Liquid crystal cells – elements and systems – Nominal manufacturing methods or post manufacturing...
Reexamination Certificate
2001-05-21
2003-12-23
Ton, Toan (Department: 2871)
Liquid crystal cells, elements and systems
Nominal manufacturing methods or post manufacturing...
C349S189000, C349S106000, C347S043000
Reexamination Certificate
active
06667795
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a head unit used for discharging a liquid (ink or EL (electroluminescence) display material) toward a substrate from a liquid head so as to manufacture display device panels containing color filters, EL display devices, etc., an apparatus for manufacturing panels for display devices containing color filters, EL display devices, etc., using the head unit, the manufacturing method thereof, manufacturing method for liquid crystal display devices having color filters, and devices having the liquid crystal display devices.
2. Description of the Related Art
Liquid discharging heads (ink jet heads) can be freely controlled as to the position and amount of liquid (ink) discharged, and accordingly are not only used for common printing purposes, but are further applied to various industries, primarily color filter manufacturing. The following is a description of color filter manufacturing with the ink jet method, which is a representative usage of the present invention.
Advancements in personal computers, particularly in portable personal computers, have led to an increase in liquid crystal displays, particularly in color liquid crystal displays. However, the cost of liquid crystal displays needs to be reduced for even further widespread use, and there is increasing demand for reduction in the cost of color liquid crystal displays, which tend to be more expensive than other display devices because of their quality. Heretofore, various attempts have been made to satisfy the above demands for reductions in cost while satisfying the required properties of the color filter, but no method has yet been established which satisfies all demands. The following is a description of several color filter manufacturing methods.
A first color filter manufacturing method is the dyeing method. The dyeing method involves coating a glass substrate with a water-soluble polymer material, which is the dyeing material, and the water-soluble polymer material is patterned into a desired form by photolithography, following which the obtained pattern is dipped in a dye bath so as to obtain a colored pattern. This process is performed three times, thereby obtaining a color filter layer of R (red), G (green), and B (blue) on the glass substrate.
A second color filter manufacturing method is the pigment dispersion method, which has come to be used most widely in recent years. The pigment dispersion method involves forming a photosensitive resin layer wherein pigment is dispersed on a glass substrate, and patterning this layer, thereby obtaining a monochromatic pattern. This is repeated once for each color, for a total of three times, thereby forming an RGB color filter layer.
A third color filter manufacturing method is the electrocoating method. The electrocoating method involves patterning transparent electrodes on a glass substrate, following which the glass substrate is dipped in an electrocoating paint fluid containing pigment, resin, electrocoating fluid, etc., so as to perform electrocoating of a desired color. This process is repeated for each color so as to apply the colors of R, G, and B on the substrate, following which the resin is thermally hardened, thus forming a colored layer on the substrate.
A fourth color filter manufacturing method is the printing method. The printing method involves printing with a pigment dispersed in a thermally hardening resin three times so as to color the colors for R, G, and B, following which the resin is thermally hardened, thus forming a colored layer on the substrate.
Each of the above methods usually is followed by forming a protective layer on the surface of the colored layer.
All four of these methods share one point: that the same process must be performed three times in order to color the three colors R, G, and B, which means that the great number of processes decreases yield, increases costs, and so forth, which are shortcomings that have been pointed out. Further, with the electrocoating method, the form of patterns which can be formed are limited, so application to TFT-type color liquid crystal displays is difficult. Also, the printing method has poor resolution and smoothness, and thus has shortcomings in that producing finer patterns is difficult, and so forth.
In order to supplement these shortcomings, Japanese Patent Application Laid-Open No. 59-75205, Japanese Patent Application Laid-Open No. 63-235901, Japanese Patent Application Laid-Open No. 63-294503, and Japanese Patent Application Laid-Open No. 1-217302 disclose methods for forming a color filter using the ink jet method. These methods involve ejecting inks containing coloring matter of the three colors R (red), G (green), and B (blue), on a photo-transmitting substrate by the ink jet method, and drying the inks so as to form filter elements. With an ink jet method such as this, the filter elements for R, G, and B can be formed all at once, leading to marked simplification of the manufacturing process, and great reductions in costs.
Now, when forming color filters with the ink jet method, there is the need to position the head having multiple ink discharge orifices and the substrate in a highly precise manner. However, the above publications do not take into consideration the production aspects of mass-producing such color filters, and accordingly the color filters cannot be manufactured in a stable manner. That is to say, the above publications are insufficient with regard to mass-production of the color filters.
In order to improve such insufficiencies, Japanese Patent Application Laid-Open No. 9-49919 discloses positioning heads having multiple ink discharging orifices and the substrate in a highly precise manner, thereby improving the production of color filters. According to this publication, of the three RGB heads, one color head is used as a reference and the other two color heads are positioned relative to that head beforehand, and are fixed at the time of printing, so that positioning of heads having multiple ink discharging orifices and the substrate can be performed in a highly precise manner, thus improving production of color filters.
Now, recent advancements in liquid crystal device manufacturing technology have led to increased size of glass substrates and image size (i.e., color filter size), and finer pixels. Conventionally, the size of glass substrates has been around 360 mm×465 mm, but recently this has increased to around 550 mm×650 mm, 680 mm×880 mm, and 730 mm×920 mm. The screen size has also been increasing yearly in a corresponding manner, such as 10.4 inch, 12.1 inch, 13.3 inch, 14.1 inch, 15.0 inch, 17.0 inch, 18.0 inch, and 20.0 inch screens. Further, the number of pixels of the color filters has been increasing in the manner of VGA (640 ×480), SVGA (800×600), XGA (1024×768), SXGA (1280×1024), SXGA+ (1400×1050), UXGA (1600×1200), and QXGA (2048×1536). Thus, color filters are increasing in resolution and fineness.
In the event of using such large-size substrates and manufacturing color filters for large-size screens with fine displays, the amount of time necessary for manufacturing each color filter is longer than that for conventional color filters with smaller screen sizes and lower resolution. An arrangement for realizing reduction in manufacturing time and further improving productivity can be conceived wherein a great number of heads for discharging ink of the same color are used. However, Japanese Patent Application Laid-Open No. 9-49919 only mentions using one head per color per head unit, and does not make description of what sort of head configuration would be used in the event that multiple heads of for the same color were to be used on one head unit.
In the event of manufacturing a color filter using multiple heads of the same color, the present inventor has found that simply using multiple heads would lead to increased time necessary for head positioning, which would counter the object of reduction in manufa
Canon Kabushiki Kaisha
Fitzpatrick ,Cella, Harper & Scinto
Qi Mike
Ton Toan
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