Camera Lens Mounting Detection Circuit Design
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Solution Overview
Problem
Existing interchangeable-lens cameras face inefficiencies in determining whether a lens unit is mounted, leading to prolonged determination times and increased risk of erroneous results due to chattering, external noise, and other factors during power-on and lens mounting processes.
Innovation Solution
A camera body design that includes a mounting part with a lens detection terminal connected to a pull-up resistor, a power supply, and a mounting determination part that detects voltage levels at specific intervals to promptly and reliably determine lens unit mounting, using conditional expressions to optimize detection times and intervals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If voltage detection is performed continuously at short intervals to quickly determine lens mounting status, then determination speed is improved, but the risk of erroneous determination increases due to chattering and external noise
Solution Approach 1:
The system performs preliminary voltage detection at a first detection timing with a first time interval before final determination. This preliminary detection filters out transient noise and chattering signals, ensuring that only stable mounting states trigger rapid determination, thus resolving the contradiction between speed and reliability
Solution Approach 2:
The system uses periodic voltage detection at multiple timings (first detection timing with first time interval, second detection timing with second time interval) to continuously monitor the lens mounting state. This periodic monitoring allows the system to distinguish between temporary noise spikes and genuine mounting changes, improving reliability while maintaining responsive determination
2Reliability
If voltage detection is performed at longer time intervals to reduce noise interference, then determination reliability is improved, but determination time increases
Solution Approach 1:
The system dynamically adjusts detection time intervals based on the detection phase: using a first time interval at the first detection timing for preliminary filtering, and a second time interval at the second detection timing for final confirmation. This dynamic adjustment optimizes both reliability and time loss by applying appropriate detection granularity at different stages
Solution Approach 2:
The preliminary detection phase performs initial filtering of noise signals, allowing the final determination phase to use longer time intervals for reliable confirmation without excessive time loss. The preliminary action prepares the system by eliminating obvious false positives, making the subsequent slower detection more efficient
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
Enables rapid and accurate determination of lens unit mounting at power-on and ensures reliable detection post-power-on, reducing the likelihood of errors and improving overall camera operation efficiency.
Implementation Method 1
a lens detection terminal to which a pull-up resistor is connected and which is pulled down while the lens unit is mounted
Implementation Method 2
a mounting determination part determining that the lens unit is mounted on the mounting part if the level of voltage at the lens detection terminal on the mounting part has been detected to be low a plurality of consecutive times
Data Source
AI summary
A main CPU (a mounting determination part) in a camera body makes a determination by detecting voltage, at a lens detection terminal, n1 consecutive times at time intervals of dl, at the time of turning on a power supply with a power switch. After a result of the determination turns out to be non-mounting, the main CPU makes a determination by detecting voltage, at the lens detection terminal, n2 consecutive times at time intervals of d2 (where n2 and d2 are equal to or greater than to n1 and d1, respectively) on condition that any one of conditional expressions d1<d2 and n1<n2 is met.