Stacked Imaging Device Infrared Separation
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Solution Overview
Problem
Existing solid-state imaging devices struggle to effectively separate visible light and infrared light signals, leading to contamination of visible light images with infrared light components, which affects image quality.
Innovation Solution
The implementation of a stacked substrate configuration with a first substrate containing photoelectric conversion units for visible light and an infrared absorption layer, and a second substrate with additional photoelectric conversion units for infrared light, along with a signal processing circuit to correct and generate separate visible and infrared light image signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a single substrate with photoelectric conversion units is used, then the device structure is simple, but it cannot effectively separate visible light and infrared light signals leading to image quality degradation
Solution Approach 1:
The imaging device is divided into multiple substrates: a first substrate with first photoelectric conversion units for visible light, a second substrate with second photoelectric conversion units for infrared light, and an intermediate substrate with infrared absorption layers. This segmentation allows each substrate to specialize in detecting specific wavelength ranges, effectively separating visible and infrared light signals to improve image quality.
Solution Approach 2:
The patent transitions from a two-dimensional planar arrangement to a three-dimensional stacked configuration. Multiple substrates are arranged in the thickness direction with specific functional layers positioned between them, utilizing the third dimension to achieve effective light separation and signal isolation that cannot be accomplished in a single plane.
2Measurement precision
If visible light cut filter is used between substrates, then infrared light can be blocked, but visible light transmission is reduced affecting image brightness
Solution Approach 1:
Instead of using a visible light cut filter that would block both infrared and visible light, the patent extracts the infrared absorption function into a separate intermediate substrate positioned between the first and second substrates. This allows the visible light path to remain unobstructed while specifically targeting and absorbing infrared light, thus maintaining visible light transmission for bright images while achieving effective infrared separation.
Solution Approach 2:
An intermediate substrate serving as a mediator is introduced between the first substrate (visible light detection) and the second substrate (infrared detection). This intermediate substrate contains infrared absorption layers that selectively absorb infrared light passing through the first substrate, preventing infrared contamination in visible light images while allowing visible light to pass through to the second substrate for infrared image generation.
3Device complexity
If multiple photoelectric conversion units detect both visible and infrared light, then the device structure is simple, but infrared light components contaminate visible light images
Solution Approach 1:
Different substrates are assigned different functional qualities: the first substrate is optimized for visible light detection, the intermediate substrate provides infrared absorption, and the second substrate detects infrared light. This local quality differentiation ensures that each component performs its specific function optimally, preventing infrared contamination in visible light images while maintaining structural organization.
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 the quality of visible light images by removing infrared light components and enhances the dynamic range of infrared light images, resulting in better image fidelity and reduced noise.
Implementation Method 1
an infrared absorption layer which absorbs infrared light and transmits light having a wavelength of only green light or blue light
Implementation Method 2
a first photoelectric conversion unit which generates a first signal based on green light and infrared light
Data Source
AI summary
In an imaging device, a plurality of first photoelectric conversion units generate a first signal based on first visible light and infrared light. A plurality of second photoelectric conversion units generate a second signal based on only second visible light. An infrared absorption layer absorbs the infrared light and transmits only the second visible light. A plurality of third photoelectric conversion units generate a third signal based on the infrared light. A signal processing circuit generates a fourth signal by correcting the first signal using the third signal. The signal processing circuit generates a visible light image signal on the basis of the second signal and the fourth signal. The signal processing circuit generates an infrared light image signal on the basis of the third signal.