JP2011158531A - Method for manufacturing liquid crystal device - Google Patents

Abstract

Display defects such as image sticking in a liquid crystal device are prevented.
A method of manufacturing a liquid crystal device is a method of manufacturing a liquid crystal device (100) including an element substrate (10) and a counter substrate (20) disposed to face the element substrate. The manufacturing method includes forming a counter electrode (21) containing ITO on a counter substrate, and forming a pixel electrode (9a) containing ITO on the element substrate. A process. In the pixel electrode formation step, the difference between the oxygen flow rate in the pixel electrode formation step and the oxygen flow rate in the counter electrode formation step is changed according to the aperture ratio of the element substrate.
[Selection] Figure 6

Description

  The present invention relates to a technical field of a manufacturing method of a liquid crystal device.

  In a liquid crystal device manufactured by this type of method, it is possible to prevent display defects such as image sticking. For example, in Patent Document 1, after forming a pixel electrode and a counter electrode on a TFT (Thin Film Transistor) substrate and a counter substrate, respectively, the pixel electrode and the counter electrode are heated while heating the TFT substrate and the counter substrate in a reducing atmosphere. A method of forming an inorganic alignment film on the substrate is disclosed.

  Alternatively, in Patent Document 2, the pixel electrode and the counter electrode are formed on the TFT substrate and the counter substrate, respectively, and then the TFT substrate and the counter substrate are heated in a chlorine-based gas atmosphere while the pixel electrode and the counter substrate are heated. A method of removing hydroxyl groups on a pixel electrode and a counter electrode by performing a hydroxyl removal treatment is disclosed. Alternatively, Patent Document 3 discloses a method of performing plasma treatment on an electrode formed on either the TFT substrate or the counter substrate after electrodes are formed on the TFT substrate and the counter substrate, respectively.

JP 2008-203712 A JP 2008-209692 A JP 2008-185669 A

  However, according to the background art described above, it is technically necessary to perform surface treatment such as heat treatment, dehydroxylation treatment, and plasma treatment after electrode formation, and the manufacturing process may be relatively complicated. There is a problem.

  The present invention has been made in view of the above problems, for example, and an object of the present invention is to propose a method for manufacturing a liquid crystal device capable of preventing display defects such as image sticking by a relatively simple method.

  In order to solve the above-described problem, a method for manufacturing a liquid crystal device according to the present invention is a method for manufacturing a liquid crystal device including an element substrate and a counter substrate disposed to face the element substrate. A counter electrode forming step of forming a counter electrode containing ITO, and a pixel electrode forming step of forming a pixel electrode containing ITO on the element substrate, wherein the pixel electrode The difference between the oxygen flow rate in the forming step and the oxygen flow rate in the counter electrode forming step is changed according to the aperture ratio of the element substrate.

  According to the method for manufacturing a liquid crystal device of the present invention, the method is a method for manufacturing a liquid crystal device including an element substrate and a counter substrate disposed to face the element substrate. In the counter electrode forming step, a counter electrode containing ITO (Indium Tin Oxide) is formed on the counter substrate. In the pixel electrode formation step, a pixel electrode containing ITO is formed on the element substrate.

  In the present invention, in particular, in the pixel electrode formation step, the difference between the oxygen flow rate in the pixel electrode formation step and the oxygen flow rate in the counter electrode formation step (that is, the oxygen flow rate in the pixel electrode formation step−the oxygen flow rate in the counter electrode formation step) is It is changed according to the aperture ratio of the element substrate. Specifically, for example, the difference is changed so as to increase as the aperture ratio of the element substrate increases.

  Each of the oxygen flow rate in the pixel electrode formation step and the oxygen flow rate in the counter electrode formation step is preferably not more than a predetermined value such as 2 sccm (standard cc / min), and is preferably as small as possible. Here, the “predetermined value” according to the present invention may be set, for example, as a value that does not cause liquid crystal light deterioration when the liquid crystal device manufactured by the manufacturing method is irradiated with light.

  According to the inventor's research, the following matters have been found. That is, there is a negative correlation between the difference between the oxygen flow rate at the time of forming the pixel electrode and the oxygen flow rate at the time of forming the counter electrode, and the optimum variation amount of Vcom. On the other hand, when the oxygen flow rate is fixed to an arbitrary value, there is a positive correlation between the aperture ratio of the element substrate and the optimum amount of fluctuation of Vcom. Therefore, there is a positive correlation between the aperture ratio of the element substrate and the difference at which the optimum Vcom does not vary. For this reason, if the said difference is set according to the aperture ratio of an element substrate, the optimal fluctuation | variation of Vcom can be suppressed.

  As described above, in the present invention, in the pixel electrode formation step, the difference between the oxygen flow rate in the pixel electrode formation step and the oxygen flow rate in the counter electrode formation step is changed according to the aperture ratio of the element substrate. For this reason, the optimal fluctuation | variation of Vcom can be suppressed. As a result, it is possible to prevent the occurrence of, for example, flicker and burn-in due to the optimal fluctuation of Vcom. In addition, after the pixel electrode and the counter electrode are formed, post-processing is not required for the pixel electrode and the counter electrode, which is very advantageous in practice.

  As a result, according to the method for manufacturing a liquid crystal device of the present invention, display defects such as burn-in can be prevented by a relatively simple method.

  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 the one part process of the manufacturing method of the liquid crystal device which concerns on embodiment of this invention. The experimental values showing an example of the relationship between the variation amount of delta O.D. ₂ flow rate and optimum Vcom. This is an experimental value showing an example of the relationship between the aperture ratio of the TFT array substrate and the variation rate of the optimum Vcom. This is an experimental value showing an example of the relationship between the aperture ratio of the TFT array substrate and the ΔO ₂ flow rate at which the optimum Vcom does not vary. It is an experimental value which shows an example of the relationship between an external DC voltage and the variation | change_quantity of optimal Vcom. It is an experimental value which shows an example of the relationship between an oxygen flow rate and inclination.

  Hereinafter, embodiments of a method for manufacturing a liquid crystal device according to the present 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 confirmed on the drawing.

<Liquid crystal device>
First, an embodiment of a liquid crystal device manufactured by the method for manufacturing a liquid crystal device according to the present invention will be described with reference to FIGS. In this embodiment, an active matrix driving type liquid crystal device with a built-in driving circuit is taken as an example of the liquid crystal device.

  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 a liquid crystal device according to an embodiment of the present invention as viewed from the side of a counter substrate together with each component formed on a TFT array substrate, and FIG. It is line sectional drawing.

  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 as an example of the “element substrate” according to the present invention includes a substrate such as a quartz substrate, a glass substrate, and a silicon substrate, and the counter substrate 20 includes, for example, a substrate such as a quartz substrate and a glass substrate. Become. 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 containing ITO are formed in an island shape in a predetermined pattern for each pixel on the laminated structure. Yes.

  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 that transmits light emitted from, for example, a projector lamp or a direct viewing backlight. 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 containing ITO is formed 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.

<Manufacturing method of substrate for liquid crystal device>
Next, an embodiment of a liquid crystal device according to the present invention will be described with reference to FIGS. FIG. 3 is a process cross-sectional view illustrating a part of the process of the manufacturing method of the liquid crystal device according to the present embodiment.

  In the counter electrode forming step, the counter electrode 21 containing ITO is formed on the counter substrate 20 (see FIG. 3A). In the pixel electrode forming step, for example, ITO is formed on the TFT array substrate 10 on which a laminated structure (not shown) in which wirings such as pixel switching transistors, scanning lines, and data lines as drive elements are formed is formed. Are formed so as to face the counter electrode 21 (see FIG. 3B).

  Here, in the present embodiment, the oxygen flow rate when the pixel electrode 9a is formed (that is, when the ITO film is formed on the TFT array substrate 10) and the counter electrode 21 are formed (that is, the counter electrode 21a). The difference from the oxygen flow rate when the ITO film is formed on the substrate 20 is changed according to the aperture ratio of the TFT array substrate 10. In addition, the oxygen flow rate when the pixel electrode 9a is formed and the oxygen flow rate when the counter electrode 21 is formed are set to be as small as possible at 2 sccm or less.

According to the inventor's research, the following matters have been found. That is, (i) as shown in FIG. 4, a ΔO ₂ flow rate (that is, a TFT array) that is a difference between an oxygen flow rate at the time of ITO film formation on the TFT array substrate 10 and an oxygen flow rate at the time of ITO film formation on the counter substrate 20. There is a negative correlation between the oxygen flow rate at the time of ITO film formation on the substrate 10 -the oxygen flow rate at the time of ITO film formation on the counter substrate 20) and the variation amount of the optimum Vcom. FIG. 4 is an experimental value showing an example of the relationship between the ΔO ₂ flow rate and the variation amount of the optimum Vcom.

  (Ii) As shown in FIG. 5, when the oxygen flow rate is fixed, there is a positive correlation between the aperture ratio of the TFT array substrate 10 and the variation amount of the optimum Vcom. FIG. 5 is an experimental value showing an example of the relationship between the aperture ratio of the TFT array substrate and the variation rate of the optimum Vcom.

(Iii) From (i) and (ii) above, there is a positive correlation between the aperture ratio of the TFT array substrate 10 and the ΔO ₂ flow rate at which the optimum Vcom does not vary (see FIG. 6). Therefore, based on the relationship as shown in FIG. 6, the optimum Vcom variation is set by setting the oxygen flow rate when the ITO film is formed on the TFT array substrate 10 according to the aperture ratio of the TFT array substrate 10. Can be suppressed. FIG. 6 is an experimental value showing an example of the relationship between the aperture ratio of the TFT array substrate and the ΔO ₂ flow rate at which the optimum Vcom does not vary.

  (Iv) As shown in FIG. 7, when a direct current (DC) voltage is applied to the liquid crystal device from the outside, the variation of the optimum Vcom occurs. FIG. 7 is an experimental value showing an example of the relationship between the external DC voltage and the variation amount of the optimum Vcom.

  (V) There is a positive correlation between the slope of the straight line in the relationship as shown in FIG. 7 and the oxygen flow rate during the ITO film formation on the TFT array substrate 10 or the counter substrate 20 (see FIG. 8). . For example, it is desirable in practice that the optimum Vcom does not fluctuate even when an unintended external DC voltage such as noise is applied to the liquid crystal device (that is, it is desirable that the slope of the straight line in FIG. 7 is small). Therefore, it is desirable that the oxygen flow rate during the ITO film formation on the TFT array substrate 10 and the counter substrate 20 is as small as possible. FIG. 8 is an experimental value showing an example of the relationship between the oxygen flow rate and the slope.

  (Vi) When the oxygen flow rate exceeds 2 sccm, when the liquid crystal device is irradiated with light, liquid crystal photodegradation due to chemical interaction between the light and the liquid crystal is promoted, so the oxygen flow rate is 2 sccm or less. Is required.

  (Vii) From (v) and (vi) above, by reducing the oxygen flow rate during the ITO film formation on each of the TFT array substrate 10 and the counter substrate 20 as small as possible at 2 sccm or less, photodegradation of the liquid crystal is prevented. The influence caused by external DC voltage such as noise can be suppressed.

  In the present embodiment, as described above, the difference between the oxygen flow rate when the pixel electrode 9 a is formed and the oxygen flow rate when the counter electrode 21 is formed is changed according to the aperture ratio of the TFT array substrate 10. The Furthermore, the oxygen flow rate when the pixel electrode 9a is formed and the oxygen flow rate when the counter electrode 21 is formed are set to be as small as possible at 2 sccm or less.

  For this reason, the liquid crystal device 100 manufactured by the manufacturing method according to the present embodiment can suppress the variation of the optimum Vcom. As a result, it is possible to prevent the occurrence of flicker, burn-in, and the like caused by fluctuations in the optimum Vcom. In addition, after the pixel electrode 9a and the counter electrode 21 are formed, the pixel electrode 9a and the counter electrode 21 do not require post-treatment such as heat treatment, dehydroxylation treatment, and plasma treatment. Is advantageous.

  The present invention is not limited to the above-described embodiment, and can be appropriately changed without departing from the gist or concept of the invention that can be read from the claims and the entire specification, and manufacture of a liquid crystal device with such a change. The method is also included in the technical scope of the present invention.

  9a ... Pixel electrode, 10 ... TFT array substrate, 20 ... Counter substrate, 21 ... Counter electrode, 100 ... Liquid crystal device

Claims (3)

A manufacturing method of a liquid crystal device comprising an element substrate and a counter substrate disposed opposite to the element substrate,
A counter electrode forming step of forming a counter electrode comprising ITO on the counter substrate;
A pixel electrode forming step of forming a pixel electrode containing ITO on the element substrate;
In the pixel electrode formation step, the difference between the oxygen flow rate in the pixel electrode formation step and the oxygen flow rate in the counter electrode formation step is changed according to the aperture ratio of the element substrate. Method.   The method of manufacturing a liquid crystal device according to claim 1, wherein the difference is changed so as to increase as the aperture ratio increases.   The method for manufacturing a liquid crystal device according to claim 1, wherein an oxygen flow rate in the counter electrode formation step and an oxygen flow rate in the pixel electrode formation step are both equal to or less than a predetermined value.

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