Curved Image Sensor via Substrate Swelling
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Solution Overview
Problem
Conventional optical systems with flat image sensor chips face design constraints related to chromatic and spatial aberrations, limiting their performance and light intensity uniformity across the sensor surface.
Innovation Solution
A curved image sensor chip is fabricated by bonding a volume-changing substrate to the image sensor chip, using chemical or physical reactions to generate bending forces, allowing the chip to be shaped into spherical, aspheric, or other forms, thereby reducing design constraints and improving optical system performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a flat image sensor chip is used, then the manufacturing process is simple, but the optical system performance is limited due to chromatic and spatial aberrations
Solution Approach 1:
The patent applies curvature to the image sensor chip surface by bonding it to a substrate that undergoes volumetric swelling. The swelling substrate generates bending forces that curve the sensor chip surface into spherical, aspheric, or other desired shapes, thereby improving optical system performance by reducing chromatic and spatial aberrations while maintaining manufacturing feasibility
2Manufacturing precision
If the image sensor chip is curved, then the optical system performance is improved, but the risk of cracking increases due to mechanical stress
Solution Approach 1:
The patent changes the physical state and volume of the substrate through chemical or physical reactions (volumetric swelling). This parameter change generates controlled bending forces that curve the sensor chip while the gradual nature of the swelling process allows stress management, reducing the risk of cracking compared to mechanical bending methods
3Shape
If a substrate is bonded to the image sensor chip to create curvature, then the shaping capability is improved, but the device complexity increases
Solution Approach 1:
The substrate serves a dual function: it acts as both the bonding layer and the actuator that generates curvature through volumetric swelling. This self-service approach eliminates the need for separate actuation mechanisms, reducing device complexity while maintaining advanced shaping capabilities for spherical, aspheric, and other complex surfaces
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 curved image sensor chip enhances optical system performance by providing uniform light intensity and spatial frequency response, with reduced thermal stresses and potential for higher resolution, while maintaining mechanical strength and minimizing the risk of cracking.
Implementation Method 1
a substrate may be coupled (e.g., bonded, adhered, deposited, or attached) to the backside of the image sensor. The substrate may then be subjected to any number of chemical or physical reactions that increase the volume of the substrate. The increasing volume produces bending forces on the image sensor due to strain gradients between the substrate and the image sensor.
Data Source
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AI summary
In some examples, techniques and architectures for fabricating an image sensor chip having a curved surface include placing a substrate on a first surface of an image sensor chip, wherein the first surface of the image sensor chip is opposite a second surface of the image sensor chip, and wherein the second surface of the image sensor chip includes light sensors to generate electrical signals in response to receiving light. Fabricating also includes modifying a volume of the substrate so as to impart forces on the image sensor chip to produce a curved image sensor chip.