Shielding Plate Blocks Light Reflections in Image Sensors
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Solution Overview
Problem
Infrared image sensors experience image quality degradation due to light reflections from the read-out circuit and relay board, resulting in uneven light and dark distributions, which compromise the commercial value of the sensors.
Innovation Solution
An image sensor design incorporating a shielding plate made of aluminum nitride, positioned along the edges of the sensor chip and read-out circuit, to block light reflections and prevent them from entering the effective pixel region, combined with an underfill resin to secure the shielding plate and reduce thermal stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the read-out circuit area is extended off the sensor chip to accommodate more circuit components, then the device integration is improved, but light reflections from the extended area cause uneven light and dark distributions on the image sensor
Solution Approach 1:
The patent divides the package structure into functional zones by introducing a shielding plate that segments the light path. The shielding plate creates distinct regions: one for light reception by the sensor chip and another for the extended read-out circuit area, preventing light from spilling into areas where it should not be detected.
Solution Approach 2:
The shielding plate acts as an intermediary element between the window and the extended read-out circuit area. It mediates the light path by blocking reflections from the extended circuit area from reaching the sensor chip, thus preventing the harmful effect while allowing the beneficial extension of the read-out circuit.
2Manufacturing precision
If a shielding plate is introduced to block light reflections, then image quality uniformity is improved, but the device structure becomes more complex
Solution Approach 1:
The shielding plate is designed to serve multiple functions simultaneously: it blocks light reflections to improve image quality, provides structural support within the package, and can be integrated with the existing package components. This multi-functionality reduces the need for additional separate components.
Solution Approach 2:
The shielding plate is merged with the package structure rather than being a separate, standalone component. It is positioned and integrated within the existing package framework, combining the light-blocking function with the structural housing to minimize overall device complexity.
3Manufacturing precision
If the shielding plate blocks light from reaching the extended read-out circuit area, then reflected light from the window back surface is prevented from entering the sensor chip, but the shielding plate must be precisely positioned
Solution Approach 1:
The shielding plate is designed with pre-determined positioning features and dimensions that ensure correct placement during assembly. The structure is configured in advance to guide the shielding plate into its proper position, eliminating the need for complex alignment procedures during manufacturing.
Solution Approach 2:
The shielding plate is designed to fit into a standardized position within the package structure, creating an equipotential assembly process where the component naturally settles into the correct location without requiring complex alignment or adjustment procedures.
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 prevents light reflections, ensuring uniform image intensity distribution and maintaining high image quality by blocking light from reaching the sensor chip, thus enhancing the commercial value of the infrared image sensors.
Implementation Method 1
The shielding plate is configured to block transmission of light
Implementation Method 2
the infrared image sensor has been cooled by using, for example, a Peltier device
Data Source
AI summary
An image sensor includes a package having a window; a sensor chip facing the window, the sensor chip having a pixel region, the sensor chip having an electrode; a read-out circuit disposed farther from the window than the sensor chip, the read-out circuit having a read-out electrode connected to the electrode of the sensor chip; and a shielding plate disposed outside the pixel region of the sensor chip. The shielding plate is configured to block transmission of light.