Liquid crystal display device

Details Liquid crystal display device Liquid crystal display device

1998-08-26

2001-07-10

Dudek, James A. (Department: 2871)

Liquid crystal cells, elements and systems

Liquid crystal system

Liquid crystal writing tablet

Reexamination Certificate

active

06259490

ABSTRACT:

DETAILED DESCRIPTION OF THE INVENTION
1. Field of the Invention
The present invention relates to a liquid crystal display device including a means for detecting a position to which a pen or a finger of an operator touches.
2. Background Art
Display devices using various schemes for detecting a touched position as described in NIKKEI BYTE, p.285, May 1998, and Monthly Display pp.76-103, July 1996. Such schemes include an analog capacity coupling scheme, a resistive film scheme, an infrared ray scheme, an ultrasonic wave scheme, etc. Such position detecting mechanisms are typically referred to as touch panels. To use the touch panel in the display device, a glass substrate used as the touch panel is overlapped on a screen of an image display device, such as a CRT, as in the case of an ATM (automatic teller machine). Accordingly, the size of the touch panel is larger than the size of the image display device by at least the size of touch sensors.
In the resistive film scheme, two resistive films are disposed to face each other, and a touched position is detected by contacting portions of both the resistive films contacted by a pen. In one way of the resistive film scheme, a resistive sheet made of two adhered resistive films is adhered on the screen of the image display device by an adhesive. However, it is impossible to achieve a high resolution in the resistive film scheme. A Japanese Published Unexamined Patent Application 9-322013 discloses a remote control unit in which a pressure sensitive film forming a resistive pressure sensor is integrally overlapped on the liquid crystal display device with a detecting precision of about 1 mm.
A Japanese Published Unexamined Patent Application 46-21879 discloses an electrical tablet device including an electrically conductive square sheet having electrically conductive electrode devices provided at four corners.
U.S. Pat. No. 4,198,539 discloses a touch sensor of the analog capacity coupling scheme and a linearization pattern provided on an outer peripheral portion.
U.S. Pat. No. 5,365,461 discloses an alternate use of a finger and a pen as an input device of the touch sensor of the analog capacity coupling scheme.
To combine a prior touch sensor with a portable type image display device such as a liquid crystal display device, the touch sensor has been overlapped on a screen of the liquid crystal display device. The problem caused in this case is that a thickness and weight of the liquid crystal display device become large due to a thickness of the touch sensor itself. In addition, the image quality is degraded.
SUMMARY OF THE PRESENT INVENTION
The present invention relates to a liquid crystal display device which comprises: a liquid crystal layer; a pair of substrates, one of the substrates being disposed at one side of the liquid crystal layer and the other of the substrates being disposed at the other side of the liquid crystal layer; a polarizer disposed on the outside of one of the substrates; and a an electrically conductive film, disposed between the polarizer and substrate, for detecting position of an input device based upon signals applied to the film. The film may be integrally disposed on the substrate or integrally disposed on the polarizer. A linearization pattern may be formed on an outer peripheral region of the film. The input device may be a human finger or a touch pen.
Further, the present invention relates to the liquid crystal display device, wherein the film is integrally disposed on the substrate, and the size of the polarizer adjacent to the substrate is smaller than the size of the film.


REFERENCES:
patent: 4198539 (1980-04-01), Pepper, Jr.
patent: 5365461 (1994-11-01), Stein et al.
patent: 5465103 (1995-11-01), Yoshioka
patent: 59-33076 (1984-02-01), None
patent: 61-174587 (1986-08-01), None
patent: 62-86328 (1987-04-01), None
patent: 62-84020 (1987-05-01), None
patent: 62-181926 (1987-11-01), None
patent: 5-19233 (1993-01-01), None

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