Solid State Light Source Drive Control for Projector Energy Efficiency
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Solution Overview
Problem
Conventional solid state light source systems for high luminance applications, such as projection displays, suffer from low energy efficiency due to unnecessary energy wastage when using multiple light sources, as only one color segment is active at a time, while others are inactive, leading to inefficient use of energy and heat generation.
Innovation Solution
A method and apparatus for controlling solid state light sources in a projector system, where two or more light sources are independently driven based on a sync signal to alternate between active and inactive states during each rotation period of the color wheel, ensuring that only necessary light sources are active, thereby reducing energy consumption and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If multiple solid state light sources are used to generate different color lights for projection display, then the luminance output and color quality are improved, but energy consumption increases due to unnecessary energy wastage when only one color segment is active at a time
Solution Approach 1:
The patent implements periodic action by alternating between different solid state light sources based on the color wheel's rotation. The controller activates specific light sources (e.g., UV/ blue SSL source for red and green lights, second SSL source for blue light) during specific time intervals corresponding to each color segment's position, rather than keeping all light sources continuously active. This periodic activation pattern reduces energy consumption while maintaining the required luminance output for each color.
Solution Approach 2:
The patent applies dynamics by making the light source activation state changeable and adaptive. The controller dynamically adjusts the on/off state of each solid state light source based on real-time feedback from the color wheel position, allowing the system to transition between different operational modes (e.g., activating first SSL source when color wheel indicates red/green segment, activating second SSL source when blue segment is indicated). This dynamic control optimizes energy usage while preserving luminance performance.
2Illumination intensity
If multiple solid state light sources operate continuously to ensure sufficient luminance output, then the illumination intensity is maintained, but heat generation increases leading to overheating issues
Solution Approach 1:
The patent uses periodic action to reduce heat generation by activating light sources only during the time intervals when they are needed for color generation. Instead of continuous operation, the controller periodically switches between different light sources synchronized with the color wheel rotation, allowing each light source to operate at full power only when its emitted light is required, thereby reducing cumulative heat accumulation while maintaining adequate luminance output.
Solution Approach 2:
The patent implements dynamic control of light source operation to manage thermal output. The controller adjusts the operational state of each solid state light source based on the color wheel's position, dynamically turning on specific sources (e.g., UV/blue SSL source for red/green colors, second SSL source for blue color) only when necessary. This dynamic state changeability prevents continuous high-power operation and associated overheating problems while ensuring sufficient luminance is delivered during active periods.
3Stability of the object's composition
If all solid state light sources are driven in constant current mode to maintain stable output, then the luminance stability is improved, but energy efficiency deteriorates due to inability to optimize for sequential color light requirements
Solution Approach 1:
The patent applies dynamics by transitioning from static constant current mode to dynamic current control mode. The controller adjusts the drive current of each solid state light source based on the color wheel's position and the corresponding color generation requirements. During periods when a light source is inactive, the controller reduces or stops the drive current, and during active periods, it optimizes the current to achieve the required luminance. This dynamic current adjustment maintains luminance stability during active operation while significantly improving overall energy efficiency compared to constant current mode.
Solution Approach 2:
The patent implements parameter changes by varying the drive current parameter of each solid state light source according to operational requirements. Instead of maintaining a fixed constant current, the controller changes the current parameter dynamically based on the color wheel segment position and the specific color light being generated. This parameter adjustment allows the system to maintain stable luminance output during active periods while reducing energy consumption during inactive periods, thereby resolving the contradiction between luminance stability and energy efficiency.
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 energy efficiency and luminance output by allowing light sources to operate at higher power during active periods, reducing waste and overheating, while maintaining the same luminance levels, thus providing a more efficient and cost-effective light source module.
Implementation Method 1
solid state light sources for generating at least two corresponding lights of different colors
Implementation Method 2
a UV or blue SSL source generates a UV or blue light which excites a wavelength conversion material such as a phosphor carried on a wheel to generate a wide spectrum light
Implementation Method 3
The color wheel 204 has several filter segments that filters the white light into primary color lights
Data Source
AI summary
A solid state light source module includes two solid state light sources, a light combining device for combining the lights from the two sources, a color wheel receiving the combined light and alternatingly outputting at least two primary color lights, a sync signal generator coupled to the color wheel for generating a periodic sync signal, and a controller for supplying a drive signal to each solid state light sources based on the sync signal. During at least one sub-period of the period, one of the two solid state light sources is turned on by its drive signal and the other one is kept in an inactive state by its drive signal.