Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
2000-07-11
2003-10-14
Ton, Toan (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S106000, C349S138000
Reexamination Certificate
active
06633353
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a color filter substrate having a colored layer formed on a metal and to a manufacturing process therefor. More particularly, the present invention relates to a liquid crystal device using the above substrate and to a manufacturing process therefor, and relates to an electronic apparatus using the above device.
BACKGROUND ART
As is well known, liquid crystal devices do not themselves emit light; instead, they produce displays or the like simply by changing the paths of light. Therefore, all liquid crystal devices necessarily have some type of arrangement for directing light into panels. In view of this, liquid crystal devices are far different from other display devices, such as electroluminescent displays and plasma displays. A liquid crystal device in which light incident from a light source or the like disposed at a rear side of a panel is emitted to an observing side after passing through the panel is called a transmissive type, and a liquid crystal device in which ambient light incident from an observing side is emitted to an observing side by reflection by a panel, is called a reflective type.
In reflective type devices, the amount of ambient light incident from the observing side is not large compared to light incident from a light source disposed at a rear side of a panel. In addition, reflective type devices have high attenuation of light in each part thereof because, when the light is reflected, the light retraces its path through the panel, so that light emitted to an observing side is less than that in transmissive types. Accordingly, reflective type devices have a problem that display screens thereof are generally darker compared to transmissive type devices.
On the other hand, reflective type devices have advantages such as being able to produce a display not having a light source, which consumes large amount of electric power, being highly visible outdoors even in bright light, and the like. Hence, in some cases, the above advantages of reflective type devices overcome problems therein. Consequently, there is an increasing demand for reflective type liquid crystal devices for portable electronic apparatuses; however, a substantial problem remains in that when there is practically no ambient light, users cannot see the display of reflective type devices. A so-called “transflective liquid crystal device” is proposed as one solution to overcome this problem. In a bright environment, the liquid crystal device mainly uses reflection of ambient light, similar to that used in ordinary reflective type devices. However, in a dark environment, the transmissive type device is additionally used by lightning a light source disposed on a rear side of a panel, and therefore the device display can be seen in either situation. Moreover, concomitant with a recent demand for color displays for portable electronic devices, office automation apparatuses, and the like, color displays in transflective type liquid crystal devices are required in many cases.
A transflective liquid crystal device capable of providing a color display is described in, for example, Japan Unexamined Patent Application Publication No. 7-318919. The liquid crystal device which is disclosed in the above unexamined patent application, is provided inside a liquid crystal layer with pixel electrodes which also serve as a transflective film and has an arrangement for producing a color display. In the above arrangement, a color display is produced by coloring light by birefringent effects of a liquid crystal layer and a retardation film, and by polarization effects of polarizers provided at an observing side and at a rear side of a liquid crystal panel. Since the transflective film is provided inside the liquid crystal layer in the arrangement described above, double images, blurred display, and the like caused by parallax are avoided, and superior bright colored light can be obtained compared to an arrangement having a transflective film outside a liquid crystal layer.
DISCLOSURE OF THE INVENTION
However, the liquid crystal device described above has a problem of poor color reproducibility because light coloration is produced by birefringent effects and polarization effects.
The present invention was made taking the problem described above into consideration. A first object of the present invention is to provide a transflective or a reflective liquid crystal device with improved color reproducibility. As described in the above unexamined patent application, a transflective film is generally composed of aluminum or an aluminum alloy having aluminum as a primary component. When a colored layer, such as a color filter, a shading layer, or the like, is directly formed on the transflective film, aluminum is deteriorated during a forming process, and reflection characteristics may be seriously affected. When the colored layer is formed by an etching method, for example, a surface of the aluminum may be damaged by an etching solution. In addition, in some cases when the colored layer is formed by a color resist method, a surface of the aluminum may be damaged when the color resist is developed.
Accordingly, a second object of the present invention is to provide a color filter substrate, a liquid crystal device, and a manufacturing method therefor, in which, during a forming process for the colored layer, damage or deterioration of the aluminum, which is used as a metallic film for the transflective film and the reflective electrode, is prevented by a simple process.
To achieve the first object described above, the color filter substrate of the present invention, which is to be applied to the liquid crystal device, is a color filter substrate having a metallic film provided between the substrate and a colored layer, in which the metallic film and the colored layer are separated by a protective film provided between the metallic film and the colored layer.
According to the present invention, since the metallic film and the colored layer are separated by the protective film, the surface of the metallic film is not deteriorated when the colored layer is formed. Hence, a color filter substrate having good reflection characteristics at the metallic film is obtained.
An oxide film of the metallic film may be used as the protective film. In this case, an oxide film of the metallic film is preferably an anodized film. The reasons for this are that an anodizing method can easily control the thickness of the oxide film and form a dense oxide film having fewer defects such as pinholes. In addition, the colored layer may be formed by an electrodeposition method with proper thickness control.
As other examples of the protective films, oxides other than the metal oxide described above, organic dielectric films, and nitrides may be used. Oxides other than the metal oxide includes silicon oxides such as SiO
2
, the organic dielectric films include acrylic resins, and the nitrides include silicon nitrides, typically Si
3
N
4
. When an oxide other than the oxides of the metallic films is used as a protective film, reflectance deterioration can be suppressed because of a low refractive index. When an organic dielectric film is employed, a protective film can be easily formed by a method such as a spin coat method or a roll coat method. When a nitride is used as a protective film, an advantage is to suppress reflectance deterioration because of low refractive index.
The protective film may be formed by optionally combining two or more films among the above oxide films of the metal, an oxide films other than the above, the organic dielectric films, and the nitride films.
A metallic film including a primary component, such as aluminum, silver, chromium or the like, is used as the metallic film. When a metallic film including aluminum as a primary component is used, a metallic film having a high reflectance is obtained by using an inexpensive material. In addition, since an oxide film can be obtained from aluminum by anodization, a protective film composed of the oxide film can be easily formed.
Okamoto Eiji
Seki Takumi
Takizawa Keiji
Harness & Dickey & Pierce P.L.C.
Seiko Epson Corporation
Ton Toan
LandOfFree
Color filter substrate and manufacturing process therefor,... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Color filter substrate and manufacturing process therefor,..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Color filter substrate and manufacturing process therefor,... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3125395