Optical Sensor Shielding Layout for EMI-Resistant Photodetection
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Solution Overview
Problem
Existing photodetection apparatuses face challenges in effectively shielding signal processing circuits from external noise, which can affect the accuracy of light detection, particularly in environments with electromagnetic interference.
Innovation Solution
The proposed photodetection apparatus incorporates a lead frame and conductive pattern on a mounting board to shield the signal processing circuit, with the lead frame exposing the light receiving surface of the optical sensor and being thicker than the conductive pattern, and the conductive pattern facing the signal processing circuit to provide dual-sided shielding without the need for additional shielding components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If additional shielding components are added to protect the signal processing circuit from electromagnetic noise, then noise shielding effectiveness is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple shielding functions into the lead frame structure itself. The lead frame serves both as an electrical connection component and as an electromagnetic shield for the signal processing circuit. By integrating the shielding function into an existing component rather than adding separate shielding elements, the patent reduces overall device complexity while maintaining effective noise protection.
Solution Approach 2:
The lead frame is designed to perform multiple functions simultaneously: providing electrical connections, mechanical support, and electromagnetic shielding. This multi-functional design eliminates the need for dedicated shielding components, thereby simplifying the device structure while achieving comprehensive noise protection for the signal processing circuit.
2Object-affected harmful factors
If the lead frame is made thicker to improve shielding effectiveness, then noise blocking capability is improved, but manufacturing complexity increases
Solution Approach 1:
The lead frame is designed with non-uniform thickness, being thicker in regions where superior shielding is required and thinner in other areas. This localized variation in thickness optimizes noise blocking capability where needed while maintaining ease of manufacturing by avoiding uniformly thick designs that would be more difficult and costly to produce.
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 configuration effectively reduces electromagnetic noise interference, enhancing the accuracy of light detection and simplifying the structure by integrating the optical sensor, signal processing circuit, and lead frame with resin sealing, while maintaining effective noise blocking across various frequency bands.
Implementation Method 1
The photodetection apparatus includes a lead frame that shields a surface of the signal processing circuit on the second surface side, and a conductive pattern that faces the signal processing circuit and shields a surface of the signal processing circuit on the first surface side
Implementation Method 2
The optical sensor device includes an optical sensor that includes a light receiving surface on the second surface side
Data Source
AI summary
Provided is a photodetection apparatus which includes a mounting board, and an optical sensor device that includes a first surface on the mounting board side and a second surface on a side opposite to the mounting board, and is mounted on the mounting board. The optical sensor device includes an optical sensor that includes a light receiving surface on the second surface side, a signal processing circuit that is electrically connected to the optical sensor, and a lead frame that is provided on the second surface side with respect to the signal processing circuit, and shields a surface of the signal processing circuit on the second surface side. The mounting board has a conductive pattern that faces the signal processing circuit and shields a surface of the signal processing circuit on the first surface side.