Microlens Array Air Gap Structure for LED Light Collimation

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Solution Overview

Problem

Existing LED and pcLED technologies lack effective methods for collimating or partially collimating light output, which is necessary for improved directional light distribution in applications such as automotive adaptive headlights, augmented-reality displays, and camera flashes.

Innovation Solution

The integration of a microlens array with a spacer creating an air or low-refraction gap between the microlens array and the LEDs or pcLEDs, enhancing light collimation by utilizing the refractive index difference to focus light more effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Illumination intensity

If LEDs or pcLEDs are used without collimation, then the device structure is simple, but the light output lacks directionality

Engineering Contradiction:

Improvedirectional light outputVSAvoidoptical system structure

Core Design Contradiction:

Illumination intensityVSDevice complexity

Solution Approach 1:

The optical system is segmented into multiple microlenses arranged in an array, where each microlens independently collimates light from a corresponding LED or pcLED. This segmentation allows the system to achieve directional light output while maintaining a relatively simple overall structure, as each microlens element is identical and can be manufactured using standard techniques.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

An air gap is introduced as an intermediary between the microlens array and the LED or pcLED. This air gap serves as an optical intermediary that exploits the refractive index difference between air and the lens material to enhance light collimation. The air gap acts as a mediator that improves the optical interaction without adding mechanical complexity to the device structure.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Illumination intensity

If a microlens array is placed directly on the LED or pcLED, then the structure is compact, but light collimation is insufficient

Engineering Contradiction:

Improvelight collimationVSAvoiddistance between microlens array and LED

Core Design Contradiction:

Illumination intensityVSLength of stationary object

Solution Approach 1:

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The refractive index parameter is changed by introducing an air gap between the microlens array and the LED or pcLED. This parameter change exploits the optical property that light refraction is more effective when transitioning from a high refractive index material (lens) to a low refractive index medium (air), thereby enhancing the collimation effect without requiring a large physical distance.

Inventive Principle:

Principle #35Parameter changes

3Adaptability or versatility

If phosphor material is added to convert wavelengths, then the emission spectrum can be tailored, but the optical path becomes more complex

Engineering Contradiction:

Improveemission spectrum controlVSAvoidoptical path structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The microlens array and phosphor conversion elements are merged into a single integrated structure. The microlens array is positioned to work in conjunction with the phosphor layer, allowing both wavelength conversion and light collimation to occur within the same optical path. This merging eliminates the need for separate optical components, thereby achieving spectrum tailoring without proportionally increasing device complexity.

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

The microlens array with a spacer configuration improves light collimation, providing more directional light output and enhancing performance in various display and lighting applications.

Implementation Method 1

enhancing light collimation by utilizing the refractive index difference to focus light more effectively

Methodology Applied

Scientific EffectRefraction: Refraction

Data Source

PatentUS12572055B2Microlens array with built-in air gap

Publication Date: 2026.03.10 LUMILEDS SINGAPORE PTE LTD

AI summary

A microlens array comprises an array of microlenses on a flat base. A spacer located along the periphery of the microlens array protrudes away from the plane of the base. The microlens array may be arranged in combination with one or more LEDs or pcLEDs with the spacer positioned between the microlens array and the LEDs or pcLEDs and thus spacing the microlenses away from the LED or pcLEDs. Arranged in this manner, the surface of the microlens array facing the LEDs or pcLEDs and light emitting surfaces of the LEDs or pcLEDs together define an air filled or evacuated gap between the microlens array and the LEDs or pcLEDs, which improves the performance of the microlens array in collimating or partially collimating light emitted by the LEDs or pcLEDs.