Projection Light Source Module With Repeated Lens-Array Homogenization
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Solution Overview
Problem
The challenge in projection devices is to reduce volume and weight while maintaining uniform illumination, which requires addressing issues like minimizing light speckles and achieving consistent average light intensity.
Innovation Solution
A light source module design incorporating a polarizing beam splitter, lens array, quarter wave film, and reflector to convert and homogenize illumination beams, allowing them to pass through the same lens array repeatedly, reducing the need for multiple homogenization elements and optimizing the light path.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple homogenization elements are used to achieve uniform illumination, then light intensity uniformity is improved, but device volume and weight increase
Solution Approach 1:
The patent combines multiple functions (polarization separation, wave conversion, homogenization, and reflection) into a single integrated optical path. The illumination beam passes through the same lens array multiple times in sequence, with each pass contributing to homogenization. This merging of functions eliminates the need for multiple separate homogenization elements, achieving uniform light intensity while reducing device volume and weight by nearly 80% compared to conventional designs.
Solution Approach 2:
The illumination beam undergoes continuous homogenization by passing through the lens array in sequence multiple times. The polarizing beam splitter and quarter wave film enable the beam to traverse the same optical path repeatedly, with each traversal contributing to uniformity. This continuous action through a single integrated path achieves the homogenization effect of multiple elements without the associated volume penalty.
2Illumination intensity
If multiple homogenization elements are used to minimize light speckles, then illumination uniformity is improved, but device complexity increases
Solution Approach 1:
The patent merges polarization control, wave conversion, and homogenization functions into a single integrated optical path using a polarizing beam splitter, quarter wave film, and reflector. The illumination beam passes through the same lens array multiple times in sequence, with each pass contributing to speckle reduction and uniformity. This integration simplifies the overall device structure while achieving the speckle minimization effect that would otherwise require multiple separate homogenization elements.
Solution Approach 2:
The lens array serves multiple functions: it acts as both the homogenization element and the imaging lens. By making the lens array multi-functional and having the illumination beam pass through it in sequence multiple times, the system achieves speckle reduction and uniformity without adding separate homogenization components, thereby reducing device complexity.
3Device complexity
If conventional illumination paths are used, then device structure is simple, but light intensity uniformity deteriorates
Solution Approach 1:
The patent implements continuous homogenization by designing an optical path where the illumination beam passes through the same lens array in sequence multiple times. The polarizing beam splitter and quarter wave film enable this repeated traversal, with each pass contributing to uniformity. This continuous action through a single integrated path achieves uniform light intensity while maintaining relatively simple device structure.
Solution Approach 2:
The patent combines multiple optical functions (polarization separation, wave conversion, homogenization, and reflection) into a single integrated optical path. The illumination beam passes through the same lens array multiple times in sequence, with each pass contributing to homogenization. This merging of functions into one path achieves uniform light intensity without requiring multiple separate homogenization elements, thus maintaining structural simplicity.
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 design achieves significant reductions in volume and weight, improves light intensity uniformity, and simplifies manufacturing, with a nearly 80% reduction in projection device volume compared to conventional designs.
Implementation Method 1
The polarizing beam splitter is disposed on a light exit side of the light source. The illumination beam emitted by the light source has a first polarization state
Implementation Method 2
The QWF is disposed between the polarizing beam splitter and the lens array. After the illumination beam is reflected by the first reflector, the illumination beam is converted into a second polarization state different from the first polarization state
Implementation Method 3
The lens array is disposed on one side of the polarizing beam splitter. The lens array is disposed between the QWF and the first reflector
Implementation Method 4
after the illumination beam is reflected by the first reflector, the illumination beam is converted into a second polarization state different from the first polarization state, returns along the first path
Data Source
AI summary
A light source module includes a light source emitting an illumination beam having a first polarization state, a polarizing beam splitter disposed on a light exit side of the light source, a QWF disposed between the polarizing beam splitter and the lens array, a first reflector, and a lens array disposed between the first reflector and the QWF. The illumination beam is transmitted to the polarizing beam splitter, the QWF, the lens array, and the first reflector sequentially; after being reflected by the first reflector to return in a reverse direction, the illumination beam is converted into a second polarization state different from the first polarization state, and is transmitted to and then moved away from the polarizing beam splitter. A projection device having the light source module is also provided.