Microlens Array Diffractive Lens Pitch Variation Light Focusing
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Solution Overview
Problem
Existing lighting systems using LEDs or lasers face inefficiencies in focusing white light from phosphors, with significant light loss due to misalignment of collimator and condenser lenses, and inadequate focusing capabilities even with condenser lenses present.
Innovation Solution
An optical member comprising a microlens array with a diffractive lens array is used, where the pitch of diffractive lenses varies across sections to effectively focus both blue and yellow light emitted by the phosphor, eliminating the need for a projector lens and minimizing light loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a collimator lens and condenser lens are used to control white light from phosphor, then light direction control is improved, but light loss increases due to misalignment and large emission angles
Solution Approach 1:
The patent divides the optical system into multiple microlenses arranged in an array, where each microlens independently processes a portion of the light from the phosphor. This segmentation allows each microlens to focus light precisely without requiring perfect alignment between large lenses, thereby reducing light loss while maintaining directional control.
Solution Approach 2:
Each microlens in the array is designed with specific local optical properties tailored to its position and the incident light characteristics from the phosphor. This local optimization ensures that each microlens efficiently processes its portion of the light, improving overall light utilization and reducing losses associated with global alignment requirements.
2Illumination intensity
If a condenser lens is added to improve focusing capability, then light focusing is enhanced, but device complexity and alignment requirements increase
Solution Approach 1:
The patent combines the functions of multiple microlenses into a single integrated array structure that performs both collimation and condensation functions simultaneously. This merging eliminates the need for separate collimator and condenser lenses, reducing device complexity while maintaining focusing capability through the collective action of the microlens array.
Solution Approach 2:
The patent transitions from using a small number of large lenses in a sequential arrangement to using a two-dimensional array of microlenses. This dimensional change allows parallel processing of light across the array, achieving the same focusing effect with reduced complexity and fewer alignment requirements.
3Productivity
If microlens array with varying pitch is used to focus light, then focusing efficiency is improved, but manufacturing precision requirements increase
Solution Approach 1:
The microlens array is designed with locally optimized pitch values that vary across different regions of the array. Each microlens has a pitch specifically tailored to its position and the incident light characteristics, maximizing focusing efficiency for each local region. This local quality approach allows the system to achieve high overall focusing efficiency while the pitch variation follows a predictable pattern that can be managed during manufacturing.
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 optical member enhances light focusing efficiency and reduces losses associated with lens misalignment, achieving higher diffraction efficiency and improved light transmission without requiring additional focusing components.
Implementation Method 1
an optical member according to claim 1
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
An optical member (10) includes: a phosphor layer (11) including a phosphor that converts a wavelength of a portion of light from a light source (16) which is incident on an incidence face; and a microlens array (12) that causes the portion of light wavelength-converted by the phosphor layer (11) and the other portion of light transmitted through the phosphor layer (11) to emerge from an emission face, in which a diffractive lens array (14) for diffracting the portion of light wavelength-converted and the other portion of light transmitted is provided on the emission face of the microlens array (12), and a pitch of the diffractive lens array (14) is different for each of predetermined sections.