Angle-Sensitive Pixel Sensor Using Talbot Effect for 3D Light Field Imaging
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Solution Overview
Problem
Conventional imaging technologies fail to capture the incident angle and polarization properties of light rays, limiting their ability to provide a complete description of the light field, which is essential for three-dimensional reconstruction and other advanced imaging applications. Existing solutions require multiple lenses or moving parts, are costly, and have suboptimal quantum efficiency and angular acuity.
Innovation Solution
A lens-less, angle-sensitive pixel (ASP) device manufactured in a standard CMOS process using periodic light diffracting structures to capture the intensity and direction of light through the Talbot effect, enabling the measurement of light field properties without additional optical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional imaging uses a large array of light sensors to create an intensity map, then the intensity measurement is improved, but the incident angle and polarization information is lost
Solution Approach 1:
The sensor array is segmented into multiple sensor elements, where each element is assigned to detect light from a specific angular range. This segmentation allows the system to capture both intensity and angular information simultaneously by distributing different angular measurements across different sensor elements, thereby resolving the contradiction between intensity measurement precision and information loss.
2Loss of information
If light field imaging uses an array of pinhole cameras to capture incident angle-dependent intensity, then the light field information is improved, but the device complexity and cost increase significantly
Solution Approach 1:
The patent replaces the mechanical/optical system of multiple pinhole cameras with a single planar sensor array that directly detects angular information through the angular response characteristics of individual sensor elements. This substitution eliminates the need for complex optical components while preserving light field measurement capabilities, thereby resolving the contradiction between light field information quality and device complexity.
3Volume of moving object
If light field imaging uses micro-lenses to emulate camera arrays, then the device size is reduced, but the quantum efficiency and angular acuity become suboptimal
Solution Approach 1:
Each sensor element in the array is designed with specific local optical characteristics and angular response properties tailored to its position and function. This local quality optimization allows each element to maintain high quantum efficiency and angular acuity while the overall array achieves compact size, thereby resolving the contradiction between device size and measurement reliability.
4Measurement precision
If a lens is used to ensure the intensity map represents an object of interest, then the spatial information is improved, but the incident angle information is completely lost
Solution Approach 1:
The patent transitions from conventional two-dimensional intensity mapping to a three-dimensional light field measurement by adding angular information as a third dimension. The sensor array measures not only intensity at each position but also the angular distribution of light, thereby capturing both spatial and angular information simultaneously without requiring a lens, resolving the contradiction between spatial information quality and incident angle information loss.
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 ASP device achieves high sensitivity and spatial resolution, allowing for the reconstruction of three-dimensional structures and improved light field imaging capabilities, reducing the size and cost of imaging instruments while maintaining high quantum efficiency.
Implementation Method 1
A lens-less, angle-sensitive pixel (ASP) device manufactured in a standard CMOS process using periodic light diffracting structures to capture the intensity and direction of light through the Talbot effect
Implementation Method 2
utilize the Talbot effect of periodic light diffracting structures to characterize incident light by its magnitude and direction
Data Source
AI summary
An angle-sensitive pixel (ASP) device that uses the Talbot effect to detect the local intensity and incident angle of light includes a phase grating disposed above a photodiode assembly or a phase grating disposed above an analyzer grating that is disposed above a photodiode assembly. When illuminated by a plane wave, the upper grating generates a self-image at a selected Talbot depth. Several such structures, tuned to different incident angles, are sufficient to extract local incident angle and intensity. Arrays of such structures are sufficient to localize light sources in three dimensions without any additional optics.