Solid-State Image Sensor Readout Speed via Signal Line Reconfiguration
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Solution Overview
Problem
Conventional solid-state image sensors face challenges in increasing readout speed in non-differential mode while maintaining miniaturization, as the number of wired vertical signal lines required for faster readout complicates the design and hinders miniaturization.
Innovation Solution
The solution involves a solid-state image sensor configuration with a connection control unit that manages signal lines to connect pixels to reset power supplies and current sources differently in differential and non-differential modes, allowing for efficient signal amplification and output across multiple signal lines, thereby enhancing readout speed without increasing the number of signal lines.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the number of wired vertical signal lines is increased to double the readout speed, then the readout speed is improved, but the device complexity and miniaturization capability deteriorate
Solution Approach 1:
The patent makes the vertical signal lines VRD and VSL serve multiple functions by switching their connection destinations. In differential mode, they connect to reset power supplies and current sources for sensitivity enhancement. In non-differential mode, they simultaneously function as output signal lines for four pixels, enabling dual-row readout without adding physical lines. This multi-functionality resolves the contradiction between readout speed and device complexity.
Solution Approach 2:
The patent introduces dynamic switching of connection destinations for vertical signal lines based on operating mode. A connection control unit switches between differential mode (connecting to reset power supplies) and non-differential mode (connecting to output terminals), allowing the same physical infrastructure to adapt to different performance requirements. This dynamic reconfiguration enables faster readout when needed without permanently increasing line count.
2Speed
If the number of wired vertical signal lines is increased to double the readout speed, then the readout speed is improved, but the miniaturization capability deteriorates
Solution Approach 1:
The vertical signal lines VRD and VSL are designed to serve dual purposes: they function as power supply lines in differential mode and as output signal lines in non-differential mode. This multi-functionality allows four pixels to share only two output lines, enabling two rows to be read simultaneously without increasing the physical line count or sensor area, thus resolving the contradiction between readout speed and miniaturization.
Solution Approach 2:
The patent merges the functions of multiple signal lines by making VRD and VSL serve both as power supply connections and as output signal paths. By combining these functions into existing lines rather than adding separate lines for each function, the sensor achieves faster readout capability without increasing area, as the same physical infrastructure is utilized more efficiently.
3Measurement precision
If differential amplification is performed, then the sensitivity is improved, but the readout speed deteriorates due to the need for more signal lines
Solution Approach 1:
The patent implements dynamic mode switching that allows the system to transition between differential mode (high sensitivity) and non-differential mode (high speed) based on application requirements. The connection control unit dynamically reconfigures the signal line connections, enabling the sensor to achieve both high sensitivity and high speed performance at different times using the same hardware infrastructure, thus resolving the contradiction between sensitivity and readout speed.
Solution Approach 2:
The vertical signal lines are designed with multi-functionality to support both differential amplification operations and direct output operations. By switching the connection destinations of these lines, the system can perform differential amplification for sensitivity-critical applications or direct output for speed-critical applications, allowing the same hardware to achieve both performance characteristics as needed.
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 configuration effectively increases readout speed in non-differential mode without compromising miniaturization, enabling faster pixel signal processing while maintaining the sensitivity and efficiency of differential mode operations.
Implementation Method 1
each pixel includes a photodiode that photoelectrically converts light to generate an electrical signal
Data Source
AI summary
To increase a readout speed of a pixel signal in a non-differential mode in a solid-state image sensor that performs differential amplification in a differential mode and does not perform differential amplification in the non-differential mode. A connection control unit sequentially performs control of connecting a first pixel connected to a first signal line to a reset power supply via a third signal line and control of connecting a second pixel connected to a second signal line to the reset power supply via a fourth signal line in a differential mode, and performs control of connecting a third pixel to the third signal line and control of connecting the fourth pixel to the fourth signal line in a non-differential mode. Furthermore, a drive unit outputs a signal obtained by amplifying a difference between respective pixel signals of the first and second pixels via one of the first and second signal lines in the differential mode, and outputs respective pixel signals of the first, second, third, and fourth pixels via the first, second, third, and fourth signal lines in the non-differential mode.