Digital Camera Movable Mirror Control for Live View Autofocus
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Solution Overview
Problem
Digital single-lens reflex cameras with live view mode have insufficient operability in switching the movable mirror, making it difficult for users to capture images while observing through an optical viewfinder.
Innovation Solution
The camera is equipped with an image pickup element, a display portion, a distance-measuring portion, an autofocus portion, and a control portion that allows the movable mirror to enter or retract from the optical path, enabling real-time display of image data on an electronic viewfinder and simplifying autofocus and image capture operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the movable mirror is switched frequently in live view mode for autofocus and image capture operations, then the camera can perform both optical viewfinding and live view display, but the operability becomes complex and time-consuming for the user
Solution Approach 1:
The control portion automatically manages the movable mirror switching based on detected operation types. When autofocus operation is detected in live view mode, the system automatically switches the movable mirror to the optical path position and then returns it to the live view position, without requiring manual user intervention for each switching action.
Solution Approach 2:
The system detects the type of operation being performed (autofocus, image capture, or live view display) and uses this feedback to automatically control the movable mirror position. The control portion monitors operation states and adjusts the mirror position accordingly, creating a closed-loop control system that responds to operational context.
2Reliability
If manual manipulation is required to switch the movable mirror for each operation, then the camera can maintain precise control over the optical path, but the user experiences time loss and operational complexity
Solution Approach 1:
The control portion is pre-programmed with the sequence of mirror positioning actions required for different operations. When an operation type is detected, the system automatically executes the pre-determined sequence of mirror switching actions, eliminating the need for users to manually perform each switching step and reducing overall operation time.
Solution Approach 2:
The system performs the mirror switching operations automatically based on detected operation types, serving itself by managing the optical path control without requiring continuous user intervention. This maintains precise control while significantly reducing the time users spend on manual switching operations.
3Measurement precision
If the movable mirror remains in the optical path during live view mode, then autofocus measurement can be performed, but the live view display is interrupted and user confusion increases
Solution Approach 1:
The movable mirror is switched to the optical path position only periodically when autofocus operation is detected, rather than remaining there continuously. After completing the autofocus measurement, the mirror returns to its original position for live view display. This periodic switching maintains measurement capability while preserving live view continuity and reducing user confusion.
Solution Approach 2:
The control portion detects when autofocus operation is required and uses this feedback to temporarily switch the mirror position, then automatically returns it afterward. This feedback-driven control ensures the mirror is in the correct position only when needed for measurement, maintaining both measurement precision and operational clarity.
Data Source
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AI summary
A digital camera of the present invention includes a microcomputer 110 having a live view mode controlling so that image data generated by a CMOS sensor 130 or image data obtained by subjecting the image data generated by the CMOS sensor 130 to predetermined processing is displayed on a liquid crystal monitor 150 as a moving image in real time, wherein when a release button 141 receives an instruction regarding start of an autofocus operation in a live view mode, the microcomputer 110 controls a movable mirror to enter an optical path to measure by an AF sensor 132, and thereafter, allow the movable mirror to retract from the optical path to return the digital camera to the live view mode. Due to this configuration, in a digital camera that includes a movable mirror and is capable of displaying a subject image in a live view through an electronic viewfinder, the operability thereof can be enhanced.