Active Pixel Sensor Array Element Reduction
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Solution Overview
Problem
Active pixel image sensors require a large number of elements and capacitors, which hinders high-resolution imaging due to signal-to-noise ratio degradation and increased size requirements.
Innovation Solution
Incorporating a reset switching transistor with optical sensor functionality, allowing it to reset pixel voltage to power supply voltage VDD using a coupling function between capacitors, reducing the number of elements and capacitor size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large number of elements and capacitors are used in active pixel image sensors, then the signal-to-noise ratio is improved, but the device size increases and manufacturing complexity increases
Solution Approach 1:
The patent combines the reset switching transistor and optical sensor into a single integrated structure. The reset switching transistor serves dual functions: as a switching element for resetting pixel voltage and as an optical sensor for detecting light. This merging reduces the total number of elements in the pixel array while maintaining signal-to-noise ratio performance.
Solution Approach 2:
The reset switching transistor is designed to perform multiple functions: it acts as both a switching transistor for voltage reset and an optical sensor for light detection. This multi-functionality eliminates the need for separate optical sensor elements, thereby reducing device complexity and element count while preserving imaging capabilities.
2Reliability
If high capacity storage capacitors are used to improve signal-to-noise ratio, then the signal-to-noise ratio is improved, but the capacitor size increases
Solution Approach 1:
The patent eliminates the need for large storage capacitors by merging the optical sensor function into the reset switching transistor. The integrated structure inherently provides sufficient signal-to-noise ratio performance without requiring additional large-capacity storage capacitors, thus reducing the area occupied by capacitive elements in each pixel.
3Manufacturing precision
If additional optical sensors are added to improve imaging capability, then the imaging quality is improved, but the number of elements and device complexity increases
Solution Approach 1:
The reset switching transistor is designed to serve as both a switching element and an optical sensor. By making the switching transistor itself sensitive to light, the patent eliminates the need for separate optical sensor elements while maintaining imaging quality. This approach reduces device complexity and element count.
Solution Approach 2:
The reset switching transistor performs self-service by detecting light signals while performing its switching function. The transistor's own structure is utilized for optical detection, eliminating the need for external or additional optical sensing elements. This self-service approach reduces overall device complexity while maintaining imaging capabilities.
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
Enables efficient reduction in the number of elements and capacitor size, enhancing the capability to produce high-resolution images without the need for additional optical sensors or electrodes.
Implementation Method 1
resetting a pixel voltage to be lower than the power supply voltage VDD by a coupling function of capacitors when the gate selection signal is outputted
Implementation Method 2
an optical sensor array 1 composed of pixels 2 for converting the strength of the light into a quantity of electric charge
Data Source
AI summary
Disclosed is an active pixel sensor array, which can reduce the number of elements and the size of capacitors by enabling a reset switching transistor to include a function of an optical sensor and to reset a pixel voltage with a power supply voltage VDD after a gate selection signal is outputted, and to reset a pixel voltage with a power supply voltage VDD by a coupling function in case that a gate selection signal is outputted. The active pixel image sensor having a gate driving circuit and a column driving circuit includes a pixel composed of a voltage supply unit for supplying a signal voltage to the column driving circuit; a gate selection unit for turning on according to a n+1-th gate selection signal and outputting a voltage based on a difference between a pixel voltage and a threshold voltage of the voltage supply unit; a reset switching unit for turning on according to a n+1-th gate selection signal and resetting the pixel voltage with a power supply voltage VDD; and a storage unit and a coupling unit for coupling so as to initialize the pixel voltage to be lower than the power supply voltage VDD just after the n+1-th gate selection signal is outputted.