Liquid crystal cells – elements and systems – Particular structure – Holder – support – frame – or housing
Reexamination Certificate
1997-08-06
2001-09-18
Sikes, William L. (Department: 2871)
Liquid crystal cells, elements and systems
Particular structure
Holder, support, frame, or housing
C349S064000, C349S068000, C349S113000, C349S143000
Reexamination Certificate
active
06292238
ABSTRACT:
FIELD OF THE INVENTION AND RELATED ART
The present invention relates to a reflective-type liquid crystal apparatus suitable for use in portable electronic appliances, such as a mobile computer and a PDA (personal digital assistant), particularly such a reflection-type liquid crystal apparatus capable of providing a uniform display luminance.
Hitherto, various optical display schemes utilizing liquid crystals have been proposed. For example, there has been known a scheme wherein a voltage applied to a pixel is controlled depending on an applied voltage-transmittance curve to obtain a desired level of luminance. This is well-known as a gradation control scheme for an active matrix-type LCD (liquid crystal display) using a TN (twisted nematic) liquid crystal.
On the other hand, there has been a noticeable trend of using a reflection-type liquid crystal apparatus as a portable or handy terminal or a paper-like display in recent years. In such a reflection-type liquid crystal apparatus including no backlight, it is important how to provide a sufficient brightness and a sufficient contrast. Incidentally, an ordinary liquid crystal apparatus using a TN-or STN-liquid crystal requiring two polarizers, a substantial loss of light quantity is caused, thus leaving problems regarding sufficient brightness and contrast.
For this reason, a proposal has been made so as to provide a liquid crystal apparatus capable of realizing little light quantity loss by using a single polarizer in the ECB (electrically controlled birefringence) scheme (Nakamura, et al; 18-th Liquid Crystal Forum, Preprint 3D110, 288 (1992).
On the other hand, in a conventional reflection-type liquid crystal apparatus, a reflection plate of, e.g., a mirror-reflecting aluminum sheet, is disposed on the back side of a liquid crystal panel (liquid crystal device), so that an environmental view is reflected on a display face due to the mirror, and an appropriate luminance cannot be attained in a viewing direction different from the direction in which an external light source is disposed. This can provide a detrimental defect for a portable device which is expected to always provide a uniform luminance even when used in any directions or positions. Further, this poses a problem also for a desktop-type apparatus that an area-type diffusive illumination light source is necessary and should be disposed on a proper position.
In order to alleviate the above-mentioned defect, it has been proposed to apply a diffusion sheet onto a viewer's side substrate. In this case, however, after the reflection, modulated light having passed a polarizer sheet again passes through a diffusion sheet, whereby the picture is blurred thereby. In other words, in order to well display a paper-like white display picture with reflected light from a mirror-face metallic substance, it is desirable to use a diffusion sheet with a large degree of diffusivity, which however causes another problem of blurring character or pictorial images.
SUMMARY OF THE INVENTION
In view of the above-mentioned problems, a principal object of the present invention is to provide a liquid crystal apparatus capable of a bright and good display while preventing reflective display of an environmental view.
Another object of the present invention is to provide a liquid crystal apparatus having a simple structure but allowing a uniform display luminance even when used in directions or positions.
According to the present invention, there is provided a liquid crystal apparatus including a liquid crystal panel comprising a pair of a back side substrate and a viewer's side substrate disposed opposite to each other, and a liquid crystal disposed between the substrates; wherein
the back side substrate is provided with a plurality of scanning electrodes for applying a scanning signal to the liquid crystal,
the viewer's side substrate is provided with a plurality of transparent data electrodes for applying data signals to the liquid crystal, and
the scanning electrodes comprise a reflective and diffusive surface of a metal so as to reflect light incident thereto through the viewer's side substrate.
These and other objects, features and advantages of the present invention will become more apparent upon a consideration of the following description of the preferred embodiments of the present invention taken in conjunction with the accompanying drawings.
REFERENCES:
patent: 4492432 (1985-01-01), Kaufmann et al.
patent: 4712877 (1987-12-01), Okada et al.
patent: 4799776 (1989-01-01), Yamazaki et al.
patent: 5381256 (1995-01-01), Hanyu et al.
patent: 5401330 (1995-03-01), Saito et al.
patent: 5495352 (1996-02-01), Shinjo et al.
patent: 5680233 (1997-10-01), Faris et al.
patent: 5818554 (1998-10-01), Hiyama et al.
patent: 019 208 A1 (1980-11-01), None
patent: 142 326 A1 (1985-05-01), None
patent: 2 028 529 (1980-03-01), None
patent: 06077510 (1994-03-01), None
Mizutani Hidemasa
Okada Shinjiro
Canon Kabushiki Kaisha
Duong Tai V.
Fitzpatrick ,Cella, Harper & Scinto
Sikes William L.
LandOfFree
Reflection-type liquid crystal apparatus does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Reflection-type liquid crystal apparatus, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Reflection-type liquid crystal apparatus will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2439920