Projection Device Auto-Focus Lookup Table Update
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Solution Overview
Problem
Existing projection devices face challenges in achieving optimal auto-focus effects due to non-linear relationships between projection distance and motor position, which are not perfectly captured with a limited number of samples, leading to compromised image clarity and the need for manual focus adjustments.
Innovation Solution
A projection device equipped with a distance detector, motor, driving circuit, and control unit that updates an expanded look-up table based on manual-focus operations, allowing for continuous optimization of the relationship between projection distance and motor steps, thereby enhancing auto-focus performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If more samples of motor positions are collected to improve the accuracy of the relationship curve between projection distances and motor positions, then the auto-focus effect is improved, but the production time and labor hours increase significantly
Solution Approach 1:
The patent applies preliminary action by pre-collecting motor position samples at multiple predetermined projection distances during the manufacturing process and storing them in a look-up table. This allows the system to have accurate focus data ready in advance without requiring extensive real-time measurements, thus improving the accuracy of the relationship curve while controlling production time.
Solution Approach 2:
The patent uses partial action by collecting motor position samples at specific predetermined projection distances (e.g., 2m, 3m, 4m, 5m) rather than attempting to measure all possible distances. This selective sampling approach provides sufficient accuracy for the relationship curve without the excessive time investment required for comprehensive measurements across all possible distances.
2Productivity
If interpolation is used to calculate motor position for focus operation to reduce production time, then the production efficiency is improved, but the clarity of the auto-focus image is compromised
Solution Approach 1:
The patent applies preliminary action by pre-measuring and storing accurate motor position data at multiple predetermined projection distances in a look-up table during manufacturing. When auto-focus is needed, the system directly retrieves the pre-measured data corresponding to the detected projection distance, eliminating the need for interpolation calculations and ensuring high image clarity while maintaining production efficiency.
3Ease of operation
If default settings of projection distance and motor position are used to simplify operation, then the ease of operation is improved, but the focusing effect deteriorates over time due to wear of motor parts
Solution Approach 1:
The patent applies feedback by implementing a look-up table that stores corresponding relationships between projection distances and motor positions. The system detects the current projection distance, queries the look-up table for the appropriate motor position, and automatically adjusts the lens accordingly. This closed-loop approach maintains reliable focusing effects over time by adapting to actual device conditions while keeping the operation simple for users.
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 solution enhances auto-focus effects by continuously updating the look-up table, improving convenience and maintaining optimal performance even with wear of motor parts or decline in distance sensor performance.
Implementation Method 1
the distance detector detects a projection distance between the projection lens and the projection surface to generate a distance detection signal
Data Source
AI summary
A projection device and an auto-focus method of the projection device are provided. A projection distance between a projection lens of the projection device and a projection surface is detected to generate a distance detection signal. A control unit updates an expanded look-up table based on the original look-up table, the distance detection signal, an optimal motor step, and an adjustment completion time, where the optimal motor step and the adjustment completion time are obtained through a manual focus operation. An auto-focus operation is performed based on the distance detection signal and the updated expanded look-up table.