DMD Illumination Lens Decentration for Contrast-Stable Projection
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Solution Overview
Problem
Existing projection systems face challenges in maintaining proper illumination angles and contrast ratios due to variations in the angle of incidence on digital micromirror devices (DMDs), leading to degradation in projected image quality.
Innovation Solution
A projection system utilizing dual lens groups for lateral adjustment to maintain the correct illumination angle on DMDs, compensating for deviations in micromirror angles, ensuring the beam is centered and aligned with the aperture, and employing a controller to actuate these adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a semi-collimated illumination system with a small aperture stop is used to improve contrast ratio, then the contrast ratio and clarity of the projected image are improved, but the system becomes highly sensitive to illumination angle variations on the DMD
Solution Approach 1:
The patent implements dynamic adjustment of the illumination angle by making the aperture stop movable relative to the DMD. The aperture stop can be positioned at different locations along the optical path to change the effective illumination angle on the DMD mirrors. This dynamic positioning allows the system to adapt to manufacturing tolerances and maintain optimal contrast ratio without requiring precise fixed-angle illumination, thereby resolving the contradiction between achieving high contrast and reducing sensitivity to angle variations.
2Measurement precision
If the aperture stop is positioned to optimize contrast, then image quality is improved, but manufacturing and alignment precision requirements increase
Solution Approach 1:
The aperture stop is designed with movable capability along the optical path, allowing it to be dynamically positioned to compensate for manufacturing tolerances in the DMD mirror angles. This dynamic adjustment mechanism enables the system to achieve optimal image quality and contrast ratio without requiring extremely tight manufacturing precision, as the aperture stop can be repositioned during assembly or operation to account for variations in DMD fabrication.
3Device complexity
If fixed illumination angle is used to simplify system design, then device complexity is reduced, but image clarity and contrast ratio deteriorate due to angle variations
Solution Approach 1:
The illumination system incorporates a movable aperture stop that can be dynamically adjusted along the optical path. This dynamic element allows the system to maintain optimal illumination angles and achieve high image clarity and contrast ratio without requiring an overly complex fixed-angle illumination design. The simplicity of the movable aperture mechanism provides an elegant solution that balances device complexity with image quality requirements.
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 achieves high dynamic range and resolution by maintaining image clarity and contrast ratio, even with variations in DMD mirror angles, enhancing image projection quality.
Implementation Method 1
A projection system and method are disclosed that utilize lens decentration to adjust an illumination angle on the DMD
Implementation Method 2
a digital micromirror device including a plurality of micromirrors, wherein a respective micromirror is configured to reflect the steered light to a predetermined location as on-state light
Data Source
AI summary
A projection system and calibration method therefor relate to a light source configured to emit a light in response to an image data, an illumination optical system configured to steer the light, the illumination optical system including a first lens group and a second lens group, a digital micromirror device (DMD) including a plurality of micromirrors respectively configured to reflect the steered light to a predetermined location as on-state light or to reflect the steered light as off-state light to a light dump; determining a deviation between an actual angle of orientation and an expected angle of orientation of a respective micromirror of the plurality of micromirrors; calculating a first amount of lateral adjustment corresponding to the first lens group and a second amount of lateral adjustment corresponding to the second lens group, and actuating the first and second lens groups according to the corresponding first and second amount.