JP5437107B2 - Plate member having coating film, liquid crystal display device, and manufacturing method thereof - Google Patents

Description

  The present invention relates to a plate-like member having a coating film, a liquid crystal display device, and a method for manufacturing them.

  As a method for forming a coating film on a plate-like member, there are various methods such as dipping, brush coating, doctor blade, bar coating, slit coating, spin coating, spray coating, ink jet, and dispenser.

  There is a demand for a coating film having a uniform thickness. For example, the optical film is often required to have a certain thickness. In the vertical alignment liquid crystal display device, a negative uniaxial optical anisotropic film (-c plate) is used as an optical compensation film. This optical compensation film is desired to have a negative uniaxial optical anisotropy of a predetermined magnitude that compensates for the positive uniaxial optical anisotropy of the vertically aligned liquid crystal layer. If the film thickness is distributed in the plane, the optical function also has a distribution in the plane.

  When a liquid-phase coating solution is applied to a plate-like member and dried, the central portion can be made to have a uniform thickness, but a thickness distribution occurs in the peripheral portion. For example, the peripheral portion is thicker than the central portion. In this case, the movement of the coating liquid from the central part to the peripheral part can be considered as one possible cause of the film thickness distribution.

  JP-A-2005-224754 discloses that a film resin material is cast on a support, the film resin layer is peeled off from the support in the middle of drying, and a hard coat layer is applied to the film surface in the middle of drying. A method for producing an optical film is proposed in which the hard coat layer is cured by energy rays and then the film is further dried.

JP 2005-224754 A

  A coating film having a more uniform thickness distribution is formed on the plate member. An increase in film thickness at the periphery of the plate member is suppressed. An optical film having uniform optical properties is manufactured. A liquid crystal display device including an optical film is provided.

According to one aspect of the present invention,
A step of applying a water-repellent film to the entire circumference of the side surface of the plate-like member that is hydrophilic and has a surface and a side surface surrounding the surface ;
Applying a hydrophilic coating solution to the entire surface of the plate-like member to form a coating film;
Only including, above the coating film and the water-repellent film in contact only at the boundary between the side surface and the surface, a manufacturing method of the plate-like member having a coating film is provided.

According to another aspect of the invention,
A pair of plate-like member surfaces that are hydrophilic and have a surface and side surfaces, a patterned transparent electrode, and a vertical alignment film that covers a predetermined range of the plate-like member are sequentially formed, and the vertical alignment film is opposed to each other. A step of sandwiching the liquid crystal layer to create a liquid crystal cell;
Applying a water-repellent film to the entire side surface surrounding the outer surface of one of the plate-like members;
A step of applying a hydrophilic coating liquid on the entire outer surface of a plate-like member having a water-repellent film coated on the side surface by a droplet spray coating method to form a coated film, the coating film and the water-repellent film Is in contact with only the boundary between the outer surface and the side surface, and
A method of manufacturing a liquid crystal display device including the above is provided.

  A coating film having a uniform thickness distribution is provided. A liquid crystal display device provided with a coating film having uniform optical characteristics is provided.

1AP and 1BP are plan views showing a method for producing a coating film on a plate-like member according to the embodiment. FIGS. 1AV and 1BV are plates showing a method for producing a coating film on the plate-like member according to the embodiment. It is sectional drawing of a member. 2A and 2B are a cross-sectional view of a plate-like member schematically showing a state where a coating film manufactured according to an example is partially removed and a film thickness distribution is measured, and a graph showing the measured film thickness distribution. . 3A and 3B are sectional views of a plate-like member schematically showing a state in which a coating film manufactured according to a comparative example is partially removed and a film thickness distribution is measured, and a graph showing the measured film thickness distribution. is there. FIG. 4 is a cross-sectional view of a liquid crystal display device having a vertically aligned liquid crystal layer. 5A and 5B are a side view and a plan view showing spray coating on a plate-like member.

  The process of forming a coating film on a plate-like member will be described by taking spray coating as an example.

  FIG. 5A shows a state in which a coating solution serving as an optical film material is applied to the surface of a plate-like member 1 such as a glass substrate. The spray nozzle 11 of the spray coating apparatus 10 is disposed above the plate-like member 1, and the plate-like member 1 is scanned while spraying the coating liquid 12 to form the coating film 2. Various spray coating apparatuses are commercially available. For example, a DC series spray coater available from Sanmei Electronics Co., Ltd. can be used.

  FIG. 5B shows a scanning trajectory T of the spray nozzle above the plate-like member 1. Scanning across the plate-like member 1 to be applied, crossing the plate-like member 1 in one direction, folding back at a constant pitch (interval), crossing the plate-like member in the opposite direction, and folding back at a constant pitch repeat. The coating film 2 is formed so as to project a predetermined width outward from the plate-like member 1. The coating solution for the optical film material is hydrophilic and is considered to be familiar with the surface of a hydrophilic glass substrate or the like.

  If the surface of the plate-like member is flat, it is considered that the coating liquid layer has a flat surface and a uniform liquid layer thickness in the central part excluding the peripheral part. At the end of the liquid layer, the outer surface is in contact with air, and the liquid layer thickness will change due to the influence of surface tension.

  The inventor considered applying a water-repellent material to the side surface of the plate-like member.

  1AP-1BP and 1AV-1BV show a method of applying a hydrophilic liquid layer material to a hydrophilic plate-like member according to an embodiment. As shown in FIGS. 1AP and 1AV, a water repellent material 3 is applied to the side surface of a plate-like member 1 having a hydrophilic surface such as a glass substrate. The side surface of the plate-like member 1 is substantially perpendicular to the surface, and the boundary with the surface forms a sharp ridgeline.

  In the actually created example, a blue plate glass substrate having a thickness of about 0.7 mm and a size of 150 mm × 150 mm is used as the plate-like member 1, and a Teflon-based water-repellent material 3 is formed on the side thereof with a needle tip of a syringe for a syringe. Applied. After coating, it was placed in an oven at about 120 ° C. for about 30 minutes and dried. Thereafter, the glass substrate 1 was ultrasonically washed in pure water + neutral detergent (about 3 wt%) for about 15 minutes and washed with water. The dried water-repellent film 3 is applied to the side surface of the plate member 1 with a thickness of several μm to several tens of μm.

  As shown in FIGS. 1BP and 1BV, a hydrophilic material film 2 is applied to the surface of the plate-like member 1 using a spray coater. In the example, an optical material film (viscosity: 60-150 cps, 1.6 mL), which is a material for forming a negative uniaxial optical anisotropic film, was applied by spraying.

  The film thickness distribution was measured in a sample in which an optical film was actually created.

  As shown in FIG. 2A, the optical film 2x on the glass substrate 1 was partially removed to expose the surface of the glass substrate 1. The height of the surface of the glass substrate 1 and the surface of the optical film 2 was measured using a stylus thickness meter (Dektak 3030 manufactured by ULVAC). Since it is a stylus type, the height measurement in a portion where the surface height changes sharply, such as a corner, lacks accuracy.

  FIG. 2B is a graph showing the measurement results. The horizontal axis indicates the distance (μm) on the glass substrate, and the vertical axis indicates the height (Å). The glass substrate surface is shown calibrated to zero height. A width of about 4.2 mm to the edge of the glass substrate is measured. The height (film thickness) at the left end point S is about 4.5 μm, the height decreases almost linearly toward the right end direction, and the height (film thickness) at the right end E is about 4.1 μm. It is. After that, the height has decreased sharply. Even if the film thickness at the edge is about 4.0 μm, the film thickness at the edge is reduced by about 0.5 μm at a distance of about 4.2 mm. mm. The rise of the optical film at the periphery of the plate member is not observed at all. For comparison, a sample in which the water repellent material was not applied to the side surface of the glass substrate was also prepared.

  FIG. 3A shows the configuration of the comparative example. An optical film 2 is formed on the surface of the blue plate glass substrate 1, and a part 2x is removed. It was created using the same process as the example except that the water repellent material was not applied to the side surface of the glass substrate 1.

  FIG. 3B is a graph showing the measurement results of the film thickness distribution. As in FIG. 2B, the horizontal axis indicates the distance (μm) on the glass substrate, and the vertical axis indicates the height (Å). A height of 0 indicates the glass substrate surface. The height (film thickness) at the point S is about 5.0 μm, and gradually increases toward the end, indicating the swell of the optical film at the periphery of the glass substrate. The height at the peak P is about 6.0 μm, and the film thickness rises to about 1 μm. Thereafter, the height decreases, and the end E shows the curvature. The distance between the SPs is about 3.2 mm, which is about 0.3 μm / mm when indicated by a gradient.

  Comparing the results of FIGS. 2B and 3B, it can be seen that by applying the water repellent material to the side surface of the glass substrate, the rise of the film thickness at the edge of the glass substrate is remarkably suppressed and the gradient is reduced. A film having a more uniform film thickness distribution can be formed.

  The reason why such a difference occurs in the film thickness distribution of the hydrophilic coating film formed on the entire main surface of the plate-like member depending on whether or not a water-repellent material is applied to the side of the plate-like member is unknown. There is an obvious difference in the film thickness distribution of the hydrophilic coating film formed on the entire main surface of the member.

  Looking for the difference in configuration, it is determined whether or not the hydrophilic coating film applied to the main surface of the plate-like member is in contact with the water-repellent material film formed on the side surface of the plate-like member at the end. Let's go. When the water repellent material is not applied to the side surface of the plate-like member, the interface between the main surface of the plate-like member and the hydrophilic coating film applied thereon is released to the air at the coating film end. When the water-repellent material is applied to the side surface of the plate-like member, the interface between the main surface of the plate-like member and the hydrophilic coating film applied thereon is the water-repellent material film applied to the side surface of the plate-like member at the end of the coating film. It is thought to touch. In the above embodiment, the water-repellent material is applied to the side surface of the plate-like member and hardly exists on the upper surface of the plate-like member. The coating film applied to the upper surface of the plate-like member and the water-repellent film applied to the side surface of the plate-like member do not form a surface contact, and the boundary between the coating film and the water-repellent film, that is, the upper surface and side surfaces of the plate-like member It is considered that only the linear contact that contacts only at the corners as the boundary.

  The difference in whether the film thickness rises around the coating film depending on whether the interface between the plate-like member and the coating film formed on it is released into the air or terminated with a water-repellent material film May also occur. If the movement of the coating liquid material is dominant at the interface, the movement of the coating film material may be controlled depending on the state of the interface edge, and whether or not the film thickness rises may be controlled. . Then, the film thickness distribution at the periphery of the coating film is allowed when the interface edge between the coating film and the base is released into the air, and the interface edge can be terminated with a water repellent material. In other words, it can be interpreted that the rise of the film thickness distribution can be avoided. It is considered that the end of the interface between the coating film and the plate-like member being linearly terminated by the water-repellent material is effective in suppressing the film thickness rise around the coating film.

  In the example described above, a glass substrate having a thickness of about 0.7 mm is used as the plate-like member. However, the plate-like member may have any hydrophilic surface and can be coated with a water-repellent film on the side surface. I will. In order to apply the water repellent film, the thickness is preferably 0.5 mm or more. In the experiment, the water-repellent film was applied with a syringe, but at the time of mass production, the water-repellent film can be easily applied to the side surface of the plate-like member by using a stamp table or a sponge with hardness to soak the water-repellent material. Will.

  The film applied to the plate-like member surface is not limited to an optical film. If it is a hydrophilic material, the effect of uniformizing the film thickness applied to the surface of the plate-like member will be obtained. In addition, the effect of uniformizing the film thickness applied to the main surface of the plate-like member is considered to be obtained by the water-repellent film applied to the side surface of the plate-like member, and does not depend on the method of applying the film applied to the surface. I will. In addition to spray coating, various methods such as dipping, brush coating, doctor blade, bar coating, slit coating, spin coating, and dispenser may be employed as the coating method. Inkjet is a method of spraying and applying a coating liquid material as droplets on a plate-like member, similar to spray coating, and the same effect as spray coating can be expected. Including spray coating and inkjet, it is called a droplet spray coating method.

  A coating method using a blade, squeegee, or centrifugal force generally includes a step of removing excess coating liquid material from the plate-like member. It is more suitable for applications using a coating liquid material having a relatively high viscosity than applications for coating a coating liquid material having a relatively low viscosity on a plate-like member.

  On the other hand, a method of applying so that the coating liquid material gradually accumulates on the plate member, such as a droplet spray coating method, can apply a large amount of the coating liquid material relatively easily. The method using the dispenser can also obtain an effect similar to the droplet spray coating method by taking a method such as supplying the coating liquid material from the dispenser to the plate-like member at multiple points.

  The plate-like member produced in this example and having a coating film on the entire surface is coated with a water-repellent film on the side surface, and the film thickness uniformity on the surface is good. It has a feature that swell is remarkably suppressed (typically, there is no swell).

  According to the embodiment described above, a coating film having negative optical anisotropy in the thickness direction is formed on the surface of the plate member, and this plate member can be used as one substrate of the vertical alignment type liquid crystal display device. .

  FIG. 4 is a cross-sectional view of a liquid crystal display device manufactured according to the embodiment.

  The transparent electrodes 5 and 15 patterned on the surfaces of the pair of plate-like members 1 and 11 are formed of, for example, ITO (Indium Tin Oxide) or the like, and cover the transparent electrodes 5 and 15 on a predetermined region of the plate-like members 1 and 11. Vertical alignment films 6 and 16 are formed. The plate-like members 1 and 11 (vertical alignment films 6 and 16) are arranged to face each other with the sealing material 21 interposed therebetween to form empty cells. Liquid crystal 7 is injected into the empty cell. A liquid crystal layer 7 is sandwiched between both plate-like members 1 and 11. The water repellent material film 3 is applied to the side surface of one plate-like member 1, and the optical compensation film 2 is applied to the entire outer surface of the plate-like member 1. The production of the water repellent material film 3 and the optical compensation film 2 is the same as that of the water repellent material film and the coating film in the above-described embodiment. Crossed Nicols polarizing plates P1 and P2 are disposed on both sides of the liquid crystal cell thus formed. The liquid crystal molecules 8 in the liquid crystal layer 7 are aligned substantially perpendicular to the substrate surface when no display voltage is applied due to the influence of the vertical alignment films 6 and 16. Such a liquid crystal layer has positive uniaxial optical anisotropy in the thickness direction. The optical compensation film 2 is a so-called −c plate having negative uniaxial optical anisotropy in the thickness direction. The optical anisotropy of the optical compensation film 2 compensates for the optical anisotropy of the liquid crystal layer 7.

  Instead of forming an optical compensation film only on one side of the liquid crystal cell, an optical compensation film can be formed on both sides of the liquid crystal cell. Although the case where the optical compensation film is applied after creating the liquid crystal cell has been described, the optical compensation film may be applied and then assembled into the liquid crystal cell. Although the optical compensation film is formed on the outer surface of the counter substrate of the liquid crystal display device, the optical compensation film may be formed on the inner surface of the counter substrate. By arranging the liquid crystal layer and the optical compensation film close to each other, a better optical compensation effect can be expected.

  The plate member of the liquid crystal cell may be formed of a glass substrate such as blue plate glass or non-alkali glass, a polycarbonate sheet, or the like. It is also possible to use a substrate having a hydrophilic surface on the surface of the substrate having water repellency.

  As mentioned above, although this invention was demonstrated along the Example, this invention is not limited to these. It will be apparent to those skilled in the art that various modifications, substitutions, improvements, combinations, and the like can be made.

1 plate-like member,
2 coating film,
3 Water repellent film 11 Spray nozzle.

Claims (7)

A plate-like member that is hydrophilic and has a surface and a side surface surrounding the surface ;
Surrounding the plate member surface, a water-repellent film applied to the entire circumference of the plate member side surface ;
A coating film applied to the entire surface of the plate member;
Have a, wherein the coating film and the water-repellent film in contact only at the boundary between the side surface and the surface, the plate-like member having a coating film.   The plate-like member having a coating film according to claim 1, wherein the water-repellent film and the coating film are in linear contact. A first plate member comprising the plate member according to claim 1 or 2, and
A second plate-like member disposed opposite to the first plate-like member;
Electrodes disposed on opposing surfaces of the first plate member and the second plate member;
A liquid crystal layer sandwiched between the first and second plate-like members;
A liquid crystal display device.   The liquid crystal display device according to claim 3, wherein the liquid crystal layer is a vertically aligned liquid crystal layer, and the coating film is a film having optical anisotropy. A step of applying a water-repellent film to the entire circumference of the side surface of the plate-like member that is hydrophilic and has a surface and a side surface surrounding the surface ;
Applying a hydrophilic coating solution to the entire surface of the plate-like member to form a coating film;
Unrealized, wherein the coating film and the water-repellent film in contact only at the boundary between the side surface and the surface, a manufacturing method of the plate-like member having a coating film. A pair of plate-like member surfaces that are hydrophilic and have a surface and side surfaces, a patterned transparent electrode, and a vertical alignment film that covers a predetermined range of the plate-like member are sequentially formed, and the vertical alignment film is opposed to each other. A step of sandwiching the liquid crystal layer to create a liquid crystal cell;
Applying a water-repellent film to the entire side surface surrounding the outer surface of one of the plate-like members;
A step of applying a hydrophilic coating liquid on the entire outer surface of a plate-like member having a water-repellent film coated on the side surface by a droplet spray coating method to form a coated film, the coating film and the water-repellent film Is in contact with only the boundary between the outer surface and the side surface, and
A method for manufacturing a liquid crystal display device comprising:   The method for manufacturing a liquid crystal display device according to claim 6, wherein the liquid crystal cell is a vertical alignment type liquid crystal cell, and the coating film is an optical compensation film having negative optical anisotropy in a thickness direction.

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