Optical Scanner Module Interconnect Crosstalk Reduction

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Solution Overview

Problem

Conventional optical scanner modules experience cross-talk between sensor interconnects and drive interconnects, leading to inaccurate signal detection due to complex interconnect layouts, which can result in defects even if the mirror fails to oscillate.

Innovation Solution

The optical scanner module incorporates a GND interconnect between sensor and drive interconnects in each layer, and ensures a distance of at least 0.05 mm between them to reduce mutual capacitance and inductance, with non-overlapping and perpendicular configurations to minimize electromagnetic induction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If sensor interconnect and drive interconnect are drawn in the package in a complicated manner, then the module can be compact, but cross-talk is generated between the interconnects causing signal detection inaccuracy

Engineering Contradiction:
Improvepackage sizeVSAvoidsignal detection accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

A GND interconnect is introduced as an intermediary element between the sensor interconnect and drive interconnect. This ground interconnect acts as a shield that reduces electromagnetic coupling and cross-talk between the signal-carrying interconnects, thereby improving signal detection accuracy while maintaining the compact package layout

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The solution transitions from a two-dimensional planar layout problem to a three-dimensional stacked configuration. By arranging sensor and drive interconnects in different layers with vertical stacking, the patent reduces in-plane interference while managing crosstalk through the added vertical dimension using GND shielding layers

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

2Area of stationary object

If the distance between sensor interconnect and drive interconnect is reduced, then the package area is minimized, but mutual capacitance and inductance increase causing cross-talk

Engineering Contradiction:
Improvepackage areaVSAvoidcross-talk
Core Design Contradiction:
Area of stationary objectVSObject-affected harmful factors

Solution Approach 1:

The GND interconnect serves as a protective intermediary that enables closer spacing of sensor and drive interconnects. By placing ground shields between them, the patent reduces mutual capacitance and inductance effects, allowing minimization of package area without sacrificing performance

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent applies different design qualities to different regions: GND interconnects are strategically positioned in close proximity to sensor and drive interconnects to provide localized shielding, while maintaining larger spacing in other areas. This selective approach minimizes cross-talk only where necessary, optimizing overall package area

Inventive Principle:
Principle #3Local quality

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 significantly reduces cross-talk by 75% in the horizontal direction and 84% in the vertical direction, ensuring accurate detection of sensor signals and preventing false defect detection.

Implementation Method 1

non-overlapping and perpendicular configurations to minimize electromagnetic induction

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

ensures a distance of at least 0.05 mm between them to reduce mutual capacitance and inductance

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 3

ensures a distance of at least 0.05 mm between them to reduce mutual capacitance and inductance

Methodology Applied
Scientific EffectInductance: Inductor

Data Source

PatentEP3346312B1Optical scanning module and optical scanning control device
Publication Date: 2022.07.13 MITSUMI ELECTRIC CO LTD
  • EP3346312B1 patent drawingFigure 1
  • EP3346312B1 patent drawingFigure 2
  • EP3346312B1 patent drawingFigure 3

AI summary

The present invention is to provide an optical scanner module capable of reducing cross-talk generated between a sensor interconnect and a drive interconnect. An optical scanner module, includes an optical scanner apparatus that scans incident light by oscillating a mirror; and a package on which the optical scanner apparatus is mounted, wherein the optical scanner apparatus includes a displacement sensor that detects an oscillation angle of the mirror, wherein a sensor interconnect (PS) connected to the displacement sensor and a drive interconnect through which a drive signal for oscillating the mirror passes are respectively drawn from the optical scanner apparatus into the package, wherein interconnect layers (L1, L2) in which the sensor interconnect and the drive interconnect (PD) are formed are stacked, wherein the sensor interconnect and the drive interconnect are placed not to overlap in a plan view of the interconnect layers, and wherein a GND interconnect (PG) is provided between the sensor interconnect and the drive interconnect that are adjacent in a same interconnect layer.