Solid-State Imaging Device Pixel Unit Dynamic Range Expansion
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Solution Overview
Problem
Conventional solid-state imaging devices have a limited dynamic range of approximately 60 dB to 80 dB, which is insufficient for high-performance applications like vehicle-mounted or monitoring cameras, and existing techniques require external storage and signal combining units, leading to increased processing time and complexity.
Innovation Solution
A solid-state imaging device with two-dimensionally arranged pixel units, including a light-receiving element, a transferring unit, a charge combining unit, a storing unit, and a voltage setting unit, which allows for sequential transfer and combination of optical signal charges without external storage or combining units, expanding the dynamic range by integrating these functions within the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If signals are stored separately for different exposure times, then dynamic range expansion is achieved, but processing time increases and external storage units are required
Solution Approach 1:
The patent merges the storing unit and charge combining unit functions directly into the pixel unit, eliminating the need for external storage and combining units. This integration allows signals from different exposure times to be combined within the pixel itself, reducing processing time while achieving dynamic range expansion.
Solution Approach 2:
The pixel unit is designed to perform multiple functions: it acts as both the light-receiving element and the charge combining unit. The same pixel structure handles both signal generation and signal combination for different exposure times, eliminating the need for separate external processing units.
2Adaptability or versatility
If external storage and signal combining units are used, then dynamic range is expanded, but device complexity increases
Solution Approach 1:
The patent combines multiple functions (light reception, charge storage, and signal combination) into a single integrated pixel unit structure. This eliminates the need for separate external storage units and combining units, thereby reducing overall device complexity while maintaining dynamic range expansion capability.
Solution Approach 2:
The pixel unit serves multiple purposes: it generates optical signal charges, stores them temporarily, and combines signals from different exposure times. This multi-functionality eliminates the need for additional dedicated components, reducing device complexity.
3Adaptability or versatility
If multiple exposure time frames are captured and combined, then dynamic range is improved, but processing complexity increases
Solution Approach 1:
The patent merges the charge combining function directly into the pixel unit, allowing signals from multiple exposure time frames to be combined within the pixel itself. This integration simplifies the processing architecture by eliminating separate combining units and reducing the complexity of signal processing operations.
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
The solution enables the expansion of the dynamic range without external charge combining units, reducing processing time and complexity, and improving sensitivity and area efficiency, allowing for higher definition images in various camera applications.
Implementation Method 1
a light-receiving element that generates an optical signal charge corresponding to an intensity and an exposure time of light entering the light-receiving element
Data Source
AI summary
Provided is a solid-state imaging device having pixel units that are two-dimensionally arranged, and including: a photodiode that generates an optical signal charge corresponding to an intensity and an exposure time of light; a MOS transistor that transfers the optical signal charge; an accumulating unit that generates a voltage corresponding to the signal charge through the MOS transistor; a storing unit that stores a voltage corresponding to an optical signal charge in the accumulating unit; and a voltage setting unit that sets a value of a voltage in the accumulating unit to a value corresponding to the voltage in the storing unit.