Force sensing data input device responding to the release of pressure force
First Claim
1. A force-sensing data input device for use with a visual display, comprising:
- a rigid member including a flange portion, side walls extending from said flange portion and an arcuate transparent faceplate joined to said flange portion via said side walls and generally recessed from said flange portion;
a rigid mounting frame having a central opening for receiving portions of said side walls and said recessed faceplate therethrough, such that said faceplate may closely follow the surface contour of said display and said flange portion confronts said rigid mounting frame;
a plurality of force-sensing means, each being disposed at a respective predetermined location between said rigid member flange portion and said rigid mounting frame, said force-sensing means holding separated said flange portion and said rigid mounting frame;
said force-sensing means being positioned in wells formed in a side of said rigid mounting frame facing said flange, in a manner such that at least interference-sensitive portions of the same are effectively shielded from stray electromagnetic radiation, said rigid mounting frame being formed of a conductive material; and
spring means for urging said flange portion and said rigid mounting frame toward one another.
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Accused Products
Abstract
A force-sensing data input device of very high accuracy and a method for operating such a force-sensing input device. An input surface is provided having a transparent faceplate which conforms to the display surface of a display device, such as a cathode-ray tube display, with which the input device is used. A flange of the input surface is separated from a rigid, conductive reference surface or frame by force-sensing piezoelectric transducers, preferably constructed of lead-zirconium titanate. At least portions of the piezoelectric transducers which are sensitive to electromagnetic interference are located within wells formed in the frame so as to be shielded. Preferably, four piezoelectric transducers are provided, one at each corner of a rectangular opening formed in the frame. To determine the point of application of force on the input surface, the outputs of the four transducers are first summed. To constitute a valid data entry attempt, the sum must exceed a first threshold while the user is pushing on the input surface. When the user releases his finger, a peak of the sum is detected, which is of opposite polarity from the polarity of the sum for the pushing direction. The individual outputs of the four sensors at the time that the peak of the sum occurs are used to calculate the point of application of the force.
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Citations
30 Claims
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1. A force-sensing data input device for use with a visual display, comprising:
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a rigid member including a flange portion, side walls extending from said flange portion and an arcuate transparent faceplate joined to said flange portion via said side walls and generally recessed from said flange portion; a rigid mounting frame having a central opening for receiving portions of said side walls and said recessed faceplate therethrough, such that said faceplate may closely follow the surface contour of said display and said flange portion confronts said rigid mounting frame; a plurality of force-sensing means, each being disposed at a respective predetermined location between said rigid member flange portion and said rigid mounting frame, said force-sensing means holding separated said flange portion and said rigid mounting frame;
said force-sensing means being positioned in wells formed in a side of said rigid mounting frame facing said flange, in a manner such that at least interference-sensitive portions of the same are effectively shielded from stray electromagnetic radiation, said rigid mounting frame being formed of a conductive material; andspring means for urging said flange portion and said rigid mounting frame toward one another. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 28)
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13. A method for determining a point of application of force on a force-sensing data input device in which a plurality of force-sensing elements are disposed at predetermined positions between an input surface and a reference surface, comprising the steps of:
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summing output signals from each of said force-sensing means; detecting a peak value of said sum for a polarity of said sum corresponding to release of said force; and determining said position of application of said force in accordance with the values of said output signals of each of said force-sensing means at the time said peak value is detected. - View Dependent Claims (14, 15)
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16. A method for determining a point of application of force on a force-sensing data input device in which a plurality of force-sensing means are disposed at predetermined positions between an input surface and a reference surface, comprising the steps of:
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(a) summing outputs from each of said force-sensing means; (b) detecting whether said sum of said outputs of said force-sensing means exceeds a first predetermined threshold during a time of pushing by said force; (c) if and only if said first threshold is exceeded, determining whether said sum of said outputs of said force-sensing means exceeds a second predetermined threshold of a polarity opposite said first predetermined threshold during release of said force; (d) if and only if said second threshold is exceeded, detecting a subsequent peak magnitude of said sum of said outputs of said force-sensing means; and (e) determining said point of application of said force in accordance with values of said outputs from said force-sensing means present at the time said peak magnitude of said sum of said outputs is detected. - View Dependent Claims (17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
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29. In a force sensitive input device for translating the location of a localized data input force applied to an essentially planar area member into data for machine computation, wherein said planar area member is supported with respect to a reference at at least three points by separate force sensors,
the improvement comprising in combination means for establishing a sum of the output signals from each of said force sensors, means for detecting a peak value of said sum in a polarity corresponding to a release of said data input force, and means for determining a position of application of said data input force in accordance with a value of an output signal from each said force sensor at a time of detection of said peak value.
Specification