Spectral Filter Image Sensor for Multi-Band Color Separation
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Solution Overview
Problem
Existing image sensors struggle with improving color reproduction accuracy and object recognition performance due to constraints from relatively large volumes and high complexity levels of optical device components.
Innovation Solution
The development of an image sensor that includes a spectral filter with a routing filter array and a spectral filter array, capable of separating incident light into at least four different wavelength bands and providing these separated bands to the sensor pixels, thereby enhancing color reproduction and object recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a spectral filter with multiple wavelength bands is used to improve color reproduction accuracy and object recognition performance, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The spectral filter is divided into multiple independent unit filters, each responsible for a specific wavelength band. Each unit filter contains a cavity with specific refractive index and thickness designed for a particular spectral range, allowing the complex spectral filtering function to be segmented into manageable, independent components that can be manufactured and optimized separately
Solution Approach 2:
Different regions of the spectral filter are designed with locally optimized properties. Each unit filter has a cavity with specific refractive index and thickness tailored to its local spectral requirements. The routing filter array also uses nano-structures with locally varied geometries to direct different wavelength bands to appropriate pixels, ensuring each region performs its specific spectral function optimally
2Measurement precision
If a spectral filter with multiple wavelength bands is used to improve object recognition performance, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The spectral filter is divided into multiple independent unit filters, each responsible for a specific wavelength band. Each unit filter contains a cavity with specific refractive index and thickness designed for a particular spectral range, allowing the complex spectral filtering function to be segmented into manageable, independent components that can be manufactured and optimized separately
Solution Approach 2:
The spectral filter array serves multiple functions simultaneously: it performs spectral separation, wavelength band filtering, and light routing to different pixel types. The routing filter array with its nano-structures provides both color separation and focal plane routing capabilities, reducing the need for additional separate optical components
3Volume of stationary object
If conventional optical components are used, then device volume is reduced, but color reproduction accuracy deteriorates
Solution Approach 1:
The patent transitions from conventional planar optical filters to a three-dimensional cavity-based spectral filter structure. The cavities with controlled depth and refractive index provide spectral filtering in the vertical dimension, enabling more sophisticated spectral separation within a compact footprint. The routing filter array also uses vertical nano-structure arrangements to achieve color separation and light routing in the depth direction
4Device complexity
If conventional optical components are used, then device complexity is reduced, but object recognition performance deteriorates
Solution Approach 1:
The patent systematically varies critical parameters of the spectral filter components to optimize performance. The cavity thickness, refractive index, and geometric dimensions are precisely controlled to achieve specific transmission spectra. The routing filter nano-structures use varied parameters such as pillar diameter, spacing, and height to control light routing efficiency and spectral separation characteristics
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 solution achieves improved color reproduction accuracy and object recognition performance by effectively separating and condensing light into multiple wavelength bands, reducing light absorption, and increasing light utilization efficiency.
Implementation Method 1
a routing filter array including a plurality of nano-structures configured to color-separate the incident light into at least three different wavelength bands
Implementation Method 2
configured to condense the separated incident light onto the plurality of pixels
Implementation Method 3
a spectral filter array between the sensor substrate and the routing filter array, and including a plurality of unit filters having different transmission spectrums
Implementation Method 4
The plurality of nano-structures may be further configured to change a phase of the incident light
Data Source
AI summary
Provided are an image sensor including a spectral filter and an electronic apparatus. An image sensor includes a sensor substrate including a plurality of pixels configured to sense light, and a spectral filter configured to separate incident light into at least four different wavelength bands and to provide the separated incident light to the plurality of pixels. The spectral filter includes a routing filter array including a plurality of nano-structures configured to color-separate the incident light into at least three different wavelength bands and to condense the light onto the plurality of pixels, and a spectral filter array between the sensor substrate and the routing filter array, and including a plurality of unit filters having different transmission spectrums, the plurality of unit filters respectively corresponding to the plurality of pixels.