Compact Illuminator for Wearable Displays Using Waveguide and Lens Arrays
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Solution Overview
Problem
Conventional wearable displays are often heavy, large, and lack see-through capabilities with low resolution, and existing illuminators for these devices face challenges in providing uniform light distribution and compact form factors, especially for eye-glass type displays.
Innovation Solution
A compact illuminator design that uses an expander lens, collimation lens, and micro-lens arrays to achieve a large divergent angle of light beams, combined with a homogenizer and polarized beam splitter, to create a high-resolution see-through display with a large eyebox, and incorporates solid-state light sources and diffractive optical elements for efficient light combination and distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional near eye displays (Head Mount Display, Head up Display, Eye Glass Type Display) are used, then see-through capability is provided, but the devices are too heavy, too large, and have low resolution
Solution Approach 1:
The optical system is segmented into distinct functional components: waveguide layer for light propagation, coupler layer for light injection, and display element for image generation. This segmentation allows each component to be optimized independently, reducing overall weight while maintaining see-through capability
Solution Approach 2:
The display system is nested within the eyeglass frame structure, with the waveguide and optical components integrated into the temple or bridge area. This nesting approach minimizes the visible profile and distributes weight across the glasses structure rather than concentrating it in one location
2Adaptability or versatility
If conventional near eye displays are used, then see-through capability is provided, but the devices are too large
Solution Approach 1:
The display screen is extracted from the traditional front lens position and relocated to the temple or bridge area of the eyeglasses. This extraction allows the optical path to be folded back through the waveguide, significantly reducing the front profile and overall device size while preserving see-through functionality
Solution Approach 2:
The optical system transitions from a two-dimensional planar layout to a three-dimensional folded path using the waveguide. Light travels from the display element through the coupler into the waveguide, propagates along the waveguide layer, and exits toward the user's eye, creating a compact volumetric configuration that minimizes device dimensions
3Adaptability or versatility
If conventional near eye displays are used, then see-through capability is provided, but the displays have low resolution
Solution Approach 1:
The traditional mechanical projection system is replaced with a waveguide-based optical system that uses total internal reflection and diffractive optics to guide and focus light. This substitution enables higher resolution by maintaining precise optical control without the mechanical limitations of conventional projection mechanisms
Solution Approach 2:
The waveguide layer serves multiple functions simultaneously: it guides light from the display element, maintains image resolution through controlled total internal reflection, and enables see-through capability by allowing ambient light to pass through. This multi-functionality achieves high resolution without requiring separate optical components for each function
4Ease of manufacture
If conventional wearable displays are used, then display functionality is provided, but they do not provide see-through view and are expensive
Solution Approach 1:
The waveguide layer and display element are merged into an integrated optical assembly where the waveguide serves as both the light guide and the structural support for the display components. This merging reduces the number of separate parts and interfaces, simplifying manufacturing and reducing costs while maintaining see-through capability
5Illumination intensity
If display systems with LED and Laser light sources are used, then brightness is improved, but uneven distribution of light intensity occurs requiring a homogenizer
Solution Approach 1:
The illuminator provides non-uniform light distribution optimized for specific regions: higher intensity at the edges of the display element where total internal reflection is most effective, and adjusted intensity in the center region. This local quality optimization eliminates the need for homogenizing optics while maintaining overall image uniformity
6Ease of manufacture
If three separate color light sources are combined into a single light beam, then full-color display is achieved, but the system size increases
Solution Approach 1:
Three separate illuminators for red, green, and blue light sources are merged into a single integrated illuminator structure that shares common optical components including the expander lens, collimation lens, and waveguide interface. This merging reduces the overall volume while maintaining full-color display capability through sequential or simultaneous activation of the three light sources
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 a lightweight, compact, high-resolution see-through display with a large viewing angle, improving the eyebox size and ensuring comfortable image viewing with minimal detectability, while reducing the size and cost of the illuminator system.
Implementation Method 1
an expander lens, collimation lens, and micro-lens arrays to achieve a large divergent angle of light beams
Implementation Method 2
an expander lens, collimation lens, and micro-lens arrays to achieve a large divergent angle of light beams
Implementation Method 3
an expander lens, collimation lens, and micro-lens arrays to achieve a large divergent angle of light beams
Implementation Method 4
combined with a homogenizer and polarized beam splitter, to create a high-resolution see-through display
Implementation Method 5
combined with a homogenizer and polarized beam splitter, to create a high-resolution see-through display
Implementation Method 6
Illuminator for a wearable display... projecting an image to a diffractive optical element
Data Source
AI summary
A compact illuminator for a see-through image display system with highly uniform light distribution is disclosed. This invention enables wearable displays such as eye-glass type see-through display. This system provides a wide divergent beam from a display device so that a viewer can have a large eyebox.