Liquid crystal cells – elements and systems – Particular excitation of liquid crystal – Electrical excitation of liquid crystal
Reexamination Certificate
2000-10-16
2003-12-02
Dudek, James (Department: 2871)
Liquid crystal cells, elements and systems
Particular excitation of liquid crystal
Electrical excitation of liquid crystal
Reexamination Certificate
active
06657681
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a liquid crystal panel, in particular to a liquid crystal panel suitable for use as a liquid crystal display which is capable of simultaneously displaying a static picture and a dot picture on a transparent substrate board.
LCD (Liquid Crystal Device) is usually in a liquid state, but also exhibits a property as a solid crystal. Once an external voltage is applied to such an LCD, orientation of the crystal will change, hence causing a change in both its transparency and its color. When such a kind of liquid crystal device is used to form a display panel, the above-mentioned liquid crystal panel can thus be formed.
Usually, a liquid crystal panel is required to have a light source since the panel itself is not luminescent. In spite of this, a liquid crystal panel is still considered to be superior to a CRT (Cathode Ray Tube) because it is compact in size, light in weight and consumes less electricity. As a result, a liquid crystal panel has often been used as a display monitor in a mobile device such as a note-type personal computer, a PDA (Personal Digital Assistant), and a portable telephone.
However, the above-mentioned liquid crystal panel, especially, a liquid crystal panel for use as a display monitor in a PDA or a portable telephone, usually includes a transparent substrate board on which two different pictures are simultaneously displayed, with one in a static-dislay area (hereinafter, referred to as “picto-display area) and the other in a dot-display area (hereinafter, referred to as “dot-display area). In detail, the static-display area contains stationary icon(s), while the dot-display area contains changing message(s).
FIG. 5
is a cross sectional view showing a conventional liquid crystal panel. As shown in
FIG. 5
, the conventional liquid crystal panel has a liquid crystal layer
11
which is interposed between an upper side transparent glass substrate
18
and a lower side glass substrate
19
, and is functionally divided into a picto-display area A and a dot-display area C. Each of the glass substrates
18
and
19
is provided on the inner side thereof with a transparent electrode layer consisting of ITO (Indium Tin Oxide). Specifically, the picto-display area A involves an upper ITO layer
12
and a lower ITO layer
13
which are faced each other, while the dot-display area C involves an upper ITO layer
14
and a lower ITO layer
15
which are also faced each other.
When an external voltage is applied between mutually faced ITO layers
12
and
13
, and another external voltage is applied between mutually faced ITO layers
14
and
15
, and when the external voltages are made variable so as to change light changing amounts, it is possible to display various desired data on the panel. In this way, when a liquid crystal panel contains the picto-display area A and a dot-display area C, voltages supplied from independently prepared driving sources can be used to effect desired display on the liquid crystal panel.
Usually, the dot-display area C has a larger capacity than that of the picto-display area A. In order to inhibit an electricity consumption on the dot-display area C, this display area is usually driven by a power-saving mold. Namely, if an external voltage of ten and several Volts is continuously applied between the ITO layers
14
and
15
to keep a desired display, and if there is no change in the display content during a predetermined time period, the ITO layers
14
and
15
can then be set at the same potential so as to make the area to be in a forced non-display state. At this time, a (driving) voltage difference will occur between the picto-display area A and the dot-display area C and such a (driving) voltage difference will cause ionic substances contained in the liquid crystal layer
11
to move therebetween, resulting in an undesired mutual interference between the picto-display area A and the dot-display area C.
Namely, if the dot-display area C is fixed at a higher voltage, the ionic substances contained in the liquid crystal layer
11
will be moved from the picto-display area A to the dot-display area C. Consequently, the concentration of the ionic substances in the dot-display area C will be increased, causing a change in the threshold value of the light changing amount in this area. As a result, the dot-display area C becomes darkened while the picto-display area A becomes nicked, making it difficult to obtain a satisfactory picture display.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved liquid crystal panel capable of preventing mutual interference between a plurality of display areas, so as to improve the display quality of the liquid crystal panel, thereby solving the above-mentioned problems peculiar to the above-discussed prior art.
According to the present invention, there is provided a liquid crystal panel comprising: a pair of light transmissible substrate plates; a plurality of liquid crystal display areas controlled and driven by different driving manners; and an electrode sect ion disposed between the plurality of liquid crystal display areas.
According to one aspect of the invention, said different driving manners are different driving voltages.
According to another aspect of the invention, the plurality of liquid crystal display areas include at least one static-display area and at least one dot-display area.
According to a further aspect of the invention, the plurality of liquid crystal display areas include at least one constantly displayed area, and at least one area capable of independently changing-over between a displayed state and a non-displayed state.
According to a still further aspect of the invention, the non-displayed state is a state controlled by a power-saving mode.
According to one more aspect of the invent ion, a driving voltage for driving the electrode section is equal to at least one of the different driving voltages for driving the plurality of different liquid crystal display areas.
According to still one more aspect of the invention, the driving voltage for driving the electrode section is selected in view of the property of a liquid crystal used in the liquid crystal panel.
REFERENCES:
patent: 4412214 (1983-10-01), Tanaka et al.
patent: 5881299 (1999-03-01), Nomura et al.
patent: 5897186 (1999-04-01), Smid
patent: 2 195 195 (1988-03-01), None
Data Sheet, JP 11 281961, Oct. 15, 1999, abstract only.
Furuya Kensei
Kawamura Katsuaki
Arent Fox Kintner & Plotkin & Kahn, PLLC
Dudek James
Pioneer Corporation
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