Light Source Module for LCOS Projectors Reducing Volume and Light Loss
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Solution Overview
Problem
Conventional projectors with liquid-crystal-on-silicon (LCOS) panels face issues of bulkiness due to the space occupied by polarizing beam splitters and significant light loss when using unpolarized illumination beams, which reduces the efficiency of the optical system.
Innovation Solution
A light source module incorporating a light-emitting device, a light guide pipe with recessed and convex surfaces, a wave plate, and a polarizer, where the light guide pipe recycles light by reflecting a portion of the beam back through the wave plate and polarizer, reducing light loss and system volume.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a polarizing beam splitter (PBS) is disposed in front of the LCOS panel to filter out a beam with unwanted polarization direction, then the polarization filtering function is improved, but the optical system volume becomes too bulky and light loss increases
Solution Approach 1:
The patent combines the polarizer and PBS into a single integrated component called a 'polarizing beam splitter module' that merges the polarization filtering function with the beam splitting function. This integration eliminates the need for separate PBS and reduces the overall optical system volume while maintaining the polarization filtering capability.
Solution Approach 2:
The patent implements a nested structure where the polarizer is positioned within the light guide pipe, and the beam path is folded back through the light guide pipe to return to the polarizer. This nesting arrangement allows multiple optical functions to be performed within a compact volume, reducing the overall system size.
2Reliability
If a polarizing beam splitter (PBS) is used to filter out unwanted polarization direction, then the polarization filtering function is improved, but light loss increases due to only half the illumination beam being transmitted
Solution Approach 1:
The patent creates a feedback mechanism where the beam path is folded back through the light guide pipe to return to the polarizer. The reflected beam from the PBS is guided back through the light guide pipe to re-pass through the polarizer, allowing the system to recycle and reuse light that would otherwise be lost, thereby reducing overall light loss while maintaining polarization filtering.
Solution Approach 2:
Instead of discarding the reflected beam from the PBS as lost light, the patent recovers it by guiding it back through the light guide pipe to re-pass through the polarizer. This recovery mechanism allows the system to reuse light energy that would otherwise be wasted, reducing light loss while maintaining the polarization filtering function.
3Device complexity
If a conventional light guide pipe is used, then the structure is simple, but the optical system volume remains large and light recycling is insufficient
Solution Approach 1:
The patent employs curved surfaces (convex and concave) on the light guide pipe to control and redirect the beam path. These curved surfaces enable the beam to be folded back through the light guide pipe in a compact arrangement, reducing the overall optical system volume while maintaining structural simplicity.
Solution Approach 2:
The patent utilizes the three-dimensional space within the light guide pipe by creating a folded beam path that returns through the polarizer. This dimensional arrangement allows the system to achieve compact volume reduction by efficiently utilizing spatial dimensions rather than simply extending components linearly.
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 light source module reduces light loss by recycling light and minimizes the optical system's volume through a compact structure, allowing for more efficient illumination of the LCOS panel.
Implementation Method 1
at least a portion of the second part of the beam is reflected by at least one of the recessed curved surface, the first convex surface, and the second convex surface, so as to travel back to the wave plate and the polarizer
Implementation Method 2
The polarizer is disposed on a path of the beam from the wave plate and configured to allow a first part of the beam having a first polarization direction to pass through, and reflect a second part of the beam having a second polarization direction
Data Source
AI summary
A light source module includes a light-emitting device, a light guide pipe, a wave plate, and a polarizer. The light-emitting device emits a beam. The light guide pipe includes a recessed curved surface, an output surface, a first convex surface, and a second convex surface. The recessed curved surface faces the light-emitting device. The output surface is opposite to the recessed curved surface. The first convex surface connects the recessed curved surface with the output surface. The second convex surface connects the recessed curved surface with the output surface and is opposite to the first convex surface, wherein the beam enters the light guide pipe through the recessed curved surface, and leaves the light guide pipe through the output surface. The wave plate is disposed on a path of the beam from the output surface. The polarizer is disposed on a path of the beam from the wave plate.