JP2024083978A - Phase Adjustment System - Google Patents

Abstract

[Problem] To provide a phase adjustment system capable of conveying a metal substrate at high speed while adjusting the phase of the metal substrate as a conveying means so that continuous inspection is possible without stopping the conveying means. [Solution] The phase adjustment system comprises a phase detection unit having a conveying unit, a lighting device, and an imaging device, and a phase alignment unit having a first angle swing conveyor unit and a second angle swing conveyor unit that are driven independently of each other so as to convey the metal substrate at different conveying speeds, arranged side by side along a conveying path, the phase detection unit photographs a light beam that appears in a direction perpendicular to the rolling marks or grinding marks of the metal substrate with the imaging device and detects the angle that the axis of the light beam makes with respect to the direction of the conveying path, and the phase alignment unit adjusts the conveying speeds of the first angle swing conveyor unit and the second angle swing conveyor unit based on the angle to rotate the metal substrate horizontally on the conveying path, thereby aligning the angle within a predetermined range with respect to the conveying direction of the metal substrate. [Selected Figure] Figure 3

Description

The present invention relates to a phase adjustment system that rotates and transports a disk substrate cut from a rolled metal plate.

Disc substrates used in information storage devices such as hard disk drives are generally made of aluminum. In the manufacture of disk substrates, an aluminum alloy is rolled, and the rolled aluminum plate is punched into a disk shape to form a disk blank, which is then pressure annealed to flatten it and polished to a mirror finish to form a ground substrate (hereinafter also referred to as an aluminum substrate). The surface of this substrate is then nickel-phosphorus plated, polished to a mirror finish, and a media layer is then formed on top of it by sputtering.

If there are defects such as scratches or rust on the surface of the aluminum substrate, they cannot be removed even by polishing in the subsequent process, and the product may become defective. For this reason, the surface of the aluminum substrate is inspected.

An optical inspection device is generally used to inspect the surface of this aluminum substrate. An illumination device is used to illuminate the surface of the disk substrate that has been transported to the inspection device, and an image of the surface of the aluminum substrate is captured by an imaging device to determine whether or not there are any defects.

However, on the surface of the aluminum substrate transported to the inspection device, tiny streak-like irregularities called "rolling marks" that occur when the aluminum alloy is rolled, or "grinding marks" that occur when the substrate is ground to a mirror finish, are formed along one direction, and these irregularities affect the reflection of the illumination light. Because these rolling marks are not necessarily aligned in a fixed direction when the substrate is transported through the inspection device, the illumination light is scattered and reflected depending on the direction of the rolling marks, making it impossible to ensure contrast, and there is a problem that defects on the surface of the aluminum substrate cannot be accurately identified.

To address this issue, for example, Patent Document 1 proposes an inspection device that includes an illumination device that illuminates the aluminum substrate from multiple illumination directions and an imaging device that captures image data of the surface of the aluminum substrate illuminated from each illumination direction.

Patent document 2 also proposes a surface inspection device that uses multiple light sources projecting from different positions as a lighting device, a single line camera as an imaging means, and switches between the multiple light sources for each scan of the line camera to obtain and synthesize multiple different images with the single line camera.

JP 2012-047673 A JP 2000-162146 A

However, the inspection device described in Patent Document 1 requires a device or process for fixing or rotating the aluminum substrate during measurement, and it is not possible to continuously inspect the aluminum substrate without stopping the conveying means.

In addition, in order to perform highly accurate inspections with the inspection device described in Patent Document 2, it is necessary to increase the number of light sources in the illumination device, and furthermore, a large number of image correction processes must be performed according to the number of light sources, which makes it difficult to perform highly accurate inspections.

The present invention was made in consideration of these circumstances, and aims to provide a phase adjustment system that can transport metal substrates at high speed while adjusting their phase as a transport means, so that continuous inspection can be performed without stopping the transport means.

In order to solve the above problem, the inventors discovered that when light is irradiated onto a metal substrate having rolling marks or grinding marks, a light beam perpendicular to the rolling marks or grinding marks is generated, and thus the present invention was completed.

That is, in order to solve the above problem, the present invention provides a phase adjustment system as described below in [1].
[1] A phase adjustment system for rotating and conveying a metal substrate, comprising:
a conveying section that conveys the metal substrate along a conveying path;
a phase detection unit including an illumination device that irradiates light onto the metal substrate on the transport path, and an imaging device that images a light-irradiated surface of the metal substrate irradiated with the light;
a phase matching unit that arranges a first angle swing conveyor unit and a second angle swing conveyor unit that are driven independently of each other so as to convey the materials at different conveying speeds, side by side along the conveying path;
Equipped with
the phase detection unit captures an image of a light beam appearing in a direction perpendicular to the rolling marks or grinding marks of the metal substrate with the first imaging device, and detects an angle formed by an axis of the light beam with respect to a direction of the transport path;
the phase alignment unit adjusts the conveying speeds of the first angle swing conveyor unit and the second angle swing conveyor unit based on the angle to rotate the metal substrate horizontally on the conveying path, thereby aligning the angle within a predetermined range with respect to the conveying direction of the metal substrate.
Phase adjustment system.

Moreover, the phase adjustment system according to the present invention preferably has the configurations [2] to [3].
[2] The first angle swing conveyor section and the second angle swing conveyor section are
A drive motor;
a power transmission unit that transmits power from the drive motor to the drive pulley;
A plurality of conveyor belts each having a circular cross section and wound around the drive pulley and the plurality of driven pulleys;
The phase adjustment system according to [1],
[3] The phase adjustment system described in [1], wherein the first angle swing conveyor section and the second angle swing conveyor section further include a resin guide member having a guide surface extending along the transport direction so as to guide the outer peripheral surface of the metal substrate being transported.

According to the phase adjustment system of the present invention, the phase of a metal substrate having rolling marks or grinding marks is detected, and the metal substrate is rotated and transported according to the detected phase angle, so that the metal substrate can be transported with the phase aligned, allowing subsequent defect detection work, etc. to be carried out more smoothly.
Furthermore, according to the phase adjustment system of the present invention, the contact area with the metal substrate is reduced by using a conveyor belt with a circular cross section, while the load of the metal substrate can be distributed by using multiple conveyor belts. Therefore, even if the conveyor belt comes into sliding contact with the metal substrate during phase adjustment, the metal substrate can be transported at high speed without being damaged.

FIG. 1 is a schematic diagram showing the overall configuration of a surface inspection system according to the present invention. FIG. 2(a) is a schematic diagram showing a light beam appearing on the surface of a metal substrate, and FIG. 2(b) is a schematic diagram showing an angle α formed between the light beam and the conveying direction of the metal substrate. FIG. 3 is a top view showing the phase matching unit. FIG. 4 is a side view showing the phase matching portion.

A surface inspection system equipped with a phase adjustment device according to one embodiment of the present invention will be described below with reference to the drawings. This embodiment shows an example of the present invention, and the present invention is not limited to this embodiment. Various modifications and improvements can be made to this embodiment, and forms incorporating such modifications or improvements can also be included in the present invention.

As shown in Fig. 1, the surface inspection system 1 of this embodiment includes, in order from the upstream side in the conveying direction, a phase adjustment device and a surface inspection device. The phase adjustment device includes a carry-in section 10, a phase detection section 20, and a phase alignment section (phase adjustment conveyor) 30, and the surface inspection device includes a first defect inspection section 40, a second defect inspection section 50, and an unloading section 60. Each section will be described in detail below, but the surface inspection system 1 of the present invention inspects a grind substrate (disk-shaped aluminum substrate) that is cut out from a rolled aluminum plate and subjected to pressure annealing and grinding during the manufacturing process of a disk substrate for a HDD. Therefore, in Fig. 1, this aluminum substrate is shown as a metal substrate W.
In addition, in Fig. 1, each conveyor, which will be described later, is shown simplified with a pulley and a conveyor belt. Well-known conveyors are used for the carry-in conveyor 11, the inspection conveyor 43, the suction conveyor 51, the carry-out conveyor 61, and the sorting conveyor 62. Meanwhile, the phase adjustment conveyor 30, which is a feature of the present invention, is specifically shown in Figs. 3 and 4.
Furthermore, the carry-in unit 10, phase detection unit 20, phase alignment unit 30, first defect inspection unit 40, second defect inspection unit 50, and carry-out unit 60 are connected to the arithmetic processing device 100 by wire or wirelessly, and control is performed in each unit. Each of the units 10, 20, 30, 40, 50, and 60 may be provided with a separate control unit (not shown).

(Loading section 10)
In the carry-in section 10, ground substrates are stocked in a block form, and metal substrates W are taken out one by one from the stock using a suction collet or the like, and placed on a transport conveyor 11 for transport.
In addition, since the grind substrate requires extremely high flatness accuracy, the metal substrates W may be removed overlapping when pressed by suction. For this reason, discharge chutes 12 are provided above and to the sides of the transport conveyor 11 to discharge the overlapping metal substrates W.

(Phase detection unit 20)
The phase detection unit 20 is provided as a next process of the carry-in unit 10. That is, the phase detection unit 20 first receives the metal substrate W transported from the carry-in unit 10, and irradiates light from a ring illumination, which is a first illumination device 21, disposed above the metal substrate W. On the surface of the metal substrate W, streaky minute irregularities resulting from rolling, i.e., rolling marks (or grinding marks associated with mirror finishing by grinding) Wa, are formed, and when light is irradiated onto the surface of the metal substrate W, a light beam 15 perpendicular to the rolling marks Wa appears as shown in Fig. 2(a), and this light beam 15 is photographed by a CCD camera, which is a first imaging device 22.

Then, as shown in FIG. 2(b), the arithmetic processing device 100 calculates the angle α between the axis C1 of the beam of light 15 and the axis C2 of the transport direction of the metal substrate W.

(Phase Alignment Unit 30)
As the next step after the phase detection unit 20, a phase alignment unit (phase adjustment conveyor) 30 is disposed downstream of the carry-in conveyor 11. The phase alignment unit 30 is provided on both sides in the width direction of the conveying path, and includes a first angle swing conveyor unit 31 and a second angle swing conveyor unit 32 which are driven independently of each other so as to convey at different conveying speeds. Fig. 3 is a top view showing the phase alignment unit 30, and Fig. 4 is a side view thereof.

The first angle swing conveyor section 31 and the second angle swing conveyor section 32 each include a servo motor (drive motor) 31a, 32a attached to a housing 35, a power transmission section 33 such as a belt pulley that is disposed within the housing 35 and transmits power from the servo motors 31a, 32a to the drive pulley 34a, and multiple (in this embodiment, two) conveyor belts 37, 38 with a circular cross section that are wound around the drive pulley 34a and multiple driven pulleys 34b.

In addition, the first angle swing conveyor section 31 and the second angle swing conveyor section 32 are provided with a resin guide member 36 having a guide surface extending along the transport direction in a portion of the housing 35 facing the outer peripheral surface of the transported metal substrate W so as to guide the outer peripheral surface of the metal substrate W.

As a result, the transport speed of the first angle swing conveyor section 31 is adjusted by the rotation speed of the servo motor 31a, and the transport speed of the second angle swing conveyor section 32 is adjusted by the rotation speed of the servo motor 32a. In addition, by making the transport speeds of the first angle swing conveyor section 31 and the second angle swing conveyor section 32 different from each other, the metal substrate W rotates in a horizontal state while being guided by the guide surface of the guide member 36 and transported at high speed through the phase alignment section 30 in approximately 0.5 seconds.

That is, when the conveying speed of the first angle swing conveyor section 31 is made faster than that of the second angle swing conveyor section 32, the metal substrate W rotates clockwise in FIG. 2, and conversely, when the conveying speed of the second angle swing conveyor section 32 is made faster than that of the first angle swing conveyor section 31, the metal substrate W rotates counterclockwise in FIG. 2. Therefore, by adjusting the difference in conveying speed between the first angle swing conveyor section 31 and the second angle swing conveyor section 32 according to the angle α between the axis C1 of the light beam 15 detected by the phase detection section 20 and the axis C2 of the conveying direction of the metal substrate W, the angle α of the metal substrate W can be kept within a predetermined range.

Furthermore, the first angle swing conveyor section 31 and the second angle swing conveyor section 32 reduce the contact area with the metal substrate W by using the conveyor belts 37, 38 with a circular cross section, while the load of the metal substrate W can be distributed by using two conveyor belts 37, 38, so that the metal substrate W can be transported at high speed without being damaged even if the conveyor belts 37, 38 come into sliding contact with the metal substrate W during phase adjustment.

The rolling grain Wa of the metal substrate W transported from the transport unit 10 faces in various directions for each metal substrate W, and the angle α also has various values, but the phase alignment unit 30 ensures that the rolling grain Wa of all metal substrates W is substantially aligned in the transport direction. In this embodiment, the resolution of the angle α by the phase alignment unit 30 is ±2°, and the correction accuracy is within ±5°.

The phase alignment unit 30 also includes an upstream transmission sensor 39A and a downstream transmission sensor 39B on the upstream and downstream sides of the first angle swing conveyor unit 31 and the second angle swing conveyor unit 32, respectively.
Then, if the upstream transmission sensor 39A detects the introduction of the metal substrate W before the downstream transmission sensor 39B detects the removal of the metal substrate W, the first defect inspection unit 40 and the second defect inspection unit 50 described later will re-inspect the metal substrate W detected by the upstream transmission sensor 39A without inspecting it again, or without treating the inspection results as correct inspection, and send it to a subsequent process.

In this embodiment, the detection of the angle α by the phase detection unit 20 is performed when the metal substrate W is on the transport conveyor 11 of the loading unit 10, but it may also be performed when the metal substrate W is on the first angle swing conveyor section 31 and the second angle swing conveyor section 32 of the alignment unit 30. In this case, after the detection of the angle α by the phase detection unit 20 on the upstream side of the first angle swing conveyor section 31 and the second angle swing conveyor section 32, adjustment of the transport speed of the first angle swing conveyor section 31 and the second angle swing conveyor section 32 is started.

(First defect inspection unit 40)
1 , in the process next to the phase alignment unit 30, a first defect inspection unit 40 inspects defects on the surface of the metal substrate W. As an inspection method, a second illumination device 41 is disposed above an inspection conveyor 43, and a second imaging device 42 such as a CCD line camera disposed above the second illumination device 41 photographs the surface of the metal substrate W on the inspection conveyor 43, and the image is analyzed to check for the presence or absence of defects.
In addition, the second lighting device 41 and the third lighting device 52 described below use line-type lighting so that the entire width of the metal substrate W to be photographed by the second imaging device 42 and the third imaging device 53 can be illuminated.
In addition, since CCD line cameras are used for the second imaging device 42 and the third imaging device 53 described below, observation is possible as long as there is a gap of one line of the CCD array, and stable inspection is possible by scanning and combining the imaging results.

In addition, at this time, the direction of the rolling grain Wa of the metal substrate W is aligned by the phase alignment unit 30, so that diffuse reflection and dark field conditions do not occur in the camera image for all metal substrates W, making it possible to perform high-precision line inspection.

(Second defect inspection unit 50)
As described above, the detection of defects on the surface of the metal substrate W is completed, and as shown in Fig. 1, the metal substrate W transported by the inspection conveyor 43 after the inspection is sucked up and transported by the suction conveyor 51. Since the rolling marks Wa are formed in substantially the same direction on the front and back surfaces of the metal substrate W, the suction conveyor 51 sucks up the metal substrate W in the first defect inspection unit 40 upward while maintaining the angle aligned by the phase alignment unit 30, so that the metal substrate W can be transported with the rolling marks Wa aligned.

As shown in FIG. 1, in the second defect inspection section 50, while the metal substrate W is sucked upward by the suction conveyor 51, a third illumination device 52 arranged downstream of the inspection conveyor 43 and below the suction conveyor 51 irradiates light onto the rear surface of the metal substrate W, and a third imaging device 53 such as a CCD line camera photographs the rear surface of the metal substrate W, and the image is analyzed to check for the presence or absence of defects.

In this case, the rolling marks Wa are aligned on the back side of the metal substrate W just like on the front side, making it possible to perform high-precision line inspection.

(Transportation section 60)
The discharge section 60 is equipped with an output conveyor 61 which receives the metal substrate W that has been inspected for defects on its front and back surfaces and has been adsorbed by the suction conveyor 51, and a distribution conveyor 62 which is positioned downstream of the output conveyor 61 and distributes the metal substrate W discharged from the output conveyor 61 to three chutes.

As described above, the first defect inspection unit 40 and the second defect inspection unit 50 judge products to be non-defective, defective, or to be re-inspected when a normal inspection has not been performed or when a visual inspection is required. For this reason, the sorting conveyor 62 sorts the metal substrates W into non-defective, defective, and re-inspected products.

Therefore, in this embodiment, the metal substrate W can be inspected with high accuracy for defects in the ground substrate cut out by rolling a metal plate. Disk substrates that pass both inspections by the first defect inspection unit 40 and the second defect inspection unit 50 are nickel-phosphorus plated and polished in the usual manner, and a media layer is formed on top of it by sputtering.

The present invention is not limited to the above-described embodiment, and modifications and improvements can be made as appropriate.
For example, the phase adjustment conveyor of the present embodiment is not limited to application in surface inspection systems, but can also be applied to any system that requires a mechanism for rotating a disk-shaped metal substrate while transporting it.

1 Surface inspection system 10 Carry-in section (transport section)
15 Light beam 20 Phase detection unit 21 First lighting device (lighting device)
22 First imaging device (imaging device)
30 Phase adjustment unit (phase adjustment conveyor, transport unit)
31 First angle swing conveyor section 32 Second angle swing conveyor section 40 First defect inspection section 41 Second lighting device 42 Second imaging device 50 Second defect inspection section 51 Suction conveyor 52 Third lighting device 53 Third imaging device W Metal substrate Wa Rolling mark

Claims (3)

A phase adjustment system for aligning a direction of rolling marks or grinding marks of a metal substrate while rotating and transporting the metal substrate, comprising:
a conveying section that conveys the metal substrate along a conveying path;
a phase detection unit including an illumination device that irradiates light onto the metal substrate on the transport path, and an imaging device that images a light-irradiated surface of the metal substrate irradiated with the light;
a phase matching unit that arranges a first angle swing conveyor unit and a second angle swing conveyor unit that are driven independently of each other so as to convey the materials at different conveying speeds, side by side along the conveying path;
Equipped with
the phase detection unit captures an image of a light beam appearing in a direction perpendicular to the rolling marks or grinding marks of the metal substrate with the first imaging device, and detects an angle formed by an axis of the light beam with respect to a direction of the transport path;
the phase alignment unit adjusts the conveying speeds of the first angle swing conveyor unit and the second angle swing conveyor unit based on the angle to rotate the metal substrate horizontally on the conveying path, thereby aligning the angle within a predetermined range with respect to the conveying direction of the metal substrate.
Phase adjustment system. The first angle swing conveyor section and the second angle swing conveyor section are
A drive motor;
a power transmission unit that transmits power from the drive motor to the drive pulley;
A plurality of conveyor belts each having a circular cross section and wound around the drive pulley and the plurality of driven pulleys;
The phase adjustment system of claim 1 , The phase adjustment system according to claim 1, wherein the first angle swing conveyor section and the second angle swing conveyor section further include a resin guide member having a guide surface extending along the conveying direction so as to guide the outer peripheral surface of the metal substrate being conveyed.

Images