Single-Panel Projection Engine Polarization Recycling
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Solution Overview
Problem
Microdisplay projection systems using reflective LCOS imagers suffer from low optical efficiency due to the limited use of illumination light in one polarization state, resulting in reduced projection intensity on the screen.
Innovation Solution
An integrated single-panel projection engine is designed with a collimated light source, main and supporting polarization beam splitters, a reflective quarter wave plate, a mirror plate, and a projection lens system, which recycles the source polarization second-state beam to enhance optical efficiency by utilizing both polarization states for projection display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single LCOS imager and one PBS are employed in a single-imager engine, then the device complexity is reduced, but the optical efficiency deteriorates because only limited portion of illumination light in one polarization state is used
Solution Approach 1:
The patent recycles the polarization second-state beam that would otherwise be discarded by the PBS. The quarter wave plate converts this beam's polarization state, and the mirror plate redirects it back through the PBS to the LCOS imager, enabling reuse of previously wasted light energy and improving optical efficiency
Solution Approach 2:
The quarter wave plate and mirror plate act as intermediary components between the PBS and the LCOS imager. These intermediaries transform and redirect the polarization second-state beam, enabling it to reach the imager and be converted into useful projection light, thus resolving the efficiency loss
2Ease of operation
If a single LCOS imager and one PBS are employed in a single-imager engine, then the ease of operation is improved, but the projection intensity deteriorates due to limited illumination light utilization
Solution Approach 1:
The patent recycles the polarization second-state beam that would otherwise be discarded by the PBS. The quarter wave plate converts this beam's polarization state, and the mirror plate redirects it back through the PBS to the LCOS imager, enabling reuse of previously wasted light energy and improving optical efficiency
Solution Approach 2:
The patent establishes a continuous optical path where the polarization second-state beam is not terminated but continuously redirected back to the LCOS imager. This continuous recycling of light ensures maximum utilization of illumination light, maintaining high projection intensity
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 significantly improves optical efficiency by recycling and reusing the illumination light, allowing for a substantial increase in the amount of light projected onto the screen, thereby enhancing the display quality.
Implementation Method 1
the main polarization beam splitter configured in an angle α close to 45-degree with the first direction transmits the source polarization first-state beam while reflect light in second polarization state
Implementation Method 2
the reflective quarter wave plate configured in parallel to the first direction converts the second polarization second-state beam from second polarization state to first polarization state
Implementation Method 3
the mirror plate configured in parallel to the reflective quarter wave plate reflects the second polarization first-state beam back to the supporting polarization beam splitter
Data Source
AI summary
The present invention discloses an integrated single-panel projection engine (500) including a collimated light source (400), a main polarization beam splitter (200), a supporting polarization beam splitter (210), a reflective quarter wave plate (150), a mirror plate (160), an LCOS imager (100) and a projection lens system (300), which provides substantial improvement in optical efficiency of LCOS micro projection display.