Optical Proximity Sensor Package Top Plate Glue Dispensing
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Solution Overview
Problem
As the dimensions of optical proximity sensors are reduced, it becomes challenging to dispense glue within the optical transmit and receive cavities, slowing down the manufacturing throughput due to the decreased thickness of the optical elements.
Innovation Solution
A method is introduced where a package top plate is formed separately from the package body, allowing for the deposition of glue adjacent the optical openings before attaching the optical transmit and receive elements, which simplifies their attachment and increases manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the dimensions of optical proximity sensors are reduced, then the sensor size is decreased, but it becomes more difficult to dispense glue within the optical transmit and receive cavities
Solution Approach 1:
The package structure is segmented into a package body and a separate package top plate. The package top plate is formed with through-holes that receive the optical elements, and glue is deposited on the outer surfaces of the package top plate rather than inside deep cavities. This segmentation allows glue dispensing to occur on accessible external surfaces, resolving the difficulty of dispensing glue within reduced-dimension cavities.
2Volume of moving object
If the thickness of optical transmit and receive elements is reduced, then the sensor dimensions are decreased, but the throughput of making optical proximity sensors is slowed down
Solution Approach 1:
The package top plate is formed in advance with through-holes of appropriate size to receive the thin optical elements. The glue deposition is performed on the outer surfaces of the package top plate before final assembly, preparing the bonding surfaces in advance. This preliminary preparation eliminates time-consuming steps during final assembly, thereby maintaining high manufacturing throughput despite using thinner optical elements.
3Reliability
If glue is deposited within the optical transmit and receive cavities, then the optical elements are held in place, but the process becomes more difficult as sensor dimensions are reduced
Solution Approach 1:
Instead of depositing glue inside the cavities to hold optical elements, the approach is inverted: glue is deposited on the outer surfaces of the package top plate, and the optical elements are inserted through holes from the outside. The glue on the external surfaces bonds the optical elements as they are inserted, securing them in place. This inversion simplifies the process by making glue application accessible while maintaining reliable attachment.
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
This approach simplifies the attachment process of optical elements, enhances manufacturing throughput, and accommodates the reduced dimensions of optical proximity sensors by providing ample space for glue dispensing and forming a strong bond between the package body and top plate.
Implementation Method 1
The adhesive may be any suitable adhesive known to those of skill in the art. In one embodiment, the adhesive is an epoxy adhesive.
Data Source
AI summary
A method for making an optical proximity sensor includes forming a package top plate having an optical transmit opening and an optical receive opening extending therethrough, attaching an optical transmit element to the package top plate adjacent the optical transmit opening, and attaching an optical receive element to the package top plate adjacent the optical receive opening. A package body is formed onto the package top plate to define an optical transmit cavity receiving the optical transmit element and an optical receive cavity receiving the optical receive element.