Image Sensor Infrared Luminance Pixel Low-Light Sensitivity
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Solution Overview
Problem
Miniaturization and increased resolution of image sensors lead to difficulties in improving luminance sensitivity under low-illumination environments, such as nighttime or indoor conditions.
Innovation Solution
An image sensor configuration with a pixel array that includes both visible light-sensing pixels and an infrared light-sensing pixel, where the infrared light-sensing pixel is integrated to enhance luminance sensitivity by selectively absorbing infrared light and preventing its interference with visible light-sensing pixels, thereby improving photoelectric conversion efficiency and reducing signal delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the image sensor is miniaturized and resolution is increased, then the sensor size and pixel density improve, but luminance sensitivity under low-illumination environments deteriorates
Solution Approach 1:
The pixel array is segmented into multiple pixel types including red, green, blue, and luminance pixels. The luminance pixels are specifically designed to detect luminance information with high sensitivity, while color pixels handle color information. This segmentation allows the sensor to maintain high luminance sensitivity even when miniaturized, as the luminance pixels can be optimized independently for low-light performance.
Solution Approach 2:
The patent utilizes the vertical dimension by stacking multiple photoelectric conversion layers (red, green, blue, and luminance layers) in the depth direction. This three-dimensional arrangement allows each layer to capture specific wavelength ranges or luminance information, enabling high luminance sensitivity without increasing the horizontal sensor area, thus resolving the contradiction between miniaturization and luminance sensitivity.
2Adaptability or versatility
If more pixel types are added to capture different light wavelengths, then spectral sensitivity improves, but device complexity increases
Solution Approach 1:
The patent merges multiple functions into a unified pixel array structure. The luminance pixels serve dual purposes: they detect luminance information for brightness perception and also contribute to color information through the CFA pattern. The color pixels (red, green, blue) simultaneously capture color information and contribute to luminance. This merging reduces the need for separate dedicated luminance sensors, thereby simplifying the overall device complexity while maintaining spectral sensitivity.
Solution Approach 2:
Each pixel type in the array is designed to perform multiple functions. For example, green pixels not only capture green light for color information but also contribute significantly to luminance detection due to the human eye's sensitivity to green wavelengths. This multi-functionality allows the sensor to achieve broad spectral sensitivity without requiring separate specialized sensors for each function, thus reducing device complexity.
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
The solution enables high-sensitivity and high-resolution image capture in low-illumination environments by enhancing luminance sensitivity and maintaining efficient visible light transmittance, allowing for high-contrast images across a wide range of illumination conditions.
Implementation Method 1
the infrared light-sensing pixel is integrated to enhance luminance sensitivity by selectively absorbing infrared light and preventing its interference with visible light-sensing pixels
Implementation Method 2
An imaging device generates an image and may store the same as an electrical signal. The imaging device includes an image sensor that dissembles the incident light into separate components according to incident light wavelength and converts each component to an electrical signal.
Data Source
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AI summary
An image sensor includes at least one first pixel configured to sense light in a visible light wavelength spectrum and a second pixel configured to sense light in an infrared light wavelength spectrum. The second pixel includes a first photoelectric device defined in the second pixel. The first photoelectric device includes an infrared light absorption layer between a first electrode and a second electrode and configured to selectively absorb light in an infrared spectrum. The second pixel may be configured to compensate the luminance sensitivity of the image sensor. The first and second pixels may be included in a unit pixel group. The image sensor may include an array of multiple unit pixel groups arranged in one or more rows and one or more columns.