Acoustic Touch Detection Using Signal Transmitting Stylus
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Solution Overview
Problem
Current touch detection technologies, such as capacitive, resistive, APR, and SAW, face challenges in accurately distinguishing between finger and stylus inputs, are costly, and affect the optical transparency of screens, making them inefficient for larger screens and multi-touch inputs.
Innovation Solution
A system using a propagating medium that receives signals from both stylus and finger inputs, where a stylus transmits a digital binary signal and a receiver detects the location by processing timing differences across the medium, allowing for precise detection without additional costly hardware and maintaining screen clarity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistive or capacitive touch detection technology is used, then touch input detection is achieved, but the glass screen clarity is reduced and manufacturing costs increase
Solution Approach 1:
The patent replaces traditional mechanical/optical touch detection systems (resistive/capacitive layers on glass) with an acoustic wave-based detection system using surface acoustic waves (SAW) and bulk acoustic waves (BAW). This substitution eliminates the need for conductive coatings on the glass screen, thereby maintaining screen clarity while achieving reliable touch input detection through acoustic signal analysis
Solution Approach 2:
The patent introduces acoustic waves (both surface acoustic waves and bulk acoustic waves) as an intermediary medium to detect touch inputs. Instead of directly detecting mechanical pressure or electrical charge changes on the glass surface, the system uses acoustic wave propagation and reflection patterns as a mediator to indirectly detect touch location and characteristics, preserving glass optical properties
2Reliability
If the entire glass screen is coated with conductive material for capacitive touch detection, then touch input detection is enabled, but manufacturing and component costs become prohibitively expensive for larger screens
Solution Approach 1:
The patent replaces the expensive full-screen conductive coating approach with an acoustic wave detection system that uses piezoelectric transducers positioned at specific locations (edges or corners). This substitution eliminates the need for expensive large-area conductive material deposition while maintaining touch detection capability through acoustic signal analysis
Solution Approach 2:
The patent segments the touch detection function from the glass screen itself, using separate piezoelectric transducer components positioned at specific locations rather than requiring the entire screen surface to have active detection material. This segmentation reduces material costs and simplifies manufacturing for large screens
3Measurement precision
If surface acoustic wave technology is used to detect touch input, then touch detection accuracy is improved, but the system cannot distinguish between finger and stylus inputs and requires specialized hardware
Solution Approach 1:
The patent makes the acoustic wave detection system universal by enabling it to detect multiple types of touch inputs (finger, stylus, multiple simultaneous touches) using the same hardware infrastructure. The system analyzes acoustic wave characteristics (amplitude, frequency, phase, timing) to differentiate between input types, eliminating the need for specialized hardware for different input devices
Solution Approach 2:
The patent uses parameter analysis of acoustic waves (amplitude, frequency, phase, arrival time) to distinguish between different touch input types. By monitoring changes in these acoustic parameters, the system can identify whether a touch is from a finger or stylus and detect multi-touch scenarios without requiring different hardware for each input type
4Reliability
If ultrasonic waves are sent in a guided pattern using reflectors, then touch detection capability is achieved, but costs increase and implementation becomes difficult
Solution Approach 1:
The patent replaces the complex mechanical reflector system with piezoelectric transducers that directly generate and detect acoustic waves. This substitution eliminates the need for precise mechanical reflector positioning and guided wave patterns, simplifying implementation while maintaining touch detection capability through direct acoustic coupling
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 accurate and cost-effective detection of touch inputs, including multi-touch and gestures, on larger surfaces without compromising screen clarity, effectively distinguishing between stylus and finger inputs.
Implementation Method 1
a tip of the stylus device vibrates the propagating medium at its contact location to propagate the signal of the transmitter of the touch input indicator device through the propagating medium
Implementation Method 2
A receiver is coupled to the propagating medium. The receiver is configured to receive the signal from the touch input indicator device that has been propagated through the propagating medium
Data Source
AI summary
A touch input provided by a touch input indicator device is received on a propagating medium of a receiving device. The touch input indicator device includes a transmitter that transmits a signal to the propagating medium when the touch input indicator device contacts the propagating medium. The signal encodes a digital binary data identifying the signal. The signal that has been propagated through the propagating medium is received at a receiver of the receiving device. The receiver is coupled to the propagating medium. The digital binary data is detected in the received signal. Based at least in part on the detection of the digital binary data, the touch input provided by the touch input indicator device is detected.