Microlens-Capped 3D LED Structure for Directional Pixel Emission

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Solution Overview

Problem

The challenge lies in enhancing the luminous efficiency and directional focus of light emitted by three-dimensional light-emitting diodes, particularly as they miniaturize, while preventing light mixing between adjacent pixels in display screens and image projection systems, which results in decreased light intensity and efficiency due to non-directional emission and radiation loss.

Innovation Solution

An optoelectronic device featuring a three-dimensional light-emitting diode with a micrometric or nanometric optical lens made from a material with an optical index between 1.4 and 2.2, where the lens is in mechanical contact or close proximity to the diode, and an encapsulation material with a reflective wall to direct light rays, increasing the light intensity and efficiency by focusing and collimating the emitted light.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If three-dimensional light-emitting diodes are miniaturized to micrometric or nanometric dimensions, then the definition and resolution of display screens increases, but the light intensity emitted by the diodes decreases drastically

Engineering Contradiction:
Improvescreen definitionVSAvoidlight intensity
Core Design Contradiction:
Measurement precisionVSIllumination intensity

Solution Approach 1:

A micrometric or nanometric optical lens is formed above the light-emitting diode before light emission, pre-positioned to focus and collimate the emitted light rays. This preliminary optical structure ensures that even miniaturized LEDs can direct their light effectively, resolving the contradiction between small size and light intensity by preparing the optical path in advance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent introduces a vertical dimension by forming the optical lens above the LED along its longitudinal axis, transforming the light emission from a planar to a three-dimensional focused beam. This dimensional approach allows miniaturized LEDs to maintain high light intensity by concentrating emission in the vertical direction rather than spreading it laterally.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Device complexity

If three-dimensional light-emitting diodes are used, then the device structure is simplified, but the light emitted is not directional resulting in significant radiation loss

Engineering Contradiction:
Improvedevice structureVSAvoidradiation loss
Core Design Contradiction:
Device complexityVSLoss of energy

Solution Approach 1:

The optical lens is formed with a convex external surface that is spherical or aspherical, allowing it to effectively focus and collimate light rays emitted by the three-dimensional LED. This curved surface geometry transforms the omnidirectional emission into a directional beam, reducing radiation loss while maintaining the simplicity of the LED structure.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The optical lens acts as an intermediary element between the light-emitting diode and the external environment. It mediates the light emission by focusing and collimating the rays, converting the non-directional LED output into a directional beam without requiring modification to the LED structure itself.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If light containment walls are formed to block light radiation between adjacent diodes, then light mixing between pixels is prevented, but light radiation is partially absorbed causing luminous efficiency to fall

Engineering Contradiction:
Improvepixel separationVSAvoidluminous efficiency
Core Design Contradiction:
Measurement precisionVSLoss of energy

Solution Approach 1:

The patent extracts the light containment function from the traditional wall structure and relocates it to the optical lens. The lens, positioned above the LED, focuses and directs light rays upward and outward, naturally preventing lateral light mixing between adjacent pixels without requiring physical barriers that would absorb light. This extraction of the containment function eliminates the trade-off between pixel separation and luminous efficiency.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enhances the luminous efficiency and directional focus of light-emitting diodes, improving the overall performance by minimizing light loss and enhancing light extraction, thereby increasing the intensity and directionality of emitted light.

Implementation Method 1

an optical lens (14) formed above a distal portion (11a) of the light-emitting diode along a longitudinal axis (11b) of the light-emitting diode, the optical lens being capable of transforming light rays (L) emitted by the light-emitting diode

Methodology Applied
Scientific EffectRefraction: Refraction

Implementation Method 2

to focus or make the light rays emitted by a three-dimensional light-emitting diode as directional as possible

Methodology Applied
Scientific EffectFocusing: Focusing

Implementation Method 3

an encapsulation material with a reflective wall to direct light rays

Methodology Applied
Scientific EffectReflection: Reflection

Data Source

PatentEP3903354B1Optoelectronic device with a micrometrical or nanometrical light-emitting diode surmounted by an optical lens
Publication Date: 2024.06.12 ALEDIA INC
  • EP3903354B1 patent drawingFigure 1~2
  • EP3903354B1 patent drawingFigure 3~4
  • EP3903354B1 patent drawingFigure 5~6

AI summary

An optoelectronic device (10) comprises at least one light-emitting diode (11) having a three-dimensional shape having a height along a longitudinal axis (11b) and having a first longitudinal dimension (112) measured along the longitudinal axis (11b) and at least a second transverse dimension (113) corresponding to a dimension of the three-dimensional shape measured perpendicular to the longitudinal axis (11b). The first longitudinal dimension (112) and the second transverse dimension (113) are each less than or equal to substantially 20 µm. The optoelectronic device (10) comprises at least one optical lens (14) capable of transforming the light rays emitted by the light-emitting diode (11) which pass through the optical lens (14).