JP4023092B2 - Manufacturing method of liquid crystal display device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal display device and a manufacturing method thereof. More specifically, a plurality of pixels arranged in a matrix pattern by landing the first ink by an inkjet method on a substrate, a light shielding layer arranged in a gap between the pixels, and a plurality of pixels on the light shielding layer The present invention relates to a liquid crystal display device comprising: a plurality of protrusions having a predetermined height, wherein a plurality of protrusions having a light-shielding layer landed with a second ink having ink repellency by an inkjet method .
[0002]
[Prior art]
In recent years, with the development of personal computers, in particular with the development of portable personal computers, the demand for liquid crystal display devices has increased rapidly. This liquid crystal display device is widely used in notebook computers, desktop computers, in-vehicle navigation systems, electronic still cameras, game machines, projectors, mobile phones and the like.
[0003]
In such a liquid crystal display device, a cell is usually formed by adhering a color filter substrate on which a common electrode is provided and a pixel electrode substrate on which a pixel electrode is provided via a sealing material. It is manufactured by encapsulating liquid crystal, and colors are given to each pixel of the device. In this case, in order to maintain the accuracy of the cell interval, a powdery spacer is usually provided in the cell.
[0004]
With respect to such a color liquid crystal display device, as the demand for high-definition image display increases year by year, the demand for highly accurate and highly efficient pixel formation has increased. In order to meet such a demand, a method performed by an inkjet printing technique has been adopted. In this technique, ink is stored in a pressure chamber of an ink jet head using piezoelectric thin film elements, and pixel forming ink is ejected by volume change of the pressure chamber due to vibration of the piezoelectric elements. However, it is difficult to perform complicated processes such as exposure, development, and cleaning using masks with different patterns for each pixel, as in the conventional pixel formation technique using photolithography. Since it is not necessary, it is possible to improve the production efficiency and to control the amount of ink at a high level, which is an excellent method in terms of enabling efficient formation of high-definition pixels. .
[0005]
On the other hand, the demand for the above-described display of high-definition images is not limited to only the pixels, but also for the formation of spacers that can contribute to the display of high-definition images by maintaining the accuracy of the cell spacing. High accuracy and high efficiency are demanded.
[0006]
As a method for arranging such spacers, conventionally, a method in which powdery spacer particles are randomly distributed in cells has been used. However, light-impermeable spacer particles are also arranged on pixels. Therefore, there is a problem that display quality such as contrast is deteriorated.
[0007]
In addition, a method has been proposed in which a resin pillar is formed by a photolithographic technique on a light shielding layer formed in a gap between pixels to form a spacer. In this method, a mask having a pattern different from that for pixel formation is used. In addition, since complicated steps such as exposure, development, and washing are required, there is a problem that production efficiency is lowered.
[0008]
Further, in view of these problems, an inkjet apparatus is used to eject a plurality of spacers on a substrate by one ejection, and the plurality of spacers are aggregated and arranged at substantially constant intervals. A spacer discharge method is disclosed (Japanese Patent Laid-Open No. 11-24083).
[0009]
[Problems to be solved by the invention]
However, this method is an excellent method in terms of reducing the number of spacers arranged in the pixel region, but due to the technical limitation of the ink jet system that a liquid material needs to be used as a discharge material, it is predetermined. It is necessary to prepare a discharge liquid in which spacer particles are dispersed in a liquid, and it takes time and effort, and it is difficult to control the number of the plurality of spacer particles contained in the landing droplets to be constant. It was not always satisfactory.
[0010]
The present invention has been made in view of the above-described problems, and an object thereof is to provide a liquid crystal display device having a highly accurate spacer and a highly efficient manufacturing method thereof.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a liquid crystal display device according to the present invention includes a plurality of pixels arranged in a matrix pattern by landing a first ink on a substrate by an inkjet method, and gaps between the plurality of pixels. A second ink having a composition different from that of the first ink by an ink jet method at a plurality of locations on the light shielding layer disposed and the light shielding layer, wherein the light shielding layer exhibits ink repellency and has a viscosity. And a plurality of protrusions having a predetermined height and disposed by landing a second ink of 10 to 100 mPa · s.
A plurality of pixels arranged in a matrix pattern by landing the first ink by an inkjet method on the substrate; a light shielding layer disposed in a gap between the pixels; and a plurality of pixels on the light shielding layer. A second ink having a composition different from that of the first ink is applied to the portion by the ink jet method, wherein the light shielding layer exhibits ink repellency and has a solid content concentration of 30% or more. And a plurality of protrusions having a predetermined height, which are arranged in such a manner.
[0012]
With such a configuration, since the plurality of protrusions function as high-accuracy spacers, it is possible to provide a liquid crystal display device including high-precision spacers.
[0013]
In the method of manufacturing a liquid crystal display device according to the present invention, the light shielding layer is arranged in a lattice shape on the substrate, and the first ink is landed on the lattice-shaped gap of the light shielding layer by the inkjet method to form a matrix pattern. A plurality of pixels are arranged in a shape, and a second ink having a composition different from that of the first ink is formed at a plurality of locations on the light shielding layer by an inkjet method, and the light shielding layer exhibits ink repellency. In addition, a plurality of protrusions having a predetermined height are disposed by landing a second ink having a viscosity of 10 to 100 mPa · s.
Further, on the substrate, the light shielding layer is arranged in a lattice shape, and a plurality of pixels are arranged in a matrix pattern shape by landing the first ink by an ink jet method in the lattice shape gap of the light shielding layer, A second ink having a composition different from that of the first ink by an inkjet method at a plurality of locations on the light shielding layer, wherein the light shielding layer exhibits ink repellency and has a solid content concentration of 30% or more. A plurality of protrusions having a predetermined height are disposed by landing the second ink.
[0014]
With such a configuration, it is possible to provide a highly efficient manufacturing method for a liquid crystal display device including a highly accurate spacer.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be specifically described with reference to the drawings.
[0016]
As shown in FIG. 1, the liquid crystal display device of the present invention includes a plurality of pixels 2 arranged in a matrix pattern by landing a first ink on a substrate 1 by an inkjet method, and a plurality of pixels 2. A plurality of light shielding layers 3 arranged in the gap and a plurality of predetermined heights arranged by landing the second ink showing ink repellency on the light shielding layer 3 at a plurality of locations on the light shielding layer 3 by an ink jet method. And a protruding portion 4.
[0017]
The substrate 1 used in the liquid crystal display device of the present invention is not particularly limited as long as it has excellent mechanical strength. For example, a transparent glass substrate, a light-transmitting substrate such as a plastic substrate (film) such as acrylic, etc. And surface treated products thereof. Depending on the embodiment, it may be light-impermeable.
[0018]
The pixel 2 can have various sizes and pitches in accordance with the resolution of the target liquid crystal display device. In this embodiment, the pitch in the X direction is 114 μm and the pitch in the Y direction is 75 μm. The volume of one pixel 2 is preferably 1 to 50 pl (picoliter), and more preferably 5 to 20 pl. If it is less than 1 pl, a sufficient coloring effect may not be obtained, and if it exceeds 50 pl, a high-definition pixel may not be formed. Note that R, G, and B attached to the pixel 2 in FIGS. 1A and 1B indicate that the color of each pixel is red, green, and blue (the same applies to the case of FIG. 4). Is).
[0019]
In the present invention, the first ink used for forming the pixel 2 may be water-based or solvent-based. For example, after dispersing an inorganic pigment in a polyurethane resin oligomer, cyclohexanone and butyl acetate are added as a low boiling point solvent, butyl carbitol acetate is added as a high boiling point solvent, and 0.01% of a nonionic surfactant is added. Examples thereof include those added as a dispersant and having a viscosity of 6 to 8 mPa · s.
Further, as will be described later, the same material as the second ink may be used.
[0020]
The light shielding layer 3 (for example, a black matrix or a black mask) disposed in the gap between the pixels 2 is made of a material that has light shielding properties and ink repellency with respect to a second ink described later. Specifically, a fluorine-based resin can be mentioned, and its water contact angle of 40 ° or more is preferable because it enables highly accurate formation of the protrusions 4 described later, and is 50 ° or more. Some are more preferred.
The light shielding layer 3 can usually be formed using a photolithography technique.
The width of the light shielding layer 3 is preferably 20 to 50 μm. If the thickness is less than 20 μm, the formation of the protrusions 4 may be difficult, and if the thickness exceeds 50 μm, the interval between the pixels 2 becomes too wide to be applied to a high-definition liquid crystal display device. There is. A bank material made of resin or the like may be laminated on the light shielding layer 3 to facilitate the formation of the pixels.
[0021]
Examples of the configuration of the inkjet head in the inkjet system used in the present invention include those shown in FIG. The ink jet head 20 is of a type in which an ink supply channel is formed in a pressure chamber substrate. As shown in FIG. 2, the inkjet head 20 mainly includes a pressurizing chamber substrate 21, a nozzle plate 22, and a base 23.
[0022]
The pressurizing chamber substrate 21 is formed on a silicon single crystal substrate and then separated into each. The pressurizing chamber substrate 21 includes a plurality of strip-shaped pressurizing chambers 24 and includes a common flow path 25 for supplying ink to all the pressurizing chambers 24. The pressurizing chambers 24 are separated by side walls 26. The pressurizing chambers 24 are arranged in two rows, and 128 are formed per row, thereby realizing an ink jet head having a print density of 256 (pieces) nozzles. A diaphragm film and a piezoelectric thin film element are formed on the substrate 23 side of the pressurizing chamber substrate 21. Further, the wiring from each piezoelectric thin film element is converged on the wiring board 27 which is a flexible cable, and is connected to an external circuit (not shown) of the base 23. The external circuit is instructed to discharge ink for coloring the color filter, and discharges ink.
[0023]
The nozzle plate 22 is joined to the pressurizing chamber substrate 21. A nozzle 28 for extracting ink droplets is formed at a position corresponding to the pressurizing chamber 24 in the nozzle plate 22. The nozzle 28 can have a diameter of 28 μm, for example. In this case, the amount of ink droplets ejected at one time is about 10 pl to 20 pl. The nozzles 28 are formed in two rows at a predetermined arrangement pitch. For example, the row interval and the arrangement pitch can be 141 μm and 75 μm, respectively.
[0024]
The base 23 is a rigid body such as plastic or metal and serves as a mounting base for the pressurizing chamber substrate 21.
[0025]
FIG. 3 is an explanatory diagram schematically showing an electrical connection relationship with respect to the main part of the inkjet head 20. One electrode of the drive voltage source 31 is connected to the lower electrode 33 of the inkjet head via the wiring 32. The other electrode of the drive voltage source 31 is connected to an upper electrode 37 corresponding to each pressurizing chamber 24a to 24c via a wiring 34 and switches 36a to 36c.
[0026]
In FIG. 3, only the switch 36b of the pressurizing chamber 24b is closed, and the other switches 36a and 36c are opened. The pressurizing chambers 24a and 24c in which the switches 36a and 36c are opened indicate a standby state for ink ejection. At the time of ink ejection, for example, the switch is closed like the switch 24b, and a voltage is applied to the piezoelectric film. This voltage is applied in the same polarity as the polarization direction of the piezoelectric film 39 indicated by the arrow A, in other words, the same voltage as the polarity of the applied voltage during polarization. The piezoelectric film 39 expands in the thickness direction and contracts in the direction perpendicular to the thickness direction. Due to this contraction, stress acts on the interface between the piezoelectric film 39 and the diaphragm 40, and the piezoelectric film 39 and the diaphragm 40 bend downward. Due to this deflection, the volume of the pressurizing chamber 24 b decreases, and the ink droplets 42 are ejected from the nozzles 41. Pixels are colored by the ink droplets 42. Thereafter, when the switch 36b is opened again, the piezoelectric film 39 and the vibration plate 40 that have been bent are restored, and the volume of the pressurizing chamber 24b expands to fill the pressurizing chamber 24b with ink from an ink supply path (not shown). Is done. The vibration frequency of the piezoelectric film 39 is set to 7.2 kHz.
[0027]
As shown in FIG. 1, a plurality of protrusions 4 having a predetermined height are arranged at a plurality of locations on the light shielding layer 3 by landing the second ink by an ink jet method. As described above, when a bank material made of resin or the like is laminated on the light shielding layer 3, the protrusions 4 are disposed at a plurality of locations on the light shielding layer 3 and the bank material (not shown). Will be.
[0028]
Here, as the ink jet system used for forming the protrusions 4, it is preferable to use the same ink jet head as that used for forming the pixels because no additional equipment is required, which improves production efficiency. .
[0029]
The second ink used in the present invention is not particularly limited as long as the light shielding layer 3 is a combination that has ink repellency with respect to the second ink, but for example, a thermosetting resin Or what contains a photocurable resin is preferable from improving production efficiency, since it can harden | cure in a short time.
[0030]
The viscosity is preferably 10 to 100 mPa · s. When the pressure is less than 10 mPa · s, it may be difficult to form the protrusion, and when it exceeds 100 mPa · s, it may be difficult to eject from the inkjet head.
[0031]
Specific examples of the second ink include a urethane resin, an acrylic resin, a novolac resin, a cardo resin, a polyimide resin, an epoxy resin dilution, and the like.
[0032]
Further, it is preferable that the material constituting the second ink is the same as the material constituting the first ink in order to improve production efficiency. In this case, the first ink is composed of R (red), G (green) and B (blue) inks, and the second ink is R (red), G (green) and B ( It is preferable that the ink is composed of a mixture of three inks (blue) because it is easy to implement by specifying an operation program of an ink jet method, and it is preferable to improve production efficiency. Also, the discharge amount of the second ink This makes it easy to determine the discharge amount and enables precise control of the discharge amount, and the accuracy of the height H of the plurality of protrusions 4 from the light shielding layer 3 can be increased. Specifically, the accuracy of the height H controlled by the ink ejection amount is preferably within 2% in order to obtain a high-definition apparatus that maintains the cell spacing precisely.
[0033]
As shown in FIG. 4, in another embodiment of the liquid crystal display device of the present invention, a plurality of protrusions 4 are formed in a plurality of holes 5 formed at a plurality of locations on the light shielding layer 3 by an inkjet method. The second ink is disposed by landing.
[0034]
Regarding the dimensions of the protrusions 4, the height H from the light shielding layer 3 depends on the interval between the liquid crystal cells used in the apparatus, but is 10 to 20 μm immediately after the second ink is ejected, and after the curing. 2-10 micrometers is preferable. If the height H after curing is less than 2 μm, a sufficient spacer effect may not be obtained, and if it exceeds 10 μm, it may not be applicable to an apparatus having a narrow interval between liquid crystal cells.
The dimensional relationship described above is similarly applied to the case of the embodiment described above.
[0035]
As for the diameter D of the circle which is a cross section of the projection part 4, 10-30 micrometers is preferable. If it is less than 10 μm, a sufficient spacer effect may not be obtained. If it exceeds 30 μm, it may not be applicable to a high-definition device.
[0036]
As a method for forming the hole portion 5, for example, a mask having a predetermined shape can be used when the light shielding layer 3 is formed using a photolithography technique.
[0037]
As shown in FIG. 5, the above-described configuration (a plurality of pixels 2 arranged in a matrix pattern shape by landing the first ink on the substrate 1 by an ink jet method, and arranged in the gaps between the plurality of pixels 2. A plurality of protrusions 4 having a predetermined height, disposed on the light shielding layer 3 and a plurality of locations on the light shielding layer 3 by landing the second ink on the light shielding layer 3 that exhibits ink repellency by an inkjet method. The liquid crystal display device 100 of the present invention including the protective layer 101, the common electrode 102, the pixel electrode substrate 103, and the pixel electrode substrate 103 facing the common electrode 102 is provided. The pixel electrode 104 and a liquid crystal layer 105 sandwiched and sealed between two opposing electrodes 102 and 104 are provided.
[0038]
The liquid crystal display device 100 of the present invention preferably includes alignment films 106 and 107 between the common electrode 102 and the liquid crystal layer 105 and / or between the liquid crystal layer 105 and the pixel electrode substrate 103. .
[0039]
Further, it is preferable that the polarizing plate 108 or 109 is provided on the outer surface of the substrate 1 and / or on the outer surface of the pixel electrode substrate 103. The backlight L is irradiated from the polarizing plate 109 side.
[0040]
In addition, there is no restriction | limiting in particular as a material used for said structure, Each can be used widely each.
[0041]
【Example】
A hole was formed in the ink repellent bank portion of the color filter manufactured by the ink jet method with a laser, and an ink reservoir was formed at the landing position of the ink forming the protrusion 4 shown in FIG. Thereafter, the color filter ink was ejected into the ink reservoir by an ink jet drawing apparatus, and it was confirmed that the ink swelled in a convex shape as shown in FIG. Ink 4 was prepared by increasing the solid content concentration to 30% or more and reducing the viscosity at high temperature. The height of the ink immediately after ejection was about 15 μm, and then it was cured by a hot air drying furnace, leaving a convex portion having a height of 3 μm. The protrusions could be produced with good reproducibility at a plurality of locations. When the counter glass and the sealing material were bonded together, it was confirmed that an empty cell having a cell thickness of 3.5 to 4 μm was completed and functioned as a spacer.
[0042]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a liquid crystal display device including a highly accurate spacer and a highly efficient manufacturing method thereof.
[Brief description of the drawings]
FIG. 1 schematically shows an embodiment of a liquid crystal display device of the present invention, where (a) is a plan view, (b) is a partially enlarged view, and (c) is a cross-sectional view taken along line AA. It is.
FIG. 2 is an exploded perspective view schematically showing an ink jet head used in the present invention.
FIG. 3 is an explanatory view schematically showing electrical connection of an ink jet head used in the present invention.
4A and 4B schematically show another embodiment of the liquid crystal display device of the present invention, in which FIG. 4A is a plan view and FIG. 4B is a cross-sectional view taken along the line BB in FIG.
FIG. 5 is a cross-sectional view schematically showing the entire liquid crystal display device including the embodiment shown in FIG.
[Explanation of symbols]
1: Substrate 2: Pixel 3: Light-shielding layer 4: Projection 5: Hole 20: Inkjet head 21: Pressurization chamber substrate 22: Nozzle plate 23: Base 24: Pressurization chamber 25: Common channel 26: Side wall 27: Wiring board 28: Nozzle 31: Driving voltage source 32: Wiring 33: Lower electrode 34: Wiring 36a: Switch 36b: Switch 36c: Switch 37: Upper electrode 39: Piezoelectric film 40: Diaphragm 41: Nozzle 42: Ink droplet 100 : Liquid crystal display device 101: protective layer 102: common electrode 103: pixel electrode substrate 104: pixel electrode 105: liquid crystal layer 106: alignment film 107: alignment film 108: polarizing plate 109: polarizing plate

Claims (6)

On the substrate, a light shielding layer is arranged in a lattice shape,
A plurality of pixels are arranged in a matrix pattern by landing the first ink by an inkjet method in the lattice-shaped gap of the light shielding layer,
A second ink having a composition different from that of the first ink is applied to a plurality of locations on the light shielding layer by an ink jet method, and the light shielding layer exhibits ink repellency and has a viscosity of 10 to 100 mPa · s. A method of manufacturing a liquid crystal display device, wherein a plurality of protrusions having a predetermined height are disposed by landing a second ink. On the substrate, a light shielding layer is arranged in a lattice shape,
A plurality of pixels are arranged in a matrix pattern by landing the first ink by an inkjet method in the lattice-shaped gap of the light shielding layer,
A second ink having a composition different from that of the first ink by an ink jet method at a plurality of locations on the light shielding layer, wherein the light shielding layer exhibits ink repellency and has a solid content concentration of 30% or more. A method of manufacturing a liquid crystal display device, wherein a plurality of protrusions having a predetermined height are disposed by landing a second ink. Forming a plurality of holes at a plurality of positions on the light-shielding layer, the hole, by an inkjet method, according to claim 1 or 2, disposing the plurality of protrusions by landing the second ink Liquid crystal display device manufacturing method. The manufacturing method of the liquid crystal display device in any one of Claims 1-3 using the fluorine-type resin whose contact angle with respect to the water is 40 degrees or more as the said light shielding layer. The manufacturing method of the liquid crystal display device in any one of Claims 1-4 using what contains a thermosetting resin or a photocurable resin as said 2nd ink. The method for manufacturing a liquid crystal display device according to claim 1 , wherein the predetermined heights of the plurality of protrusions are determined by controlling an ejection amount of the second ink by an inkjet method.

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