Angular Filtered Image Sensor for Lensless Sharp Imaging
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Solution Overview
Problem
Conventional image acquisition systems without an optical system face challenges in achieving sharp image formation on the image sensor, particularly due to limitations in surface area and distance between the object and the sensor, leading to suboptimal image sharpness and increased manufacturing complexity.
Innovation Solution
An image sensor design incorporating organic photodetectors with an angular filter positioned less than 20 μm away, featuring a layer with openings that filter radiation based on incidence angle, enhancing image sharpness and allowing for a larger surface area and reduced distance between the object and sensor, while maintaining high transmittance and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If no optical system is used to form a sharp image on the image sensor, then the device complexity and manufacturing cost are reduced, but the image sharpness deteriorates
Solution Approach 1:
The angular filter is segmented into multiple openings arranged in a specific pattern, where each opening corresponds to a photodetector. This segmentation allows the filter to selectively transmit light at specific angles to each photodetector, achieving sharp image formation without requiring a complex optical system. The segmented structure enables precise angular control of incident light while maintaining a simple overall device architecture.
2Area of stationary object
If the surface area of the image sensor is increased, then the field of view and light collection are improved, but the manufacturing precision and alignment difficulty increase
Solution Approach 1:
The angular filter and photodetectors are designed to work together in a self-aligning manner. The geometric relationship between the openings in the angular filter and the photodetectors is configured such that the structure itself guides the light at the correct angles, eliminating the need for high-precision external alignment during manufacturing. This self-service mechanism allows for larger sensor areas without proportionally increasing alignment difficulty.
3Length of moving object
If the distance between the object and the image sensor is reduced, then the device compactness is improved, but the image sharpness without optical system deteriorates
Solution Approach 1:
The angular filter changes the angular parameter of incident light by blocking certain angles and transmitting others. This parameter change in light direction compensates for the reduced distance between object and sensor, enabling sharp image formation even in compact configurations. The filter effectively controls the angular distribution of light reaching each photodetector, maintaining image quality despite the shortened optical path.
4Measurement precision
If an angular filter with small opening-to-photodetector distance is used, then the image sharpness is improved, but the manufacturing complexity increases
Solution Approach 1:
The angular filter structure is merged with the photodetector array in a integrated design where the openings are positioned and sized relative to the photodetectors to achieve the desired angular filtering effect. This merging of functions reduces the need for separate complex alignment mechanisms and simplifies the overall manufacturing process while maintaining the sharpness benefits of close spacing.
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 effectively improves image sharpness and increases the surface area of the image sensor, reducing manufacturing complexity and costs by utilizing an angular filter with strategically placed openings to optimize radiation incidence, thereby enhancing image acquisition efficiency.
Implementation Method 1
the angular filter covering the image sensor and being configured to block the rays of said radiation having an incidence relative to a direction orthogonal to the surface greater than a threshold and to give way to rays of said radiation having an incidence relative to a direction orthogonal to the surface smaller than the threshold
Implementation Method 2
organic photodetectors and an angular filter less than 20 μm away from the photodetectors
Data Source
AI summary
An image sensor includes organic photodetectors and an angular filter less than 20 μm away from the photodetectors. Further, a method of manufacturing an image sensor includes the forming of organic photodetectors and of an angular filter less than 20 μm away from the photodetectors.