Stacked Perovskite Image Sensor Eliminates Color Filters
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Solution Overview
Problem
Conventional CMOS image sensors face limitations in signal-to-noise ratio and dynamic range due to the area occupied by active circuitry, which reduces quantum efficiency and fill factor, and the use of color filter arrays can decrease image sensor resolution.
Innovation Solution
The implementation of a stacked structure using four Perovskite material layers for sensing blue, green, red, and infrared light, respectively, which omits the need for a color filter array, allowing for higher resolution and signal-to-noise ratio by utilizing spectral region-selective Perovskite films and charge transport layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a color filter array is used for wavelength separation, then color sensing capability is improved, but image sensor resolution decreases
Solution Approach 1:
The patent transitions from a planar color filter array arrangement to a three-dimensional stacked architecture where multiple photosensitive layers are vertically arranged. Each layer is specialized for detecting specific wavelength ranges (blue, green, red, infrared), enabling spectral separation through vertical stacking rather than horizontal filtering, thereby maintaining high spatial resolution while achieving comprehensive color sensing capability.
Solution Approach 2:
The image sensor is segmented into multiple functionally specialized photosensitive layers, with each layer dedicated to detecting a specific wavelength range. This segmentation allows each layer to be optimized for its specific function without the need for color filters, improving both resolution and spectral discrimination capability.
2Ease of manufacture
If pixel dimensions are shrunk to reduce cost, then manufacturing cost decreases, but signal-to-noise ratio and dynamic range become limited
Solution Approach 1:
The patent employs Perovskite materials which exhibit superior optical absorption properties compared to conventional silicon. This material parameter change enables the photosensitive layers to achieve high quantum efficiency and signal-to-noise ratio even when the pixel dimensions are reduced, allowing cost-effective manufacturing without sacrificing performance.
Solution Approach 2:
The use of Perovskite material, a composite crystal structure with specific optical properties, provides enhanced light absorption and charge carrier generation. This material choice allows smaller pixels to maintain high sensitivity and low noise performance, resolving the contradiction between miniaturization and signal quality.
3Manufacturing precision
If active circuitry area is reduced to improve fill factor, then quantum efficiency is improved, but device functionality is compromised
Solution Approach 1:
By stacking multiple photosensitive layers vertically, the patent moves the spectral separation function from the lateral dimension (where it would compete with circuitry space) to the vertical dimension. This allows each layer to be dedicated to light sensing with minimal active circuitry, maximizing fill factor while maintaining full color and infrared sensing functionality.
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 approach enables up to three times higher pixel resolution and reduced manufacturing costs by simplifying the process and eliminating the need for additional color filters, while the Perovskite material's high absorption coefficient enhances sensitivity across specific light wave ranges.
Implementation Method 1
a first photosensitive layer for sensing blue light; a second photosensitive layer for sensing green light; a third photosensitive layer for sensing red light; and a fourth photosensitive layer for sensing infrared light, wherein the first, second, third and fourth photosensitive layer are stacked on each other and each comprise a Perovskite material
Implementation Method 2
image sensors are known, which are typically semiconductor devices that convert an optical image (i.e. incident (image) light) into an electric signal
Data Source
AI summary
The present disclosure pertains to an image sensor, including: a first photosensitive layer (2) for sensing blue light; a second photosensitive layer (3) for sensing green light; a third photosensitive layer (4) for sensing red light; and a fourth photosensitive layer (5) for sensing infrared light, wherein the first, second, third and fourth photosensitive layer are stacked on each other and each comprise a Perovskite material.