Solid State Image Pickup Device Signal Selection Circuit
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Solution Overview
Problem
Existing solid-state image pickup devices with wider dynamic ranges face challenges in miniaturization due to the need for separate circuits for signal S1 and signal S2, which increases the size and complexity of the device.
Innovation Solution
A solid-state image pickup device with a sensor array and memory that determines whether to use the first signal or the second signal based on a threshold, allowing the same circuit to handle both signals, thereby reducing the device's size and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate circuits are used for signal S1 and signal S2, then the dynamic range is widened, but the device size and complexity increase
Solution Approach 1:
The patent implements a universal circuit architecture where a single set of analog memory circuits (including capacitors and readout circuits) serves both signal S1 and signal S2. The same circuit infrastructure is used for both low-signal and high-signal processing, eliminating the need for separate dedicated circuits for each signal type, thus reducing device complexity while maintaining wide dynamic range capability
Solution Approach 2:
The patent merges the processing paths for signal S1 and signal S2 by using shared analog memory circuits. Both signals are routed through the same memory infrastructure, and the decision to store or overwrite is managed by control logic that determines whether to preserve S1 or replace it with S2, thereby combining what were previously separate circuit paths into a unified system
2Adaptability or versatility
If separate circuits are used for signal S1 and signal S2, then the dynamic range is widened, but the device area increases
Solution Approach 1:
The patent employs universal analog memory circuits that can store both signal S1 and signal S2 sequentially. The same physical memory infrastructure is reused for both signals, eliminating the need for duplicate circuit areas and thereby reducing the overall device footprint while maintaining the capability to handle both low and high signal levels
Solution Approach 2:
The patent implements a nested memory structure where signal S2 is stored in the same analog memory circuits that previously stored signal S1. The memory system is designed to first store S1, then conditionally overwrite with S2 based on signal level comparisons, creating a nested temporal relationship in the same spatial location rather than requiring separate spatial allocations
3Area of stationary object
If the same circuit is used for both signal S1 and signal S2, then the device is miniaturized, but the signal processing complexity increases
Solution Approach 1:
The patent implements preliminary signal level comparison before storage decisions. A comparison circuit evaluates the signal level against a threshold beforehand, and based on this preliminary assessment, control logic determines whether to store S1 or S2 in the analog memory. This preliminary action simplifies the overall processing by making storage decisions before the actual memory write operation, reducing the complexity of the memory management logic
Solution Approach 2:
The patent introduces an intermediary comparison circuit and control logic that mediates between the dual signal paths and the shared memory system. This intermediary layer handles the decision-making process of whether to store S1 or S2, isolating the complexity from the memory circuits themselves and allowing the memory subsystem to remain relatively simple while still achieving intelligent signal management
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 enables miniaturization by allowing the same circuit to function for both signal S1 and signal S2, improving the device's compactness and efficiency while maintaining a wider dynamic range.
Implementation Method 1
the photoelectric charge flowing from the photodiode of each pixel
Data Source
AI summary
The objective of this invention is to provide a solid-state image pickup device and its driving method that has a minimum circuit area and a wide dynamic range. The invention includes: a sensor array SA; a memory M; and a signal determination circuit DC. The sensor array has plural pixels in an array integrated on a semiconductor substrate. Each pixel sequentially outputs a first signal and a second signal. The memory M is connected to each column of pixels array and stores the first signal or the second signal. The signal determination circuit DC outputs signal (SS) such that it works as follows: when the first signal is input to memory M from the pixel, the signal determination circuit DC determines whether the first signal can be used. If so, the first signal is selected and the second signal is discarded and is not output to memory M. When the second signal is selected, the second signal is uploaded to memory M.