Lens Actuator Drive Switching for Noise and Power Control
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Solution Overview
Problem
Existing image pickup apparatuses face challenges in balancing noise reduction with power efficiency due to the use of pulse width modulation (PWM) control for actuators, which results in reduced image capture numbers.
Innovation Solution
A control apparatus that switches between PWM and linear output methods for actuators based on power requirements, using a power circuit to optimize power supply to driver ICs, thereby maintaining power efficiency while reducing noise.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If PWM control is used to drive the actuator, then power efficiency is improved, but noise is generated that affects image quality
Solution Approach 1:
The patent dynamically switches between PWM control and linear control methods based on operational conditions. The control unit selects PWM control for normal operation to maximize power efficiency, and switches to linear control when noise suppression is required, such as during image stabilization operations. This dynamic adaptation resolves the contradiction by allowing the system to optimize for power efficiency when possible while suppressing noise when image quality is paramount.
Solution Approach 2:
The patent changes the control parameter from PWM duty cycle modulation to linear voltage/current modulation when noise suppression is needed. By altering the fundamental control method's parameter approach, the system can eliminate PWM-related noise while maintaining actuator drive capability. This parameter change allows the system to transition between the two control modes effectively.
2Object-generated harmful factors
If linear control is used to drive the actuator, then noise is suppressed, but power efficiency deteriorates
Solution Approach 1:
The control unit dynamically determines when to apply linear control by monitoring operational conditions. Linear control is activated only when noise suppression is required (such as during image stabilization), and deactivated when PWM control can be used, thereby minimizing the impact on power efficiency. This dynamic switching strategy ensures that linear control's noise suppression benefit is realized without permanently sacrificing power efficiency.
Solution Approach 2:
The system periodically evaluates whether to switch between control modes based on current operational requirements. By implementing periodic assessment of noise sensitivity and power consumption conditions, the system can intelligently transition between PWM and linear control, ensuring that linear control is applied only when necessary for noise suppression while maintaining overall system power efficiency.
3Use of energy by moving object
If PWM control is used, then power efficiency is improved, but the number of capturable images is reduced
Solution Approach 1:
The control unit dynamically switches control modes based on the specific operational context. During continuous image capture sequences where power efficiency is critical, PWM control is used. When image stabilization or other noise-sensitive operations are required, the system transitions to linear control. This dynamic adaptation allows the system to maintain high productivity by using PWM control for the majority of operations while enabling linear control when necessary for image quality.
Solution Approach 2:
The system changes control parameters adaptively based on operational requirements. By monitoring the type of operation being performed (e.g., autofocus vs. image stabilization), the control unit adjusts the control method parameter, selecting PWM for power-efficient operations and linear control for noise-sensitive operations. This parameter change strategy maximizes both productivity and image quality according to contextual needs.
Data Source
AI summary
A control apparatus for a camera system that includes an image pickup apparatus and a lens apparatus including a driven unit, an output unit that is supplied with power from the image pickup apparatus, an actuator configured to move the driven unit includes a driving unit configured to drive the actuator by a PWM output method or a linear output method using the power from the output unit, and a control unit configured to control an output of the power from the output unit to the driven unit. The control unit causes the output unit to output a first power in a case where the driving unit drives the actuator by the PWM output method, and in a case where the driving unit drives the actuator by the linear output method, the control unit causes the output unit to output a second power different from the first power.