LCOS Illumination Waveguide for Compact AR Light Engine
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Solution Overview
Problem
Traditional LCOS display systems require bulky illumination optics and separate sources for red, green, and blue LEDs, which increase volume and complexity, especially when used in head-mounted displays for augmented or virtual reality applications.
Innovation Solution
The design aligns the illumination system's output with the exit pupil of the projection optics, using a combination of illumination waveguides or prisms to reduce volume and replace traditional optics, allowing for a compact and integrated light engine within head-mounted devices like smart glasses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If traditional separate LED sources and X-cube combiner are used for illumination, then color separation and combination is achieved, but device volume and structural complexity increase
Solution Approach 1:
The patent combines multiple separate LED illumination sources (red, green, blue) and the X-cube combiner into a single integrated illumination waveguide structure. The waveguide integrates the functions of light input, color separation, combination, and directional control into one compact component, eliminating the need for separate optical elements and reducing overall device volume and complexity.
Solution Approach 2:
The illumination waveguide serves multiple functions simultaneously: it acts as the light input channel, the color separation medium (via embedded gratings), the color combination medium, and the directional control element. This multi-functionality replaces the traditional multi-component illumination system with a single universal optical element.
2Illumination intensity
If traditional illumination optics are used in head-mounted displays, then sufficient illumination is provided, but the device becomes too bulky for comfortable wear
Solution Approach 1:
The patent embeds multiple functional elements within the illumination waveguide structure itself. The diffraction gratings for color separation and combination are nested within the waveguide layers, and the multiple LED sources are integrated into the waveguide input face. This nesting approach maintains full illumination functionality while dramatically reducing the external volume of the light engine.
3Adaptability or versatility
If separate red, green, and blue LED sources are used, then full-color display capability is achieved, but the number of optical components and system complexity increase
Solution Approach 1:
The patent merges the functions of three separate LED sources and multiple optical components (lenses, filters, combiners) into a single waveguide structure that handles all three colors simultaneously. The waveguide contains embedded gratings that separate and recombine the red, green, and blue light channels, maintaining full-color capability while eliminating the need for separate optical paths for each color.
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 reduces the volume of illumination optics, enabling a more compact and efficient display system for augmented or virtual reality applications while maintaining image quality and user comfort.
Implementation Method 1
combiner waveguide
Data Source
AI summary
A system comprising an illumination system to direct light from one or more light sources to a limiting output pupil of a projection optomechanical system, a liquid crystal on silicon display panel (LCOS) to modulate the light from the projection optomechanical system and to direct the modulated light back toward the projection optomechanical system, and an in-coupler to a combiner waveguide to receive the modulated light from the LCOS, after it passes through the projection optomechanical system. The system in one embodiment is designed so that the light that passes through the projection optomechanical system from the illumination system lands on the LCOS within the limiting output pupil of the projection optomechanical system.