OLED In-Cell OPD Structure for Lower Charge Extraction Barriers

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Solution Overview

Problem

Existing OLED displays face challenges in integrating organic photodetectors (OPDs) effectively, leading to inefficient charge extraction and signal-to-noise ratio due to energetic barriers between materials, which affects the performance of in-cell optical sensing applications.

Innovation Solution

The integration of OPDs into OLED displays is achieved by sharing structures like the cathode, hole transport layer, and electron transport layer with OLED pixels, and optimizing the placement and doping of electron donor and acceptor materials to form p-n junctions and energetic staircases, reducing hole and electron barriers for improved charge extraction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If OPDs are integrated into OLED displays by sharing structures, then device complexity is reduced, but charge extraction efficiency deteriorates due to energetic barriers between materials

Engineering Contradiction:

Improvestructure integrationVSAvoidcharge extraction efficiency

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces intermediate materials at the interfaces between the electron transport layer and electron acceptor material, and between the hole transport layer and electron donor material. These intermediaries act as mediators to reduce energetic barriers and facilitate efficient charge extraction, resolving the contradiction between structure sharing and charge extraction efficiency.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent modifies the energy level parameters of the transport layers and interface materials to create favorable energy alignments. By changing the energetic parameters (HOMO/LUMO levels) of the materials, the patent reduces charge extraction barriers while maintaining the shared structure between OLED and OPD pixels.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If electron donor and acceptor materials are optimized to form p-n junctions, then signal-to-noise ratio is improved, but manufacturing complexity increases

Engineering Contradiction:

Improvesignal-to-noise ratioVSAvoidmanufacturing process

Core Design Contradiction:

Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent combines the formation of p-n junctions with the existing OLED pixel structure. The electron donor and acceptor materials are integrated into the same device stack as the OLED components, merging the photodetector functionality with the display structure. This approach improves signal-to-noise ratio through proper junction formation while avoiding the need for completely separate manufacturing processes.

Inventive Principle:

Principle #5Merging (Combining)

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 approach enhances the efficiency of OPD pixels within OLED displays, improving the signal-to-noise ratio and overall performance of in-cell optical sensing applications by minimizing energetic barriers and optimizing material interactions.

Implementation Method 1

an electron donor material positioned between the OLED HTL and the OLED ETL, an electron acceptor material positioned between the OLED HTL and the OLED ETL, and a first interface between the electron acceptor material and the OLED ETL. The electron donor material including the p-dopant material and the electron acceptor material including the n-dopant material may form a p-n junction

Methodology Applied

Scientific EffectPhotovoltaic Effect: Photovoltaic Effect

Implementation Method 2

OPDs may be configured to sense visible light, infrared light, or other ranges of electromagnetic radiation wavelengths

Methodology Applied

Scientific EffectAbsorption (EM radiation): Absorption (EM radiation)

Data Source

PatentUS11839133B2Organic photodetectors for in-cell optical sensing

Publication Date: 2023.12.05 APPLE INC

AI summary

An organic light-emitting diode (OLED) display includes an array of OLED pixels and an array of organic photodetector (OPD) pixels. An OLED pixel in the array of OLED pixels includes an OLED hole transport layer (HTL), an OLED electron transport layer (ETL), and an emissive layer positioned between the OLED HTL and the OLED ETL. An OPD pixel in the array of OPD pixels includes the OLED HTL, the OLED ETL, and an electron donor material positioned between the OLED HTL and the OLED ETL, wherein the OLED ETL functions as an electron acceptor material for the OPD pixel. In other embodiments, the OPD pixel may be configured differently.