Focus Control Device Reducing Lens Drive Wear
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Solution Overview
Problem
The frequent automatic focus operations in monitoring cameras lead to increased wear of components in the focus lens driving mechanism, reducing durability and reliability due to continuous operation and sensitivity to changes in brightness.
Innovation Solution
A focus control system that detects changes in focus status and only initiates automatic focus adjustments after a predetermined waiting period if the change is sustained, reducing the frequency of focus lens driving operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If automatic focus operation is performed immediately upon detecting not-in-focus state, then recovery to in-focus state is achieved quickly, but mechanical wear of driving mechanism increases
Solution Approach 1:
The patent applies periodic action by introducing a waiting time period between automatic focus operations. The drive control unit waits for a predetermined time after detecting a focus status change before initiating another focus operation, thereby converting continuous rapid operations into periodic spaced operations. This reduces mechanical wear while maintaining acceptable focus recovery performance.
2Stability of the object's composition
If automatic focus operation frequency is increased to maintain in-focus state during continuous operation, then image quality stability is improved, but mechanical wear of driving mechanism increases
Solution Approach 1:
The patent implements periodic action by establishing a waiting time mechanism that spaces out automatic focus operations. The drive control unit does not immediately restart focus operations after a waiting time period elapses, thereby reducing the frequency of mechanical operations while still maintaining image quality stability through periodic focus checks and adjustments.
3Adaptability or versatility
If focus lens driving mechanism operates continuously to respond to brightness changes, then adaptability to environmental changes is improved, but mechanical wear increases
Solution Approach 1:
The patent applies periodic action by introducing a waiting time period that limits the frequency of focus operations in response to brightness changes. The drive control unit waits for a predetermined time after detecting brightness-induced focus status changes before initiating another operation, thereby reducing mechanical wear while maintaining adequate adaptability to environmental variations.
Data Source
AI summary
A focus control device includes a lens unit including a focus lens; a focus lens driving mechanism that moves the focus lens to achieve an in-focus state; a focus status detector that detects a focus status acquired by the focus lens; a drive control unit that controls the focus lens driving mechanism so that the detected focus status is the in-focus state; a change detector that detects that an evaluation value for focus control has changed by a threshold value or more; and an execution control unit that waits in a state in which the drive control unit does not control the focus lens driving mechanism for a waiting time starting from a time when the change detector detects that the evaluation value has changed by the predetermined threshold value or more, and that causes the drive control unit to control the focus lens driving mechanism when the state in which the evaluation value has changed by the predetermined threshold value or more is maintained until the waiting time has elapsed.