Image Sensor Common Negative Voltage Power Supply
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Solution Overview
Problem
Conventional image sensors require individual power supplies for each pixel to control exposure time, leading to a reduction in aperture ratio and increased complexity, which complicates the manufacturing process and reduces yield.
Innovation Solution
An image sensor design where a common power supply unit provides a negative voltage to multiple pixels, allowing for control of exposure time through a transfer signal based on either the negative voltage or a positive voltage, eliminating the need for individual power supplies near the photodiode and increasing the fill factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If individual power supplies are provided for each pixel to control exposure time, then exposure time control is achieved, but aperture ratio is reduced
Solution Approach 1:
Multiple pixels share a common negative voltage power supply unit instead of each pixel having its own power supply. This merging of power supply resources eliminates the need for individual negative voltage supplies near each photodiode, thereby increasing the aperture ratio while maintaining exposure time control capability through shared control circuits.
Solution Approach 2:
The common negative voltage power supply unit serves multiple pixels simultaneously, providing universal power supply functionality. The control circuits can selectively apply the negative voltage to different pixels or groups of pixels to achieve individual exposure time control without requiring dedicated power supplies for each pixel.
2Ease of operation
If individual power supplies are provided for each pixel, then exposure time control is achieved, but device complexity increases
Solution Approach 1:
The power supply structure is simplified by merging multiple individual power supplies into a single common negative voltage power supply unit that serves multiple pixels. This reduces the number of power supply components and interconnections, thereby decreasing device complexity and manufacturing difficulty.
3Ease of operation
If individual power supplies are provided for each pixel, then exposure time control is achieved, but manufacturing yield is reduced
Solution Approach 1:
By consolidating power supply resources into a common unit, the number of fabrication steps and quality control checkpoints is reduced. This merging approach simplifies the manufacturing process and improves yield by eliminating the need to individually test and validate power supply connections for each pixel.
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 design allows for parallel reading of pixels without individual negative voltage supplies, increasing the fill factor and enabling miniaturization of the image sensor while maintaining control over exposure time for each pixel.
Implementation Method 1
a photoelectric conversion unit that photoelectrically converts incident light
Data Source
AI summary
An image sensor includes: (1) a first pixel and a second pixel each including: a photoelectric conversion unit that photoelectrically converts light and generates an electric charge; and a transfer unit that transfers the electric charge generated by the photoelectric conversion unit to an accumulation unit that accumulates the electric charge, the first pixel and the second pixel being arranged in a row direction; (2) a first supply unit that supplies a signal which controls the transfer unit of the first pixel; and (3) a second supply unit that supplies a signal which controls the transfer unit of the second pixel.