Microlens-Tuned Light Emitting Elements for Uniform View Angle

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Solution Overview

Problem

Light emitting devices with optical resonance structures exhibit differences in view angle characteristics between pixels having different interference orders, leading to inconsistent performance.

Innovation Solution

A light emitting device comprising first and second light emitting elements with corresponding microlenses, where the relationship between the areas of light emission regions and incident regions satisfy specific conditions to minimize differences in view angle characteristics.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If light emitting elements with different interference orders are used, then light extraction efficiency is improved, but view angle characteristic uniformity deteriorates

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoidview angle characteristic uniformity
Core Design Contradiction:
Illumination intensityVSReliability

Solution Approach 1:

The patent applies local quality by making the microlens curvature radius specific to each light emitting element's interference order. Elements with different interference orders have microlenses with differently optimized curvature radii, allowing each element to achieve optimal light extraction efficiency for its specific interference order while maintaining uniform view angle characteristics across all elements.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent utilizes parameter changes by adjusting the curvature radius of microlenses based on the interference order of each light emitting element. By changing the curvature radius parameter according to the specific interference order, the patent optimizes light extraction efficiency for each element type while ensuring consistent view angle characteristics across the display.

Inventive Principle:
Principle #35Parameter changes

2Illumination intensity

If microlens curvature is increased to improve light extraction efficiency, then light emission in normal direction is enhanced, but view angle characteristic deteriorates

Engineering Contradiction:
Improvelight extraction efficiencyVSAvoidview angle characteristic
Core Design Contradiction:
Illumination intensityVSEase of operation

Solution Approach 1:

The patent applies local quality by optimizing the microlens curvature radius specifically for each light emitting element's interference order. This localized optimization ensures that each element achieves the best possible light extraction efficiency without compromising overall view angle characteristics, as each microlens is tailored to its specific element's optical properties.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent implements dynamics by having different curvature radii for microlenses corresponding to different interference orders. This dynamic adjustment of curvature radius based on interference order allows the system to adaptively optimize light extraction for each element type while maintaining uniform view angle characteristics across the entire display.

Inventive Principle:
Principle #15Dynamics

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 suppresses differences in view angle characteristics between pixels with varying interference orders, enhancing overall performance.

Implementation Method 1

Excitons of a luminous organic compound in the organic compound layer are generated by injecting electrons and holes from the pair of electrodes to the organic compound layer, and when the excitons return to a ground state, the organic light emitting element emits light

Methodology Applied
Scientific EffectElectroluminescence: Electroluminescence

Implementation Method 2

a first microlens and a second microlens arranged so as to correspond to the first light emitting element and the second light emitting element, respectively

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 3

In a light emitting element having an optical resonance structure, the light radiation distribution has more components in the front direction

Methodology Applied
Scientific EffectInterference: Interference

Data Source

PatentEP4648585A1Light emitting device, photoelectric conversion device, electronic apparatus, illumination device, and mobile body
Publication Date: 2025.11.12 CANON KK
  • EP4648585A1 patent drawingFigure 1
  • EP4648585A1 patent drawingFigure 2~3
  • EP4648585A1 patent drawingFigure 4

AI summary

A light emitting device comprises a first light emitting element and a second light emitting element formed on a substrate, and a first microlens and a second microlens. The first light emitting element includes a first light emitting layer, and an optical resonance structure having a first optical path length, and the second light emitting element includes a second light emitting layer, and an optical resonance structure having a second optical path length longer than the first optical path length. Assuming that an area of a region where light having entered from a normal direction of the substrate and having passed through the first microlens enters a light emission region of the first light emitting layer is defined as S1, an area of the light emission region of the first light emitting layer is defined as S1', an area of a region where light having entered from a normal direction of the substrate and having passed through the second microlens enters a light emission region of the second light emitting layer is defined as S2, and an area of the light emission region of the second light emitting layer is defined as S2', then |S1 - S1'| < |S2 - S2'|.