Light Source Device Polarization Conversion for Projection Displays
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Solution Overview
Problem
Existing light source devices for projection display apparatuses have limited light utilization efficiency, as they do not effectively manage the polarization and wavelength conversion of light, leading to inefficiencies in the generation and modulation of image light.
Innovation Solution
A light source device comprising a light source element, a first selective reflection element, a second selective reflection element, and a polarization direction conversion element that converts linear polarized light into elliptical polarized light, enhancing light utilization by optimizing the polarization and wavelength conversion processes, thereby improving the efficiency of light emission and modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional light source devices use simple linear polarized light transmission without polarization direction conversion, then the device structure is simple, but light utilization efficiency is limited
Solution Approach 1:
A quarter wave plate is introduced as an intermediary optical element between the light source and the optical modulator. This wave plate converts linear polarized light to circular polarized light, enabling the optical modulator to utilize both polarization components of light, thereby improving light utilization efficiency without significantly complicating the overall device structure
Solution Approach 2:
The patent changes the polarization state parameter of light from linear to circular by using a quarter wave plate. This parameter transformation allows the optical system to utilize both orthogonal polarization components of light, effectively doubling the usable light intensity and improving overall light utilization efficiency
2Illumination intensity
If the light source device uses wavelength conversion elements like phosphor wheels, then color light generation is improved, but light loss occurs during wavelength conversion
Solution Approach 1:
The patent ensures continuous utilization of light by converting linear polarized light to circular polarized light, which allows both polarization components to be continuously utilized through the optical modulator and wavelength conversion elements, minimizing light loss and maintaining continuous useful action throughout the optical path
3Power
If conventional systems use only linear polarized light, then the optical path is simple, but light intensity utilization is insufficient
Solution Approach 1:
A quarter wave plate is positioned as an intermediary element in the optical path to convert linear polarized light from the light source into circular polarized light. This enables the optical modulator to modulate both orthogonal polarization components, effectively doubling the utilized light intensity while adding only a single optical element to the system
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 proposed solution significantly enhances light utilization efficiency by reducing light loss and improving the conversion efficiency of light, resulting in improved luminance and image quality in projection display apparatuses.
Implementation Method 1
a first selective reflection element configured to transmit or reflect first linear polarized light and reflect or transmit second linear polarized light
Implementation Method 2
a first polarization direction conversion element configured to convert the first linear polarized light into elliptical polarized light
Implementation Method 3
a second selective reflection element configured to transmit or reflect the incident light in accordance with a wavelength region of the incident light
Implementation Method 4
a wavelength conversion element configured to convert light in a first wavelength region into second light in a second wavelength region
Data Source
AI summary
A light source device includes: a light source element emitting first light; a first selective reflection element disposed at a position where the first light is incident, the first selective reflection element transmitting a component of first linear polarized light and reflecting a component of second linear polarized light; a second selective reflection element disposed at a position for receiving incident light that has passed through or been reflected by the first selective reflection element, the second selective reflection element transmitting or reflecting the incident light in accordance with a wavelength region; and a first polarization direction conversion element disposed between the first and second selective reflection element, the first polarization direction conversion element converting the first linear polarized light into elliptical polarized light. The first polarization direction conversion element converts the elliptical polarized light reflected by the second selective reflection element into the second linear polarized light.