Image Sensor Filter Unit for Near-Infrared Sensitivity
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Solution Overview
Problem
Image sensors face a trade-off between reducing color distortion and achieving high sensitivity, as infrared cutoff filters minimize distortion but limit light sensitivity, while removing them increases color distortion risk.
Innovation Solution
An image sensor design incorporating a filter unit that selectively passes visible light and non-visible wavelengths up to 800 nm, while minimizing wavelengths beyond 800 nm, using a combination of filter units to allow near-infrared light to contribute to image data without significant color distortion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an infrared cutoff filter is used, then color distortion is reduced, but light sensitivity is decreased
Solution Approach 1:
The filter unit is divided into multiple wavelength bands: a first passband for visible light (380-780nm), a first stopband for near-infrared light (780-850nm), and a second stopband for far-infrared light (850nm+). This segmentation allows selective transmission of different wavelength ranges, achieving both color accuracy and sensitivity by passing visible light while blocking problematic infrared wavelengths.
Solution Approach 2:
The filter unit applies different filtering characteristics to different wavelength regions. It maintains high transmission for visible wavelengths (preserving sensitivity) while applying strong attenuation specifically in the near-infrared region (780-850nm) to prevent color distortion. This localized quality control resolves the contradiction by being selective rather than uniform in its filtering approach.
2Use of energy by moving object
If the infrared cutoff filter is removed, then light sensitivity is increased, but color distortion increases
Solution Approach 1:
The filter unit extracts and removes only the specific problematic wavelength components (near-infrared light at 780-850nm and far-infrared light above 850nm) from the incident light spectrum. By selectively extracting and eliminating only these harmful wavelength components while preserving the visible light spectrum, the invention achieves high sensitivity without color distortion.
3Use of energy by moving object
If the filter bandwidth is extended to 800 nm, then sensitivity is enhanced, but near-infrared interference increases
Solution Approach 1:
The filter unit dynamically adjusts its transmission characteristics across different wavelengths, creating a multi-band response with passbands and stopbands. This dynamic filtering approach allows the system to enhance sensitivity in the visible range while simultaneously suppressing near-infrared interference through strategically positioned stopbands, resolving the contradiction between extended bandwidth and interference reduction.
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 design enhances light sensitivity by extending the bandwidth to 800 nm while minimizing color distortion, enabling high sensitivity images without undesirable effects from near-infrared light.
Implementation Method 1
a filter unit to filter incident light, the filter unit configured to pass wavelengths of the incident light corresponding to a visible light region including visible wavelengths, pass wavelengths of the incident light corresponding to a defined first region including non-visible wavelengths longer than the visible wavelengths, and minimize passage of wavelengths of the incident light corresponding to a second region including wavelengths longer than the passed light corresponding to the first region
Implementation Method 2
a sensor unit configured in the image sensor to detect light having passed through the filter unit
Data Source
AI summary
An image sensor capable of ensuring high sensitivity image and minimizing color distortion is provided. The image sensor includes a first filter unit, a second filter unit formed at a lower part of the first filter unit and a sensor unit formed at a lower part of the second filter unit. The first filter unit is configured to pass light corresponding to a visible light region, pass light corresponding to a first region of a longer wavelength than the light corresponding to the visible region and cut off light corresponding to a second region of a longer wavelength than the light corresponding to the first region. The second filter unit is configure to pass light having a predetermined wavelength in a wavelength range corresponding to the visible light region among the light passing through the first filter unit and pass light corresponding to the first region. The sensor unit is configured to detect the light passing through the second filter unit.