Display Readout Circuit for Thin Biometric Sensing Panels

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Solution Overview

Problem

Existing display devices struggle to accurately detect biometric information such as fingerprints and pulse using capacitive, optical, and ultrasonic schemes, often requiring separate input sensing layers which increase thickness and limit flexibility.

Innovation Solution

A display device incorporating a sensor with a readout circuit that includes a reference current conveyor and sensing circuit, utilizing current memory cells and analog-to-digital converters to accurately process sensing signals, allowing for biometric information detection without additional input sensing layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If separate input sensing layers are added to detect biometric information, then biometric detection capability is improved, but device thickness increases and flexibility deteriorates

Engineering Contradiction:

Improvebiometric detection capabilityVSAvoiddevice thickness

Core Design Contradiction:

Measurement precisionVSLength of stationary object

Solution Approach 1:

The patent merges the biometric sensing function with the existing display panel structure by utilizing the touch electrode and signal line layers that are already present in the display device. The sensing circuit is integrated into the same substrate as the display elements, eliminating the need for separate input sensing layers while maintaining biometric detection capability.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The existing touch panel layers and signal lines in the display device are made multi-functional by enabling them to perform both touch input detection and biometric information sensing. The same electrode structures used for touch control are utilized for fingerprint or pulse detection, allowing a single structure to serve multiple purposes.

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Measurement precision

If separate input sensing layers are added to detect biometric information, then biometric detection capability is improved, but device flexibility deteriorates

Engineering Contradiction:

Improvebiometric detection capabilityVSAvoiddevice flexibility

Core Design Contradiction:

Measurement precisionVSAdaptability or versatility

Solution Approach 1:

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs thin-film transistor (TFT) technology and flexible substrate materials to implement the sensing circuit, enabling the display device to maintain flexibility and adaptability for foldable or rollable applications while integrating biometric sensing functionality.

Inventive Principle:

Principle #30Flexible shells and thin films

3Measurement precision

If complex sensing circuits with multiple memory cells and converters are used, then sensing signal accuracy is improved, but circuit complexity increases

Engineering Contradiction:

Improvesensing signal accuracyVSAvoidcircuit complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent segments the sensing signal processing into distinct functional blocks: a sensing circuit for signal acquisition, current memory cells for signal storage and timing control, and analog-to-digital converters for signal conversion. This segmentation allows each block to be optimized independently while working together to achieve accurate biometric detection.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The current memory cells perform preliminary actions by storing the sensing signal at specific timing points and generating control signals in advance. This preliminary storage and timing control prepares the signal for accurate conversion and processing, improving measurement precision while organizing the circuit functionality in a structured manner.

Inventive Principle:

Principle #10Preliminary action

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 detection of biometric information like fingerprints and pulse while reducing device thickness, enhancing flexibility and enabling applications like foldable or rollable displays.

Implementation Method 1

an optical scheme for recognizing biometric information detects incident light by using an optical sensor

Methodology Applied

Scientific EffectPhotoelectric Effect: Photoelectric Effect

Data Source

PatentUS20260011174A1Readout circuit and display device including the same

Publication Date: 2026.01.08 SAMSUNG DISPLAY CO LTD

AI summary

A display device includes a display panel and a readout circuit. The display panel includes a pixel including a light emitting element, a sensor including a light sensing element, and a dummy sensor. The readout circuit outputs a readout signal based on a sensing signal received from the sensor and a dummy sensing signal received from the dummy sensor. The readout circuit includes a reference current conveyor that outputs a reference signal corresponding to the dummy sensing signal, and a sensing circuit that outputs the readout signal corresponding to a difference between the sensing signal and the reference signal.