Optical Sensor Packaging with Embedded Filters
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Solution Overview
Problem
Existing photoelectric sensors are limited in miniaturization due to the separate placement of the chip and light source on a PCB, with a gap between the light source and optical filter, which restricts further size reduction.
Innovation Solution
A packaging method that embeds optical filters in a plastic encapsulation layer, allowing the light-emitting unit and driver chip to be embedded in a second plastic encapsulation layer, with through holes for conductive material and passivation layers for electrical connectivity, enabling a compact optical sensor device with reduced size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the chip and light source are placed separately on a PCB with a gap between the light source and optical filter, then the electrical connectivity and optical filtering functions are achieved, but the device size is increased and miniaturization is limited
Solution Approach 1:
The patent merges the optical filter and the light-emitting unit by embedding the optical filter within the second plastic encapsulation layer that also contains the light-emitting unit and driver chip. This eliminates the gap between the light source and optical filter, reducing the overall device volume while maintaining the necessary optical filtering function.
Solution Approach 2:
The patent implements nesting by placing the optical filter inside the encapsulation layer that already contains the light-emitting unit and driver chip. This nested arrangement allows multiple functional components to occupy the same spatial envelope, significantly reducing the device footprint and enabling miniaturization.
2Reliability
If the optical filter is placed on a separate cover with a gap from the light source, then the optical filtering function is achieved, but the device complexity and size are increased
Solution Approach 1:
The patent combines the optical filter with the light-emitting unit by embedding both within the same second plastic encapsulation layer. This merged structure maintains the optical filtering function while eliminating the need for a separate cover and gap, thereby reducing device size.
3Volume of moving object
If the components are embedded in plastic encapsulation layers with through holes for conductive material, then the device size is reduced and electrical connectivity is maintained, but the manufacturing complexity is increased
Solution Approach 1:
The patent applies preliminary action by pre-forming the plastic encapsulation layers with through holes at specific positions before embedding the components. This allows the conductive material to be subsequently filled through these pre-prepared pathways, simplifying the overall manufacturing process compared to creating through holes after component placement.
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 embedding of optical filters and components in plastic encapsulation layers results in a significantly reduced size of the optical sensor device, achieving space savings while maintaining electrical connectivity and functionality.
Implementation Method 1
filling a plastic encapsulation material between the first optical filter and the second optical filter and curing the plastic encapsulation material to form a first plastic encapsulation layer
Data Source
AI summary
A driver chip, a packaging method for optical filter structure, an optical sensor device and a packaging method for optical sensor device are disclosed. The packaging method for optical filter structure includes providing first carrier substrate, one side of first carrier substrate provided with first adhesive layer; placing at least one first optical filter and at least one second optical filter on first adhesive layer in such a manner that first and second optical filters are spaced apart from each other; filling plastic encapsulation material between first and second optical filters and curing plastic encapsulation material to form a first plastic encapsulation layer. Opposing sides of the first optical filter and opposing sides of the second optical filter are exposed from the first plastic encapsulation layer; and removing the first carrier substrate. In this way, optical sensor device is allowed to have a reduced size, which results in space savings.