Two-Mirror Scanning Relay Optics for Compact Color Projection
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Solution Overview
Problem
Existing digital micromirror devices in image projection systems require large and high-intensity light sources and often necessitate color wheels or multiple pixel arrays, limiting the compactness and efficiency of projection systems.
Innovation Solution
An optical projection system utilizing a two-mirror scanning configuration with a first and second microelectromechanical system mirror, each with a distinct scan axis, and an optical relay system comprising various mirror configurations (planar, convex, concave, cylindrical, toroidal, aspherical) to achieve compact, high-efficiency image projection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional digital micromirror devices are used with color wheels or multiple pixel arrays, then full color image projection is achieved, but the system size and complexity increase
Solution Approach 1:
The patent combines multiple pixel arrays (red, green, blue) into a single integrated device structure where each micromirror element can independently control multiple colors. This merging eliminates the need for separate color wheels or multiple independent pixel arrays, reducing system complexity while maintaining full color projection capability.
Solution Approach 2:
Each micromirror element is designed to perform multiple functions by controlling different colors (RGB) simultaneously. The universal micromirror structure can project any color combination, replacing the need for dedicated color-specific hardware components and simplifying the overall system architecture.
2Illumination intensity
If large and high intensity light sources are used, then sufficient illumination for projection is achieved, but the compactness of the system is limited
Solution Approach 1:
The illumination system is segmented into multiple smaller light sources corresponding to different colors (red, green, blue LED sources). Each light source provides targeted illumination for its specific color channel, eliminating the need for a single large high-intensity light source and enabling more compact system design.
Solution Approach 2:
The patent transitions from using a single large light source in one dimension to multiple smaller light sources arranged in a multi-dimensional configuration. This spatial distribution of light sources across different dimensions allows for compact packaging while maintaining sufficient total illumination intensity for projection.
3Ease of manufacture
If conventional optical paths are used without folding, then optical alignment is simpler, but the physical space required increases
Solution Approach 1:
The optical path is folded back on itself using mirrors, transitioning from a linear one-dimensional arrangement to a three-dimensional folded configuration. This allows the optical path to occupy less physical space by utilizing vertical and lateral dimensions, reducing the overall footprint while maintaining the necessary optical path length for proper imaging.
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 system enables compact, efficient projection of two-dimensional and multi-dimensional images while maintaining collimation, allowing for smaller and more versatile projection systems, including head-mounted displays.
Implementation Method 1
the first microelectromechanical system mirror configured or positioned to reflect collimated light from the source along a first range of propagation directions about the first scan axis
Data Source
AI summary
An optical projection system includes a source of collimated light, a first microelectromechanical system mirror positioned to receive collimated light from the source, and an optical relay system positioned to receive collimated light from the first microelectromechanical system mirror. The optical relay system includes a single-pass relay having a first component, a second component, and a third component. The optical projection system also includes a second microelectromechanical system mirror positioned to receive collimated light from the optical relay system and an eyepiece positioned to receive light reflected from the second microelectromechanical system mirror.