JP2011222239A - Lighting system and inspection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lighting system including light emitting diodes which can be easily installed at the same angle, while achieving easy manufacturing, high efficiency and excellent uniformity.SOLUTION: An optical element 34 constitutes a cylindrical lens which has characteristics to irradiate an inspection region with light of the light-emitting diode 33, including an outgoing face 36 of the light. A light incident face 37 opposed to the outgoing face 36 is planar and has a groove 38 having the same shape as the front cross-sectional shape of the light emitting part 35 of the plurality of light-emitting diodes 33. The plurality of light-emitting diodes 33 are installed by inserting and positioning the light emitting parts 35 in the groove 38 of the optical element 34.

Description

  The present invention relates to an illuminating device and an inspection device, and more particularly, to an application for illuminating the surface of an inspection object such as a printed circuit board for electronic industry, a glass substrate for manufacturing a liquid crystal display, or a printed material. The present invention relates to an illumination device that uses a light-emitting diode as a light source, and an inspection device using the illumination device.

  As an appearance inspection device that inspects the surface of a printed circuit board for electronic industry or a glass substrate for manufacturing a liquid crystal display, for example, a primary that is long in a direction intersecting the conveyance direction while conveying a substrate that is an inspection object in one direction There is an apparatus in which a surface of a substrate is photographed by an imaging apparatus using the original imaging element, and the obtained image is processed to detect a defective portion. In such an inspection apparatus, an illuminating device that illuminates the surface of the object to be inspected is used. However, when an imaging device having a one-dimensional imaging range is used, the illumination range is also defined as the imaging range. Those that uniformly illuminate the same one-dimensional region are used.

JP 2003-132708 A

In the illumination device as described above, it is conceivable to use a light emitting diode as a light source. In the general illumination field, as shown in Patent Document 1, it is considered that a large number of light emitting diodes are arranged in a line on a substrate, and the light emitting portion is covered with a cover and scattered to suppress unevenness in the amount of light. It is done. However, if the light is scattered by the cover in this way, the amount of light is lost and the amount of light applied to the inspection target portion is reduced, and the efficiency is lowered. It is also conceivable that an optical system such as a Fresnel lens is provided on the front surface of a line in which a large number of light emitting diodes are arranged in a line without using such a cover, so that the portion to be inspected is condensed and irradiated. However, in this case, it is necessary to assemble many light-emitting diodes in the same direction, making the assembly difficult and costly.If the light-emitting diodes are tilted, they cannot be condensed well, causing uneven illumination, There is a problem in that the efficiency decreases due to poor transmittance due to light scattering due to a step.
In recent years, the substrate to be inspected has become larger, and the imaging width has been increased accordingly. On the other hand, the resolution required for imaging and inspection has been reduced. It is necessary to increase the efficiency by sufficiently condensing in the direction orthogonal to the line. Along with that, for example, a method of mounting a large number of cannonball type light emitting diodes with a small diameter is taken, but a small type of cannonball type light emitting diode has high directivity, and in order to illuminate the line uniformly Therefore, it is necessary to adjust the mounting angle with higher accuracy, which makes manufacturing difficult.

  The present invention has been made in view of the above-described problems, and uses a lighting device that can easily arrange the mounting angles of light-emitting diodes, can be easily manufactured, has high efficiency and good uniformity, and the lighting device. The object is to provide an inspection device.

  According to the first aspect of the present invention, a plurality of light emitting diodes having a light emitting portion formed of a translucent material, and a groove corresponding to the shape of the light emitting portion of the plurality of light emitting diodes are formed on one surface. And an optical element having an emission surface for emitting light on the surface, wherein the light emitting diodes are positioned by inserting the light emitting portions of the plurality of light emitting diodes into the grooves.

  According to the second aspect of the present invention, a plurality of light emitting diodes having a light emitting portion formed of a light transmissive material, and a plurality of insertion holes corresponding to the shape of the light emitting portion of the plurality of light emitting diodes are arranged side by side. And an optical element formed with an emission surface for emitting light on the other surface, and positioning the light emitting diode by inserting the light emitting portions of the plurality of light emitting diodes into the plurality of insertion holes. It is an illuminating device.

  According to a third aspect of the present invention, in the illuminating device according to the first or second aspect of the present invention, the exit surface of the optical element is a cylindrical lens that substantially condenses light at an illuminated position.

  According to a fourth aspect of the present invention, in the illuminating device according to the third aspect, the exit surface of the cylindrical lens is a spherical surface that is substantially condensed at an illuminated position.

  According to a fifth aspect of the present invention, in the illumination device according to the third aspect of the present invention, the exit surface of the cylindrical lens is an aspherical surface that is substantially condensed at an illuminated position.

  The invention according to claim 6 is supported by the support device that supports the inspection object, the imaging device that images a long inspection region in one direction in the inspection object supported by the support device, and the support device. A moving mechanism for relatively moving the inspection object and the imaging device in a direction perpendicular to the longitudinal direction of the inspection area, and a lighting mechanism that is arranged to illuminate the inspection area that is long in the one direction on the surface of the inspection object. An inspection device comprising: the illumination device according to any one of claims 1 to 5.

  According to the present invention, it is possible to obtain an illumination device and an inspection device that can easily align the mounting angles of LEDs, are easily manufactured, have high efficiency, and have good uniformity.

1 is a schematic diagram showing an inspection apparatus according to a first embodiment of the present invention. It is an optical path diagram which shows 1st Embodiment of a light source. It is an optical path figure which shows the modification of 1st Embodiment of a light source. It is a figure which shows 2nd Embodiment of a light source. It is an optical path diagram which shows 2nd Embodiment of a light source. It is a figure which shows the illumination intensity distribution in the to-be-illuminated position by each embodiment.

  FIG. 1 is a schematic diagram showing an inspection apparatus 1 according to the first embodiment of the present invention. FIG. 1 (A) shows the entire inspection apparatus 1, and FIG. Show. The inspection apparatus 1 is an appearance inspection apparatus that images the surface of an inspection object such as a printed circuit board for electronic industry, a glass substrate for manufacturing a liquid crystal display, or a printed material, and inspects a wiring pattern or a defect on the surface. It comprises a stage 2 that supports a substrate W that is an object, an inspection head 3 for imaging the surface of the substrate W supported by the stage 2, and a moving mechanism 4 that moves the stage 2 relative to the inspection head 3. ing.

  The stage 2 supports the substrate W in a state where the substrate W is sucked by a suction mechanism (not shown) and the flatness of the substrate W is maintained. The inspection head 3 is installed on the moving path of the stage 2 by the moving mechanism 4 by a gate-type support (not shown) straddling the moving mechanism 4. The inspection head 3 is provided with an imaging device 31 that captures an image of the surface of the substrate W and an illumination device 32 that illuminates an imaging region by the imaging device 31. The imaging device 31 is a one-dimensional imaging device for imaging a long inspection region in a direction orthogonal to the moving direction of the stage 2 by the moving mechanism 4 on the surface of the substrate W supported on the stage 2 and an optical system for the same ( Neither is shown). The moving mechanism 4 is composed of a ball screw or a linear motor.

  The illuminating device 32 is arranged toward the inspection region in order to illuminate the imaging region by the imaging device 31 on the surface of the substrate W, that is, the inspection region. The details of the illumination device 32 will be described with reference to FIG. 1B. The illumination device 32 includes a plurality of light emitting diodes 33 as light sources and an optical element 34 for irradiating the inspection region with light from the plurality of light emitting diodes 33. . Each of the light emitting diodes 33 is of a so-called bullet type, and has a light emitting part 35 formed by molding with a translucent resin material. The front surface of the light emitting unit is a spherical surface. The optical element 34 has a length corresponding to the longitudinal direction of the inspection region to be illuminated, and constitutes a cylindrical lens having a characteristic for irradiating the inspection region with the light of the light emitting diode 33 including the light emission surface 36. To do. In addition, the light incident surface 37 facing the emission surface 36 is a flat surface, and a groove 38 is formed so as to be equal to the cross-sectional shape of the front surface of the light emitting portion 35 of the plurality of light emitting diodes 33. The plurality of light emitting diodes 33 are attached while positioning each light emitting portion 35 by fitting into the groove 38 of the optical element 34, and are fixed by an adhesive or the like (not shown). Although FIG. 1 shows the case where five light emitting diodes 33 are used, the number of light emitting diodes 33 is not limited to this, and an arbitrary number corresponding to a necessary inspection region can be used. The exit surface 36 has a spherical curvature.

  According to such a configuration, the plurality of light emitting diodes 33 can be positioned at a predetermined mounting angle simply by being fitted into the groove 38 of the optical element 34. In addition, since the light emitting diode 33 can be mounted at an accurate angle, useless irradiation light due to variations in the mounting angle is eliminated, and the lighting device 32 with high efficiency and good uniformity can be easily assembled and manufactured. In addition, since a cylindrical lens is used, there is no lens step like a Fresnel lens, and no scattered light is generated, so that there is no reduction in efficiency.

  FIG. 2 shows an optical path of the illumination device 32 according to the first embodiment. In the YZ plane, the optical elements 34 are aligned at an accurate mounting angle by the grooves 38. However, in the first embodiment, spherical aberration is generated by the exit surface 36, and the light collection efficiency is slightly reduced.

  Next, a modification of the first embodiment will be described. In the modification, the spherical aberration is improved by making the exit surface 36 of the optical element 34 an aspherical surface that focuses light on the illuminated position, that is, the inspection region. Other configurations are the same as those of the first embodiment described above. The optical path of the illuminating device 32 which concerns on this modification is shown in FIG. On the YZ plane, the diffusion of light in the Y direction is less than that in FIG. 2, and the light collection efficiency is improved.

  FIG. 4 is a schematic diagram showing the illumination device 32 of the inspection apparatus 1 according to the second embodiment of the present invention. In the optical element 34, the exit surface 36 is an aspherical surface focused on the illuminated position, that is, the inspection region. It was. This is the same as the modification of the first embodiment described above. Further, the light incident surface 37 facing the emission surface 36 is a flat surface, and a plurality of holes 39 are formed in the incident surface 37 so as to be equal to the front shape of the light emitting portions 35 of the light emitting diodes 33. . The plurality of light emitting diodes 33 are attached while positioning the respective light emitting portions 35 by fitting into the holes 39 of the optical element 34, and are fixed by an adhesive or the like (not shown). The configuration other than this point is the same as that of the first embodiment described above.

  According to the second embodiment, the positioning of the light-emitting diodes 33 is carried out by being inserted into the holes 39 corresponding to the individual light-emitting diodes 33, so that the light-emitting diodes 33 are arranged in the row direction, that is, in the longitudinal direction of the optical element 34. Since there is no deviation, the light emitting diode 33 can be positioned and mounted at a more accurate mounting angle, there is no useless irradiation light due to variations in the mounting angle, and the illumination device 32 has high efficiency and good uniformity. Can be easily assembled and manufactured. FIG. 5 shows an optical path of the illumination device 32 according to the second embodiment. Illumination is uniform over a wide range in the X direction.

  FIG. 6 is a diagram showing the illuminance distribution of the lighting devices of these embodiments. FIG. 6 (A) is a first embodiment, FIG. 6 (B) is a modification of the first embodiment, and FIG. ) Is the respective illuminance distribution of the second embodiment. In FIG. 6C, the illuminance distribution of the second embodiment is not uniform because the central portion has a high mountain shape, but actually, since many light emitting diodes 33 are used, this mountain has a longitudinal direction (X direction). ) And can be used as practically good uniform illumination.

  In the second embodiment, the exit surface 36 of the optical element 34 is an aspherical surface that focuses light to the illuminated position. However, the exit surface 36 may be a spherical surface. In addition, when the inspection object is a long object, for example, a printed material on a flexible printed circuit board or a long paper, a structure in which the inspection object is unwound and moved by a winding device while being supported by a roller or the like. It can also be taken.

DESCRIPTION OF SYMBOLS 1 Inspection apparatus 2 Stage 3 Inspection head 4 Moving mechanism 31 Imaging apparatus 32 Illumination apparatus 33 Light emitting diode 34 Optical element 35 Light emission part 36 Outgoing surface 37 Incident surface 38 Groove 39 Hole

Claims (6)

A plurality of light emitting diodes having a light emitting portion formed of a light transmissive material;
An optical element in which a groove corresponding to the shape of the light emitting portion of the plurality of light emitting diodes is formed on one surface, and an emission surface for emitting light is formed on the other surface;
An illumination device, wherein the light emitting diodes are positioned by inserting the light emitting portions of the plurality of light emitting diodes into the long groove. A plurality of light emitting diodes having a light emitting portion formed of a light transmissive material;
An optical element in which a plurality of insertion holes corresponding to the shape of the light emitting portion of the plurality of light emitting diodes are formed side by side and an emission surface that emits light is formed on the other surface;
An illumination device, wherein the light emitting diodes are positioned by inserting the light emitting portions of the plurality of light emitting diodes into the plurality of insertion holes. The lighting device according to claim 1 or 2,
An illumination device characterized in that the exit surface of the optical element is a cylindrical lens that substantially condenses light at an illuminated position. The lighting device according to claim 3.
An illumination apparatus, wherein the exit surface of the cylindrical lens is a spherical surface that is substantially condensed at an illuminated position. The lighting device according to claim 3.
An illumination device, wherein the exit surface of the cylindrical lens is an aspherical surface that substantially condenses light at an illuminated position. A support device for supporting the inspection object;
In the inspection object supported by the support device, an imaging device that images a long inspection region in one direction;
A moving mechanism for relatively moving the inspection object supported by the support device and the imaging device in a direction orthogonal to the longitudinal direction of the inspection region;
The illumination device according to any one of claims 1 to 4, arranged to illuminate the inspection region that is long in the one direction on the surface of the inspection object,
An inspection apparatus comprising:

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