Single-DMD HDR Projection With Phase-Modulated Light Steering
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Solution Overview
Problem
Existing projection systems face challenges in efficiently generating desired patterns of light while minimizing component costs, particularly in high dynamic range (HDR) projection systems that require multiple imaging elements, which can be expensive and prone to degradation due to color-specific light exposure.
Innovation Solution
Implementing a field sequential projection method using a single DMD and a phase modulator, either with multiple phase modulators for each color or a spatially divided phase modulator, combined with direct illumination of the DMD to enhance light throughput and reduce component costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple imaging elements are used in HDR projection systems, then image quality and dynamic range are improved, but system cost and component degradation increase
Solution Approach 1:
The patent segments the imaging function across multiple DMD devices, with each DMD handling specific color fields (red, green, blue) in a field-sequential manner. This allows the system to achieve HDR performance through temporal and spectral separation rather than requiring multiple simultaneous imaging elements, thereby reducing system complexity and cost while maintaining image quality.
Solution Approach 2:
The system employs field-sequential color projection where each DMD device operates periodically to display different color fields in rapid succession. The DMDs are refreshed at different times within each frame cycle, allowing sequential illumination and reducing the need for multiple continuously operating imaging elements. This periodic operation maintains high image quality while minimizing component degradation from continuous exposure to intense color-specific light.
2Measurement precision
If multiple phase modulators are provided for each color, then color accuracy is improved, but device complexity and cost increase
Solution Approach 1:
Each DMD device serves multiple functions: it acts as both the phase modulator and the imaging element for its assigned color field. The DMDs are configured with specific optical properties (phase shift ranges, reflectivity characteristics) that enable them to perform both light modulation and spatial light modulation functions simultaneously. This multi-functionality eliminates the need for separate phase modulators for each color, reducing device complexity while maintaining color accuracy through field-sequential operation.
3Illumination intensity
If light throughput is increased, then brightness is improved, but component degradation accelerates
Solution Approach 1:
The system uses field-sequential color projection where each DMD device is illuminated by intense color-specific light only during its assigned field period, rather than continuously. Each DMD receives high-intensity light for approximately one-third of the frame time (for RGB fields), significantly reducing cumulative light exposure and thermal stress while maintaining high brightness during active periods. This periodic illumination pattern extends component lifespan while preserving brightness performance.
Solution Approach 2:
Each DMD device is optimized with specific optical properties tailored to its assigned color field, including phase shift characteristics and reflectivity properties matched to the wavelength range of its color. This local optimization allows each component to operate at peak efficiency for its specific function, maximizing light throughput and brightness during active periods while minimizing unnecessary exposure to other wavelengths that would accelerate degradation.
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 method achieves high light throughput, improved contrast, and reduced component costs by efficiently steering and combining light using a single DMD and phase modulator, while minimizing degradation and maintaining color accuracy.
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.