Optical-Electron Hybrid Apparatus for Nanometer Pit Shape Examination
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional information recording medium examining apparatuses cannot accurately examine the shapes of pits on optical disks, which are crucial for recording operations, especially for high-capacity disks with pit dimensions in the nanometer range, and lack precision in defect detection.
Innovation Solution
An apparatus and method utilizing an electron beam to irradiate and examine the surface of information recording media, including a detector for acquiring surface information and an image-producing unit to visualize pit shapes, along with a defect detecting unit using light to identify and position defects for high-precision electron beam analysis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical methods are used to read signals from optical disks, then the examination process is simple and fast, but the precision is insufficient to examine pit shapes at 1 nm level
Solution Approach 1:
The patent combines an optical examination unit and an electron beam examination unit into a single integrated apparatus. The optical unit performs initial defect detection, and the electron beam unit provides high-precision pit shape examination, merging the advantages of both methods while sharing common components like the stage and control system.
Solution Approach 2:
The patent replaces the optical examination system with an electron beam examination system for high-precision pit shape measurement. The electron beam apparatus substitutes the optical readout to achieve 1 nm level precision in examining pit dimensions and shapes.
2Measurement precision
If electron beam examination is used to achieve 1 nm precision, then measurement precision is improved, but examination speed and productivity decrease
Solution Approach 1:
The patent segments the examination process into two distinct stages: first, rapid optical scanning to detect defect positions, and second, targeted electron beam examination of only the detected defect regions. This segmentation allows the majority of the disk to be examined quickly by optical means while applying high-precision electron beam analysis only where necessary.
Solution Approach 2:
The patent performs preliminary optical examination to identify defect positions before conducting electron beam examination. This preliminary action filters out the vast majority of areas that do not require high-precision analysis, preparing a targeted list of regions for subsequent detailed electron beam inspection.
3Reliability
If conventional optical reading is used, then the apparatus is simple to operate, but it cannot detect defect positions accurately for further analysis
Solution Approach 1:
The patent implements a feedback mechanism where the optical examination unit provides defect position information that automatically triggers and guides the electron beam examination unit. The system uses the optical detection results as feedback to control the subsequent high-precision examination, creating a closed-loop examination process.
Solution Approach 2:
The patent introduces an intermediary control system that coordinates between the optical and electron beam units. This intermediary component processes the optical detection data and manages the electron beam examination parameters, serving as a mediator that simplifies the overall operation while enabling accurate defect detection.
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
Enables precise examination of pit shapes and defect detection on optical disks, improving the accuracy of recording operations and enhancing the detection of defects in high-capacity storage media, thereby improving productivity and precision in manufacturing.
Implementation Method 1
an electron gun for irradiating an intended position of the information recording medium with an electron beam; a detector for detecting electrons having acquired information of a surface of the information recording medium by irradiating the information recording medium with the electron beam
Implementation Method 2
a light source for irradiating the information recording medium; a light receiving device for receiving reflection light from the information recording medium
Data Source
AI summary
In an examining apparatus, an electron gun irradiates an intended position of an information recording medium with an electron beam. A stage holds the information recording medium such that the information recording medium can be moved along a rotation direction and a radial direction. A detector detects electrons which have acquired information of a surface of the information recording medium by irradiating the information recording medium with the electron beam. An image producing unit acquires an image of the surface of the information recording medium based on the electrons detected by the detector. The examining apparatus can examine as to whether or not a defect of an information recording medium such as a CD and a DVD is present, but also can examine a shape of the defect thereof. The examining apparatus can also examine an information recording medium having a large storage capacity.