JPH0125311Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to a surface inspection device, and particularly to a surface inspection device for a subject that masks the edges of the subject.

[Conventional technology]

Generally, this kind of surface inspection equipment scans and inspects the entire surface of the object to be inspected, but it is more efficient when continuously manufacturing sheet materials such as synthetic resin films and plates and inspecting their defects. In this case, it is best to inspect only the parts that will be used as products, without inspecting the parts that will be removed in the final process. Particularly in products such as photosensitive films where it is necessary to search for minute defects, it is necessary to reduce noise in unnecessary parts as much as possible to improve accuracy. Therefore, when inspecting a film whose surface is coated with a photosensitive emulsion, there are many uneven coatings at the edge portions on both sides, and this is generally removed when the film is manufactured into a product.

[The problem that the invention attempts to solve]

Therefore, there is a possibility that an object to be inspected, such as a web, being conveyed at high speed may meander (deviate in the width direction) at the inspection position, and at this time, the positions of both edges change. Therefore, it is necessary to detect the displacement of this edge portion and change the width of the mask accordingly.

However, with conventional devices that perform masking by detecting level changes in the video signal, depending on the threshold value, masking defects may occur, or the video signal may be erroneously masked when a large defect is detected on the web. There were some drawbacks, such as:

The surface inspection device of the present invention is designed to eliminate these drawbacks.

[Means to solve the problem]

The surface inspection device of the present invention includes a means for measuring the position in the width direction of an object moving in the longitudinal direction, a means for converting the output of this measuring means into a digital signal and adding it every unit time, and a large number of sensors. The output of the adding means is masked by a line-shaped detection section that is arranged in parallel in the width direction of the specimen and detects the surface condition of the specimen, an address counter that takes out the output from this detection section for each position, and a comparator. The present invention is characterized by comprising means for comparing with a width setting value, and a mask width setting circuit for controlling the mask width of the video signal from the linear detection section based on the comparison result of the comparator.

The means for measuring the position in the width direction of the subject moving in the longitudinal direction includes, for example, a tracking device that moves following the meandering of the subject, and a differential transformer having a movable iron core connected to the tracking device.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows the optical system in the surface inspection device.
A is a tungsten lamp that illuminates the subject, and is a light source such as a halogen lamp. B is an infrared transmission filter, C is a first condenser lens that effectively uses the amount of light, D is a cylindrical lens, E is a second condenser lens, F is a roll that conveys the subject,
G is the object passing through the surface of this roll F.
An object that is conveyed at high speed and has a coating on its surface, such as a web, H represents the area to be inspected illuminated by one light source, I represents a defect such as a scratch on the surface of the object, and J represents the object to be inspected. A detection lens that collects the reflected light from the surface of G, and a detection section K that consists of a line-shaped sensor such as a CCD or photodiode array made up of many photo elements, and from this detection section K, the object to be inspected is detected. When a defect location in area H is found, a video signal indicating the defect is extracted.

In this invention, as shown in Fig. 2, the web G
A tracking device 1 that moves by following the meandering of the Take out the width direction position of G as an analog signal and convert it into a voltage -
converted into a digital signal by a frequency converter 4,
This is measured by counter 5 for a unit time (constant period)
The average meandering amount is calculated for each unit time.

Further, an address counter 6 extracts the output of a line-shaped sensor of a detection unit K, which has a large number of sensors arranged in parallel in the width direction of the web G, for each position, and calculates the average meandering amount of the web G for each unit time. The comparator 7 then compares the set value with the mask width set value 8, controls the mask width setting circuit 9 according to the comparison result, and detects the edge of the video signal 10 from the detection section K with a width according to the comparison result. part 1
1 will be masked.

[Effect of idea]

According to the device of the present invention, miscellaneous information and unnecessary information existing at the edge portion are masked using only the edge position signal of the web regardless of changes in the video signal, so the drawbacks of the conventional method can be eliminated, and the setting values can be changed. Therefore, the mask width can be easily changed, and since the edge position signal of the web is converted into a digital signal and processed, there is little error due to line noise, and this makes it possible to easily change the width of the strip. It is possible to increase accuracy without inspecting unnecessary parts. Furthermore, the output of the address counter 6, which is necessary for driving the line sensor, can be used as is as an input to the mask width setting circuit, and there are great advantages such as the device being simplified.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram of the optical system of the surface inspection device, and FIG. 2 is its circuit diagram. 1... Tracking device, 2... Tracking device support stand, 3...
... Differential transformer, 3a ... Moving iron core, 3b ... Fixed coil, 4 ... Voltage-frequency converter, 5 ... Counter, 6 ... Address counter, 7 ... Comparator, 8 ... Mask width setter, 9... Mask width setting circuit, 10... Video signal, 11... Edge portion, A... Light source, B... Infrared transmission filter, C... First condenser lens, D... Cylindrical lens, E... Third 2 Condenser lens, F...Roll, G...Web, H...Test area, I...Defect location, J...Detection lens, K...
Detection unit.

Claims (1)

[Scope of utility model registration request] A means for measuring the position in the width direction of an object moving in the longitudinal direction, a means for converting the output of this measuring means into a digital signal and adding it every unit time, and a large number of sensors arranged in parallel in the width direction of the object. a linear detection section for detecting the surface condition of the object; an address counter for taking out the output from the detection section for each position; and means for comparing the output of the addition means with a mask width setting value using a comparator. and a mask width setting circuit for controlling the mask width of the video signal from the linear detection section based on the comparison result of the comparator.