JP2005321281A - Led lighting system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To perform stable image photographing by providing a lighting system for performing uniform illumination without being affected by the shape of a workpiece as a lighting system for performing photographing by a camera as to an image processing/inspection device. <P>SOLUTION: This LED lighting system is formed so as to have a curved shape by putting a plurality of LEDs 3 side by side on a flexible substrate 4 with the flexible substrate kept in a curved state by blocks 2 disposed at a plurality of positions on a curved guide plate 1. This lighting system makes it possible to uniformly illuminate the peripheral surfaces of a cylindrical workpiece. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to an illuminating device including a number of LEDs used as a light source for an image processing inspection apparatus using a camera.

In the production line, as an inspection device to prevent the workpiece that has been damaged during processing or conveyance from being fed to the next process, the workpiece surface is photographed by a camera, and the image data obtained by the photographing is image analysis software. 2. Description of the Related Art Image processing inspection apparatuses that perform analysis and determine the presence or absence of scratches and the determination of non-defective and defective products are known.
The image processing inspection apparatus includes a photographing camera, a photographing illumination device, a display monitor, and analysis software for analyzing a photographed image.
In the image processing inspection apparatus configured as described above, in order to perform high-precision inspection, clear image data is necessary, and a method for obtaining clear image data is, of course, a high-precision camera. In addition, lighting that illuminates the surface of the workpiece is also a very important factor.

In recent years, LEDs with low power consumption and excellent durability have been frequently used as illumination devices for image processing inspection apparatuses, and methods such as coaxial epi-illumination and reflection illumination have been used as illumination using the LEDs.
As shown in FIG. 2 of Japanese Patent Laid-Open No. 05-231844, the coaxial epi-illumination is
This is an illumination method that uses a half mirror to align the optical axis of the illumination that irradiates the workpiece with the optical axis of the camera to be observed, and observes the specularly reflected light from the workpiece surface. Only reflected light is returned, and it is the optimal illumination for planar workpieces. However, if the above-mentioned coaxial incident illumination is used on a workpiece with a cylindrical shape, the brightness of the parts near and far from the illumination device of the workpiece will be improved. A difference occurs and it is difficult to obtain a stable image.
As a method of efficiently and stably illuminating the surface of the cylindrical workpiece, a plurality of LEDs are arranged in a ring shape as shown in FIG. 6, and oblique irradiation is applied to the cylindrical workpiece arranged at the center of the ring. It is possible to obtain a stable image with the illumination method that observes the reflected light from the surface, but because the illumination is arranged above and below the workpiece, a stable image should be provided for workpieces with a short overall length However, in the case of a work having a long total length, it is difficult to stably illuminate the entire work, and a stable image cannot be provided.
JP-A-5-231844 FIG.

  The present invention enables stable image capturing by providing an illuminating device that can illuminate uniformly without being affected by the work shape as an illuminating device when performing image capturing with a camera in an image processing inspection apparatus. The purpose is to do.

  In the present invention, as means for solving the above-described problems, a plurality of LEDs are arranged on a flexible substrate, and the flexible substrate is curved by a block disposed at a plurality of locations on a curved guide plate. The LED lighting device that is held and configured in a curved shape is placed on the side surface of the cylindrical workpiece so that the LED lighting can uniformly illuminate the outer peripheral surface of the cylindrical workpiece. The work surface is configured to be photographed by the provided camera.

By configuring the LED illumination device of the image processing inspection device in a curved shape and enabling uniform illumination of the outer peripheral surface of the cylindrical workpiece, it is possible to set a wide shooting range of the image shot by the camera, The time required for the inspection can be shortened.
In addition, by adopting a device configuration that can easily increase or decrease the flexible substrate to which the block to be attached to the guide plate and the LED held by the block is attached, it can correspond to any work flowing on the line, It became possible to illuminate the outer periphery of the workpiece uniformly with LED illumination.
Further, the LED illumination device is curved rather than ring-shaped, so that the workpiece can be easily loaded into the inspection position.

  The purpose of uniformly illuminating the outer shape of the workpiece to be inspected by the image processing inspection apparatus is realized by a guide board that can be easily exchanged with a flexible substrate to which an LED is attached.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the illumination device according to the present embodiment is configured by a guide plate 1, a flexible substrate 4, and an LED 3 attached to the flexible substrate 4.
The guide plate 1 is formed in a curved shape so as to follow the workpiece outer shape to be measured, and a U-shaped block 2 is attached to a plurality of locations on the guide plate 1.
A groove portion is provided on the opposing surface of the U-shaped block 2, and the flexible substrate 4 is fitted along the guide plate 1 by fitting the flexible substrate 4 into the groove portion.
LEDs 3 are arranged in a row on the flexible substrate 4 held in a state along the guide plate 1 so that the outer shape of the workpiece to be measured can be illuminated uniformly.

Next, the arrangement of the LED lighting device and the camera will be described.
When the workpiece 5 to be inspected by the image processing inspection apparatus is a cylindrical article, the guide plate 1 is formed in a curved shape along the outer shape of the workpiece 5, and the block is fixed to the guide plate 1 2 holds the flexible substrate 4 to which the LED 3 is attached, and configures the LED illumination device so that the LED 3 is at an equal distance from the workpiece to be measured. The LED device and the camera 6 are positioned as shown in FIG. To place.
When the entire length of the target work is long and the LED illumination as shown in FIG. 4 is insufficient in light quantity and a stable image cannot be obtained, a plurality of blocks 2 are mounted on the guide plate 1 as shown in FIG. By holding a plurality of flexible substrates 4 to which the LEDs 3 are attached, the amount of light is increased and a clear image can be obtained.
In this embodiment, the guide plate is formed in a curved shape in order to arrange the LEDs at a uniform position with respect to the cylindrical workpiece. However, the LED illumination device of the present invention is limited to this embodiment. It is possible to deal with various shaped workpieces by changing the shape of the guide plate instead of the object.

  By adopting a simple device configuration, it is possible to easily cope with a design change according to the workpiece, so that it is possible to deal with various workpieces.

Plan view of the illumination device of this embodiment

Sectional view of the main part of the first embodiment

Plan view of positional relationship between LED lighting device and workpiece

Drawing which shows the positional relationship of the LED lighting apparatus of Example 1, and a camera and a workpiece | work

Drawing which shows the positional relationship of the LED lighting apparatus of Example 2, and a camera and a workpiece | work

A figure showing a conventional example

Explanation of symbols

1 Guide plate 2 Block 3 LED
4 Flexible substrate 5 Work 6 Camera 7 Ring shape illumination

Claims (3)

  In an LED lighting device comprising a curved guide plate, blocks disposed at a plurality of locations on the guide plate, and a flexible substrate on which LEDs held in the block are arranged, LEDs are arranged in a row. An LED lighting device characterized by holding a flexible substrate provided in a curved shape.   The LED lighting device according to claim 1, wherein the LED lighting device can be easily replaced with a guide plate having a different bending amount.   The LED lighting device according to claim 1 or 2, wherein a block for holding a flexible substrate to which the LED is attached can be easily added.

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