JPH046447A - Exposure apparatus and detecting apparatus - Google Patents

Abstract

PURPOSE:To irradiate a part to be exposed uniformly with light and to make it possible to improve detecting accuracy by providing a constitution wherein the central part of a first light diffusing filter is curved and formed to the side of a light source, the central part is separated from a second light diffusing filter, and the end parts are close to the second filter. CONSTITUTION:A first light diffusing filter DF1 is formed so that the central part is curved in the protruding pattern to the side of a light source (halogen lamp 13). The central part is separated from a second light diffusing filter DF2, and the end parts are close to the second filter. When the amount of the light which is emitted from the halogen lamp 13 on the first light diffusing filter DF1 is uniform, the amount of the light at a part (L1) which is close to the first light diffusing filter DF1 becomes large. The amount of the light at a part (L2) which is far from the DF1 becomes small. Therefore, when the part where the amount of the light to the second light diffusing filter DF2 is large is separated from the DF2 and the part where the amount of the light is small is made to approach, the intensity of the emitted ray become uniform, and layer 1 is uniformly irradiated.

Description

DETAILED DESCRIPTION OF THE INVENTION (A) Field of Industrial Application The present invention relates to an exposure apparatus and a detection apparatus using the exposure apparatus, and in particular, to an apparatus capable of uniformly illuminating an exposed area.

(b) Prior Art Conventionally, a device as shown in FIGS. 1 to 3 has been proposed as a device for detecting opaque foreign matter mixed in sheet-like dried seaweed (1). Note that FIG. 1 is a front view, FIG. 2 is a plan view, and FIG. 3 is a theoretical conceptual diagram.

In these figures, reference numeral 1 denotes a translucent sheet of dry seaweed as an object to be measured, which is formed to a predetermined size. The seaweed 1 is placed on two parallel belt conveyors 2.3 and conveyed from the right side to the left side in the figure at a speed of about 40 m/min. The belt conveyor 2.3 is divided into upstream conveyors 2a, 3a and downstream conveyors 2b, 3b, and a transparent plate 4 made of glass or the like is attached to each divided portion.

The rain upstream conveyor 2a, 3a and the downstream conveyor 2b
, 3b, above the transparent plate 4 provided at the dividing part,
A camera 11 is provided as a means for reading the light beam transmitted through the seaweed 1. A lens 12 is attached to the camera 11.

A /A rogen lamp 13 as a light source is provided below the belt conveyors 2a, 3a on the upstream side below the dividing portion, and a filter 14 is attached to the /A rogen lamp 13. and the halogen lamp 13
On the downstream side in the horizontal direction, directly below the transparent plate 4, there is seaweed l.
A reflecting mirror 15 extending in a direction perpendicular to the conveying direction of the seaweed 1 is provided, and a reflecting mirror 15 for converging the light beam reflected by the reflecting mirror 15 onto the irradiated part (the part through which the light beam is transmitted) on the back surface of the seaweed 1. , cylindrical convex lens 1
6 is provided.

Between the convex lens 16 and the transparent plate 4, there is a half extending in a direction parallel to the convex lens 16 in order to make the light beam from the halogen lamp 13 uniform in a direction perpendicular to the transport direction of the seaweed 1. A transparent milky white light diffusion filter DF is interposed.

Further, the halogen lamp 13 is connected to a stabilized power source 17. The camera 11 is connected to a camera controller, and the camera controller is connected to an oscilloscope, a CRT monitor system, etc. The mechanism section is equipped with a timing sensor (rotary encoder), a drive control circuit, and the like. Although not shown, the belt conveyor 2.3 is equipped with a defective product discharging device for sorting and discharging defective seaweed 1.

The reason why the camera 11 is provided above the middle part of both belt conveyors 2.3 is that the camera 11 is spaced apart from the seaweed 1 and the patterns of the two sheets of seaweed 1 on each belt conveyor 2.3 can be viewed at the same time. This is to allow the lens 12 to project and image the image onto the CCD. 23.23 is a conveyor roller.

The seaweed 1 transported by the upstream conveyors 2a and 3a is exposed from below by the halogen lamp 13 on the upper part of the transparent plate 4, and the transmitted light from the exposed area is captured by the camera 11. be read. The read light beam is converted into an electrical signal, and the signal is processed to detect foreign objects.

However, the foreign matter detected in this case is opaque, such as a metal piece, an opaque resin piece, or a piece of wood, and its brightness does not matter. That is, if opaque foreign matter is mixed into the seaweed 1, regardless of whether it is on the front or back or inside, the foreign matter will be read and detected by the camera 11.

As described above, the seaweed 1 in which foreign matter has been detected by the camera 11 is discharged to a predetermined location.

By the way, in the above-mentioned apparatus, the light emitting part (lens, 14) of the halogen lamp 13 has a circular shape. On the other hand, since the seaweed 1 is subjected to strip-shaped slit exposure in a direction perpendicular to the transport direction, the distance from the light source to the exposed area is shortest at the center and longest at the ends. Since the illuminance of the exposed area is inversely proportional to the square of the distance from the light source, the illuminance is highest at the center and gradually decreases toward the ends.

Therefore, the seaweed 1 cannot be uniformly exposed. This state will be explained with reference to FIG. In the example shown in FIG. 3, as mentioned above, a grain-colored anti-transparent light source extending in a direction parallel to the slit exposure direction (left-right direction in the figure) is placed between the light source (halogen lamp 13) and the seaweed 1. A light diffusion filter DF is interposed to detect opaque foreign matter A by detecting light transmitted through the seaweed 1.

Thus, the light rays emitted from the light source are transmitted through the light diffusion filter DF and diffused, as if by the light diffusion filter D.
The effect is that F itself becomes a linear light source, but as mentioned above, the amount of light irradiated to the light diffusion filter DF is large at the center and decreases toward the ends, so the light diffusion filter DF As shown in FIG. 3, the light rays irradiated onto the exposed area are large at the center and small at the ends. In each figure, the length of the arrow indicates the amount of light (intensity of the light ray).
The longer it is, the greater the amount of light.

The third figure shows the intensity distribution of the light beam that passed through the seaweed 1.
In Figure (b), the binarization using the threshold value as the boundary is shown in Figure 3.
c>. As is clear from these figures, the binary signal is generated not only at the portion where the foreign substance A is present, but also at both ends, causing false detection.

Note that conventionally, in order to prevent such erroneous detection, electrical processing was performed on the light receiving side.

(c) Problems to be Solved by the Invention As mentioned above, in the conventional technology, when performing slit exposure using a circular light source or a point light source, the illuminance of the exposed area becomes non-uniform, and this is used in the detection device. This poses a problem in that false detection occurs.

Furthermore, if electrical processing is performed on the light receiving side in order to solve this problem, the circuit configuration etc. will become complicated and expensive.

The present invention has been made in view of these conventional problems, and aims to realize an exposure apparatus capable of uniformly illuminating an exposed area using inexpensive means.

(d) Means for Solving the Problems The first main invention is that in an exposure apparatus equipped with a light source for illuminating an exposed area in a strip, the A translucent first light diffusion filter is interposed, which extends in a direction parallel to the direction in which the exposed portion extends, and is curved so that a central portion in the direction of extension projects toward the light source. At the same time, a semitransparent second light diffusion filter extending in a direction parallel to the first light diffusion filter is interposed.

The second main invention is a detection device that makes a band-shaped measurement light beam incident on a translucent measurement target part, detects the transmitted light beam, and detects whether or not an opaque part exists in the measurement target part. , a light source for inputting a light beam to the part to be measured, and a light source interposed between the light source and the part to be measured, extending in a direction parallel to the extending direction of the part to be measured, and a a translucent first whose central part is curved so as to protrude toward the light source;
a light diffusion filter, a semitransparent second light diffusion filter extending in a direction parallel to the first light diffusion filter, and a light detection means for detecting transmitted light from the measurement target part. It is characterized by the fact that

(e) The light rays irradiated from the action light source are transmitted through the first diffusion filter and diffused, but at this time, the amount of light irradiated from the first light diffusion filter is large in the center and goes to the edges. However, the first light diffusion filter is curved so that the center part protrudes toward the light source side, and the center part is spaced apart from the second light diffusion filter, and the end part is separated from the second light diffusion filter. Since the light rays emitted from the first light diffusion filter are close to each other, the part where the intensity of the light rays emitted from the first light diffusion filter is high is separated from the second light diffusion filter, and the part where the intensity of the light rays irradiated from the first light diffusion filter is low is separated from the second light diffusion filter. 2
Since the second light diffusion filter approaches the second light diffusion filter, a uniform light beam is emitted from the second light diffusion filter.

Note that when the light diffusion filter is irradiated with light, it acts as if the light diffusion filter itself had become a band-shaped light source.

(f) Embodiment The present invention is a method in which a curved light diffusion filter and another flat or curved light diffusion filter are attached to the prior art, and the other components are conventional. Since the technology is substantially the same as that of the above technology, only the part related to the light diffusion filter will be explained. Note that the same parts as those described in the related art are given the same reference numerals, and repeated explanation will be omitted.

FIG. 4 corresponds to FIG. 3, and the difference from FIG. The central part of the light diffusion filter DF2 in the extending direction is curved so as to protrude toward the side of the lamp I3.
This is the point.

Note that when the milky-white, translucent light diffusion filter DFI is irradiated with light from the halogen lamp 13, the light rays are scattered on the light emitting side as shown in FIG. 5, and the light diffusion filter DF becomes a light source. C2 acts so that

Moreover, regardless of the position ζ of the light source ( ) herogen lamp 13), the first diffusion filter DPI and the second light diffusion filter D
Depending on the distance from F2, the second light diffusion filter DF
The illuminance on Z changes. That is, the halogen lamp 13
When the amount of light irradiated to the first light diffusing film DFl is uniform (as shown in FIG. The amount of light returned from the first light diffusion filter DPI is smaller than that of the portion (L2)i.

Therefore, the portion where the amount of light to the second light diffusion filter DF2 is large is separated from the second light diffusion filter DF2,
When a portion with a small amount of light is brought close to the second light diffusion filter DF2, the intensity of the light rays irradiated from the second light diffusion filter DF2 is made uniform, and the exposed portion is finally exposed uniformly. is understood.

In the embodiment shown in FIG. 4, the above-mentioned theory is applied, and the central part in the extending direction of the first light diffusion filter DPI, which has a large amount of light, is separated from the second light diffusion filter DF2 and the seaweed 1. Since the end of the first light diffusion filter DPI, which is spaced apart and has a small amount of light, is close to the second light diffusion filter DF2 and the seaweed 1, the seaweed 1 is ultimately uniformly illuminated. become. Therefore, as shown in FIG. 7(b), the only part below the threshold is the foreign object A, and an accurate binary signal is output.

In the embodiment shown in FIG. 7, in order to expose the seaweed l more uniformly, a first light diffusion filter DPI and a second light diffusion filter DF2 curved in the opposite direction to the first light diffusion filter DPI are used. are arranged in parallel. Note that the curvature of the first light diffusion filter DPI is the same as that of the second light diffusion filter D.
Although it is configured so that the curvature is larger than the curvature of F2,
It is not necessary to increase the curvature of the first light diffusion filter DPI, and in some cases, the curvature of the second light diffusion filter DF2 may be increased.
The curvature of can be made larger.

In this way, by appropriately curving the first and second light diffusion filters DF and DF2, the amount of light can be controlled more finely, so that the seaweed 1 is illuminated more uniformly.

FIG. 8 is a perspective view showing the embodiment shown in FIG. 7 applied to the apparatus shown in FIG. 1.

FIG. 9 shows the light diffusion filter DP between the first and second light diffusion filters DFIDF2 and the halogen lamp 13.
This shows an embodiment in which a cylindrical convex lens 16 extending in a direction parallel to the extending direction of I and DF 2 and a reflection [15] are interposed.

FIG. 10 shows the first and second light diffusion filters DF1 and DF.
2 shows an embodiment in which a cylindrical concave mirror 24 extending in a direction parallel to the extending direction of the light diffusion filter DF is interposed between the light diffusion filter DF and the halogen lamp 13.

FIG. 11 shows an embodiment in which the second light diffusion filter DF2 is interposed between the light source and the first light diffusion filter DPI.

In this embodiment, two conveyors 2.3 are provided in parallel, but it goes without saying that the present invention can also be implemented with just one conveyor.

(G) Effects of the Invention In the present invention, the first light diffusion filter is curved so that the center portion thereof protrudes toward the light source side, and the center portion is spaced apart from the second light diffusion filter while the end portions are close to each other. Therefore, the intensity of the light rays emitted from the second light diffusion filter is made uniform, and the exposed area is finally uniformly illuminated.

When the exposed portion is uniformly illuminated in this way, the detection accuracy of the detection device is improved.

Moreover, since uniform exposure can be achieved simply by using a curved light diffusion filter, the cost of the exposure apparatus can be reduced.

[Brief explanation of the drawing]

1 to 3 show a conventional device, in which FIG. 1 is a front view, FIG. 2 is a plan view, and FIG. 3 is a logical conceptual diagram. 4 to 6 show a first embodiment of the present invention, in which FIG. 4 is a schematic diagram, FIG. 5 is a partially enlarged view, and FIG. 6 is a theoretical conceptual diagram. 7 and 8 show a second embodiment, with FIG. 7 being a schematic diagram and FIG. 8 being a perspective view of a main part. 9 to 11 are schematic diagrams showing different embodiments, respectively. 1...Seaweed, 2.3...Belt conveyor, 2a13
a...Upstream conveyor, 2b, 3b...Downstream conveyor, 4...Transparent plate, 11...Camera, 12...
Lens, 13... Halogen lamp, 14... Filter, 15... Reflection mirror 16... Cylindrical lens, 17... Stabilized power supply, 23... Conveyor roller, 24... Cylindrical concave mirror, PFI...
First polarizing filter DPI...first light diffusion filter,
DF2...Second light diffusion filter, A...Foreign matter.

Claims (1)

[Scope of Claims] 1. In an exposure apparatus equipped with a light source for illuminating an exposed area in a strip-like manner, a light source is provided between the light source and the exposed area parallel to the extending direction of the exposed area. A translucent first light diffusing filter is interposed which extends in a direction such that the central part thereof in the extending direction is curved so as to protrude toward the light source, and the first light diffusing filter An exposure apparatus characterized in that a semitransparent second light diffusion filter extending in a direction parallel to the filter is interposed. 2. The exposure apparatus according to claim 1, wherein the second light diffusion filter is interposed between the first light diffusion filter and the exposed portion. 3. The exposure apparatus according to claim 1, wherein the second light diffusion filter is interposed between the first light diffusion filter and the light source. 4. The exposure apparatus according to claim 1, wherein the second light diffusion filter is formed in a flat plate shape. 5. The exposure apparatus according to claim 1, wherein the second light diffusion filter is curved in a direction opposite to that of the first light diffusion filter. 6. A cylindrical convex lens extending in a direction parallel to the extending direction of the light diffusion filter is interposed between the light diffusion filter and the light source, according to any one of claims 1 to 5. Exposure equipment. 7. A cylindrical concave mirror extending in a direction parallel to the extending direction of the light diffusion filter is interposed between the light diffusion filter and the light source, according to any one of claims 1 to 5. Exposure equipment. 8. In a detection device that makes a belt-shaped measurement light beam incident on a semi-transparent part to be measured and detects the transmitted light beam to detect whether an opaque part exists in the part to be measured, the light beam enters the part to be measured. a light source interposed between the light source and the part to be measured, extending in a direction parallel to the extending direction of the part to be measured, with the central part in the extending direction facing the light source side; a semitransparent first light diffusion filter that is curved so as to protrude from the surface; a semitransparent second light diffusion filter that extends in a direction parallel to the first light diffusion filter; and a part to be measured. 1. A detection device comprising: a light beam detection means for detecting transmitted light beams from the light source. 9. The detection device according to claim 8, which outputs a signal indicating that an opaque portion exists in the portion to be measured when the output voltage of the light beam detection means is below a certain value. 10. The detection device according to claim 8 or 9, wherein the object to be measured is semitransparent dry seaweed, and foreign matter in the dry seaweed is detected as an opaque area.