Wedge Light Turning for Compact Spatial Light Modulator Illumination
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Solution Overview
Problem
Conventional illumination systems for spatial light modulators, such as those using polarizing beam splitters, are bulky and require reduction in size to facilitate smaller display systems, particularly in augmented reality applications.
Innovation Solution
The implementation of compact polarization beam splitting components and illumination systems that direct light with specific polarization states to spatial light modulators, utilizing wedge-shaped light turning elements and polarization sensitive light turning elements to reduce the size of polarizing beam splitters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional polarizing beam splitters are used in illumination systems, then light polarization control is achieved, but the system size increases and miniaturization is hindered
Solution Approach 1:
The patent extracts the polarization beam splitting function from a conventional bulky polarizing beam splitter and implements it through a combination of a wedge-shaped light turning element and a polarization sensitive reflector. This separation of functions allows the system to achieve polarization control without the large size of traditional beam splitters, directly resolving the contradiction between polarization control capability and system miniaturization
Solution Approach 2:
The patent introduces a polarization sensitive reflector as an intermediary element that works in conjunction with the wedge-shaped light turning element. This intermediary component enables polarization-selective reflection to redirect light toward the spatial light modulator, achieving the function of a polarizing beam splitter in a compact configuration and resolving the size-polarization control contradiction
2Volume of moving object
If a compact illumination system is used to reduce size, then miniaturization is achieved, but depth perception capability may be compromised
Solution Approach 1:
The patent incorporates a waveguide stack that introduces multiple depth planes by utilizing the vertical dimension. The waveguide stack includes multiple waveguides positioned at different depths, each contributing to the three-dimensional imagery. This dimensional approach enables realistic depth perception while maintaining a compact overall system footprint, resolving the contradiction between miniaturization and depth perception quality
3Manufacturing precision
If waveguide stack is added for depth perception, then three-dimensional imagery quality is improved, but device complexity increases
Solution Approach 1:
The patent merges the waveguide stack with the existing illumination system components, integrating the depth perception functionality into the compact illumination architecture. The waveguide stack is positioned to receive light from the wedge-shaped light turning element and spatial light modulator, combining multiple functions (illumination, modulation, and depth perception) into a unified compact system, thereby reducing the overall device complexity despite adding depth perception capability
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 configuration allows for more compact display systems by minimizing the size of polarizing beam splitters while effectively illuminating spatial light modulators, enhancing the integration of augmented reality technology.
Implementation Method 1
a wedge-shaped light turning element to direct light having a first polarization state towards a spatial light modulator
Implementation Method 2
direct light reflected from the spatial light modulator having a second polarization state different from the first polarization towards a viewer
Implementation Method 3
The illumination systems contemplated herein can be configured as polarization beam splitting components having a reduced size
Implementation Method 4
spatial light modulators (e.g., liquid crystal on silicon (LCOS) devices)
Implementation Method 5
incorporating a waveguide stack to simulate multiple depth planes for enhanced depth perception
Data Source
AI summary
An optical device may include a light turning element. The optical device can include a first surface that is parallel to a horizontal axis and a second surface opposite to the first surface. The optical device may include a light module that includes a plurality of light emitters. The light module can be configured to combine light from the emitters, for example using at least one dichroic combiner and/or a light integrator. The optical device can further include a light input surface that is between the first and the second surfaces and is disposed with respect to the light module to receive light. The optical device may include an end reflector that is disposed on a side opposite the light input surface. The light coupled into the light turning element may be reflected by the end reflector and/or reflected from the second surface towards the first surface.