Smart Pen Light Guide Member for Code Pattern Detection

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Solution Overview

Problem

Existing display devices with touch sensor elements face challenges in precisely sensing the location of a stylus/pen due to limitations in light guidance and reflection within the pen tip, which affects the accuracy of code pattern detection and coordinate data generation.

Innovation Solution

A smart pen is designed with a pen tip portion that includes a light emitting portion and a light guide member, forming a path for infrared light to be emitted and reflected from a display panel, allowing for precise detection of code patterns and generation of coordinate data through a code processor.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a simple pen tip structure is used, then device complexity is reduced, but light receiving efficiency and detection precision deteriorate

Engineering Contradiction:
Improvepen tip structureVSAvoidcode pattern detection precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The pen tip is divided into multiple functional segments: a light emitting portion, a light guide member with specific optical paths, and a pen tip portion with reflective surfaces. This segmentation allows each component to be optimized for its specific function while maintaining overall system precision without excessive complexity.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A light guide member is introduced as an intermediary component between the light emitting portion and the pen tip portion. This light guide member directs and focuses light along specific paths, enhancing light receiving efficiency at the reflective surfaces without requiring a more complex overall structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If light guiding components are added to the pen tip, then light receiving efficiency is improved, but device complexity increases

Engineering Contradiction:
Improvelight receiving efficiencyVSAvoidpen tip structure
Core Design Contradiction:
Illumination intensityVSDevice complexity

Solution Approach 1:

The light guide member incorporates curved surfaces and rounded transitions to direct light efficiently. The reflective surfaces at the pen tip portion are designed with specific curvatures to focus and redirect light, enhancing receiving efficiency through geometric optimization rather than adding complex components.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The light guide member and pen tip portion utilize optical properties such as reflectivity and light transmission to control light paths. By strategically placing reflective surfaces and transparent portions, the system enhances light receiving efficiency through optical property optimization rather than structural complexity.

Inventive Principle:
Principle #32Color changes

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

The smart pen effectively enhances light receiving efficiency and precision in detecting code patterns on a display panel, enabling accurate coordinate data transmission to a main processor, thereby improving the overall touch input experience.

Implementation Method 1

a light guide member forming a path for the light emitted from the light emitting portion to emit the light from the pen tip portion

Methodology Applied
Scientific EffectLight guidance: Optical Fibre

Implementation Method 2

receiving light reflected from a reflective surface of the pen tip portion and the display panel

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4177716B1Smart pen and display device using the same
Publication Date: 2025.03.05 SAMSUNG DISPLAY CO LTD
  • EP4177716B1 patent drawingFigure 1
  • EP4177716B1 patent drawingFigure 2
  • EP4177716B1 patent drawingFigure 3

AI summary

The present invention relates to a smart pen (20) and a display device (10) using the same, in which a reflective light reception rate may be enhanced through a light output structure to increase a code pattern (CP) and code information recognition rate of a display panel (100). According to an embodiment of the invention, the smart pen (20) comprises a body portion (26), a pen tip portion (27) formed on one end of the body portion (26) to form a path of light emitted from a light emitting portion (21(a)) in an end direction at one side, a code detector (21) detecting shape data for code patterns (CP) by applying light to the pen tip portion (27) and receiving light reflected from the display panel (100) and the pen tip portion (27), and a code processor (23) generating coordinate data by using the shape data and transmitting the coordinate data to a main processor (500) for driving the display panel (100).