Display Touch Sensing With Pixel-Defined Position Code Patterns

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Solution Overview

Problem

Existing display devices face challenges in accurately determining input coordinates without complex calculations and corrections, leading to increased cost and power consumption during input operations using input devices.

Innovation Solution

A display device with a pixel defining layer that absorbs specific wavelengths of light and a touch electrode that reflects these wavelengths, combined with a code pattern for position information, allowing for direct generation of input coordinate data without complicated calculations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If code patterns are added to the display device, then input coordinate accuracy is improved, but device complexity increases

Engineering Contradiction:
Improveinput coordinate accuracyVSAvoiddevice complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent merges the code pattern function with the existing pixel defining layer structure. The pixel defining layer simultaneously serves as both the structural boundary for light emission and as the carrier for the code pattern, eliminating the need for separate code pattern components and reducing overall device complexity while maintaining input coordinate accuracy.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The pixel defining layer is given multiple functions: it defines the emission area boundaries, provides structural support for the light emitting element, and encodes position information through code patterns. This multi-functionality reduces the number of separate components needed, thereby reducing device complexity while improving measurement precision.

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

2Measurement precision

If the pixel defining layer absorbs specific wavelengths of light, then code pattern recognition accuracy is improved, but light emission quality may deteriorate

Engineering Contradiction:
Improvecode pattern recognition accuracyVSAvoidlight emission quality
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

The patent applies different optical properties to different regions of the pixel defining layer. The code pattern regions absorb specific wavelengths (e.g., infrared) for recognition, while the light emission regions maintain high light transmission and emission quality. This localized differentiation allows simultaneous optimization of both recognition accuracy and light emission performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The pixel defining layer uses wavelength-selective absorption characteristics to distinguish code patterns from emission areas. By changing the optical parameter (wavelength absorption) rather than altering the structural geometry, the system achieves accurate code recognition without compromising the overall light emission quality of the display device.

Inventive Principle:
Principle #35Parameter 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

Enables accurate input coordinate detection with reduced computational complexity and power consumption, simplifying the driving process and enhancing input precision.

Implementation Method 1

the pixel defining layer absorbs light of a specific wavelength

Methodology Applied
Scientific EffectLight absorption: Absorption (EM radiation)

Implementation Method 2

the pixel electrode and the touch electrode reflect the light of the specific wavelength

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP4134794B1Display device and sensing system including the same
Publication Date: 2026.02.11 SAMSUNG DISPLAY CO LTD
  • EP4134794B1 patent drawingFigure 1
  • EP4134794B1 patent drawingFigure 2
  • EP4134794B1 patent drawingFigure 3

AI summary

A display device (10) includes a thin-film transistor layer (TFTL) disposed on a substrate (SUB), the thin-film transistor layer (TFTL) including a thin-film transistor (TFT), a light emitting element layer (EML) disposed on the thin-film transistor layer (TFTL), the light emitting element layer (EML) including a pixel defining layer (PDL) defining emission areas (E1, E2, E3), and a pixel electrode (AND) disposed in each of the emission areas (E1, E2, E3), a touch electrode (SEN) disposed on the light emitting element layer (EML), the touch electrode (SEN) overlapping the pixel defining layer (PDL) and sensing a touch, and a code pattern (CP) defined by a planar shape of the pixel defining layer (PDL) that is distinguished from the pixel electrode (AND) and the touch electrode (SEN), the code pattern (CP) having position information.