Optical Head Light Detector with Segmented Light Guides
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Solution Overview
Problem
Conventional optical heads face challenges in downsizing while maintaining high recording and reproduction performance, particularly for multilayer optical discs, due to increased stray light interference which degrades focus and tracking error signals, and requires larger apertures that compromise the optical head's dimensions and strength.
Innovation Solution
The optical head incorporates a light detector with a package featuring light guides on the light-receiving surface to guide reflected light and a light shield to prevent stray light, allowing for downsizing and improved signal quality by preventing stray light interference and reinforcing the package structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional aperture is used to block stray light, then stray light interference is reduced, but the optical head size increases and package strength decreases
Solution Approach 1:
The aperture is divided into multiple separate light shielding portions positioned at different locations. Instead of using one large aperture, the patent segments the light blocking function into multiple smaller elements that can be strategically placed to block stray light paths without requiring a large overall aperture structure.
Solution Approach 2:
Light shielding portions are selectively positioned at specific locations where stray light interference occurs most severely. The patent applies light blocking functionality locally at critical points rather than uniformly across the entire aperture area, optimizing stray light rejection while minimizing the overall aperture size.
2Object-affected harmful factors
If a conventional aperture is used to block stray light, then stray light interference is reduced, but package strength decreases
Solution Approach 1:
The aperture is divided into multiple separate light shielding portions positioned at different locations. Instead of using one large aperture, the patent segments the light blocking function into multiple smaller elements that can be strategically placed to block stray light paths without requiring a large overall aperture structure.
Solution Approach 2:
Light shielding portions are selectively positioned at specific locations where stray light interference occurs most severely. The patent applies light blocking functionality locally at critical points rather than uniformly across the entire aperture area, optimizing stray light rejection while minimizing the overall aperture size.
3Strength
If the aperture is enlarged to maintain strength, then package integrity is improved, but stray light interference increases
Solution Approach 1:
The aperture is divided into multiple separate light shielding portions positioned at different locations. Instead of using one large aperture, the patent segments the light blocking function into multiple smaller elements that can be strategically placed to block stray light paths without requiring a large overall aperture structure.
Solution Approach 2:
Light shielding portions are selectively positioned at specific locations where stray light interference occurs most severely. The patent applies light blocking functionality locally at critical points rather than uniformly across the entire aperture area, optimizing stray light rejection while minimizing the overall aperture size.
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 enables the optical head to be downsized while enhancing the quality of focus, tracking, and reproduction signals, maintaining strong package integrity and stable performance.
Implementation Method 1
The package has a plurality of light guides formed on a light-receiving surface on a light beam incident side of the light-receiving unit, and for guiding the reflected light beam to the light-receiving unit
Implementation Method 2
a computation circuit for performing a prescribed computation on an electric signal obtained by photoelectrically transducing a light beam received at the light-receiving unit
Data Source
AI summary
There are provided an optical head and an optical information device capable of downsizing the optical head, and capable of improving the qualities of a focus error signal, a tracking error signal, and a reproduction signal. A light detector (120) includes a light-receiving unit (121) for receiving a reflected light beam from an optical disc, and a package (125) for covering the light-receiving unit (121). The package (125) has a plurality of light guides (124) formed on a light-receiving surface on the light beam incident side of the light-receiving unit (121), and for guiding a reflected light beam to the light-receiving unit (121), and a light shield (114) for shielding a region except for a plurality of the light guides (124) from light.