Compact Optical Pickup Lens Actuator Design
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Solution Overview
Problem
Conventional optical pickup devices require significant space in the tape running direction, which is a constraint in optical tape storage devices where space is limited.
Innovation Solution
The optical pickup device design includes a lens actuator with a movable portion supported by elastic members and a magnetic field generator, where the objective lens is positioned between specific lines defined by the connections of these members, allowing for compact arrangement and independent focus and tracking control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the wire is secured to the movable portion at two points that are close to both ends in the tracking direction, then the objective lens can be positioned inside the region surrounded with the wire, but the space required in the tape running direction increases
Solution Approach 1:
The patent repositions the objective lens from being surrounded by the wire in the tracking direction to being positioned between the wires in the tape running direction. This dimensional reconfiguration allows the lens to be located in the space between the first and second wires rather than inside the region enclosed by all four wires, thereby reducing the overall space required in the tape running direction while maintaining stable support of the movable portion
Solution Approach 2:
Instead of positioning the objective lens inside the region surrounded by the wire as in conventional designs, the patent inverts this arrangement by positioning the lens between the first and second wires that extend in the tape running direction. This inverted configuration reduces the space requirement in the critical tape running direction while still providing adequate support for the movable portion
2Stability of the object's composition
If the center of mass of the movable portion is aligned with the center of the driving force, then good stability is achieved in focusing and tracking directions, but the device complexity increases
Solution Approach 1:
The patent employs asymmetric positioning of the objective lens relative to the wire connections, where the lens is specifically positioned between the first and second wires in the tape running direction rather than at the geometric center. This asymmetric arrangement, combined with the magnetic field generator configuration, achieves stable focusing and tracking control without requiring complex counterbalancing mechanisms, thereby reducing device complexity while maintaining stability
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 reduces the space required in the tape running direction, enabling a more efficient and compact optical pickup device configuration suitable for optical tape storage devices.
Implementation Method 1
a magnetic field generator that is arranged so as to apply magnetic force to at least part of the movable portion
Implementation Method 2
first and second elastic supporting members that couple the movable portion elastically to the fixed portion
Data Source
AI summary
In one embodiment, an optical pickup device includes a fixed portion 100, a movable portion 11, first and second elastic supporting members 12a and 12b, one and the other ends of which are secured to the fixed portion 100 and the movable portion 11, respectively, and an objective lens 8 secured to the movable portion 11. The objective lens 8 is arranged inside of the area that is defined between two lines that are respectively drawn from one and the other ends of the first elastic supporting member 12a perpendicularly to the first elastic supporting member 12a and outside of the area defined between the first and second elastic supporting members 12a and 12b.