Scanning Mirror Feedback Control via Photodetector
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Solution Overview
Problem
Existing scanning projectors face challenges in achieving precise control of scanning mirrors due to insufficient monitoring and control techniques, leading to inaccuracies in image quality and performance, especially with temperature and voltage variations.
Innovation Solution
Incorporating at least one photodetector to generate a feedback signal that controls the scanning mirror, allowing for precise control of the scanning mirror's motion by compensating for environmental changes such as temperature and voltage variations, thereby improving image quality and enabling new applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional scanning mirror control techniques are used, then the device complexity is low, but the scanning precision and image quality deteriorate due to insufficient compensation for environmental changes
Solution Approach 1:
The patent implements feedback control by detecting the actual position of the scanning mirror and comparing it with the desired position, then adjusting the drive signal to compensate for deviations caused by environmental changes. This closed-loop system significantly improves scanning precision while managing device complexity through efficient feedback processing.
Solution Approach 2:
The patent replaces traditional mechanical position sensing methods with optical detection using photodetectors to monitor the scanning mirror position. This substitution improves measurement precision without requiring complex mechanical feedback mechanisms, thereby managing overall device complexity.
2Reliability
If environmental compensation mechanisms are added, then the stability against temperature and voltage variations improves, but the device complexity increases
Solution Approach 1:
The system uses feedback control to continuously monitor and compensate for environmental variations. By detecting deviations in scanning mirror position caused by temperature or voltage changes and applying corrective signals, the system maintains high reliability without requiring separate compensation mechanisms for each environmental factor.
Solution Approach 2:
The scanning system performs self-compensation by using its own output (reflected light) to generate feedback signals that automatically correct for environmental disturbances. This self-service approach improves stability without adding external compensation devices, thereby controlling device complexity.
3Manufacturing precision
If photodetectors are used for feedback control, then the scanning precision improves, but the device complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical position sensing systems with optical photodetectors that detect the position of the scanning mirror through light reflection. This substitution achieves high scanning accuracy while reducing mechanical complexity, as photodetectors provide precise position information without requiring complex mechanical feedback linkages.
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 use of photodetectors provides accurate feedback for precise control of scanning mirrors, enhancing image quality and enabling new applications by compensating for environmental changes, ensuring stable and precise scanning performance.
Implementation Method 1
a scanning mirror configured to reflect the laser light; a photodetector configured to receive a portion of the reflected light impacting the over scanned region
Data Source
Figure 1
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Figure 4
AI summary
A scanning projector (100) and method is provided that generates a feedback signal from at least one photodetector (110). In the scanning projector, a scanning mirror (104) is configured to reflect laser light into an image region and an over scanned region. The at least one photodetector is configured to receive a portion of the reflected laser light impacting the over scanned region, and provides the feedback signal responsive to the received portion of light. This feedback signal can then be used to provide precise control of the scanning mirror.