JPS63163151A - Laser power measuring apparatus for disc inspecting equipment - Google Patents

Abstract

PURPOSE:To enable accurate measurement of a laser power emitted, by measuring the radial position of a pickup for disc reproduction to transfer the pickup and a light receiving section facing each other at a fixed distance based on the resulting data. CONSTITUTION:A disc 1 is clamped on a disc clamp table 6 with a clamp arm 3 turning on a shaft 2 and rotated with a main motor 4. The arm 3 has an optical system section 8 extending in the direction of a disc 1 moves radially and a sensor head section 10 connected to a laser power meter 9 is mounted on the arm 3 to measure and display the power of a laser. The optical system section 8 containing a pickup 7 is driven with a feed motor 11 and the position thereof is measured with a position scale 14 to be outputted with a counter 15. An address computing section 26 receives the output to output digital position and a D/A converter 17 applies the data to the motor 11 as analog data 10 control the position of the system section 8.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to a laser power measuring device for a disk inspection device, and in particular to a laser power measurement device for measuring optical information signal q11 (hereinafter referred to as a disk) such as a CD (compact disk). The present invention relates to a laser power measurement device that measures the power of a laser emitted from a pickup of a disk inspection device that inspects physical characteristics and reproduced signal characteristics.

(Conventional technology) In general, during the manufacturing process of discs such as CDs, the shape of pits formed on the disc surface becomes inaccurate, the optical characteristics of MAffi change, or the disc itself is eccentric or deflected (warped). ). Such physical defects on the disc cause playback failures.

For this reason, based on the reproduction signal (PCMffi number) obtained by reproducing various signals recorded as a row of pins on the surface of the disc with a pickup, the physical characteristics of the disc and the reproduction There are various types of disk inspection devices that inspect signal characteristics and determine whether a disk is good or bad. Among these, the present applicant previously proposed a disk inspection device capable of efficiently inspecting the physical characteristics and playback signal characteristics of a disk as described above in a short period of time.
A patent application was filed on September 5, 2009 (Patent application No. 61-2093).
No. 33; title of invention "Disc Inspection Device").

In addition, in the above-mentioned disc inspection equipment, when measuring the power of the laser emitted from the laser diode installed in the pickup for reproducing various signals recorded on the disc, a laser power meter is connected. The laser power was measured by manually arranging the sensor head section (light receiving section) so as to face the objective lens of the pickup of the disk inspection device. For that reason,
It is necessary to align the pickup and the sensor head so that the laser beam emitted from the pickup is accurately incident on the sensor head, and to maintain a constant distance between them.

(Problem to be Solved by the Invention) However, as described above, it is very difficult to manually perform operations when measuring laser power so that the sensor head and pickup are placed in the correct position. There are problems in that it is difficult and the measurement accuracy is insufficient.

In addition, there are also systems in which a special measurement/position for laser power measurement is provided within the disk inspection device, and the pickup's laser power is measured at that measurement position when measuring the laser power. , this is a transport mechanism (feed) that allows the pickup to be moved outside of the range where the pickup is moved for normal disc playback.
There is a problem in that this requires a movable range, which requires extra space within the disk inspection device.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the conventional technology, and provides accurate positioning for measuring the power of the laser emitted from the pickup within the range in which the pickup is moved for normal disc playback. It is an object of the present invention to provide a laser power measurement device for a disk inspection device that can be easily performed.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention converts various signals recorded as a row of pits on the surface of a disk into playback signals obtained by playing back with a playback pickup. A laser power measurement device for a disk inspection device that measures the power of a laser emitted from the pickup in a disk inspection mounting that inspects the physical characteristics and reproduction signal characteristics of the disk based on the disk, the pickup being mounted in the radial direction of the disk. a position scale for measuring the radial position of the pickup; and a position scale for measuring the radial position of the pickup. A light-receiving section is installed to face the pickup within a range of 1 and 2, and receives the laser emitted from the pickup, and the pickup is located at a certain distance from the light-receiving section based on the pickup position data measured by the position scale. A laser power measuring device for a disk inspection apparatus is provided, which includes a transfer control means for controlling the transfer operation of the transfer means so as to face each other, and a laser power measuring section for measuring the power of the laser beam received by the light receiving section. be.

(Function) In the laser power measurement device of the disk inspection device configured as described above, the radial position of the pickup is measured,
Based on the measured pickup position data, the pickup is moved to face the light receiving section at a constant distance. and,
The laser power measuring section measures the power of the laser beam received by the light receiving section.

(Embodiment) An embodiment of the laser power measuring device for disk inspection HE according to the present invention will be described below with reference to the drawings.

FIG. 1 is a block system diagram showing an embodiment of a laser power measuring device for a disk inspection device according to the present invention.

In the figure, disk 1 has i! loaded on a loading table (not shown). The disc is taken into the disc inspection device in this state. This disc inspection 5A is based on the reproduction signal (PCM signal) obtained by reproducing various signals recorded as a row of pits on the surface of the disc with a pickup as described above. This test determines whether a disc is good or bad by inspecting its physical characteristics and playback signal characteristics. The disk 1 is then clamped onto a disk clamp table 6 attached to the tip of the shaft 5 of the main motor 4 by applying a pressing force to the disk 1 by a clamp arm 3 rotating in the direction of the arrow about the shaft 2.

The clamp arm 3 has an optical system section 8 including a big aperture 7.
extends in the direction of movement in the radial direction of disk 1,
Furthermore, this clamp arm 3 has a state 8 (without the disk 1) (
In other words, disc 1 is not taken into the disc inspection device! 21) and when it is down to the clamp position, it is arranged horizontally, that is, parallel to the moving direction of the pickup (state f!3 of the solid line position shown in the figure).

Further, as shown in the figure, a sensor head section (light receiving section) 10 connected to a laser power meter 9 is attached to a part of the clamp arm 3.

The laser power meter 9 measures the power (light intensity) of the laser received by the sensor head section 10 and displays it as digital data.

Further, the optical system section 8 including the pickup 7 is driven by a feed motor 11 and is moved in the radial direction of the disk 1 by a transport mechanism constituted by a rack 12 and a pinion 13. Furthermore, this pickup 7
A position scale (linear scale) 14 is attached to measure the position in the radial direction.

This position scale 14 transmits the movement (position) of the optical system section 7, and is composed of a light emitting section, a light receiving section, and a slit (all not shown), and the pulse train is converted into position data with a position accuracy of 2 μm. is output as Furthermore, an origin signal detection section is incorporated to know the initial position.
When the pickup 7 passes through a portion near the innermost circumference of the disk 1, position data of the pickup 7 at this time is output as an origin pulse. Then, by supplying this origin pulse to the counter 15, the counter 15 is cleared (reset), and furthermore, by supplying a pulse train to the counter 15 according to the position of the pickup 7, the origin position of the pickup 7 is The relative position of .

The output count data of this counter 15 is stored in a ROM (Rea).
The address data is supplied as address data to the address calculation section 1G, which is configured by the d0nly Memory).

Data (position data) corresponding to output argument data (this becomes address data) from the counter 15 is stored in advance in the ROM constituting the address calculation section 16. Then, this address calculation unit 1G outputs data (position data) in the ROM corresponding to the supplied address data, which is converted from digital data to analog data by a D/A (digital/analog) converter 17. , furthermore, the feed motor 11 is connected via the changeover switch 18.
is supplied as a driving voltage (control voltage).

The changeover switch 18 is configured to switch between the control voltage for driving the feed motor 11 supplied from the V1111 voltage generator 19 during normal playback when the pickup 7 is normally transferred in a normal disk playback state, and the D/A converter 17 during laser power measurement. Control iIl for driving the feed motor 11 supplied from
It is used to switch the voltage.

FIG. 2 is a diagram showing the relationship between the position of the pickup 7 in the disk radial direction and the control pressure supplied to the feed motor 11.

As shown in the figure, a sensor head 1 of a laser power meter 9 for measuring the laser power of a pickup 7 is shown.
Assuming that the position 0 is at the radius r = 271I11 of the disk 1, if the pickup 7 is located on the inner circumferential side (r<27em), the optical system section 8 including the pickup 7 is moved toward the outer circumference. A positive (+) fIl that causes
l l ffi pressure is output, and on the other hand, the outer peripheral side (
r > 27mm), if the pickup 7 is located at
A negative (-) control voltage that moves the optical system section 8 including the pickup 7 in the inner circumferential direction is output.

Incidentally, since hunting occurs if there is a change in the polarity of the control voltage in the vicinity of the radius r=27ff1m, a dead zone region of, for example, ±50 μm is provided to the extent that this does not cause an error in laser power measurement.

Furthermore, in order to compensate for the position difference when mounting the sensor head section 10 of the laser power meter 9, the address calculation section (R
Preset address data to be added to or subtracted from the preleft address generation section 20 is supplied to the address data supplied to OM>16, so that the address can be increased or decreased.

In the laser power measurement device of the disk inspection device configured as described above, when the laser power measurement mode switch (not shown) provided in the disk inspection device is turned on to enter the laser power measurement mode, a state in which there is no disk (that is, a disk 1 is not taken into the disk inspection device), the clamp arm 3 becomes horizontal, and the pickup 7
The laser diode (f, not shown) installed in lights up,
A laser beam is emitted.

At the same time, the changeover switch 18 is switched to the side shown in FIG. tll voltage and feed motor 1 according to this control voltage.
1 is driven, and the pickup 7 is automatically transferred to a predetermined position by a transfer mechanism constituted by a rack 12 and a pinion 13. Furthermore, the laser power (light intensity) received by the sensor head unit 10 connected to the laser power meter 9 is displayed and measured as digital data by the laser power meter 9, and the laser power required for inspecting the disk is measured. An inspection will be carried out.

As described above, in the embodiment of the present invention, the laser power meter 9
The sensor head section 10 is attached to the clamp arm 3, which is arranged horizontally, that is, parallel to the moving direction of the pickup 7, without the disk 1, and the positioning of the disk 1 in the radial direction is performed using a position scale ( The position data from the linear scale) 14 is transferred to the address calculation unit 16. This is done by controlling the drive of the feed motor 11 using the control 11 voltage converted by the D/A converter 17.

Therefore, by placing the sensor head 10 of the Rade power meter 9 on the clamp arm 3, the output power of the laser emitted from the laser diode provided in the pickup 7 through the reading lens can be adjusted with good directivity. Measurements can now be taken at a constant distance and under the same conditions.

In addition, the position scale (linear scale) 14 is used to measure the radial position of the disk 1 at highly accurate intervals of about 2 μn1, and the count group (il number data) from the origin position of the position scale 14 is also addressed. By converting the data in the ROM constituting the arithmetic unit 1G and by providing a dead zone area that does not cause any inconvenience in measuring the laser power, the feed motor 11 can prevent the pickup 7 from hunting and can quickly achieve the desired value. You will be able to move it to the correct position.

Furthermore, there are no additional components unnecessary for normal disk playback, and no extra space is required to measure the laser power emitted from the pickup.

In addition, in the above-mentioned embodiment, it was explained that the power of the laser emitted from the laser diode provided in the pickup 7 is measured, but the power of the laser emitted from not only this laser diode but also other laser elements or laser tubes can be measured. Of course, it can also be applied to the measurement of laser power.

(Effects of the Invention) As described above, according to the laser power measuring device of the disc inspection device according to the present invention, the power of the laser emitted from the pickup can be measured within the range in which the pickup is moved for normal disc playback. It has the advantage that positioning can be performed accurately and easily, and additional space is not required for measuring the laser power emitted from the pickup.

[Brief explanation of the drawing]

FIG. 1 is a block system diagram showing an embodiment of the laser power measuring device of the disk inspection device according to the present invention, and FIG. 2 shows the relationship between the position of the pickup 7 in the disk radial direction and the control voltage supplied to the feed motor 11. It is a figure showing a relationship. 1... Disc, 2... Axis, 3... Clamp arm, 4... Main motor, 5... Shaft, 6...
・Disc clamp table, 7...Pickup, 8...Optical system section, 9...Laser power meter, 10...Sensor head section, 11.
...Feed motor, 12...Rack, 13...Binion, 14...Position scale, 15...Counter, 16...Address calculation section, 17...D/A
Converter, 18... Selector switch, 19... υ1011 voltage generator during normal playback, 20...
・Preset address generation section.

Claims (2)

[Claims] (1) In a disk inspection device that inspects the physical characteristics and playback signal characteristics of a disk based on the playback signal obtained by playing back various signals recorded as a row of pits on the surface of the disk with a playback pickup. A laser power measuring device for a disk inspection device that measures the power of a laser emitted from the pickup, the device comprising: a transfer means for transferring the pickup in the radial direction of the disk; a position scale for measuring the radial position of the pickup; , installed to face the pickup within the movable range of the pickup for normal disc playback,
and a light receiving section that receives the laser emitted from the pickup, and a transfer control that controls the transfer operation of the transfer means so that the pickup faces the light receiving section at a constant distance based on the pickup position data measured by the position scale. A laser power measuring device for a disk inspection apparatus, comprising: means; and a laser power measuring section that measures the power of a laser beam received by the light receiving section. (2) The light receiving section is attached to a clamp arm that clamps the disc in a normal disc playback state and is arranged parallel to the moving direction of the pickup when there is no disc. A laser power measuring device for a disk inspection device according to item 1.