GB/Z 18390-2001 Information technology 90mm optical disc cartridge measurement technology guide
Some standard content:
ICS35.220.30
National standardization guidance technical document of the People's Republic of China GB/Z18390-2001
idtISO/IECTR13841:1995
Information technology-Guidance on measurementtechniques for 90 mm optical disk cartridges
Technical guide
Information technology-Guidance on measurementtechniques for 90 mm optical disk cartridges2001-07-16Promulgated
General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China
Implementation on 2002-05-01
GB/z18390—2001
This guidance technical document is equivalent to the international standard ISo/ECTR13841:1995 "Information technology-Guidance on measurementtechniques for 90 mm optical disk cartridges" and is compiled on the basis of the translation of this international standard through analysis and research and standardization of vocabulary and format.
When adopting international standards, some typos and errors in the original international standard texts are corrected. Appendix A, Appendix B, Appendix C, Appendix D, Appendix E, Appendix F, and Appendix H of this guidance technical document are standard appendices; Appendix G is a suggestive appendix.
This guidance technical document is proposed by China Aviation Industry Corporation. This guidance technical document is under the jurisdiction of the National Information Technology Standardization Technical Committee. The drafting units of this guidance technical document: Beijing University of Aeronautics and Astronautics, University of Electronic Science and Technology of China. The main drafters of this guidance technical document: Wang Rui, Rong Lun, Ge Qihan, Zhang Ying. I
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GB/Z18390—2001
ISO/IEC Foreword
ISO (International Organization for Standardization) and IEC (International Electrotechnical Commission) form a worldwide specialized system of standardization. Member countries of ISO or EC participate in the development of international standards through technical committees established by various organizations dealing with special technical activities. ISO and IEC technical committees collaborate in areas of common interest. Other international organizations, both governmental and non-governmental, in liaison with ISO and IEC, also participate in this work.
In the field of information technology, ISO and IEC have established a joint technical committee ISO/IEC JTC1. The main task of technical committees is to prepare international standards, but in special cases, a technical committee may propose the publication of a technical report in one of the following forms:
- Form 1, when despite repeated efforts, the necessary support is not obtained for the publication of an international standard.
- Form 2, when the subject is still at a stage of technical development or for any other reason, it is likely that agreement on an international standard will be reached in the future rather than immediately.
- Form 3, when a technical committee collects different kinds of data (e.g. "state of the art") from publications that are normally published as international standards.
Technical reports in Forms 1 and 2 are reviewed within three years of publication to determine whether they can be transformed into international standards. Technical reports in Form 3 do not need to be reviewed unless the data they provide is considered no longer valid or useful. ISO/IEC TR13841 is a form 3 technical report prepared by the Information Technology Subcommittee of the Joint Technical Committee of ISO/IEC JTC1.
1 Overview
National Standardization Guidance Technical Document of the People's Republic of China Information Technology 90 mm Optical Disk Cartridge Measurement
Technical Guide
Information technology Guidance on measurement techniques for 90 mm optical disk cartridges1.1 Scope
GB/Z18390—2001
idtIS0/IECTR13841:1995
This guidance technical document provides guidance on measurement techniques for 90 mm rewritable/read-only optical disk cartridges. 1.2 Purpose
The guidance on measurement techniques provided by this guidance technical document is not yet well understood by the industry. The purpose of this guidance technical document is to help relevant personnel understand the compatibility between disks and drives and the interchangeability between disks and drives. This guidance technical document provides some measurement examples and measurement technology guidance in these aspects. 1.3 Referenced standards
The clauses included in the following standards constitute the clauses of this guidance technical document by being referenced in this guidance technical document. When this guidance technical document is published, the versions shown are valid. All standards will be revised, and the parties using this guidance technical document should explore the possibility of using the latest versions of the following standards. GB/T17234-1998 Information Technology Data Exchange 90mm Rewritable/Read-Only Cartridge Optical Disk (idtISO/IEC10090.1992)
1.4 Definitions
The definitions of this guidance technical document are exactly the same as those of GB/T17234. 2 Measurement Environment
2.1 Overview
This guidance technical document provides three measurement environments. In each clause of Chapter 5, one of the three measurement environments defined below may be referenced. Unless otherwise specified, measurement environment A can basically be used for each clause in Chapter 5, and other additional measurement environments or conditions will be introduced in the items that appear.
2.2 Measurement environment A
Measurement environment A is the same as the test environment specified in GB/T17234. Temperature: 23℃±2℃
Relative humidity: 45%~55%
Atmospheric pressure: 60kPa～106kPa
Purification level: Class 100000
Magnetic field strength 32000A/mmax.
2.3 Measurement environment B
Measurement environment B is used for the measurement of the highest temperature boundary area. Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on July 16, 2001-KAONiKAca-
Implemented on May 1, 2002
Temperature: 50℃±2℃
Relative humidity: No special requirements
Atmospheric pressure: No special requirements
Purification level: Class 100000
Magnetic field strength: 32000A/mmax.
2.4 Measurement environment C
GB/Z18390—2001
(Unless otherwise specified)
Measurement environment C is used for testing in different temperature ranges. The test environment range value is the same as the operating environment specified in GB/T17234. Temperature: 5℃±2℃, 23℃±2℃, 50℃±2℃Relative humidity: no special requirements
Atmospheric pressure: no special requirements
Purification level: 100000 level
Magnetic field strength 32000A/mmax.
3 Measurement setup
3.1 Overview
(Unless otherwise specified)
The drive used to measure the disc should be calibrated before measuring the disc. A typical calibration disc suitable for laser power calibration is described in 3.3.
3.2 Measurement accuracy
The measurement device should have high reproducibility and repeatability. The recommended operating tolerance rate (P/T) is: P/T = 6*SD/T<0.2
Where: SD standard deviation;
T-tolerance, its value is the difference between the upper and lower limits in the technical specification. Taking reflectivity as an example:
P/T=6*SD/(0.29-0.14)<0.2, that is, 8D<0.005. In the case where only a single-sided value defines the specification, the system should be able to distinguish the number of important figures in the parameter specification. 3.3 Calibration disk
The laser power of the optical drive and/or measuring device in the recording layer can be calibrated by the calibration disk. Note: This calibration cartridge CD can be provided by the Reliability Center of Electronic Components of Japan (RCJ), whose address is: RCJ, 1-1-2 Hachiman Higasshikurume Tokyo, Japan, and can be ordered under the number JCM6272 before 2002. 3.4 Measurement area
Unless otherwise specified, GB/T17234 requires that the optical disc should meet the technical specifications over the entire disc area (see Appendix R of GB/T17234-1998). This guidance technical document points out the most critical measurement area in the following items: (A) For read power, narrowband signal-to-noise ratio, sector header signal (I, Ianax/amm), push signal and cross-track signal in the ROM area, the most critical measurement area is the innermost circle of the optical disc (R=24mm). (B) For write power and erase power corresponding to control track data (R=24mm, 30mm, 40mm). (C) For tilt, axial and radial acceleration, the most critical measurement area is the outermost circle of the optical disc (R=40mm). (D) For the reflectivity of the disc, the imbalance of the MO signal, the most critical measurement area is the innermost and outermost rings of the disc (R=24mm, 40mm)
(E) In the measurement area and control area of the inner and outer rings of the disc, the signals obtained from the groove and sector headers are measured. 3.5 Reference servo
GB/T17234 stipulates that the rotation frequency of the disc is 30Hz under the measurement conditions, and stipulates the transfer function of the reference servo for axial and radial tracking of the recording layer (see 9.5 and 11.4 in GB/T17234-1998). When measuring the signal, the radial guidance error between the focus of the light beam and the center of the channel is much smaller than when measuring the radial acceleration. This is achieved by the strong servo provided by 2
GB/Z18390-2001
GB/T17234-1998, 20.2.4. Therefore, the 0.1μm radial addressing error value should increase when it is lower than the acceleration boundary frequency, and should remain unchanged in the frequency range above the acceleration boundary frequency. Various strong servos can be realized by various phase compensators. If the same compensator (C=3) is used as the reference servo, the zero boundary frequency of this strong servo with a rotation speed of 30Hz is 1500Hz, and the acceleration boundary frequency of this strong servo is 870Hz. Table 1 lists the corresponding values of other rotation speed frequencies. Table 1 Constant table for measuring servo
Used for examination of zero boundary
Intermediate servo frequency
Low frequency acceleration
Note: The value of the shaded part is calculated from the reference servo, 4 Measurement technology items
4.1 Overview
Signal servo example
Central boundary frequency
Acceleration
The measurement item table in 4.2 gives the situation of each item. The table divides the items into two groups, namely: (1) Guidance on definitions and measurement techniques
(2) Guidance on measurement techniques.
4.2 Table of measurement items
Chapter number in GB/T17234
24.3.2/24.4.1
5 Measurement technology
5.1 Shutter opening force
5.1.1 Definition
Shutter opening force
Clamping force
Radial and axial acceleration
Reflectivity
Centering column
Groove signal
Sector header signal
Read power
Write power and erase power
Unbalance of MO
Narrow-band signal-to-noise ratio
Grouping
Chapter number
The shutter opening force is defined as the maximum force value of the sum of the weight of the shutter and the friction between the disk box and the shutter when opening and/or closing the shutter. The force is measured in the direction parallel to the shutter movement when the shutter is pushed or pulled. However, the friction generated by the shutter opener in the drive mechanism is not included in the definition.
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5.1.2 Measurement process
GB/Z18390-—2001
Figure 1 shows a method of measurement using a tensiometer. This measurement method does not include the shutter mass, so the shutter mass value should also be added to the measurement result. Another measurement method and measurement data are shown in Appendix H. Box
Tensiometer
Model: 1eclockDT-1000
Figure 1 Example of measurement device
5.2 Holding force
5.2.1 Introduction
The range of the maximum permissible force refers to the force used by the loading motor or mechanical device from clamping a disk without mechanical damage to removing the disk. The clamping force is verified by a disc that meets the upper and lower limits of the disc hub specified in Appendix K of GB/T17234-1998. This item is determined by the drive designer.
5.2.2 Measurement process
(1) Prepare a piece of magnetic material for the disc hub to provide a force of 4.5N to adsorb it on the measuring instrument specified in Appendix K of GB/T17234-1998.
(2) Fix the material on a non-magnetic disc hub and ensure that the height value including the disc base and the material is (1.2±0.01) mm. (3) Clamp the disc on the turntable of the measuring instrument. (4) Measure the clamping force by pulling out the disc. 5.3 Tilt Angle
5.3.1 Introduction
In GB/T17234, the tilt angle is defined as the angle between the reference surface and the incident surface of the disk. In actual measurement, when the reflected light from the recording surface is used, the thickness of the disk substrate must also be considered. There are many methods for measuring the tilt angle. This guidance technical document provides the following two measurement methods. The first method is the same as the method described in GB/T17234, that is, the tilt angle is measured directly with parallel light. The second method is to use a special optical head for measuring physical properties to measure the tilt angle. 5.3.2 Measurement Method 1
This method has been used for a long time, and its measurement principle is shown in Figure 21. When we use a low-power He-Ne laser as the light source, the diameter of the light spot used for measurement is about 1mm, so this method is very similar to the definition in GB/T17234. In this measurement method, we should also consider the following conditions:
(A) When measuring the outermost area of the disk, the light spot diameter should be controlled within the range of 1mm. (B) When the inclination angle increases, the increase in error depends on the thickness of the disk substrate. Adoption instructions:
1] In ISO/IEC TR13841, this is Figure 3. In this guidance technical document, it is changed to Figure 2 according to the context. 4
5.3.3 Measurement method 2
GB/Z18390—2001
This is a method for measuring the inclination angle by axial deviation value. In order to measure the axial deviation, the position of the objective lens is either detected by a specially designed optical head with a micro sensor or by measuring the current value of the objective lens actuator. These methods are more convenient than measurement method 1 because they can also measure other mechanical properties at the same time. The principle of the method of measuring the inclination angle using the axial deviation value is shown in Figure 31. Assuming that there is a square plane of several square millimeters, the radial inclination angle (m) or the tangential inclination angle (m) can be calculated by the difference between two axial separation points (A1, B or A2, A,) and the value of the distance (l. or 1). Tangential inclination angle:
Radial inclination angle:
Then, the composite angle (inclination angle) is,
Inclination angle:
Axial deviation Dg
Explanation:
po=tan-1(△do/to)
-tan-1((DA1 - DA2)/1,2)
=tan-1(△dr/1,)
-tan-1((D A1 - DB)/t,)
=十）
Spot size ~1.0 mm
Half-reverse lie,
Huanguang Tour
Position sensor
Direct measurement of inclination (measurement method 1)
Reference surface of the disc
Figure 3 Measurement of inclination by axial deviation (measurement method 2) 1In ISO/IECTR13841, this is Figure 2, which is changed to Figure 3 in this guidance technical document according to the context. 2］In ISO/IECTR13841, this is l, which is changed to lo in this guidance technical document according to the context. 5
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Caution should be exercised when using the above formula for the following reasons: (A) The inclination value is determined by the axial deviation of two different points, so the estimated value has a great dependence on the accuracy of the distance between the two points. That is: the distance between the two different points is 1. ,,) is smaller, the greater the estimation error is. On the contrary, when the distance between two different points is large, the surface roughness will affect the measurement accuracy. Therefore, the measurement conditions must be carefully considered (B) to measure the inclination angle for every 1mm spacing. The axial deviation value of 5μm should correspond to 5mrad in the specification. Therefore, the measurement accuracy cannot be ignored. 5.4 Axial and radial acceleration
5.4.1 Introduction
GB/T17234 assumes that the light spot tracks the channel of the disc with the help of axial and radial servo mechanisms. The tracking accuracy must exceed the requirements of the reading accuracy, but the axial and radial movements may become an obstacle to achieving tracking accuracy. At low frequencies, the servo system responds, the objective lens tracks the movement of the disc and the servo loop gain reduces a part of the distance between the light spot and the channel, which means that the disc moves faster during tracking. On the other hand, at high frequencies, the servo system does not respond, and the disc responds to the tracking activity with its own movement. As a typical servo characteristic of optical disc drives, for those frequency values that rise to the pre-corner frequency range in the phase compensation filter in the loop, there will be a loop gain of 25%. Similarly, when the disc moves sinusoidally under the condition that the maximum acceleration is constant, the relationship between frequency and amplitude is: doubling the frequency will produce a 25% increase in amplitude. Therefore, since the servo gain and disc acceleration have been determined, the tracking acceleration can be estimated at low frequencies (see Figures 4 and 5). Accordingly, if we consider only the acceleration of the disk at low frequencies and only the displacement of the disk at high frequencies, then the tracking of the light spot on the track can be determined to some extent. However, if we try to establish an accurate rule for the above situation, we will find the following problems: first, it is very complicated to measure the two physical quantities of acceleration and displacement independently of the frequency. Second, the excess movement of the objective lens near the zero-crossing frequency cannot be accurately known through acceleration and displacement. For example, Figure 4 shows that an acceleration of 17.5m/s is allowed at a loop gain of 600Hz, while only 0.8μm of disk movement is allowed at a loop gain of 1000Hz. From the above considerations, GB/T17234 stipulates the servo deviation specification using the inherent characteristics of the reference servo. The reason for choosing this specification is that the servo deviation can appear directly during the tracking movement, and then this physical quantity can be estimated over the full frequency range. 400F
ai/period
acceleration
frequency/H2
maximum acceleration: 10m/g
FO: 870 Hz
acceleration call value: 17.5ms
residual error 1 μm
Servo loop gain
Figure 4 Ratio of acceleration to servo loop gain
'ititt
TTTning
Deviation/μm
Acceleration/n/s
Residual error/m
Deviation/um
Acceleration/m/s2
Residual error/μm
5.4.2 Measurement system
GB/Z18390—2001
Case A: When the disc has only the low-frequency component of the axial deviation, the axial deviation/μm
Axial acceleration/m/s2||tt| |Axial tracking error/um
Case B: When the disk has high and low frequency components of axial deviationAxial deviation/μm
Axial acceleration/m/s
Axial tracking error/μm
Figure 5 Simulation of mechanical characteristics of disk
Figure 6 shows the measurement system (this figure is a combination of Figure C2 and Figure C4 in the appendix of GB/T17234). In Figure C2, the output of the non-contact electrostatic capacitance sensor is added to the actual servo error signal, and the result is input to the filter with reference servo transmission characteristics. Typical non-contact sensors are generally not easy to achieve accurate measurement from low frequency to high frequency. It is generally believed that operation below 1kHz is satisfactory. Therefore, the movement of the objective lens exceeding the disk movement near the zero crossing frequency of the servo cannot be compensated by the output of the non-contact sensor even if it appears on the error signal, so the measurement accuracy is reduced. In Fig. C4, the actual servo transfer function is indicated and the servo error signal 7
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is input to a filter whose characteristic represents the product of the reference servo transfer function and the inverse of the actual servo transfer function. However, it is generally difficult to accurately measure the transfer function of a servo system from high frequency to low frequency. In particular, for a spring leaf type actuator, the resonance frequency generated by the mass of the spring and the moving part of the actuator is several tens of Hz, and it is not easy to accurately identify its characteristics. Even for a slide type actuator, it is not easy to well identify its characteristics at low frequencies due to the large influence of the slide rod and the slide stroke. For these reasons, we recommend a system whose output uses Fig. C2 at low frequencies and Fig. C4 at high frequencies, so that accurate measurements can be made in both low and high frequency bands without being affected by the frequency. Here, the already installed crossover filters with opposite characteristics are used, which are first-order filters with a cutoff frequency of 600 Hz. In addition, since the objective lens movement can be directly measured at low frequencies, the low-frequency components of the disk movement are stored in the memory and will be used for the feed control of the actual servo system. G1 is a unit of the sensor system with a transfer function of 100kHz frequency band. G2 and G3 are the servo loop phase compensation unit and the actuator transfer function unit, respectively. Their characteristics depend on the type of device used. Batch
Objective lens movement
Sensor
Low-pass filter
Actuator
Compensator
5.4.3 Process 1: Low-pass measurement system
Error sensor
Variable gain
Amplifier
Figure 6 Measurement systembzxz.net
la) Calibrate the non-contact sensor gain.
1b) Measure the error signal gain:
Method A (Axial gain)
Stop the disk.
Turn off the axial and radial servos.
Shangtong filter is Xin
Use a mechanical slow motion device to roughly move the disk and place the disk near the center of the axial error signal e. -Use a piezoelectric element to slowly move the disk and find the center of the axial error signal e. -When the difference between the axial servo signals in the land and the groove becomes large, start the radial servo. -Use a piezoelectric element to move the disk from the center of the error signal by ±1μm and measure the gain at these points. Method B (axial gain)
Stop the disk.
Start the axial and radial servos. When applying a bias voltage to z, use an electrostatic capacitance non-contact sensor to detect the movement of the objective lens and measure the gain at 1μm.
Method C (radial gain)
Stop the disk.
Start the axial servo.
GB/Z18390—2001
-Add chopper to the radial actuator to make it move. For the radial error signal e, obtain a waveform with a deviation of two adjacent cycles within 3%, and consider one cycle as 1.6μm, and measure the gain at ±0.1um from the center of the table. Note that if the cross-track signal is observed at this time, the table and groove can be identified. Method D (Radial Gain)
Stop the disk.
Start the axial and radial servos. When the bias voltage reaches 0, use the electrostatic capacitance non-contact sensor to detect the movement of the objective lens and measure the gain at 1um.
1c) Adjust the variable gain AMP to match the error signal of the non-contact sensor. If method B can be used for gain measurement, it is recommended to input a 100Hz sine wave to z and adjust the variable gain so that the signal becomes 0. 1d) Complete a reference servo analog filter. In order to make the 1/(1+H.) filter accurately simulate the low-pass characteristics, although the digital filter has a relatively simple structure, we generally prefer analog filters. Figures 7 and 8 show examples of analog filters for axial and radial directions, respectively. Figures 9 and 10 are the simulation results of these two filters. 1e) Complete a low-pass filter. The first-order filter as the boundary requires a cutoff frequency of 600Hz. The cutoff frequency and gain here must be consistent with the high-pass filter of the high-pass measurement system with an accuracy of 3%. Note: When the disk is not rotating and the measurement is performed, a low-power laser can be used to avoid damaging the irradiated part of the plastic disk base. 5.4.4 Process 2: High-pass measurement system
2a) Gain of the sensor system:
Adjust the variable gain AMP like the low-pass measurement system. 2b) Transfer function deviation:
Apply an excitation signal from z and measure the transfer characteristic from z to e:ea/z=1/(1+Gi×G2XGs)=1/(1+H.) The cutoff frequency of the high-pass filter in the high-pass measurement is 600 Hz, so the measurement system should operate in the frequency range above 200 Hz. The transfer function is determined by using the transfer characteristic obtained by the curve fitting function of the FFT analyzer. Note: Considering the wide measurement frequency range, the measurement accuracy can be improved by gradually changing the amplitude of the excitation signal in each frequency range in a step-by-step manner. In the measurement, it is important to ensure that no part of the servo loop is saturated. 2c) Complete the (1+H,)/(1+H.) correction filter. 2d) Complete the high-pass filter:
The first-order filter as the crossover band requires a cutoff frequency of 600 Hz. The cutoff frequency and gain here must be consistent with the low-pass filter of the low-pass measurement system with an accuracy of 3%. Gong Lan Di
TLO8IC
TLOB1C
0. 027 μ
Figure 7 Example of 1/(1+H,) filter used in the axial direction -KANiKAca-
TL081C
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