JP2003083902A - Method and device for inspecting specimen - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for inspecting specimen by which a defective part can be inspected with accuracy without requiring any complicated scanning mechanism, expensive camera, etc., in other words, inexpensively with a simple structure and, in addition, which are favorable even to a specimen having a relatively narrow inspection width. SOLUTION: The device is provided with a light source 1 which emits inspecting light α upon a specimen 6, a first beam shaping means 11 which shapes the inspecting light α emitted from the light source 1 into a linear beam, and a second beam converging means which narrows the size of the inspecting light shaped into the linear beam in the lengthwise direction of the specimen 6. The device is also provided with a third beam converging means 3 which narrows the projected width W of the beam, a light receiving section 4 provided with a light shielding member 41 in a shielded section where the inspecting light transmitted through the normal part of the specimen 6 is made incident and received, and a signal processing section 5 which detects the defective part D of the specimen 6 by inputting the output signal of the light receiving section 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to optically detecting a defective portion such as a scratch formed on a test object such as a transparent or translucent film or a reflective sheet which is continuously transferred. The present invention relates to a method and an apparatus for inspecting a test object.

[0002]

2. Description of the Related Art For example, an inspection apparatus for inspecting an object such as a transparent or translucent film (in-line) transferred by a line for defects such as scratches on its surface. Are known.

As an inspection device of this type, for example, as described in JP-A-4-178545 and JP-A-2-83438, an inspection light is externally projected onto an object to be inspected and the object to be inspected. It is known that an inspection light transmitted through an inspection object is projected on a screen, and a projected image on the screen is made incident on and received by a light receiver such as a video camera. For example, Japanese Patent Laid-Open No. 4-178545 discloses a parallel light generator using a concave mirror together with a light source and a CCD.
A combination of a camera using a line sensor is disclosed, and JP-A-2-83438 discloses a combination of a pinhole light source and a two-dimensional camera such as a TV camera or a high resolution camera. Is disclosed.

As an inspection device of this type, for example, Japanese Patent Laid-Open No. 6-207910 and Japanese Patent Laid-Open No. 51-1261.
As described in Japanese Patent Publication No. 91, there is known a structure in which a laser spot is scanned and a light receiver receives the light. In particular,
Japanese Unexamined Patent Publication (Kokai) No. 6-207910 discloses a device in which the effective window width of a light receiver is smaller than that of a laser beam spot. The defective signal is configured to be emphasized / amplified by passing it a plurality of times.

[0005]

However, these inspection devices described above are provided with a complicated scanning mechanism on the light source side for inspecting a wide area by laser scanning, or a CCD camera as a light receiver. However, it has the drawback of being expensive because it uses
In addition, among these inspection devices, there are those in which a special mechanism is added to the scanning mechanism or a special device is added to the camera side in order to improve the detection accuracy, but the cost increases accordingly. It has the drawback. Further, in these inspection devices, even if the object to be inspected has a particularly narrow shape, the number of parts constituting the inspection device cannot be particularly reduced, so that the inspection width is inevitably high. It has the drawback that it will end up.

This situation is not limited to an inspection apparatus for detecting a defective portion of a transparent or semi-transparent test object, and for example, for an inspection apparatus for detecting a defective portion on an incident (reflection) surface. Is also the same and causes the same inconvenience.

In view of the above-mentioned circumstances, the present invention does not require a complicated scanning mechanism or an expensive camera, in other words, has a simple structure and a low cost to perform an accurate inspection of a defective portion. It is an object of the present invention to provide an inspection method and device for an object which can be inspected and which is convenient for inspecting an object having a relatively narrow inspection width.

[0008]

In order to achieve the above object, the method of inspecting an object of the present invention is such that the inspection light from a light source emitted toward the object is orthogonal to the width direction of the object. Forming a linear beam having a narrow length direction, projecting this linear beam onto a test object as inspection light, and selecting the test light from among the test lights incident on the test object. Only the inspection light that transmits or specularly reflects the normal part of the object is made to enter and receive the light-shielding region of the light-receiving portion that is shielded by the light-shielding member, and the inspection light out of the inspection light that is incident on the object is detected. Only the inspection light that is refracted or scattered at the defective portion is made to enter and receive light in the light receiving region of the light receiving portion where the light shielding member is not provided, and the light intensity or the light intensity of the inspection light received in the light receiving region of the light receiving portion is determined. It is possible to detect defective parts of the test object from the output signal. It is characterized in.

Further, according to the transparent body inspection method of the present invention,
Prior to projecting a linear beam onto the test object,
This beam can be waveform-shaped so that the projection area of the beam in the irradiation width direction of the object is narrowed.

In order to achieve the above object, a light source that emits inspection light toward an object to be inspected, and an inspection light from the light source is projected onto the object to be inspected in the width direction of the object to be inspected. A first beam shaping means for shaping a linear beam having a narrow length direction orthogonal to and an inspection light that is transmitted or specularly reflected from a normal portion of the inspection object among the inspection light incident on the object. A light-shielding area shielded by a light-shielding member for incidence / light reception, and inspection light refracted or scattered at the defect portion of the test object are incident / received, and a signal corresponding to the amount or intensity of the inspection light incident / received is generated. A light receiving portion having a light receiving area provided excluding a light shielding area for outputting, and a signal processing portion for inputting an output signal from the light receiving portion and detecting a defective portion of the test object. There is.

In the above structure, the inspection light formed into a linear beam having a narrow length direction orthogonal to the width direction of the test object is projected by the beam in the length direction of the test object. Second beam shaping means for converging the light so as to narrow the light area, and third beam shaping means for converging the inspection light so as to narrow the light projection area of the beam in the width direction orthogonal to the length direction of the test object. And may be provided.

In the above structure, the light source and the first
The beam shaping means may be composed of a laser diode module in which a laser diode and a lens are integrally combined. According to such a configuration, repair, replacement of parts,
Inspections can be easily performed.

Further, in the above-mentioned structure, the waveform shaping means is configured to converge the beam so that the light projection area in the irradiation width direction of the object on which the linear beam is projected is narrowed. be able to. Further, the light receiving section may be composed of a semiconductor photodetector.

Further, in the above arrangement, cylindrical lenses are used for the first beam shaping means, the second beam shaping means and the third beam shaping means, respectively, and both end portions of the cylindrical lens on the side of the third beam shaping means are used. It is preferable to provide a light-shielding member. With this configuration, the emission width of the beam can be regulated, and at the same time, generation of ghost light due to reflection inside the lens can be suppressed.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. Figure 1
Shows an inspection device for a test object according to the present invention,
This inspection device for an inspection object includes a light source 1, a first lens 11 which is a first beam shaping unit, a second lens 2 which is a second beam shaping unit, and a third lens 3 which is a third beam shaping unit.
The light receiving unit 4 and the signal processing unit 5 are provided, and in this embodiment, a defective portion is optically detected with respect to a continuously transferred transparent or semitransparent film 6 or the like. Is configured to.

The light source 1 emits inspection light for detecting a defective portion of the object 6 to be inspected. In this embodiment, a semiconductor laser (LD) is used, for example, a wavelength of 680.
Visible light of about nm is emitted as a diffused beam. The light source 1 is arranged such that the optical axis thereof is parallel to the Y direction perpendicular to the inspection (XZ) plane of the object 6 to be inspected. In this embodiment, from the viewpoint of life, cost, etc. Although the semiconductor laser is used, other than this, for example, a He-Ne laser or the like may be used.

Further, in order to perform waveform shaping as a laser beam with a narrow projection width (W) of the inspection light emitted from the light source 1, the two optical elements of the light source 1 and the first lens 11 are integrated. , LDM-6820 manufactured by Neoarc Co., Ltd.
If H or the like is used, it can be realized at a low cost and with a long life.

The second lens 2 emits a beam-like inspection light α emitted from the first lens 11 in a diffused state in a linear shape having a length (Z) direction orthogonal to the width (X) direction of the object 6 to be inspected. The beam is shaped into a beam and is projected toward the inspection region S of the object 6 to be inspected. By significantly narrowing the scanning range in a line shape (for example, as compared with slit light having a relatively wide scanning width). ) It is configured so that inspection accuracy can be improved. In the second lens 2 of this embodiment, a light component (longitudinal component) of the inspection light that is going to diffuse in the length (Z) direction of the test object 6 is shaped and converged into a substantially linear shape, and thus is approximately half. A cylindrical lens formed in a cylindrical shape is used, and the cylindrical lens is arranged so that the generatrix of the circumferential surface is parallel to the X axis.

A cylindrical lens is used as the third lens 3, and the second lens 2 has a generatrix (Z) direction on the circumferential surface.
Are arranged so as to be orthogonal to the generatrix (X) direction forming the circumferential surface of the. Particularly, in the third lens 3, the inspection light of the light component (lateral component) of the inspection light α which is to be diffused in the width (X) direction of the object 6 is converged to an appropriate projection angle (θ). Thereby, the light projection width (W) to the inspection portion S which is the inspection region of the inspection object 6 is narrowed to a desired width (100 mm in this embodiment), for example, with a specific narrow width where a defective portion is likely to occur. It is also possible to efficiently inspect the defective portion of the inspected portion S.

In particular, as shown in FIG. 1, the third lens 3 has an incident surface 3A having a curved surface on which the inspection light α is incident.
As shown in FIG. 2 (A), light shielding members 31 having a required length (L) are attached to the left and right (X) end portions of the same along the curved surface 3A. The light blocking member 31 regulates the emission width (see FIG. 1) when the inspection light α1 is emitted from the emission surface 3B, and the inspection light α1 emitted from the emission surface 3B and transmitted through the normal portion of the test object 6. To prevent the incident light from entering a portion other than a light-shielding region (corresponding to the light-shielding member 41) described later of the light-receiving portion 4. For example, a black tape or a dielectric multilayer film that absorbs the incident inspection light α1 is formed. You may comprise by the antireflection film of a structure.

That is, as shown in FIG. 2B, the light shielding member 31 emits the inspection light α2 which has undergone multiple scattering at least twice at the left and right end portions inside the second lens 3 and is on the emitting surface 3B. From the outside to a predetermined exit angle β1 and another exit angle β2
To prevent directional emission. As a result, the inspection light α
However, depending on the conditions, for example, even though the light enters the normal portion of the object 6 to be inspected, it is emitted in another direction as the inspection light α2, and is emitted to a light receiving area other than the detection surface 41 (light shielding area) of the light receiving unit 4 described later. When it is incident, it causes false detection as a defect portion D,
It is possible to prevent such troubles from occurring.

The light receiving section 4 is emitted from the light source 1, passes through the first lens 11, the second lens 2 and the third lens 3 and is beam-formed into a line beam shape (or a slit beam shape). The inspection light transmitted through the inspection unit S (see FIG. 1) is incident and received. As shown in FIG. 3A, the inspection light transmitted through the normal portion of the inspection object 6 is incident and received. Light-shielding area 4A and defective portion D such as wrinkles of the inspection object 6
(See FIG. 1) and a light receiving region 4B on which the inspection light refracted or scattered is incident and received. Therefore, in the light receiving section 4 of this embodiment, the light shielding area 4A in the central portion is slightly wider than the size of the inspection light α in the vertical (Z) direction, or can cover a size of some fluctuation. A light blocking member 41 having a size (H) is provided.

Then, the light receiving section 4 outputs a signal of a voltage level (or current value) corresponding to a change in the amount of incident light (or incident intensity) received by the light receiving section 4, whereby the defective portion D of the test object 6 is output. Is configured to detect. A semiconductor photodetector, for example, an appropriate photoelectric conversion element or the like is used for the light receiving unit 4 of this embodiment, but in order to receive the inspection light that is refracted or scattered at the defect portion D, You need something as large as possible. From this point of view, a photomultiplier tube may be used as the light receiving section 4, but since this photomultiplier tube is expensive and has a short life, a large area photodiode, for example, a PIN photodiode (S3584-08) manufactured by Hamamatsu Photonics KK is preferable. .

Therefore, when the inspection object 6 has a defective portion D such as wrinkles, the defective portion D is the inspection portion S.
At the moment of reaching, the line-shaped (or slit-shaped) beam that is the inspection light is refracted or scattered and the optical path is changed.
As shown in (B), the light-shielding member 41 protrudes from the light-shielding region to receive light in the light-receiving region 4B. As the light blocking member 41, a black tape that absorbs the inspection light α1 or an appropriate absorption film can be used.

The signal processing section 5 detects a defective portion of the test object 6 based on the signal output from the light receiving section 4. In this embodiment, the binarization circuit 51 and the output circuit 5 are used.
2 and. The binarization circuit 51 determines that there is a defective portion when the output (light receiving) signal level from the light receiving unit 4 becomes equal to or higher than a preset voltage value (threshold value), and the input is the output of the light receiving unit 4. It is connected. That is, when the defective portion D exists, this means that the light shielding member 4 of the light receiving portion 4 is
Since the inspection light α1 is incident on and received by the light receiving region 4B that extends out of the area 1, the output voltage level of the light receiving unit 4 rises as compared with the case where the normal portion without the defect portion D is transmitted, and the defect portion exceeds the threshold value. It is judged that there is D.

The output circuit 52 is for taking out the information obtained by processing by the binarization circuit 51 to the outside of the signal processing unit 5, and if necessary, for example, over the entire length of the test object 6. The inspection result of the defective portion D can be printed by a printer or the defective portion D can be continuously displayed on the display, and the input is connected to the output of the binarizing circuit 51.

Next, the operation of this embodiment will be described. The inspection light emitted from the light source 1 becomes a beam that spreads in the X direction by the first lens 11, and is then substantially parallel to the width (X) direction of the test object 6 and narrows in the length (Z) direction by the second lens 2. It is formed into a wavy line. Further, the third lens 3 is shaped so that the spread in the width (X) direction of the test object is narrowed (in this embodiment, half the width of the test object 6),
It becomes a linear beam with a narrowed tip and is projected onto the object 6 and the light receiving section 4.

On the other hand, the object 6 is continuously (in the direction perpendicular to the wavefront of the inspection light α1) so as to cross the optical path of the inspection light α1 between the third lens 3 and the light receiving portion 4. The inspection light α1 is constantly projected onto the inspection (XZ) surface of the object 6 to be inspected. For this reason, in this embodiment, the structure to be inspected S
It is possible to continuously scan a very thin region of the object 6 to be inspected by the inspection light. That is, it is possible to continuously detect the defective portion D with high accuracy.

As described above, when the inspection object α is the normal portion of the inspection object S to which the inspection light α1 is projected, the inspection light α1 is incident on the light shielding area 4A of the light receiving portion 4 without protruding from the light shielding member 41. . As a result, the inspection light α1 that enters and receives the light-shielding region 4A has a small amount of received light, and thus the output signal from the light-receiving unit 4, that is, the voltage level is also low. Therefore, in the binarization circuit 51 of the signal processing unit 5, a voltage equal to or lower than the threshold is input from the light receiving unit 4, it is determined that there is no defective portion D, and the output signal is output to the output circuit 52. Thus, for example, when a printer is connected to the output circuit 52, the inspection data is printed as if there is no defective portion in this portion.

On the other hand, when the inspection object 6 has a defective portion D, when the defective portion D reaches the inspection portion S, the inspection light α1 is refracted or scattered at the defective portion D, and the inspection light α1 is inspected. The optical path through which light travels changes. Therefore, the inspection light α1
The light-receiving position of the light-receiving unit 4 is shifted from the light-shielding region 4A provided with the light-shielding member 41, and the light is received and received by the light-receiving region 4B of the light-receiving unit 4. For this reason, the amount of light received by the light receiving unit 2 is larger than that in the normal portion, and the output signal from the light receiving unit 4, that is, the voltage level and the like is correspondingly increased. Therefore, in the binarization circuit 51, a voltage exceeding the threshold is applied to the light receiving unit 4
Is input, and it is determined that there is a defective portion D, and an output signal is output to the output circuit 52. This allows
The inspection data is printed assuming that there is a defective portion D in this portion.

In this embodiment, the line-shaped beam is converged by the third lens 3 so as to suppress the spread of the line-shaped beam.
If the width is small, the inspection may be performed over the entire width of the inspection object 6. Conversely, the beam projection width (W)
When the width of the inspection object 6 is wider than that of the inspection object, the inspection light may be projected only to the region where the defective portion frequently occurs, or the inspection devices having the same configuration are arranged in parallel to each other. Inspection over the entire width of 6 is also possible.

Therefore, according to this embodiment, the test object 6
Is configured to be continuously transferred on a production line or the like, and a dedicated scanning mechanism is not particularly required when irradiating the object 6 to be inspected. Therefore, it is possible to manufacture with a simple configuration and at low cost. Will be able to. Further, according to this embodiment, the light receiving unit does not need a complicated and expensive component such as an image pickup camera, and can be configured by a simple photodiode, a light receiving sensor, or the like, so that the cost can be further reduced. be able to. Further, in this embodiment, since the light shielding member 31 is provided on the second lens 3 and the generation of ghost light due to the scattering inside the second lens 3 can be suppressed, the detection sensitivity can be improved. Although the long sheet material that is continuously transferred is used as the test object of the present invention, a sheet material (cut sheet) or the like may be used instead.

Further, the inspection apparatus of this embodiment is configured to detect a defective portion of a transparent or anti-transparent test object. For example, the reflectance having a defective portion such as a wrinkle or a scratch on the surface portion. It is also applicable as an inspection device for detecting a defective portion of a high-sheet-like object to be inspected. That is, in this case, the light source and the first beam forming unit (the second beam forming unit to the third beam forming unit, if necessary) are used to cause the inspection light to enter the surface at a constant incident angle ( For example, it is arranged so as to be incident at δ). On the other hand, when the inspection light from the light source is reflected by the normal part of the test object, the light receiving part is arranged so that the light receiving area is arranged at the position where the light is specularly reflected at the reflection point and returns. It may be arranged so as to be inclined at the same angle (δ) in the space on the side (in the same space as the light source side unlike the previous embodiment).

[0034]

As described above, according to the present invention, the scanning width in the longitudinal direction of the test object is set to a line.
On the other hand, the light receiving part also shields the area where the linear beam that has passed through the normal part is incident according to the width of the beam, and finely detects defects in the test object. Will be able to. Therefore, it is convenient because it does not require a complicated scanning mechanism, an expensive camera, or the like, in other words, the defect structure can be accurately detected with a simple structure and at low cost.

Further, according to the present invention, in particular, the inspection light is configured so that the projection width of the beam for projecting / irradiating the object by the third beam converging means can be narrowed, and the inspection width The beam can be projected with a narrower projection width for an object with a relatively narrower width, so it is reasonably defective, especially for an object with a relatively narrow inspection width. You will be able to inspect parts.

[Brief description of drawings]

FIG. 1 is a perspective view showing a configuration of an inspection device for a test object according to the present invention.

FIG. 2A is an enlarged optical path diagram showing a main part of a third lens in the inspection device for an object of the present invention, and FIG. 2B is an optical path diagram showing a defect in the case where a light shielding member is not provided. .

3A and 3B show a light receiving portion of the inspection apparatus for an object to be inspected according to the present invention, FIG. 3A is an explanatory view showing a light receiving state when a normal surface of the object to be inspected is irradiated, and FIG. It is explanatory drawing which shows the light receiving state at the time of irradiating to.

[Explanation of symbols]

Reference Signs List 1 light source 11 first lens (cylindrical lens; first beam shaping means) 2 second lens (cylindrical lens; second beam shaping means) 3 third lens (cylindrical lens; third beam shaping means) 31 light blocking member 4 light receiving section 4A Light-shielding area 4B Light-receiving area 41 Light-shielding member 5 Signal processing unit 51 Binarization circuit 52 Output circuit α Inspection light θ Projection angle D Defective portion S Inspected portion W Projected width X Width direction of inspection object Z Inspection object Length direction (transfer direction)

Claims (7)

[Claims] 1. An inspection light from a light source that is emitted toward an object to be inspected is shaped into a linear beam having a narrow length direction orthogonal to the width direction of the object to be inspected. Of the inspection light that is projected onto the inspection object as inspection light and is incident on the inspection object, only the inspection light that transmits or specularly reflects the normal portion of the inspection object is blocked by the light-shielding member. Of the inspection light incident on the object to be inspected and received, only the inspection light refracted or scattered at the defective portion of the object to be inspected is received without the light-shielding member of the light receiving section. A method for inspecting a test object, which is characterized by detecting a defective portion of the test object from an output signal according to a light amount or a light intensity of the test light received in the light receiving area of the light receiving unit. . 2. Prior to projecting a linear beam onto the test object, the beam is converged so as to narrow the projecting area of the beam in the width direction orthogonal to the length direction of the test object. The method for inspecting an object according to claim 1, wherein the inspection is performed. 3. A light source for emitting inspection light toward an object to be inspected, and a length direction orthogonal to a width direction of the object to be inspected when the inspection light from the light source is projected onto the object to be inspected. The first beam shaping means for shaping into a linear beam, and the light shielding member for injecting and receiving the inspection light that is transmitted or specularly reflected from the normal portion of the inspection object among the inspection light incident on the inspection object Provided except the shaded area and the shaded area where the inspection light refracted or scattered at the defect portion of the test object enters and receives and outputs a signal according to the light amount or the light intensity of the incident and received inspection light. An inspection apparatus for an object to be inspected, comprising: a light receiving section having a light receiving area; and a signal processing section for inputting an output signal from the light receiving section to detect a defective portion of the object to be inspected. 4. The light projection area of the beam in the length direction of the test object is narrowed by the inspection light shaped into a linear beam having a narrow length direction orthogonal to the width direction of the test object. And a third beam shaping unit that converges the inspection light so that the beam projection area of the beam in the width direction orthogonal to the length direction of the object is narrowed. The inspection device for an object according to claim 3, wherein 5. The object to be inspected according to claim 3, wherein the light source and at least the first beam shaping unit are constituted by a laser diode module in which a laser diode and a lens are integrally combined. Inspection device. 6. The inspection apparatus for an object to be inspected according to claim 3, wherein the light receiving section is composed of a semiconductor photodetector. 7. A cylindrical lens is used for each of the first beam shaping unit, the second beam shaping unit and the third beam shaping unit, and a light blocking member is provided at both ends of the cylindrical lens of the third beam shaping unit. Claim 3 or 4 characterized by the above.
The inspection device for the inspection object according to 1.