Image Sensor Package with Large Air Cavity
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Solution Overview
Problem
Conventional image sensor packages suffer from poor imaging quality due to the short distance between the transparent lid and the image sensor chip, leading to multi-refraction and multi-reflection of light, resulting in ghost images.
Innovation Solution
An image sensor package structure with a large air cavity is introduced, where a plastic sheet is placed between the transparent lid and the chip, increasing the distance and improving imaging quality, and the transparent lid and plastic sheet are combined through injection molding to simplify manufacturing and enhance moisture protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the transparent lid is placed right on top of the image sensor chip to downsize the package, then the package size is reduced, but multi-refraction and multi-reflection of light occur leading to poor imaging quality and ghost images
Solution Approach 1:
The patent introduces a vertical air cavity dimension between the transparent lid and image sensor chip, transforming the problem from a 2D surface contact issue to a 3D spatial arrangement. By creating an air-filled cavity space, the design maintains compact overall footprint while providing sufficient optical path length to eliminate multi-refraction and ghost images, thus resolving the contradiction between miniaturization and imaging quality.
Solution Approach 2:
The patent introduces an intermediary air cavity between the transparent lid and the image sensor chip. This air medium serves as an optical buffer that prevents direct contact between the lid and chip, eliminating the harmful optical effects of multi-refraction and ghost images while maintaining the compact package structure. The air cavity acts as a mediator that preserves both the downsized form factor and high imaging quality.
2Ease of manufacture
If the transparent lid and plastic sheet are combined through injection molding, then the manufacturing process is simplified and manufacturing cost is reduced, but the structural complexity of the cover increases
Solution Approach 1:
The patent merges the transparent lid and plastic sheet into a single integrated cover component through injection molding. This combining of previously separate parts into one monolithic structure simplifies the manufacturing process by reducing assembly steps and lowering production costs, while the resulting integrated structure, though complex in design, becomes a single piece that eliminates interfaces and potential failure points.
Solution Approach 2:
The integrated cover structure performs multiple functions simultaneously: it provides optical transparency for light transmission, creates the air cavity for optical quality, offers mechanical protection for the chip, and serves as a moisture barrier. By combining these functions into a single multi-functional component, the patent achieves manufacturing simplicity despite structural complexity.
3Reliability
If package material is deposited to encapsulate the periphery of the transparent lid, then moisture protection is extended, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies package material to encapsulate the periphery of the transparent lid in advance, creating a pre-established moisture barrier. This preliminary protective action is performed during the manufacturing process before the product reaches the customer, ensuring long-term moisture protection. The encapsulation is applied as a preliminary step that seals the structure, preventing moisture ingress pathways and enhancing reliability without requiring complex post-manufacturing processes.
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 enlarged air cavity and increased distance between the transparent lid and the chip reduce ghost images, while the injection molding process lowers manufacturing costs and extends moisture protection, resulting in improved image-sensing performance and reliability.
Implementation Method 1
a transparent lid (e.g. glass), which allows light to pass through and be captured by the image sensor chip
Implementation Method 2
when light passes through the transparent lid and enters into the sensitization area of the image sensor chip, the multi-refraction or multi-reflection of light is likely to occur
Implementation Method 3
when light passes through the transparent lid and enters into the sensitization area of the image sensor chip, the multi-refraction or multi-reflection of light is likely to occur
Data Source
AI summary
The present invention discloses an image sensor package structure with a large air cavity. The image sensor package structure includes a substrate, a chip, a cover and a package material. The chip is combined with the substrate. A plastic sheet of the cover is adhered to the chip and a transparent lid of the cover is combined with the plastic sheet to provide a covering over a sensitization area of the chip so as to form an air cavity. The package material is arranged on the substrate and encapsulated around the chip and the cover. The plastic sheet having a predetermined thickness can increase the distance between the transparent lid and the chip to enlarge the air cavity. Thus, the image-sensing effect of the image sensor package structure can be improved and the ghost image problem resulting from multi-refraction and multi-reflection of light can be minimized.