JPH0326447Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a surface defect detection device, and more particularly, to a surface defect detection device for various objects to be measured that has the ability to discriminate between surface defects and adhesion of foreign matter.

[Background of the idea]

Conventionally, an optical surface defect detection device has been used as a device for measuring surface defects of various objects to be measured. This device irradiates the surface of the object to be measured with light, and the light receiving element receives the reflected light of the irradiated light on the surface of the object to be measured.Based on the amount of received light, defects are detected on the surface of the object to be measured. It was configured to measure whether or not the test was successful.

However, as shown in the output waveform diagram of the light-receiving element shown in Figure 3, with conventional devices, defects such as scratches may occur on the surface of the object to be measured, even when dust or the like is attached to the surface of the object to be measured. There was a risk that even good products with no scratches or the like would be discarded as defective. Therefore, when inspecting using conventional equipment, it is necessary to re-inspect defective items manually or install a cleaning machine in the previous process to clean the surface of the object to be measured. It was being done. Therefore, when conventional devices are used to measure surface defects on objects to be measured, there are problems such as a decrease in yield, an increase in the number of re-inspection steps, or an increase in equipment investment.

[Purpose of invention]

The present invention was developed in view of the above circumstances, and it is possible to distinguish between surface defects such as scratches and adhesion of foreign matter such as dust, thereby making it possible to reliably detect truly defective products, thereby increasing yield. without reducing the
Moreover, it is an object of the present invention to provide a surface defect detection device that does not increase re-inspection man-hours or equipment investment requests.

[Summary of the idea]

The feature of the present invention is that the first optical system is composed of a first light projecting section that irradiates and scans the surface of the object to be measured, and a first light receiving element that receives reflected light from the surface of the object to be measured. a second light projecting section that irradiates light onto the surface of the object to be measured in a horizontal direction and scans in synchronization with the scanning of the first optical system; a second optical system including a second light-receiving element, and a signal processing section that combines both output signals from the first and second light-receiving elements of these optical systems to determine the quality of the surface. Therefore, in the case of surface defects such as scratches, the light emitted from the second light emitting part will not be attenuated and the output voltage of the second light receiving element will not decrease, but in the case of foreign matter adhesion, the light emitted from the second light receiving element will not be attenuated. All of these devices utilize the drop in output voltage to distinguish between surface defects such as scratches and adhesion of foreign matter such as dust.

[Example of idea]

Hereinafter, the present invention will be explained in detail based on the embodiments shown in the drawings.

Fig. 1 is a configuration diagram showing one embodiment of the present invention;
The figure is a diagram showing output waveforms of the first and second light receiving elements. The device according to the present invention includes a first optical system 1, a second optical system
It consists of an optical system 2 and a signal processing section 3 that receives output signals from both optical systems 1 and 2.
The first optical system 1 includes a laser light source 4 and a laser light source 4.
A first light projector 7 includes a vibrating mirror 5 that receives light from the object and irradiates the surface of the object to be measured 8 from above, a scanning lens 6 that scans the light from the vibrating mirror 5, and an object to be measured. The first light-receiving element 10 includes a condenser lens 9 that condenses light reflected from the surface of the condenser 8 and a light receiving element 10 that receives the light condensed by the condenser lens 9.
It is composed of a light receiving section 18.

The second optical system 2 includes a laser light source 11, a vibrating mirror 12 that receives light from the laser light source 11 and irradiates the surface of the object to be measured 8 in a horizontal direction, and a scanning lens 13 that scans the light from the vibrating mirror 12. A second light projecting section 14 comprising a second light projecting section 14, a condensing lens 15 that condenses the transmitted light emitted from the second light projecting section 14 and passing through the surface of the object to be measured 8, and the condensing lens 15. It is composed of a light receiving element 16 that receives the condensed light, and a second light receiving section 17 that is made up of a light receiving element 16 that receives the condensed light.
Reference numeral 19 indicates a synchronization unit, which controls the scanning of both optical systems 1 and 2 and the first light receiving element 1 of the signal processing unit 3.
Synchronize with the signal acquisition of 6.

Next, the action will be explained. Light irradiated onto the surface of the object to be measured 8 from the first light projecting section 7 of the first optical system 1 is reflected by the surface, and the reflected light enters the first light receiving section 18 . If the surface of the object to be measured 8 is scanned in this state, the amount of reflected light will be attenuated at locations where there are surface defects such as scratches or foreign matter adhesion, and the amount of reflected light will be attenuated at locations where there are surface defects such as scratches or where foreign matter is attached.
The output waveform diagram of the light receiving element 10 is as shown in the diagram. That is, the output voltage decreases at locations where there are surface defects or foreign matter adhesion.

On the other hand, the light irradiated horizontally onto the surface of the object to be measured 8 from the second light projecting section 14 of the second optical system 2 passes through the surface and enters the second light receiving section 17 . In this case, the passing light is attenuated only in the case of foreign matter adhesion, and the second
The output waveform diagram of the second light receiving element 16 shown in the figure is as shown in the figure. That is, the output voltage does not decrease at the surface defect portion, but only at the foreign matter adhesion portion. In the signal processing section 3, both light receiving sections 17 and 18
A part where the output voltage of the first light receiving element 10 decreases and the output voltage of the second light receiving element 16 decreases is determined as foreign matter adhesion, and only the output voltage of the first light receiving element 10 decreases. By detecting the parts that are scratched as surface defects such as scratches, it is possible to reliably distinguish between surface defects and foreign matter adhesion.

[Effect of idea]

According to the present invention, two optical systems are used to irradiate and scan the surface of the object to be measured from two directions, upward and horizontal, and the received light from these two directions is compared. , it is possible to reliably distinguish between surface defects such as scratches on the surface of the object to be measured and adhesion of foreign matter. Therefore, true defective products can be detected reliably, without reducing yield.
Moreover, there is no increase in re-inspection man-hours or capital investment.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram showing one embodiment of the present invention;
The figure shows the output waveforms of the first and second light receiving elements,
FIG. 3 is a diagram showing an output waveform in a conventional example. 1...First optical system, 2...Second optical system, 3...
Signal processing unit, 7...First light projecting unit, 8...Measurement object, 10...First light receiving element, 14...Second light projecting unit, 16...Second light receiving element, 17...Second Light receiving section, 18...first light receiving section, 19...synchronization section.

Claims (1)

[Scope of utility model registration request] The first step is to irradiate and scan the surface of the object to be measured.
a first optical system comprising a light projecting section and a first light receiving section that receives reflected light from the surface of the object to be measured; a second optical system comprising a second light projecting section that scans in synchronization with the scanning of the optical system and a second light receiving section that receives passing light emitted from the second light projecting section; A surface defect detection device comprising: a signal processing section that combines output signals from the first light receiving section and the second light receiving section to determine whether the surface is good or bad.