Optical Pickup Suspension Using Flexible Springs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional focusing and tracking actuators for optical pickup units in optical tape storage machines are bulky, limiting the number of units that can be assembled along a limited length of a tape stabilizer.
Innovation Solution
The use of flexible suspension springs with bends and electro-magnetic actuators allows for the movement of the objective lens housing in both tracking and focusing directions, enabling a narrow profile design that allows multiple optical pickup units to be stacked and aligned along the tape stabilizer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional focusing and tracking actuators are used, then the objective lens can be supported and moved, but the actuator becomes bulky and limits the number of units that can be assembled along the tape stabilizer
Solution Approach 1:
The actuator is divided into separate functional components: permanent magnets are positioned on one side of the lens housing while coils are positioned on the opposite side. This segmentation allows each component to be optimized independently and reduces the overall bulk by distributing magnetic components rather than concentrating them in a single assembly unit.
Solution Approach 2:
The patent transitions from a conventional single-sided magnet arrangement to a dual-sided configuration where magnets are positioned on both sides of the lens housing. This dimensional change allows for more efficient magnetic flux utilization and reduces the required actuator volume while maintaining the same tracking and focusing capabilities.
2Volume of moving object
If the objective lens is positioned using conventional suspension wires, then the lens can be supported, but the overall assembly becomes bulky
Solution Approach 1:
The patent replaces conventional mechanical suspension wires with a magnetic field-based positioning system. Permanent magnets and coils create electromagnetic forces that suspend and position the objective lens without requiring physical wire connections, thereby reducing mechanical bulk while maintaining precise positioning capability.
Solution Approach 2:
The suspension system transitions from mechanical wire tension to magnetic field force balance. By changing the fundamental parameter from mechanical tension to electromagnetic force, the system achieves the same lens suspension function with significantly reduced physical volume and improved integration density.
3Force
If magnets are positioned on both sides of the lens housing, then tracking and focusing forces are improved, but the device complexity increases
Solution Approach 1:
The dual-sided magnet configuration serves multiple functions simultaneously: magnets on one side provide tracking force while magnets on the other side provide focusing force. This multi-functional arrangement eliminates the need for separate magnetic assemblies for each function, reducing overall device complexity despite the increased number of magnetic components.
Solution Approach 2:
The patent merges the tracking and focusing magnetic systems into a single integrated dual-sided magnet assembly. By combining both functional requirements into one unified structure with magnets positioned on opposite sides of the lens housing, the system achieves improved force characteristics without proportionally increasing complexity.
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 enables a higher density of optical pickup units to be integrated along the tape stabilizer, improving the efficiency and compactness of optical tape drive storage machines.
Implementation Method 1
electro-magnetic actuators allows for the movement of the objective lens housing
Implementation Method 2
flexible suspension springs with bends
Data Source
Figure 1~2
Figure 3~5
Figure 6
AI summary
A suspension system is provided for an objective lens housing. The objective lens housing is supported by the suspension system and is moved in either a tracking direction Y or focusing direction Z by an electro-magnetic actuator. The objective lens housing is supported by upper and lower suspension springs. The suspension springs are moveable in the tracking direction by flexing the suspension springs and are moveable in a focusing direction by compressing a front portion and a back portion to fold the suspension spring at bends formed in an intermediate portion of the suspension springs.