JP2003075355A - Device for inspecting defect - Google Patents

Abstract

PROBLEM TO BE SOLVED: To precisely detect defects of various kinds of inspected specimens. SOLUTION: A film 16 of the inspected specimen is irradiated with a light beam 17 by a projector 10. The light beam transmitted through the film 16 is photoreceived by a photoreceiver 20. A slit plate 22 and a lens 23 with a mask are provided in front of the photoreceiver 20. They are positioned selectively in a photoreceiving window 20c of the photoreceiver 20 by a shift mechanism 25. A mask photoreceiving system by the lens 23 with the mask or a slit photoreceiving system by the slit plate 22 gets selectable thereby. Which photoreceiving system a corresponding form belongs to is determined by a from specifying part 40, based on a form signal, and the shift mechanism 25 is operated to be brought into the photoreceiving system. The optimum photoreceiving system is selected in response to the form of the inspected specimen to detect the defect precisely.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection apparatus, and more particularly to irradiating an inspection object with inspection light, photoelectrically converting the irradiated inspection light by photoelectric conversion means, and based on an output signal of the photoelectric conversion means. The present invention relates to a defect inspection device for inspecting a defect of an inspection object.

[0002]

2. Description of the Related Art An object to be inspected such as a running web is irradiated with a light beam such as a laser and its transmitted light or reflected light is incident on a light receiver to detect various defects existing on the web from the light receiver. An apparatus for evaluating based on photoelectric conversion output is provided (for example, JP-A-59-220636).
JP-A-6-207910, JP-A-8-26194
No. 9).

Such a defect inspection apparatus for a web allows only normal light to enter a light receiver through a slit-shaped light receiving window,
It is roughly divided into two types: a slit light receiving method that detects defects by the output fluctuation and a mask light receiving method that masks normal light with a mask and allows only abnormal light to enter the light receiver and detects defects by increasing its output. To be done. The former method is an effective inspection method when a defect (concentration defect) such as a stain or a foreign substance, or a pinhole that causes a concentration change in the light beam is present in the inspection object. The latter method is an effective inspection method when there is a defect such as a colorless foreign substance or a scratch that scatters the light beam on the inspection object.

[0004]

Although the defect inspection apparatus based on the different light receiving methods has been provided as described above, only one of them is used in the manufacturing line. Therefore, when the inspection target is changed and the defect is inspected, it is necessary to install the optimum defect inspection device for each type of product each time, which is troublesome and makes it difficult to switch quickly. is there.

The present invention is intended to solve the above problems, and an object of the present invention is to provide a defect inspection apparatus capable of accurately detecting various defects even when the types of manufactured products are switched. To do.

[0006]

In order to achieve the above object, in the invention described in claim 1, a projector for irradiating the inspection object with the inspection light and a photoelectric conversion means for photoelectrically converting the irradiated inspection light are provided. A defect inspection apparatus for inspecting a defect of an object to be inspected based on an output signal of the photoelectric conversion means, wherein first inspection light passing means and second inspection light passage different in a method of passing the inspection light. And means for selectively setting them on the photoelectric conversion means.

The first inspection light passage means includes a mask for cutting normal light and a lens for allowing scattered light due to defects to be incident from above and below the mask and condensing on the photoelectric conversion means. Therefore, it is preferable that the second inspection light passing means has a slit. The inspected body is continuously run, the light projector scans the inspected light in a direction intersecting the traveling direction of the inspected body, and the setting means sets the first inspecting light transmitting means and the first inspecting light transmitting means. It is preferable that the inspection light transmitting unit 2 is moved in the traveling direction and one of the inspection light transmitting units is set to the photoelectric conversion unit. Furthermore, means for inputting the type signal of the inspection object, and identification means for specifying the first or second inspection light passing means to be set in the photoelectric conversion means based on the input type signal of the inspection object. It is preferable that the setting means sets the inspection light passage means specified by the specifying means to the photoelectric conversion means.

[0008]

FIG. 1 is a schematic diagram showing a main part of a defect inspection apparatus according to the present invention. The projector 10 includes a laser oscillator 11, a lens 12, mirrors 13a and 13b, a polygon mirror 14, and an optical sensor 15. The laser light (inspection light) emitted from the laser oscillator 11 has a predetermined diameter, for example, 0.33, on the surface of the film 16 as the inspected object that continuously travels in the direction of the arrow in the figure by the lens 12.
It becomes a light beam 17 of mm. Then, the light beam 17 is reflected by the polygon mirror 14 which rotates at a high speed in the clockwise direction, thereby scanning the film 16 in the width direction. The optical sensor 15 receives the light beam 17 immediately before the light beam 17 scans the film 16 and outputs a base point passage signal that serves as a reference for setting the inspection width.

In order to receive the inspection light transmitted through the film 16, a light receiver 20 extending in the scanning direction of the light beam 17 is provided. An inspection method switching means 21 is arranged on the front surface of the light receiver 20. The inspection method switching means 21 includes a slit plate 22 as a first inspection light passing means.
And a lens 23 with a mask as a second inspection light passing means.
A holding plate 24 for holding these in parallel with the film transport direction, and a shift mechanism 25 for shifting the holding plate 24 in the film transport direction. The slit light receiving method using the slit plate 22 and the mask With lens 2
3 is selectively switched to the mask light receiving method.

As shown in FIG. 2, the slit plate 22 is arranged so as to form a gap 22c by a pair of slit plate bodies 22a and 22b. Due to this gap 22c,
A slit opening 30 parallel to the scanning direction of the light beam 17 is formed. Through the slit opening 30, the film 16
A part 17 a of the light beam 17 that has passed through is incident on the light receiver 20. In the slit light receiving method using the slit plate 22, the defect detection capability is improved with respect to an inspection object having a relatively low reflectance, such as a photosensitive material for offset printing.

As shown in FIG. 3, the lens with mask 23
Is formed by forming a belt-shaped mask 23b on the incident surface of the cylindrical lens body 23a, and normal light is blocked by this mask 23b and does not enter the light receiver 20. Further, in the case of the light beam 17 that has passed through the defect, since it is diffused by the defect, this diffused light 17b enters the cylindrical lens body 23a from above and below the mask 23b as shown by the chain double-dashed line in the figure, Thereby, the light is focused on the light receiver 20. In the mask light receiving system using the lens with a mask 23, a test object having a high reflection efficiency, such as glossy paper, or a test object having high transparency, such as a film made of cellulose triacetate (TAC) or polyethylene terephthalate (PET), is used. The defect detection capability is improved.

As shown in FIG. 4, the shift mechanism 25 comprises a bracket 26, a guide member 27, and an air cylinder 28. The shift mechanism 25 is provided at both ends of the holding plate 24. The bracket 26 is a holding plate 24
Two guide pins 2 are attached to both sides of the
6a. The guide member 27 has a guide groove 27a.
Is formed, and the guide pin 26a is inserted in the guide groove 27a. The air cylinder 28 is arranged in the guide member 27, and the tip of the plunger is fixed to the bracket 26.

The air cylinder 28 is pneumatically driven by a switching device 38, and the slit plate 22 or the masked lens 2 is used.
Any one of 3 is set on the scanning line 39 of the light beam 17. The switching device 38 has a drive valve 38a, and the drive valve 38a is switched based on a product type switching signal from the product type specifying section 40. As a result, the slit plate 22 or the lens with mask 23 suitable for the product type is set, and the inspection method is switched.

The type identifying unit 40 selects either the slit light receiving system or the mask light receiving system according to the type of product to be manufactured. For this reason, each type is stored by being divided into two groups, a slit light receiving method and a mask light receiving method. In the present embodiment, the slit light receiving system group includes an inspection object having a relatively low reflectance, such as a photosensitive material for offset printing. Further, the mask light receiving system group includes inspection objects having high reflection efficiency, such as glossy paper, and inspection objects having high transparency, such as TAC and PET film. Note that the above grouping is an example, and in addition to these, if the defect detection capability is improved by each light receiving method, those types may be added to each group.

A cylindrical lens, a light guide rod, and a scattering band are arranged in the light receiver 20, and light receiving elements 20a and 20b are provided at both ends as shown in FIG. Then, the laser light that has entered the light receiving window 20c is collected by the cylindrical lens, passes through the light guide rod, enters the scattering band, and is reflected. Part of the light reflected by the scattering band is transmitted to the end surface of the light guide rod, and the light receiving elements 20a, 20
Enter 0b.

When the product type signal is a mask light receiving system such as glossy paper, TAC, PET or the like, the air cylinder 28 shifts the holding plate 24 downward through the switching device 38 so that the masked lens 23 is placed in front of the light receiving window 20c. Located in. If the film 16 has no defects such as scratches, the film 16
The light beam 17 that has passed through passes through the mask as it is, hits the mask, the light beam 17 does not reach the light receiving window 30a, and the output level of the light receiver 20 becomes a predetermined value or less. On the other hand, when the film 16 has a defect, the light beam 17 is refracted and diffusely reflected and dispersed in this portion. Therefore, the light beam 17 enters not only the mask 23b but also the lens body 23a from above and below the mask 23b, and the light beam 17b reaches the light guide rod in the light receiver 20. In the light receiver 20,
A cylindrical lens, a light guide rod, and a scattering band are arranged, and light receiving elements 20a and 20b are provided at both ends. Then, the light beam 17b that has entered the light receiving window 20c is collected by the lens body 23a, passes through the light guiding rod, enters the scattering band, and is reflected. Part of the light reflected by the scattering band is transmitted to the end surface of the light guide rod, and the light receiving elements 20a, 20
Enter 0b.

Further, when the product type signal is a slit light receiving system such as a photosensitive material for offset printing, the air cylinder 28 shifts the holding plate 24 upward through the switching device 38 to move the slit plate 22 to the front surface of the light receiving window 20c. Located in. In this case, if there is a defect, the light beam 1
7 is absorbed and strengthened. Therefore, the light beam is absorbed,
By strengthening, by identifying the absorption and strengthening portion, the defect of the film 16 in a product having a relatively low reflectance such as a photosensitive material for offset printing can be accurately detected.

As shown in FIG. 6, the light receiving elements 20a, 20a
The photoelectric conversion signal of b is sent to the defect signal generation unit 50, where it is signal-processed and a single defect signal is output. First, the light receiving elements 20a and 20b that receive the laser light are
The photoelectric conversion signals corresponding to the light quantity of the laser light are output, and these are supplied to the AGC circuit (auto gain control circuit) 51. The AGC circuit 51 not only adds photoelectric conversion signals from the light receiving elements 20a and 20b, but also outputs a light beam 1 to a normal film 16 having no defect.
When 7 is scanned and its light beam 17 is made incident on the light receiver 20, the photoelectric conversion signal is amplified so that the output signal becomes a constant level regardless of the position of the scanning center line. Further, even if a power fluctuation occurs due to deterioration of the laser oscillator 11 or the like, the AGC circuit 51 compensates for it. Furthermore, A
The GC circuit 51 is provided with a gain adjustment knob,
The gain value can be changed by operating this knob. The gain value is changed when the light receiving system is switched.

The signal from the AGC circuit 51 is input to the filter circuit 52 including a bandpass filter. The filter circuit 52 removes the low frequency and high frequency noise signals superimposed on the signal and outputs the signal to the binarization circuit 53. The binarization circuit 53 binarizes the signal according to the threshold value. As a result, the signal is binarized into a defect signal that becomes high level when the signal level becomes lower than the threshold value and a normal signal that becomes low level otherwise. The evaluation signal composed of these signals is the AND circuit 54.
Entered in.

On the other hand, the optical sensor 15 outputs a base point passage signal at a constant timing before the scanning of the light beam 17 is started,
This base point passing signal is input to the inspection width setting circuit 55.
The inspection width setting circuit 55 is based on the inspection width data and the number of lanes set in advance corresponding to the width dimension of the film 16, and the inspection width signal that becomes a high level for each lane width with the base point passing signal as a reference. Is output. Then, this inspection width signal causes the AND circuit 54 to be in the gate open state. Therefore, when a defect signal appears during the period when the inspection width signal is at the high level, the AND circuit 54 outputs the defect signal. The lane divides one scanning line into a plurality of sections.

The defect signal thus obtained is sent to the defect data processing device 60. Defect data processing device 6
At 0, the defect position is specified based on the single defect signal. The one-shot defect and its position information are sent to the defect image processing device 61 and displayed on the display thereof, and are also stored in the memory 60a in the defect data processing device 60 to be subjected to various data processing. . The data-processed defect information is referred to when a product such as a film is processed, and is used so that various defects are not included in the final product. In addition, it is also used as defect information for pursuing the cause of defects and as feedback information on the manufacturing line. Further, a defect image may be captured, each defect and its image may be associated with each other based on the defect and its position information, and the defect and its image may be displayed on the display.

In the above embodiment, the parameters of each circuit of the defect signal generator 50 are changed in response to the switching of the light receiving system to generate the defect signal suitable for the light receiving system. Instead of changing, the defect signal generating section dedicated to each light receiving method may be individually provided and these may be switched and used.

In the above embodiment, the light transmitted through the object to be inspected such as the film 16 is guided to the light receiver 20 to inspect for defects, but instead of this, as shown in FIG. The present invention may be applied to the defect inspection apparatus 70 of the type in which the film 16 is irradiated with the light beam 17 of 1. and the defect signal is obtained from the reflected light 17c. In this case, the inspection method switching means 2 is provided on the optical path of the reflected light 17c.
1 and the light receiver 20 are installed to detect various defects based on the reflected light 17c. The same components as those in the above-described embodiment are designated by the same reference numerals, and duplicate description is omitted.

Further, in the above embodiment, the slit plate 22
The lens 23 with a mask and the masked lens 23 are provided on the holding plate 24, and the holding plate 24 is moved in the transport direction of the film 16 by a driving device such as an air cylinder 28. However, the moving direction and the moving means are limited to those of the above-described embodiment. Not done. For example, in addition to other driving means such as a motor, the driving means may be omitted and the lens with a mask or the slit plate may be manually set at the light receiving position.

In the above embodiment, the holding plate is provided with one kind of slit plate 22 and masked lens 23. In addition to this, a plurality of kinds of slit plate and masked lens having different slit widths, mask opening widths and the like are provided. Are installed in parallel,
The light receiving window of the light receiving device may be set to have a slit width and a mask opening width that are most suitable for the product type.

[0026]

According to the present invention, the first inspection light passing means and the second inspection light passing means, which are different in the method of passing the inspection light passing through or reflected by the object to be inspected, are provided. Since the photoelectric conversion means is selectively set, the optimum inspection method can be selected according to the inspection object, and the defect can be accurately detected according to the inspection object of each type.

The first inspection light passing means comprises a mask for cutting normal light, and a lens for making scattered light due to a defect incident from above and below the mask and condensing it on the photoelectric conversion means. Since the second inspection light passing means is provided with the slit, it is possible to inspect the defect by selecting two light receiving methods, a mask light receiving method and a slit light receiving method.

The object to be inspected is continuously run, and the projector is
The inspection light is scanned in a direction intersecting the traveling direction of the inspection object, and the setting means moves the first inspection light transmitting means and the second inspection light transmitting means in the traveling direction, Since any one of the inspection light transmitting means is set in the photoelectric conversion means, it is possible to perform a defect inspection by two light receiving methods without using a plurality of projectors or light receivers,
The configuration can be simplified. Moreover, it is possible to easily switch between the two light receiving methods, and it is possible to easily cope with a change in product type.

Means for inputting the type signal of the object to be inspected, and specifying means for specifying the first or second inspection light passing means to be set in the photoelectric conversion means based on the input type signal of the object to be inspected. Since the inspection light passing means specified by the specifying means is set in the photoelectric conversion means by the setting means, the defect can be automatically inspected by the optimum light receiving method according to the type of the object to be inspected. .

[Brief description of drawings]

FIG. 1 is a perspective view showing a main part of a defect inspection apparatus of the present invention.

FIG. 2 is a sectional view of an essential part showing a slit light receiving system.

FIG. 3 is a sectional view of an essential part showing a mask light receiving system.

FIG. 4 is a front view showing an inspection method switching means in a state where the inspection method is switched to the slit light receiving method.

FIG. 5 is a front view showing the inspection method switching means in a state where the inspection method is switched to the mask light receiving method.

FIG. 6 is a block diagram showing an example of a defect signal generator.

FIG. 7 is a schematic diagram showing a reflection type defect inspection apparatus.

[Explanation of symbols]

10 Floodlight 11 Laser oscillator 13a, 13b mirror 14 polygon mirror 15 Optical sensor 16 films 17 light beams 20 light receiver 21 Inspection method switching means 22 Slit plate 23 Lens with mask 24 holding plate 25 shift mechanism 30 slit openings

Claims (4)

[Claims] 1. A light projector for irradiating an inspection object with inspection light,
Having a photoelectric conversion means for photoelectrically converting the irradiated inspection light,
In a defect inspection apparatus for inspecting a defect of an inspection object based on an output signal of the photoelectric conversion means, a first inspection light passage means and a second inspection light passage means, which are different in the passage method of the inspection light, A defect inspection apparatus comprising: setting means for selectively setting these in the photoelectric conversion means. 2. The first inspection light passing means includes a mask for cutting normal light, and a lens for allowing scattered light due to a defect to be incident from above and below the mask and condensing on the photoelectric conversion means. 2. The defect inspection apparatus according to claim 1, wherein the second inspection light passing means is provided with a slit. 3. The inspection object is continuously run, the light projector scans the inspection light in a direction intersecting the traveling direction of the inspection object, and the setting means transmits the first inspection light. 3. The defect inspection apparatus according to claim 1, wherein the inspection light transmitting means and the second inspection light transmitting means are moved in the traveling direction, and one of the inspection light transmitting means is set to the photoelectric conversion means. 4. A means for inputting a type signal of a device under test,
And a specifying unit that specifies the first or second inspection light passing unit to be set in the photoelectric conversion unit based on the input type signal of the object to be inspected, and the setting unit is specified by the specifying unit. The defect inspection apparatus according to claim 3, wherein the inspection light passing means is set to the photoelectric conversion means.