Single-DMD Color Projection with Phase-Modulator Bypass
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Solution Overview
Problem
Existing projection systems face challenges in efficiently generating high-quality color images using field sequential projection methods due to the high cost of high-resolution image forming elements like DMDs and the slow response times of phase modulators, which can lead to visible color fields and light degradation issues.
Innovation Solution
Implementing a single DMD with a combination of phase modulators and amplitude modulators, utilizing field sequential techniques to time division multiplex colors and employing methods to direct light directly to the DMD, bypassing the phase modulator when necessary, to enhance light throughput and reduce component costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution image forming elements like DMDs are used in field sequential projection systems, then image quality and color gamut are improved, but system cost increases significantly
Solution Approach 1:
The system divides the projection task into sequential color fields (e.g., red, green, blue) displayed in time-division multiplexing fashion. A single DMD is reused for each color field rather than requiring multiple DMDs for simultaneous color display, reducing component cost while maintaining image quality through rapid field switching that exploits human visual persistence
Solution Approach 2:
The DMD operates in periodic cycles, displaying different color fields in rapid succession (e.g., red field, then green field, then blue field). This periodic operation allows a single DMD to handle all color channels sequentially, eliminating the need for multiple expensive high-resolution DMDs while preserving color gamut and image quality through the persistence of vision effect
2Illumination intensity
If phase modulators are used to steer light in field sequential systems, then light distribution control is improved, but response time increases causing visible color fields and light degradation
Solution Approach 1:
The patent removes the phase modulator from the optical path entirely for certain light paths. Instead of using phase modulators to steer light, the system uses direct illumination approaches where light from the source is directed straight to the DMD and projection lens, eliminating the response time bottleneck and light degradation while maintaining sufficient light distribution control through DMD micromirror positioning
Solution Approach 2:
The DMD micromirrors serve as an intermediary element that can rapidly position light without requiring phase modulation. The micromirrors' fast mechanical response time (microsecond range) replaces the slow phase modulator response, enabling rapid light steering for each color field while maintaining precise light distribution control through electronic addressing of individual micromirors
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 approach allows for high-quality color projection with reduced component costs, improved light handling, and increased efficiency by minimizing light degradation, while maintaining high contrast and color gamut.
Implementation Method 1
directing light of the corresponding color onto a phase modulator that is controlled to provide a phase pattern operative to steer the light of the corresponding color to desired locations on the imaging element
Data Source
AI summary
Image display apparatus and methods may use a single imaging element such as a digital mirror device (DMD) to spatially modulate plural color channels. A color channel may include a light steering element such as a phase modulator. Steered light from a light steering element may be combined with or replaced by additional light to better display bright images. These technologies may be provided together or applied individually.