JP2873450B2 - Defect inspection device using light - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a defect inspection apparatus using light for inspecting a defect of a film sheet, a defect of a disk surface, and the like by using light. One-dimensional CCD camera receives light transmitted through or reflected from a film sheet by applying linear light such as a lamp, and runs the film sheet to detect changes in the transmitted light or reflected light. The present invention relates to a defect inspection device for detecting a defect.

[Prior Art] A defect inspection apparatus using light has been conventionally known. A conventional defect inspection apparatus irradiates a long linear light such as a fluorescent lamp to an inspection object such as a film sheet and measures the light transmitted through the inspection object with a one-dimensional CCD camera.

9 to 12 are diagrams showing an outline of a conventional defect inspection apparatus. FIGS. 9 and 10 show transmission type inspection apparatuses, and FIGS.
The figure shows a reflection type. In these figures, 1 is a linear light source, 2 is a film sheet to be inspected, 3
Is a light detecting means such as a one-dimensional CCD camera. That is, the defect is detected by detecting the light transmitted through the film sheet or reflected by the film sheet with the light from the light source.

[Problems to be Solved by the Invention] In the conventional defect inspection apparatus as described above, since a light source uses a horizontally long linear light source such as a fluorescent lamp, it is irradiated with light from all angles in the horizontal direction. Therefore, particularly when the defect of the inspection object is perpendicular to the horizontal direction of the light source, for example, in the case of a vertical scratch, the transmitted light or reflected light incident on the one-dimensional CCD camera is light from a wide range of angles of the light source, It is difficult to obtain an optical signal representing the feature of the defect, and it is difficult to detect the defect.

In order to solve such a drawback, a method has been conventionally known in which a light source is replaced with a point light source and a convex lens is combined with the light source so that all light from the light source is directed to a one-dimensional CCD camera. But this method
For example, when the size of the object to be inspected is large, such as a film sheet, a large lens and a light source with strong power are required, so that it is not practical and cannot be adopted.

An object of the present invention is to provide a defect inspection apparatus that can detect a defect with higher accuracy by having a configuration that can easily convert light from a light source into an approximate parallel light beam.

[Means for Solving the Problems] In order to solve the above-mentioned problems, a defect inspection apparatus of the present invention applies light from a linear light source to an object to be inspected, and transmits transmitted light or reflected light thereof to a one-dimensional CCD camera. An apparatus for inspecting defects such as scratches on an inspection object based on a change in the amount of received light, wherein the CCD array of the one-dimensional CCD camera is arranged between the linear light source and the inspection object. A slit member composed of a number of slit plates arranged in parallel in a direction perpendicular to the direction is provided.

According to the defect inspection apparatus of the present invention, the light from the linear light source is converted into a light beam similar to a parallel light beam by the slit plate and hits the inspection object, and transmitted light or reflected light is CC.
Received by D camera. Therefore, the scattered light obliquely is blocked by the slit plate, and the inspection can be performed without being affected by the light.

Embodiment Next, an embodiment of the defect inspection apparatus of the present invention will be described. 1 and 2 are a front view and a side view, respectively, of a transmission type apparatus according to an embodiment of the defect inspection apparatus of the present invention. In these figures, 1 is a linear light source such as a fluorescent lamp, 2 is a film sheet to be inspected, 3 is a one-dimensional CCD camera, 4 is a light source disposed between the light source 1 and the film sheet. A slit member provided with a number of slit plates 4a in a direction perpendicular to the length direction, and has a structure as shown in FIG. The light emitted from the light source 1 is transmitted to the slit plate of the slit member 4.
It is set so that only the light passing between 4a enters the one-dimensional CCD camera. That is, as shown in the figure, the interval between the slit plates is set to the light source side (incident side) so that the light beams passing between the slit plates 4a are substantially parallel to each other and all these light beams are directed toward the one-dimensional CCD camera. ) Is slightly larger than on the inspection object side (injection side).

According to the apparatus of this embodiment, light emitted from the light source 1 and passing between the slit plates 4a of the slit member 4 and passing through the film sheet to be inspected enters the one-dimensional CCD camera. Here, the light incident on the one-dimensional CCD camera is only a light flux almost parallel to each other perpendicular to the length direction of the light source 1 passing through a number of slits, so that there is no oblique disturbance light, and the noise-free accuracy is high. Good detection becomes possible.

Each slit plate 4a of the slit member 4 used in this embodiment
It is preferable that the thickness be as thin as possible within a range not to impair the mechanical strength, and that the slit width and the slit interval be as small as possible and as long as possible in the optical path direction, because the accuracy is improved. However, if the length is too long in the direction of the optical path, the amount of light from the light source decreases, resulting in a decrease in sensitivity. Therefore, it is desirable that the above-mentioned length is set to an appropriate length according to the state of the inspection object and its defect. Further, the distance between the slit member 4 and the inspection object 2 is preferably as small as possible so as not to be within the depth of focus of the one-dimensional CCD camera 3. However, if it is too small and enters the depth of focus, the shadow of the slit plate 4a becomes noise, which is not preferable.

3 and 4 are a front view and a side view of a reflective embodiment of the device of the present invention. As shown in the drawing, the light source 1 and the slit member 4 are different from the transmission type in that the light source 1 and the slit member 4 are arranged on the same side as the one-dimensional CCD camera 3 with respect to the inspection object. In the case of the reflection type, light from the light source 1 passes through each slit 4a of the slit member 4, is reflected by the inspection object 2, and is then detected by the one-dimensional CCD camera. Other functions and measurement principles are substantially the same as those of the transmission type.

FIG. 5 is a diagram showing an outline of a transmission type apparatus including an image processing system and the like of the present invention. As described above, the light from the light source 1 passes between the slit plates 4a, further passes through the inspection object 2, and is received by the one-dimensional CCD camera. In the one-dimensional CCD camera 3, an output signal from each CCD element generated by a light quantity difference according to the presence or absence of a defect of the inspection object is input to the signal processing device 5 as a one-dimensional video signal. The image processing is carried out to determine the defect, and the result is output to the CRT display 7 and the printer 8.

FIG. 6 shows that each slit plate 4a of the slit member 4 is
Are arranged vertically with respect to the inspection object 2 and one-dimensional
A condensing lens 9 is provided between the camera and the CCD camera 3.
FIG. 9 is a view showing another embodiment in which light is condensed on a CCD camera 3.

In this embodiment, since the width of the inspection object 2 and the installation width of the slit plate 4 are the same, as shown in the drawing, the one-dimensional CCD is used.
When the number of the cameras 3 is two or more, the inspection line of the inspection object 2 can be aligned on the same line.

[Effects of the Invention] According to the defect inspection apparatus of the present invention, light irradiated on a defect portion such as a scratch of an inspection object is a one-dimensional CCD from a light source.
Since only the light goes straight to each element, the influence of disturbance light can be removed, thereby improving the S / N ratio, and a defect that could not be detected due to disturbance light with the conventional device can be detected.

[Brief description of the drawings]

1 is a front view of a transmission type embodiment of the present invention, FIG. 2 is a side view of the embodiment, FIG. 3 is a front view of a reflection type embodiment, and FIG. 4 is a side view of the embodiment. FIG. 5 is a diagram showing an outline of a configuration including an image processing system of a transmission type embodiment, FIG. 6 is a front view of another embodiment, FIG. 7 is a side view of the embodiment, and FIG. FIG. 9 is a perspective view showing an example of a slit member used in the apparatus of the present invention. FIG. 9 is a front view of a conventional transmission type defect inspection apparatus.
FIG. 10 is a side view of the conventional example, FIG. 11 is a front view of a conventional reflection type defect inspection apparatus, and FIG. 12 is a side view of the conventional example. 1 ... linear light source 2 ... inspection object 3 ... one-dimensional CCD
Camera, 4 ... Slit member, 4a ... Slit plate

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G01N 21/84-21/90

Claims (2)

(57) [Claims] 1. A defect inspection apparatus which irradiates light from a linear light source onto an inspection object, captures transmitted light or reflected light of the inspection object with a one-dimensional CCD camera, and inspects a defect of the inspection object based on a change in the amount of light. The light flux passing between the slit plates, comprising a number of slit plates arranged substantially parallel to a direction orthogonal to the arrangement direction of the CCDs of the one-dimensional CCD camera between the linear light source and the inspection object, the light flux passing through the one-dimensional A defect inspection apparatus using light, wherein a slit member is disposed such that the distance between the slit plates is larger on the light source side than on the inspection object side so as to be directed toward the CCD camera. 2. A defect inspection apparatus which irradiates light from a linear light source onto an object to be inspected, detects transmitted light or reflected light by a one-dimensional CCD camera, and inspects defects of the object to be inspected based on a change in the amount of light. A slit member composed of a number of slit plates arranged in parallel in a direction orthogonal to the CCD arrangement direction of the one-dimensional CCD camera is arranged between the linear light source and the inspection object, and passes between the slit plates. The one-dimensional CCD
One-dimensional CC of the slit member so as to face the camera direction
A defect inspection device using light, characterized in that a condenser lens is arranged on the D camera side.