Switchable Polarization Retarder Array for Zonal Illumination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional illuminators for reflective spatial light modulators (SLMs) in head-mounted display devices are inefficient due to uniform illumination, leading to high power consumption and reduced efficiency, while existing solutions fail to provide compact and lightweight alternatives for selective illumination of small-sized displays.
Innovation Solution
An optical device comprising a waveguide, an array of tunable retarders, and a polarization selective optical element is used to selectively illuminate regions of the SLM, allowing for efficient modulation of light polarization and directional control, thereby reducing power consumption and improving illumination uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If uniform illumination is used for reflective spatial light modulator, then all regions are illuminated, but power consumption increases and efficiency decreases
Solution Approach 1:
The illumination system is divided into multiple independently controllable zones corresponding to different regions of the SLM. Each zone can be selectively illuminated based on demand, rather than illuminating the entire SLM surface uniformly. This segmentation allows only necessary regions to consume power, reducing overall energy consumption while maintaining reliable illumination coverage for active display regions.
Solution Approach 2:
Different regions of the SLM receive illumination selectively based on their specific requirements. The system applies illumination locally to only those zones that need to be active, rather than providing uniform illumination across the entire device. This local quality approach optimizes power consumption by matching illumination distribution to actual display needs.
2Device complexity
If conventional illuminators are used, then simple structure is provided, but illumination efficiency is reduced
Solution Approach 1:
The illumination system transitions from a static, fixed illumination pattern to a dynamic, controllable system. The illumination zones can be actively switched on and off based on real-time display requirements, allowing the system to adapt its illumination pattern dynamically. This dynamic control significantly improves illumination efficiency by ensuring light is delivered only where and when needed, while the underlying structure remains relatively simple.
3Use of energy by moving object
If selective illumination is implemented, then power consumption is reduced, but device complexity increases
Solution Approach 1:
The patent introduces a polarization-selective optical element as an intermediary component that enables selective illumination without requiring complex active control mechanisms for each zone. This optical intermediary uses polarization properties to route light to specific SLM regions, achieving selective illumination through passive optical filtering rather than active electronic control of multiple light sources. This approach reduces power consumption while minimizing the addition of complex control structures.
4Weight of moving object
If compact illumination system is designed, then weight is reduced, but illumination uniformity may be compromised
Solution Approach 1:
The compact illumination system uses segmented illumination zones that are optically separated and independently controlled. Each zone is delivered through distinct optical paths within the compact form factor, ensuring that even though the overall device is lightweight and compact, each illuminated region receives uniform and controlled illumination. The segmentation allows precise control of light distribution without requiring large, heavy optical components.
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 enables efficient, compact, and lightweight illumination of SLMs, reducing power consumption and enhancing illumination uniformity, which is crucial for high-resolution displays in head-mounted devices.
Implementation Method 1
a waveguide
Implementation Method 2
a respective tunable retarder of the array of tunable retarders has a first state, which causes the respective tunable retarder to direct light having a first polarization in a first direction, and a second state, distinct from the first state, which causes the respective tunable retarder to direct light having a second polarization in the first direction
Implementation Method 3
The polarization selective optical element is located adjacent to the array of tunable retarders so that the light having the first polarization propagates from the polarization selective optical element in a second direction and the light having the second polarization propagates from the polarization selective optical element in a third direction distinct from the second direction
Data Source
AI summary
An optical device for illuminating one or more portions of a spatial light modulator includes a waveguide, an array of tunable retarders, and a polarization selective optical element. A respective tunable retarder is optically coupled to receive light from the waveguide. The respective tunable retarder has a first state, which causes the respective tunable retarder to direct light having a first polarization in a first direction, and a second state, which causes the respective tunable retarder to direct light having a second polarization distinct from the first polarization in the first direction. The polarization selective optical element is located adjacent to the array of tunable retarders so that the light having the first polarization propagates from the polarization selective optical element in a second direction and the light having the second polarization propagates from the polarization selective optical element in a third direction distinct from the second direction.