodiment includes a device substrate 10 as a first substrate, a counter substrate 20 as a second substrate, a liquid crystal layer 50 comprising liquid crystal molecules having negative dielectric anisotropy and sandwiched by the device substrate 10 and the counter substrate 20, a base insulating film 11 disposed between the device substrate 10 and the liquid crystal layer 50 and having a plurality of recesses 11a, a pixel electrode 15 as an electrode disposed between the base insulating film 11 and the liquid crystal layer 50 and having a recessed surface corresponding to the base insulating film 11, and an alignment layer 18 as an inorganic alignment layer formed by oblique vapor deposition on the recessed surface.

Description

  The present invention relates to a liquid crystal device, a method for manufacturing the liquid crystal device, and an electronic apparatus including the liquid crystal device.

  As the liquid crystal device, liquid crystal is sealed in a gap formed by bonding a pair of substrates on which an inorganic alignment film is formed through a sealing material, and there are innumerable recesses for arranging liquid crystal molecules on the surface of the inorganic alignment film. A liquid crystal display element formed in (1) is disclosed (Patent Document 1).

  According to Patent Document 1, the inorganic alignment film etches the surface of the inorganic film to form innumerable recesses on the surface, and vertically aligns liquid crystal molecules along the vertical wall surface of the recess.

  On the other hand, a method is disclosed in which an electrode made of ITO for applying a driving voltage to a liquid crystal is formed by film formation at room temperature to reduce unevenness generated on the electrode surface (Patent Document 2). According to this, the unevenness on the inorganic alignment film formed so as to cover the electrode surface can be reduced, and the occurrence of poor alignment of liquid crystal due to the unevenness can be reduced. The inorganic alignment film disclosed in Patent Document 2 is formed by oblique deposition of an inorganic material such as silicon oxide.

JP 2006-284722 A JP 2008-216943 A

However, in the liquid crystal display element of Patent Document 1 described above, it is difficult to vertically align liquid crystal molecules by giving a predetermined pretilt to the surface on which the recesses are formed, and an electric field is applied when a driving voltage is applied to the liquid crystal display element. It is difficult to control the direction in which the liquid crystal molecules are inclined to the direction. Therefore, there is a problem that optical characteristics such as stable viewing angle characteristics cannot be realized.
Further, as described in Patent Document 2, if the unevenness of the electrode surface on which the inorganic alignment film is formed is reduced, the liquid crystal can be given a predetermined pretilt unless the film formation rate during oblique deposition is slow compared to the case where the unevenness is provided. There is a problem that it is difficult to form an inorganic alignment film for vertically aligning molecules, that is, productivity is 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 A liquid crystal device according to this application example includes a first substrate, a second substrate, and a liquid crystal having negative dielectric anisotropy sandwiched between the first substrate and the second substrate. A liquid crystal layer made of molecules; a base insulating film provided between the first substrate and the liquid crystal layer, having a plurality of recesses; and provided between the base insulating film and the liquid crystal layer; An electrode having a concave surface corresponding to the insulating film and an inorganic alignment film formed by oblique deposition on the concave surface are provided.

According to this configuration, since the electrode on which the inorganic alignment film is formed has a concave surface corresponding to the underlying insulating film, the liquid crystal molecules having negative dielectric anisotropy are given a predetermined pretilt to achieve vertical alignment. The inorganic alignment film to be formed can be efficiently obtained by oblique deposition. That is, a liquid crystal device having stable optical characteristics can be provided with high productivity.
In addition, compared to the case where the electrode itself is processed to form a plurality of recesses on the surface, a plurality of recesses are formed in the base insulating film of the electrode. A recess is easily formed.

  Application Example 2 Another liquid crystal device according to this application example has a negative dielectric anisotropy sandwiched between a first substrate, a second substrate, and the first substrate and the second substrate. A liquid crystal layer comprising liquid crystal molecules, an electrode provided between the first substrate and the liquid crystal layer, and a recess surface provided between the electrode and the liquid crystal layer and having a plurality of recesses. And an inorganic alignment film formed by oblique vapor deposition on the surface of the recess.

According to this configuration, a plurality of recesses are formed on the surface of the insulating film on which the inorganic alignment film is formed to form the recess surface, thereby giving a predetermined pretilt to liquid crystal molecules having negative dielectric anisotropy. An inorganic alignment film that is vertically aligned can be efficiently obtained by oblique deposition. That is, a liquid crystal device having stable optical characteristics can be provided with high productivity.
In addition, since a plurality of recesses are formed in the insulating film covering the electrode, the liquid crystal molecules having negative dielectric anisotropy are given a predetermined pretilt between the electrode and the liquid crystal layer, regardless of the thickness of the electrode. An inorganic alignment film to be aligned can be efficiently obtained on the insulating film by oblique vapor deposition.

Application Example 3 In the liquid crystal device according to the application example described above, it is preferable that the roughness Ra of the concave surface is 5 nm or more and 20 nm or less.
According to this configuration, since the inorganic alignment film is formed by oblique deposition on the surface of the recess having a roughness Ra of 5 nm or more and 20 nm or less, the roughness Ra on the surface of the inorganic alignment film after the formation is substantially equal. Since the roughness Ra, that is, the unevenness on the surface of the inorganic alignment film is relatively small with respect to the film thickness of the inorganic alignment film, the occurrence of poor alignment of liquid crystal molecules due to the unevenness hardly occurs. Accordingly, it is possible to efficiently obtain an inorganic alignment film that vertically aligns liquid crystal molecules having negative dielectric anisotropy by giving a predetermined pretilt, and provides a liquid crystal device having more stable optical characteristics. it can.

Application Example 4 In the liquid crystal device according to the application example, it is preferable that the electrode is a pixel electrode, and the film thickness of the pixel electrode is 10 nm or more and 50 nm or less.
According to this configuration, since the thickness of the pixel electrode is 10 nm or more and 50 nm or less, for example, even if a plurality of concave portions of the base insulating film is covered with the pixel electrode, the surface does not become flat, and the surface of the pixel electrode is not grounded. A recess surface reflecting a plurality of recesses of the insulating film can be easily formed.

  Application Example 5 A method for manufacturing a liquid crystal device according to this application example is a method for manufacturing a liquid crystal device in which a liquid crystal layer composed of liquid crystal molecules having negative dielectric anisotropy is sandwiched between a first substrate and a second substrate. A step of forming a base insulating film on a side of the first substrate facing the liquid crystal layer, and a step of forming a plurality of concave portions on the surface of the base insulating film on the side facing the liquid crystal layer. A step of forming an electrode having a concave surface corresponding to the base insulating film by forming a conductive film covering the base insulating film and patterning the conductive film; and oblique deposition on the concave surface And an alignment film forming step of forming an inorganic alignment film.

According to this method, by forming a plurality of recesses in the base insulating film of the electrode in the recess forming step, the surface of the recess reflecting the plurality of recesses of the base insulating film is formed on the surface of the electrode in the electrode forming step. The Therefore, in the alignment film forming step, an inorganic alignment film can be efficiently formed by oblique deposition by vertically applying the liquid crystal molecules having negative dielectric anisotropy to the concave surface of the electrode by giving a predetermined pretilt. That is, a liquid crystal device having stable optical characteristics can be manufactured with high productivity.
In addition, compared with the case where the electrode itself is processed to form a plurality of recesses on the surface, the recess forming step forms a plurality of recesses in the base insulating film of the electrode, so even if the electrode thickness is reduced A recess can be easily formed on the surface.

  Application Example 6 Another method of manufacturing a liquid crystal device according to this application example is a liquid crystal device in which a liquid crystal layer composed of liquid crystal molecules having negative dielectric anisotropy is sandwiched between a first substrate and a second substrate. An electrode forming step of forming an electrode on a side of the first substrate facing the liquid crystal layer, a step of forming an insulating film covering the electrode, and a surface of the insulating film facing the liquid crystal layer. A recess forming step of forming a plurality of recesses on the surface on the surface to form the recess surface, and an alignment film forming step of forming an inorganic alignment film on the recess surface by oblique vapor deposition. .

According to this method, by forming a plurality of recesses in the insulating film covering the electrodes in the recess forming step and forming the recess surface, in the alignment film forming step, negative dielectric anisotropy is formed on the recess surface of the insulating film. Inorganic alignment films that vertically align liquid crystal molecules having a predetermined pretilt can be efficiently formed by oblique deposition. That is, a liquid crystal device having stable optical characteristics can be manufactured with high productivity.
In addition, according to this method, an inorganic alignment film that vertically aligns liquid crystal molecules having negative dielectric anisotropy by applying a predetermined pretilt between the electrode and the liquid crystal layer regardless of the thickness of the electrode. It can be formed efficiently by oblique deposition.

Application Example 7 In the method of manufacturing a liquid crystal device according to the application example, it is preferable that in the electrode formation step, the pixel electrode as the electrode is formed so as to have a thickness of 10 nm to 50 nm.
According to this method, the pixel electrode is formed so that the thickness thereof is 10 nm or more and 50 nm or less. Therefore, for example, the surface of the recess that reflects the plurality of recesses of the base insulating film is reliably formed on the surface of the pixel electrode. can do.

Application Example 8 In the method of manufacturing a liquid crystal device according to the application example, it is preferable that the recess forming step forms the plurality of recesses so that roughness Ra of the surface of the recess is 5 nm or more and 20 nm or less.
According to this method, in the alignment film forming step, since the inorganic alignment film is formed by oblique deposition on the surface having a roughness Ra of 5 nm to 20 nm, the roughness Ra on the surface of the inorganic alignment film after the formation is substantially equal. . Since the roughness Ra, that is, the unevenness on the surface of the inorganic alignment film is relatively small, occurrence of poor alignment of liquid crystal molecules due to the unevenness is reduced. That is, a liquid crystal device having more stable optical characteristics can be manufactured.

Application Example 9 An electronic apparatus according to this application example includes the liquid crystal device according to the application example described above.
According to this configuration, an electronic apparatus having stable optical characteristics and high cost performance can be provided.

(A) is a schematic plan view which shows the structure of a liquid crystal device, (b) is a schematic sectional drawing in alignment with the H-H 'line | wire of the liquid crystal device shown to (a). FIG. 3 is an equivalent circuit diagram illustrating an electrical configuration of the liquid crystal device. FIG. 4 is a schematic cross-sectional view illustrating a structure of a pixel of a liquid crystal device. (A) And (b) is a schematic plan view which shows arrangement | positioning of the recessed part in the formation surface of an inorganic alignment film. Schematic which shows an oblique vapor deposition apparatus. The table | surface which shows the inorganic alignment film formation conditions of an Example, the comparative example 1, and the comparative example 2, and evaluation of the display quality and productivity in a liquid crystal device. 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, for example, 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 each other and a part is arranged via another component.

(First embodiment)
In this embodiment, an active matrix type liquid crystal device including a thin film transistor 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, the liquid crystal device of this embodiment will be described with reference to FIGS. 1A is a schematic plan view showing the configuration of the liquid crystal device, and FIG. 1B is a schematic cross-sectional view taken along the line HH ′ of the liquid crystal device shown in FIG. FIG. 2 is an equivalent circuit diagram showing an electrical configuration of the liquid crystal device.

  As shown in FIGS. 1A and 1B, a liquid crystal device 100 according to the present embodiment includes an element substrate 10 as a first substrate and a counter substrate 20 as a second substrate, which are opposed to each other, and a pair of these. And a liquid crystal layer 50 sandwiched between the substrates. The element substrate 10 and the counter substrate 20 are made of, for example, a transparent quartz substrate or glass substrate.

  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. As 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.

  On the inner side of the sealing material 40 arranged in a frame shape, a parting portion 21 is provided in the same frame shape. The parting part 21 is made of, for example, a light-shielding metal or metal oxide, and the inside of the parting part 21 is a pixel region E having a plurality of pixels P. The pixel region E may include dummy pixels arranged so as to surround the plurality of pixels P in addition to the plurality of pixels P contributing to display. Although not shown in FIG. 1, a light-shielding portion that divides a plurality of pixels P in a plane in the pixel region E is provided.

  A data line driving circuit 101 is provided between the sealing material 40 along one side of the element substrate 10 and the 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. Note that 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 sealant 40 between the data line driving circuit 101 and the pixel region E.

  As shown in FIG. 1B, on the surface of the element substrate 10 on the liquid crystal layer 50 side, a light-transmissive pixel electrode 15 provided for each pixel P and a thin film transistor (Thin Film Transistor, (Hereinafter referred to as TFT) 30, a signal wiring, and an alignment film 18 covering these are formed. In addition, a light shielding structure is employed that prevents light from entering the semiconductor layer in the TFT 30 to make the switching operation unstable.

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

  As shown in FIG. 1A, the parting portion 21 is provided in a frame shape at a position where it overlaps the scanning line driving circuit 102 and the inspection circuit 103 in a plane. 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 pixel region E to ensure high contrast in the display of the pixel region E.

  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 parting portion 21 with light transmittance. Examples of a method for forming such an interlayer film layer 22 include a method of forming a film using a plasma CVD method or the like.

  The common electrode 23 is made of, for example, a transparent conductive film such as ITO (Indium Tin Oxide), covers the interlayer film layer 22, and as shown in FIG. 1 (a), the vertical conductive portions 106 provided at the four corners of the counter substrate 20. Thus, the wiring is electrically connected to the wiring on the element substrate 10 side.

  The alignment film 18 that covers the pixel electrode 15 and the alignment film 24 that covers the common electrode 23 are set based on the optical design of the liquid crystal device 100. In this embodiment, an inorganic material such as SiOx (silicon oxide) is formed into a film by oblique vapor deposition from a predetermined direction with respect to the substrate surface, and the liquid crystal molecules having negative dielectric anisotropy are aligned along the predetermined direction. In addition, an inorganic alignment film that gives a pretilt and is substantially vertically aligned is employed. Specifically, as shown in FIG. 1A, oblique deposition is performed in the element substrate 10 from the deposition direction indicated by the dashed arrow from the upper right to the lower left, and from the lower left to the upper right in the counter substrate 20. Diagonal vapor deposition is performed from the vapor deposition direction indicated by the solid arrows. The azimuth angle θa formed by the reference Y direction and the vapor deposition direction is 45 °. In other words, the element substrate 10 and the counter substrate 20 are obliquely vapor-deposited from opposite directions, and such an alignment treatment method gives a pretilt along a predetermined direction to liquid crystal molecules, so that uniaxial vertical alignment is performed. It is called processing. A method for aligning liquid crystal molecules by the alignment films 18 and 24 and a method for forming the alignment films 18 and 24 will be described later.

  As shown in FIG. 2, the liquid crystal device 100 is arranged in parallel along the data lines 6 a with a plurality of scanning lines 3 a and a plurality of data lines 6 a as signal lines insulated and orthogonal to each other at least in the pixel region E. Capacitance line 3b. The direction in which the scanning line 3a extends is the X direction, and the direction in which the data line 6a extends is the Y direction.

  A pixel electrode 15, 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. doing.

  The scanning line 3 a is electrically connected to the gate of the TFT 30, and the data line 6 a is electrically connected to the first source / drain region of the TFT 30. The pixel electrode 15 is electrically connected to the second source / drain region 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 line-sequentially 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 supplies the scanning signals SC1 to SCm to the scanning line 3a in a pulse-sequential manner 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 predetermined level of image signals D1 to Dn written to the liquid crystal layer 50 via the pixel electrode 15 is held for a certain period between the pixel electrode 15 and the common electrode 23 arranged to face each other via 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 second source / drain region of the TFT 30 and the capacitor line 3b.

  The storage capacitor 16 has a dielectric layer between the light-shielding first capacitor electrode and the second capacitor electrode. The first capacitor electrode functions as the capacitor line 3b. Further, the capacitor line 3b (first capacitor electrode) is connected to a fixed potential.

  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 transmissive type, and employs a normally black mode optical design in which, for example, 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.

  Next, a detailed structure of the pixel P of the liquid crystal device 100 and a method for manufacturing the liquid crystal device 100, particularly a method for forming the alignment films 18 and 24, will be described with reference to FIGS. 3 is a schematic cross-sectional view showing the structure of the pixel, FIGS. 4A and 4B are schematic plan views showing the arrangement of recesses on the surface on which the inorganic alignment film is formed, and FIG. 5 is a schematic view showing an oblique deposition apparatus. is there. FIG. 3 is a schematic cross-sectional view of the pixel P along a predetermined direction of the uniaxial vertical alignment process described above.

  As shown in FIG. 3, an alignment film 18 and an alignment film 24 obtained by obliquely depositing silicon oxide are formed on the surfaces of the pixel electrode 15 and the common electrode 23 in the liquid crystal device 100. Specifically, the angle θb of the vapor deposition direction with respect to the substrate surface facing the liquid crystal layer 50 is approximately 45 °. By such oblique deposition, silicon oxide crystals grow in the form of columns on the substrate surface in the deposition direction. These columnar crystals are called columns 18a and 24a. The alignment films 18 and 24 are aggregates of such columns 18a and 24a. Further, the angle θc in the growth direction of the columns 18a and 24a with respect to the substrate surface does not necessarily coincide with the angle θb in the vapor deposition direction, and in this case, is approximately 70 °.

  The pretilt angle θp with respect to the normal direction of the substrate of the liquid crystal molecules 50a that are substantially vertically aligned on the surfaces of the alignment films 18 and 24 is about 4 °. Further, the predetermined direction of the pretilt of the liquid crystal molecules 50a viewed from the normal direction of the substrate surface is the same as the planar deposition direction of the oblique deposition in the alignment films 18 and 24 as shown in FIG. is there. The predetermined direction of the uniaxial vertical alignment process is appropriately set based on the optical design conditions of the liquid crystal device 100. In the present embodiment, the predetermined direction intersects at an angle of 45 ° with respect to the transmission axis or absorption axis of the polarizing element arranged in the light incident direction and the light emitting direction.

Next, the configuration of the element substrate 10 will be described in detail. On the surface of the element substrate 10 facing the liquid crystal layer 50, a base insulating film 11, a pixel electrode 15, and an alignment film 18 are sequentially formed.
As the base insulating film 11, for example, an inorganic insulating film in which B (boron) or the like is added to silicon oxide or silicon oxide is used, and a plurality of concave portions 11a are formed on the surface (recess forming step). . A transparent conductive pixel electrode 15 is formed by forming a film of a transparent conductive film such as ITO (Indium Tin Oxide) and patterning the surface on which the plurality of concave portions 11a are formed (electrode formation). Process). As a result, a plurality of recesses 15a corresponding to the plurality of recesses 11a, that is, the recess surfaces in the present invention are also formed on the surface of the pixel electrode 15 on the liquid crystal layer 50 side. Hereinafter, the plurality of recesses 15a formed in the pixel electrode 15 may be collectively referred to as a recess surface 15a.

  The planar shape and arrangement of the plurality of recesses 11a (recesses 15a) are, for example, as shown in FIG. 4A, circular in plan view, and the center of the adjacent recesses 11a (recesses 15a) is a square corner. For example, as shown in FIG. 4 (b), a simple matrix arrangement located in a portion, a delta arrangement in which the centers of adjacent concave portions 11a (concave portions 15a) are located at the vertices of equilateral triangles, and the like can be given. Note that the planar shape and arrangement of the plurality of recesses 11a (recesses 15a) are not limited to this, for example, a plurality of different shapes are arranged at substantially the same density when viewed in units of pixels.

  The recess 11a (recess 15a) has a small size, and the alignment film 18 is efficiently formed by oblique deposition, and the alignment of the liquid crystal molecules 50a is caused by the unevenness generated on the surface of the alignment film 18 on the liquid crystal layer 50 side. In consideration of the possibility of unevenness, the recess 11a is formed so that the roughness Ra (arithmetic mean roughness) of the surface in contact with the pixel electrode 15 is 5 nm or more and 20 nm or less.

(Example)
As an example of the recess 11a, for example, the size is φ500 nm in plan view, the arrangement interval between the adjacent recesses 11a is approximately 1 μm, and the depth is approximately 10 nm. The thickness of the pixel electrode 15 formed on the surface where the concave portion 11 a is formed reflects the visible light transmittance and electric resistance, and the plurality of concave portions 11 a of the base insulating film 11 on the surface of the pixel electrode 15. Therefore, the thickness is set to be 10 nm or more and 50 nm or less. In consideration of the surrounding of the inorganic alignment film (alignment film 18) in the vicinity of the outer periphery of the pixel electrode 15, the pixel electrode 15 is preferably thinner than the inorganic alignment film (alignment film 18). In the example, the thickness of the inorganic alignment film (alignment film 18) was set to 70 nm to 80 nm, and the thickness of the pixel electrode 15 was set to 20 nm.

  The alignment film forming step in the method for manufacturing the liquid crystal device 100 is performed using an oblique deposition apparatus 300 as shown in FIG. The workpiece W in FIG. 5 is a quartz substrate in a wafer shape, for example, in plan view, on which a plurality of element substrates 10 are provided.

  The oblique vapor deposition apparatus 300 includes a chamber 301 capable of reducing the pressure inside, and a vapor deposition source 302 provided at the bottom of the chamber 301. In the vapor deposition source 302, an inorganic material such as silicon oxide constituting the alignment film 18 is mounted as, for example, pellets, which are heated and evaporated under reduced pressure. A plurality of workpieces W can be arranged above the vapor deposition source 302 of the chamber 301. Specifically, the workpiece W is disposed in the chamber 301 such that the deposition surface of the workpiece W is inclined with respect to a normal line toward the deposition source 302. The angle formed by the perpendicular line toward the vapor deposition source 302 and the normal line of the vapor deposition surface is called the elevation angle. Of course, the planar orientation angle θa (45 °; see FIG. 1A) in the vapor deposition direction and the vapor deposition direction angle θb (45 °; see FIG. 3) with respect to the deposition surface are obtained. The workpiece W is arranged with the elevation angle set.

  The inorganic material evaporated from the vapor deposition source 302 reaches the workpiece W and crystallizes. By performing such oblique deposition for a predetermined time, the crystal of the inorganic material grows to become a columnar column 18a (see FIG. 3), and the alignment film 18 that is an aggregate of the column 18a is formed.

  In addition, since the workpiece W is tilted by giving a predetermined elevation angle with respect to the vertical line of the vapor deposition source 302, the angle θb in the vapor deposition direction with respect to the vapor deposition surface decreases depending on the size of the work W, but decreases as the distance from the vapor deposition source 302 increases. Become. In other words, the angle θb in the vapor deposition direction with respect to the workpiece W is not necessarily constant. In order to make the angle θb in the vapor deposition direction constant, for example, a shielding plate having a slit-like opening disposed so as to face the vapor deposition surface of the workpiece W is provided, and the beam parallel of the film component flying from the vapor deposition source is provided. Measures are taken to increase the degree.

Next, with reference to FIG. 6, the relationship between the formation of the alignment film 18 of the example, Comparative Example 1 and Comparative Example 2, and the display quality and productivity of the liquid crystal device 100 will be described. FIG. 6 is a table showing the inorganic alignment film forming conditions in Examples, Comparative Examples 1 and 2, and evaluation of display quality and productivity in the liquid crystal device.
As shown in FIG. 6, the conditions for forming the alignment film 18 in the example, comparative example 1, and comparative example 2 are as follows.
(Example)
The presence or absence of the plurality of recesses 11a in the base insulating film 11 is “present”, and the shape and arrangement of the recesses 11a are circular as described above, φ500 nm, the arrangement interval 1 μm, and the depth of the recesses 11a is 10 nm. The oblique deposition was carried out so that the pixel electrode 15 had a thickness of 20 nm, the inorganic alignment film had an oblique deposition rate of 1.5 nm / min, the elevation angle was 48 °, and the orientation film 18 had a thickness of about 70 nm to 80 nm. .

(Comparative Example 1)
The presence or absence of the plurality of recesses 11a in the base insulating film 11 is “no”, the film thickness of the pixel electrode 15 is 140 nm, the oblique deposition rate of the inorganic alignment film is 1.5 nm / min, the elevation angle is 48 °, and the film of the alignment film 18 The oblique deposition was performed so that the thickness was approximately 70 nm to 80 nm.

(Comparative Example 2)
The presence or absence of the plurality of recesses 11a in the base insulating film 11 is “no”, the film thickness of the pixel electrode 15 is 20 nm, the oblique deposition rate of the inorganic alignment film is 1.25 nm / min, the elevation angle is 50 °, and the film of the alignment film 18 The oblique deposition was performed so that the thickness was approximately 70 nm to 80 nm.

  In Comparative Example 1, the thickness of the pixel electrode 15 is thicker than that of the example. Therefore, a portion where the column 18a does not grow sufficiently between the pixel electrodes 15 during oblique deposition (a shadow in the deposition direction with respect to the outer periphery of the pixel electrode 15). Part) occurred. Although the average pretilt angle θp of the formed alignment film 18 is 4 °, the liquid crystal molecules 50a are substantially vertically aligned by giving a predetermined pretilt near the outer periphery of the pixel electrode 15 where the column 18a is difficult to grow. It was difficult. Therefore, an appropriate vertical alignment state of the liquid crystal molecules 50a cannot be obtained at the outer edge portion of the pixel P, and when the liquid crystal layer 50 is driven by applying a driving voltage between the pixel electrode 15 and the common electrode 23, for example, Light leakage or the like was observed at the outer edge of the pixel P. Therefore, the evaluation of the display quality in the comparative example 1 was set to x.

  In Comparative Example 2, the thickness of the pixel electrode 15 is the same as that of the example, but the plurality of recesses 11a are not formed in the base insulating film 11, and the surface of the element substrate 10 on which the pixel electrode 15 is formed is It is in a flatter state than Comparative Example 1. In order to form the alignment film 18 so as to have the same film thickness as the example and the comparative example 1, the elevation angle is set larger (that is, the angle θb in the vapor deposition direction is smaller) than the example and the comparative example 1, and the vapor deposition rate is set. Without slowing down, it was difficult for the inorganic material crystal to grow on the deposition surface. The pretilt angle θp of the liquid crystal molecules 50a in the formed alignment film 18 was 4 °, and the evaluation of display quality was ○ without any defect. However, the productivity was reduced because the deposition rate was lower than that of Comparative Example 1. The productivity was evaluated as x.

  Compared with Comparative Example 1 and Comparative Example 2, the example in which the plurality of recesses 11a are formed in the base insulating film 11 is the same vapor deposition as Comparative Example 1 even though the pixel electrode 15 is thinner than Comparative Example 1. An alignment film 18 having the same pretilt angle θp (4 °) and the same film thickness (70 nm to 80 nm) at the rate and the elevation angle was obtained. Since the pixel electrode 15 is thinner than the comparative example 1, the column 18a grows evenly on the surface 11b (see FIG. 3) of the base insulating film 11 between the pixel electrodes 15, and light leakage at the outer edge of the pixel P occurs. The display quality was evaluated as ○. Since the deposition rate was the same as in Comparative Example 1, the evaluation of productivity was evaluated as ◯.

In addition, the structure of the opposing board | substrate 20 in an Example, the comparative example 1, and the comparative example 2 is the same. Specifically, as shown in FIG. 3, an interlayer film layer 22, a common electrode 23, and an alignment film 24 are sequentially formed on the surface of the counter substrate 20 facing the liquid crystal layer 50.
The common electrode 23 is made of a transparent conductive film such as ITO, and has a thickness of about 140 nm. Since the common electrode 23 is formed so as to straddle a plurality of pixels P in the counter substrate 20, no step is generated between the pixels.

According to the embodiment described above, the following effects can be obtained.
(1) According to the liquid crystal device 100 and the manufacturing method thereof, the pixel electrode 15 is formed so as to be in contact with the base insulating film 11 in which the plurality of recesses 11 a are formed, and the plurality of recesses 11 a are reflected on the surface of the pixel electrode 15. The recessed surface 15a thus formed is formed. Since the alignment film 18 is formed by oblique vapor deposition on the surface of the pixel electrode 15 having the concave surface 15a, the pretilt of the column 18a is efficiently developed as compared with the case where the surface of the pixel electrode 15 is flat. That is, it is possible to efficiently form the alignment film 18 in which the liquid crystal molecules 50a having negative dielectric anisotropy are substantially vertically aligned by giving a predetermined pretilt. Therefore, the liquid crystal device 100 having stable optical characteristics and high productivity can be provided or manufactured.
(2) Since the plurality of recesses 11a are formed so that the roughness Ra of the surface of the base insulating film 11 is 5 nm or more and 20 nm or less, and the pixel electrode 15 is formed so that the film thickness is 10 nm or more and 50 nm or less. A recess surface 15a is formed on the surface of the pixel electrode 15 in which the recess 11a of the base insulating film 11 is reliably reflected. In other words, even if the thickness of the pixel electrode 15 is reduced in consideration of the optical characteristics, the plurality of recesses 11a are formed in the base insulating film 11, so that the pixel electrode 15 can be processed without processing the pixel electrode 15 itself. The concave surface 15a can be formed on the surface of the substrate. Therefore, the alignment film 18 can be efficiently formed by oblique deposition, and the alignment unevenness due to the unevenness of the alignment film 18 on the liquid crystal layer 50 side is reduced, and the liquid crystal device has both stable optical characteristics and display quality. 100 can be provided or manufactured.
(3) Since the thickness of the pixel electrode 15 is 10 nm or more and 50 nm or less, the step at the outer peripheral edge of the pixel electrode 15 is smaller than that of the comparative example 1, and the column 18a on the surface 11b of the base insulating film 11 between the pixel electrodes 15 It is difficult to hinder growth. That is, the formation unevenness of the alignment film 18 around the pixel electrode 15 is reduced, and the liquid crystal device 100 having more stable optical characteristics and display quality can be provided or manufactured.

(Second Embodiment)
<Electronic equipment>
Next, a projection display device as an electronic apparatus according to the present embodiment will be described with reference to FIG. FIG. 7 is a schematic diagram illustrating a configuration of a projection display device as an electronic apparatus.

  As shown in FIG. 7, a projection display apparatus 1000 as an electronic apparatus according to the present embodiment includes a polarization 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 light valves 1210, 1220, and 1230 use the liquid crystal device 100 that can obtain stable optical characteristics and can be manufactured with high productivity. Display quality and high cost performance.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. The manufacturing method of the liquid crystal device 100 and electronic equipment to which the liquid crystal device 100 is applied are also included in the technical scope of the present invention. Various modifications other than the above embodiment are conceivable. Hereinafter, a modification will be described.

(Modification 1) In the liquid crystal device 100 and the manufacturing method thereof, the formation of the plurality of recesses is not limited to the base insulating film 11 of the pixel electrode 15. FIG. 8 is a schematic cross-sectional view illustrating a pixel structure of a liquid crystal device according to a modification. Note that the same components as those of the liquid crystal device 100 are denoted by the same reference numerals, and description thereof is omitted. For example, as shown in FIG. 8, a liquid crystal device 150 according to a modified example includes liquid crystal molecules 50 a having negative dielectric anisotropy by an element substrate 10 having pixel electrodes 15 and a counter substrate 20 having a common electrode 23. The liquid crystal layer 50 is sandwiched. An inorganic insulating film 12 made of, for example, silicon oxide covering the plurality of pixel electrodes 15 of the element substrate 10 is provided, and the surface roughness Ra of the insulating film 12 on the liquid crystal layer 50 side is 5 nm or more and 20 nm or less. A plurality of recesses 12a are formed to form the recess surface in the present invention. The thickness of the insulating film 12 is approximately 50 nm to 100 nm. An alignment film 18 is formed by oblique deposition on the insulating film 12 having a plurality of recesses 12a. Similarly, an alignment film 24 is formed by oblique deposition on the surface of the common substrate 23 facing the liquid crystal layer 50 of the counter substrate 20.
If the plurality of recesses 12 a are formed in the insulating film 12 covering the pixel electrode 15, the alignment film 18 can be efficiently formed regardless of the thickness of the pixel electrode 15.

  (Modification 2) The configuration and method of forming an inorganic alignment film by oblique vapor deposition on the surface where a plurality of recesses are formed are not limited to being applied to the element substrate 10 having the pixel electrodes 15. For example, in the counter substrate 20, a plurality of recesses may be formed in the interlayer film layer 22 located below the common electrode 23, or an insulating film that covers the common electrode 23 is formed, and the liquid crystal layer 50 side of the insulating film is formed. A plurality of recesses may be formed on the surface facing the surface.

  (Modification 3) The configuration and method of forming an inorganic alignment film by oblique vapor deposition on the surface having a plurality of recesses is not limited to being applied to the transmissive liquid crystal device 100. The present invention can also be applied to a reflective liquid crystal device including a pixel electrode 15 having light reflectivity. The reflective liquid crystal device is not limited to the pixel electrode 15 having light reflectivity. For example, a reflective layer made of light reflective Al (aluminum) or an alloy of Al is provided, and the surface of the reflective layer is formed. After forming a plurality of recesses by etching, the light transmissive pixel electrode 15 may be stacked on the reflective layer. However, it is necessary to form a concave shape so that the light reflectance on the surface of the pixel electrode 15 is not significantly reduced.

  (Modification 4) The electronic apparatus to which the liquid crystal device 100 can be applied is not limited to the projection display device 1000 of the above embodiment. For example, projection-type HUD (head-up display), direct-view type HMD (head-mounted display), electronic book, personal computer, digital still camera, LCD TV, viewfinder type or monitor direct-view type video recorder, car navigation system It can be suitably used as a display unit of an information terminal device such as an electronic notebook or POS.

  DESCRIPTION OF SYMBOLS 10 ... Element board | substrate, 11 ... Base insulating film, 11a ... Concave part of base insulating film, 12 ... Insulating film, 12a ... Concave part of insulating film, 15 ... Pixel electrode, 15a ... Concave or concave surface of pixel electrode, 18 ... Inorganic orientation Alignment film as film, 20 ... counter substrate, 23 ... common electrode, 24 ... alignment film as inorganic alignment film, 50 ... liquid crystal layer, 50a ... liquid crystal molecule, 100, 150 ... liquid crystal device, 1000 ... projection as electronic equipment Type display device.

Claims (9)

A first substrate;
A second substrate;
A liquid crystal layer composed of liquid crystal molecules having negative dielectric anisotropy sandwiched between the first substrate and the second substrate;
A base insulating film provided between the first substrate and the liquid crystal layer and having a plurality of recesses;
An electrode provided between the base insulating film and the liquid crystal layer, and having a concave surface corresponding to the base insulating film;
A liquid crystal device comprising: an inorganic alignment film formed by oblique vapor deposition on the concave surface. A first substrate;
A second substrate;
A liquid crystal layer composed of liquid crystal molecules having negative dielectric anisotropy sandwiched between the first substrate and the second substrate;
An electrode provided between the first substrate and the liquid crystal layer;
An insulating film provided between the electrode and the liquid crystal layer and having a recess surface in which a plurality of recesses are formed;
A liquid crystal device comprising: an inorganic alignment film formed by oblique vapor deposition on the concave surface.   3. The liquid crystal device according to claim 1, wherein roughness Ra of the surface of the recess is 5 nm or more and 20 nm or less. The electrode is a pixel electrode;
4. The liquid crystal device according to claim 1, wherein the pixel electrode has a thickness of 10 nm to 50 nm. A method of manufacturing a liquid crystal device in which a liquid crystal layer composed of liquid crystal molecules having negative dielectric anisotropy is sandwiched between a first substrate and a second substrate,
Forming a base insulating film on the side of the first substrate facing the liquid crystal layer;
A recess forming step of forming a plurality of recesses on the surface of the base insulating film facing the liquid crystal layer;
An electrode forming step of forming an electrode having a concave surface corresponding to the base insulating film by forming a conductive film covering the base insulating film and patterning the conductive film;
An alignment film forming step of forming an inorganic alignment film on the concave surface by oblique vapor deposition;
A method of manufacturing a liquid crystal device, comprising: A method of manufacturing a liquid crystal device in which a liquid crystal layer composed of liquid crystal molecules having negative dielectric anisotropy is sandwiched between a first substrate and a second substrate,
Forming an electrode on the side of the first substrate facing the liquid crystal layer;
Forming an insulating film covering the electrodes;
A recess forming step of forming a plurality of recesses on a surface of the insulating film facing the liquid crystal layer to form a recess surface; an alignment film forming step of forming an inorganic alignment film on the recess surface by oblique vapor deposition; ,
A method of manufacturing a liquid crystal device, comprising:   The method for manufacturing a liquid crystal device according to claim 5, wherein in the electrode forming step, the pixel electrode as the electrode is formed so as to have a thickness of 10 nm to 50 nm.   8. The liquid crystal device manufacturing method according to claim 5, wherein, in the recess forming step, the plurality of recesses are formed so that roughness Ra of the surface of the recess is 5 nm or more and 20 nm or less. Method.   An electronic apparatus comprising the liquid crystal device according to any one of claims 1 to 4.

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