JPH07203290A - Indirect lighting device for web monitor system - Google Patents

Abstract

PURPOSE:To obtain the uniform lighting by which no shadow is formed on a detection plate by placing the indirect lighting device having a dome shaped reflecting concaved face with a strobe valve arranged thereon between a CCD camera and a web. CONSTITUTION:The indirect lighting device having 8 dome shaped reflecting concaved face with a strobe valve 3 arranged thereon is placed between a CCD camera 1 and a web 4. The reflecting concaved face is a smoothed face, an uneven face or an emboss processed face depending on applications. Thus, the light is directed to the web 4 being an object from every angle to light up the web 4 uniformly. Or the reflecting face might be part of a cone or a polygonal cone.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to indirect illumination of a web monitor system for capturing a still image in synchronization with a strobe used in a printer, a converter of paper, resin, film, fiber, metal, etc.

[0002]

2. Description of the Related Art A lighting device provided in a conventional web monitor system is a CC installed vertically to a web.
Since the direct illumination system irradiates the strobe from the side of the D camera, the brightness of the subject is higher on the side closer to the strobe than on the side far from the strobe, and it is not possible to accurately compare the color density of the web on the monitor. Moreover, in the conventional illumination system, when a web printed on a transparent material is monitored, the shadow of the printed part is cast on the white inspection plate provided on the back side of the web and is projected on the CCD camera through the transparent part of the web. Therefore, there is a problem in quality control such that it is difficult to distinguish it from dirt on the web. Figure 1
Shows an example of a conventional lighting device, 1 is a CCD camera, 3
Is a strobe valve, 4 is a web, 5 is a printing ink, 6 is a white inspection plate, and 8 is a trace of direct light.
Reference numeral 7 indicates a shadow of the ink on the printing portion. FIG. 2 shows an example of an image of two circles projected by the illumination system shown in FIG. Reference numeral 4 is a transparent web, 5 is a round ink portion on the web, 6 is a white inspection plate, and 7 is a shadow of the round ink portion dropped on the white inspection plate 6. The shaded line 11 indicates that the circle farther from the strobe has a smaller amount of light than the circle close to the strobe, and thus has a low brightness.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a lighting device for a web monitor system which solves the above problems.

[0004]

The illumination device of the present invention which achieves the above object is characterized in that a dome-shaped or conical concave reflecting surface having a strobe light source is provided between the webs of the CCD camera. .

[0005]

Since the illuminating device of the present invention is provided with a dome-shaped or conical concave reflecting surface provided with a stroboscopic bulb, the light to the web is uniformly reflected from all directions toward the object by the internal reflection of the concave surface. It is possible to provide lighting that does not cast shadows on the autopsy plate.

[0006]

3 and 4 show an example of an illuminating device of the present invention, 1 is a CCD camera, 2 is a dome-shaped concave reflecting surface or a cone / polygonal pyramid inner reflecting surface, 3 is a strobe bulb,
Reference numeral 4 indicates the web, 5 indicates the printing portion ink, 6 indicates the white inspection plate, 7 indicates the shadow of the printing portion ink, and 8 indicates that the strobe light is internally reflected and strikes the web from any angle. 9 is a fiber, a lens for propagating strobe light,
Reference numeral 10 denotes a prism and the like, and 10 denotes a shield plate for direct light of strobe light to the web. The dome-shaped or conical internal reflection surface of 2 may be a smooth surface, an uneven surface or an embossed surface depending on the application.

[0007]

Since the illuminating device for the web monitor system of the present invention uses indirect illumination utilizing the internal reflection of a dome shape or a cone / polygon cone, the light is emitted at any angle as shown by the arrow 8 in FIG. 3/4. To the web, which is the subject. Therefore, the amount of light on the web is uniform regardless of the distance from the strobe, and the shadow of the printed part on the transparent web is smaller than the printed part on the inspection plate and is hidden behind it so that the web is transparent. It is not projected to the CCD camera through the part.

[Brief description of drawings]

FIG. 1 is a side view of direct illumination of a conventional web monitor system.

2] Two circles (printed part) on the transparent web projected by the illumination of FIG. 1 and a shadow cast on the inspection board.

FIG. 3 is a side view of an example of indirect illumination according to the invention of claim 1, wherein a dome-shaped concave reflecting surface is provided.

FIG. 4 is a side view of an example of indirect illumination according to the invention of claim 2, wherein a conical concave reflecting surface is provided.

[Explanation of symbols]

1-CCD camera 2-dome-shaped or conical concave reflecting surface 3-strobe 4-web 5-printing ink 6-white inspection plate 7-shadow of printing 8-light trace 9-fiber lens prism 10- Light shield

Claims (2)

[Claims] 1. A device installed between the CCD camera and the web,
An indirect illumination device having a part of a dome-shaped concave reflection surface on the inner surface of which direct or indirect light is emitted by a strobe. The concave reflecting surface may be a smooth surface, an uneven surface or an embossed surface depending on the application. 2. A device installed between the CCD camera and the web,
An indirect lighting device in which a part of a cone or a polygonal cone whose inner surface is irradiated with direct or indirect light by a strobe serves as an inner reflecting surface. The inner reflective surface is a smooth surface, an uneven surface or an embossed surface depending on the application.