Projector Phosphor Wheel Synchronization Control
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Solution Overview
Problem
The use of a phosphor wheel and color wheel in projectors leads to deterioration in gradation reproducibility due to synchronization errors, resulting in reduced brightness when using light from spoke regions to create white light.
Innovation Solution
A projector system with a phosphor wheel and color wheel that includes marks for synchronization, a DMD for modulation, and a control unit that adjusts the rotation of both wheels based on reference signals to ensure accurate illumination and modulation, optimizing the timing for uniform gradation reproducibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light from spoke regions is used to create white light, then brightness is improved, but gradation reproducibility deteriorates
Solution Approach 1:
The patent extracts and eliminates the problematic spoke regions from the optical path by adjusting the illumination beam diameter and positioning it to pass only through the phosphor wheel and color wheel regions, avoiding the spoke regions that cause synchronization errors and gradation deterioration
Solution Approach 2:
The patent changes the parameter of beam diameter to optimize the illumination path, ensuring that light passes through regions that maintain both brightness and gradation reproducibility by avoiding spoke regions
2Manufacturing precision
If phosphor wheel and color wheel rotate in synchronization, then gradation reproducibility is improved, but synchronization errors occur due to wheel errors
Solution Approach 1:
The patent employs feedback mechanisms through detectors that monitor the rotational positions of the phosphor wheel and color wheel, providing signals to the control unit to continuously adjust and maintain precise synchronization, compensating for wheel errors
Solution Approach 2:
The patent replaces purely mechanical synchronization with an optoelectronic control system that uses detectors and control units to monitor and adjust wheel positions, providing more accurate and reliable synchronization
3Adaptability or versatility
If multiple wheels are used in the projector, then color performance is improved, but device complexity increases
Solution Approach 1:
The patent combines the phosphor wheel and color wheel into a single synchronized rotation system, merging their functions to achieve superior color performance while managing complexity through integrated control rather than separate independent systems
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
Ensures uniform gradation reproducibility even with errors in the phosphor and color wheels by synchronizing their rotation and modulation, enhancing image quality by maintaining brightness and gradation consistency.
Implementation Method 1
phosphors 1012-1014 that are excited by incident light to emit yellow fluorescence
Implementation Method 2
Polarization beam splitter 203 transmits P-polarized light and reflects S-polarized light
Implementation Method 3
after having passed two times through quarter-wave plate 201, is irradiated into polarization beam splitter 205 in a P-polarized state
Data Source
AI summary
In order to ensure uniform gradation reproducibility even when an error occurs in a phosphor wheel or a color wheel, an image in which gradations change in steps is displayed and the rotation operation of a phosphor wheel and a color wheel is controlled on the basis of color coordinate values of each gradation that are measured each time the input timings of the first reference signal and the second reference signal are changed a plurality of times.