JPH02118931A - Optical disk stamper inspection instrument - Google Patents

Abstract

PURPOSE:To prevent the deterioration in a reproduced signal by directing a face of an optical disk stamper with no signal recorded thereupon downward and using a magnet chuck mechanism so as to attract a face with no signal recorded thereon. CONSTITUTION:A magnet chuck main body 13 attracting an optical stamper 16 being an object of check and correcting a face deflection is supported by a housing 14 with bearings 13a, b and driven by a spindle motor 11 via a coupling 12. A coil 17 is incorporated in the inside of the chuck main body 15 and a current is supplied by a feed means comprising a brush 27 and a spring 28 from a power supply 20. The surface of the chuck main body 15 is partitioned by a partition plate 18 made of a nonmagnetic material and an adsorbing plate 19 made of a magnetic material is fitted to the surface to form an electromagnet. A magnetic line of force 26 generated from the coil 17 passes through the stamper 16 to allow the adsorbing plate 19 adsorb a face 16a of the stamper 16 with no signal recorded thereupon, and when the stamper is removed, a switch 21 is turned off to interrupt the current to the coil 17.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an optical disk stamper inspection device 1.

[Prior Art] Conventionally, as shown in FIG. 6, the surface of an optical disk stamper 63 to be inspected is irradiated with laser light that is focused into a minute or pot, and the reflected light from the surface of the optical disk stamper 63 is detected. As a device for inspecting surface defects etc., a chuck mechanism 62 such as a magnetic chuck is used to chuck only the vicinity of the center hole of the optical disc stamper 63, and the surface 6 where the signal of the optical disc stamper 63 is recorded.
By chucking 3b facing downward, dust and dirt are prevented from adhering to the surface 63 of the optical disk stamper, and the amount of reflected light that has changed due to the influence of lumps and dirt is removed from defects on the surface of the optical disk stamper 63. An optical disk stamper inspection device is known that prevents erroneous judgments.

[Problems to be Solved by the Invention] In such a conventional optical disk stamper inspection device, the thickness of the optical disk stamper to be inspected is approximately 30 mm.
The optical disc stamper is as thin as 0 microns, and the stress generated during the plating process during the manufacturing process of the optical disc stamper is released during the subsequent peeling process, which increases the surface runout. The amount of deviation increases, causing deterioration of the detection signal. Therefore, a degraded detection signal may be erroneously determined to be a defect on the surface of the optical disk stamper.

Therefore, the present invention is intended to solve one such problem.The purpose of the present invention is to prevent dust, chips, etc. from adhering to the surface of the optical disk stamper, and to correct the surface wobbling of the optical disk stamper. An object of the present invention is to provide an optical disk stamper inspection device that can accurately inspect defects on the surface of an optical disk stamper without erroneously determining them by reducing the defocus of the spot and preventing deterioration of the reproduced signal.

[Means for Solving the Problems 1] The optical disk stamper inspection device of the present invention irradiates the surface of an optical disk stamper to be inspected with a laser beam focused on a minute spot, and measures the amount of light reflected from the surface of the optical disk stamper (by By doing this, in the optical disk stamper inspection device that inspects defects etc. on the surface of the optical disk stamper, the side of the optical disk stamper where the signal is recorded is facing down, and the side where the signal is not recorded is placed using the magnetic chuck gutter groove. It is characterized by adsorption.

(Function 1) According to the optical disk stamper inspection apparatus of the present invention, the surface of the optical disk stamper to be inspected on which the signal is recorded faces downward to prevent dust, clumps, etc. from adhering to the surface. By using a magnetic chuck mechanism to attract the surface of the optical disk stamper on which no signal is recorded, the surface of the optical disk stamper is corrected, the optical disk focus shift is reduced, and the deterioration of the reproduced signal is prevented. It becomes possible to accurately inspect defects without erroneously determining them.

[Actual journey example 1] Hereinafter, the present invention will be explained in detail based on the drawings.

FIG. 1 is a schematic diagram of an example of the configuration of an optical disk stamper inspection apparatus according to the present invention. In FIG. 1, the main chuck body 15 that attracts the optical disc stamper 16 to be inspected and corrects the runout in one plane includes bearings 13a and b.
is supported by a housing 14 and rotated by a spindle motor 11 via a coupling 12.

A coil 17 is incorporated inside the chuck body 15, and a brush 27 and a sling ring 28 are connected to the power source 20.
Current is supplied by a power supply means such as. The surface of the chuck body 15 is treated as a partition 18 made of non-6R1 raw material.
A suction plate I9 made of linic material is attached to form a block. Generated from coil 17 1
-6n line of force 26 passing through the standber 16, the suction plate 19 attracts the surface 16a of the standber 16 on which no signal is recorded. On the other hand, when removing materials, such as at the end of an inspection, the switch 21 is turned off to cut off the supply of current to the coil 17 (thereby, the standby bar is removed).

Although FIG. 1 shows an example in which a brush and a slip ring are used as means for feeding power to the coil, a water root contact or the like may also be used instead.

Surface 16 on which signals of optical disk stamper 16 are recorded
1) faces downward and faces the optical pickup 23 when it is attracted to the magnetic chuck. On the other hand, the optical pickup 23 attached to the head feeder 22 is
The surface of an optical disk stamper 16 rotated by a spindle motor 11 is irradiated with a laser beam focused on a microscopic pot, and the reflected light from the surface of the optical disk stamper 16 is detected to obtain a reproduction signal 24. Obtained playback signal 2
4 is sent to a signal processing circuit 25 for defect inspection, and the surface of the optical disk stamper 16 is inspected for defects.

An example of a magnetic chuck is one using an electric stone, as shown in FIG. An example of this is shown in Figure 2. FIG. 2(a) is a sectional view of the magnetic chuck when the stand bar is being attracted, and FIG. 2(b) is a sectional view of the magnetic chuck when the stand bar is removed. In this example, a permanent 6n stone 32 partitioned by a pole iron plate 31 is used as a source of oral force. Chuck body 1
The surface of 5 is partitioned by a partition plate 30 made of a non-Iin material 4, and a suction plate 29 made of a metal material is attached, as in the first configuration example.

When adsorbing the stand bar, the permanent a+ stone 32 is attached to the partition plate 3.
0, and as shown in FIG.

On the other hand, when removing material, the permanent mstone 32 is moved above the suction plate 29 by a driving means (not shown) such as a cam, so that the 5f1 force line 26 is changed as shown in FIG. 2(b). You will pass through the inside of Nijyak.

In all of these magnetic chucks, the surface runout of the suction plate 29 is finished to be less than 50 microns, which is the standard value for compact disc surface runout, and the surface runout can be corrected by adsorbing the optical disc stamper 1G. is possible.

Figure 3 shows compact discs (CDs), CD-ROMs,
FIG. 2 is a block diagram showing an example of the configuration of the signal processing circuit 25 for a CD-I or other read-only optical disk stamper inspection device. Reproduction signal 2 detected by optical pickup 23
4 is decoded into a scaled format signal by the decoder 33 and then input to the error detection and correction circuit 34. If there is a defect on the surface of the optical disk stamper, the laser beam irradiated from the optical pickup 23 is disrupted and the amount of reflected light decreases, resulting in a small reproduction signal amplitude. The error detection and correction circuit 34 detects code errors at locations where the reproduced signal amplitude becomes small. Therefore, defects on the surface of the optical disk stamper can be detected by observing the code error state. Next, a counting circuit 3 calculates the code errors caused by the detected defects.
5, and the recording circuit 36 records the location and size of the defect.The stored data is processed by a personal computer (not shown).

FIG. 4 is a block diagram showing an example of the configuration of the signal processing circuit 25 for a write-once or rewritable optical disc stamper inspection device in which a signal recording guide groove is pre-recorded, and FIG. It is a signal output diagram of various places in the figure. The reproduced signal 24 shown by the solid line in FIG. 5(a) is
When there is no defect on the surface of the optical disk stamper, the signal amplitude is 51a, but when the laser beam from the optical pickup is disrupted by the defect, the signal amplitude becomes small as 52a. The comparator 41 detects defects by comparing the reproduced signal 24 with a reference value, and outputs an output signal 42 as shown in FIG. 5(b) to a counting circuit 43 and a memory circuit 44.

If the optical disk stamper has a large surface runout and the optical spot is out of focus, or if there is dust or debris on the surface of the optical disk stamper, the reproduced signal amplitude will change as shown at 53a in FIG. 5(a). However, in the optical disk stamper inspection apparatus of the present invention, the surface of the optical disk stamper (here, the bumps are slightly thicker, and the surface wobbling of the optical disk stamper is corrected). Therefore, erroneous determination of defects can be prevented.

Although FIG. 1 shows tR'U in which the feed 1 lateral 22 is used for moving the optical pickup 23, this structure may also be used for moving the chuck 1 lateral 11.

(Effect of the Invention 1 As described above, according to the present invention, since the chuck structure of the optical disk stamper is such that the side on which the signal is recorded faces downward, dust, clumps, etc. will not adhere to the surface of the optical disk stamper. Furthermore, since the surface contact of the optical disk stamper is corrected and the defocus of the optical spot is reduced to prevent deterioration of the reproduced signal, it is possible to accurately inspect the surface of the optical disk stamper without erroneously determining defects.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of a first embodiment of the optical disc stamper inspection device of the present invention, FIG. 2 is a sectional view of the second embodiment, and FIG. 3 is a signal processing circuit of a read-only optical disc stamper test device. FIG. 4 is a block diagram showing an example of a signal processing circuit for a write-once type or rewritable optical disk stamper inspection device, and FIG.
FIG. 6 is a schematic diagram of a conventional optical disk stamper inspection device. l 5 ・ 16 ・ 23 ・ 25 ・ ・Chuck body, optical disk stamper, optical big amplifier, signal processing circuit and above Applicant Seiko Epson Co., Ltd. Agent Patent attorney Kizobe Suzuki (and 1 other person) Figure 2 (a)
) 7th 30th Honey Figure 4 (Q) (b')

Claims (1)

[Claims] In an optical disk stamper inspection apparatus that inspects defects, etc. on the surface of the optical disk stamper by irradiating the surface of the optical disk stamper to be inspected with a laser beam focused on a minute spot and detecting the amount of reflected light from the surface of the optical disk stamper, An optical disk stamper inspection apparatus characterized in that the surface of the optical disk stamper on which signals are recorded faces down, and the surface on which no signals are recorded is attracted using a magnetic chuck mechanism.