Staggered OLED Pixel Light Guiding Medium Structure

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Solution Overview

Problem

OLED displays face contrast issues due to ambient light reflection by the reflective electrode, which affects the visibility of pixel units not emitting light, leading to reduced display quality.

Innovation Solution

A display panel design featuring pixel units with a reflective electrode, a light emitting unit, and a color resist of the same color, where the geometric centers are staggered, and a light guiding medium structure with a refractive index difference between adjacent structures, filters ambient light by overlapping color resists of different colors, preventing reflection and enhancing contrast.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of stationary object

If a reflective electrode is used in the pixel unit to reflect ambient light, then the display can be made thinner and lighter, but the reflected ambient light causes reduced contrast and affects display quality

Engineering Contradiction:

Improvedisplay panel weightVSAvoidambient light reflection

Core Design Contradiction:

Weight of stationary objectVSObject-affected harmful factors

Solution Approach 1:

A light guiding medium structure is introduced as an intermediary component between the light emitting unit and the color resist. This structure includes a light guiding medium with refractive index n1 and a filler with refractive index n2 (where n1 > n2), creating an optical interface that redirects reflected ambient light away from the color resist, thereby eliminating the harmful reflection effect while preserving the reflective electrode's functionality

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent utilizes refractive index parameter differences between the light guiding medium (n1) and the filler (n2) to control light propagation. By carefully selecting materials with specific refractive index values and arranging them in alternating layers, the structure creates optical total internal reflection that redirects ambient light, transforming the optical parameters to achieve the desired contrast improvement

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the light emitting unit and color resist are positioned with non-overlapping geometric centers, then light can be effectively guided through the light guiding medium structure, but the structural complexity increases

Engineering Contradiction:

Improvelight guidance efficiencyVSAvoidpixel unit structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The pixel unit structure is segmented into distinct functional layers: the light emitting unit, the light guiding medium structure (with alternating high and low refractive index layers), and the color resist. This segmentation allows each component to perform its specific function optimally while maintaining a systematic arrangement that manages complexity through modular design

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The light guiding medium structure extends in the vertical dimension with multiple alternating layers of different refractive indices. This multi-layer vertical arrangement creates a three-dimensional optical path that guides light effectively from the light emitting unit through the color resist, transforming a two-dimensional planar problem into a three-dimensional solution that manages light propagation more efficiently

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 solution effectively filters ambient light, improving the contrast and brightness of the display panel by ensuring that light emitted from the light guiding medium structure passes through the color resist without affecting normal display operations, thus enhancing the overall display quality.

Implementation Method 1

a light guiding medium structure disposed between the light emitting unit and the color resist, a gap between adjacent light guiding medium structures, and a refractive index of a filler in the gap smaller than that of the light guiding medium structure

Methodology Applied

Scientific EffectRefraction: Refraction

Implementation Method 2

Methodology Applied

Scientific EffectTotal internal reflection: Total Internal Reflection

Implementation Method 3

When ambient light is applied to the display panel, the ambient tight is filtered by color resists of two different colors, so that the ambient light cannot be emitted outside the display panel

Methodology Applied

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

Data Source

PatentUS10873055B2Display panel having light guiding medium structure and display device

Publication Date: 2020.12.22 SHANGHAI TIANMA MICRO ELECTRONICS CO LTD

AI summary

Provided are a display panel and a display device. The display panel includes: a substrate and pixel units provided on the substrate, and the pixel units of at least two different colors are adjacently arranged. In a direction facing away from the substrate, one of the pixel units includes a reflective electrode, a light emitting unit and a color resist, and the light emitting unit and the color resist disposed in a same pixel unit have a same color, a vertical projection of a geometric center of the light emitting unit on the substrate is not overlapped with that of a geometric center of the color resist in the same pixel unit on the substrate. A vertical projection of the color resist in the pixel unit on the substrate is overlapped with that of the light emitting unit in a pixel unit closest to the pixel unit on the substrate.