Stacked Ambient Light and Proximity Sensor Module

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Solution Overview

Problem

The integration of ambient light sensors and proximity sensors in electronic devices increases complexity, cost, and size due to their separate modules, which can lead to saturation of infrared photodetectors by ambient light photons.

Innovation Solution

An electronic module is designed with an ambient light sensor stacked over a proximity sensor, utilizing a light guide and interposer to direct infrared photons while blocking ambient light photons, ensuring optical isolation and minimizing module size and cost.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If ambient light sensor and proximity sensor are integrated in separate electronic modules, then each sensor can function independently, but the complexity, cost and size of the apparatus increase

Engineering Contradiction:
Improveindependent sensor functionVSAvoidmodule complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the ambient light sensor and proximity sensor into a single integrated electronic module, merging previously separate functional units. This integration reduces the overall number of components, simplifies the device structure, and lowers cost while maintaining the independent operational capability of each sensor type through shared packaging and electrical interconnections.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The integrated module serves multiple functions simultaneously - it acts as both an ambient light sensing unit and a proximity sensing unit. The shared packaging structure and common electrical interface enable the module to perform multiple sensor functions without requiring separate dedicated modules for each sensing type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If ambient light sensor and proximity sensor are integrated in separate electronic modules, then each sensor can function independently, but the size of the apparatus increases

Engineering Contradiction:
Improveindependent sensor functionVSAvoidmodule size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent implements a nested arrangement where the ambient light sensor is positioned within the same packaging structure as the proximity sensor. Specifically, the ambient light sensor is placed in a first cavity while the proximity sensor occupies a second cavity within the same module housing, allowing one sensor to be effectively nested within the overall module structure containing the other sensor.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The patent utilizes vertical stacking and three-dimensional spatial arrangement to accommodate both sensors within a compact footprint. By arranging sensors in different cavities and layers within the module rather than placing them side-by-side in a single plane, the design efficiently uses available volume and reduces the overall module size.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Quantity of substance

If ambient light photons are not blocked from reference infrared photodetector, then the reference infrared photodetector can receive all photons, but the photodetector becomes saturated by ambient light photons

Engineering Contradiction:
Improvephoton receptionVSAvoidphotodetector performance
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent extracts and removes harmful ambient light photons from reaching the reference infrared photodetector using an ambient light filter. This filter selectively blocks ambient light photons while allowing infrared photons from the infrared photoemitter to pass through, thereby preventing saturation and maintaining reliable photodetector operation.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The ambient light filter acts as an intermediary element positioned between the ambient light environment and the reference infrared photodetector. This intermediate component selectively transmits desired infrared photons while blocking harmful ambient light photons, mediating the interaction between light sources and the photodetector to prevent saturation.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 prevents saturation of infrared photodetectors, maintains unobstructed fields of view, and integrates sensors in a compact, cost-effective manner, suitable for devices like smartphones and cameras.

Implementation Method 1

a light guide arranged between the ambient light sensor and the proximity sensor to convey infrared photons transmitted by the infrared photoemitter toward the reference infrared photodetector

Methodology Applied
Scientific EffectOptical transmission: Light

Implementation Method 2

an ambient light filter arranged to reduce ambient light photons received by the reference infrared photodetector

Methodology Applied
Scientific EffectOptical filtering: Filter (optical)

Implementation Method 3

infrared photons transmitted by the infrared photoemitter

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 4

reference infrared photodetector to receive infrared photons transmitted by the infrared photoemitter

Methodology Applied
Scientific EffectPhotodetection: Photoelectric Effect

Data Source

PatentEP3553563B1Electronic module
Publication Date: 2021.06.16 STMICROELECTRONICS (RES & DEV) LTD
  • EP3553563B1 patent drawingFigure 1~2
  • EP3553563B1 patent drawingFigure 3~4
  • EP3553563B1 patent drawingFigure 5~6

AI summary

The present disclosure relates to an electronic module comprising: an ambient light sensor (34) comprising an ambient light photodetector (38); and a proximity sensor (8) comprising an infrared photoemitter (10), a reference infrared photodetector and another infrared photodetector (14); wherein the ambient light sensor (34) is arranged over the proximity sensor (8) to allow infrared photons transmitted by the infrared photoemitter (10) to be received by the reference infrared photodetector .