Optical Suspension for Projector Pixel Pitch and Image Centering
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Solution Overview
Problem
Current DLP and LCD projection systems, as well as 3D printing technologies, face limitations in image quality and resolution due to fixed pixel pitch and throw distance, leading to image overspill, skewing, and reduced accuracy in printing, especially in confined spaces, and are unable to achieve the necessary high resolution for microfluidic and MEMS device fabrication.
Innovation Solution
An optical suspension system with adjustable components, including spacers, springs, and fastening systems, is introduced to alter the distance between the projector optics and the DMD, allowing for smaller pixel pitches and improved image centering, which can be retrofitted to standard projectors to enhance resolution and reduce distortions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the projector optics are fixed at a standard distance from the DMD, then the device structure is simple and easy to manufacture, but the pixel pitch cannot be reduced below the manufacturer's limit and image quality deteriorates in confined spaces
Solution Approach 1:
The patent implements a dynamic optical suspension system that allows the projector optics to be adjusted to different distances from the DMD. The suspension system includes adjustable spacers and positioning mechanisms that enable continuous variation of the optical distance, thereby dynamically changing the pixel pitch from the manufacturer's fixed limit down to half the wavelength of light. This dynamic adjustment capability resolves the contradiction by making the previously fixed parameter variable while maintaining manufacturing feasibility through modular spacer components.
Solution Approach 2:
The invention changes the physical parameter of optical distance between the projector lens and DMD by introducing adjustable spacers and suspension elements. By varying this distance parameter, the system achieves different pixel pitches without changing the fundamental projector architecture. The spacers come in different thicknesses (e.g., 0.5mm, 1mm, 2mm) allowing precise control of the optical path length and resulting pixel pitch, thus enabling high-resolution imaging while keeping the device manufacturable.
2Manufacturing precision
If the optics are not precisely centered over the projection beam, then the device assembly is easier and faster, but image artifacts such as keystone effects and barrel distortion increase
Solution Approach 1:
The suspension system incorporates self-aligning features where the optics automatically center themselves over the projection beam through the suspension mechanism's design. The system includes reference marks, alignment pins, or self-centering spring mechanisms that guide the optics into the correct position during assembly, eliminating the need for complex manual alignment procedures. This self-service approach achieves precise image centering while maintaining ease of manufacture through intuitive assembly processes.
Solution Approach 2:
The patent replaces complex mechanical alignment systems with a simplified suspension-based positioning mechanism. Instead of requiring precision mechanical mounts and manual adjustment procedures, the system uses elastic suspension elements and gravity-assisted positioning to achieve automatic centering. This substitution reduces manufacturing complexity while maintaining or improving alignment precision through the inherent properties of the suspension system.
3Manufacturing precision
If additional reducing optics are installed to decrease pixel pitch, then the resolution improves, but the system complexity increases and the native pixel limit of approximately 50 μm cannot be overcome
Solution Approach 1:
The invention achieves pixel pitch reduction by changing the fundamental parameter of optical distance rather than adding complex reducing optics. By adjusting the distance between the projector lens and DMD using adjustable spacers, the system directly controls the projected pixel size without requiring additional lenses or optical elements. This parameter change approach achieves pixel pitches below the native 50μm limit while keeping the optical system relatively simple and avoiding the complexity of multi-lens assemblies.
Data Source
AI summary
A suspension system including a set of optics which adjust the size and focus of the projection image originating at a Digital Micro-Mirror Device mirror set. The suspension and adjustment system for these optics may be mounted between the Digital Micro-Mirror Device housing and the optics carrier. This system has the capability to both adjust the resulting size and focus of the image at the same distance to a wall, as well as adjust for out-of-plane issues which often result in skewed images. This results in an adjustable focal and image size differing from the manufacturer's intended throw pattern and allowing broader use of the projector to make smaller images at the same throw distance.