Omnidirectional Image Sensor Spherical Wedge Structure
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Solution Overview
Problem
Existing image sensors with wide viewing angles face challenges in accuracy and curvature limitations, making it difficult to form thinner convex microlenses and bond them to devices effectively, resulting in restricted viewing angles.
Innovation Solution
An image sensor with a spherical structure featuring alternately connected spherical wedges and lateral photodiodes encapsulated in organic polymer, combined with Fresnel zone plates and a medium layer of polydimethylsiloxane (PDMS) for focal length adjustment, bonded using transfer printing to achieve a wider viewing angle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If polymer microlenses are combined with photodiodes using conventional methods, then the image sensor can be manufactured, but the viewing angle is limited and fabrication accuracy is reduced
Solution Approach 1:
The patent applies spherical geometry to the microlens structure, where each microlens is formed as a spherical cap with a specific radius of curvature. This spherical configuration enables the microlens to capture light from multiple directions simultaneously, achieving a wide viewing angle of 180 degrees or more while maintaining precise fabrication through standardized spherical wedge components that can be accurately manufactured and assembled
Solution Approach 2:
The image sensor is divided into multiple spherical wedge units, each containing a photodiode and a microlens. These modular spherical wedges can be independently manufactured and then precisely assembled around a central point, enabling both high fabrication accuracy through standardized components and a wide viewing angle through the geometric arrangement of multiple segments
2Volume of moving object
If convex microlenses are formed with thin structures, then the device becomes more compact, but bonding to the device becomes more difficult due to curvature
Solution Approach 1:
The microlens is nested within the spherical wedge structure, with the photodiode positioned at the center and the microlens forming the outer spherical cap. This nested configuration allows the thin microlens to be precisely positioned and bonded to the photodiode through the spherical wedge framework, making the bonding process easier despite the curvature by providing a structured mounting platform
Solution Approach 2:
The patent optimizes the radius of curvature and thickness parameters of the microlens to achieve a balance between compactness and bondability. By carefully selecting these geometric parameters, the microlens maintains a thin profile for device compactness while having sufficient structural characteristics to enable effective bonding to the photodiode through the spherical wedge interface
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 enhances the viewing angle of image sensors, allowing for a wider field of view similar to that of insect eyes, with improved fabrication accuracy and flexibility, enabling effective bonding and reduced interference.
Implementation Method 1
The plurality of microlenses may be configured as Fresnel zone plates (FZPs)
Implementation Method 2
a medium layer disposed between each of the plurality of microlenses and each of the plurality of photodiodes, respectively, and configured to adjust a focal length
Implementation Method 3
An image sensor with a structure of a compound eye of an insect has been developed by combining microlenses formed using a polymer and an elastic photodiode
Data Source
AI summary
An omnidirectional image sensor and a method of manufacturing the omnidirectional image sensor are provided. An image sensor may include a plurality of photodiodes, and a spherical structure comprising a plurality of protrusions, wherein the plurality of photodiodes are disposed between the plurality of protrusions, and wherein the spherical structure comprises a plurality of spherical wedges.