Computer graphics processing and selective visual display system – Display peripheral interface input device – Touch panel
Reexamination Certificate
1999-05-20
2001-12-25
Lao, Lun-Yi (Department: 2673)
Computer graphics processing and selective visual display system
Display peripheral interface input device
Touch panel
C345S173000, C178S018050, C178S018030
Reexamination Certificate
active
06333736
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a detector constructed from fabric having electrically conductive elements to define at least two electrically conductive planes.
INTRODUCTION TO THE INVENTION
A fabric touch sensor for providing positional information is described in U.S. Pat. No. 4,659,873 of Gibson. The sensor is fabricated using at least one resistive fabric layer in the form of conducting threads. This fabric is constructed using either uni-directional threads or crossed threads formed by overlaying one set with another or weaving the two sets together. The fabric is separated from a second resistive layer to prevent unintentional contact by separators in the form of non-conducting threads, insulator dots or with an air gap. Both resistive layers are fabrics formed from conductive threads such that no pre-forming is required in order to adapt the sensor to a contoured object.
A problem with the sensor described in the aforesaid United States patent is that it is only capable of identifying the location of the mechanical interaction and cannot provide additional information about the interaction.
A touch sensor for providing positional information is described in U.S. Pat. No. 4,487,885 of Talmage, which also provides a signal dependent upon the pressure or force applied. However, the sensor described is made from a printed circuit board and a flexible sheet of rubber, elastomer or plastic and as such it does not have the many physical qualities that a fabric may provide.
An improvement to this proposal is disclosed in the applicant's copending British patent application number 98 20 902.6 in which there is provided a position detector constructed from fabric having electrically conductive elements, comprising at least two electrically conductive planes. A potential is applied across at least one of the planes to determine the position of a mechanical interaction. In addition, a second electrical property is determined, such as current, to identify additional properties of the mechanical interaction, such as an applied force, an applied pressure or an area of contact.
The position detector, constructed from fabric, facilitates bending and folding operations. However, a problem with the disclosed construction is that the electrical characteristics of the detector are unreliable if the detector planes are folded or distorted beyond modest operational conditions. Certain folding or bending of the sensor can cause pressures within the fabric similar in magnitude to those pressures desired to be measured, leading to undesirable output response characteristics.
A further limitation of the aforementioned disclosures, is that switching arrangements employed to perform position detection may result in undesirable radio frequency emissions. In the particular case of a fabric position detector, It may be desirable to have the fabric in close proximity to an operator, possibly being worn as an article of clothing. Under these circumstances, radio frequency emissions must be kept to a level that may not be achievable using the disclosed detector arrangements.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a method of detecting the position of a mechanical interaction in a sensor constructed from fabric, wherein a substantially constant electric current is established through said elements, including steps of measuring a first electrical potential developed in a first plane in response to said current; measuring a second electrical potential developed in a second plane in response to said current; and processing said measurements to identify a position of said mechanical interaction.
REFERENCES:
patent: 3911215 (1975-10-01), Hurst et al.
patent: 4220815 (1980-09-01), Gibson et al.
patent: 4503286 (1985-03-01), Kubo et al.
patent: 4570149 (1986-02-01), Thornburg et al.
patent: 4659873 (1987-04-01), Gibson et al.
patent: 4687885 (1987-08-01), Talmage, Jr. et al.
patent: 4707845 (1987-11-01), Krein et al.
patent: 4798919 (1989-01-01), Miessler et al.
patent: 4897511 (1990-01-01), Itaya et al.
patent: 4963703 (1990-10-01), Phillips et al.
patent: 5008497 (1991-04-01), Asher
patent: 5159159 (1992-10-01), Asher
patent: 5262778 (1993-11-01), Saunders
patent: 5324895 (1994-06-01), Inamori et al.
patent: 5453941 (1995-09-01), Yoshikawa
patent: 5686705 (1997-11-01), Conroy et al.
patent: 5815139 (1998-09-01), Yoshikawa et al.
patent: 5852260 (1998-12-01), Yoshikawa
patent: 0032013 A1 (1981-07-01), None
patent: 0134853 A1 (1985-03-01), None
patent: 0161895 A2 (1985-11-01), None
patent: 0172783 A2 (1986-02-01), None
patent: 1308575 (1973-02-01), None
patent: 1331942 (1973-09-01), None
patent: 2115555 A (1983-09-01), None
patent: 2341929 A (2000-03-01), None
Electrotextiles Company Limited
Lao Lun-Yi
Nixon & Vanderhye P.C.
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