Image Sensor Phase Imaging via Diffraction Gratings
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Solution Overview
Problem
Traditional phase imaging methods for translucent or transparent samples are complex, costly, and provide a limited field of observation, requiring precise assemblies and often necessitate the use of phase reconstruction algorithms that are inefficient without high signal-to-noise ratio images.
Innovation Solution
An image sensor with a matrix of pixels, featuring a mask with opaque elementary masks and diffraction gratings that couple and extract light waves to directly measure intensity and phase differences without the need for phase reconstruction algorithms, using a waveguide and diffraction gratings to propagate light waves between open and masked pixels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional phase imaging methods are used, then phase information can be obtained, but the device complexity and cost increase significantly
Solution Approach 1:
The image sensor is divided into three distinct pixel types with different functions: open pixels for direct light detection, masked pixels for phase information detection, and guided pixels for reference signal detection. This segmentation allows each pixel type to perform its specific function efficiently, obtaining phase information without requiring complex external phase contrast optics.
Solution Approach 2:
The image sensor integrates multiple functions into a single device: it performs both intensity imaging and phase contrast imaging simultaneously, eliminating the need for separate phase contrast microscopes and auxiliary optics. The sensor acts as a universal imaging device that captures both amplitude and phase information in one measurement.
2Measurement precision
If phase reconstruction algorithms are used, then phase information can be extracted, but the processing time and computational complexity increase
Solution Approach 1:
The sensor performs preliminary action by directly measuring phase information at the detection stage through its specialized pixel structure. The masked pixels and guided pixels are pre-configured to capture phase-related signals directly, eliminating the need for post-processing reconstruction algorithms and significantly reducing processing time.
3Area of stationary object
If lensless imaging is used, then the field of observation is widened, but phase information is lost
Solution Approach 1:
The image sensor is divided into three distinct pixel types with different functions: open pixels for direct light detection, masked pixels for phase information detection, and guided pixels for reference signal detection. This segmentation allows each pixel type to perform its specific function efficiently, obtaining phase information without requiring complex external phase contrast optics.
Solution Approach 2:
The waveguide structure acts as an intermediary element that guides reference light waves to the guided pixels, enabling phase information extraction in a lensless configuration. The mask with its opaque elementary masks and openings serves as another intermediary that separates and directs different light components to appropriate pixel types.
4Measurement precision
If diffraction gratings and waveguides are added, then phase information can be directly detected, but the manufacturing complexity increases
Solution Approach 1:
The diffraction gratings and waveguides are merged with the image sensor structure itself, forming an integrated device. The gratings are fabricated as surface structures on the sensor, and the waveguides are formed within the sensor substrate, combining multiple optical functions into a single manufacturable component that can be produced using standard semiconductor fabrication techniques.
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 approach simplifies the imaging process, reduces costs, and enhances the field of observation by directly obtaining phase information from intensity measurements, improving the efficiency of phase imaging without the need for complex reconstruction algorithms.
Implementation Method 1
a first diffraction grating, extending opposite at least one open pixel, and configured to couple a portion of the incident light wave into the waveguide, so as to form a guided wave
Implementation Method 2
a waveguide, forming a band extending opposite masked pixels and open pixels
Implementation Method 3
a second diffraction grating, extending opposite a masked pixel, and configured to extract a part of the guided wave, propagating in the waveguide, such that the wave thus extracted propagates towards the masked pixel
Data Source
Figure 1A~1B
Figure 1C~1D
Figure 2A~2B
AI summary
An object of the invention is an image sensor (20) comprising a pixel matrix (30), extending along a detection plane (P), and configured to form an image of an incident light wave (12), propagating along a spectral band (Δλ), along a propagation axis (Z), the image sensor being characterized in that it comprises a mask (25), formed of different opaque elementary masks (25i), extending parallel to the detection plane, between which are extended apertures (26i), through which the incident light wave is able to propagate in the direction of the detection plane (P), the pixel matrix being divided into: - open pixels (31i) extending opposite the apertures (26i); - masked pixels (32i), each masked pixel being defined by a projection of an elementary mask (25i) along the propagation axis (Z) onto the pixel matrix, each masked pixel being associated with the elementary mask facing it;the image sensor comprising, between the open pixels (31i) and the apertures (26i): - a waveguide (23), extending in front of masked pixels and open pixels; - a first diffraction grating (21i), extending in front of at least one open pixel (31i), and configured to couple a part of the incident light wave (12) in the waveguide (23); - a second diffraction grating (22i), extending in front of a masked pixel (32i), and configured to extract a part of a guided wave (13i), propagating in the waveguide (23).