JPH06160406A - Method and instrument for measuring linear velocity and disk used therefor - Google Patents

Abstract

PURPOSE:To simplify the constitution of a linear velocity measuring instrument so as to reduce the cost of the instrument by measuring the linear velocity of an object to be measured from the radial position and rotating speed of the object obtained by means of one detecting section based on a simple principle. CONSTITUTION:A fan-shaped pit section 12 in which pits or slits are arranged in rows in parallel with one-side radial line of a disk 10 for measuring linear velocity is provided on the disk 10 and the disk 10 is rotated. While the disk 10 is rotated, part of the disk 10 at a radius (r) is irradiated with a laser beam, etc., so that the laser beam forms a locus (m) shown by the arrow and reflected light is detected. Thus one-round quantity of scanning signals is obtained. Then the rotating speed (f) of the disk 10 is found from the time t1 required for obtaining the one-round quantity of signals, time t2 required for passing through the pit or slit row section in the fan-shaped pit section 12, and number (n) of pulses detecting pits in the section 12. In addition, the radius (r) of the scanned locus (m) is found from the number (n) of detected pulses. Then the linear velocity (v) of the disk 10 is found from the found rotating speed (f) and radius (r) based on an expression v=r.2pif.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear velocity measuring method, a linear velocity measuring device, and a disk for use in an optical disc master exposure device or the like to calculate a linear velocity from the measured rotation number and radius value.

[0002]

2. Description of the Related Art Conventionally, in an optical disk master exposure apparatus or the like, a glass master is irradiated with a laser beam from an optical system to form land or groove information which is information such as images and music. In this case, the glass master is rotationally driven at CLV (linear velocity). Therefore, it is necessary to know the linear velocity in order to accurately form constant land or groove information. FIG. 8 is a side view showing a configuration of an optical disk master exposure apparatus capable of measuring linear velocity. In this optical disk master exposure apparatus, a glass master 1 is placed on a turntable 2. Then, the laser light is irradiated onto the glass master 1 from the pickup 3 arranged at the fixed position, and is rotated by the motor 4. At the same time, by the transverse feed motor 5 and the air slider 6, this whole is moved laterally, and the pickup 3 is picked up on the glass master 1.
The laser light from is emitted in a spiral shape. further,
The rotary encoder 7a attached to the motor 4 rotates, and this rotation is detected by the rotation speed signal detector 7b. At the same time, the amount of lateral feed is detected by the magnet scale 8a and the position signal detector 8b. As described above, in the conventional optical disk master exposure apparatus, the rotary encoder 7a and the rotation speed signal detection unit 7b detect the rotation amount, and the magnescale 8a and the position signal detection unit 8b detect the lateral feed amount. That is, the linear velocity is measured by the combination of the two detection units. In FIG. 8, 10 is a rotation speed measuring unit, and 11 is a radial position measuring unit.

[0003]

Therefore, the conventional optical disc master exposure apparatus has a drawback that two detecting portions are required for controlling the linear velocity, which complicates the configuration.

The present invention solves the drawbacks of the prior art as described above, and firstly provides a linear velocity measuring method capable of measuring the radial position, the rotational speed and the linear velocity by a simple method. To do. A second object of the present invention is to provide a disk for linear velocity measurement that enables highly accurate measurement of radial position, rotational speed and linear velocity with a simple configuration. A third object is to provide a linear velocity measuring device capable of accurately measuring the linear velocity from the radial position and the number of revolutions obtained by one detection unit, simplifying the configuration, and reducing the cost.

[0005]

In order to achieve this object, in the linear velocity measuring method according to claims 1 and 2, which corresponds to the first object, light is emitted from a fixed position as the disk to be measured rotates. The reflected light or transmitted light that is obtained is electrically converted, and the radius value of the scanning locus is obtained from the number of pulses included in the electrically converted pulse train, and the time of the pulse train or one rotation time of the measured disk that is between the start or end of the pulse train. The rotation speed of the measured disk is calculated from. Further, the linear velocity of the light-irradiated portion of the measured disk is obtained from the rotation speed and the radius value.

According to the disk for linear velocity measurement of claims 3 and 4, which corresponds to the second object, in order to obtain the radius value of the scanning locus of at least one rotation, the disk is parallel to one of the radial lines and is reflected by the surrounding disk member. The lands having different rates, the groove rows, or the slits penetrating the disk member are provided in a fan shape from the center point of the disk member toward the outer side. Further, a plurality of fan-shaped lands, groove rows, or slit rows are provided without overlapping both ends of the lands, grooves, or slits.

According to the linear velocity measuring device of the fifth aspect corresponding to the third object, a land or groove array is formed in a fan shape from the center point of the disk member toward the outer side and is arranged in parallel with one radial line. Alternatively, a linear velocity measuring disk having a slit array, a rotating means for rotating the linear velocity measuring disk together with at least the measured disk, and a land or groove array or slit array of the linear velocity measuring disk are irradiated with light and receive light. And linear velocity signal detection means for obtaining a photoelectrically converted pulse train signal, and when the light from all lands or grooves or all slits obtained by the linear velocity signal detection means is electrically converted, the number of pulses included in the pulse train The radius value is measured, and the number of revolutions of the measured disk is measured from the time of the pulse train or from one rotation time of the disk for linear velocity measurement between the start and end of the pulse train. As a configuration including a rotation speed / radius value measuring means, and a linear speed calculation means for calculating at least the linear speed of the disk to be measured rotated by the rotation means from the rotation speed and radius value obtained by the rotation speed / radius value measuring means There is.

[0008]

As is apparent from the above description, claims 1 and 2
In the linear velocity measurement method, the radius value of the scanning locus is obtained from the number of pulses included in the pulse train, and the number of revolutions of the measured disc is calculated from the time of the pulse train or one rotation time of the measured disc that is between the start or end of the pulse train. Ask. Further, since the linear velocity of the light-irradiated portion of the measured disk is obtained from the rotational speed and the radius value, the radial position, the rotational speed and the linear velocity can be measured by a simple method.

In the disk for linear velocity measurement according to claims 3 and 4, in order to obtain the radius value of the scanning locus of at least one rotation, the land or the groove array or the slit penetrating the disk member is located from the center point of the disk member. It is provided in a fan shape in the outward direction. In addition, multiple fan-shaped lands, groove rows, or slit rows are provided without overlapping both ends of the lands, grooves, or slits, so it is possible to measure the radial position, rotational speed, and linear velocity with high accuracy with a simple configuration. become.

In the linear velocity measuring device according to the present invention, the radius value of the scanning locus is measured from the number of pulses, and from the time of the pulse train or from one rotation time of the linear velocity measuring disk between the start portion and the end of the pulse train. Since the rotational speed of the measured disk is measured and the linear velocity of the rotating measured disk is calculated from this rotational speed and radius value, the linear velocity can be calculated from the radial position and rotational speed obtained by one detector. The measurement can be performed with high accuracy, the configuration can be simplified, and the cost can be reduced.

[0011]

Embodiments of the linear velocity measuring method, the linear velocity measuring device and the disk thereof according to the present invention will be described in detail with reference to the drawings. FIG. 1 is a diagram for explaining an embodiment of the linear velocity measuring method of the present invention. In FIG. 1, a linear velocity measuring disk 10 that rotates together with a master such as an optical disk master exposure device has lands or groove rows or slit rows arranged parallel to one radial line from the center point of the disk member toward the outside. Fan-shaped (1/4 of surface 10 of linear velocity measurement disk)
The land / groove portion 12 formed in the above is provided. When the linear velocity measuring disk 10 rotates, a laser beam or the like is emitted with a radius r as shown by the locus of an arrow m, and scanning for detecting the reflected laser beam is performed. For the irradiation and detection of the laser light, it is preferable to use an optical disk master exposure device described below. This reflected light is detected by the optical system of the optical disk master exposure device, and a signal obtained by scanning one rotation is output from the detection unit. At the same time, a pulse train signal obtained by scanning the land / groove portion 12 is output.

FIG. 2 is a waveform diagram showing a pulse train signal in this embodiment. In FIG. 2, t ₁ is the time for one rotation of the locus of the arrow m, and t ₂ is the fan-shaped section of the land / groove portion 12 in one rotation of the locus of the arrow m, that is, only the land, the groove row, or the slit row is passed. It's time to do it. n is the number of pulses when the land or groove of the land / groove portion 12 is detected. In this case, the rotational speed f of the linear velocity measuring disk 10 is known as f = 1 / T, that is, t ₁ or t _2.
Can be obtained from Here, the detected pulse number n
Varies with the scanned radius r. Therefore, if the number of pulses n is counted, the radius r of the locus scanned by the linear velocity measuring disk 10 can be obtained. The linear velocity v can be obtained from the rotational speed f and the radius r by the well-known formula (1) below. v = r · 2πf (1)

Next, the land / groove portion 12 provided on the linear velocity measuring disk 10 will be described. FIG. 3A is a cross-sectional view showing a land row provided in the land / groove portion 12 and states of incidence and reflection of laser light. On the surface of the linear velocity measuring disk 10, lands 14a, 14b, 14c, 14d as a land row arranged in parallel with one radial line are formed by sputtering or vacuum-depositing a metal film. When laser light is incident on the surface of the linear velocity measuring disk 10, the reflectance of the incident / reflected light Pa on the lands 14a to 14d is higher than the reflectance of the incident / reflected light Pb on the surface. Therefore, by detecting the pulse train signal having a high reflectance and counting the number of pulses n thereof, the radius r of one rotation of the linear velocity measuring disk 10 at the arrow m can be obtained.

On the other hand, FIG. 3B shows grooves 16a, 16b and 16c formed in the lands 14a to 14d of FIG. 3A. The incident / reflected light Pd on the grooves 16a to 16c has a low reflectance, and the incident / reflected light Pc on the surface outside the grooves 16a to 16c has a high reflectance. Therefore, it is possible to detect the pulse train signal having a low reflectance, count the number of pulses n thereof, and obtain the radius r of one rotation of the linear velocity measuring disk 10 at the arrow m. Incidentally, the lands 14a to 14
Instead of the d and the grooves 16a to 16c, slits may be provided parallel to the radial lines. It should be noted that the land or groove of the metal film shown in FIGS. 3A and 3B can form a higher density line,
High resolution can be obtained. In addition, the groove 1 of FIG.
6a to 16c can be formed by a stamper. Therefore,
Mass production is possible.

FIG. 4 is a plan view showing a state in which a 1/4 land / groove portion 19 is formed in addition to the land / groove portion 12 on the linear velocity measuring disk 10. In FIG. 4, this example shows a land
A fan-shaped quarter land / groove portion 19 having a land or groove that does not intersect with the land or groove at the end of the groove portion 12 is formed. The lands / grooves 12 and the lands / grooves 19 are arranged so that one ends of the lands or grooves are aligned with the diameter line L. These two lands and grooves 12, 19
As described with reference to FIG. 1, when scanning is performed along the locus of the radius r and the arrow m, two pulse train signals are output by this one-rotation scanning. Therefore, since the measurement is performed twice for one rotation, the measurement can be performed even if one of the errors occurs. Line L
Since the pulse width is provided, there is no variation in pulse train width. That is, the ends of the pulses are aligned, and a more accurate rotation speed can be obtained. Further, in the case of measuring an accurate linear velocity, the width between the land or groove of the land / groove portion 12 may be narrowed.

FIG. 5 is a plan view showing an arrangement of lands or grooves of the land / groove portion 12. In FIG. 5, the resolution in the radius r direction is defined by the pitches P1, P2, P3 formed in parallel,
It is determined by the beam diameter of the laser light or the like that irradiates P4 and P5. That is, when the beam diameter is sufficiently smaller than the pitch Q, the resolution is improved as the pitch Q is smaller. Therefore, the rotation speed f is equal to the disk 1 for linear velocity measurement.
It is decided by the number of 0 land / grooves (12, 19),
An accurate rotation speed f can be obtained by arranging more. next,
A linear velocity measuring device for measuring a linear velocity will be described with reference to FIGS.

FIG. 6 is a side view showing the structure of an optical disk master device using the linear velocity measuring device of the present invention. In FIG. 6, this linear velocity measuring device has a glass master 31, a turntable 32 on which the glass master 31 is placed, and a pickup 33 arranged at a fixed position. Furthermore, the glass master 3 together with the turntable 32
It has a rotation motor 34 for rotating 1 and a horizontal feed motor 35 and an air slider 36 for moving the glass master 31 in the horizontal direction in order to irradiate the laser light from the pickup 33 in a spiral shape. Further, a linear velocity encoder 39a as the linear velocity measuring disk 10 shown in FIGS. 1, 3 and 4, and a land / groove portion of the linear velocity encoder 39a (land / groove portion 12 in FIG. 1, land in FIG. 4). A linear velocity signal detector 39b that is fixedly arranged while irradiating the groove portions 12 and 19) with laser light and receiving the reflected light, and a rotation speed measurement unit 42 that calculates and measures the rotation speed f. 4 has a radial position measuring unit 43 that calculates and measures the radius r of the land / grooves 12 and 19 in FIG.

Operation in the configuration of this linear velocity measuring device,
The function will be described. The turntable 32 is rotated by the rotation motor 34. That is, the linear velocity encoder 39a is rotated together with the glass master 31. At the same time, lands or grooves formed in the linear velocity encoder 39a (land / groove 12 in FIG. 1, land / groove 1 in FIG. 4).
2, 19) is irradiated with laser light or the like from the linear velocity signal detector 39b and receives reflected light. The reflected light received by the linear velocity signal detection unit 39b is photoelectrically converted and supplied to the rotation speed measurement unit 42 and the radial position measurement unit 43. The radial position measuring unit 43 includes a counter circuit (not shown) and a rotation speed calculating unit, counts the number of pulses n shown in FIG. 2 from the linear velocity signal detecting unit 39b with the counter circuit, and calculates the radius with the calculating unit. Convert to the value of r. The rotation speed measurement unit 42 includes a pulse length conversion circuit, a timer circuit, and a radial position calculation unit.
The pulse train of the pulse number n from the linear velocity signal detection unit 39b is converted into one pulse by the pulse length conversion circuit, the pulse width is measured by the timer circuit, and converted into the rotation speed f shown in FIG. 1 by the calculation unit. .

FIGS. 7 (a) and 7 (b) are waveform diagrams showing a state in which a pulse train of the pulse number n is converted into one pulse by the pulse length conversion circuit. If one pulse shown in FIG. 7B is converted into one pulse width shown in FIG. 7D, FIG.
The entire pulse train with the pulse number n shown in FIG. 7 is formed into one pulse shown in FIG. In this way, the known linear velocity v = r · 2πf described with reference to FIG. 1 is used as the linear velocity not shown from the values of the rotational speed f obtained by the rotational speed measurement unit 42 and the radius r obtained by the radial position measurement unit 43. It is calculated and measured with a measurement circuit.

[0020]

As is apparent from the above description, in the linear velocity measuring method according to the first and second aspects, the radius value of the scanning locus is obtained from the number of pulses included in the pulse train, and the time of the pulse train or the start portion of the pulse train or The number of revolutions of the measured disk is obtained from one rotation time of the measured disk which is between the end points. Furthermore, since the linear velocity of the light-irradiated portion of the measured disk is obtained from the rotational speed and the radius value, the radial position, the rotational speed, and the linear velocity can be measured by a simple method.

In the disk for linear velocity measurement according to claims 3 and 4, in order to obtain the radius value of the scanning locus of at least one rotation, the land, the groove array or the slit penetrating the disk member is located at the center point of the disk member. It is provided in a fan shape in the outward direction. In addition, multiple fan-shaped lands, groove rows, or slit rows are provided without overlapping both ends of the lands, grooves, or slits, so it is possible to measure the radial position, rotation speed, and linear velocity with high accuracy with a simple configuration. Has the effect of becoming.

In the linear velocity measuring device according to the fifth aspect, the radius value of the scanning locus is measured from the number of pulses, and the time of the pulse train or the time of one rotation of the linear velocity measuring disk between the start and end of the pulse train is measured. Since the rotational speed of the measured disk is measured and the linear velocity of the rotating measured disk is calculated from this rotational speed and radius value, the linear velocity can be calculated from the radial position and rotational speed obtained by one detector. There is an effect that the measurement can be performed with high accuracy, the configuration is simplified, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram for explaining an embodiment of a linear velocity measuring method of the present invention.

FIG. 2 is a waveform diagram showing a pulse train signal obtained by the linear velocity measuring method of FIG.

FIG. 3 is a cross-sectional view showing a land or groove in the land / groove portion in FIG. 1 and a state of incidence and reflection of laser light.

4 is a plan view showing a state in which two lands and grooves are formed on the linear velocity measuring disk shown in FIG. 1. FIG.

5 is a plan view showing an arrangement of lands or grooves in lands / grooves of the linear velocity measuring disk shown in FIG. 1. FIG.

FIG. 6 is a side view showing a configuration of an optical disk master device using the linear velocity measuring device of the present invention.

FIG. 7 is a waveform diagram showing a state in which a pulse train of a pulse number is converted into one pulse in the linear velocity measuring device.

FIG. 8 is a side view showing a configuration of a conventional optical disc master exposure apparatus.

[Explanation of symbols]

 10 Disk for linear velocity measurement 12 Land / groove part 14a-14d Land 16a-16c Groove 19 Land / groove part 31 Glass master 32 Turntable 33 Pickup 34 Rotation motor 35 Horizontal feed motor 36 Air slider 39a Linear velocity encoder 39b Linear velocity signal Detection unit 42 Rotation speed measurement unit 43 Radius position measurement unit

Claims (5)

[Claims] 1. Electrically converting reflected light or transmitted light obtained by irradiating light from a fixed position with rotation of a disk to be measured,
Obtaining the radius value of the scanning locus from the number of pulses contained in the pulse train that has been electrically converted, and determining the number of revolutions of the measured disc from the time of the pulse train or one rotation time of the measured disc that is between the start or end of the pulse train. A linear velocity measuring method characterized by. 2. The linear velocity measuring method according to claim 1, wherein the linear velocity of the light-irradiated portion of the measured disk is obtained from the rotation speed and the radius value. 3. A land or groove array parallel to one radius line and having a reflectance different from that of the surrounding disk member or a slit penetrating the disk member is used to determine the radius value of the scanning locus of at least one rotation. A disk for linear velocity measurement, which is provided in a fan shape from the center point of the member toward the outside. 4. The linear velocity measuring disk according to claim 3, wherein a plurality of fan-shaped lands, groove rows, or slit rows are provided so that both ends of the lands, grooves, or slits do not overlap each other. 5. A disk for linear velocity measurement, which is formed in a fan shape from the center point of the disk member in the outward direction and has a land or groove array or slit array arranged parallel to one radial line, and at least the measured object. Rotating means for rotating the linear velocity measuring disc together with the disc, and irradiating the land or groove array or slit array of the linear velocity measuring disc with light and detecting the linear velocity signal for receiving a photoelectrically converted pulse train signal Means, the radius value of the scanning locus is measured from the number of pulses contained in the pulse train when the light from all the lands or grooves or all the slits obtained by the linear velocity signal detection means is electrically converted, and the time of the pulse train Alternatively, a rotation speed / radius value measuring means for measuring the rotation speed of the disk to be measured from one rotation time of the disk for measuring the linear velocity which is between the start portion or the end of the pulse train, A linear velocity measuring device comprising: a linear velocity calculating unit for calculating at least the linear velocity of the disk to be measured rotated by the rotating unit based on the number of rotations and the radius value obtained by the rotating number / radius value measuring unit.