Touch Panel Optical Deflection for Passive Pressure Sensing
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Solution Overview
Problem
Existing touch-sensitive apparatuses rely on complex input devices with integrated sensors, limiting user choice and hindering the development of highly customizable and intuitive touch systems.
Innovation Solution
A touch-sensing apparatus that detects touch pressure by determining the difference in received light between panel deflections using emitters and detectors arranged along the perimeter, allowing for pressure detection based on panel deflection without requiring sensors in the touch object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex input devices with integrated sensors are used for pressure detection, then pressure control capability is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical pressure sensors integrated in styluses with an optical measurement system. The touch panel itself becomes the sensing element by detecting panel deflection through optical paths between emitters and detectors arranged at the perimeter. This substitution eliminates the need for complex integrated sensors in input devices while maintaining pressure detection capability.
Solution Approach 2:
The touch panel serves multiple functions: it acts as both the display surface and the pressure sensing element. By detecting deflection of the panel itself through the optical system, the same panel structure provides both visual output and tactile input capabilities, eliminating the need for separate sensing mechanisms.
2Measurement precision
If complex input devices with integrated sensors are used, then pressure control capability is improved, but user choice and customization are limited
Solution Approach 1:
The system allows any object that can deflect the panel to serve as a valid input device. Whether it's a finger, a passive stylus, or other objects, the panel's deflection response provides pressure information. This universality greatly expands user choice and enables highly customizable touch interactions without requiring specialized sensor-equipped devices.
Solution Approach 2:
The panel itself provides the sensing function through its inherent mechanical properties. The panel's deflection under touch pressure is directly measured by the optical system, allowing passive objects without integrated sensors to function as input devices. The system serves itself by using the panel's physical response as the measurement mechanism.
3Ease of operation
If light paths extend across the panel above the touch surface, then touch detection is enabled, but pressure detection capability is reduced
Solution Approach 1:
The system dynamically measures the panel's deflection state by detecting changes in optical path geometry. As the panel deflects under pressure, the position and shape of the light paths change. By measuring these dynamic changes in the optical paths between emitters and detectors, the system can determine both touch location and pressure magnitude.
Solution Approach 2:
The optical paths serve as intermediaries that translate panel deflection into measurable signals. The emitters and detectors at the perimeter use the panel itself as part of the optical path, so that panel deformation directly affects the light transmission characteristics, providing a sensitive measure of pressure without requiring additional sensors.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Enables intuitive touch interaction with passive objects, reduces complexity and cost, and improves touch input accuracy, particularly in modeling pressure variations for writing or drawing.
Implementation Method 1
a set of optical emitters are arranged around the perimeter of a touch surface of a panel to emit light that is reflected to propagate across the touch surface. A set of light detectors are also arranged around the perimeter of the touch surface to receive light from the set of emitters from the touch surface.
Implementation Method 2
the detectors are arranged to receive at least part of said light as detection light, wherein the touch sensing apparatus is configured to determine a difference in the received detection light between deflection of the panel from a first position (p1) to a second position (p2)
Data Source
AI summary
A touch sensing apparatus is disclosed for detecting touch pressure, comprising a panel that defines a touch surface, the panel having a perimeter, a plurality of emitters arranged along the perimeter, wherein the emitters emit light across the panel, a plurality of detectors arranged along the perimeter, whereby the detectors are arranged to receive at least part of said light as detection light, wherein the touch sensing apparatus is configured to determine, as a touch object deflects the panel along a normal of the touch surface, a difference in the received detection light between deflection of the panel from a first position (p1) to a second position (p2) along the normal, and determine a pressure of the touch object against the touch surface based on said difference.