Stylus Variable Impedance Pressure Signal Transmission
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Solution Overview
Problem
Current touch panel systems lack an effective method for transmitting precise pressure information from active styli, leading to inaccuracies in pressure detection and control.
Innovation Solution
A stylus design incorporating a first component with variable impedance and a second component with fixed impedance, both encoded with pseudo-random number (PN) codes, which transmit signals orthogonally to a conductive tip section, allowing for precise pressure information transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single component transmits electrical signals from the stylus, then the device structure is simple, but pressure information transmission precision is insufficient
Solution Approach 1:
The patent divides the signal transmission function into two separate components: a first component with variable impedance that changes with pressure, and a second component with fixed impedance. Each component transmits signals through separate conductive paths to the touch panel, enabling the system to distinguish pressure information by comparing the electrical characteristics of the two paths. This segmentation resolves the contradiction by providing sufficient pressure precision through dual-path transmission while keeping each individual component relatively simple.
2Adaptability or versatility
If multiple styli are used simultaneously, then user versatility is improved, but code conflicts occur between styli
Solution Approach 1:
The patent introduces orthogonal PN codes as an additional dimension for signal differentiation. Each stylus is assigned a unique orthogonal PN code sequence, allowing multiple styli to transmit signals simultaneously on the same physical medium without interference. The orthogonality property ensures that signals from different styli can be independently decoded at the touch panel, resolving the code conflict issue while maintaining full multi-stylus versatility.
3Measurement precision
If pressure information is transmitted without encoding, then transmission speed is fast, but signal accuracy deteriorates due to interference
Solution Approach 1:
The patent applies PN code encoding to the electrical signals before transmission through the conductive paths. This preliminary encoding action embeds unique identification sequences in the signals from each component, enabling the touch panel to accurately distinguish and decode pressure information even in the presence of electromagnetic interference or noise. The encoding process adds minimal overhead while dramatically improving signal accuracy and reliability.
Data Source
AI summary
The present invention provides a stylus for transmitting electrical signals carrying pressure information, comprising: a first component with variable impedance reflecting a pressure, wherein the first component is configured for receiving first signals encoded by a pseudo-random number (PN) code in a first time period; a second component with fixed impedance, wherein the second component is configured for receiving second signals encoded by the PN code in a second time period; and a conductive tip section configured for: receiving the first signals from the first component in the first time period; receiving the second signals from the second component in the second time period; transmitting electrical signals which is composed of the first signals in the first time period; and transmitting electrical signals which is composed of the second signals in the second time period.