Image Sensor Cyan Filter and Organic Layer for Blue Sensitivity
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Solution Overview
Problem
Image sensors face reduced sensitivity due to the absorption of wavelengths by color filters, particularly in the blue range, and suffer from cross-talk between pixels, which affects the quality of image processing.
Innovation Solution
The use of a cyan color filter instead of a blue color filter, combined with a red color filter and an organic photoelectric conversion layer that absorbs wavelengths in the green range, along with specific oxide films and a planarization layer, enhances sensitivity to the blue range and reduces cross-talk by optimizing the refractive indices and structural arrangements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a blue color filter is used to transmit blue wavelengths to the photoelectric conversion element, then the photoelectric conversion element can receive blue light, but the color filter itself absorbs a lot of wavelengths in the blue range, reducing sensitivity
Solution Approach 1:
The patent changes the color filter from blue to cyan, fundamentally altering its optical properties. The cyan color filter transmits both blue and green wavelengths, allowing the photoelectric conversion element to receive blue light while reducing absorption losses in the blue range compared to a traditional blue color filter
Solution Approach 2:
The patent employs a composite structure combining cyan color filter, organic photoelectric conversion layer, and multiple oxide films with different refractive indices. This composite material system optimizes light transmission and reduces wavelength absorption, thereby improving sensitivity while maintaining color selectivity
2Measurement precision
If multiple color filters are stacked to improve color selectivity, then wavelength filtering is enhanced, but cross-talk between adjacent pixels increases due to light scattering and diffraction
Solution Approach 1:
The patent applies different refractive index materials (SiO2, SiON, Al2O3) at different locations and depths within the optical path. The oxide films are strategically positioned between the color filter and photoelectric conversion element to locally optimize light transmission while reducing lateral scattering that causes cross-talk between adjacent pixels
Solution Approach 2:
The oxide films with different refractive indices serve as intermediary layers between the cyan color filter and the organic photoelectric conversion layer. These intermediary layers optimize the optical coupling and reduce light scattering, thereby improving color selectivity while minimizing cross-talk between adjacent pixels
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 significantly enhances sensitivity to the blue range while minimizing cross-talk, leading to improved image processing quality.
Implementation Method 1
Each of the pixels includes a photoelectric conversion element that converts incident light into electrical signals
Implementation Method 2
a first oxide film formed on the organic photoelectric conversion layer to have a first refractive index and a second oxide film formed on the first oxide film to have a second refractive index
Data Source
AI summary
An image sensor is provided. The image sensor includes a first photoelectric conversion element and a second photoelectric conversion element, which are formed in a semiconductor substrate; a red color filter formed on the first photoelectric conversion element; a cyan color filter formed on the second photoelectric conversion element; and an organic photoelectric conversion layer formed on the red color filter and the cyan color filter, the organic photoelectric conversion layer configured to absorb wavelengths in a green range.