US 8,026,906 B2Granted

Integrated force sensitive lens and software

AssigneeF-Origin, Inc.

InventorsAnders L Mölne, Joseph Carsanaro, Toni Leinonen, Konstantin Klimov

Life of this patent

Estimating the term…

Loading patent…

Abstract

A software compensation method that allows a touch sensitive display to be built using low-cost FSR force sensors The compensation method comprises an array of functional compensation modules including filtering, voltage conversion, temperature compensation, humidity compensation, sensor calibration, sensor reading linearization, auto calibration, positioning determination and finally end-user and mechanical calibration. The array of compensation modules can bring system accuracy from a non-compensated average positioning error in the 25% to 50% range, down to aN end-user acceptable range of 0% to 5%. The increased positioning accuracy makes it possible to use FSRs as opposed to traditional piezoresistive based touch screen sensors.

Claims20

Dependent claims

A method for improving touch precision of an electronic device comprising a touch screen having a plurality of differential-force sensors mounted there beneath, a processor in communication with said plurality of differential-force sensors, and memory accessible by said processor, comprising the steps of:

quantitatively determining coefficients of a polynomial force-resistance equation defining a non-linear force-resistance curve for said plurality of sensors;
storing said determined coefficients in said memory;
polling each of said plurality of differential-force sensors for a corresponding raw sensor reading and storing said raw sensor readings in said memory;
calculating in said processor an actual force value from each of said plurality of differential force sensors using said polynomial force-resistance equation, determined coefficients, and raw force sensor readings, for linearization and homogenization of said raw force sensor readings;
and
calculating in said processor a coordinate position of a force applied to said touch screen based on all of the actual force values calculated for all of said plurality of differential force sensors.

3 more elements

A differential-force touch screen display for a portable electronic device having improved touch precision, comprising:

a display module having a touch panel;
a plurality of FSR force sensors in operative contact with said touch panel;
a processor in communication with said FSR force sensors, said processor having accessible memory containing predetermined coefficients of a sensor-specific force-resistance curve for each of said plurality of FSR force sensors;
a software program resident in said accessible memory and executable by said processor, said software program comprising a module for linearization and homogenization of sensor data using a sensor-specific force-resistance curve for each of said plurality of FSR force sensors;
whereby an actual force experienced by each of said plurality of FSR force sensors is calculated by said software program applying said predetermined coefficients retrieved from said accessible memory to said sensor-specific force-resistance curve for each of said plurality of FSR force sensors.

2 more elements

Dependencies are inferred from the claim text.

Facts

Application: 12/009,964Filed 23 Jan 2008 · continuation in part
Priority: 7 Sep 2007
Published: US 2009/0066673 A112 Mar 2009
Granted: 27 Sep 2011
Term ends: Not estimatedThe source records don’t support an estimate.

Classification3 codes

G06F 3/0414
Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means: using force sensing means to determine a position
G06F 3/0418
Control or interface arrangements specially adapted for digitisers: for error correction or compensation, e.g. based on parallax, calibration or…
G06F
Computing and data processing