Projection System DMD Stray Light Reduction via Dynamic Illumination
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Solution Overview
Problem
Existing projection systems suffer from low contrast due to stray light generated when the mirror units of a DMD are in the 'OFF' state, which reduces the overall image quality.
Innovation Solution
The system adjusts the divergence angle of the illumination light to minimize stray light by reducing the luminous flux and increasing the grayscale values of pixels, thereby reducing the 'OFF' time duration of the mirror units, which improves the contrast by reducing the influence of stray light on the projection system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the luminous flux of illumination light is reduced to minimize stray light, then the contrast is improved, but the brightness of the projection image is reduced
Solution Approach 1:
The patent applies dynamic adjustment of the light source luminous flux based on the grayscale values of pixels in the image data. The control unit dynamically modifies the luminous flux in real-time according to the distribution of grayscale values, allowing the system to adapt to different image content and maintain optimal contrast while compensating for brightness loss through coordinated grayscale value adjustments.
Solution Approach 2:
The patent changes the luminous flux parameter of the illumination light based on the grayscale value distribution in the image. By adjusting this physical parameter dynamically, the system optimizes the balance between contrast improvement (reduced stray light) and brightness maintenance, resolving the technical contradiction between these two opposing requirements.
2Illumination intensity
If the grayscale values of pixels are increased to compensate for brightness loss, then the brightness is improved, but the contrast is reduced due to increased OFF time duration
Solution Approach 1:
The control unit implements a feedback mechanism that monitors the grayscale value distribution in the image data and uses this information to adjust the luminous flux of the light source. This closed-loop control allows the system to coordinate the relationship between brightness compensation and contrast maintenance, preventing the degradation of contrast that would result from simply increasing grayscale values.
Solution Approach 2:
The system dynamically coordinates the adjustment of both luminous flux and grayscale values based on real-time image content analysis. This dynamic coordination ensures that brightness compensation does not come at the cost of contrast degradation, as the system adapts its parameters continuously rather than using fixed adjustments.
3Ease of manufacture
If the divergence angle of illumination light is reduced to minimize stray light, then the contrast is improved, but the illumination area is reduced
Solution Approach 1:
The patent changes the divergence angle parameter of the illumination light based on the grayscale value distribution in the image data. By dynamically adjusting this optical parameter, the system optimizes the balance between contrast improvement (reduced stray light) and illumination area coverage, resolving the technical contradiction between these two requirements.
Solution Approach 2:
The system dynamically adjusts the divergence angle of the illumination light in real-time according to the image content. This dynamic optical parameter adjustment allows the system to maintain optimal contrast while compensating for illumination area reduction, adapting to different scene requirements rather than using a fixed divergence angle.
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 enhances the dynamic contrast of the projection system by accurately restoring original grayscale values and reducing stray light, leading to improved image quality closer to human perception ranges.
Implementation Method 1
The light emitting device is configured to emit the illumination light and adjust a divergence angle of the illumination light, in such a manner that the luminous flux of the adjusted illumination light is adapted to the increased grayscale value
Data Source
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AI summary
A projection system includes a signal processor, a light source, an optical relay system, an adjusting member, and a DMD. The signal processor receives image data. The signal processor increases grayscale values of pixels of the image data. The light source is used for emitting illumination light. The optical relay system provides the illumination light to the DMD for modulating to obtain projection light required for a projection image. The adjusting member reduces the luminous flux of the illumination light provided to the DMD when the grayscale values of the pixels of the image data are increased. A reduction ratio of the luminous flux of the illumination light matches an increase ratio of the grayscale values of the image data. The DMD modulates the adjusted illumination light according to the image data with increased grayscale values to generate the projection light required for the projection image.