Microlens Array Light Source Unit for Uniform Luminescence
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Solution Overview
Problem
Conventional projectors using laser emitters as excitation sources face issues with luminance saturation and failure due to scorching of luminescent materials, and inefficient utilization of light, leading to non-uniformity and reduced longevity.
Innovation Solution
A light source unit comprising an excitation light source, a microlens array that converts light into multiple pencils of light, and a collective lens to ensure uniform illumination of the luminescent material layer, preventing saturation and enhancing light utilization efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the power of the laser beam is increased to increase the quantity of luminescent light, then the luminescent light output is improved, but luminance saturation or failure due to scorching of the luminescent material is generated
Solution Approach 1:
The invention divides the single high-power laser beam into multiple lower-power light ray bundles using a microlens array. Each bundle illuminates a different region of the luminescent material layer, preventing concentration of energy on a single spot and thereby avoiding scorching and luminance saturation while maintaining high overall light output.
Solution Approach 2:
The invention applies different illumination characteristics to different regions of the luminescent material layer. By using multiple light ray bundles with controlled distribution, each region receives appropriate light intensity, ensuring uniform luminescence without localized overheating or saturation.
2Reliability
If the laser beam is diffused to weaken the power per unit area, then scorching is prevented, but the area illuminated exceeds the luminescent material layer area, decreasing light utilization efficiency
Solution Approach 1:
The laser beam is segmented into multiple light ray bundles that collectively cover the luminescent material layer area. This segmentation allows the light to be distributed across the entire active area without excessive diffusion, maintaining high light utilization efficiency while preventing scorching through reduced power density.
Solution Approach 2:
The invention transitions from a single-point high-intensity illumination to a multi-point distributed illumination pattern. By arranging multiple light ray bundles in a spatial configuration that matches the luminescent material layer geometry, the system achieves uniform coverage without wasting light beyond the active area.
3Productivity
If the laser beam is concentrated to increase power density, then excitation efficiency is improved, but luminance non-uniformity is generated
Solution Approach 1:
The concentrated laser energy is segmented into multiple light ray bundles that are distributed across the luminescent material layer. Each bundle maintains sufficient power density for effective excitation, while the overall distribution ensures uniform luminescence across the entire illuminated area.
Solution Approach 2:
The invention changes the spatial distribution parameter of the light beam from concentrated to distributed while maintaining appropriate power density in each region. By adjusting the number, size, and arrangement of light ray bundles, the system achieves both high excitation efficiency and uniform luminescence output.
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 enables uniform luminescence of the luminescent material, preventing scorching and luminance non-uniformity, resulting in stable and long-lasting projection with improved light utilization.
Implementation Method 1
a microlens array which is interposed between the excitation light source and the luminescent plate and which converts light emitted from the excitation light source into a plurality of pencils of light
Implementation Method 2
a luminescent plate including a luminescent material layer which becomes luminous by utilizing light emitted from the excitation light source as exciting light
Implementation Method 3
a collective lens which is disposed in proximity to the luminescent plate and which shines the plurality of pencils of light onto the luminescent plate so that center positions of the plurality of pencils of light are superposed one on another on the luminescent material layer
Data Source
AI summary
To provide a projector which enables a stable projection for a long period of time, there is provided a projector comprising a light source unit, a display device, a projection-side optical system, a light guiding optical system and a projector control unit, wherein the light source unit comprises an excitation light source unit comprising an excitation light source and a microlens array and a rectangular green luminescent plate which receives light emitted from the excitation light source to emit light in a green wavelength band, and the microlens array is disposed between the excitation light source and the luminescent plate and has a plurality of micro convex lenses which each have a similar shape to the shape of the luminescent material layer are arranged into a matrix, so as to convert light from excitation light source into a plurality of pencils of light to shine them onto the luminescent plate.