Multi-Wavelength Object Lens with Segmented Diffraction Regions
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Solution Overview
Problem
Existing optical pickups require multiple object lenses and complex optical systems to achieve compatibility with different optical disc formats, leading to issues such as suboptimal lens inclination, increased cost, and reduced sensitivity due to the need for additional optical parts and precise assembly of diffraction units.
Innovation Solution
A single object lens with a diffraction unit having multiple diffraction regions on one face is used to manage optical beams of different wavelengths, ensuring suitable condensation and minimizing spherical aberration for three types of optical discs, thereby simplifying the optical pickup structure and reducing manufacturing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple object lenses are used to achieve compatibility with different optical disc formats, then adaptability is improved, but device complexity increases
Solution Approach 1:
A single object lens is designed to perform multiple functions by supporting different wavelengths (405nm, 655nm, 785nm) through a diffraction unit with multiple diffraction regions. Each region is optimized for specific wavelength combinations, allowing one lens to replace multiple dedicated lenses for different optical disc formats (BD, DVD, CD).
Solution Approach 2:
The diffraction unit is segmented into multiple diffraction regions (first, second, and third diffraction regions) with different diffraction structures. Each region handles specific wavelength combinations, enabling the single object lens to manage multiple optical disc types without requiring separate lenses for each format.
2Adaptability or versatility
If multiple object lenses are used to cover different wavelengths, then adaptability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The single object lens is designed with universal applicability across multiple wavelengths through the diffraction unit. By incorporating multiple diffraction regions with optimized structures for different wavelength combinations (405nm/655nm, 405nm/785nm, 655nm/785nm), the lens achieves multi-wavelength compatibility without requiring multiple separate lenses, thereby reducing the cumulative precision requirements associated with assembling and aligning multiple lenses.
3Adaptability or versatility
If additional optical parts are added for different disc types, then adaptability is improved, but cost increases
Solution Approach 1:
The patent implements a single object lens with an integrated diffraction unit that supports multiple optical disc types (BD, DVD, CD) across different wavelengths. This universal design eliminates the need to manufacture and assemble multiple separate object lenses and associated optical parts, significantly reducing manufacturing costs while maintaining full compatibility with various disc formats.
4Adaptability or versatility
If multiple object lenses are used, then adaptability is improved, but sensitivity decreases
Solution Approach 1:
The diffraction unit is divided into multiple specialized diffraction regions, each optimized for specific wavelength combinations. This segmentation allows each region to be finely tuned for its target application, maintaining high signal sensitivity for each wavelength while still providing multi-format support through the collective functionality of all regions.
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 solution enables efficient recording and playback of signals from multiple optical disc formats using a common object lens, reducing the number of optical parts, lowering costs, and improving manufacturing precision while maintaining high signal quality.
Implementation Method 1
a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams
Data Source
AI summary
An optical pickup includes: a first emitting unit to emit an optical beam of a first wavelength; a second emitting unit to emit an optical beam of a second wavelength; a third emitting unit to emit an optical beam of a third wavelength; an object lens to condense optical beams emitted from the first through third emitting units onto a signal recording face of an optical disc; and a diffraction unit provided on one face of an optical element or the object lens positioned on the optical path of the optical beams of the first through third wavelengths; wherein the diffraction unit includes a generally circular first diffraction region provided on the innermost perimeter, a ring zone shaped second diffraction region provided on the outer side of the first diffraction region, and a ring zone shaped third diffraction region provided on the outer side of the second diffraction region.