Abstract: A suspension system for a differential-pressure touch sensitive panel suspended over force sensors, for use in either fixed or mobile devices such as point of sales terminals, kiosks, laptops, monitors, PDAs, cell phones, UMPCs and more. In one embodiment, a number of leaf springs are attached directly to the touch lens at both ends and attached directly to the underlying housing at the center, effectively pulling the leaf spring down at the center into a concave arc. The spring bias preloads the touch lens downward against the force sensors. The leaf springs bring the touch lens into a fixed state in the xy-plane and resist translation; however, the touch lens remains free to float against the bias of the leaf spring(s) without any frictional physical contact along the z-axis.

Abstract: A touch screen assembly for an electronic device such as a cell phone or PDA. The touch screen assembly generally comprises a floating lens suspended over the display and, optionally, the keypad to allow a degree of freedom. An underlying thin connecting layer such as a flex film is attached beneath the floating lens, and a plurality (for example, four) differentially-mounted pressure sensors are mounted beneath the floating lens and are electrically connected to the electronic device via the flex film. The pressure sensors are differentially positioned along an x- and y-axis for registering a pressure z from a touch to the lens at each of the four positions, to provide four data sets (x1-4, y1-4, z1-4). Control software then interprets the exact touch-coordinate from the four data sets and generates a control signal. An optional haptic response generator and/or motion sensor are also contemplated.

Abstract: A suspension system for a differential-pressure touch sensitive panel suspended over force sensors, for use in either fixed or mobile devices such as point of sales terminals, kiosks, laptops, monitors, PDAs, cell phones, UMPCs and more. In one embodiment, each side of the lens is encircled and supported by a looped string, monofilament or flexible wire, which is then looped around the back cover or base plate, forming a figure-8. The figure 8-loops bring the lens into a fixed state in the xy-plane without the addition of any friction causing physical contact. Other alternative implementations include continuous suspensions, bender suspensions and 3-dimensional force suspensions. Moreover, the present invention proposes the use of a flexible padding under the force sensors to allow the sensors to be slightly preloaded, which reduces the dependency on extremely tight mechanical tolerances.

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.