JPH04191645A - Inspecting apparatus - Google Patents

Abstract

PURPOSE:To detects accurately defects differing in color components by a method wherein a synthesized light having a spectral radiation characteristic of detecting the defects or patterns with a prescribed sensitivity is emitted uniformly in an image-sensing range of an image sensor. CONSTITUTION:Lights of light sources 3a and 3b are made to enter incident parts 5a and 6a of optical fiber transmission units 4. The incident light is applied in an image-sensing range 8a of an image sensor 8 on a substance 6 to be inspected. An emission part 7 of the optical fiber transmission units 4 corresponds to each sensor element of the image sensor 8 and emits a synthesized light of the light from each of the light sources 3a and 3b by an optical fiber. Subsequently, a light from the image-sensing range 8a is sensed by the image sensor 8 and a sensed-light signal thereof is sent to a defect processing unit. According to this constitution, defects or patterns being different in color components in the substance can be detected with a prescribed sensitivity.

Description

[Detailed description of the invention] [Industrial application field]

The present invention relates to an inspection device for detecting defects with different color components, such as defects such as printing errors, oil stains, and other deposits that occur in color-printed manuscripts such as catalogs.

[Conventional technology]

For color-printed documents such as catalogs, there is a need for an inspection device that can accurately detect defects with different color components, such as printing errors, oil stains, and other deposits. The simplest possible inspection device that can meet this requirement is, for example, to provide an imaging system corresponding to the color component of the defect and to sense the object to be inspected. However, this inspection device requires an optical system that separates the colors and a sensor that separately senses each color-separated light, making it extremely complicated. Therefore, an inspection device that can inspect defects in a wide range of color components and has a simple configuration should consist of a sensor and a light source as a set, increase the brightness of the light source as much as possible on the light source side, and insert a filter to increase the spectral emissivity. There was something uniform about it.

[Problem to be solved by the invention]

However, in the above-mentioned inspection equipment, the spectral radiation characteristics of the light source are quite biased and it is difficult to correct a wide range with a filter, and the sensor itself also has spectral sensitivity characteristics, so it is difficult to correct a wide range of colors. It was difficult to test the ingredients.

[Means to solve the problem]

The present invention aims to solve the above problems and consists of the configuration shown below. That is, the present invention provides a light source device constituted by a light source group consisting of a plurality of light sources and whose combined emitted light has a spectral radiation characteristic expressed by equation (1); Characteristic =
A/B (1) However, A is the reflectance or transmittance of the defect, and B is the spectral sensitivity of the image sensor. It is composed of a plurality of optical fibers, and includes an entrance portion formed by dividing one end of the optical fiber and converging the other end and arranging it facing each light source of the light source device, and an entrance portion of each optical fiber. an optical fiber transmission unit, the other end of which is arranged to form an output unit configured to focus optical fibers from each light source and irradiate combined output light onto each sensor element of the image sensor; and the optical fiber transmission unit. It is characterized by comprising an image sensor that receives reflected light or transmitted light from the object to be inspected using light from the emission section.

[Effect]

The inspection device of the present invention has the following functions. First, in the inspection apparatus of the present invention, the light source device is composed of a plurality of light sources, and when the light emitted from these light sources is combined, it is possible to easily detect patterns with different color components generated on the object to be inspected. . For example, a case will be explained in which the defect and its pattern include all color components and it is required that spectral emissivity x spectral sensitivity = constant. Here, the spectral sensitivity of the image sensor is in the wavelength range of 400 to 700 nm as shown in Figure 3 (a).
Suppose that it has the characteristics shown in . When using an image sensor having the spectral sensitivity shown in Figure 3(a), it is necessary to have the spectral radiation characteristics shown in Figure 3(b) in order to inspect defects or patterns with different color components occurring on the object to be inspected. A light source that emits light is required. Normally, one searches for a light source with such spectral radiation characteristics and uses one that matches this.
− It is difficult to find a light source that matches the pre-convenience;
Furthermore, if the purpose of this inspection is to accurately detect defects with different color components, it is almost impossible to achieve this with a single light source. Therefore, in the present invention, a plurality of light sources generate light having the spectral radiation characteristics shown in FIG. 3(b). If the same figure (C)
Assuming that there is a light source having the spectral radiation characteristics shown in FIG. 12(d), the light combined from these two light sources becomes light having the spectral radiation characteristics shown in FIG. 14(b). This means (
1) The light has the spectral radiation characteristics shown in the formula. Further, in the present invention, the light having the above-mentioned spectral radiation characteristics is
An optical fiber transmission section with a plurality of optical fibers is used to uniformly illuminate the imaging range of the image sensor. That is, this optical fiber transmission section receives light from an input section formed by dividing light from each light source of the light source device. At the output section of the optical fiber transmission section, the optical fiber that guides the light shown in FIG. 10C and the optical fiber that guides the light shown in FIG. In other words, each sensor element of the image sensor is irradiated with light having the spectral radiation characteristics shown in FIG. 2(b). This allows the image sensor to detect defects or patterns with different color components occurring on the inspection object with a constant sensitivity.

【Example】

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing an outline of the inspection device of the present invention. In the figure, the inspection device 1 uses a sheet-like object 9 printed in color on paper, film, etc. as an object to be inspected, and detects defects with different color components such as printing errors, oil stains, and other deposits that occur on the object. It is something to detect. This inspection device 1 is mainly composed of three components: a light source device 2, an optical fiber transmission section 4, and an image sensor 7. The light source device 2 includes two light sources 3a and 3b, and specifically, a metal halide lamp, a halogen lamp, a fluorescent lamp, or the like is used as the light source. However, this light source has the necessary spectral radiation characteristics. In addition, a filter may be inserted into the light source device so that the combined light has the spectral radiation characteristics shown in equation (1). Therefore, the light source device 2 outputs the combined light corresponding to the spectral sensitivity of the image sensor. The following configurations are adopted by combining light sources and filters to create composite light: ■Create composite light using only multiple light sources with different spectral radiation characteristics.■Create combined light using only multiple light sources with different spectral radiation characteristics. A filter is inserted into one or both of the light sources to create a composite light. ■A composite light is created by inserting a filter into one or both of the light sources having the same spectral radiation characteristics. It is formed by an optical fiber bundle 5.6 which is a bundle of optical fibers 1<.Optical fiber transmission section 4
One end of this optical fiber bundle 5.6 focuses the respective optical fibers to form an input 5a16b. In these incident parts 5a and 6b, light sources 3a s 3b
They are arranged so that they face each other so that they can receive the same amount of light. Further, the optical fiber transmission section 4 is configured such that the other ends of the optical fiber bundles 5.6 are gathered together to form a light emitting section 7, and the light is irradiated into the imaging range 8a of the image sensor 8 on the object 9 to be inspected. It is set as. Here, the arrangement of optical fibers in the output section 7 of the optical fiber transmission section 4 will be explained. FIG. 2 is an enlarged top view of the output section 7 and image sensor 8 of the optical fiber transmission section 4. As shown in FIG. In the figure, the light emitting section 7 uses a line-type image sensor 8, so the same lines are formed. In the output section 7, a shaded optical fiber 60a,
60b. . . . are optical fibers that guide light from the light source 3a, and optical fibers 50as50b+, . . . are optical fibers that guide light from the light source 3b.
An optical fiber that guides light from Further, the image sensor 8 is composed of a plurality of sensor elements including sensor elements 8a, . . . . The viewing range of one sensor element 8a of the image sensor 8 is irradiated with combined light from a total of four optical fibers: two optical fibers from the light source 3a and two optical fibers from the light source 3b. In this embodiment, the number of optical fibers corresponding to the sensor elements is four, but the number is not limited to this and any number may be used. In addition, the light source 3a
, 3b need not be the same, and may be changed depending on the brightness transmitted by the optical fiber zH. Although not shown, the image sensor 8 is connected to a defect processing section, which detects the presence or absence of defects based on the light reception signal from the image sensor 8, checks their type, number, etc., and reports the inspection results. Next, functions etc. of the inspection device of the present invention will be explained. From FIG. 1, the light from the light sources 3a and 3b of the light source device 2 is
The light is input to the input sections 5a and 6a of the optical fiber transmission section 4. Then, the output section 7 of the optical fiber transmission section 4 irradiates the light that has entered from the input sections 5a and 6a into the imaging range 8a of the image sensor 8 on the object to be inspected 9. Note that the output section 7 of the optical fiber transmission section 4 outputs combined light from each light source through the optical fibers, corresponding to each sensor element of the image sensor 8. The image sensor 8 receives light from the imaging range of the object to be inspected 9, and sends the light reception signal to the defect processing section. In this manner, when the defect processing section detects a defect based on the light reception signal, it checks the type, number, etc., and notifies the inspection result.

【effect】

As detailed above, according to the inspection device of the present invention, the combined light of the plurality of light sources that constitute the light source device has spectral radiation characteristics that allow detection of various defects or patterns with a constant sensitivity. In addition, the combined light is emitted uniformly to the imaging range of the image sensor at the output section of the optical fiber transmission section, making it possible to accurately detect defects with different color components, which is highly effective. .

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an apparatus showing one embodiment of the present invention, and FIG.
The figure is a top view of the output section of the fiber transmission section and the image sensor shown in FIG. 1, and FIG. 3 is a characteristic diagram showing the spectral sensitivity of the image sensor and the spectral radiation characteristics of the light source. 1... Inspection device 2... Light source device 3a, 3b... Light source 4... Optical fiber transmission section 5.6... Optical fiber bundle 5a, 6a... Input section 7... Output section "50 as 50 bs...Optical fibers 60a, 60b that guide the light from the light source 3b,...Optical fiber 8 that guides the light from the light source 3a...Image sensors 8a, 8b, 8c, -...Sensor element 9.・
・Object to be inspected ω Fig. 3 (a) Wavelength [nm] Fig. 3 (b) Wavelength [stop Fig. 3 < C) Wavelength [nm Fig. 3 < d)

Claims (2)

[Claims] (1) In an inspection device that uses an image sensor to inspect defects or patterns of different color components occurring on an object to be inspected, it consists of multiple light sources, and the combined emitted light from these light sources is expressed by equation (1). A light source device composed of a group of light sources having spectral radiation characteristics, and spectral radiation characteristics of combined emitted light = A/B (1) However, A is the reflectance or transmittance of the defect, and B is the spectral sensitivity of the image sensor. be. It is composed of a plurality of optical fibers, and includes an entrance portion formed by dividing one end of the optical fiber and converging the other end and arranging it facing each light source of the light source device, and an entrance portion of each optical fiber. an optical fiber transmission unit, the other end of which is arranged to form an output unit configured to focus optical fibers from each light source and irradiate combined output light onto each sensor element of the image sensor; and the optical fiber transmission unit. An inspection device comprising: an image sensor that receives reflected light or transmitted light from an object to be inspected using light from a light emitting section of the inspection device. (2) The inspection device according to claim 1, wherein the light source device is provided with a filter for correcting spectral radiation characteristics of the light emitted from the light source.