Image Pickup Apparatus Column Circuit Power Management
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Solution Overview
Problem
Existing image pickup apparatuses that use image plane phase difference detection methods for focus detection increase power consumption and circuit complexity due to the need to read and process multiple signals, leading to inefficiencies in data transmission and processing.
Innovation Solution
An image pickup apparatus with a matrix arrangement of pixels, each containing two photoelectric converters, utilizes a column output line and column circuit to perform selective signal reading and mixing operations, and includes a control unit to save power in unused column circuits during reading operations, optimizing data processing and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple signals (A-image signal and A+B image signal) are read from each pixel for focus detection, then focus detection capability is improved, but power consumption and circuit complexity increase
Solution Approach 1:
The patent implements periodic action by alternately performing a first reading operation (reading A-image signal) and a second reading operation (reading A+B image signal) across different column output lines in a time-division manner. Column circuits are activated periodically for specific reading operations and deactivated during others, enabling focus detection functionality while reducing overall power consumption through rhythmic on-off cycles of circuit operations.
Solution Approach 2:
The patent applies dynamics by making column circuit power states dynamic rather than static. Column circuits are selectively activated or deactivated based on the current reading operation type (first or second reading operation). This dynamic power management allows the system to adapt power consumption to actual operational needs, maintaining focus detection capability while optimizing energy usage.
2Measurement precision
If multiple signals are read and processed for phase difference detection, then focus detection accuracy is improved, but the number of wires and terminals for data transmission increases
Solution Approach 1:
The patent merges the reading operations for A-image signal and A+B image signal into a unified time-division multiplexed framework. Both signals share the same column output lines and column circuits, which are activated at different time periods for different signal types. This merging approach maintains focus detection accuracy by preserving both signal paths while reducing wiring complexity by eliminating the need for completely separate transmission channels.
Solution Approach 2:
The patent resolves the wiring complexity issue by transitioning from a spatial dimension solution (separate parallel wires for each signal) to a temporal dimension solution (time-division multiplexing on shared wires). By adding the time dimension to signal transmission, the system maintains the capability to transmit multiple signals while reducing the number of physical wires and terminals needed.
3Speed
If all column circuits remain active during reading operations, then data reading speed is improved, but power consumption increases
Solution Approach 1:
The patent segments the column circuits into multiple independent groups, each associated with specific column output lines. This segmentation allows selective activation of only the column circuits needed for the current reading operation, rather than keeping all circuits continuously active. Each segment can be independently controlled, enabling efficient power management while maintaining reading speed for the active segments.
Solution Approach 2:
The patent implements periodic action by systematically activating and deactivating column circuit segments in a rhythmic pattern. During the first reading operation, certain column circuits are activated while others are deactivated, and vice versa during the second reading operation. This periodic activation pattern ensures that data reading speed is maintained for active circuits while power consumption is reduced by keeping inactive circuits in low-power states.
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
This approach reduces power consumption and circuit complexity by selectively reading and processing signals, enhancing the efficiency of focus detection while maintaining image quality.
Implementation Method 1
a plurality of pixels each of which includes first and second photoelectric converters
Data Source
AI summary
An image pickup apparatus has a plurality of pixels each of which includes first and second photoelectric converters and is arranged in a matrix and connected to a column output line, a reading unit configured to perform a first reading operation that reads a signal of the first photoelectric converter to the column output line and a second reading operation that reads a signal obtained by mixing the signals of the first and second photoelectric converters to the column output line, a column circuit configured to be connected to the column output line, and a control unit configured to save power in at least some of the column circuits not used during the first reading operation from among the column circuits used in the second reading operation, during the first reading operation.