JPH07270325A - Defect inspector - Google Patents

Abstract

PURPOSE:To provide a defect inspector wherein a defect of white color or almost white color or another defect in response to changes of a polarized light state produced on an object to be inspected can be detected. CONSTITUTION:A transparent or almost transparent object to be inspected 3 transmits the light emitted from a light source 1, its transmission light is received by a light receiving means 5, and a filter 2 for regulating wavelength of light received by the light receiving means 5 or a pair of polarized light plates 6, 7 are provided on a part of a light route leading to the light receiving means 5 from the light source 1 of the defect inspector, which performs defect inspection of the object to be inspected.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a defect inspection device for inspecting a defect of a test object by receiving transmitted light from a transparent or substantially transparent test object by a light receiving means.

[0002]

2. Description of the Related Art Conventionally, light emitted from a light source such as a laser is transmitted through a transparent or substantially transparent test object, and the transmitted light is received by a photoelectric conversion element, and the received light changes from the received light amount. A defect detection device for detecting a defect in an inspection object is known (see Japanese Patent Laid-Open No. 59-116038). In addition, by using white light such as a fluorescent lamp or a halogen lamp as a light source, the light emitted from the light source is transmitted to the test object, the transmitted light is photographed by a CCD camera, and the photographing result is visually observed. 2. Description of the Related Art A defect detection device that detects a defect in a test object is known.

[0003]

However, in the conventional defect inspection apparatus, when the defect of the object to be inspected is white or substantially white, the change of the transmitted light is weak, so that the defective portion and the normal portion can be distinguished from each other. There was a problem that it was difficult. Furthermore, it has been difficult for the conventional defect inspection apparatus to detect a defect caused by a change in the polarization state of the test object.

Therefore, an object of the present invention is to provide a defect detecting apparatus capable of detecting a white or substantially white defect. Another object of the present invention is to provide a defect inspection apparatus capable of detecting a defect caused by a change in the polarization state of a test object.

[0005]

In order to solve the above-mentioned problems, the invention as set forth in claim 1 transmits light emitted from a light source to a transparent or substantially transparent test object and transmits the light. A defect inspecting device for receiving light by a light receiving means to inspect an object to be inspected, and a filter for adjusting a wavelength of light received by the light receiving means in a part of an optical path from the light source to the light receiving means. Is provided.

Further, in order to solve the above-mentioned problems, the invention according to claim 2 transmits light emitted from a light source to a transparent or substantially transparent test object and receives the transmitted light. Is a defect inspection device for inspecting an object to be inspected for defects by providing a pair of polarizing plates in a part of an optical path from the light source to the light receiving means, and configuring the polarizing plate pair. The light absorption directions of the respective polarizing plates are parallel to each other.

[0007]

According to the invention described in claim 1, since a filter for adjusting the wavelength of the light received by the light receiving means is provided in a part of the optical path, a defect detecting apparatus capable of detecting a white or substantially white defect. Can be provided. In the invention according to claim 2, a pair of polarizing plates is provided in a part of the optical path, and
Since the light absorption directions of the respective polarizing plates forming the pair of polarizing plates are parallel to each other, it is possible to detect a defect due to a change in the polarization state generated in the test object.

[0008]

EXAMPLES The present invention will be described below based on examples.
FIG. 1 is a configuration diagram showing a first embodiment of the present invention.
In this embodiment, as the test object 3, a semitransparent substrate coated with a dye after being molded with a resin is used. Further, for the purpose of detecting white dot-like defects that may occur when a dye is applied to a semi-transparent substrate and color unevenness that may occur due to defective dye application, the defects of this example The description will be made assuming that a detection device is used.

In FIG. 1, reference numeral 1 is a light source such as a fluorescent lamp or a halogen lamp. The light emitted from the light source 1 passes through the interference filter 2 and reaches the test object 3. The filter 2 has a function of adjusting the wavelength of light incident on the test object 3. Since the inspection object 3 is transparent or translucent, it is difficult to detect white or substantially white defects. Here, in order to easily detect the white or substantially white defect, the wavelength of the light incident on the test object 3 may be set to a wavelength at which the test object 3 has a high degree of absorption. If the wavelength of the light incident on the inspection object 3 is a wavelength at which the inspection object 3 has a high degree of absorption, the light radiated to the normal portion (the portion having no defect) is absorbed and finally output in black. This is because the contrast between the white or substantially white defect portion and the defect portion is improved and detection becomes easy. On the other hand, when light with too high absorptivity is emitted, the light irradiated to the normal part is absorbed and output as black, which makes it difficult to distinguish the normal part from the black defect, and the black defect cannot be detected. It will be difficult. Therefore, the filter 2 can detect both a white defect and a black defect in consideration of the light transmittance, color, wavelength of light that is easily absorbed, or the color of a defect desired to be detected, of the test object 3. As described above, the wavelength of the light incident on the DUT 3 is appropriately adjusted.

The light passing through the filter 2 is received by the CCD camera 5 as a light receiving means via the lens 4. C
The signal received by the CD camera 5 is then image-processed so that defects can be found more easily. In the above-mentioned apparatus, when a defect in the transmittance of the dye such as color unevenness is detected, it is possible to easily detect the defect due to the difference in the amount of received light if a quality judgment criterion is provided according to the wavelength. It will be possible.

Next, a second embodiment of the present invention will be described. FIG. 2 is a block diagram showing a second embodiment of the present invention. In the first embodiment, the filter 2 is provided in the optical path from the light source 1 to the test object 3, but in the second embodiment, the filter 2 is provided in the optical path where light passes through the test object 3 and reaches the lens 4. Is provided.

Next, a third embodiment of the present invention will be described. FIG. 3 is a block diagram showing a third embodiment of the present invention. In this embodiment, in addition to the configuration of the first embodiment, a pair of polarizing plates are provided for the optical path from the filter 2 to the test object 3 and the optical path from the test object 3 to the lens 4, respectively. A plate 6 and a polarizing plate 7 are provided. Here, the light transmission directions of the polarizing plates 6 and 7 are parallel to each other. By providing the polarizing plate 6 and the polarizing plate 7, in addition to the defects that can be detected in the first embodiment, the defects due to the change in the polarization state that cannot be detected in the first embodiment also reduce the amount of light received at the defective portion. It is also possible to detect by using

Next, a fourth embodiment of the present invention will be described. FIG. 4 is a block diagram showing the fourth embodiment of the present invention. In the third embodiment, the filter 2 includes the light source 1 to the polarizing plate 6
The filter 2 is provided in the optical path from the polarizing plate 7 to the lens 4 in this embodiment.

[0014]

According to the invention described in claim 1, since a filter for adjusting the wavelength of the light received by the light receiving means is provided in a part of the optical path, it is possible to detect a white or substantially white defect. A detection device can be provided. According to the second aspect of the present invention, a pair of polarizing plates is provided in a part of the optical path, and the light absorbing directions of the polarizing plates forming the pair of polarizing plates are parallel to each other. It is also possible to detect a defect due to a change in the polarization state that has occurred in (1).

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a first embodiment of the present invention.

FIG. 2 is a configuration diagram showing a second embodiment of the present invention.

FIG. 3 is a configuration diagram showing a third embodiment of the present invention.

FIG. 4 is a configuration diagram showing a fourth embodiment of the present invention.

[Explanation of symbols]

 1 Light Source 2 Filter 3 Test Object 4 Lens 5 CCD Camera 6 Polarizing Plate 7 Polarizing Plate

Claims (2)

[Claims] 1. A defect inspection apparatus for transmitting light emitted from a light source to a transparent or substantially transparent inspection object and receiving the transmitted light by a light receiving means to inspect the inspection object for defects. And a filter for adjusting the wavelength of the light received by the light receiving means is provided in a part of the optical path from the light source to the light receiving means. 2. A defect inspection apparatus for transmitting light emitted from a light source to a transparent or substantially transparent inspection object and receiving the transmitted light by a light receiving means to inspect the inspection object for defects. A pair of polarizing plates is provided in a part of the optical path from the light source to the light receiving means, and the light absorbing directions of the polarizing plates forming the pair of polarizing plates are parallel to each other. Defect inspection equipment.