Depolarizer Placement for Uniform Light Distribution in Projection Displays
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Solution Overview
Problem
Projectors using solid state light sources experience deviation in light quantity distribution due to polarization state disturbances and unbalanced energy distribution, leading to color unevenness in projected images.
Innovation Solution
A projection display apparatus with a light source unit, image light generator, projecting unit, and polarization modulator, where a depolarizer is placed on the optical path between the light emitting element and the polarization modulator to eliminate polarization, ensuring uniform light distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a solid state light source emitting polarized light is used, then the durability is improved and UV light degradation is prevented, but deviation in light quantity distribution occurs due to polarization state disturbance
Solution Approach 1:
A depolarizer is introduced as an intermediary component between the solid state light source and the subsequent optical system. This depolarizer converts the polarized light from the light source into non-polarized light, eliminating the polarization state disturbance that causes light quantity distribution deviation while preserving the benefits of the solid state light source
Solution Approach 2:
The polarization state of the light is changed from polarized to non-polarized by introducing a depolarizer. This parameter change in the light's physical state eliminates the harmful effects of polarization maintenance while retaining the advantages of the solid state light source
2Adaptability or versatility
If polarized light is used for stereoscopic display, then three-dimensional image recognition is enabled, but light quantity distribution deviation causes color unevenness
Solution Approach 1:
The optical system is segmented into distinct functional sections: a depolarizer section that processes the light source output, and a polarization modulator section that applies polarization for stereoscopic display. This segmentation allows independent optimization of each function, ensuring uniform light distribution while maintaining stereoscopic capability
Solution Approach 2:
The depolarizer performs a preliminary action by converting polarized light to non-polarized light before the light enters the polarization modulator. This preliminary depolarization prevents light quantity distribution deviation from occurring in the first place, while the subsequent polarization modulator can still apply the necessary polarization states for stereoscopic display
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
Prevents deviation in light quantity distribution, thereby eliminating color unevenness and enhancing image quality by ensuring consistent light intensity across the projected image.
Implementation Method 1
a depolarizer that is arranged on the optical path between the light emitting element and the polarization modulator
Implementation Method 2
a polarization modulator on which the image light is made incident and that emits light in a particular polarization state
Data Source
AI summary
A projection display apparatus that can prevent deviation in the light quantity distribution of the projected image is provided. A projection display apparatus includes: a light source unit including a light emitting element; an image light generator modulating light from the light source unit to emit image light; a projecting unit projecting the image light; a polarization modulator on which the image light is made incident and that emits light in a particular polarization state; and a depolarizer arranged on the optical path between the light emitting element and the polarization modulator.