Optical Sensor Module Shadowing Cross-Talk
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Solution Overview
Problem
Optical sensor modules face challenges with light pollution and cross-talk due to the close proximity of optical emitters, sensors, and ASICs, which decreases performance and requires a solution to minimize space while reducing light interference.
Innovation Solution
The optical sensor module design includes a housing with separate cavities for the optical emitter and sensor, with a conical shape and reflective coating to reduce cross-talk, and positions the sensor unit to shadow the sensor surface from emitter light, eliminating the need for a physical septum between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the optical emitter, optical sensor, and ASIC are arranged closely together to minimize space, then the device size is reduced, but light pollution and cross-talk increase which decreases performance
Solution Approach 1:
The patent positions the optical sensor at a different height (vertical dimension) than the optical emitter, creating a height difference that allows the sensor to shadow its sensitive surface from direct emitter light. This vertical separation resolves the contradiction by maintaining close lateral spacing (reducing footprint) while preventing cross-talk through vertical positioning.
Solution Approach 2:
The patent utilizes the housing structure and component positioning to create shadowing effects that block harmful direct light from reaching the sensor. By strategically positioning the sensor relative to the emitter and utilizing the housing walls, the design converts the potential harm of close proximity (cross-talk) into a benefit (reduced cross-talk through shadowing) without requiring additional light-blocking components.
2Reliability
If a physical septum is added to separate the optical emitter and sensor to reduce cross-talk, then light pollution is reduced, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent employs the optical sensor unit itself to shadow its sensitive surface from direct emitter light. The sensor's own structure and positioning create the necessary light blocking, eliminating the need for separate septum components. This self-service approach reduces device complexity while maintaining cross-talk reduction.
Solution Approach 2:
The patent removes the need for physical septum structures by extracting the light-blocking function and integrating it into the positioning and shadowing geometry of the existing components. The housing walls and component arrangement itself provide the separation function that would otherwise require additional septum elements.
3Reliability
If the optical sensor is positioned to shadow its surface from emitter light, then cross-talk is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The patent establishes the vertical height difference and shadowing geometry during the design and assembly planning phase. By pre-determining the optimal height difference between emitter and sensor positions, the manufacturing process can follow established guidelines rather than requiring ultra-precise real-time adjustments, thereby reducing actual manufacturing precision requirements while maintaining cross-talk reduction.
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 design effectively reduces light pollution and cross-talk, enhancing the sensitivity and performance of the optical sensor module while minimizing its size and manufacturing costs.
Implementation Method 1
The optical sensor unit can be positioned relative to the optical emitter die such that a portion (e.g., a side edge) of the optical sensor unit shadows at least a portion of an optically sensitive surface of the optical sensor die from at least some emitter light that does not exit the housing
Implementation Method 2
The optical emitter die can be configured to emit light towards the first side of the housing
Implementation Method 3
a conical shape and reflective coating to reduce cross-talk
Data Source
AI summary
An optical sensor module is disclosed. The optical sensor module can include a housing comprising an air cavity. An optical emitter die can be disposed in the air cavity of the housing. A top surface of the optical emitter die can face a first side of the housing, the optical emitter die configured to emit light towards the first side of the housing. An optical sensor die can be disposed in the air cavity of the housing adjacent the optical emitter die. The optical sensor die can be spaced from the optical emitter die by a lateral distance. A top surface of the optical sensor die can face the first side of the housing. There may be no septum between the optical sensor die and the optical emitter die that optically separates the optical sensor die and the optical emitter die.