Liquid crystal cells – elements and systems – Particular structure – Having significant detail of cell structure only
Reexamination Certificate
1999-11-12
2002-06-04
Ton, Toan (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Having significant detail of cell structure only
C349S084000, C349S141000, C349S092000, C349S093000
Reexamination Certificate
active
06400430
ABSTRACT:
BACKGROUND OF THE INVENTION
(1) Field of the Invention
The present invention relates to a liquid crystal light control element that can be incorporated into personal digital assistants, notebook or laptop computers, and the like. The invention also relates to an optical device such as a liquid crystal display device, and an electric device such as a memory device, an electroluminescent device, an electrophoretic device and the like. The invention further relates to a method of producing such devices.
(2) Description of the Prior Art
Various liquid crystal display modes have been suggested as a display mode of a liquid crystal display device. For example, a twisted nematic (TN) liquid crystal, a super twisted nematic (STN) liquid crystal, a polymer dispersed liquid crystal, an in-plane switching (IPS) type liquid crystal device, and the like have been suggested. In all the display modes of a liquid crystal display device mentioned above, a liquid crystal (a liquid crystal and a polymer, in the case of a polymer dispersed liquid crystal device) is filled between a pair of substrates, and the liquid crystal is driven by applying an electric field to perform a display operation. In other words, liquid crystal display devices require a pair of substrates as an essential component. This is because in a liquid crystal display device, a light control element driven by applying an electric field is composed of a liquid crystal, which has a flowability, and therefore the liquid crystal needs to be enclosed between a pair of substrates.
However, conventional liquid crystal display devices have the following drawbacks:
1. In recent years, a reduction of the device weight has been demanded in order to apply a liquid crystal display device to personal digital assistants and the like portable information devices. However, at the present state of art, a sufficient reduction in the weight of a liquid crystal display device has not yet been achieved. The reason for this is that the weight of substrates accounts for relatively a large rate of the weight of a liquid crystal display device. Therefore, a liquid crystal display device in which the substrates are eliminated, or a liquid crystal display device composed of only one substrate is desired
2. A wide application of a liquid crystal display device to various appliances has been also demanded. In view of this, if a liquid crystal display device in which substrates are eliminated, i.e., a liquid crystal light control element, can be commercialized as a finished product, the range of application of a liquid crystal display device is broadened by incorporating the liquid crystal light control element into various types of appliances. Accordingly, there is a need for a novel liquid crystal light control element such that a liquid crystal light control element, which is a principle component in a liquid crystal display device, is separated from the liquid crystal display device and independently commercialized as a finished product.
3. In the case of a reflective type liquid crystal display device, a reflector is generally provided outside a substrate. In such a device configuration, there is a problem of parallax in display since the reflector and a liquid crystal layer are apart by a distance equal to the thickness of the substrate.
4. In a configuration such that a liquid crystal is filled between the substrates, when a display panel is depressed by for example an input pen means or the like, an unevenness in display is caused because of the decrease in a cell gap. This results from the fact that liquid crystal is a fluidic matter.
There is also a requirement of the reduction in a device weight for electric devices such as a memory device, an electroluminescent device, an electrophoretic device and the like devices.
SUMMARY OF THE INVENTION
In view of the foregoing and other problems in prior art, it is an object of the present invention to provide a novel liquid crystal light control element that can be incorporated into various appliances.
It is another object of the present invention to provide an optical device having only one substrate and an electric device having only one substrate, in which a reduction in the weight is achieved thereby, and to provide a method of producing such devices.
It is further another object of the present invention to provide an optical device free from an unevenness in display caused by depressing the display panel with an input pen means and the like, and to provide a method of producing the device.
These and other objects are accomplished, in accordance with a first aspect of the invention, by the provision of an optical device comprising a composite provided on a substrate, the composite comprising a polymer resin and a liquid crystal, the optical device wherein:
the liquid crystal is in contact with the substrate on a surface of the composite adjacent to the substrate,
the polymer resin constitutes the other surface of the composite such that a layer of the polymer resin covers the liquid crystal, and
a means for applying an electric field to the liquid crystal is provided.
As described above, the optical device (for example a liquid crystal display device) is configured by using only one substrate, and this achieves a reduction in the weight of the device. In a conventional liquid crystal display device, the use of two substrates is essential, but the weight of the substrates accounts for a large rate in the weight of the device. Accordingly, as in the present invention, a device configuration in which one of the substrates is eliminated achieves a significant reduction in the device weight in comparison with conventional devices.
It is to be noted here that the phrase “the liquid crystal is in contact with the substrate” is intended to include a case in which the liquid crystal is in contact with a thin film such as alignment layer and the like formed on the substrate, as well as a case in which the liquid crystal is directly in contact with the substrate.
In the above configuration, the liquid crystal mentioned above may be formed in the form of a plurality of droplets, and the droplets of the liquid crystal may be juxtaposed on the substrate so as to form a single layer structure.
The liquid crystal in the present invention is so configured that the liquid crystal makes contact with a substrate. Therefore, it should be construed that the term “droplets” is intended to include such configurations as follows:
a configuration in which a bottom surface of the liquid crystal being in contact with the substrate has a substantially planar shape and a surface covering the bottom surface has a curved or hemispherical shape,
a configuration in which the bottom surface of the liquid crystal being in contact with the substrate has a substantially planar shape and the surface covering the bottom surface has a flattened shape, and
a configuration in which a bottom surface of the liquid crystal being in contact with the substrate forms, on the substrate, a polygonal shape such as a hexagon as well as a circular shape.
In addition, the shape of the liquid crystal may be a substantially hemispherical shape or a flattened shape having a substantially uniform thickness, and a diameter of a bottom surface of the liquid crystal may be larger than a thickness of the composite.
When an optical device is such that the liquid crystal has a substantially hemispherical shape as described above, a uniformity of the liquid crystal in the composite is attained. Thereby, an improved display performance is achieved. When an optical device is such that the liquid crystal has a flattened shape having a substantially uniform thickness as above, it is possible to prevent an occurrence of a coloring effect in a peripheral region of the liquid crystal, which is caused by a thickness variation of the liquid crystal.
In addition, a surface of the substrate may be subjected to a wettability controlling treatment, and a surface energy of the substrate may be larger than a surface energy of the liquid crystal. With such configurations, it is po
Kubota Hirofumi
Nakao Kenji
Nishiyama Seiji
Uemura Tsuyoshi
Yamamoto Masao
Matsushita Electric - Industrial Co., Ltd.
Parkhurst & Wendel L.L.P.
Qi Mike
Ton Toan
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