KR100902893B1 - Apparatus and method for mechanical test of optical disk surface - Google Patents

Abstract

The present invention is to provide an optimum evaluation apparatus and method for quantifying the mechanical durability characteristics to improve the mechanical properties of the optical disk surface, the rotating plate for placing the optical disk and rotating the optical disk through a rotational movement, and the rotating plate And a scratch portion formed in a position perpendicular to the optical disk and contacting the optical disk to generate a scratch on the surface of the optical disk through a linear motion, and holding the scratch portion and applying a predetermined pressure through a vertical motion with the surface of the optical disk. It is configured to include a frame applied to the contact surface between the portion and the optical disk.

Durability rating, optical disc, steel wool, protective film

Description

Apparatus and method for mechanical test of optical disk surface

1 is a view showing an apparatus for testing the mechanical durability of the optical disk surface according to the present invention

2 is a flow chart showing a mechanical durability inspection method of the surface of the optical disk according to the present invention.

Figure 3 is a graph showing the jitter evaluation results after the scratch test according to the pressure and the number of revolutions of the disc applied to the optical disk according to the present invention

FIG. 4 is a view in which a predetermined scratch pattern is formed on an optical disc using a microscratch tester according to the present invention. FIG.

5 is a view showing the scratch depth generated according to the pressure applied to the optical disk according to the present invention through an experimental value;

Figure 6 is a graph showing the scratch depth with pressure to quantify the mechanical durability test method of the surface of the optical disk according to the present invention

* Explanation of symbols for main parts of the drawings

10: rotating plate 20: optical disk

30: scratch part 31: steel wool                 

40: frame 50: motor

The present invention relates to quality inspection of optical discs, and more particularly, to an apparatus and method for inspecting the mechanical durability of an optical disc surface.

Until now, the recording medium includes a magnetic recording tape, an LD (Laser Disc) or CD (Compact Disc) as an optical disc, and a DVD (Digital Video Disc), which has been recently produced with a large capacity for storing information.

Among these recording media, optical discs use digital recording methods different from the conventional magnetic recording tapes, and because they have very small volume and weight, they are very efficient for storage and movement. Is very high.

However, in any product, the manufactured product should be able to be used without any defects, and if problems with the quality of the product occur, it will reduce the trust of the producer who produced the product.

The same holds true for optical discs. In particular, optical discs having very fine signal characteristics have resulted in poor quality due to scratches, mold defects, fingerprints, and adhesion of foreign matters during the manufacturing process.

As a result, the completed optical disc is subjected to quality inspection as a next step, which is then shipped to the optical disc market.

Quality inspection of conventional optical discs is generally carried out by four measuring drives.

First, on the assumption that the characteristics of the optical discs manufactured from the same device are the same, the producer selects an arbitrary optical disc from all the optical discs manufactured and mounts it in the measurement system.

In the first measurement drive, high frequency signals and jitter are measured by signals reproduced from the optical disc.

The second measurement drive measures servo signals (focusing error signal and tracking error signal) based on the signal reproduced from the optical disc.

The third measuring drive measures the mechanical properties of the optical disc under quality inspection.

And the last fourth measurement drive measures the optical characteristics of the optical disc.

As described above, the conventional optical disc quality inspection checks the accuracy of information recording, the mechanical characteristics and optical characteristics of the optical disc.

Of these, mechanical damage, that is, scratches, that may occur on the incident surface of the information recording / reproducing laser beam during the use of a high density optical disc, is not only a signal deterioration of the optical disc, but also a loss of data and, in severe cases, recording or reproducing information on the disc. Even the situation that is not possible can occur, which is the largest part of the optical disc quality inspection.

Therefore, in order to prevent this, a protective coating may be formed on the surface of the disk to improve mechanical strength or hardness.

However, for this purpose, after forming a protective film on the surface of the disk, the mechanical properties of the protective film must be quantified. In other words, it is necessary to quantify how much to withstand scratches that may occur during use of the disc.

Among these, as an evaluation method for quantifying scratches on the surface of a high density optical disk, a pencil hardness test method and a taper abrasion test method are used.

The pencil hardness test is a method in which pencils having different strengths are contacted with a disk through a linear motion to evaluate the hardness value corresponding to the pencil hardness at the time of scratching.

In addition, the taper polishing test is a kind of polishing wheel, which is a method of judging by the degree of endurance by uniformly abrading the surface while applying a predetermined load by the D1004 method of ASTM (American Society for Testing and Materials) standard, which is an American standard inspection standard. to be.

However, the tape polishing test is a method of judging the surface of a disk by abrasion and the like, unlike scratches generated during use, which means that the actual scratches are used to drive the disk (for example, an optical disk drive). There is a problem that can not be properly quantified because it shows a large difference from the situation in which the reaction in the).

In addition, the pencil hardness test is a method in which a person contacts the surface of a disc through a pencil to generate scratches, and it is difficult to continuously maintain the same pressure, and the number of scratches does not occur as much as desired. There is no problem.

In addition, the pencil hardness test method and the taper abrasion test method represent a criterion for evaluating the degree of scratch occurrence between a protective film formed on an optical disk and a non-formed one. It is not possible to quantify the degree of defect based on the value set.

Therefore, even if classified as defective or good through the above inspection, this is a classification by the relative evaluation of the manufacturer with a long know-how, not a quantified classification according to the realistic absolute reference value, so many errors.

 As described above, there is no particular method for quantifying the degree of occurrence of scratches for inspecting the mechanical durability of the surface of the optical disc while having a great influence on the quality of the optical disc. Therefore, it is urgent to develop a quantification method for this.

Accordingly, an object of the present invention is to provide an optimum evaluation apparatus and method for quantifying the mechanical durability characteristics in order to improve the mechanical characteristics of the optical disk surface.

Another object of the present invention is to provide an apparatus and method for testing the mechanical durability of an optical disk surface, which can reduce inspection cost while increasing reliability.

It is still another object of the present invention to provide an apparatus and method for quickly and accurately classifying a defective or good product by setting a realistic absolute reference value.

Another object of the present invention is to increase the reliability of the mechanical durability inspection of the surface of the optical disk by causing the scratches closest to the scratches that can occur in real life.

Features of the mechanical durability inspection device of the surface of the optical disk according to the present invention for achieving the above object is a rotating plate for rotating the optical disk through the rotational movement and the optical disk, and formed in a position perpendicular to the rotating plate and on the optical disk A scratch portion which contacts and generates a scratch on the surface of the optical disc through a linear motion, and a frame which holds the scratch portion and applies a predetermined pressure to the contact surface of the scratch portion and the optical disc through vertical movement with the surface of the optical disc. It is composed.

In this case, the scratch unit is preferably composed of a holding area holding the frame and a scratch area in contact with the optical disk.

The scratch area is made of steel wool, and the type is preferably made of any one of # 0, # 00, # 000, and # 0000.

In addition, the rotating plate is preferably configured to further include a rotary motor at the bottom.                     

In addition, the predetermined pressure through the frame is preferably set to a pressure of 5000gf / ㎠ or less at 50gf / ㎠ or more, preferably at a pressure of 1500gf / ㎠ or less at 500gf / ㎠ or more.

Features of the method for testing the mechanical durability of the surface of the optical disk according to the present invention for achieving the above object is the step of fixing the optical disk on the rotating plate, rotating the optical disk with the rotating plate, and in the vertical direction from the top of the rotating optical disk Contacting the optical disc with the scratch portion by applying a predetermined pressure defined in accordance with the scratch test through a frame positioned at the top of the scratch portion in a direction perpendicular to the optical disc by moving the scratch portion with the frame. Increasing the pressure, maintaining the contact pressure of the optical disc and the scratch unit by the rotational speed of the predetermined optical disc, and then separating the scratch unit in contact with the optical disc through the vertical movement of the scratch unit; Times And separating the defects from the front plate and inspecting durability through scratches generated on the surface of the optical disc, to distinguish between defective and good quality.

At this time, it is preferable to further comprise the step of positioning the other optical disk to be inspected on the rotating plate to repeat the operation to distinguish between good and bad.

The predetermined pressure defined according to the scratch test is preferably set to a pressure of 5000 gf / cm 2 or less at 50 gf / cm 2 or more, and preferably to a pressure of 1500 gf / cm 2 or less at 500 gf / cm 2 or more.                     

In addition, the step of distinguishing the defective and good quality is when the depth of scratches generated on the surface of the optical disk is less than 2㎛ than 0㎛, if the depth of scratches generated on the surface of the optical disk is 2㎛ or more It is desirable to classify as defective.

In addition, the preset rotation speed of the optical disc is preferably 5 rotations or less.

Other objects, features and advantages of the present invention will become apparent from the following detailed description of embodiments taken in conjunction with the accompanying drawings.

A preferred embodiment of the apparatus and method for testing the mechanical durability of an optical disk surface according to the present invention will be described with reference to the accompanying drawings.

1 is a view showing a mechanical durability inspection apparatus of the surface of the optical disk according to the present invention.

As shown in FIG. 1, the rotating plate 10 which rotates the optical disc 20 by placing the optical disc 20 thereon, and is formed at a position perpendicular to the rotating plate 10, is in contact with the optical disc 20. The scratch unit 30 which generates a scratch on the surface of the optical disk 20 through a linear / reciprocating motion, and the predetermined pressure through a vertical movement with the surface of the optical disk 20 while holding the scratch unit 30. It is composed of a frame 40 to apply to the contact surface of the scratch unit 30 and the optical disk 20.

At this time, the predetermined pressure through the frame 40 is 50 ~ 5000 gf / ㎠, which is a load condition that the scratch depth causes a depth of 2 ㎛ is preferably 500 ~ 1500 gf / ㎠.                     

The scratch unit 30 is divided into a holding area holding the frame 40 and a scratch area 31 in contact with the optical disk, and the scratch area 31 is formed of steel wool. desirable.

At this time, the steel wool is preferably composed of any one of the types of # 0, # 00, # 000, # 0000.

In addition, the rotary plate 10 constitutes a rotary motor 50 at a lower end thereof, such that the rotary plate 10 is rotated by the driving of the motor 50.

Referring to the accompanying drawings, the mechanical durability inspection method of the optical disk surface according to the present invention configured as described in detail as follows.

2 is a flowchart illustrating a mechanical durability inspection method of an optical disk surface according to the present invention.

As shown in FIG. 2, first, the optical disk 20 is fixed on the rotating plate 10, and then the motor 50 located at the bottom of the rotating plate 10 is driven to rotate the optical disc 20 together with the rotating plate 10. (S10).

Subsequently, the scratch unit 30 is moved in the vertical / return direction at the upper end of the rotating optical disc 20 to contact the lower end of the scratch unit 30 with the optical disc 20 (S20).

The predetermined pressure defined according to the scratch test is applied to the optical disk 20 in the vertical direction through the frame 40 positioned on the scratch part 30 to increase the contact pressure between the optical disk 20 and the scratch part 30. Increase (S30).                     

At this time, the pressure to be applied at the time of the scratch inspection is 50 to 5000 gf / ㎠, preferably 500 to 1500 gf / ㎠.

3 is a graph showing the jitter evaluation result after the scratch test according to the pressure and the number of rotation of the disk applied to the optical disk according to the present invention.

As shown in FIG. 3, it can be seen that the jitter ratio increases in proportion to the pressure applied to the optical disk and the rotation speed of the optical disk.

After such a scratch test, a focusing error, which is a symbol error rate (SER) or a bit error rate (BER) and a servo error signal, in addition to jitter, is evaluated as a dynamic characteristic evaluation item of the optical disk 20. Mechanical durability inspection of the surface of the optical disc may be performed through a tracking error or the like.

As shown in FIG. 4, a predetermined scratch pattern is increased on the surface of the optical disk 20 by the scratch unit 30 contacted according to a predetermined pressure and a rotation speed.

As shown in FIG. 4, a predetermined scratch pattern is formed on the optical disc using the microscratch tester according to the present invention, and the resulting scratch depth is obtained.

5 is a view showing the scratch depth generated according to the pressure applied to the optical disk according to the present invention through an experimental value. Bare discs and hard-coated discs are used as experimental values.

Through the experiment as shown in FIG. 5, when a scratch depth of more than 2 μm is generated, it is measured that a servo error is caused when the dynamic characteristics of the optical disc are evaluated.

That is, when the durability test of the surface of the optical disc, the 2μm is defined as an absolute reference value for evaluating the defect and good quality of the optical disc, and the steel wool test condition that causes the scratch depth of 2 μm is found and the mechanical durability of the optical disc surface is improved under this condition. The test will quantify the occurrence of scratches.

6 is a graph showing the scratch depth with pressure for quantifying the mechanical durability test method of the surface of the optical disk according to the present invention.

As shown in Figure 6, in the steel wool test using the type of steel wool # 000, and in the condition that the rotation speed of the optical disk only once, the pressure condition that the scratch depth causes a depth of 2㎛ can be seen that 1kgf / ㎠ have.

According to the quantified condition as described above, the contact pressure between the optical disc 20 and the scratch unit 30 is maintained at a predetermined pressure in proportion to the rotational speed of the optical disc, and then the optical disc is moved through the vertical movement of the scratch unit 30. Scratch part 30 in contact with 20 is spaced apart (S40).

At this time, by reducing the rotational speed of the optical disk to less than five times to reduce the wear of the optical disk by the scratch unit 30, it may cause a scratch very close to the scratch that can occur in real life.

That is, the scratches that may occur on the optical disk in real life are generated in one or two scratches, while the number of scratches on the scratch unit 30 increases through the rotation of the optical disk, and the shape is due to the wear of the peripheral optical disk that is scratched. The real difference between the scratches that occur in real life.

Accordingly, a problem arises in the reliability of the mechanical durability inspection of the optical disk surface due to scratches, which is the biggest problem that occurs in the mechanical durability inspection of the conventional optical disk surface.

In the present invention, the rotational speed of the optical disk can be reduced from one time to as many as less than five times through the quantified absolute reference value, thereby creating a scratch of the form closest to the scratches that can occur in real life, thereby improving the mechanical durability of the optical disk surface. The reliability of the test can be increased.

As described above, FIG. 6 shows that the scratch is generated using only 1kgf / cm 2, which is the pressure condition that the scratch depth causes the depth of 2 μm through only one optical disk rotation, and then the scratched optical disk 20 is separated from the rotating plate 10. The durability is inspected through scratches generated on the surface of the optical disc 20. Then, the defect and the good quality of the optical disk 20 is distinguished (S50).

Next, another optical disk to be inspected is placed on the rotating plate 10 to repeat the operation to distinguish between defective and good products of the optical disk.

The apparatus and method for testing the mechanical durability of the optical disk surface according to the present invention as described above has the following effects.

First, the surface mechanical characteristics can be improved by quantifying the occurrence information of scratches, thereby further increasing data retention due to the high density implementation of the optical disk.

Second, since the quality of the optical disk can be inspected easily and accurately, it is possible to increase the reliability.

Third, by using the scratch portion as steel wool (steel wool), it is possible to form as many scratches as desired in a short time, there is an effect that can reduce the manufacturing cost while reducing the test time according to the mechanical durability inspection of the optical disk surface. .

Those skilled in the art will appreciate that various changes and modifications can be made without departing from the spirit of the present invention.

Therefore, the technical scope of the present invention should not be limited to the contents described in the embodiments, but should be defined by the claims.

Claims (18)

A rotating plate for placing the optical disc and rotating the optical disc for a predetermined rotation speed through a rotational movement; And a scratch unit for applying a predetermined load in contact with the optical disc to generate a scratch on the surface of the optical disc. The method of claim 1, The scratch portion and the holding area, A good or defective inspection apparatus for an optical disc, characterized in that it comprises a scratch area in contact with the optical disc. The method of claim 2, The scratch region is good or bad inspection apparatus of the optical disk, characterized in that consisting of steel wool (steel wool). The method of claim 3, wherein The steel wool is good or bad inspection apparatus of the optical disk, characterized in that consisting of any one of # 0, # 00, # 000, # 0000. The method of claim 1, The rotating plate is a good or bad inspection apparatus of the optical disk, characterized in that further comprises a motor at the bottom. The method of claim 1, Pre-set load is good or bad inspection device of the optical disk, characterized in that the load of 50gf / ㎠ or more and 5000gf / ㎠ or less. Placing an optical disk on the rotating plate; Rotating the optical disk with the rotating plate; Applying pressure by using a scratch unit while the optical disc rotates at a predetermined rotation speed to generate a scratch on the surface of the optical disc; And identifying the defective or defective product of the optical disc by using the jitter value of the scratched optical disc. delete The method of claim 7, wherein The predetermined pressure according to the scratch test is a good or bad judgment method of the optical disk, characterized in that the pressure is set to 50gf / ㎠ or less than 5000gf / ㎠. The method of claim 7, wherein the step of separating the defective and good quality If the scratch depth on the surface of the optical disc is greater than 0 μm but less than 2 μm, it is classified as good quality. If the scratch is greater than 2 μm on the surface of the optical disc, good quality is classified as defective. Or failure determination method. The method of claim 7, wherein The predetermined number of revolutions or failure of the optical disc, characterized in that the number of revolutions of the predetermined optical disk is five times or less. The method of claim 7, wherein The durability of the optical disc, the quality discrepancy or failure determination method of the optical disc, characterized in that the evaluation based on SER (Symbol Error Rate). The method of claim 7, wherein The durability of the optical disk, the good or bad judgment method of the optical disk, characterized in that the evaluation based on the BER (Bit Error Rate). The method of claim 7, wherein The durability of the optical disc can be evaluated by using a servo error signal. The method of claim 7, wherein The durability of the optical disc can be evaluated by using a tracking error signal. Placing a recording medium on the rotating plate, rotating the recording medium together with the rotating plate for a predetermined number of revolutions, and applying a predetermined pressure to the surface of the recording medium using a scratch unit to create a scratch on the surface of the recording medium. Using the test method, the method comprising determining the durability of the recording medium based on scratches of the surface of the recording medium, And whether the recording medium has a scratch resistance. The apparatus of claim 1, wherein the predetermined number of revolutions is five times. 17. The recording medium of claim 16, wherein the preset number of revolutions is five times.

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