Projector Light Modulator Control for Stable Dark Pixel Color
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Solution Overview
Problem
Power consumption and heat production in projectors, particularly cinema projectors, are exacerbated by dimming techniques that affect the color stability of lowest brightness and/or black pixels due to varying light source brightness across image frames.
Innovation Solution
A controller dynamically adjusts the light source brightness and light modulator throughput to maintain a constant low brightness output for lowest brightness regions, using a headroom-based approach to reduce power consumption and heat production while stabilizing pixel colors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If light source brightness is reduced to lower power consumption and heat production, then energy efficiency improves, but color stability of lowest brightness pixels deteriorates
Solution Approach 1:
The patent applies local quality by treating different brightness regions of the image differently. Highest brightness pixels receive full light source intensity, while lowest brightness pixels receive reduced intensity. This spatial differentiation allows power consumption to be reduced without affecting the color stability of dark regions, as they are specifically protected from the full impact of light source dimming.
Solution Approach 2:
The patent implements dynamic control of light source brightness based on the specific requirements of each image frame. The controller adjusts the light source intensity dynamically, reducing it only when and where appropriate, rather than maintaining a fixed reduced intensity. This dynamic approach optimizes power consumption while preserving color stability in lowest brightness regions across varying image content.
2Temperature
If light source brightness is reduced to decrease heat production, then thermal management improves, but brightness consistency across image frames deteriorates
Solution Approach 1:
The patent applies local quality by selectively reducing light source brightness only for lowest brightness regions while maintaining full brightness for highest brightness regions. This localized approach decreases overall heat production without creating brightness inconsistency, as each region receives appropriate intensity levels that maintain their relative brightness relationships across image frames.
Solution Approach 2:
The patent changes the light source brightness parameter dynamically based on image frame characteristics. By adjusting this parameter selectively for different brightness regions and different frames, the system reduces heat production while maintaining brightness consistency, as the parameter changes are optimized to preserve the intended visual output.
3Use of energy by moving object
If light source brightness is dynamically adjusted to optimize power consumption, then energy efficiency improves, but color accuracy of lowest brightness pixels deteriorates
Solution Approach 1:
The patent applies local quality by implementing region-specific brightness control where lowest brightness pixels are treated differently from other regions. This allows the system to reduce power consumption through selective dimming while preserving color accuracy in the darkest regions, as they are specifically protected from the full impact of power-saving measures.
Solution Approach 2:
The patent implements feedback control where the controller monitors image frame characteristics and adjusts light source brightness accordingly. This feedback mechanism ensures that power consumption is optimized while color accuracy is maintained, as the system continuously adapts to preserve the intended color representation in lowest brightness regions.
Data Source
AI summary
A projector includes a light modulator, and a controller communicatively coupled to: an image source that provides frames to drive the light; and a light source arranged to illuminate the modulator according to colors. The controller, for a given image frame and given color: determines headroom of highest brightness pixels of the given frame, the headroom representing a difference between a peak brightness of a peak throughput of the modulator and a respective highest brightness associated with the highest brightness pixels; reduces a light source brightness to correspond to a peak light source brightness reduced by the headroom; controls highest brightness regions of the modulator to the peak throughput; and, based on reduced light source brightness, the controller controls lowest brightness regions of the modulator to a respective low-brightness throughput that maintains an about constant given low brightness output by the lowest brightness regions of the modulator across the frames.