JP2010203922A - Lighting device for inspection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lighting device for inspection capable of being used even if the gap between rollers is narrow and capable of irradiating a translucent film surface at a high illuminance without loss of an introduced light. <P>SOLUTION: The lighting device for inspection includes a transparent solid light guide plate in which a light introduced from a base end surface is led out from a tip end surface opposite to the base end surface, and a light source arranged at a position where the injected light is introduced from the base end surface into the light guide plate. The lighting device for inspection, being inserted between the rollers, is arranged at the position where the tip end surface of the light guide plate overviews the translucent film surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an illumination device for inspecting a translucent film that is carried while being stretched by a roller.

  Conventionally, when performing an in-line high-speed inspection of a light-transmitting film, image information on the surface of the light-transmitting film M being carried while being stretched by a roller R is successively used using a line sensor camera C as shown in FIG. A surface defect or the like is detected by continuously capturing and detecting a part with different brightness in an image information processing apparatus (not shown). The illuminating device 10 used at that time includes a reflector 12 formed by applying a white paint on the inner surface of a casing 11 having a long rectangular parallelepiped shape as a light guide member, and 1 inside the casing. It is known that light is introduced from a plurality of LEDs 13 arranged in a row, and uniform line light is derived while being reflected and diffused by the reflector 12, and the illuminating device 10 is inserted between the rollers R so as to transmit light. The M surface is irradiated with light. The side wall of such a hollow casing 11 has a predetermined thickness in order to maintain a predetermined shape.

  By the way, if the distance L between the rollers R is long, the translucent film M is easily bent and vibrated, and it becomes difficult to obtain a clear image. Therefore, it is preferable that the distance L between the rollers R is short. However, in the illuminating device 10 including the reflector 12 formed on the inner surface of the casing 11 as a light guide member, the distance L between the rollers R must be set wider than the required line light width by the casing wall thickness. Therefore, the distance L between the rollers R cannot be shortened sufficiently. Although the distance L between the rollers R can be shortened by using a roller R having a short diameter, if the curvature of the roller R is large, the stretched translucent film M is easily cut, There is a problem in that the translucent film M is liable to have large habits and causes quality deterioration. For this reason, it is necessary to use a roller R having a predetermined size or larger.

  Further, in the above-described lighting device 10, a part of light is refracted at the interface between the reflector 12 and the casing 11 and absorbed by the casing 11, and the light transmission efficiency is deteriorated. Therefore, the brightness of the derived light is not sufficient.

  On the other hand, there is also known an apparatus that inspects the light-transmitting film by irradiating light toward the roller that conveys the light-transmitting film (Patent Document 2). Even the scratches and dirt on the roller surface may be detected, noise is easily included in the inspection result, and it is difficult to perform a highly accurate inspection.

JP 2005-283563 A JP 2002-250695 A

  The present invention has been made in view of such a problem, and provides an inspection illumination device that can be used even when the distance between rollers is narrow, and can irradiate the surface of the light-transmitting film with high illuminance without loss of introduced light. This is the main intended issue.

  That is, the inspection illumination device according to the present invention is for performing surface inspection or mark detection of a translucent film carried while being stretched by at least a pair of rollers, and light introduced from the base end face is A transparent solid light guide plate led out from the front end surface facing the base end surface, and a light source provided at a position where the emitted light is introduced into the light guide plate from the base end surface, and It is inserted between rollers, The front end surface of the said light-guide plate is provided in the position which wants the said translucent film.

  In such a case, by using a transparent solid light guide plate as the light guide member, the distance between the rollers is set to the same width as the line light, that is, to irradiate the light-transmitting film with light. Even if it is narrowed to the minimum necessary width, the light guide plate can be inserted, so that the surface of the translucent film can be imaged with vibration suppressed. In addition, the light introduced from the base end face to the light guide plate proceeds toward the front end face while being totally reflected, and is derived from the front end face, so that the light introduced from the base end face can be led out almost without loss. The surface of the translucent film can be irradiated with high illuminance. Therefore, according to the present invention, it is possible to obtain a clear image of the translucent film, and thus it is possible to perform a highly accurate inspection.

  The light guide plate may be coated with a reflective film whose outer surface is subjected to aluminum vapor deposition or the like in order to more securely prevent light leakage from the outer surface.

  According to the present invention having such a configuration, a clear image of the surface of the light-transmitting film can be acquired and a highly accurate inspection can be performed.

It is a typical longitudinal section of the lighting installation for inspection concerning one embodiment of the present invention. It is a typical perspective view of the illuminating device for a test | inspection which concerns on the same embodiment. It is a typical longitudinal cross-sectional view of the conventional illuminating device for a test | inspection.

  An embodiment of the present invention will be described below with reference to the drawings.

  The inspection illumination device 1 according to the present embodiment is for detecting surface defects or the like of the translucent film M that is carried while being stretched by a pair of rollers R. As shown in FIG. The light guide plate 2 and the LED 3 provided to face the base end face 21 of the light guide plate 2 are provided.

Each part will be described in detail.
The light guide plate 2 is made of, for example, a resin that has a transparent, solid, thin rectangular plate shape. The light guide plate 2 has a base end surface 21 as a light introduction surface and a front end surface 22 that faces the light introduction surface. The light introduced from the base end face 21 proceeds toward the front end face 22 with almost no loss while being totally reflected on the outer side face of the light guide plate 2 due to a difference in refractive index with the outside, and is led out from the front end face 22. A light diffusing plate 23 is disposed on the front end surface 22 to equalize the luminance of light derived from the front end surface 22.

  As the light diffusing plate 23, for example, the surface of the light-transmitting substrate is provided with irregularities by embossing or embossing or the like, and the surface is configured as a ground glass surface, or white paint is provided on the surface of the light-transmitting substrate with a gap. Various materials that have been imparted with light diffusibility using light scattering, such as those coated with a light-transmitting substrate and particles that cause light scattering in a light-transmitting substrate, can be used.

  The outer surface of the light guide plate 2 serves as an inwardly reflecting surface that totally reflects light. When light travels through the light guide plate 2, the light is reflected and mixed inward by the outer surface. Mated and mixed. The light guide plate 2 is held so as to be positioned on the optical axis of the LED 3 by a holding member 5 attached on a wiring substrate 4 described later.

  The LED 3 is a surface-mounted power LED, for example, and emits light toward the base end face 21 of the light guide plate 2. The power LED is a high-luminance type LED that can continuously flow a current of 200 mA or more. As shown in FIG. 2, a plurality of such LEDs 3 are arranged in a line on the strip-like flat wiring board 4 that is a unit board so as to face the base end face 21 of the light guide plate 2. The light emitted from the LEDs 3 enters the inside of the light guide plate 2 from the base end face 21, and the light emitted from the individual LEDs 3 is diffused and mixed there, whereby variation is reduced and uniformized. Thus, line-shaped uniform light is emitted from the front end surface 22 of the light guide plate 2.

  A method for performing the surface inspection of the translucent film M using such an inspection illumination device 1 will be described below. First, the light guide plate 2 of the inspection illumination device 1 is inserted between the rollers R on which the transparent film M to be inspected is stretched. At this time, since the space between the rollers R is set to be extremely narrow, the vibration of the translucent film M is suppressed. When the LED 3 of the inspection illumination device 1 is turned on, the light emitted from the LED 3 is introduced into the interior from the proximal end surface 21 of the light guide plate 2 and is led out from the distal end surface 22 as line-shaped light. Since the line-shaped light is sufficiently mixed by repeating reflection and diffusion in the light guide plate 2, it is uniform and uniform light. When the line-shaped light is irradiated toward the translucent film M, the surface of the translucent film M is illuminated with uniform illuminance across both ends. While irradiating the transparent film M with uniform line light, the area irradiated with the light is imaged by a line sensor camera C provided above the transparent film M. Accordingly, image information on the surface of the translucent film M carried by the rotating roller R is continuously taken in one after another, and a surface defect or the like is detected by detecting a part having a different brightness in an image information processing apparatus (not shown). Is detected.

  In the inspection lighting device 1 according to such an embodiment, by using the transparent solid light guide plate 2 as the light guide member, the distance L between the rollers R is set to the same width as the line light, That is, since the light guide plate 2 can be inserted even if it is narrowed to the minimum necessary width for irradiating the light to the light-transmitting film M, the surface of the light-transmitting film R is imaged with vibration suppressed. be able to. Further, since the light introduced from the base end face 21 to the light guide plate 2 travels upward while being totally reflected and is derived from the front end face 22, the light introduced from the base end face 21 can be led out with almost no loss. Therefore, the surface of the translucent film M can be irradiated with high illuminance. Therefore, according to this embodiment, since a clear image of the translucent film M can be acquired, it is possible to perform a highly accurate inspection.

  The present invention is not limited to the above embodiment.

  For example, the outer surface of the light guide plate 2 may be coated with a reflective film formed by vapor deposition of aluminum or the like, so that the reflective film acts as a mirror and leaks light from the outer surface of the light guide plate 2. It can be prevented more firmly.

  In addition, the present invention is not limited to the above-described embodiments, and may be configured by appropriately combining some or all of the various configurations described above without departing from the spirit of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Illuminating device for inspection 2 ... Light guide plate 3 ... LED
R ... Roller

Claims (2)

For performing surface inspection or mark detection of a translucent film carried while being stretched by at least a pair of rollers,
A transparent solid light guide plate in which light introduced from the base end surface is led out from the front end surface facing the base end surface;
A light source provided at a position where the emitted light is introduced into the light guide plate from the base end surface, and
An inspection illumination device, wherein the illumination device is inserted between the rollers, and a front end surface of the light guide plate is provided at a position where the light-transmitting film is desired.   The illumination device for inspection according to claim 1, wherein the light guide plate has an outer surface covered with a reflective film.