Projector Lens Replacement Detection via Positional Comparison
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Solution Overview
Problem
Existing projectors cannot accurately detect the replacement of a projection lens when the lens type ID remains the same before and after replacement, leading to potential errors in lens calibration.
Innovation Solution
A method is introduced where the projector determines lens replacement by comparing the position of the projection lens at a first time point when power is stopped to its position at a second time point when power is resumed, allowing for detection even if the lens type IDs are the same, and includes a threshold for positional differences to minimize false positives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the projector determines lens replacement using lens type ID comparison, then the determination method is simple, but it cannot detect replacement when lens type ID remains the same
Solution Approach 1:
The determination section divides the lens identification into multiple segments: first comparing lens type ID, then comparing positional information when type IDs match. This segmentation allows the system to maintain simple initial screening while adding detailed verification only when necessary, resolving the contradiction between simplicity and accuracy.
Solution Approach 2:
The system performs preliminary comparison of lens type ID before conducting the more detailed positional information comparison. This preliminary action filters out most cases where replacement is clearly indicated by type ID changes, reserving the more complex positional analysis for cases where type IDs are identical, thus maintaining efficiency while improving accuracy.
2Measurement precision
If the projector performs lens calibration frequently to ensure accuracy, then measurement precision improves, but loss of time increases
Solution Approach 1:
The determination section uses feedback from lens position sensor comparisons to decide whether calibration is needed. By continuously monitoring position changes and comparing them against threshold values, the system only triggers calibration when actual replacement is detected, avoiding unnecessary calibration operations and reducing time loss while maintaining measurement precision.
Solution Approach 2:
The system changes the parameter being monitored from lens type ID alone to a combination of lens type ID and positional information. This parameter change enables more accurate detection of actual replacements versus temporary position changes, reducing false positives and minimizing unnecessary calibration interruptions.
3Duration of action of moving object
If the projector uses sensor output to determine lens position, then measurement is continuous, but individual sensor variations cause correspondence errors
Solution Approach 1:
The determination section performs an excessive verification by comparing both lens type ID and positional information before confirming replacement. This partial redundancy ensures that temporary sensor variations or position fluctuations during operation do not trigger false replacement detection, maintaining continuous monitoring accuracy while compensating for sensor individual variations.
Data Source
AI summary
A projector includes a drive section adapted to move a projection lens, a projection section adapted to project image light through the projection lens, and a determination section adapted to determine whether or not the projection lens has been replaced based on a first position as a position of the projection lens at a first time point at which power supply to the projector is stopped, and a second position as a position of the projection lens at a second time point at which the power supply is started after the first time point.