JP2002228436A - Device for measuring thickness of disk substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten measuring time while securing high reliability and to easily and inexpensively improve accuracy in measuring the thickness of a substrate. SOLUTION: This device for measuring the thickness of a disk substrate is provided with a pair of probes 3a and 3b opposed in such a way as to sandwich the disk substrate S for sensing contact with substrate surfaces, a probe drive means 4 for bringing the pair of probes 3a and 3b close to and separating them from the disk substrate surfaces, linear gauges 5a and 5b each for measuring the amount of movement of the probes 3a and 3b from a standby location to contact with the disk substrate surface, a slider 6 for moving the pair of probes 3a and 3b in the radial direction of the disk substrate S, a disk stage 7 for holding the disk substrate S through the use of its center hole (h) in such a way as to be freely and intermittently rotated, and a display unit 8 for outputting a measured value of the substrate thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention belongs to the technical field of a disk substrate thickness measuring device, and relates to a disk substrate thickness measuring device for measuring a substrate thickness by bringing a member into contact with a disk substrate surface.

[0002]

2. Description of the Related Art An optical disk such as a DVD has a structure in which a recording layer and a protective layer are formed on a resin disk substrate. Then, information is read out by rotating the optical disk at high speed in the drive device. At this time, if the thickness of the optical disc is not uniform, a runout occurs during rotation, and information cannot be read correctly. Therefore, it is first required that the thickness of the original disk substrate be uniform. In particular, in the case of an optical disk having a structure in which two disk substrates are bonded together, the thickness of the disk substrate is required to be uniform on the order of microns.

[0003] Incidentally, the disk substrate generally comprises:
The stamper is made by injection molding using a stamper made of nickel or the like as a mold, but the stamper wears out as the molding cycle is repeated. As a result, the thickness of the disk substrate varies. Therefore, conventionally, the thickness of the disk substrate is measured, and whether or not the thickness is within a predetermined range is strictly managed.

Conventionally, as a method of measuring the substrate thickness of the disk substrate, a distance from the reference plane to the disk substrate surface is measured by placing the disk substrate on a reference plane and manually applying a gauge to a plurality of locations on the disk substrate surface. Was to be done. In addition, laser light is applied to a plurality of locations on the surface of the disk substrate, and the distance from the reference plane to the surface of the disk substrate is measured from the reflected light.

[0005]

However, in the manual measurement, the reliability of the measured value is poor because it depends on the skill of the worker. In addition, it takes a lot of time to measure a plurality of locations on the disk substrate, and there is a limit to improvement in work efficiency. Therefore, it is difficult to reduce the measurement time while securing high reliability in the manual measurement.

On the other hand, in the case of using a laser beam, the distance is calculated on the basis of the laser wavelength unit. Therefore, a distance calculating unit based on the laser wavelength is required in addition to the reflected light receiving unit. Since this calculating means requires a circuit and a program for performing complicated calculations, the measuring device has a complicated configuration as a whole and is expensive in terms of cost. Further, in order to require a measurement accuracy of a micron or less, it is necessary to use a high-frequency laser beam having a short wavelength, and if peripheral components are included for improving the measurement accuracy, the cost will be further increased. Therefore, it has been difficult to easily and inexpensively improve the measurement accuracy with a measuring device using laser light.

The present invention provides a "disk substrate thickness measuring apparatus for measuring a substrate thickness by bringing a member into contact with a disk substrate surface".
It is an object of the present invention to reduce the measurement time while ensuring high reliability, and to improve the measurement accuracy of the substrate thickness easily and inexpensively.

[0008]

Means for Solving the Problems Technical means of the present invention taken to solve the above problems are as follows. "A pair of probes arranged opposite to each other with the disk substrate interposed therebetween and sensing contact with the disk substrate surface, and a probe that supports the pair of probes and moves each probe toward and away from the disk substrate surface. Driving means, measuring means for measuring the amount of movement of each of the measuring elements from the standby position to contact with the disk substrate surface, and measuring element slider means for moving the pair of measuring elements in the radial direction of the disk substrate. Substrate holding means for holding the disk substrate intermittently rotatable about its center hole, and output means for outputting the substrate thickness measured by the pair of tracing styluses over the entire circumference of the disk substrate. It is characterized by having. ] The technical means comprises:
It works as follows.

The measuring element driving means moves each measuring element close to the disk substrate surface, and when each measuring element comes into contact with the substrate surface, a sensing signal from each measuring element is transmitted to the measuring means. Thus, the measuring means measures the amount of movement of each tracing stylus, and the thickness of the substrate at the point sandwiched by the pair of tracing styluses is measured from the amount of movement. That is, the value of the substrate thickness is set such that the state of the limit of advance of each tracing stylus (the state in which the tips of each tracing stylus abut each other) is set to zero, and the movement amount is subtracted from the distance between the pair of tracing styluses. Either measurement is performed to obtain the substrate thickness, or the measured movement amount is subtracted from the distance between the pair of probes to obtain the substrate thickness.

Further, since the tracing stylus slider means moves the pair of tracing stylus in the radial direction of the disk substrate, the substrate thickness can be measured at arbitrary plural points in the radial direction of the disk substrate. Moreover, since the substrate holding means enables the disk substrate to be intermittently rotatable,
The substrate thickness can be measured at arbitrary plural points in the circumferential direction of the disk substrate. As a result, by appropriately operating the tracing stylus slider means and the substrate holding means, the substrate thickness in the radial direction (for example, the inner position, the center position, and the outer position of the disk substrate) with respect to the entire circumference of the disk substrate, The substrate thickness in the circumferential direction of the substrate can be easily measured. Further, since the output means outputs the substrate thickness as a measurement result, the substrate thickness over the entire circumference of the disk substrate can be immediately confirmed.

[0011]

As described above, according to the present invention, the thickness of a substrate is measured by sandwiching a disk substrate between a pair of measuring elements, so that a highly reliable measurement value can be obtained in a short time as compared with the case of manual operation. can get. Moreover, the thickness of the substrate can be measured easily and at low cost as compared with the case of using a laser beam.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a plan view showing an overall configuration of a disk substrate thickness measuring apparatus according to an embodiment. The thickness measuring apparatus according to the present embodiment
This is an apparatus for measuring the thickness of a resin disk substrate obtained by injection molding using a stamper as a mold.

The disk substrate S has a disk shape as a whole and has a central hole h for holding a disk at the center (see FIG. 4). A recording layer and a protective layer are formed in a later step. Optical disk. The disk substrate S itself is made of a resin molded product such as polycarbonate, acrylic, polyester, epoxy, and acetal.

As shown in FIG. 1, the thickness measuring device 1
A disk stage 7, a pair of upper and lower probes 3 a and 3 b, a probe driving unit 4
And upper and lower linear gauges 5 a and 5 b and a slider 6. In addition, a display unit 8 and an operation unit 9 are provided at an upper portion of the apparatus main body 2.

The disk stage 7 holds the disk substrate S using its center hole h. The disk stage 7 includes, for example, a stage base 71 and a cap 72, as shown in FIG. The stage base 71 has a concave portion 711 having a predetermined depth from an upper surface portion,
A magnet m is arranged at the bottom of the concave portion 711. The cap 72 has a convex shape, and the lower convex portion 7
Reference numeral 21 is made of a material (for example, iron, nickel, or the like) that can be bonded to the magnet m. Further, the inner diameter of the concave portion 711 of the stage base 71 is
1 and almost coincides with the diameter of the center hole h of the disk substrate S. Accordingly, the disk substrate S is held by the stage 71 by inserting the projection 721 of the cap 72 into the recess 711 of the stage 71 with the projection 721 of the cap 72 inserted in the center hole h. . Then, the concave portion 71 of the stage base 71
Since the magnet m is arranged at the bottom of the magnet 1, the convex portion 721 of the cap 72 is adhered to the magnet m, and the disk substrate S on the stage table 71 is pressed by the cap 72 attracted to the magnet m. Thus, the disk substrate S is stably held on the stage table 71. The bottom of the recess 711 or the cap 7 so that the cap 72 does not apply a certain or more strong pressing force to the disk substrate S.
A spring is attached to the tip surface of the second convex portion 721 and the magnet m
(The pressing force on the disk substrate S) may be reduced.

The disk stage 7 is connected to a drive motor 76 to rotate the stage 71. Thus, the disk substrate S placed on the stage table 71 is intermittently rotated at predetermined angles. The rotation of the stage table 71 is, for example, as shown in FIG.
A belt 75 is bridged between a pulley 73 below the stage base 71 and a pulley 74 of the drive motor 76, and the drive motor 7
6 is transmitted to the stage base 71.
As the drive motor 76, for example, a servo motor,
A known motor such as a stepping motor can be used. Therefore, according to the disk stage 7, the disk substrate S
Is rotated intermittently at a predetermined angle, for example, the thickness of a plurality of rows of the disk substrate S at a predetermined angle in the circumferential direction such as eight rows at 45 degrees with respect to the entire circumference can be measured. .

The probes 3a and 3b are vertically opposed to each other with the disk substrate S interposed therebetween, and their tips are needle-shaped. These probes 3a, 3b
When the needle-shaped tip comes into contact with the disk substrate surface, a sensing signal is output. That is, the probes 3a and 3b function as sensors for detecting the contact of the disk substrate surface.

The probe driving means 4 moves the upper and lower probes 3a and 3b toward and away from the surface of the disk substrate S. The probe driving means 4 includes a driving motor 41 such as a servo motor, a driving cam 42 connected to the driving motor 41, and an upper and lower 2 which is connected to the driving cam 42 and supports the upper and lower probes 3a and 3b. And two drive arms 43a and 43b. The drive motor 4
The rotation of 1 rotates the driving cam 42, and this rotation is converted into linear motion by the driving arms 43a and 43b. As a result, the probes 3a, 3b supported by the drive arms 43a, 43b move up and down to move the upper and lower probes 3a, 3b toward and away from the disk substrate surface.

The linear gauges 5a and 5b are attached to the upper and lower probes 3a and 3b, respectively, and subtract the amount of movement of the probes 3a and 3b by the probe driving means 4 from the distance between the upper and lower probe tips. It is to measure. That is, the upper and lower linear gauges 5
a and 5b denote the amount of movement from the stand-by position where the upper and lower probes 3a and 3b are separated from the disk substrate surface to the contact position with the disk substrate surface, with the forward limit state where the leading ends contact each other is set to zero. Measurement is performed so as to subtract from the distance between the upper and lower probe tips at the standby position. That is, the probes 3a and 3b are gradually moved closer to the disk substrate surface by the probe driving means 4, and when the probes 3a and 3b come into contact with the disk substrate surface, a sensing signal is output from the probes 3a and 3b. This sensing signal is transmitted to the probe driving means 4 to instruct the probe driving means 4 to stop driving. Thus, the disk substrate surface is not deeply damaged by the probe. Further, the sensing signal is transmitted to the linear gauges 5a and 5b at the same time. Therefore, when the sensing signals are input from the probes 3a and 3b attached to the upper and lower linear gauges 5a and 5b, the subtraction measurement of the probe movement amount is stopped. In this way, the amount of movement of each probe 3a, 3b is subtracted from the distance between the tips of the probes, and the resulting value becomes the substrate thickness of the disk substrate S at the measurement point.

According to the linear gauges 5a and 5b, it is possible to give a precision of a micron unit, so that the substrate thickness can be measured with a high precision of a micron unit. In this example, each of the linear gauges 5a and 5b measures so that the movement amount of each probe 3a and 3b is subtracted from the distance between the upper and lower probe tips.
The substrate thickness may be determined by measuring the movement amounts of the probes a and 3b and subtracting the movement amounts of the probes 3a and 3b from the distance between the upper and lower probe tips by the calculating means.

The slider 6 allows the pair of upper and lower probes 3a and 3b to move in the radial direction of the disk substrate S held on the disk stage 7.
The slider 6 includes a U-shaped slider section 61, a rail section 62, and a driving section 63. The U-shaped slider 61 moves in the radial direction of the disk substrate S held on the disk stage 7 while keeping the relative positions of the upper and lower probes 3a and 3b constant. The rail section 62
Guides the U-shaped slider portion 61 to move in the horizontal direction. The driving unit 63 includes a servomotor and the like, and moves the U-shaped slider unit 61 along the rail unit 62 by driving the servomotor. It should be noted that a predetermined mechanical brake may be provided so that the probes 3a and 3b are stabilized when the thickness of the substrate is measured by the probes 3a and 3b. According to the slider 6, the pair of upper and lower probes 3a and 3b are
Therefore, for example, it is possible to measure the substrate thickness at a plurality of points such as an inner position, a center position, and an outer position in a desired radial direction of the disk substrate S.

The display unit 8 outputs and displays the value of the substrate thickness measured by the pair of probes 3a and 3b. As the display unit 8, for example, L
CD (Liquid Crystal Display) and CRT (Cathode-Ra
y Tube) and the like.
The substrate thickness measured at a and 5b is displayed. As an example of the display, for example, in addition to displaying all the measured values by the probes 3a and 3b, the maximum value and the minimum value may be displayed, and furthermore, the average value of a predetermined measurement range and the like may be displayed. It may be displayed.

The operation unit 9 includes a power switch of the thickness measuring device 1 and operation switches of the respective mechanisms. In the thickness measuring device 1, a storage unit for storing the measurement data in a predetermined file format, a transmission unit for transmitting the measurement data to a terminal device such as a personal computer installed separately, or a measurement data to a desired evaluation value Operation means for performing calculations may be provided.

According to the storage means, the past and present stored measurement data can be downloaded to the recording medium in a predetermined file format. Therefore, the measurement data is read out from the recording medium and the other terminal device collects the measurement data. Available to According to the transmission means, the measurement data can be directly transferred to another terminal device in a predetermined file format to the other terminal device, and can be immediately used for a totaling process and the like. Further, according to the arithmetic means, it is possible to make use of quality control, such as verification of the state of the stamper, based on desired tallying processing and comparison with past measurement data.

Next, an example of the operation of the thickness measuring device 1 will be described. In this example, as shown in FIG. 4, three rows of an inner position P1, a center position P2, and an outer position P3 are provided for eight rows L1 to L8 of 45 degrees each in the circumferential direction of the disk substrate S.
The substrate thickness at a point is measured, and a total of 24 points of the substrate thickness is measured. More specifically, the disk substrate S has a diameter of 120 mm and a center hole having a diameter of 15 mm. As a measurement position, the inner position P1 is 24 mm from the center.
, The center position P2 is a point 40 mm from the center, and the outer position P3 is a point 55 mm from the center.

As shown in FIG. 1, first, a power switch attached to the operation unit 9 on the apparatus main body 2 is turned on, and then the disk substrate S is mounted on the disk stage 7. In order to place the disk substrate S on the disk stage 7, the convex portion 721 of the cap 72 is fitted into the concave portion 711 of the stage base 71 with the convex portion 721 of the cap 72 passed through the center hole h of the disk substrate S ( See FIG. 2). Then, the magnet m disposed at the bottom of the concave portion 711 of the stage table 71 is magnetically bonded to the convex portion 721 of the cap 72, and thereby the disk substrate S is moved to the stage table 71.
And held between the cap 72.

Next, an instruction is given from the operation unit 9, the slider 6 is moved toward the center of the disk substrate S, and the pair of probes 3a and 3b are arranged at the inner position P1 of the disk substrate S (FIG. 3). See.). When the positioning of the probes 3a and 3b is completed, the probe driving means 4 is then driven to gradually bring the upper and lower probes 3a and 3b closer to the disk substrate surface. At this time, the upper and lower linear gauges 5a and 5b start measuring so as to subtract the movement amount of the attached probes 3a and 3b from the distance between the upper and lower probe tips at the standby position. The linear gauges 5a and 5b are set to zero when the forward end of the linear gauges 5a and 5b is in contact with each other.

When the tips of the probes 3a and 3b come into contact with the disk substrate surface, the probes 3a and 3b output sensing signals at the time of the contact. Then, the probe driving means 4 having received the sensing signal stops the approach movement of the probe 3a, 3b on the side outputting the sensing signal to the disk substrate S. Thus, the disk substrate S is not damaged by the probes 3a and 3b. At the same time, the linear gauges 5a and 5b also receive the sensing signal, and terminate the subtraction measurement of the probe movement amount. Thereby, the subtracted result value becomes the substrate thickness of the disk substrate S at the inner position P1.

Next, after the probe driving means 4 is driven to retract the probes 3a and 3b, the slider 6 is moved to dispose the probes 3a and 3b at the center position P2 of the disk substrate S. Then, the upper and lower probes 3a and 3b are moved close to each other until they come into contact with the disk substrate surface, and the thickness of the disk substrate S at the center position P2 is measured.

When the measurement of the substrate thickness at the center position P2 is completed, the probe driving means 4 is driven to drive each probe 3
After retracting a and 3b, the slider 6 is moved to dispose the probes 3a and 3b at the outer position P3 of the disk substrate S, and then approach the upper and lower probes 3a and 3b until they come into contact with the disk substrate surface in the same manner as described above. Then, the thickness of the disk substrate S at the outer position P3 is measured.

When the measurement of the substrate thickness at the three points of the inner position P1, the center position P2, and the outer position P3 is completed for the row L1, the probe driving means 4 is driven to move the probes 3a and 3b backward. After that, the slider 6 is driven to move the probes 3a and 3b to the disk substrate S.
(See the state shown in FIG. 3).

After retreating the probes 3a and 3b to the outer positions of the disk substrate S, the disk stage 7 is rotated by 45 degrees, and the next row L2 is moved to the inner position P in the same manner as described above.
1. Measurement of the substrate thickness at three points: the center position P2 and the outer position P3. In this manner, for eight rows L1 to L8 of 45 degrees each in the circumferential direction of the disk substrate S, the substrate thickness at three points of the inner position P1, the center position P2, and the outer position P3 is measured, and a total of 24 points is measured. Measure the substrate thickness.

The measured values of the substrate thickness at the 24 points are all output and displayed on the display unit 8 on the upper part of the apparatus main body 2, and the maximum value and the minimum value of the measured values of the substrate thickness at the 24 points are simultaneously output and displayed. You. Therefore, the operator can instantaneously determine whether or not the measured substrate thickness of the disk substrate S is within a predetermined standard range by looking at the substrate thickness measurement value displayed on the display unit 8. Thus, the measurement of the thickness of the disk substrate S is completed. After that, the disk substrate S is taken out from the disk stage 7 and sent to the next step.

As described above, according to the thickness measuring apparatus 1 of the above embodiment, the substrate thickness is measured by sandwiching the disk substrate S between the pair of probes 3a and 3b. Highly measured values can be obtained in a short time. In addition, since the substrate thickness is measured by the probes 3a and 3b and the linear gauges 5a and 5b, the substrate thickness can be measured more easily and at lower cost than in the case of using laser light.

In the above-described embodiment, the disk stage 7 is not limited to the one using the magnet m, but is fitted into the center hole h of the disk substrate S so that the disk stage 7
Any device that utilizes the center hole h of the disk substrate S, such as holding it on top, may be used. In addition, in the circumferential direction of the disk substrate S, 4
For 8 rows of 5 degrees each, inside position, center position,
Although the substrate thickness is measured at three points on the outer side, the present invention is not limited to this, and a desired point may be measured as appropriate. in addition,
The measurement may be performed in any order.

[Brief description of the drawings]

FIG. 1 is a plan view showing an overall configuration of a disk substrate thickness measuring apparatus according to an embodiment.

FIG. 2 is a schematic diagram showing a disk stage.

FIG. 3 is a schematic diagram showing a main part of the thickness measuring device.

FIG. 4 is a plan view showing measurement points on a disk substrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Thickness measuring device 2 Device main body 3 Probe 4 Probe driving means 5 Linear gauge 6 Slider 7 Disk stage 8 Display unit 9 Operation unit S Disk substrate h Center hole of disk substrate

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazumasa Kurahashi 11-260 Kugahoncho, Fushimi-ku, Kyoto F-term in U-Shin Seiki Co., Ltd. (Reference) 2F069 AA46 AA98 BB17 CC07 DD15 GG01 GG12 GG63 GG72 HH01 HH21 HH23 JJ06 JJ17 JJ19 MM32 MM34 QQ05 QQ07 5D121 AA02 HH04

Claims (1)

[Claims] 1. A disk substrate thickness measuring device for measuring a substrate thickness by bringing a member into contact with a disk substrate surface, comprising: a pair of disk substrate thickness measurement devices each of which is opposed to each other with the disk substrate interposed therebetween and senses contact of the disk substrate surface. A tracing stylus; a tracing stylus driving means for supporting the pair of tracing styluses to move each stylus toward and away from the disk substrate surface; and moving the stylus from the standby position to contacting the disk substrate surface. Measuring means for measuring the amount; measuring element slider means for moving the pair of measuring elements in the radial direction of the disk substrate; and substrate holding means for holding the disk substrate intermittently rotatable about its center hole. An output means for outputting a substrate thickness measured by the pair of tracing styluses over the entire circumference of the disk substrate.