JPH0450643A - Flaw detector - Google Patents

Abstract

PURPOSE:To prevent the occurrence of deviation in scanning position when a plane under inspection is deflected and turned by measuring the distance between an inspecting part and the plane under inspection at two points at both ends of scanning light, and correcting and driving the fluctuation of the scanning position due to the change in distance in secondary scanning direction in real time at both ends of the inspecting part. CONSTITUTION:This apparatus is composed of an inspecting part 1 which has CCD sensor and performs the main optical scanning and a secondary scanning part 25 and a secondary scanning part 26 which are in parallel to each other and drive the inspecting part 1 in the vertical direction. When a plane under inspection 24 is deflected and the distance between the plane under inspection 24 and the inspecting part 1 is changed, the incident position into the plane under inspection 24 is changed in response to the changing amount. Therefore, the deflecting amount of the plane 24 can be detected. When the driving of the inspecting part 1 is controlled in real time in response to the detection, the occurrence of scanning position deviation is prevented even if the plane under inspection is deflected and turned, and the stable detection can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a flaw inspection device, and particularly to a flaw inspection device that can be applied to high-speed inspection of large-area thin plates with a regular appearance such as solar panels. .

[Conventional technology]

As a conventional technique, for example, Japanese Patent Application Laid-Open No. 59-68653
There is an apparatus for inspecting flaws on the surface of an object as shown in the above publication.

FIG. 6 is a sectional view showing an example of a conventional flaw inspection device.

The flaw inspection device shown in FIG.
5, and a processing device 36 that performs appropriate processing depending on the amount of light received by the photoreceptor 35.

The laser beam oscillated from the laser oscillator 31 is transmitted to the modulator 32.
The laser beam is modulated and input into a collimator 33, where the laser beam is converted into parallel light and irradiated onto the surface of an object 37.

The irradiated light is reflected by the surface of the object 37.

The reflection angle of reflected light varies depending on the condition of the surface of the object. Under normal conditions with no scratches or dust on the surface, the reflection pattern of the reflected light will be within a certain area, but in abnormal conditions with scratches or dust on the surface, the reflected light will be scattered more. , the light is scattered outside the normal reflection pattern area.

Therefore, a light shielding body 34 having an area at least larger than the area of the pattern is provided on the reflected light pattern during normal operation to block the reflected light during normal operation, and a light receiving body 35 is provided outside of the light shielding body 34. When the object 37 is abnormal, only the abnormal reflected light scattered to the outside of the light shielding body 34 is received by the light receiving body 35.

The received light is appropriately processed by a processing device 36.

[Problem to be solved by the invention]

In the conventional flaw inspection apparatus described above, the angle of incidence of the scanning light on the surface to be inspected cannot be set at a right angle due to the arrangement of the light receiving system. Therefore,
When the surface to be inspected swings or rotates in a direction perpendicular to the surface, a shift occurs in the scanning position, resulting in a defective area that is not inspected.

[Means to solve the problem]

The flaw inspection device of the present invention has an inspection section comprising a light source, a main scanning means for scanning the light emitted from the light source with a rotating polygon mirror, and a light receiving means for receiving the reflected and scattered light of the scanning light on the surface to be scanned. and sub-scanning means having mutually parallel driving parts that individually activate both ends of the inspection section in the main scanning direction with axes parallel to the surface to be inspected, and a sub-scanning means having drive sections parallel to each other that actuate both ends of the inspection section in the main scanning direction individually, It is configured to include means for measuring the relative distance between the surface and the inspection section.

〔Example〕

Next, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a perspective view showing an embodiment of the present invention.

The flaw inspection apparatus shown in FIG. 1 includes an inspection section 1, a sub-scanning section 25 that is parallel to each other and drives the inspection section 1 in the vertical direction, and a sub-scanning section 26.

The inspection section 1 has three optical axes: a scanning light a, a distance detection light b5, and a distance detection light C.

FIG. 2 is a cross-sectional view showing a connecting portion between the inspection section 1, the sub-scanning section 25, and the sub-scanning section 26.

The inspection section 1 has one end connected to the sub-scanning section 25 and the rotation joint 2.
Connected by 1. The other end of the inspection section 1 is a sub-scanning section 2.
6 through a rotation joint 22 and a telescopic joint 23.

FIG. 3 is a perspective view showing the optical configuration of the inspection section 1 of the present invention.

The inspection unit 1 includes a laser oscillator 2, a collimator 3, a lens 4 that receives collimated light, a galvanometer mirror 5 that performs optical scanning on a surface to be inspected 24, and a condensing light scattered from the surface to be inspected. An inspection optical system consisting of a condensing lens 6, a mask 7, a light receiving sensor 8, and a measuring device 18 that inputs the output of the light receiving sensor, a laser oscillator 9, and a half mirror 10.
, a lens 11 that makes one of the two optical axes separated by the half mirror 10 enter the surface to be inspected 24 and the reflected light from the surface to be inspected, a one-dimensional CCD sensor 12, and a half mirror 10. a mirror 13 that receives another optical axis separated by the mirror 13 and directs it toward the surface to be inspected; a lens 14 that receives the light whose tip axis is reflected by the surface to be inspected; a one-dimensional CCD sensor 15; CCD sensor 12 and one-dimensional CC
The distance detection system includes a sub-scanning driver 16 and a sub-scanning driver 17 that respectively input the output of the D sensor 15.

Next, the operation will be explained step by step with reference to FIGS. 1 to 5.

The beam emitted by the laser oscillator 2 is sent to the collimator 3
The light becomes parallel light, passes through the lens 4, is deflected by the galvanometer mirror 5, and scans the surface to be inspected 24 at an incident angle of 45°. The light reflected from the surface to be inspected 24 is blocked by the mask 7.

During scanning, if there are scratches on the surface to be inspected 24, scattered light will be generated.
The light is condensed by a condensing lens 6 and enters a light receiving center 8,
An output corresponding to the amount of light is obtained from the measuring device 18.

The presence or absence of scratches can be inspected based on the magnitude of this output value from a preset value. At this time, by driving the sub-scanning sections 24 and 25 in a direction perpendicular to the scanning of the inspection section 1 (Z direction), inspection within a two-dimensional plane can be performed.

On the other hand, the beam emitted by the laser oscillator 9 is separated into two optical axes by a half mirror 10. - The book is incident on the left end of the scanning light a on the surface to be inspected 24, and
The reflected light is passed through the lens 11 to the one-dimensional CCD sensor 1
2.

The other optical axis separated by the half mirror 10 passes through the mirror 13 and enters the right end of the scanning light a on the surface to be inspected 24, and the reflected light from the surface to be inspected 24 passes through the lens 14 and is
incident on the dimensional CCD sensor 15.

Here, if the distance between the surface to be inspected 24 and the inspection section 1 is constant, the outputs of the two one-dimensional CCD sensors 12 and 15 are both constant.

When the surface to be inspected 24 swings and the distance changes, the position of incidence on the surface to be inspected 24 changes according to the amount of change.
The incident position on the dimensional sensor 12 and the one-dimensional sensor 15 also changes, and the amount of deflection of the surface to be inspected 24 can be detected.

At this time, naturally, the position of incidence of the scanning light a on the surface to be inspected 24 also changes. For example, if the angle of incidence on the surface to be inspected 24 is 45°, and the deflection of the surface to be inspected 24 is l mm in the direction perpendicular to the surface, the amount of change δ in the incident position of the scanning light a
is δ=IXtan45°.

One-dimensional CCD sensor 12 and one-dimensional CCD at this time
The output changes of the sensor 15 are equal, and the sub-scanning driver 1
6 and the sub-scanning driver 17 perform equal sub-scanning speed control, thereby correcting the position change of the scanning light a due to the shake of the surface to be inspected 24.

Also, if the vibration of the surface to be inspected is in the direction of rotation with respect to the axis in the sub-scanning direction (Z direction), and the scanning length is 200 mm with a rotation angle of 1° centered on the right end of scanning light a, then No positional shift occurs, but at the left end 1, Q=200Xtanl.

Therefore, the amount of position change δ of the scanning light a is δ=Equation
45°=200Xtanl°Xtan45°Saki 3.5 (m-).

At this time, there is no change in the output of the one-dimensional CCD sensor 12, but 1
The dimensional CCD sensor 15 produces an output change according to the amount of shake of the surface to be inspected 24.

Two sub-scan drivers 18.17 and two one-dimensional CCDs
By driving each of the sensors 12 and 15 in response to changes in the output thereof and controlling the sub-scanning speed in the direction in which the inspection section 1 is tilted, it is possible to correct a change in the position of the scanning light a due to the shake of the surface to be inspected 24.

At this time, since the driving speeds of the two sub-scanning sections 25 and 26 vary, the inspection section 1 rotates within a plane defined by the two sub-scanning axes. The rotation at this time is received by the rotation joints 21 and 22, and the variation in the distance between the two sub-scan driving points is received by the expansion/contraction joint 23.

[Effects of the Invention] The flaw inspection device of the present invention measures the distance between the inspection section and the surface to be inspected at two locations on both ends of the scanning light, and changes the scanning position due to the change in distance in the sub-scanning direction at both ends of the inspection section. By correcting and driving in real time, it is possible to stably inspect flaws on large-area thin plates (for example, solar panels) that are difficult to install in a fixed manner.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an embodiment of the present invention, FIG. 2 is a sectional view showing the connection between the inspection section and the sub-scanning section, and FIG. 3 is an optical path diagram showing an embodiment of the inspection section of the present invention. FIGS. 4 and 5 are cross-sectional views showing the positional relationship of the surface to be inspected at the scanning position, and FIG. 6 is a cross-sectional view showing an example of the conventional method. 2.9...Laser oscillator, 3...Collimator, 4゜11.14...Lens, 5...Galvanometer mirror-6.
...Condensing lens, 7...Mask, 8...Light receiving sensor, 10...Half mirror 12, 15...1-dimensional CC
D sensor.

Claims (1)

[Claims] an inspection unit comprising a light source, a main scanning unit for scanning the light emitted from the light source with a rotating polygon mirror, and a light receiving unit for receiving the reflected and scattered light on the scanned surface of the scanning light; and a main scanning unit for the inspection unit. a sub-scanning means having mutually parallel driving parts that are activated individually at both ends of the direction with axes parallel to the surface to be inspected; and a relative relationship between the surface to be inspected and the inspection section at two ends of the inspection section. What is claimed is: 1. A flaw inspection device comprising means for measuring a distance.