JPS6070541A - Testing device of information disc - Google Patents

Abstract

PURPOSE:To increase a testing area per unit time and to make it possible to test also a fine defect for a short time by scanning an optical beam in the circumference direction of a disc and also in the radius direction. CONSTITUTION:An optical beam reflected by the disc 38 is passed through a mirror 36 and a lambda/4 plate 35, reflected by a beam splitter 34 and inputted to a defect detecting circuit 40 through a photodetector 39 to detect a defect. An ultrasonic light deflector 32 diffracts a laser beam, an optical spot on the disc 38 is oscillated in the radius direction by changing the angle of diffraction and the disc 38 is rotated by the diameter of the optical spot every period of the vibration, so that the disc surface can be tested in the circumference direction closely. If the disc 38 is moved in the radius direction by the oscillated distance of the optical spot during one rotation of the disc 38, the radius direction of the disc 38 can be also tested without leaving an untested part.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to 1,110 leprosy yen (・Saeken jF<if'!).

[Technical background of the invention and its problems]

In recent years, information has been stored on disks such as video disks, digital audio disks, and hard disks for electronic computers.
As described in Section 6, many devices have been devised that contribute to this. In these high-density IL recording disks, minute defects of about 2 to 3 microns on the recording surface have a large effect on the recording and reproducing performance (1 disk production). The management is f,4' on baking soda.

Conventionally, the inspection disk inspection device d irradiates a laser beam onto the inspection disk and detects defects from changes in the reflected light. No. 11 is a diagram showing a conventional example of the configuration of a housing for an information disk inspection device. A light beam emitted from a laser 11 passes through a beam splitter 12 and a λ/4 plate 13, is reflected by a mirror 14, and is focused on a small original spot on a disk 16 by a converging lens 15. The original beam reflected by the disk 16 passes through the mirror 141 and the λ/4 plate 13, is reflected by the beam splitter 2, and enters the photodetector 17. The output of the original detection circuit is input to the defect detection circuit 18, and defects are detected. Disc 1
6 is rotated by a motor 19 and moves in the radial direction, so the light spot spirals around the disk. Fig. 2 is a diagram showing how the light spot scans the disk.

Generally, the ability to detect defects is improved by reducing the diameter of the light spot irradiated by the disk.

However, if the original spot is made smaller in order to detect the Imaki Elementary School 4C defect, the radial movement speed of the disk must be made smaller in order to inspect the entire surface (with a circle), and as a result, the inspection time is reduced. (There was a drawback.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to provide an information circle inspection system which improves the drawbacks of the conventional apparatus and is capable of inspecting even minute defects in a short period of time.

[Summary of the invention]

In this invention, the light beam is scanned not only in the circumferential direction of the disc but also in the radial direction, thereby increasing the inspection area per part time and shortening the inspection time.

[Disadvantage of the Invention] According to this invention, even minute defects on an information disk can be inspected in a short time.

[Actual cannon 1fQ of the invention] The -X bKQ 1"!l of this invention will be explained and explained in detail with reference to the drawings. Figure 3 of the book is a diagram showing the +11\ composition of this θ invention. Laser 31 The original beam emitted from the ultrasonic optical deflector 32. slit 33. beam splinter 3
A 4° λ/4 plate 3-plate table 5 is bent by a passing mirror 36, and a convergent lens 37 connects a micron fC spot of approximately 7 mm on a disk 38. Here IIZ East lens 37
is equipped with a self-dI focusing mechanism. The light beam reflected by the disk 38 is reflected by the mirror 36. The light passes through the λ/4 plate 3 plate stand 5, is reflected by the beam splitter 34, and enters the photodetector 39.The output of the photodetector is input to a defect detection circuit 40, and a defect is detected. The ultrasonic light fM deflector 32 diffracts the laser beam and changes the angle of diffraction to move the light on the disk 38 in the radial direction. Only the diffracted light that is output from the detector 32 (11r) and 20) and is used for the first and third measurements is allowed to pass through.

The disk 36 is rotated by a motor 41 and moves in the radial direction. Figures 8 to 4 show how the light spot scans the disk, with 1≧1.

The light spot 45 is the ultrasonic light 11. The disk rotates in the radial direction by the ii direction device, but at the same time, the disk rotates by the diameter of the light spot during the vibration θ lunar circumference j!'JJ, and the circumference The solar eclipse moves in the radial direction along with minute vibrations of the light spot, but if the disk is moved by the vibration distance of the spot during one rotation of the disk, the eclipse can be inspected without gaps. For example, when the maximum inspection radius of a disk is 2° C11l, the vibration pressure in the radial direction of a light spot of 10 μm and the width of 10 μm
, the frequency of the light spot 630KB, z, the rotation speed of the disk]
If it is OHz, the moving speed of the disk is qf 1 mm/se
C can be used throughout (・Q can be used.

However, the original spot should not be vibrated in the radial direction.
This is the movement of 1 yen σ・Ka speed・・I″I); Q, ] m
m/'sec. Therefore, in the example, the inspection time is reduced by about 1/1o by the present invention.47. Ru.

[110 Examples of Inventions] Although an ultrasonic deflector was used as the optical deflector in the first example, an optical deflector using an electro-optic effect can also be used.

[Brief explanation of the drawing]

Fig. 1 is a +10 diagram of a conventional example from the Information Disc Inspection Equipment Agency, Fig. 2 is a diagram showing the state of a light spot scanning on a disc in the conventional example, Fig. 3 is a configuration diagram of the present invention, and Fig. 4 The figure is a diagram showing a state of a light spot scanning a disk according to the present invention. 11... Laser, 12... Beam splitter, 13...
...λ/4 plate, 14... Mirror, J5... Focusing lens, 16... Inspection disk, 18... Defect detection circuit, 1
9... Disc rotating motor, 21... Light spot 31... Laser, 32... Ultrasonic optical deflector, 33...
...Slit, 34...Beam splitter, 35...
・λ/4 plate, 36... Mirror, 37... Focusing lens, 38... Inspection disk, 39... Photodetector, 40...
・Defect detection circuit, 41... Disk rotation motor, 45...
・Light spot.

Claims (1)

[Claims] A light beam is focused on the rotating information disk, and the information disk is moved in the radial direction of the information disk relative to the light beam to scan the information disk, and the resulting reflected beam is used to detect the information disk. i6 degree information 4f to detect defects
1a-Serpent disk side L