Active Pen Signal Encoding via Duty Ratio Modulation

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Display devices face challenges in efficiently providing both finger touch and pen touch functions while accurately recognizing pen information, as existing technologies struggle to rapidly transmit a large amount of pen information within a limited time, leading to delayed or incomplete recognition of pen inputs.

Innovation Solution

The implementation of an active pen system that uses a touch display device with a touchscreen panel and a touch circuit, which employs various signal timing strategies, such as duty ratio and amplitude variable control, to rapidly transmit pen information by utilizing multiple states and symbol values, allowing for increased data transmission within a predetermined limited time.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of information

If a large amount of pen information is transmitted, then the completeness of pen information recognition is improved, but the transmission time increases

Engineering Contradiction:
Improvecompleteness of pen information recognitionVSAvoidpen information transmission time
Core Design Contradiction:
Loss of informationVSLoss of time

Solution Approach 1:

The patent applies periodic action by using pulse signals with different duty ratios to transmit pen information. The duty ratio of the pulse signal is varied periodically to encode different types of pen information (e.g., button press, eraser mode, tilt angle), allowing multiple information states to be transmitted through periodic variations in a single signal waveform without requiring separate transmission channels or extended time periods.

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent employs parameter changes by modifying the duty ratio parameter of the pulse signal to encode different pen information states. By changing the duty ratio (the ratio of pulse width to period), the system can represent multiple information types within the same time frame, thus transmitting more information without increasing transmission time. This parameter modulation allows efficient encoding of complex pen states.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If multiple pen functions are provided, then the versatility of the touch display device is improved, but the complexity of signal transmission increases

Engineering Contradiction:
Improvepen function versatilityVSAvoidsignal transmission complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements universality by designing a single pulse signal transmission channel that can carry multiple types of pen information through duty ratio modulation. The same signal line and communication protocol are used for various pen functions (button press, eraser, tilt sensing, pressure detection), eliminating the need for separate dedicated channels for each function and reducing overall system complexity despite supporting multiple pen capabilities.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent uses parameter changes (duty ratio variation) as a universal encoding mechanism for different pen functions. By systematically varying the duty ratio parameter, the system can distinguish between different pen states and functions using the same transmission infrastructure, thereby managing complexity through a unified parameter-based approach rather than requiring separate complex signaling schemes for each function.

Inventive Principle:
Principle #35Parameter changes

3Productivity

If pen information is transmitted rapidly, then the recognition speed is improved, but the accuracy of information detection may deteriorate

Engineering Contradiction:
Improvepen information recognition speedVSAvoidpen information detection accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The patent incorporates feedback mechanisms where the touch display device sends beacon signals to the active pen, and the pen responds with pulse signals containing its information. This bidirectional feedback loop allows for verification and error correction, ensuring that even rapid transmissions are accurately received and interpreted. The feedback system enables real-time adjustment and confirmation of transmitted data, maintaining accuracy despite high transmission speeds.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The patent uses periodic pulse signals with defined duty ratios to encode pen information, creating regular, predictable transmission patterns. This periodic structure facilitates synchronized reception and analysis by the touch display device, allowing rapid yet accurate detection by establishing clear temporal patterns that are easy to track and interpret even at high transmission rates.

Inventive Principle:
Principle #19Periodic action

Data Source

PatentEP3422160B1Touch display device, pen, touch system, touch circuit, and pen recognition method
Publication Date: 2022.10.12 LG DISPLAY CO LTD
  • EP3422160B1 patent drawingFigure 1
  • EP3422160B1 patent drawingFigure 2
  • EP3422160B1 patent drawingFigure 3

AI summary

A touch display device (10) may include: a panel (110) including a plurality of touch electrodes (TE), and a touch circuit (300) configured to: transfer a panel driving signal (PDS1, PDS2, PDS3) to the panel (110), and receive a pen information signal (PINFO), output from a pen (20) in response to the panel driving signal (PDS1, PDS2, PDS3), through the panel (110), each of the panel driving signal (PDS1, PDS2, PDS3) and the pen information signal (PINFO) including a plurality of pulses, the pen information signal (PINFO) including one or more state sections among: an in-phase state section including pulses in phase with the pulses of the panel driving signal (PDS1, PDS2, PDS3), an antiphase state section including pulses having a different phase from the pulses of the panel driving signal (PDS1, PDS2, PDS3), and a passive state section distinguished from the in-phase state section and the antiphase state section.