Method for manufacturing inorganic alignment film, liquid crystal device, and electro-optical device

Abstract

A method for manufacturing an inorganic alignment film, a liquid crystal device, and an electro-optical device. A method for manufacturing an inorganic alignment film, a liquid crystal device, and an electro-optical device that ensure liquid crystal alignment and suppress liquid crystal deterioration are provided. The method for manufacturing an inorganic alignment film includes: a first step of forming a pixel electrode on a substrate; a second step of evaporating a first film that has a plurality of first columns with a long axis direction along the Z-axis direction to cover the substrate and the pixel electrode; a third step of evaporating a second film that has a plurality of second columns with a long axis direction intersecting the Z-axis direction at a first angle on the plurality of first columns; a fourth step of forming a protective film by atomic deposition on the plurality of second columns; and a fifth step of evaporating a third film that has a plurality of third columns with a long axis direction at a second angle smaller than the first angle with respect to the Z-axis direction and is thinner than the second film on the protective film.

Description

Technical Field

[0001] This invention relates to a method for manufacturing inorganic alignment films, liquid crystal devices, and electro-optical devices. Background Technology

[0002] Previously, electro-optical devices such as projectors equipped with liquid crystal displays (LCDs) were known. In such electro-optical devices, there has been a tendency to use inorganic alignment films in order to increase the light beam density incident on the liquid crystal display compared to direct-viewing LCDs. In particular, further improvements to inorganic alignment films are being researched to cope with the increasing brightness of light sources such as projection mapping. For example, Patent Document 1 discloses a liquid crystal display device in which an inorganic alignment film is covered with a metal oxide film.

[0003] Patent Document 1: Japanese Patent Application Publication No. 2018-132578

[0004] However, in the liquid crystal device of Patent Document 1, there is a problem that the liquid crystal alignment of the inorganic alignment film is easily reduced. Specifically, there is a possibility that, since the inorganic alignment film is covered by a metal oxide film, it is difficult to exhibit the original liquid crystal alignment of the inorganic alignment film.

[0005] Furthermore, without covering the inorganic alignment film with a metal oxide film, the liquid crystal is prone to deterioration. Specifically, the inorganic alignment film consists of multiple columnar bodies deposited from an inclined direction. Methods for forming inorganic alignment films using evaporation, such as chemical vapor deposition and sputtering, result in films with lower density and are more prone to defects such as dangling bonds. Dangling bonds can easily induce chemical reactions with impurities in the liquid crystal, and if exposed to strong light, free radicals can sometimes be generated. There is a possibility that the liquid crystal will deteriorate due to these free radicals.

[0006] Because gaps exist between the columnar structures constituting the inorganic alignment film, liquid crystal molecules can easily enter these gaps in the inorganic alignment film not covered by the metal oxide film. Therefore, the contact area between the liquid crystal and the inorganic alignment film increases, potentially making the liquid crystal more prone to deterioration. That is, a method for manufacturing an inorganic alignment film that ensures liquid crystal alignment and suppresses liquid crystal deterioration is sought. Summary of the Invention

[0007] A method for manufacturing an inorganic alignment film includes: a first step of forming an electrode on a substrate; a second step of vapor deposition forming a first film covering the substrate and the electrode, the first film having a plurality of first pillars whose long axis is oriented along the direction normal to the substrate; a third step of vapor deposition forming a second film on the plurality of first pillars, the second film having a plurality of second pillars whose long axis is oriented at a first angle relative to the direction normal; a fourth step of forming a protective film on the plurality of second pillars by atomic deposition; and a fifth step of vapor deposition forming a third film on the protective film, the third film having a plurality of third pillars whose long axis is oriented at a second angle relative to the direction normal, the second angle being smaller than the first angle, and the third film being thinner than the second film.

[0008] A liquid crystal device includes: a first substrate having a pixel electrode and a first alignment film disposed on the pixel electrode; a second substrate having a counter electrode and a second alignment film disposed on the counter electrode; and a liquid crystal layer disposed between the first substrate and the second substrate, wherein at least one of the first substrate and the second substrate has: a first film; a second film disposed on the liquid crystal layer side of the first film; a protective film disposed on the liquid crystal layer side of the second film; and a third film disposed on the liquid crystal layer side of the protective film, wherein the first film has a plurality of first pillars in the direction of the major axis along the normal of the first substrate and the second substrate, the second film has a plurality of second pillars in the direction of the major axis relative to the direction along the normal at a first angle, and the third film has a plurality of third pillars in the direction of the major axis relative to the direction along the normal at a second angle smaller than the first angle, and the thickness of the third film in the direction along the normal is thinner than that of the second film.

[0009] The electro-optical device includes the aforementioned liquid crystal device. Attached Figure Description

[0010] Figure 1 This is a schematic top view showing the structure of the liquid crystal device according to the first embodiment.

[0011] Figure 2 This is a schematic cross-sectional view showing the structure of a liquid crystal device.

[0012] Figure 3 This is an equivalent circuit diagram showing the electrical structure of a liquid crystal device.

[0013] Figure 4 This is a schematic cross-sectional view showing the structure of inorganic alignment films, etc., in a component substrate.

[0014] Figure 5 This is a schematic cross-sectional view showing the structure of an inorganic alignment film, etc., in an opposing substrate.

[0015] Figure 6 This is a flowchart illustrating a method for manufacturing an inorganic orientation film according to the second embodiment.

[0016] Figure 7 This is a schematic cross-sectional view illustrating a method for manufacturing an inorganic orientation film.

[0017] Figure 8 This is a schematic cross-sectional view illustrating a method for manufacturing an inorganic orientation film.

[0018] Figure 9 This is a schematic cross-sectional view illustrating a method for manufacturing an inorganic orientation film.

[0019] Figure 10 This is a schematic cross-sectional view illustrating a method for manufacturing an inorganic orientation film.

[0020] Figure 11 This is a schematic diagram showing the structure of a projection-type display device as an electro-optical device according to the third embodiment.

[0021] Label Explanation

[0022] 1B, 1G, 1R, 100: Liquid crystal device; 10: Element substrate as first substrate; 10s, 20s: Substrate; 15: Pixel electrode; 18: Inorganic alignment film as first alignment film; 20: Counter substrate as second substrate; 21: Counter electrode; 22: Alignment film as second alignment film; 50: Liquid crystal layer; 181, 221: First film; 182, 222: Second film; 183, 223: Third film; 184, 224: Protective film; 1000: Projection type display device as electro-optic device; C1: First pillar; C2: Second pillar; C3: Third pillar; S1: First process; S2: Second process; S3: Third process; S4: Fourth process; S5: Fifth process; S6: Sixth process; θ1: First angle; θ2: Second angle. Detailed Implementation

[0023] In the following figures, label the Z-axis or mutually perpendicular coordinate axes (XYZ axes) as needed. Designate the direction indicated by each arrow as the "+" direction and the opposite direction as the "-" direction. Sometimes the +Z direction is referred to as "up" and the -Z direction as "down," and viewing from the +Z direction is called "top view" or "view from above." Additionally, to ensure that each layer and component is easily identifiable, its scale may differ from the actual dimensions.

[0024] Furthermore, for example, relative to the substrate, such a description on the substrate indicates any of the following situations: disposed on the substrate in contact with the substrate; disposed on the substrate with other structures in between; or partially disposed on the substrate in contact with the substrate and partially disposed on the substrate with other structures in between. In addition, the thickness of the film or other structure disposed on the substrate refers to the dimension along the normal direction of the substrate, i.e., the Z-axis direction. However, the thickness of the protective film described later is not limited to this.

[0025] 1. First Implementation Method

[0026] In this embodiment, an active-drive type liquid crystal device equipped with a thin-film transistor (TFT) is illustrated. (Refer to...) Figures 1 to 3 The structure of the liquid crystal device 100 according to this embodiment will be described. Figure 2 Showing contains Figure 1 The line segment H-H' and the cross section along the YZ plane. Additionally, in Figure 2 In the illustration, the size and quantity of liquid crystals contained in the liquid crystal layer are different from the actual values.

[0027] like Figure 1 As shown, the liquid crystal device 100 includes a component substrate 10 as a first substrate, a counter substrate 20 as a second substrate, and a liquid crystal layer described later. The component substrate 10 and the counter substrate 20 are generally rectangular when viewed from above. The component substrate 10 and the counter substrate 20 are overlapped and bonded via a sealing material 60 disposed along the outer edge of the counter substrate 20. A display area E containing a plurality of pixels P is provided inside the sealing material 60. The plurality of pixels P are arranged in a matrix in the directions along the X and Y axes.

[0028] The sealing material 60 comprises a resin with curable properties such as thermosetting and UV curing. Therefore, after applying the raw material of the sealing material 60 to the component substrate 10 and the opposing substrate 20, the resin is cured, and the sealing material 60 can be formed into a desired shape.

[0029] The component substrate 10 includes a data line driving circuit 101, two scan line driving circuits 102, a check circuit 103, and multiple external connection terminals 104. The component substrate 10 is larger than the opposing substrate 20 when viewed from above. Multiple external connection terminals 104 are provided on the component substrate 10 in areas that do not overlap with the opposing substrate 20, and the data line driving circuit 101 is disposed between the multiple external connection terminals 104 and the sealing material 60.

[0030] A partition 24 surrounding the display area E is provided between the sealing material 60 and the display area E. The partition 24 is generally rectangular, with two sides along the Y-axis and the other two sides along the X-axis. Each scan line drive circuit 102, when viewed from above, is arranged overlappingly on the two sides along the Y-axis. The two scan line drive circuits 102 are electrically connected via wiring 107. A check circuit 103, when viewed from above, is arranged overlappingly on one of the two sides along the X-axis in the +Y direction. The check circuit 103 is electrically connected to the data lines described later.

[0031] The data line driving circuit 101 and the two scan line driving circuits 102 are electrically connected to the external connection terminal 104. Vertical conductive sections 106 are provided at the four corners of the opposing substrate 20.

[0032] like Figure 2 As shown, the element substrate 10 and the opposing substrate 20 are disposed opposite each other and separated along the Z-axis by a sealing material 60. A liquid crystal layer 50 is disposed between the element substrate 10 and the opposing substrate 20, and is surrounded by the element substrate 10, the opposing substrate 20, and the sealing material 60. The liquid crystal layer 50 comprises liquid crystal 50a. The liquid crystal 50a has positive or negative dielectric anisotropy. In this embodiment, a liquid crystal 50a with negative dielectric anisotropy is used. Here, liquid crystal 50a refers to individual liquid crystal molecules or an aggregate of individual liquid crystal molecules constituting the liquid crystal 50a.

[0033] The component substrate 10 includes a substrate 10s as the main body of the substrate, a wiring layer including a TFT 30 as a transistor, a pixel electrode 15, and an inorganic alignment film 18 as a first alignment film. The component substrate 10 is a flat plate with its main surface along the XY plane. In the component substrate 10, the liquid crystal layer 50 is arranged in the order of substrate 10s, the wiring layer, and the pixel electrode 15, and the inorganic alignment film 18 is disposed on it.

[0034] The substrate 10s is a flat plate-shaped component that is both transparent and insulating. The substrate 10s is, for example, a glass substrate or a quartz substrate. The TFT 30 is disposed between multiple interlayer insulating layers disposed on the substrate 10s. Furthermore, transparentness refers to the transmittance of visible light, preferably 50% or more.

[0035] The pixel electrode 15 is transparent. The pixel electrode 15 may contain transparent conductive materials such as ITO (Indium Tin Oxide), IZO (Indium Zinc Oxide), and FTO (Fluorine-doped tin oxide). In the liquid crystal device 100, ITO is used as the transparent conductive material.

[0036] An inorganic alignment film 18 is disposed on the pixel electrode 15, with its upper surface facing the liquid crystal layer 50. The inorganic alignment film 18 has light transmittance and insulation properties, and includes a first film, a second film, a protective film, and a third film, which will be described later.

[0037] The counter substrate 20 includes a substrate 20s as the main body of the substrate, a separator 24, an insulating layer 25, a counter electrode 21, and an inorganic alignment film 22 as a second alignment film. The counter substrate 20 is a flat plate with its main surface along the XY plane. In the counter substrate 20, the substrate 20s, the separator 24, the insulating layer 25, and the counter electrode 21 are arranged toward the liquid crystal layer 50 in that order, and the inorganic alignment film 22 is provided in its -Z direction.

[0038] The substrate 20s is a flat, plate-shaped component that is both transparent and insulating. The substrate 20s is, for example, a glass substrate or a quartz substrate. The insulating layer 25 is both transparent and insulating. The material of the insulating layer 25 is, for example, an inorganic material such as silicon oxide. The counter electrode 21 is an electrode disposed opposite to the plurality of pixel electrodes 15. The counter electrode 21 contains the aforementioned transparent conductive material. The counter electrode 21 and the pixel electrodes 15 apply an electric field to the liquid crystal layer 50.

[0039] An inorganic alignment film 22 is disposed on the counter electrode 21, with its lower surface facing the liquid crystal layer 50. The inorganic alignment film 22 has light transmittance and insulation properties, and includes a first film, a second film, a protective film, and a third film, which will be described later.

[0040] Inorganic alignment films 18 and 22 are manufactured using the manufacturing method for inorganic alignment films 18 and 22 described later. The inorganic alignment films 18 and 22 are formed based on the optical design of the liquid crystal device 100. The inorganic alignment films 18 and 22 have the function of aligning the liquid crystal 50a of the liquid crystal layer 50, and the alignment state of the liquid crystal 50a changes according to a voltage applied corresponding to the image signal described later. In this embodiment, the inorganic alignment films 18 and 22 align the liquid crystal 50a, which has negative dielectric anisotropy, substantially perpendicularly.

[0041] Inorganic alignment films 18 and 22 are pre-tilted to align liquid crystal 50a. The pre-tilting direction of liquid crystal 50a intersects the X-axis and Y-axis. The pre-tilting direction of liquid crystal 50a is defined by the evaporation direction during the formation of inorganic alignment films 18 and 22. Preferably, the pre-tilting direction of liquid crystal 50a is set to an azimuth angle of 4 degrees or more and 6 degrees or less with respect to the Z-axis, for example, 5 degrees. Details regarding inorganic alignment films 18 and 22 will be described later.

[0042] The substrates 10s and 20s are, for example, flat plates with light transmittance and insulation, such as glass substrates and quartz substrates. In this specification, light transmittance refers to a visible light transmittance of 50% or more.

[0043] The liquid crystal device 100 is a transmissive type, where light L is incident from the side of the opposing substrate 20 (i.e., in the +Z direction) and exits from the element substrate 10 via the liquid crystal layer 50. As light L passes through the liquid crystal layer 50, it is modulated according to the orientation state of the liquid crystal 50a. The incident direction of light L relative to the liquid crystal device 100 is not limited to the above; it can also be a structure where light L is incident from the element substrate 10 side. Furthermore, the liquid crystal device 100 is not limited to the transmissive type; it can also be a reflective type. The liquid crystal device 100 employs a normally white mode or a normally black mode optical design. The liquid crystal device 100 may also have polarizing elements on both the incident and exit sides of light L.

[0044] like Figure 3 As shown, the liquid crystal device 100 has multiple data lines 6, scan lines 3, and capacitor lines 8 as mutually insulated signal wiring. The scan lines 3 extend along the X-axis, and the data lines 6 and capacitor lines 8 extend along the Y-axis. Furthermore, the capacitor lines 8 are not limited to a structure along the Y-axis; they can also be a structure along the X-axis.

[0045] Pixel electrodes 15, TFTs 30, and capacitor elements 16 are arranged in the area divided by scan lines 3, data lines 6, and capacitor lines 8 for each pixel P, forming the pixel circuit of pixel P. Signal wiring such as scan lines 3, data lines 6, and capacitor lines 8 are arranged in the aforementioned wiring layer.

[0046] Scan line 3 is electrically connected to the gate of TFT 30, which serves as a switching element. Data line 6 is electrically connected to the source / drain region of the data line side of TFT 30. Scan line 3 simultaneously controls the on / off state of TFT 30 located in the same row. Pixel electrode 15 is electrically connected to the source / drain region of the pixel electrode side of TFT 30.

[0047] Data line 6 is electrically connected to the aforementioned data line driving circuit 101, and supplies the image signal from the data line driving circuit 101 to pixel P. The image signal can be supplied to each data line 6 in line sequence, or to multiple adjacent data lines 6 in groups.

[0048] Scan line 3 is electrically connected to the scan line drive circuit 102 described above, and supplies the scan signal from the scan line drive circuit 102 to pixel P. The scan signal is supplied to scan line 3 in a predetermined timing pulse sequence.

[0049] With the input of a scan signal, the TFT 30 is turned on for a certain period of time, and an image signal is applied to the pixel electrode 15 at a predetermined timing. The image signal is written to the liquid crystal layer 50 via the pixel electrode 15 at a predetermined level and held between the pixel electrode 15 and the counter electrode 21 sandwiching the liquid crystal layer 50 for a certain period of time. During this time, the orientation state of the liquid crystal 50a changes according to the voltage applied corresponding to the image signal. To prevent leakage of the held image signal, the capacitor element 16 is electrically connected in parallel with the liquid crystal capacitor disposed between the pixel electrode 15 and the counter electrode 21. The capacitor element 16 is disposed in the layer between the TFT 30 and the capacitor line 8.

[0050] Reference Figure 4 and Figure 5 The detailed structure of the inorganic alignment films 18 and 22 in the liquid crystal device 100 will be described. Figure 4 and Figure 5 Showing contains Figure 1 A cross-section of line segment J-J' perpendicular to the XY plane. Line segment J-J' is along the pre-tilting direction of the aforementioned liquid crystal 50a. Figure 4 and Figure 5 In order to facilitate observation of the accompanying drawings, a portion of the structure of the liquid crystal device 100 has been omitted.

[0051] like Figure 4 As shown, the inorganic alignment film 18, which is the first alignment film, has a first film 181, a second film 182, a protective film 184, and a third film 183. Furthermore, in... Figure 4 The various wiring layers and pixel electrodes 15 disposed on the substrate 10s are omitted from the illustration. Additionally, in... Figure 4 For ease of illustration, the size and number of liquid crystals 50a contained in the liquid crystal layer 50 are different from the actual size.

[0052] The first film 181 is disposed at the bottom of the inorganic alignment film 18. The first film 181 has a plurality of first pillars C1. Each first pillar C1 is a columnar crystal such as silicon oxide, aluminum oxide, or magnesium oxide, formed by vapor deposition. The direction of each first pillar C1 along the normal to the element substrate 10, that is, along the Z-axis, is the major axis direction. In the liquid crystal device 100, silicon oxide is used as the first pillar C1. The thickness of the first film 181 is preferably set to 36 nm or more and 44 nm or less, for example, about 40 nm.

[0053] The second film 182 is disposed above the first film 181, i.e., on the side of the liquid crystal layer 50, and grounded to the first film 181. The second film 182 has a plurality of second pillars C2. Each second pillar C2 is a columnar crystal such as silicon oxide, aluminum oxide, or magnesium oxide, formed by vapor deposition. The long axis direction of each second pillar C2 forms a first angle θ1 relative to the direction along the Z-axis. The first angle θ1 is, for example, about 55 degrees. In the liquid crystal device 100, silicon oxide is used as the second pillar C2. The thickness of the second film 182 is preferably set to be 18 nm or more and 22 nm or less, for example, about 20 nm.

[0054] A protective film 184 is disposed on the surface of the second film 182 on the side containing the liquid crystal layer 50. Specifically, at each of the second pillars C2 of the second film 182, a protective film 184 is disposed on the surface other than the area in contact with the first film 181. The protective film 184 covers the aforementioned surfaces of the plurality of second pillars C2 and fills or reduces the gaps between the second pillars C2. This suppresses contact between the plurality of second pillars C2 and the liquid crystal 50a.

[0055] The protective film 184 contains silicon oxide and is formed by atomic layer deposition (ALD). In this embodiment, the protective film 184 is silicon oxide. Therefore, the protective film 184 can be easily formed using relatively inexpensive materials.

[0056] The thickness of the protective film 184 is preferably set to 0.5 nm (5 ) and above and 1.4nm (14 The following applies. Therefore, the liquid crystal orientation of the second film 182 is not excessively reduced, and the deterioration of the liquid crystal 50a can be further suppressed. In this embodiment, the thickness of the protective film 184 is set to approximately 1.0 nm. Furthermore, in this specification, the thickness of the protective films 184 and 224 refers to the dimension in the normal direction of each surface of the second pillar C2, which is a columnar crystal.

[0057] The third film 183 is disposed above the second film 182, i.e., on the side of the liquid crystal layer 50 of the protective film 184, facing the liquid crystal layer 50. The third film 183 enhances the liquid crystal alignment of the second film 182. The third film 183 has a plurality of third pillars C3. Each third pillar C3 is a columnar crystal such as silicon oxide, aluminum oxide, or magnesium oxide, formed by vapor deposition. The long axis direction of each third pillar C3 forms a second angle θ2 relative to the direction along the Z-axis. The second angle θ2 is an angle smaller than the first angle θ1. The second angle θ2 is preferably set to 40 degrees or more and 50 degrees or less, for example, about 45 degrees. In the liquid crystal device 100, silicon oxide is used as the third pillar C3.

[0058] The thickness of the third film 183 is thinner than the thickness of the second film 182. Therefore, the surface area of ​​the third pillar C3 is smaller than that of the second pillar C2, resulting in a reduced contact area with respect to the liquid crystal 50a. This suppresses deterioration of the liquid crystal 50a. The thickness of the third film 183 is preferably set to 5 nm or more and 7 nm or less, for example, about 6 nm.

[0059] The film density of the third film 183 is less than that of the second film 182. That is, the third pillars C3 are sparsely formed relative to the multiple second pillars C2. As a result, the liquid crystal alignment of the third film 183 is improved. In addition, even if the gap between the third pillars C3 increases, by making the thickness of the third film 183 relatively thin, the increase in the contact area with the liquid crystal 50a can be suppressed.

[0060] The film density of the third film 183 and the film density of the second film 182 can be compared by the etching rate in wet etching, i.e., the depth etched per unit time. The higher the film density, the more difficult it is to etch, and the lower the film density, the easier it is to etch, and the higher the etching rate.

[0061] Preferably, the third film 183 undergoes a surface treatment based on a silane coupling agent. This results in the surface of each third pillar C3 being covered with an organosilane compound. Therefore, the reaction between dangling bonds on the surface of each third pillar C3 and water, which is an impurity in the liquid crystal 50a, is suppressed, thus inhibiting the formation of silanol groups. If silanol groups are exposed to strong light, they can sometimes generate free radicals that degrade the liquid crystal 50a. Preventing the formation of silanol groups in the third film 183 further suppresses the deterioration of the liquid crystal 50a.

[0062] like Figure 5 As shown, the inorganic alignment film 22, which is the second alignment film, has a first film 221, a second film 222, a protective film 224, and a third film 223. The first film 221, the second film 222, the protective film 224, and the third film 223 are identical to the structures of the element substrate 10 described above, and repeated descriptions are omitted. Furthermore, in Figure 5 The various wiring layers and counter electrode 21 disposed on the substrate 20s are omitted from the illustration. Additionally, in Figure 5 For ease of illustration, the size and number of liquid crystals 50a contained in the liquid crystal layer 50 are different from the actual size.

[0063] The first film 221 is disposed in the inorganic alignment film 22 at the position closest to the +Z direction. The first film 221 corresponds to the first film 181 of the inorganic alignment film 18. The first film 221 has a plurality of first pillars C1. The direction of each first pillar C1 along the normal to the opposing substrate 20, that is, along the Z-axis, is the major axis direction. The thickness of the first film 221 is, for example, about 40 nm.

[0064] The second film 222 is grounded to the first film 221 in the -Z direction, i.e., on the liquid crystal layer 50 side. The second film 222 corresponds to the second film 182 of the inorganic alignment film 18. The second film 222 has a plurality of second pillars C2. The major axis direction of each second pillar C2 forms a first angle θ1 with respect to the direction along the Z-axis. The thickness of the second film 182 is, for example, about 20 nm.

[0065] A protective film 224 is disposed on the surface of the second film 222 on the side containing the liquid crystal layer 50. The protective film 224 corresponds to the protective film 184 of the inorganic alignment film 18. At each of the second pillars C2 of the second film 222, a protective film 224 is disposed on the surface other than the area in contact with the first film 221. The protective film 224 covers the surfaces of the plurality of second pillars C2 and fills or reduces the gaps between the second pillars C2. This suppresses the contact between the plurality of second pillars C2 and the liquid crystal 50a.

[0066] The protective film 224 contains silicon oxide and is formed by atomic layer deposition (ALD). In this embodiment, the protective film 224 is silicon oxide.

[0067] The thickness of the protective film 224 is preferably set to 0.5 nm (5 ) and above and 1.4nm (14 Below. In this embodiment, the thickness of the protective film 224 is set to approximately 1.0 nm.

[0068] The third film 223 is disposed facing the liquid crystal layer 50 in the -Z direction of the second film 222, i.e., on the side of the protective film 224 towards the liquid crystal layer 50. The third film 223 has a plurality of third pillars C3. The major axis direction of each third pillar C3 forms a second angle θ2 with respect to the direction along the Z-axis. In the liquid crystal device 100, silicon oxide is used as the third pillar C3.

[0069] The thickness of the third film 223 is thinner than the thickness of the second film 222. Therefore, the surface area of ​​the third pillar C3 is smaller than that of the second pillar C2, reducing the area in contact with the liquid crystal 50a. This suppresses deterioration of the liquid crystal 50a. The thickness of the third film 223 is, for example, about 6 nm.

[0070] The film density of the third film 223 is smaller than that of the second film 222, and the multiple third pillars C3 are sparsely formed relative to the multiple second pillars C2. The film density of the third film 223 and the film density of the second film 222 can be compared with the etching rate in wet etching.

[0071] Preferably, the third film 223 undergoes a surface treatment based on a silane coupling agent. As a result, the surface of each third pillar C3 is covered with an organosilane compound, which further suppresses the deterioration of the liquid crystal 50a.

[0072] In this embodiment, the structure is configured as follows: the element substrate 10 has a first film 181, a second film 182, a protective film 184, and a third film 183; the opposing substrate 20 has a first film 221, a second film 222, a protective film 224, and a third film 223. That is, both the element substrate 10 and the opposing substrate 20 have a plurality of first pillars C1, a plurality of second pillars C2, a protective film 184 or a protective film 224, and a third pillar C3. Therefore, liquid crystal alignment can be ensured on both the element substrate 10 and the opposing substrate 20, and deterioration of the liquid crystal 50a can be suppressed.

[0073] Furthermore, the liquid crystal device of the present invention is not limited to the above-described structure, as long as at least one of the element substrate 10 and the opposing substrate 20 has a structure having a plurality of first pillars C1, a plurality of second pillars C2, a protective film 184 or a protective film 224, and a third pillar C3.

[0074] According to this embodiment, the following effects can be obtained.

[0075] This design ensures liquid crystal alignment and suppresses deterioration of the liquid crystal 50a, thereby improving the display quality of the liquid crystal device 100. Specifically, the third films 183 and 223 are thinner than the second films 182 and 222, and the surface area of ​​the third films 183 and 223 is smaller than that of the second films 182 and 222. Therefore, the contact area with the liquid crystal 50a is reduced, suppressing deterioration of the liquid crystal 50a.

[0076] In particular, when forming an alignment film by vapor deposition, dangling bonds are easily generated on the surface of the columnar crystals. These dangling bonds react with water, which is an impurity in the liquid crystal 50a, to generate silanol groups. If these silanol groups are exposed to strong light, they generate free radicals that degrade the liquid crystal 50a. In contrast, by covering the columnar crystals of silicon oxide with protective films 184 and 224, the formation of silanol groups can be prevented.

[0077] Although the liquid crystal alignment of the second films 182 and 222 is slightly weakened due to the protective films 184 and 224, the liquid crystal alignment is enhanced by the third films 183 and 223. Therefore, as inorganic alignment films 18 and 22, liquid crystal alignment is ensured. Through the above, a liquid crystal device 100 is provided that ensures liquid crystal alignment and suppresses the deterioration of liquid crystal molecules.

[0078] 2. Second Implementation Method

[0079] In this embodiment, the manufacturing method of the inorganic alignment films 18 and 22 described above is illustrated, referring to... Figures 6 to 10 Please provide an explanation. Furthermore... Figures 7 to 10 Showing contains Figure 1The section is a line segment J-J' perpendicular to the XY plane. Line segment J-J' is along the tilting direction of the pre-tilted liquid crystal 50a. Additionally, for ease of observation of the accompanying drawings, a portion of the structure is omitted from the illustration.

[0080] like Figure 6 As shown, the manufacturing method of the inorganic alignment films 18 and 22 according to this embodiment includes steps S1 to S6. Furthermore, Figure 6 The process flow is just one example, and is not limited to this.

[0081] In the first step S1, electrodes, various wirings, insulating layers, etc., are formed on the aforementioned substrates 10s and 20s. Pixel electrodes 15, etc., are formed on substrate 10s, and counter electrodes 21, etc., are formed on substrate 20s. The first step S1 can be performed using known methods. Then, the process proceeds to the second step S2. Furthermore, the steps after the second step S2 are common to the inorganic alignment film 18 and the inorganic alignment film 22. Therefore, in the following description, the inorganic alignment film 18 of the element substrate 10 will be used as a representative example, and the description of the inorganic alignment film 22 of the counter substrate 20 will be omitted.

[0082] In the second process S2, as Figure 7 As shown, a first film 181 having a plurality of first pillars C1 is formed by vapor deposition over the substrate 10s and a pixel electrode 15 (not shown). Specifically, silicon oxide molecules are deposited using vacuum vapor deposition (PVD) in the +Z direction relative to the upward-facing main surface of the substrate 10s, thereby growing a plurality of first pillars C1. At this time, the vapor deposition source (not shown) and the substrate 10s are arranged along the Z-axis such that the long axis direction of each first pillar C1 is along the normal direction of the substrate 10s, i.e., along the Z-axis. In the first pillar C1 and the second and third pillars C3 (described later), the long axis direction is the growth direction of the columnar crystals. In this embodiment, the thickness of the first film 181 is set to approximately 40 nm. Then, the process proceeds to step S3.

[0083] In the third process S3, such as Figure 8 As shown, a second film 182 having multiple second pillars C2 is formed by vapor deposition on multiple first pillars C1. Specifically, silicon oxide molecules are deposited from an inclined direction intersecting the Z-axis using vacuum vapor deposition to grow the multiple second pillars C2. At this time, a vapor deposition source and a substrate 10s (not shown) are arranged such that the major axis direction of each second pillar C2 intersects the direction along the Z-axis at a first angle θ1. Furthermore, the angle of the inclined vapor deposition formed by the line segment connecting the vapor deposition source and the substrate 10s and the Z-axis is not necessarily the same as the first angle θ1. In this embodiment, the thickness of the second film 182 is set to approximately 20 nm.

[0084] Here, let's assume that... Figure 8 The first film 181 and the second film 182, as shown in the diagram, are used as alignment films in the comparative example, which can ensure the alignment of the liquid crystal and align the liquid crystal 50a. However, since there is a gap between the second pillars C2, the liquid crystal 50a can easily enter the gap. Therefore, the liquid crystal 50a is in contact not only with the surface above the second film 182, but also with the gap, which can easily cause the liquid crystal 50a to deteriorate. In contrast, the manufacturing method of the inorganic alignment films 18 and 22 in this embodiment reduces the contact area with the liquid crystal 50a by forming the protective film 184, etc., and suppresses the deterioration of the liquid crystal 50a.

[0085] In the fourth process S4, such as Figure 9 As shown, a protective film 184 containing silicon oxide is formed on the plurality of second pillars C2 and on the surface of each second pillar C2 other than the area in contact with the first film 181 by atomic deposition. In this embodiment, silicon oxide is used as the protective films 184 and 224. Therefore, the protective films 184 and 224 can be easily formed with relatively inexpensive materials.

[0086] Atomic deposition is a method in which a thin film is formed by periodically performing a chemical reaction, depositing it in atomic layers. Therefore, compared to vapor deposition-based film formation methods, atomic deposition yields a more uniform and denser film. In particular, it is suitable for forming films in narrow regions such as the gaps between the second pillars C2. The protective films 184 and 224 of this embodiment can be formed using known apparatus.

[0087] To form protective films 184 and 224 from silicon oxide, the process is as follows: First, gases of bis(diethylamino)silane and tris(dimethylamino)silane are introduced into the chamber as precursors to react with the surface of column C2. Next, unreacted precursors are expelled from the chamber, and surface ligands are removed using plasma. By repeating the above process, protective films 184 and 224 of silicon oxide are formed on an atomic-layer basis.

[0088] In step S4, it is preferable to set the thickness of the formed protective films 184 and 224 to 0.5 nm (5 ) and above and 1.4nm (14 Therefore, the liquid crystal orientation of the second films 182 and 222 will not be excessively reduced, and the deterioration of the liquid crystal 50a can be further suppressed. In this embodiment, the thickness of the protective films 184 and 224 is set to approximately 1.0 nm.

[0089] Here, we assume that only Figure 9In the state shown, where only the first film 181 and the second film 182 covered by the protective film 184 are used as alignment films in the comparative example, although the deterioration of the liquid crystal 50a is suppressed, the liquid crystal alignment is weak, making it difficult to align the liquid crystal 50a. In contrast, the manufacturing method of the inorganic alignment films 18 and 22 in this embodiment forms a third pillar C3 on the side of each liquid crystal layer 50 of the protective films 184 and 224 to ensure liquid crystal alignment. Then, the process proceeds to step 5, S5.

[0090] In step S5, such as Figure 10 As shown, a third film 183 having multiple third pillars C3 is deposited on the protective film 184 above the second pillar C2. Specifically, silicon oxide molecules are deposited from an inclined direction intersecting the Z-axis using vacuum evaporation to grow the multiple third pillars C3. At this time, the evaporation source and substrate 10s (not shown) are arranged in the same manner as in the third step S3, such that the long axis direction of each third pillar C3 intersects the direction along the Z-axis at a second angle θ2.

[0091] In step S5, the thickness of the third film 183 is thinner than the thickness of the second film 182. This reduces the contact area with the liquid crystal 50a. The thickness of the third film 183 is set to approximately 6 nm, relative to the thickness of the second film 182, which is approximately 20 nm.

[0092] Furthermore, the film density of the third film 183 is made lower than that of the second film 182. By making the film density of the third film 183 smaller and sparser, the liquid crystal orientation is improved. Even though the film density of the third film 183 is relatively small, since the third film 183 is thinner than the second film 182, the contact area with the liquid crystal 50a is smaller, thus suppressing the deterioration of the liquid crystal 50a.

[0093] To make the third film 183 thinner than the second film 182 and reduce the film density, for example, film formation is performed at an extremely low vacuum and a low rate to form the third film 183. Then, proceed to step 6 S6.

[0094] In step S6, following step S5, the third membrane 183 undergoes a surface treatment based on a silane coupling agent. Specifically, the silane coupling agent is hydrolyzed to generate silanol groups from alkoxy groups. These silanol groups then undergo a dehydration condensation reaction with the hydroxyl groups and other silanol groups on the surface of the third column C3 to form covalent bonds. Thus, an organosilane compound is bonded to the surface of the third column C3.

[0095] Examples of silane coupling agents include hexyltrimethoxysilane, hexyltriethoxysilane, cyclohexylmethyldimethoxysilane, octyltriethoxysilane, and decyltrimethoxysilane.

[0096] Through the above surface treatment, the contact between the surface of the third pillar C3 and moisture, which is an impurity in the liquid crystal 50a, is blocked, thereby further suppressing the deterioration of the liquid crystal 50a. After the above processes, inorganic alignment films 18 and 22 are manufactured.

[0097] According to this embodiment, the following effects can be obtained.

[0098] Inorganic alignment films 18 and 22 are capable of being manufactured to ensure liquid crystal alignment and suppress deterioration of liquid crystal 50a. Specifically, the third films 183 and 223 are thinner than the second films 182 and 222, and the surface area of ​​the third films 183 and 223 is smaller than that of the second films 182 and 222. Therefore, the contact area with the liquid crystal 50a is reduced, suppressing deterioration of the liquid crystal 50a.

[0099] In particular, when forming an alignment film by vapor deposition, dangling bonds are easily generated on the surface of the columnar crystals. These dangling bonds react with water, which is an impurity in the liquid crystal 50a, to generate silanol groups. If these silanol groups are exposed to strong light, they generate free radicals that degrade the liquid crystal 50a. In contrast, if the columnar crystals of silicon oxide are covered with protective films 184 and 224, the formation of silanol groups can be prevented.

[0100] Although the liquid crystal alignment of the second films 182 and 222 is slightly weakened due to the protective films 184 and 224, the liquid crystal alignment is enhanced by the third films 183 and 223. Therefore, as inorganic alignment films 18 and 22, liquid crystal alignment is ensured. Through the above, a method for manufacturing inorganic alignment films 18 and 22 that ensures liquid crystal alignment and suppresses the deterioration of liquid crystal molecules can be provided.

[0101] 3. Third Implementation Method

[0102] As an example of the electro-optical device involved in this embodiment, a projection display device 1000 is shown, referring to... Figure 11 The projection display device 1000 is a projector.

[0103] like Figure 11 As shown, the projection display device 1000 includes a lamp unit 1001, dichroic mirrors 1011 and 1012 of a color separation optical system, three liquid crystal devices 1B, 1G, and 1R, reflectors 1111, 1112, and 1113, relay lenses 1121, 1122, and 1123, a dichroic prism 1130 of a color combining optical system, and a projection lens 1140 of a projection optical system.

[0104] The projection display device 1000 includes a liquid crystal device 100 as described in the above embodiments, which are liquid crystal devices 1R, 1G, and 1B. It is acceptable to use one or more of the liquid crystal devices 1R, 1G, and 1B in the liquid crystal device 100, but more preferably, all of them.

[0105] Lamp unit 1001 is, for example, a discharge-type light source. The type of light source is not limited to this. Solid-state light sources such as light-emitting diodes (LEDs) and lasers can also be used.

[0106] The light emitted from lamp unit 1001 is separated into three colors of light, each with a different wavelength, by dichroic mirrors 1011 and 1012. The three colors of light are approximately red (R), approximately green (G), and approximately blue (B).

[0107] Dichroic mirror 1011 allows red light R to pass through and reflects green light G and blue light B, which have shorter wavelengths than red light R. The red light R passing through dichroic mirror 1011 is reflected by mirror 1111 and enters the liquid crystal device 1R. The green light G reflected by dichroic mirror 1011 is reflected by dichroic mirror 1012 and enters the liquid crystal device 1G. The blue light B reflected by dichroic mirror 1011 passes through dichroic mirror 1012 and enters the relay lens system 1120.

[0108] The relay lens system 1120 includes relay lenses 1121, 1122, and 1123, and reflectors 1112 and 1113. Blue light B has a longer optical path than green light G and red light R, thus its beam tends to amplify. Therefore, relay lens 1122 is used to suppress beam amplification. Blue light B incident on the relay lens system 1120 is focused by relay lens 1121 and reflected at reflector 1112, converging near relay lens 1122. Then, blue light B is incident on the liquid crystal device 1B via reflector 1113 and relay lens 1123.

[0109] Liquid crystal devices 1R, 1G, and 1B are electrically connected to the host circuit of the projection display device 1000. Therefore, when image signals specifying the grayscale levels of red light R, green light G, and blue light B are supplied from the external circuit to the host circuit for processing, liquid crystal devices 1R, 1G, and 1B are driven, and each color light is modulated.

[0110] Red light R, green light G, and blue light B, modulated by liquid crystal devices 1R, 1G, and 1B, are incident on dichroic prism 1130 from three directions. Dichroic prism 1130 combines the incident red light R, green light G, and blue light B. In dichroic prism 1130, red light R and blue light B are reflected at 90 degrees, while green light G is transmitted. Thus, red light R, green light G, and blue light B are combined into display light for displaying a color image and incident on projection lens 1140.

[0111] The projection lens 1140 is positioned facing outwards from the projection display device 1000. The display light is magnified and emitted through the projection lens 1140, and the projected image is projected onto the screen 1200, which is the object of the projection.

[0112] In this embodiment, a projection display device 1000 is exemplified as an electro-optical device, but it is not limited thereto. The liquid crystal device of the present invention can also be applied to electro-optical devices such as projection-type HUDs (Head-Up Displays), direct-view HMDs (Head-Mounted Displays), personal computers, digital cameras, and LCD televisions.

[0113] According to this embodiment, a projection display device 1000 with excellent display quality and the ability to maintain display quality even with relatively strong incident light can be provided.

Claims

1. A method for manufacturing an inorganic alignment film, comprising: The first step involves forming electrodes on a substrate; In the second step, a first film is formed by vapor deposition covering the substrate and the electrode. The first film has a plurality of first pillars in the direction of the major axis along the normal of the substrate. In the third step, a second film is formed by vapor deposition on the plurality of first pillars, the second film having a plurality of second pillars whose long axis direction intersects the direction along the normal at a first angle; In the fourth step, a protective film is formed on the plurality of second pillars by atomic deposition; and In the fifth step, a third film is formed by vapor deposition on the protective film. The third film has a plurality of third pillars whose long axis direction is at a second angle relative to the direction along the normal. The second angle is smaller than the first angle, and the third film is thinner than the second film.

2. The method for manufacturing the inorganic alignment film according to claim 1, wherein, The protective film contains silicon oxide.

3. The method for manufacturing the inorganic alignment film according to claim 1, wherein, Following the fifth step, there is a sixth step where the third membrane undergoes a surface treatment based on a silane coupling agent.

4. The method for manufacturing the inorganic alignment film according to claim 1, wherein, In the fifth step, the membrane density of the third membrane is made to be less than that of the second membrane.

5. The method for manufacturing the inorganic alignment film according to claim 1, wherein, In the fourth step, the thickness of the protective film is set to 5. The above and 14 the following.

6. A liquid crystal device comprising: A first substrate having a pixel electrode and a first alignment film disposed on the pixel electrode; The second substrate has a counter electrode and a second alignment film disposed on the counter electrode; as well as A liquid crystal layer is disposed between the first substrate and the second substrate. At least one of the first substrate and the second substrate has: First membrane; A second film is disposed on the liquid crystal layer side of the first film; A protective film is disposed on the liquid crystal layer side of the second film; as well as A third film is disposed on the liquid crystal layer side of the protective film. The first film has a plurality of first pillars whose direction along the major axis is the direction normal to the first substrate and the second substrate. The second membrane has a plurality of second pillars whose long axis direction forms a first angle with respect to the direction along the normal. The third membrane has a plurality of third pillars whose long axis direction is a second angle smaller than the first angle relative to the direction along the normal, and the thickness of the third membrane in the direction along the normal is thinner than that of the second membrane.

7. The liquid crystal device according to claim 6, wherein, Both the first substrate and the second substrate have the first film, the second film, the protective film, and the third film.

8. The liquid crystal device according to claim 6, wherein, The protective film contains silicon oxide.

9. The liquid crystal device according to claim 6, wherein, The third membrane underwent a surface treatment based on a silane coupling agent.

10. The liquid crystal device according to claim 6, wherein, The membrane density of the third membrane is less than that of the second membrane.

11. The liquid crystal device according to claim 6, wherein, The thickness of the protective film is 5. The above and 14 the following.

12. An electro-optical device comprising the liquid crystal device according to any one of claims 6 to 11.

Images