Photonic Crystal Light Source Module Polarization Separation
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Solution Overview
Problem
Photonic crystal light emitting elements with a rectangular resonant part shape face challenges in maintaining uniform light distribution angles, leading to difficulties in separating S-polarized and P-polarized light in liquid crystal projectors, which affects the polarization degree of the emitted light.
Innovation Solution
A light source module incorporating a photonic crystal light emitting element with a resonant part having a shorter length in one direction and a longer length in a perpendicular direction, combined with a polarization conversion element featuring a polarization split layer, reflecting layer, and retardation layer, ensures efficient separation and conversion of polarized light, enhancing the polarization degree of the emitted light.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the resonant part is given a rectangular shape with long sides in the X-axis direction and short sides in the Y-axis direction to improve heat dissipation, then the heat dissipation performance is improved, but the light distribution angle becomes different between directions and S-polarized light and P-polarized light cannot be correctly separated
Solution Approach 1:
The resonant part is designed with an asymmetric rectangular shape having different dimensions in the X-axis and Y-axis directions. This asymmetry creates different light distribution angles in different directions, which is then compensated by the polarization conversion element to achieve correct polarization separation while maintaining the heat dissipation benefits of the rectangular shape
Solution Approach 2:
The invention changes the polarization state parameters of light through the polarization conversion element (comprising polarization split layer, reflecting layer, and retardation layer). By converting between S-polarized and P-polarized light, the system compensates for the directional differences in light distribution angle caused by the rectangular resonant part shape, enabling correct polarization separation
2Loss of energy
If a rectangular shape is provided to the resonant part to increase the proportion of outer circumferential length per light emission area, then heat dissipation is improved, but the light distribution angle increases in certain directions affecting polarization separation
Solution Approach 1:
The polarization conversion element acts as an intermediary between the light source (rectangular resonant part) and the polarization beam splitter. It mediates the directional light distribution by converting polarization states, transforming the light in a form that can be correctly separated by the polarization beam splitter despite the asymmetric geometry of the resonant part
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 correct separation of S-polarized and P-polarized light, achieving high polarization efficiency and improved heat dissipation, while reducing the size and increasing the intensity of the light source module.
Implementation Method 1
Photonic crystal light emitting element resonates light in a resonant part of a resonator constituted by the photonic crystal structure
Implementation Method 2
The photonic crystal light emitting element is capable of emitting a laser beam
Implementation Method 3
a polarization split layer configured to reflect first polarized light out of incident light toward a first direction, and transmit second polarized light out of incident light toward a second direction perpendicular to the first direction
Implementation Method 4
a reflecting layer configured to reflect the first polarized light reflected by the polarization split layer, toward the second direction
Implementation Method 5
a retardation layer which is disposed in a light path of one of the first polarized light reflected by the reflecting layer and the second polarized light transmitted through the polarization split layer, and converts the one of the first polarized light and the second polarized light into another of the first polarized light and the second polarized light
Data Source
AI summary
A light source module includes a light emitting element having a resonator formed of a photonic crystal structure, and a polarization conversion element, wherein the polarization conversion element includes a polarization split layer that reflects first polarized light toward a first direction, and transmit second polarized light toward a second direction, a reflecting layer that reflects the first polarized light, toward the second direction, and a retardation layer which is disposed in a light path of one of the first polarized light and the second polarized light, and converts the one of the first polarized light and the second polarized light into another of the first polarized light and the second polarized light, the resonator has a resonant part, and in a plan view, a length of the resonant part in the first direction is shorter than a length of the resonant part in a third direction perpendicular to the first direction and the second direction.