Dual-Layer Imaging Sensor Light Efficiency
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Solution Overview
Problem
Conventional image sensors with color filters have poor light use efficiency as light other than the intended color is absorbed or reflected, leading to suboptimal utilization of incident light.
Innovation Solution
The imaging device employs a dual-layer photoelectric conversion system where the upper layer absorbs specific color components and transmits other components to a lower layer for conversion, allowing all visible light to be utilized, and an image processing unit generates color image signals by combining outputs from both layers, enhancing light use efficiency and signal quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If color filters are used in each pixel to capture specific color components, then color image quality is improved, but light use efficiency deteriorates because light other than the intended color is absorbed or reflected
Solution Approach 1:
The image sensor is segmented into two separate layers: an upper photoelectric conversion layer with color filters for capturing color information, and a lower photoelectric conversion layer without color filters for capturing total light intensity. This segmentation allows each layer to perform its specialized function, resolving the contradiction between color quality and light efficiency.
Solution Approach 2:
The invention transitions from a single-plane color filter array to a three-dimensional stacked architecture with multiple photoelectric conversion layers. By adding the vertical dimension, the system can simultaneously process different spectral components through different layers, achieving both color accuracy and high light efficiency.
2Loss of information
If color filters are placed in front of each pixel, then spectral separation is improved, but overall light utilization deteriorates as significant portions of incident light are absorbed or reflected
Solution Approach 1:
The lower photoelectric conversion layer serves as a universal receiver that captures all wavelengths of light that pass through the upper layer, complementing the specialized color-filtered pixels above. This multi-functional approach ensures that no light is wasted, as each photon is utilized by at least one pixel type.
Solution Approach 2:
Instead of discarding the light that passes through the color filters in the upper layer, the invention recovers this transmitted light in the lower layer. The lower layer captures the remaining spectral information, effectively recovering energy that would otherwise be lost in conventional single-layer designs.
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 improves light use efficiency and signal output, increasing the S/N ratio and color reproducibility of images compared to conventional sensors with color filters.
Implementation Method 1
an upper photoelectric conversion layer at which pixels that photoelectrically convert light of a specific color component of incident light and transmit light of any component other than the specific component of the incident light are two-dimensionally arrayed
Data Source
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Figure 3(a)~3(b)
AI summary
An imaging device includes: a plurality of first pixels that includes pixels of a plurality of color components and generates a first signal from incident light; a plurality of second pixels that generates a second signal from light that has transmitted at least a part of the first pixels; and a signal generation unit that generates a signal obtained by combining the first signal and the second signal.