Lens Driving Apparatus Dynamic Pulse Control for Focusing Precision
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Solution Overview
Problem
Conventional lens driving apparatuses fail to simultaneously achieve quick and precise lens positioning due to uneven resolving power with respect to lens drive pulses, particularly on the short and long distance sides, leading to difficulties in focusing.
Innovation Solution
A lens driving apparatus and method that includes a signal detection unit, a lens driving unit, and a control unit to adjust the drive signal based on detected signals, varying the lens driving amount between an initial detection time period and subsequent periods, and adjusting the number of drive pulses according to the lens position to optimize focusing speed and precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the number of drive pulses is increased to achieve precise focusing on the short distance side, then the manufacturing precision is improved, but the productivity deteriorates due to the large number of pulses required
Solution Approach 1:
The patent applies dynamics by making the lens driving amount dynamic based on the detection signal state. The control unit changes the lens driving amount according to whether the detection signal is in an initial state or a subsequent state, allowing the system to adaptively adjust between precision and speed requirements at different focusing stages
Solution Approach 2:
The patent changes the parameter of lens driving amount based on the detection signal. By varying the lens driving amount according to the initial detection time period versus subsequent periods, the system optimizes both focusing precision and speed for different distance ranges
2Productivity
If the lens driving amount is increased to achieve quick focusing on the long distance side, then the productivity is improved, but the manufacturing precision deteriorates due to the large variation of in-focus position per pulse
Solution Approach 1:
The control unit dynamically adjusts the lens driving amount based on the detection signal state. For initial detection signals, a smaller lens driving amount is applied to ensure precision, while for subsequent signals, a larger driving amount is used to improve focusing speed
Solution Approach 2:
The patent varies the lens driving amount parameter according to the timing of the detection signal. This parameter change allows the system to achieve both quick focusing and precise positioning by adapting the driving amount to the specific operational context
3Device complexity
If a fixed lens driving amount is used for all detection signals, then the device complexity is reduced, but the adaptability deteriorates because the control cannot follow the variation of in-focus position
Solution Approach 1:
The patent applies local quality by providing different lens driving amounts for different stages of the detection signal. The initial detection time period receives a different driving amount compared to subsequent periods, allowing localized optimization for precision and speed requirements at different operational stages
Data Source
AI summary
A lens driving apparatus and a lens driving method are capable of quickly and precisely setting the position of a lens to a predetermined position, if the resolving power of the amount of lens moving according to drive pulses is not even in the lens driving apparatus. A count pulse signal detection unit detects a count pulse signal CP in accordance with a rotation of a manual focus (MF) ring. A lens driving control unit outputs a drive pulse MP for moving a focus lens in correspondence with the detected count pulse signal CP to a lens driving unit. The lens driving control unit performs a control so that: the number of the drive pulses MP for a count period T differs between a time period within an initial count detection time period for the detected count pulse signal CP and a time period after the initial count signal detection time period; and the number of pulses for the former period is minimum and the number of pulses for the latter period is larger than the minimum number.