JP2011154074A - Method for manufacturing electro-optic device, electro-optic device and electronic equipment - Google Patents

Abstract

An alignment film having good alignment characteristics is formed.
A method of manufacturing an electro-optical device includes an electro-optical device (100) including a pair of substrates (10, 20) each having an alignment film (16, 22) that gives a predetermined pretilt angle to an electro-optical material. It is a manufacturing method. In the manufacturing method, on each of a pair of substrates, a liquid material (200) containing a thermal crosslinking agent is applied by spin coating, and the applied liquid material is dried at a high temperature to form an alignment film. A drying step.
[Selection] Figure 5

Description

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

  In an electro-optical device manufactured by this type of manufacturing method, an alignment film for aligning an electro-optical material, such as liquid crystal, constituting the electro-optical device in a predetermined direction is formed. For example, Patent Document 1 describes a method of forming a functional film by applying a liquid material to a substrate and then removing the solvent contained in the liquid material. In particular, when removing the solvent, it is described that the ultimate pressure reached by the reduced pressure is set to be equal to or lower than the saturated vapor pressure of the solvent and the solvent is removed by drying under reduced pressure when the chamber is sealed. Yes.

  Alternatively, Patent Document 2 describes a method in which an alignment film is formed by applying a liquid material from an inkjet head onto a substrate on which a liquid crystal drive electrode is formed. Here, in particular, during application of the liquid material, by supplying an electric current to the drive electrode, the liquid material is heated to below the boiling point to promote fluidization, and after applying the liquid material, an electric current is supplied to the drive electrode. It describes that a liquid is heated to a boiling point or higher and dried.

  Alternatively, Patent Document 3 discloses a stage in which the first chamber and the second chamber are communicated with each other and the pressure is reduced to a predetermined operating pressure in a state in which the substrate coated with the liquid material is accommodated, and the predetermined operating pressure is reached. Describes a method of forming a functional film by a vacuum drying method in which the first chamber is sealed and the solvent is evaporated.

  Alternatively, Patent Document 4 discloses that a polymer material is dissolved in a solvent in which a leveling agent is mixed in a polar main solvent and then applied onto a substrate, and then the substrate is first pre-baked to at least part of the mixed solvent. The alignment film is formed by volatilizing the substrate and then heating the substrate at a temperature higher than that of the pre-bake to polymerize the polymer material.

JP 2006-255553 A JP 2005-134466 A JP 2007-42708 A JP 2002-55346 A

  However, the above-described background art has a technical problem in that uniform alignment characteristics may not be obtained due to the formed film.

  SUMMARY An advantage of some aspects of the invention is that it provides an electro-optical device manufacturing method, an electro-optical device, and an electronic apparatus that can obtain favorable alignment characteristics.

  In order to solve the above-described problems, an electro-optical device manufacturing method according to the present invention is a method for manufacturing an electro-optical device including a pair of substrates each having an alignment film that gives a predetermined pretilt angle to an electro-optical material. A coating step of applying a liquid material containing a thermal crosslinking agent on each of the pair of substrates by a spin coating method; and a drying step of drying the applied liquid material at a high temperature to form the alignment film. Prepare.

  The method for manufacturing an electro-optical device according to the present invention is a method for manufacturing an electro-optical device including a pair of substrates each having an alignment film that gives a predetermined pretilt angle to an electro-optical material such as a liquid crystal. The “predetermined pretilt angle” is set according to the specifications of the electro-optical device to be manufactured.

  The manufacturing method includes a coating process and a drying process. In the coating step, a liquid material containing a thermal crosslinking agent is coated on each of the pair of substrates by a spin coat method. Here, the time for which each of the pair of substrates is rotated by the spin coating method is 120 seconds or less in order to prevent the solvent contained in the liquid from being excessively dried due to the rotation of the substrate. It is desirable that

  The liquid comprises a main solvent such as γ-butyrolactone or N-methylpyrrolidone, a polymer material such as polyimide, and a thermal crosslinking agent such as a diamine-based thermal crosslinking agent. Here, the weight of the polymer material is desirably 4% or less with respect to the weight of the liquid. The liquid may further contain a leveling agent such as butyl cellosolve.

  In the drying step, the applied liquid material is dried at a high temperature to form an alignment film. In addition, what is necessary is just to apply a well-known various method for the high temperature drying of a liquid.

  According to the inventor's research, the following matters have been found. That is, in the spin coating method, after a liquid material is dropped on a substrate, leveling is performed by spin processing. Thereafter, when the liquid is dried by spin drying, the solvent contained in the liquid gradually decreases. For this reason, the polymer material aggregates and adheres in the process of decreasing the solvent. Then, the main chain of the polymer material and, for example, a leveling agent, etc. are unevenly distributed, and there is a possibility that uniform alignment characteristics cannot be obtained.

  However, in the present invention, in the drying step, the alignment material is formed by drying the liquid containing the thermal crosslinking agent at a high temperature. That is, the alignment film is formed by instantaneously drying the solvent while a relatively large amount of the solvent remains. Here, in a state where a relatively large amount of the solvent remains, the main chain of the polymer material contained in the liquid, the thermal crosslinking agent, and the like are dispersed in the solvent. In this state, when the liquid is dried at a high temperature, it has been found by the inventors' research that aggregation of the polymer material can be suppressed. Therefore, according to the method for manufacturing the electro-optical device of the present invention, good alignment characteristics can be obtained.

  In addition, since the distribution of the additive (that is, the additive contained in the liquid material) in the alignment film can be made close to uniform, the adsorption balance of impurity ions between the pair of substrates constituting the electro-optical device is not uniform. Can improve sex. As a result, it is possible to suppress a deviation in electrical characteristics of the electro-optical device, and thus it is possible to manufacture a highly reliable electro-optical device.

  In order to solve the above-described problem, the electro-optical device of the present invention includes a pair of substrates each having an alignment film that gives a predetermined pretilt angle to the electro-optical material, and the alignment film includes each of the pair of substrates. A liquid material containing a thermal cross-linking agent is applied onto the substrate by spin coating, and then the applied liquid material is dried at a high temperature.

  According to the electro-optical device of the present invention, since the alignment film is formed by the same method as the above-described method for manufacturing the electro-optical device of the present invention, good alignment characteristics can be obtained.

  In order to solve the above problems, an electronic apparatus according to the present invention includes the above-described electro-optical device according to the present invention.

  According to the electronic apparatus of the present invention, since the above-described electro-optical device of the present invention is provided, good alignment characteristics can be obtained. As a result, various types of electronic devices such as projection display devices capable of displaying high-quality images, mobile phones, electronic notebooks, word processors, viewfinder type or monitor direct view type video tape recorders, workstations, videophones, POS terminals, touch panels, etc. Equipment can be realized.

  The effect | action and other gain of this invention are clarified from the form for implementing demonstrated below.

It is the top view which looked at the liquid crystal device concerning the embodiment of the present invention from the counter substrate side with each component formed on the TFT array substrate. It is the HH 'sectional view taken on the line of FIG. It is process sectional drawing which shows 1 process of the manufacturing method of the liquid crystal device which concerns on embodiment of this invention. It is a table | surface which shows the relationship between the structure of a liquid, and the propriety of the pretilt angle control at the time of alignment film formation. FIG. 4 is an enlarged process cross-sectional view showing a part of FIG. 3 in an enlarged manner. It is a characteristic view which shows an example of the relationship between a spin time and a pretilt angle. It is a characteristic view which shows an example of the relationship between a spin time and the shift | offset | difference of an electrical property. It is a top view which shows the structure of the projector which is an example of the electronic device to which the electro-optical apparatus is applied.

  Hereinafter, embodiments of an electro-optical device manufacturing method, an electro-optical device, and an electronic apparatus according to the invention will be described with reference to the drawings. In the following drawings, the scales are different for each layer and each member so that each layer and each member can be recognized on the drawing.

<Electro-optical device>
An embodiment of an electro-optical device according to the invention will be described with reference to FIGS. 1 and 2. In the present embodiment, as an example of an electro-optical device, an active matrix driving type liquid crystal device with a built-in driving circuit is taken as an example.

  The overall configuration of the liquid crystal device according to the present embodiment will be described with reference to FIGS. FIG. 1 is a plan view of the liquid crystal device according to the present embodiment as viewed from the side of the counter substrate together with each component formed on a TFT (Thin Film Transistor) array substrate, and FIG. -H 'sectional view.

  1 and 2, in the liquid crystal device 100 according to the present embodiment, the TFT array substrate 10 and the counter substrate 20 are arranged to face each other. The TFT array substrate 10 is made of a substrate such as a quartz substrate, a glass substrate, or a silicon substrate, and the counter substrate 20 is made of a substrate such as a quartz substrate or a glass substrate. A liquid crystal layer 50 is sealed between the TFT array substrate 10 and the counter substrate 20, and the TFT array substrate 10 and the counter substrate 20 are sealed by a sealing material 52 provided in a seal region located around the image display region 10a. They are glued together.

  The sealing material 52 is made of, for example, an ultraviolet curable resin, a thermosetting resin, or an ultraviolet / heat combination type curable resin for bonding the two substrates, and is applied to the TFT array substrate 10 in the manufacturing process, and then irradiated with ultraviolet rays. And cured by heating or the like. In the sealing material 52, a gap material such as glass fiber or glass beads for dispersing the distance (ie, gap) between the TFT array substrate 10 and the counter substrate 20 to a predetermined value is dispersed. Note that the gap material may be arranged in the image display region 10a or a peripheral region located around the image display region 10a in addition to or instead of the material mixed in the seal material 52.

  In FIG. 1, a light-shielding frame light-shielding film 53 that defines the image display region 10 a is provided on the counter substrate 20 side in parallel with the inside of the seal region where the sealing material 52 is disposed. However, part or all of the frame light shielding film 53 may be provided as a built-in light shielding film on the TFT array substrate 10 side.

  A data line driving circuit 101 and an external circuit connection terminal 102 are provided along one side of the TFT array substrate 10 in a region located outside the sealing region in which the sealing material 52 is disposed in the peripheral region. The sampling circuit 7 is provided so as to be covered with the frame light shielding film 53 on the inner side of the seal region along the one side. The scanning line driving circuit 104 is provided in a frame area inside the seal area along two sides adjacent to the one side so as to be covered with the frame light shielding film 53.

  On the TFT array substrate 10, vertical conduction terminals 106 for connecting the two substrates with the vertical conduction material 107 are arranged in regions facing the four corner portions of the counter substrate 20. Thus, electrical conduction can be established between the TFT array substrate 10 and the counter substrate 20. Further, a lead wiring 90 for electrically connecting the external circuit connection terminal 102 to the data line driving circuit 101, the scanning line driving circuit 104, the vertical conduction terminal 106, and the like is formed.

  In FIG. 2, on the TFT array substrate 10, a laminated structure in which wirings such as pixel switching transistors, scanning lines, and data lines as drive elements are formed is formed. Although the detailed structure of this laminated structure is not shown in FIG. 2, pixel electrodes 9a made of a transparent material such as ITO (Indium Tin Oxide) are provided on the laminated structure in a predetermined pattern for each pixel. It is formed in an island shape.

  The pixel electrode 9a is formed in the image display region 10a on the TFT array substrate 10 so as to face a counter electrode 21 described later. On the surface of the TFT array substrate 10 facing the liquid crystal layer 50, that is, on the pixel electrode 9a, an alignment film 16 is formed so as to cover the pixel electrode 9a.

  A light shielding film 23 is formed on the surface of the counter substrate 20 facing the TFT array substrate 10. For example, the light shielding film 23 is formed in a lattice shape when viewed in plan on the facing surface of the facing substrate 20. In the counter substrate 20, a non-opening area is defined by the light shielding film 23, and an area partitioned by the light shielding film 23 is an opening area through which light emitted from, for example, a projector lamp or a direct viewing backlight is transmitted. The light shielding film 23 may be formed in a stripe shape, and the non-opening region may be defined by the light shielding film 23 and various components such as data lines provided on the TFT array substrate 10 side.

  On the light shielding film 23, a counter electrode 21 made of a transparent material such as ITO is formed so as to face the plurality of pixel electrodes 9a. In order to perform color display in the image display region 10a on the light shielding film 23, a color filter (not shown in FIG. 2) may be formed in a region including a part of the opening region and the non-opening region. An alignment film 22 is formed on the counter electrode 21 on the counter surface of the counter substrate 20.

  In addition to the data line driving circuit 101, the scanning line driving circuit 104, the sampling circuit 7, etc., a plurality of data lines are pre-set at a predetermined voltage level on the TFT array substrate 10 shown in FIGS. A precharge circuit that supplies a charge signal prior to an image signal, an inspection circuit for inspecting the quality, defects, and the like of the liquid crystal device during manufacture or at the time of shipment may be formed.

  The “alignment film 16” and the “alignment film 22” according to the present embodiment are examples of the “alignment film” according to the present invention. The “liquid crystal” according to the present embodiment is an example of the “electro-optical material” according to the present invention.

<Method of manufacturing electro-optical device>
An embodiment of a method for manufacturing an electro-optical device according to the present invention will be described with reference to FIGS. Here, a process for forming the alignment film 16 on the TFT array substrate 10 will be described with reference to FIG. FIG. 3 is a process cross-sectional view showing one process of the manufacturing method of the liquid crystal device according to the present embodiment.

  In FIG. 3, the TFT array substrate 10 in which the pixel electrode 9 a is formed on the laminated structure in which the pixel switching transistors, the scanning lines, the data lines, and the like are formed is placed on the spin coater 300. After that, the TFT array substrate 10 is rotated at, for example, 3000 rpm (rotation per minute) by the spin coater 300, and a liquid material containing a diamine-based thermal cross-linking agent is applied onto the TFT array substrate 10 to form a liquid. A body layer 200 is formed.

  Next, for example, the TFT array substrate 10 is heated to 70 to 180 ° C. while the rotation of the TFT array substrate 10 on which the liquid material layer 200 is formed is stopped (that is, the rotation of the spin coater 300 is stopped). Then, the liquid material layer 200 is dried at a high temperature to form the alignment film 16.

  The “liquid body” according to the present embodiment includes a diamine-based thermal crosslinking agent, polyimide, γ-butyrolactone, N-methylpyrrolidone, and butyl cellosolve. Here, γ-butyrolactone and N-methylpyrrolidone as the main solvent occupy 90% or more of the liquid, and butyl cellosolve as the leveling agent occupies within 5% of the liquid.

  Here, the relationship between the configuration of the liquid material and whether or not the pretilt angle control is possible when forming the alignment film will be described with reference to FIG. As shown in FIG. 4, when the liquid material contains a thermal cross-linking agent, and the polyimide concentration in the liquid material (ie, the solid content concentration) is 4% or less, the pretilt is formed when the alignment film is formed. It can be seen that the angle can be controlled. For this reason, in this embodiment, it sets so that the density | concentration of the polyimide in a liquid may be 4% or less.

  Next, the liquid layer 200 formed on the TFT array substrate 10 will be described with reference to FIG. FIG. 5 is an enlarged cross-sectional view showing a part of FIG. 3 in an enlarged manner.

  As shown in FIG. 5A, when the solvent contained in the liquid material layer 200 is relatively large, additives such as a main chain of polyimide and a thermal crosslinking agent contained in the liquid material layer 200 are dispersed in the solvent. is doing. In this state, when the liquid material layer 200 is dried at a high temperature, the inventors have found that the alignment of the polyimide can be suppressed and the alignment film 16 having uniform alignment characteristics can be formed.

  On the other hand, as shown in FIG. 5B, when the solvent contained in the liquid material layer 200 is relatively small, the polyimide aggregates in the process of decreasing the solvent, and the polyimide main chain and the additive are unevenly distributed. . For this reason, in this state, when the liquid layer 200 is dried at a high temperature, the inventors have found that the alignment film 16 having non-uniform alignment characteristics is formed due to the disturbance of the main chain of the polyimide. is doing.

  For this reason, in this embodiment, as shown in FIG. 5A, the liquid material layer 200 can be dried at a high temperature in a state where a relatively large amount of solvent remains in the liquid material layer 200. The time for rotating the TFT array substrate 10 when forming 200 is set to a relatively short time, such as 90 to 120 seconds. As a result, the alignment film 16 having uniform alignment characteristics can be formed by the manufacturing method according to this embodiment.

  Note that the alignment film 22 having uniform alignment characteristics can be formed by forming the alignment film 22 on the counter substrate 20 by a method similar to the manufacturing method described above.

  Next, the characteristics of the alignment film 16 (or 22) formed as described above will be described with reference to FIGS. FIG. 6 is a characteristic diagram showing an example of the relationship between the spin time and the pretilt angle, and FIG. 7 is a characteristic diagram showing an example of the relationship between the spin time and the deviation in electrical characteristics.

  As shown in FIG. 6, when the liquid layer 200 is dried at a high temperature with a relatively large amount of solvent remaining in the liquid layer 200, the pretilt angle can be adjusted within a range of 10 to 15 degrees. Recognize.

  Further, when the liquid layer 200 is dried at a high temperature in a state where a relatively large amount of the solvent remains in the liquid layer 200, the additives contained in the liquid layer 200 are distributed almost uniformly. For this reason, the nonuniformity of the adsorption balance of impurity ions in the liquid crystal device 100 (see FIG. 1) can be improved. As a result, a shift in electrical characteristics of the liquid crystal device 100 (that is, a Vcom shift) can be suppressed (see FIG. 7), and the highly reliable liquid crystal device 100 can be provided.

  In this embodiment, in particular, since the pretilt angle can be controlled when forming the alignment film (see FIG. 4), display unevenness and stripe unevenness due to pretilt angle control by adjusting the rubbing intensity can be prevented. In addition, since the pretilt angle can be controlled when forming the alignment film, the process margin can be widened.

  Furthermore, in this embodiment, since a relatively low pretilt angle can be realized when forming the alignment film (see FIG. 6), it is possible to prevent the alignment film from being scraped due to strong rubbing for realizing the low pretilt angle. . As a result, the deterioration of display quality can be suppressed, which is very advantageous in practice.

<Electronic equipment>
Next, a case where the liquid crystal device 100 described above is applied to a projector which is an example of an electronic device will be described with reference to FIG. The liquid crystal device 100 described above is used as a light valve of a projector. FIG. 8 is a plan view showing a configuration example of the projector.

  As shown in FIG. 8, a projector 1100 includes a lamp unit 1102 made of a white light source such as a halogen lamp. The projection light emitted from the lamp unit 1102 is separated into three primary colors of RGB by four mirrors 1106 and two dichroic mirrors 1108 arranged in the light guide 1104, and serves as a light valve corresponding to each primary color. The light enters the liquid crystal panels 1110R, 1110B, and 1110G.

  The configurations of the liquid crystal panels 1110R, 1110B, and 1110G have the same configuration as that of the above-described liquid crystal device 100, and are driven by R, G, and B primary color signals supplied from the image signal processing circuit, respectively. . The light modulated by these liquid crystal panels enters the dichroic prism 1112 from three directions. In this dichroic prism 1112, R and B light is refracted at 90 degrees, while G light travels straight. Accordingly, as a result of the synthesis of the images of the respective colors, a color image is projected onto the screen or the like via the projection lens 1114.

  Here, paying attention to the display images by the liquid crystal panels 1110R, 1110B, and 1110G, the display images by the liquid crystal panels 1110R and 1110B need to be horizontally reversed with respect to the display images by the liquid crystal panel 1110G.

  Since light corresponding to the primary colors R, G, and B is incident on the liquid crystal panels 1110R, 1110B, and 1110G by the dichroic mirror 1108, it is not necessary to provide a color filter.

  In addition to the electronic device described with reference to FIG. 8, a mobile personal computer, a mobile phone, an LCD TV, a viewfinder type or a monitor direct-view type video tape recorder, a car navigation device, a pager, and an electronic notebook , Calculators, word processors, workstations, videophones, POS terminals, devices with touch panels, and the like. Needless to say, the present invention can be applied to these various electronic devices.

  The present invention is not limited to the above-described embodiments, and various modifications can be made as appropriate without departing from the spirit or concept of the invention that can be read from the claims and the entire specification. A manufacturing method, an electro-optical device, and an electronic apparatus are also included in the technical scope of the present invention.

  DESCRIPTION OF SYMBOLS 10 ... TFT array substrate, 16, 22 ... Alignment film, 20 ... Counter substrate, 50 ... Liquid crystal layer, 100 ... Liquid crystal device, 200 ... Liquid layer, 300 ... Spin coat device

Claims (5)

A method of manufacturing an electro-optical device including a pair of substrates each having an alignment film that gives a predetermined pretilt angle to an electro-optical material,
On each of the pair of substrates, an application step of applying a liquid containing a thermal crosslinking agent by a spin coating method;
And a drying step of forming the alignment film by drying the applied liquid material at a high temperature.   2. The method of manufacturing an electro-optical device according to claim 1, wherein, in the coating step, a time for rotating each of the pair of substrates by a spin coating method is 120 seconds or less.   3. The method of manufacturing an electro-optical device according to claim 1, wherein the weight of the polymer material contained in the liquid is 4% or less with respect to the weight of the liquid. A pair of substrates each formed with an alignment film that gives a predetermined pretilt angle to the electro-optic material;
The alignment film is formed by applying a liquid material containing a thermal crosslinking agent on each of the pair of substrates by a spin coating method, and then drying the applied liquid material at a high temperature. Electro-optical device characterized.   An electronic apparatus comprising the electro-optical device according to claim 4.

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