JP2003077319A - Lighting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting device with low power consumption and heat value, enabled to irradiate a web with light at high illuminance. SOLUTION: The lighting device comprises a light source 6 arranged so as to face a drum 2 drawing out a web 1, and a reflection mirror 8 arranged parallel with the axis line of the drum 2, formed into a concavely curved mirror surface 7 enabled to irradiate the light L emitted from the light source 6 toward the surface to be tested on the web 1 held by the drum 2. The concavely curved mirror surface 7 is formed so that the shape of the cross section observed in the direction of the axis line of the drum 2 is an ellipse E of which, virtual part overlaps with the peripheral surface of the drum 2, and that one focus F1 is located at the surface to be tested on the web 1. The light source 6 is located at the other focus F2, and the light L emitted from the light source 6 is made to linearly irradiate the surface to be tested on the web 1 by the concavely curved mirror surface 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illumination device used in an image processing inspection system.

[0002]

2. Description of the Related Art FIG. 4 shows an example of an information collecting unit of an image processing inspection system. This information collecting unit is a web (roll paper or long film) in which different color patterns are sequentially printed by a rotary printing machine. ) 1 to the non-inspection target surface (non-printing surface) and to feed the web 1 from the upstream side to the downstream side, and to the inspection target surface (printing surface) of the web 1 carried by the drum 2. A light source 3 that emits light L, and the light source 3
Image signal corresponding to the intensity of light reflected by the web 1 which has a reflection plate 4 provided so as to be located on the side opposite to the drum 1 and a large number of CCDs (charge coupled devices) arranged in a line in the axial direction of the drum 2. And a photographing means 5 for outputting

In the figure, P is the collimation line of the photographing means 5.

The image signal output by the photographing means 5 is transmitted to an information processing unit such as a microcomputer, and the information processing unit determines whether or not there is a defect on the surface to be inspected of the web 1.

[0005]

In the information collecting section as shown in FIG. 4, when the light source 3 has a low illuminance, the CCD of the photographing means 5 accumulates the energy of the reflected light from the surface to be inspected of the web 1. As a result, it takes a long time to convert the image signal into an image signal, so that the inspection time cannot be shortened by increasing the delivery speed (scanning speed) of the web 1.

If the scanning speed is lowered according to the low illuminance, the image signal obtained by the photographing means 5 is affected by the illuminance fluctuation (flickering / blinking) of the room lighting caused by the commercial power supply frequency. .

Further, if the f value is increased by enlarging the lens diameter of the photographing means 5 at a low illuminance, the depth of focus is decreased and the resolution is lowered, or the value is set to a sufficient value in the information processing section. When an image signal is processed with a high amplification factor, noise such as the above-mentioned illuminance fluctuation is also amplified together with the image signal, so it is difficult to set the quality judgment reference value such as density strictly, and highly accurate inspection is required. I can't do it.

Therefore, in order to efficiently perform a highly accurate inspection, it is necessary to use the light source 3 which emits a large amount of light.
Power consumption and heat generation tend to increase in proportion to the amount of light.

The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to provide an illuminating device capable of irradiating a web with high illuminance and having a small amount of power consumption and a calorific value.

[0010]

In order to achieve the above object, in the illumination device according to the first aspect of the present invention, a light source provided so as to face the surface to be inspected of the web that continuously passes through the transport path. , A reflecting mirror having a concave curved mirror surface extending in the width direction of the web and capable of emitting the light emitted from the light source toward the inspection target surface of the web, and the shape of the concave curved mirror surface viewed from the side of the transport path, Along a virtual ellipse partly overlapping the transport path, one focus of the ellipse is positioned on the inspection surface of the web, and the light source is positioned at the other focus of the ellipse.

In the lighting device according to the second aspect of the present invention,
A drum for feeding the web in contact with the non-inspected surface of the web, a light source provided so as to face the outer peripheral surface of the drum, and a web arranged in parallel to the drum axis and carrying light emitted from the light source on the drum. And a reflecting mirror having a concave curved mirror surface that can be emitted toward the surface to be inspected, and the shape of the concave curved mirror surface viewed parallel to the drum axis direction is along a virtual ellipse partly overlapping the drum outer peripheral surface and The focus of one of the ellipses is set so as to be located on the surface to be inspected of the web carried on the drum, and the light source is located at the other focus of the ellipse.

Further, in the illuminating device according to the third aspect of the present invention, one of the foci of the virtual ellipse is seen at a predetermined position of the reflecting mirror from the photographing means which extends in the web width direction and is arranged outside the reflecting mirror. It has possible slits.

That is, in the illuminating device according to claim 1 of the present invention, the light diverged by the light source located at the other focal point of the virtual ellipse is elliptical by the concave curved mirror surface of the reflecting mirror along the ellipse. The light is focused on one of the focal points and is irradiated onto the surface to be inspected of the web passing through the transport path.

Similarly, in the illumination device according to the second aspect of the present invention, the light diverged by the light source located at the other focal point of the virtual ellipse is reflected by the concave curved mirror surface of the reflecting mirror along the ellipse. The light is focused on one focus of the ellipse and irradiated onto the surface of the web carried by the drum to be inspected.

Further, in the illuminating device according to the third aspect of the present invention, the irradiation means on the surface of the web to be inspected is photographed by the photographing means arranged outside the reflecting mirror through the slit formed in the reflecting mirror. To do.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an information collecting section of an image processing inspection system using an example of the embodiment of the illuminating device of the present invention. In the figure, the same reference numerals as those in FIG. Is represented.

This information collecting section is in parallel with the drum 2 axis so as to face the drum 2 which is in contact with the non-inspected surface of the web 1 and which feeds the web 1 from the upstream side to the downstream side, and the outer surface of the drum 2. Reflection in which the arranged light source 6 and the concave curved mirror surface 7 capable of emitting the light L emitted from the light source 6 in parallel with the axis of the drum 2 toward the inspection target surface of the web 1 carried on the drum 2 are formed. The mirror 8 is provided, and the photographing means 5 is arranged outside the reflecting mirror 8.

The light source 6 is a fluorescent lamp which is a general tubular discharge lamp, an array in which LEDs (light emitting diodes) are arranged, or the like, which has a light illuminance distribution in the axial direction of the drum as uniform as possible, or A point light source that emits strong light radially from one point is used.

The shape of the concave curved mirror surface 7 has a length A1A2 that cuts the coordinate axis X is 2a (major axis) and a length B1B2 that cuts the coordinate axis Y is 2b (minor axis) when viewed in the axial direction of the drum 2, It is set so as to follow an imaginary ellipse E, a portion of which overlaps the surface, one focus F1 of the ellipse E is located on the inspection target surface of the web 1 carried on the drum 2, and the light source 6 is
It is located at the other focal point F2 of the ellipse E.

Further, the reflecting mirror 8 is provided with a slit 9 parallel to the axis of the drum 2 so that the collimation line P of the photographing means 5 can see one focus F1 of the ellipse E.

The relative position of the drum 2, the photographing means 5 and the concave curved mirror surface 7 is an ellipse E on the extension line of the collimation line P of the photographing means 5.
One focus F1 and the rotation center Q of the drum 2 are set to be aligned.

Further, end plates 10 parallel to the end surface of the drum 2 are fixed to both ends of the reflecting mirror 8 in the axial direction.

That is, in the information collecting section shown in FIG. 1, a part of the light L emitted from the light source 6 is directly incident on the surface to be inspected of the web 1 carried by the drum 2, and most of the remaining light is emitted. L is reflected by the concave curved mirror surface 7 and is focused on one focus F1 of the virtual ellipse E, and the drum 2 is transferred to the surface to be inspected of the web 1.
It is incident in a line parallel to the axis.

Further, when the light source 6 is a point light source, a part of the light L emitted from the light source 6 is directly incident on the surface of the web 1 to be inspected, and as shown in FIG. Most of the remaining light L emitted radially from the light source 6 located
Is reflected by the concave curved mirror surface 7 of the reflecting mirror 8, passes through the focal point F1 on the surface of the web 1 to be inspected, and is incident over the entire length of the straight line Z parallel to the axis of the drum 2 (see FIG. 1).

Therefore, the illuminance of the portion of the surface of the web 1 to be inspected facing the photographing means 5 through the slit 9 is selectively increased, and even if the light source 6 having a small light quantity is used, the light L
Can be effectively used, so that it is possible to reduce power consumption and heat generation.

In addition to this, since the irradiated portion of the surface to be inspected of the web 1 is covered with the reflecting mirror 8, the image signal obtained by the photographing means 5 is not affected by the illuminance fluctuation of the room illumination.

FIG. 3 shows an information collecting section of an image processing inspection system using another example of the embodiment of the illumination device of the present invention. In the figure, the parts denoted by the same reference numerals as those in FIG. Represent the same thing.

The information collecting section extends in the width direction of the web 1 that linearly passes through the transport path and is arranged so as to face the surface to be inspected of the web 1, and the light source 6 extends in the width direction of the web 1 and the light source. A reflecting mirror 8 having a concave curved mirror surface 7 capable of emitting the light L emitted by 6 toward the web 1 is provided, and the photographing means 5 is arranged outside the reflecting mirror 8.

The shape of the concave curved mirror surface 7 is set so as to be along an imaginary ellipse E that partially overlaps the conveyance path when viewed from the side, and one focus F1 of the ellipse E moves along the conveyance path. The light source 6 is located on the inspection target surface of No. 1 and the ellipse E
Is located at the other focal point F2.

Further, the reflecting mirror 8 is provided with a slit 9 extending in the width direction of the web 1 so that the collimation line P of the photographing means 5 can see one focus F1 of the ellipse E.

That is, in the information collecting section shown in FIG. 3, a part of the light L emitted from the light source 6 is directly incident on the surface to be inspected of the web 1, and most of the remaining light L is the concave curved mirror surface 7. It is reflected by the laser beam and is focused on one focus F1 of the virtual ellipse E and is incident on the surface of the web 1 to be inspected in a linear shape extending in the width direction.

Therefore, the illuminance of a portion of the surface of the web 1 to be inspected facing the photographing means 5 through the slit 9 is selectively increased, and even if the light source 6 having a small light quantity is used, the light L
Can be effectively used, so that it is possible to reduce power consumption and heat generation.

In addition to this, since the irradiation portion of the surface to be inspected of the web 1 is covered with the reflecting mirror 8, the image signal obtained by the photographing means 5 is not affected by the illuminance fluctuation of the room illumination.

The illumination device of the present invention is not limited to the above-mentioned embodiments, and it goes without saying that changes can be made without departing from the scope of the present invention.

[0036]

As described above, according to the lighting device of the present invention, various excellent effects as described below can be obtained.

(1) In the illumination device according to claim 1 of the present invention, the light diverged by the light source located at the other focal point of the virtual ellipse is elliptical by the concave curved mirror surface of the reflecting mirror along the ellipse. Since the light is focused on one of the focal points and is linearly incident on the inspection surface of the web that passes through the transport path, the illuminance in the irradiation range is increased even with a light source with a small amount of light, reducing power consumption and heat generation. It becomes possible to plan.

(2) In the illumination device according to the second aspect of the present invention, the light diverged by the light source located at the other focal point of the virtual ellipse is elliptical by the concave curved mirror surface of the reflecting mirror along the ellipse. The light is focused on one side and linearly incident on the inspection surface of the web carried by the drum, so the illuminance of the irradiation range is increased even with a light source with a small amount of light, and power consumption and heat generation are reduced. Can be achieved.

(3) In any one of the illumination device according to claim 1 or claim 2 of the present invention, since the irradiation portion of the inspection target surface of the web is covered with the reflecting mirror, the image signal obtained by the photographing means is It is not affected by fluctuations in illuminance of indoor lighting.

(4) In the illuminating device according to the third aspect of the present invention, the irradiation portion of the surface to be inspected of the web is irradiated by the photographing means arranged outside the reflecting mirror through the slit formed in the reflecting mirror. Since the photograph is taken, the photographing means is not affected by the heat generation of the light source.

[Brief description of drawings]

FIG. 1 is a conceptual diagram showing an information collecting unit of an image processing inspection system using an example of an embodiment of a lighting device of the present invention.

FIG. 2 is a conceptual diagram showing an optical path when light emitted from a point light source is reflected by a concave curved mirror surface.

FIG. 3 is a conceptual diagram showing an information collecting unit of an image processing inspection system using another example of the embodiment of the illumination device of the present invention.

FIG. 4 is a conceptual diagram showing an example of an information collecting unit of a conventional image processing inspection system.

[Explanation of symbols]

1 web 2 drums 5 Means of photography 6 light source 7 concave curved mirror surface 8 reflector 9 slits E virtual ellipse F1 one focus F2 the other focus L light

Claims (3)

[Claims] 1. A light source provided so as to face an inspection target surface of a web continuously passing through a conveying path, and light emitted in the width direction of the web and emitted by the light source can be emitted toward the inspection target surface of the web. With a reflecting mirror having a concave curved mirror surface,
The shape of the concave curved mirror surface viewed from the side of the transfer path is determined so that it is along an imaginary ellipse that partially overlaps the transfer path and one focus of the ellipse is located on the inspection target surface of the web. Is located at the other focal point of the ellipse. 2. A drum for sending out the web in contact with a non-inspection surface of the web, a light source provided so as to face the outer peripheral surface of the drum, and a drum which emits light emitted from the light source and arranged in parallel with the drum axis. And a reflecting mirror having a concave curved mirror surface that can be emitted toward the surface to be inspected of the web carried by, and the shape of the concave curved mirror surface viewed parallel to the drum axis direction,
Along a virtual ellipse that partially overlaps the outer peripheral surface of the drum, one of the foci of the ellipse is positioned so as to be located on the surface to be inspected of the web carried on the drum, and the light source is located at the other focus of the ellipse. A lighting device characterized by being made. 3. The slit according to claim 1, wherein a slit that extends in the width direction of the web and allows one of the foci of the virtual ellipse to be seen from the photographing means arranged outside the reflector is provided at a predetermined position of the reflector. 2. The lighting device according to any one of 2.