Depolarizing Plate for Projection Display White Balance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional projection-type image display apparatuses using polarization for stereoscopic imaging face challenges in maintaining high image quality due to variations in polarization characteristics, leading to color imbalances and poor white balance, especially when using solid-state light sources like blue-color semiconductor lasers.
Innovation Solution
Incorporating a depolarizing plate with birefringent prisms, such as quartz, oriented at a 45-degree angle relative to the polarizing axis of the blue-color light, to depolarize light and maintain even polarization across the visible spectrum, thereby ensuring consistent image quality and white balance by complementing a polarizing plate on the output side of the projection optical system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polarizing plate is used in a projection-type image display apparatus with a blue-color semiconductor laser, then stereoscopic image projection is enabled, but color imbalances and poor white balance occur due to variations in polarization characteristics
Solution Approach 1:
A depolarizing plate is introduced as an intermediary component between the light source and the polarizing plate. This depolarizing plate converts the polarized blue-color laser light into unpolarized light, which then passes through the polarizing plate to create properly polarized projection light. This intermediary solution eliminates the color imbalance caused by direct polarization of blue laser light while maintaining stereoscopic image projection capability.
Solution Approach 2:
The invention changes the polarization state parameter of the light by introducing a depolarizing plate. The blue-color semiconductor laser emits polarized light, but the depolarizing plate converts it to unpolarized light before it reaches the polarizing plate. This parameter change ensures that the polarizing plate receives unpolarized light and outputs properly polarized light without color imbalance, resolving the contradiction between stereoscopic projection and color balance.
2Illumination intensity
If a blue-color semiconductor laser is used as the light source, then high brightness output is achieved, but polarization characteristic variations cause image quality degradation
Solution Approach 1:
The depolarizing plate serves as a mediator that decouples the high brightness advantage of the blue-color semiconductor laser from its harmful polarization characteristics. By converting the polarized laser light to unpolarized light, the system maintains the high brightness output while eliminating the polarization-induced image quality degradation.
Solution Approach 2:
The invention converts the harmful polarized light output from the blue-color semiconductor laser into beneficial unpolarized light. The depolarizing plate transforms the polarization characteristic variation from a harmful factor into a neutral state, allowing the high brightness output to be fully utilized without image quality degradation.
3Adaptability or versatility
If polarization is used for stereoscopic imaging, then right and left eye images can be separated, but color variations occur across the visible spectrum
Solution Approach 1:
The depolarizing plate acts as an intermediary that ensures uniform color transmission across the visible spectrum. By converting polarized light to unpolarized light before it enters the polarizing plate, the system achieves consistent polarization characteristics for all wavelengths, enabling stereoscopic imaging without color variations.
Solution Approach 2:
The invention applies the homogeneity principle by ensuring that all colors in the visible spectrum are treated equally regarding polarization. The depolarizing plate creates a uniform unpolarized light state that, when polarized by the polarizing plate, results in consistent polarization characteristics across all wavelengths, eliminating color variations while maintaining stereoscopic imaging capability.
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 use of a depolarizing plate enhances light utilization efficiency and image quality by ensuring that all colors are transmitted equally, reducing color variations and maintaining high image fidelity in stereoscopic projections.
Implementation Method 1
a fluorescent substance having characteristics of emitting predetermined fluorescence in response to excitation light
Implementation Method 2
The excitation optical system condenses the light from the excitation light source apparatus
Implementation Method 3
The projection optical system is an optical system capable of enlarging and projecting an image displayed by the image display element
Implementation Method 4
The polarizing plate is disposed on an output side of the projection optical system
Implementation Method 5
Incorporating a depolarizing plate with birefringent prisms, such as quartz, oriented at a 45-degree angle relative to the polarizing axis of the blue-color light, to depolarize light
Data Source
AI summary
A projection-type image display apparatus of the present disclosure includes a fluorescent substance, a blue-color laser diode excitation optical system, a DMD, a projection optical system, a polarizing plate, and a depolarizing plate. The fluorescent substance has characteristics of emitting predetermined fluorescence in response to excitation light. The blue-color laser diode has a semiconductor laser that emits laser light of a wavelength with which the fluorescent substance is excited. The excitation optical system condenses light from the blue-color laser diode. The DMD is controllable by a signal from an external source. The projection optical system is an optical system that can enlarge and project an image displayed by the DMD. The polarizing plate is disposed on the output side of the projection optical system.