Polarization Converter for Stereoscopic Projectors
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Solution Overview
Problem
Conventional projector systems using solid-state light sources face issues with brightness, UV emission, and high costs, particularly in stereoscopic displays which require active glasses and suffer from image cross-talk due to incomplete polarization filtering.
Innovation Solution
A polarization converter comprising a polarizing beam splitter, half wavelength retarder, and quarter wavelength retarder is used to convert light into circularly polarized beams, improving optical efficiency and enabling the use of passive glasses in a projector apparatus with reduced complexity and cost.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a rotary optical filtering wheel is used to perform beam splitting on stereoscopic images, then the system can provide split images of different wavelength regions to left and right eyes, but it is difficult to rotate in optimal synchronism with the color filter and increases device complexity
Solution Approach 1:
The patent extracts and removes the rotary optical filtering wheel from the system, replacing it with a polarization converter that uses fixed optical elements (polarizing beam splitter, half-wave retarder, quarter-wave retarder) to achieve beam splitting without rotational movement, thereby eliminating synchronization issues and reducing mechanical complexity
Solution Approach 2:
The patent replaces the mechanical rotary optical filtering wheel with an optical polarization-based system. The beam splitting function previously achieved through mechanical rotation is now accomplished through optical polarization conversion and beam splitting, eliminating the need for mechanical synchronization mechanisms
2Ease of operation
If active glasses with left and right shutter switching technology are used, then stereoscopic display can be achieved, but the brightness of left-eye and right-eye view-angle images decreases during operation
Solution Approach 1:
The patent extracts and removes the active glasses with shutter switching mechanism from the system. Instead, it uses a polarization converter to generate circularly polarized light that can be viewed with passive polarized glasses, eliminating the brightness loss associated with active shutter switching while maintaining stereoscopic display capability
Solution Approach 2:
The patent replaces expensive active glasses with inexpensive passive polarized glasses. The passive glasses have no moving parts or power requirements, eliminating the brightness loss from shutter switching while providing adequate stereoscopic viewing functionality
3Ease of operation
If conventional polarized light technology with S or P polarized direction is used, then stereoscopic display can be achieved, but image cross-talk occurs when user's head tilts due to incomplete sheltering
Solution Approach 1:
The patent changes the polarization parameter from linear polarization (S or P direction) to circular polarization. By using a polarization converter with half-wave and quarter-wave retarders, the system generates circularly polarized light for left and right eyes, which maintains effective image separation even when the user's head tilts, eliminating cross-talk issues
Solution Approach 2:
The patent uses a composite optical system combining polarizing beam splitter, half-wave retarder, and quarter-wave retarder to create a polarization converter. This composite structure transforms linearly polarized light into circularly polarized light, providing superior performance in preventing image cross-talk during head movement
4Duration of action of stationary object
If solid-state light sources such as LEDs or LDs are used, then the system has long service life, small volume and is free of mercury, but the brightness is considerably lower than conventional high-pressure mercury lamps
Solution Approach 1:
The patent addresses the brightness limitation of solid-state light sources by optimizing the optical system efficiency. By using a polarization converter that efficiently manages light paths and minimizes losses, the system maximizes the utilization of light from solid-state sources, converting the potential harm of limited brightness into acceptable performance through improved optical efficiency
Solution Approach 2:
The patent changes the polarization state of light through the converter system, enabling more efficient light utilization. The conversion to circular polarization and optimized beam splitting improves overall optical efficiency, allowing solid-state light sources to achieve sufficient brightness for practical applications
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 enhances brightness by minimizing brightness loss and eliminates image cross-talk, allowing for a cost-effective, miniaturized, and efficient stereoscopic projection system using passive glasses.
Implementation Method 1
The polarizing beam splitter splits a first light into a first light beam having a first polarized direction and a second light beam having a second polarized direction
Implementation Method 2
The half wavelength retarder is disposed on a side of the polarizing beam splitter for receiving the first light beam and the second light beam, the second light beam is converted into the second light beam having the first polarized direction by the half wavelength retarder
Implementation Method 3
The quarter wavelength retarder is disposed behind the half wavelength retarder for receiving the first polarized light and converting the first polarized light into a first circularly polarized light
Data Source
AI summary
A polarization converter for use in a projector apparatus is provided. The polarization converter includes a polarizing beam splitter, a half wavelength retarder and a quarter wavelength retarder. The polarizing beam splitter could split a first light into a first light beam with a first polarized direction and a second light beam with a second polarized direction. The half wavelength retarder is disposed on the side of the polarizing beam splitter and the second light beam is converted into the second light beam with the first polarized direction by the half wavelength retarder. The first and second light beams with the first polarized direction are coupled to form a first polarized light with the first polarized direction. The quarter wavelength retarder is disposed behind the half wavelength retarder so that the first polarized light is converted into a first circularly polarized light.