Transparent Image Sensor Layout With Cross-Patterned Photodetectors
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Solution Overview
Problem
Existing image acquisition devices based on organic photodetectors face challenges in maximizing surface area for photodetectors while maintaining transparency and sensitivity, particularly when integrated with display screens, as opaque layers and optical filters reduce visibility and sensitivity.
Innovation Solution
The image acquisition device features photodetectors patterned along lines of interconnection with cross-patterned electrodes and a common grid-patterned hole injection layer, where the active layer and electrodes extend beyond the pattern, minimizing opaque surface coverage to less than 50% of the pixel area, allowing for increased transparency and sensitivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the surface area of photodetectors is increased to improve sensitivity, then sensitivity is improved, but transparency deteriorates due to increased opaque coverage
Solution Approach 1:
The photodetector active layer is segmented into multiple discrete regions arranged along the interconnection lines, rather than forming a continuous opaque layer. This segmentation allows light to pass through the gaps between segments, maintaining transparency while each segment still contributes to sensitivity. The cross-pattern configuration divides the active area into four quadrants that are spatially separated.
Solution Approach 2:
The patent transitions from a traditional planar photodetector layout to a three-dimensional stacked architecture where the active layer is positioned above the interconnection lines in the vertical dimension. This allows the photodetector to utilize the vertical space above the transparent substrate without blocking the horizontal light path, enabling both high sensitivity and transparency.
2Measurement precision
If opaque layers and optical filters are added to improve image acquisition performance, then sensitivity and resolution are improved, but transparency deteriorates
Solution Approach 1:
Optical filters are applied selectively only to the photodetector active regions rather than covering the entire device surface. This localized application ensures that filtering functionality is provided where needed for image acquisition while leaving the surrounding areas transparent. The filters are integrated into the stacked architecture at specific vertical positions above the interconnection lines.
3Adaptability or versatility
If photodetectors are integrated with display screens, then functionality is improved, but transparency deteriorates due to additional layers
Solution Approach 1:
The image acquisition device and display screen are merged into a single integrated stacked structure where the photodetector active layer, interconnection lines, and display elements are vertically aligned. This merging allows both functions to coexist in a compact form factor while maintaining transparency by utilizing the vertical dimension rather than adding horizontal layers that would block light.
4Illumination intensity
If the active layer and electrodes are confined to a small pattern area, then transparency is improved, but sensitivity deteriorates
Solution Approach 1:
The active layer and electrode structures extend continuously beyond the immediate pattern area into the regions above the interconnection lines. This continuous extension ensures that the photodetector functionality is maintained across the entire pixel area while keeping the patterned regions compact. The active material forms a continuous film that captures photons throughout the available space without creating discrete isolated islands.
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 enhances the overall transparency of the device without compromising sensitivity or resolution, allowing for a better trade-off between transparency and performance, as demonstrated by achieving high transparency rates such as 70% with specific pixel dimensions.
Implementation Method 1
image acquisition devices based on organic photodetectors
Data Source
Figure 1~2
Figure 3
Figure 4A~4C
AI summary
The present description relates to an image acquisition device (1), in which photodetectors (2) have a pattern following lines (14, 16) of interconnection of reading circuits (3) and the first electrodes (27) of the photodetectors (2) have a cross pattern (57) of which two branches are respectively in line with the lines (14, 16) interconnecting the reading circuits (3).