Touch Pen Light Modulation for Pressure-Aware Display Sensing
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Solution Overview
Problem
Existing touch sensing technologies in display devices face challenges in accurately determining touch presence and pressure based on light sensing from touch pens, particularly due to interference from external light sources.
Innovation Solution
A touch pen equipped with a light emitting unit, pressure sensor, and modulation unit that adjusts light characteristics (intensity, frequency, and blink patterns) based on pressure sensing information, and a display device with light sensors and a touch processor to analyze these characteristics for precise touch detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If light intensity is increased to improve touch detection signal strength, then touch sensing accuracy is improved, but interference from external light sources increases
Solution Approach 1:
The light emitting unit emits light in periodic blink patterns rather than continuously. The modulation unit controls the light to blink at specific frequencies and patterns that encode touch state information. This periodic emission reduces the window for external light interference while maintaining sufficient signal strength for detection.
Solution Approach 2:
The system dynamically changes light parameters (intensity, blink frequency, blink pattern) based on pressure sensing information. When touch pressure is detected, the light emitting unit adjusts its characteristics to emit light with specific patterns that indicate touch state. This parameter modulation allows the system to distinguish between touch states while managing external light interference through controlled emission patterns.
2Reliability
If light emission is continuous to ensure constant signal availability, then touch detection reliability is improved, but energy consumption increases
Solution Approach 1:
The light emitting unit operates in periodic blink cycles rather than continuous emission. During each cycle, light is emitted for a specific duration then turned off. This periodic operation maintains touch detection capability during active cycles while significantly reducing energy consumption during off cycles, achieving a balance between reliability and energy efficiency.
Solution Approach 2:
The pressure sensor and modulation unit work together to control light emission based on actual touch conditions. When no touch is detected, the light emitting unit remains inactive or emits minimal light. When touch pressure is detected, the system activates light emission with appropriate patterns. This on-demand operation reduces unnecessary energy consumption while maintaining detection reliability when needed.
3Loss of information
If light blinking frequency is increased to encode more touch information, then information transmission capability is improved, but difficulty in detecting and measuring increases
Solution Approach 1:
The system uses periodic blinking at specific frequencies to encode touch information. Different blink frequencies or patterns represent different touch states or pressure levels. The periodic nature provides clear temporal markers that make it easier for the display device to detect and measure the light characteristics, even at higher frequencies, by providing distinct on/off transitions for analysis.
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
Enhances touch sensing accuracy by distinguishing touch states and pressure levels through controlled light emission patterns, reducing interference from external light and improving touch detection reliability.
Implementation Method 1
a light emitting unit configured to generate light for touch detection
Implementation Method 2
a pressure sensor configured to generate pressure sensing information by sensing a pen pressure
Implementation Method 3
a display device including: a display panel including a plurality of light sensors that sense light irradiated from a touch pen
Data Source
AI summary
A touch pen includes a light emitting unit configured to generate light for touch detection, a pressure sensor configured to generate pressure sensing information by sensing a pen pressure, and a modulation unit configured to determine a characteristic of the light generated by the light emitting unit, based on the pressure sensing information.