Lens Shift Mechanism Central Position Detection Control
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Solution Overview
Problem
Existing lens shift mechanisms in projection image display devices face challenges in accurately returning the projection lens to its central position due to the limitations of optical sensors' detection widths and varying stopping positions based on travel direction, leading to manufacturing cost increases and reduced accuracy.
Innovation Solution
A lens shift mechanism with a control system that uses a combination of sensors to detect the central position and adjust the drive mechanism's operations, allowing the projection lens assembly to travel in specific directions and speeds to accurately return to the central position without the need for precise hardware configurations or narrow detection widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a sensor with narrow detection width is used to detect the central position, then measurement precision is improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The detection process is segmented into multiple operations: a first operation to detect when the projection lens passes through one end of the detection width, and a second operation to detect when it passes through the other end. By dividing the detection into sequential steps rather than requiring a single precise detection point, the system achieves accurate central position detection without needing a sensor with extremely narrow detection width.
Solution Approach 2:
The control section performs preliminary actions by detecting the passage through the detection width boundaries before determining the central position. The system first detects when the lens assembly enters the detection width range, then detects when it exits, and only after these preliminary detections does it calculate the central position. This preliminary detection approach allows using sensors with wider detection widths while maintaining precision.
2Productivity
If the projection lens assembly travels at high speed to improve productivity, then productivity is improved, but measurement precision of central position detection deteriorates
Solution Approach 1:
The control section uses feedback from the central position detection section to adjust the driving mechanism's operation. By continuously monitoring the detection width passage and using this feedback to determine when the central position has been reached, the system can accurately stop regardless of travel speed. The feedback loop allows high-speed operation while maintaining detection accuracy through real-time position information.
Solution Approach 2:
The system dynamically adjusts its detection and control operations based on the lens assembly's motion state. The control section monitors the passage through detection width in real-time and dynamically determines the central position based on the detected timing. This dynamic approach allows the system to maintain accuracy whether the lens assembly is moving quickly or slowly, adapting the detection process to the current motion conditions.
3Ease of manufacture
If the detection width is widened to reduce manufacturing precision requirements, then ease of manufacture is improved, but measurement precision of central position detection deteriorates
Solution Approach 1:
The system transitions from relying on the spatial dimension (narrow detection width) to using the time dimension for achieving precision. Instead of requiring a narrow spatial detection width, the system uses the timing of passage detection through the wider detection width to determine central position. By measuring the time duration or sequence of passage through the detection width boundaries, the system achieves accurate position detection despite the wider spatial detection range, effectively trading spatial precision for temporal measurement.
Data Source
AI summary
A central position detection section has a detection width in which the central position has a median value along one axial direction. When the direction from a position, which is located at the time at which returning is started toward the central position is defined as a go direction, the control section commands that a drive mechanism should sequentially perform following operations: a first operation of driving a projection lens assembly in the go direction; a second operation of allowing the projection lens assembly to travel in a return direction at least by the detection width; and a third operation of allowing the projection lens assembly to travel in the detection width in the go direction by ½ of the detection width traveled in the go direction.