Pivoting Arm Sensing Device for Optical Disc Drive Reliability
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Solution Overview
Problem
Optical disc drives face structural damage due to stress concentration in the elastic elements used to deform and move the optical pick-up head, leading to reduced service life.
Innovation Solution
A sensing device design where the arm pivots relative to a pillar, driven by a magnetic or electromagnetic force, allowing the sensing element to move towards the object without relying on structural deformation, thereby reducing stress concentration and extending the service life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If an elastic element is used to deform and move the optical pick-up head, then the optical pick-up head can be pushed towards the optical disc for data pickup, but the elastic element is easy to have structural damage or break due to stress concentration
Solution Approach 1:
The patent replaces the elastic element-based mechanical deformation system with a magnetic field-based actuation system. The driving module uses electromagnetic coils and magnetic elements to generate magnetic forces that directly move the arm along the second axis, eliminating the need for elastic element deformation and thereby preventing stress concentration and structural damage.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the driving module and the arm. The electromagnetic coils generate magnetic fields that interact with magnetic elements to produce forces, serving as a non-contact intermediary that transfers motion without mechanical stress concentration on a single elastic element.
2Productivity
If the elastic element bears the weight of the arm and optical pick-up head while deforming under external force, then the optical pick-up head can be actuated, but the elastic element is subject to stress concentration leading to damage
Solution Approach 1:
The patent substitutes the weight-bearing and actuation function of the elastic element with a rigid arm structure supported by a magnetic field-based driving module. The arm moves along predetermined paths (first and second axes) through magnetic forces, eliminating the need for the elastic element to bear weight and deform under stress.
Solution Approach 2:
The patent transitions from a static elastic element that deforms under load to a dynamic system where the arm can move along multiple axes through controlled magnetic forces. The driving module can independently control movement along the first axis (parallel to supporting surface) and second axis (perpendicular to supporting surface), providing dynamic positioning without stress concentration.
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
The design prolongs the service life of the sensing device by reducing the likelihood of structural damage from stress concentration, while also simplifying the fabrication process and improving sensing efficiency through the use of a piezoelectric sheet to adjust the optical axis.
Implementation Method 1
a magnetic force generated between the electromagnetic coil and the magnetic element drives the arm to pivot relatively to the pillar along the first axis
Implementation Method 2
the piezoelectric sheet is powered and deformed to amend an optical axis inclining angle of the sensing element
Data Source
AI summary
A sensing device including a base, a pillar, an arm, a sensing element and a driving module is provided. The base has a supporting surface suitable for supporting the object. The pillar is disposed on the supporting surface. The arm has two ends and a pivot portion between the two ends. The pivot position is pivoted to the pillar along an axis substantially parallel to the supporting surface. The sensing element is disposed on the arm and located between an end and the pivot portion. The sensing element is located between the base and the object. The driving module is disposed between the arm and the base. The driving module drives the arm to pivot relatively to the pillar along the axis, and the sensing element moves toward or away from the object as the arm is pivoted.