Wafer Scale Image Sensor Package with Black Cavity Light Blocking
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Solution Overview
Problem
Wafer scale packaging of image sensor chips using transparent materials like glass or epoxy allows ambient light to interfere with the operation of the image sensor, degrading its performance, as there is no black cavity to block external light.
Innovation Solution
An optical mechanism and positioning structure that includes a wafer scale image sensor package with a die, an intermediate layer, and a transparent layer, featuring a filter and reflecting layers, along with a blocking member and securing member to securely attach the package to a substrate, blocking unnecessary light and allowing specific wavelengths to pass through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If transparent materials are used to enclose the image sensor chip in wafer scale packaging, then the manufacturing process is simplified and the chip can be directly applied to applications, but ambient light can pass through the transparent materials and interfere with the image sensor operation
Solution Approach 1:
The transparent encapsulating layer is segmented by introducing a black cavity structure that divides the internal space into light-receiving and light-blocking regions. This segmentation allows the transparent material to maintain its ease of manufacture while the black cavity segments the light path to prevent ambient light interference with the image sensor.
Solution Approach 2:
A black cavity structure is introduced as an intermediary element between the transparent encapsulating layer and the image sensor chip. This intermediary component blocks ambient light from reaching the sensor while allowing the transparent materials to remain in place, thus maintaining manufacturing simplicity while solving the light interference problem.
2Reliability
If a black cavity is used to block ambient light, then the image sensor performance is protected, but the wafer scale packaging advantage of using transparent materials is lost
Solution Approach 1:
The black cavity structure is merged with the transparent encapsulating layer to form an integrated package structure. The cavity is formed within the transparent material itself rather than being a separate component, combining the light-blocking function with the encapsulating function to reduce overall structural complexity while maintaining both protection and manufacturing advantages.
Solution Approach 2:
The transparent encapsulating layer is modified locally by forming a black cavity in specific regions while maintaining transparency in other regions. This local quality change allows the package to have both transparent areas for light transmission and black areas for light blocking, achieving the desired functionality without completely sacrificing the wafer scale packaging advantages.
3Measurement precision
If the image sensor chip is positioned at a fixed height for optical navigation, then the optical detection function is achieved, but the package structure becomes less adaptable to different applications
Solution Approach 1:
The positioning structure is designed with adjustable elements that allow the image sensor chip to be positioned at different heights relative to the substrate. This dynamic positioning capability enables the same package structure to be adapted for different optical detection requirements while maintaining precise positioning for each specific application.
Solution Approach 2:
The package structure incorporates a universal positioning mechanism that can accommodate different mounting requirements and substrate types. The adjustable height positioning system provides multi-functionality, allowing the same package to be used in various applications such as optical navigation, proximity sensing, and other optical detection tasks with different height requirements.
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
Effectively prevents ambient light from interfering with the image sensor chip, ensuring stable operation by securely positioning the package and filtering out unwanted light, thereby enhancing the performance of the image sensor.
Implementation Method 1
block or absorb unnecessary light
Implementation Method 2
allow specific wavelengths to pass through
Data Source
AI summary
There is provided an optical mechanism including a substrate, an image sensor chip, a light source, a blocking member and a securing member. The image sensor chip is attached to the substrate and has an active area. The light source is attached to the substrate. The blocking member covers the image sensor chip and has an opening to expose at least the active area of the image sensor chip. The securing member fits on the blocking member to secure the blocking member to the substrate.