Optical Sensing Units With Differential Channel Widths
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Solution Overview
Problem
Conventional optical sensing modules face challenges in increasing sensitivity to accurately determine the region receiving light due to current leakage and voltage variations across multiple optical sensing units connected to the same reading lines.
Innovation Solution
The optical sensing module incorporates a plurality of optical sensing units with different channel widths for transistors and gate-to-source voltages, coupled with differential amplifiers to compute voltage differences between reading lines, enhancing the detection of ambient light variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If multiple optical sensing units share the same reading lines, then device complexity is reduced, but measurement precision deteriorates due to current leakage and voltage variations
Solution Approach 1:
The patent applies local quality by assigning different characteristic values (different channel widths) to different optical sensing units. Specifically, optical sensing units in different regions (e.g., first region vs. second region) have transistors with different channel widths, which compensates for the voltage variations and current leakage effects that occur when multiple units share reading lines. This localized differentiation maintains measurement precision while allowing shared reading line architecture.
Solution Approach 2:
The patent changes the parameter of transistor channel width to resolve the contradiction. By varying the channel width parameter across different optical sensing units based on their spatial location, the system compensates for the voltage drops and current leakage that occur in shared reading line configurations. This parameter adjustment allows multiple sensing units to share reading lines while maintaining adequate measurement precision.
2Manufacturing precision
If optical sensing units have uniform characteristics, then manufacturing precision is improved, but sensitivity to detect light variations deteriorates
Solution Approach 1:
The patent implements local quality by making different regions of the optical sensing module have different transistor characteristics. Specifically, optical sensing units in different spatial regions have different channel widths, which creates enhanced sensitivity to light variations across different areas of the module. This localized differentiation improves measurement precision while maintaining manufacturability through systematic design.
Solution Approach 2:
The patent applies asymmetry by intentionally creating non-uniform transistor characteristics across different optical sensing units. Instead of uniform channel widths, the design uses asymmetric channel width assignments based on spatial location, which enhances the ability to detect and differentiate light variations across different regions of the sensing module.
3Device complexity
If all optical sensing units use the same channel width, then device complexity is reduced, but the ability to determine light exposure region accurately deteriorates
Solution Approach 1:
The patent applies local quality by assigning different channel widths to optical sensing units in different spatial regions. This localized differentiation creates distinct voltage response characteristics for different regions, enabling accurate determination of which specific region received light exposure. The different channel widths act as regional identifiers that preserve spatial information.
Solution Approach 2:
The patent changes the channel width parameter across different optical sensing units to encode spatial information. By varying this parameter based on location, the system maintains the ability to accurately identify which region received light exposure, preventing loss of spatial information while keeping the overall device architecture relatively simple.
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 improves the sensitivity and accuracy of detecting light variations by providing a more obvious voltage difference, allowing for precise localization of light exposure across the module.
Implementation Method 1
When the optical sensing unit is exposed to light, the cross voltage Va is decreased owing to the current leakage according to the strength of light
Implementation Method 2
The channel width of the first transistor in the sensing unit of the first optical sensing unit is different from the channel width of the first transistor in the sensing unit of the second optical sensing unit
Data Source
AI summary
An optical sensing device includes a plurality of scanning lines having a plurality of first scanning lines and a plurality of second scanning lines, a plurality of sensing lines, a plurality of reading lines, and a plurality of optical sensing modules electrically connected to the scanning lines. Each optical sensing module includes a first optical sensing unit and a second optical sensing unit, each of which includes a sensing unit, a charge storage unit, and a reading unit. The optical sensing module further includes a plurality of differential amplifiers electrically connected to the corresponding reading lines, for determining the difference between the reading lines, wherein the difference indicates the ambient light variation. A first transistor of the sensing unit of the first optical sensing unit is different to a first transistor of the sensing unit of the second sensing unit in channel width.