Projector Polarization Recycling for Light Energy Efficiency
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Solution Overview
Problem
In projectors with liquid crystal panels, about half of the light energy is lost when unpolarized light is converted to linear polarized light, and existing polarization conversion systems are inefficient in utilizing all available light energy, leading to suboptimal brightness and contrast ratios.
Innovation Solution
A projector design that incorporates a polarization conversion system, a reflective polarizer, and a lens array to recycle and convert previously unused polarized light, using a reflective polarizer to reflect and re-convert P-polarized light back into S-polarized light, enhancing the light conversion efficiency without increasing the light source power or optical engine volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If unpolarized light is converted to linear polarized light for liquid crystal panel utilization, then the liquid crystal panel can process the light, but about half of the light energy is lost
Solution Approach 1:
The patent recovers the P-polarized light that would otherwise be discarded by the reflective polarizer, redirecting it back through the polarization conversion system to be converted into S-polarized light that can be utilized by the liquid crystal panel, thereby recovering approximately 50% of the light energy that would otherwise be lost
Solution Approach 2:
The patent creates a continuous light recycling loop where P-polarized light is continuously reflected back through the polarization conversion system and converted to S-polarized light, maintaining continuous useful action on the light energy rather than allowing it to be lost after a single conversion attempt
2Productivity
If a polarization conversion system is used to convert more unpolarized light into linear polarized light, then more light can be utilized by the liquid crystal panel, but some light energy still cannot be converted
Solution Approach 1:
The patent implements a feedback mechanism where the reflective polarizer redirects unconverted P-polarized light back to the polarization conversion system, creating a closed-loop system that continuously attempts to convert the light until it becomes S-polarized and can pass through, significantly improving overall conversion efficiency
Solution Approach 2:
The system maintains continuous useful action on all light energy by repeatedly cycling the P-polarized light through the polarization conversion system, ensuring that no light energy is wasted after a single conversion attempt
3Illumination intensity
If the light source power is increased to compensate for light energy loss, then brightness can be maintained, but the output power of the light source increases
Solution Approach 1:
By recovering and recycling the P-polarized light that would otherwise be lost, the system maintains higher brightness output from the same light source power, eliminating the need to increase light source power to compensate for energy losses
4Illumination intensity
If more light sources are used to compensate for energy loss, then brightness can be maintained, but the quantity of light sources increases
Solution Approach 1:
The system recycles light from existing sources rather than requiring additional light sources, maintaining brightness with the same quantity of light sources by improving the utilization efficiency of the light they produce
5Productivity
If the optical engine volume is increased to accommodate more polarization conversion components, then light conversion efficiency can be improved, but the volume of the optical engine increases
Solution Approach 1:
The reflective polarizer serves multiple functions: it acts as a polarizing element for the liquid crystal panel, a beam splitter to separate S and P polarized light, and a mirror to redirect P-polarized light back through the system, eliminating the need for separate components and reducing overall volume
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
This approach significantly improves the polarized light conversion efficiency, enhancing the projector's brightness and contrast ratio by recycling and re-converting previously unused light energy, thereby improving overall system performance.
Implementation Method 1
The first P-polarized light P105 continues to pass through the retarder 103, wherein the most part of it is converted to the second S-polarized light S106
Implementation Method 2
The reflective polarizer allows the first S-polarized light and the second S-polarized light to pass through and reflects the first P-polarized light back to the polarization conversion system
Data Source
AI summary
A projector includes a polarization conversion system and a reflective polarizer. The polarization conversion system receives unpolarized light including first S-polarized light and first P-polarized light, wherein the first S-polarized light passes through the polarization conversion system, a part of the first P-polarized light is converted into second S-polarized light after passing through the polarization conversion system, and another part of the first P-polarized light remains unchanged after passing through the polarization conversion system. The reflective polarizer allows the first S-polarized light and the second S-polarized light to pass through and reflects the first P-polarized light back to the polarization conversion system.