Integrated Touch Force Sensor Shared Circuitry
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Solution Overview
Problem
Touch sensitive devices that integrate both touch and force sensing mechanisms face challenges in reducing device size and power consumption due to the need for separate circuitry for each sensing type.
Innovation Solution
The integration of force sensors with touch sensors using shared touch circuitry, where touch stimulation signals are used to drive force sensors, reducing noise and minimizing circuitry space and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate circuitry is used for touch sensing and force sensing, then both sensing functions can be provided, but device size and power consumption increase
Solution Approach 1:
The patent combines touch sensing and force sensing into a single integrated sensor that uses shared circuitry. The force sensor and touch sensor are merged into one device with common readout electronics, eliminating the need for separate circuit boards and reducing overall device footprint while maintaining both sensing capabilities.
Solution Approach 2:
The integrated sensor serves multiple functions simultaneously - it detects both touch events and force events using the same physical structure and shared electronics. The sensor can operate in different modes (touch mode and force mode) depending on the type of input detected, providing universal input detection capability.
2Adaptability or versatility
If separate circuitry is used for touch sensing and force sensing, then both sensing functions can be provided, but power consumption increases
Solution Approach 1:
The patent merges the readout electronics for both touch and force sensing into a single shared circuit system. The same amplifier, analog-to-digital converter, and processing logic are used for both sensing types, eliminating redundant power consumption from duplicate electronic components and reducing overall power requirements.
Solution Approach 2:
The sensor system provides universal input detection (both touch and force) through a single multi-functional sensing mechanism that shares all electronic resources. This eliminates the need for separate power supplies, clock signals, and processing channels that would be required for independent touch and force sensors.
3Measurement precision
If touch stimulation signals are used to drive force sensors, then noise is reduced, but signal processing complexity increases
Solution Approach 1:
The same stimulation signal generation circuitry and readout electronics are used for both touch sensing and force sensing operations. The system can switch between sensing modes using the same hardware resources, which simplifies the overall design compared to having separate dedicated circuits for each sensing type.
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
This approach allows for multiple input mechanisms without increasing device size or power consumption, enabling seamless operation of touch and force sensing capabilities while reducing noise and enhancing signal resolution.
Implementation Method 1
US 2010/0123686 A1 discloses a piezoresistive force sensor integrated in a display
Implementation Method 2
US 6,492,979 B1 discloses a dual sensor touchscreen utilizing projective-capacitive and force touch sensors
Data Source
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Figure 3A~3B
Figure 4A~4B
AI summary
A force sensor interface in a touch controller of a touch sensitive device is disclosed. The force sensor interface can couple to touch circuitry to integrate one or more force sensors with touch sensors of the device. The force sensor interface can include one portion to transmit stimulation signals generated by the touch circuitry to the force sensors to drive the sensors. The interface can also include another portion to receive force signals, indicative of a force applied to the device, from the force sensors for processing by the touch circuitry. The device can use the touch circuitry to concurrently and seamlessly operate both the force sensors and the touch sensors.