Sub-Pixel Layout for Precise Fingerprint Sensing in Displays

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Solution Overview

Problem

Existing display devices struggle to precisely detect external inputs such as fingerprints due to limitations in the design of sub-pixels and light-sensing pixels, which affect the resolution and accuracy of input detection.

Innovation Solution

The display device is designed to secure the sectional area of a photo-sensing pixel by altering the shape of the emission and light-receiving areas of sub-pixels, allowing for precise detection of external inputs by changing the shape of the emission and light-receiving areas of sub-pixels and light-sensing pixels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If the emission area and light-receiving area shapes are changed to secure photo-sensing pixel sectional area, then input detection precision is improved, but device structure complexity increases

Engineering Contradiction:
Improveinput detection precisionVSAvoiddevice structure complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The pixel array is segmented into distinct sub-pixel regions (first, second, third sub-pixels) with different emission area configurations. Each sub-pixel type has specifically designed emission and light-receiving area shapes that work together to optimize photo-sensing performance while maintaining manageable structural complexity through modular design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the pixel array are assigned different local characteristics - specifically, the first sub-pixel has a different emission area shape compared to the second and third sub-pixels. This local differentiation optimizes light reception in specific areas while maintaining overall device functionality, resolving the contradiction between precision and complexity

Inventive Principle:
Principle #3Local quality

2Measurement precision

If the emission area shape of sub-pixel is altered to increase light reception, then photo-sensing accuracy is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvephoto-sensing accuracyVSAvoidmanufacturing precision requirements
Core Design Contradiction:
Measurement precisionVSManufacturing precision

Solution Approach 1:

The emission area of the first sub-pixel is designed with an asymmetric shape that differs from the emission areas of the second and third sub-pixels. This asymmetric design optimizes light reception paths for photo-sensing accuracy while the design is sufficiently simple to be manufactured with standard precision tolerances, avoiding excessive manufacturing complexity

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The emission and light-receiving areas are designed with curved boundaries rather than sharp angular shapes. This curvature approach smooths out manufacturing tolerances and makes the design more robust to fabrication variations, thereby improving photo-sensing accuracy without proportionally increasing manufacturing precision requirements

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

This design enables precise detection of external inputs, such as fingerprints, by enhancing the resolution and accuracy of input detection in display devices.

Implementation Method 1

a light-emitting element LD configured to emit light in response to application of a driving current

Methodology Applied
Scientific EffectLight emission: Light Emitting Diode

Implementation Method 2

a light-receiving element OPD configured to receive the light reflected from the fingerprint

Methodology Applied
Scientific EffectLight detection: Photoelectric Effect

Data Source

PatentEP4163770B1Display device
Publication Date: 2025.11.26 SAMSUNG DISPLAY CO LTD
  • EP4163770B1 patent drawingFigure 1
  • EP4163770B1 patent drawingFigure 2
  • EP4163770B1 patent drawingFigure 3

AI summary

A display device includes a substrate, and unit pixels provided in the substrate, and including sub-pixels each having a light-emitting element emitting light, and photo-sensing pixels each having a light-receiving element outputting a sensing signal corresponding to the light. Each of the sub-pixels may include an emission area emitting the light, and each of the photo-sensing pixels may include a light-receiving area receiving the light. The emission area and the light-receiving area may be provided in the substrate to be spaced apart from each other. Each of the emission area and the light-receiving area may have a shape of a quadrangular plane.