JP2013113858A - Imaging apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imaging apparatus which allows the whole area of an imaging visual field to be uniformly illuminated with a relatively small number of light sources.SOLUTION: An illumination unit 8 includes a lens body 22, a reflector body 24, and a substrate 10c mounted with a plurality of LEDs 26. The lens body 22 has a first surface 22a on the side of the substrate 10c, on which a toroidal lens 28 is arranged corresponding to each of the LEDs 26. The LED 26 has an optical axis LA which is offset outward in the radial direction relative to the center of the toroidal lens 28. The illumination light emitted from the toroidal lens 28 is formed in a rectangular illumination range La defined by a proximal imaging visual field region Ss1 and a distal imaging visual field region Ss2 with an effective working distance WD. The light emitted from each of the illumination unit 8 has a rectangular illumination range La defined by a side which is one of the proximal imaging visual field region Ss1 distal from the LED 26 and a side which is one of the distal imaging visual field region Ss2 proximal to the LED 26.

Description

  The present invention relates to an imaging apparatus.

  An imaging device including a light source for illumination is known. Patent Document 1 relates to a visual sensor, and proposes to integrate a camera and an LED lighting apparatus, which have been separated until then. Patent Document 2 discloses an imaging apparatus in which an LED substrate is disposed at the front end of a lens holder of a camera, and a number of LEDs are disposed on the LED substrate. This type of imaging apparatus is used as an FA sensor for factory equipment, for example. For example, an imaging device is used to inspect inspection objects (workpieces) that flow one after another on a belt conveyor.

  In general, an imaging device detects a workpiece by pattern search or the like within an imaging field, and since the detection position of the workpiece changes every moment, not only the central portion of the imaging field region but also imaging. It is required to uniformly illuminate the entire field of view with a sufficient amount of light.

  As best understood from FIGS. 8, 17, and 18 of Patent Document 2 above, a number of LEDs are installed on the LED substrate installed in the imaging apparatus. The light of each of the many LEDs overlaps with each other in the imaging visual field region, so that the entire imaging visual field region can be illuminated uniformly.

Japanese Patent Laid-Open No. 10-320538 JP 2007-214682 A

  Needless to say, if many LEDs are installed, the cost increases accordingly. For this reason, it is a technical problem to uniformly illuminate the entire imaging visual field region with a small number of LEDs. On the other hand, although it is possible to arrange | position a diffuser plate ahead of each LED, since the diffuser plate has low light transmittance, the problem that the light quantity in an imaging visual field area | region reduces occurs.

  An object of the present invention is to provide an imaging apparatus that can capture an image while uniformly illuminating the entire imaging field area even with a relatively small number of light sources.

The above technical problem is, according to the first aspect of the present invention,
An imaging device including a plurality of light sources for illumination around an imaging unit including a camera and a lens,
An assembly of an illumination lens body and a reflector positioned in front of the light source;
The assembly includes an illumination molding unit that molds light emitted from each light source to form a rectangular illumination region that is substantially the same as the rectangular imaging field of view of the imaging device;
The illumination shaping unit defines light emitted from each light source by one side far from the light source in the imaging field region proximal to the effective working distance of the imaging device and one side near the light source in the distal imaging field region. This is achieved by providing an imaging device characterized by forming a rectangular illumination range.

  According to the invention of the first aspect, the illumination range of each of the plurality of light sources covers the entire region of the imaging visual field proximal and distal of the effective working distance of the imaging device, and the corresponding rectangular shape. Since the shape is defined, it is possible to uniformly illuminate the imaging visual field region while eliminating waste of light from each light source.

The above technical problem is, according to the second aspect of the present invention,
An imaging unit for imaging an inspection object;
A plurality of light sources arranged around the imaging unit for illuminating the inspection object,
A substantially rectangular first imaging field of view that can be imaged by the imaging unit is formed at a position spaced apart from the imaging unit by a first predetermined distance in the optical axis direction of the imaging unit, and the first predetermined distance A substantially rectangular second imaging field of view having a larger area than the first imaging field of view that can be imaged by the imaging unit is formed at a position further separated in the optical axis direction of the imaging unit, and the light of the imaging unit An imaging allowable region in which the imaging unit is in focus is formed between the first imaging visual field region and the second imaging visual field region in the axial direction, and the inspection object located in the imaging allowable region is imaged. An imaging device for imaging by a unit,
An illumination shaping unit that is positioned in front of the light source and forms a light that is emitted from the light source to form a substantially rectangular illumination region that is substantially the same as the imaging field of view of the imaging unit;
In the first imaging field area, the illumination shaping unit has a side far from the light source in the imaging field, and a side near the light source in the imaging field in the second imaging field area. An imaging device characterized by forming a substantially rectangular illumination area as defined on the basis of the above.

  According to the invention of the second aspect, when the inspection object passes between the first imaging field area and the second imaging field area, the imaging field area including the inspection object is illuminated uniformly. be able to.

  Other objects and operational effects of the present invention will become apparent from the detailed description of the embodiments below.

It is the exploded perspective view of the imaging device of the 1st example, and is the figure seen from the slanting back. It is the exploded perspective view of the imaging device of the 1st example, and is the figure seen from the slanting front. It is a front view of the lens main body of the illumination unit contained in the imaging device of an Example. It is sectional drawing which cut | disconnected the illumination unit along the diameter. It is a figure for demonstrating the assembly of a lens main body and a reflector main body regarding the assembly procedure of an illumination unit, Comprising: It is the figure seen from the lens main body side. FIG. 6 is a view corresponding to FIG. 5 and seen from the reflector body side. It is a figure for demonstrating the process of uniting the assembly of a lens main body and a reflector main body with an LED board regarding the assembly procedure of an illumination unit, and it is the figure seen from the assembly side of a lens main body and a reflector main body. It is a figure corresponding to FIG. 7, Comprising: It is the figure seen from the LED board side. It is a figure for demonstrating the process of fixing an illumination unit in a case. It is a figure for demonstrating the method to fix an illumination unit to a case with a screw corresponding to FIG. It is a figure for demonstrating the design of the illumination unit in consideration of the effective working distance of the imaging device of an Example. It is a figure for demonstrating the relationship between the effective working distance of the imaging device of an Example, and illumination. It is a perspective view from the slanting front of the lens body included in an example. FIG. 14 is a view corresponding to FIG. 13, and is a perspective view of the lens body from obliquely rearward. It is a figure corresponding to FIG. 13, FIG. 14, Comprising: It is a side view of a lens main body. It is the perspective view which looked at the lens body of the 1st modification from diagonally forward. FIG. 17 is a view corresponding to FIG. 16, and is a perspective view of the lens body of the first modified example viewed obliquely from the rear. It is a figure corresponding to FIG. 16, FIG. 17, Comprising: It is a side view of the lens main body of a 1st modification. It is the perspective view which looked at the lens body of the 2nd modification from diagonally back. FIG. 20 is a view corresponding to FIG. 19, and is a perspective view of a lens body of a second modified example viewed obliquely from the front. It is a figure corresponding to FIG. 19, FIG. 20, Comprising: It is a side view of the lens main body of a 2nd modification. It is the disassembled perspective view which looked at the illumination unit contained in the imaging device of 2nd Example from diagonally forward. It is a fragmentary sectional view of the illumination unit of FIG. It is a front view of the lens main body contained in the illumination unit of the imaging device of 2nd Example. It is sectional drawing which cut | disconnected the illumination unit of the imaging device of 2nd Example along the diameter. It is a figure for demonstrating the design standard regarding the illumination of the imaging device of 2nd Example. It is a fragmentary sectional view of the part enclosed with the broken line of FIG.

  Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

First Example (FIGS. 1 to 18) :
1 and 2 are exploded perspective views of the image pickup apparatus according to the embodiment. FIG. 1 is a diagram of the imaging device viewed from an oblique rear side, and FIG. 2 is a diagram of the imaging device viewed from an oblique front side. With reference to FIGS. 1 and 2, an imaging apparatus 100 according to the embodiment includes a CMOS camera unit 4 and a lens unit 6 including an end member 2, an illumination unit 8, a plurality of substrates 10, and a front end stop ring 12. Have. Among the plurality of substrates 10, the power supply substrate 10 a (FIG. 2) and the control substrate 10 b are arranged in an L shape on the two side surfaces of the CMOS camera unit 4 and the lens unit 6. A first connector 14 (FIG. 2) is fixed to the front end edge of the power supply board 10a so as to face the front from the lens unit 6. The first connector 14 is located in front of the front end surface of the lens unit 6 and this. Is located adjacent to

  In FIG. 1, reference numeral 10c indicates an LED substrate. The LED board 10c constitutes the rear end face of the illumination unit 8, and the second connector 18 is fixed on the rear face (lens unit 6 side) of the LED board 10c. The second connector 18 is positioned at a position corresponding to the first connector 14 described above.

  The case 16 of the imaging apparatus 100 constitutes a case that surrounds the CMOS camera unit 4 and the lens unit 6 on the rear side. The case 16 also constitutes a case for the lighting unit 6 that houses the lighting unit 6 at its front end.

  The imaging device 100 can be assembled as follows. The case 16 will be mainly described. The CMOS camera unit 4 and the lens unit 6 positioned adjacent to and in front of the unit 16 are inserted on the rear end side of the unit 16, and the illumination unit 8 is mounted on the front end of the case 16. Thus, the imaging device 100 can be assembled by screwing the end member 2 and the front end retaining ring 12 to the case 16. 1 and 2, reference numeral 20 is a screw insertion hole provided in the case 16, and by inserting a screw (not shown) into the screw insertion hole 20, the end member 2 and the front end retaining ring 12 described above. These are screwed to the case 16 while performing relative positioning. In addition, the first and second connectors 14 and 18 are connected to each other as a result of this assembling work, whereby the LED board 10c of the lighting unit 8 is electrically connected to the power supply board 10a, and the power supply board 10a. And connected to the control board 10b.

  The above-described imaging apparatus 100 in FIGS. 1 and 2 operates the illumination unit 8 to image the inspection target while illuminating the imaging visual field region, executes image processing of the imaging data, and outputs the result. .

  FIG. 3 is a front view of the lighting unit 8, and FIG. 4 is a cross-sectional view of the lighting unit 8 cut along the diameter. The illumination unit 8 has a circular outline in plan view, and is made up of three components: an illumination lens body 22, a reflector body 24, and the LED substrate 10 c described above, and the lens body 22 from the front to the rear. The reflector body 24 and the LED substrate 10c are positioned in this order (FIG. 4).

  On the LED substrate 10c having a circular ring shape, four LEDs 26 are positioned at equal intervals in the circumferential direction without obstructing the field of view of the CMOS camera included in the CMOS camera unit 4 (see FIG. 7). The lens body 22 for illumination has a first surface 22a on the LED 26 side and a second surface 22b on the opposite side, that is, the inspection target side. In this embodiment, the first and second surfaces A toroidal lens 28 is formed on both of the surfaces 22a and 22b, and the toroidal lens 28 is disposed at a position corresponding to the LED 26. That is, four toroidal lenses 28 are formed at equal intervals in the circumferential direction on each of the first and second surfaces 22a and 22b, and each toroidal lens 28 is positioned at a position corresponding to the four LEDs 26 on the LED substrate 10c. . Details of the toroidal lens 28 will be described later.

  The reflector body 24 described above is disposed between the lens body 22 and the LED substrate 10c. The reflector body 24 has four openings 36 that are equally spaced in the circumferential direction, and each opening 36 penetrates in the thickness direction of the reflector body 24. The four openings 36 are positioned corresponding to the four LEDs 26 mounted on the LED substrate 10c. The rear end of each opening 36 is open to the LED 26 side, while the front end of the opening 36 is open to the lens body 22 side (FIG. 4). The opening 36 has a mortar shape that gradually expands from the LED 26 toward the lens body 22, and a peripheral wall 36 a of the opening 36 is formed of a reflective surface. Details of the opening 36 will be described later.

  The assembly process of the illumination unit 8 will be described with reference to FIGS. FIG. 5 is an exploded perspective view of the lens body 22 and the reflector body 24 as viewed from the lens body 22 side, and FIG. 6 is an exploded perspective view corresponding to FIG. 5 as viewed from the reflector body 24 side. With reference to FIGS. 5 and 6, the lens body 22 has a circular ring shape and has two first through holes 40 spaced in the diametrical direction on the outer peripheral edge thereof. Further, at least one positioning pin 44 (FIG. 6) standing rearward is formed on the rear surface of the lens body 22, that is, the first surface 22a.

  A screw hole 50 is formed in the reflector body 24 at a position corresponding to the first through hole 40 of the lens body 22. A positioning hole 54 for receiving the positioning pin 44 of the lens body 22 is formed (FIG. 5).

  When the lens body 22 and the reflector body 24 are assembled, the relative rotation positions of the lens body 22 and the reflector body 24 are defined by the positioning pins 44 and the positioning holes 54 that receive the positioning pins 44. Next, the lens body 22 and the reflector body 24 are fixed by a screw 46 (FIG. 5) inserted into the first through hole 40 of the lens body 22, and the lens body 22 and the reflector body 24 are integrated.

  An appropriate distance between the lens body 22 and the reflector body 24 can be easily ensured by the following means. That is, the reflector body 24 is formed with a pedestal 48 that is raised between the openings 36 and 36 adjacent to each other (FIG. 5). By defining the height of the pedestal 48, the lens body 22 and the reflector body An appropriate separation distance from 24 is ensured.

  7 and 8 are views for explaining the assembly of the lens body 22 and the reflector body 24 and the LED substrate 10c. 7 is an exploded perspective view seen from the lens body 22 side, and FIG. 8 is an exploded perspective view corresponding to FIG. 7 seen from the reflector body 24 side. Referring to FIG. 8, the LED board 10c has three screw insertion holes 56 and at least one positioning hole 58 that are spaced apart in the circumferential direction on the outer peripheral portion. On the other hand, on the rear surface of the reflector body 24, screw holes 60 are formed at positions corresponding to the three screw insertion holes 56 of the LED board 10c (FIG. 8), and also correspond to the positioning holes 58 of the LED board 10c. A positioning pin 62 protruding rearward is formed at the position.

  By inserting the positioning pin 62 of the reflector body 24 into the positioning hole 58 of the LED substrate 10c with respect to the assembly of the lens body 22 and the reflector body 24 described with reference to FIGS. 5 and 6, the lens body 22 and The relative rotational position of the LED substrate 10c can be positioned with respect to the assembly of the reflector body 24. By this positioning, the three screw insertion holes 56 of the LED board 10 and the screw holes 60 of the reflector main body 24 are aligned, and the screws 64 are inserted into the screw insertion holes 56 from the LED board 10c side, and the screws 64 are inserted into the reflector main body. The LED board 10c is fixed to the assembly of the lens body 22 and the reflector body 24 by screwing into the 24 screw holes 60, whereby the illumination unit 8 is completed.

  Next, the process of fixing the illumination unit 8 to the case 16 will be described (FIGS. 9 and 10). The illumination unit 8 has two positioning grooves 70 (FIGS. 8 and 9) on the side surface extending in the circumferential direction, and the two positioning grooves 70 are straight across the lens body 22, the reflector body 24, and the LED substrate 10c. It extends to. A recess 72 extending in a ring shape in the circumferential direction opened forward is formed at the front end of the case 16 schematically shown in FIG. 9, and the illumination unit 8 is accommodated in the recess 72. In the recess 72, projections 74 that are received in the two positioning grooves 70 of the illumination unit 8 are formed. The illumination unit 8 is inserted into the recess 72 of the case 16 and the illumination unit 8 is positioned in the recess 72 of the case 16 by engaging the projection 74 of the recess 72 and the two positioning grooves 70 of the illumination unit 8. Can do.

  Here, reference numeral 38 shown in FIG. 9 and the like indicates a lens barrel. The lens barrel 38 is formed at the center of the front end portion of the case 16, and the reflected light in the imaging visual field region is guided to the lens unit 6 and the CMOS camera unit 4 through the lens barrel 38. The recess 72 is formed around the lens barrel 38. The illumination unit 8 has a central opening 8a, and the illumination unit 8 is positioned with the lens barrel 38 passing through the central opening 8a.

  With continued reference to FIG. 9, the lighting unit 8 is formed with three additional longitudinal grooves 76 that are spaced apart in the circumferential direction, and a pedestal 75 is formed in the case 16 correspondingly. The additional vertical groove 76 extends over the lens body 22, the reflector main body 24, and the LED board 10c, but the notch 78 of the LED board 10c corresponding to the additional vertical groove 76 is relatively narrow. (FIG. 10), two edges 78a (only one edge appears in FIG. 10 for drawing reasons) opposed to the width direction of the notch 78 of the LED substrate 10c constitutes the receiving part of the screw head. doing. That is, after positioning the lighting unit 8 in the recess 72 of the case 16, three screws 80 are inserted along the additional vertical groove 76 of the lighting unit 8, and the screws 80 are connected to the top surface of the base 75. When the screw 80 is screwed into the screw hole 75a, the head of the screw 80 is seated on the edge of the notch 78 of the LED board 10c, so that the illumination unit 8 is fixed by the pedestal 75 while being separated from the bottom surface of the case 16. 7 and 9, the illustration of the screw 46 that connects the lens body 22 and the reflector body 24 is omitted.

  FIG. 11 illustrates the spread of light emitted by one of the four LEDs 26 included in the imaging apparatus 100 of the embodiment for the sake of explanation. It should be noted that the light spread of the LED 26 is a rectangular cross section. In order to shape the spread of the light of the LED 26 into a cross-sectional rectangle, in the embodiment, the toroidal lenses 28 of the lens body 22 have different vertical and horizontal curvatures, thereby matching the rectangular imaging field area Ss. The illumination area La is formed. In addition to this, the opening 36 of the reflector 24 has a substantially rectangular cross-sectional shape, thereby increasing the light collection rate with respect to the illumination area having a rectangular cross-section.

  Further, each toroidal lens 28 positioned corresponding to the four LEDs 26 has a curvature corresponding to a relative position with respect to the rectangular imaging field of view, and the curvatures of all the toroidal lenses 28 are not the same. Further, the center O of each toroidal lens 28 is offset toward the imaging field area with respect to the optical axis LA of the LED 26 corresponding thereto (FIG. 4), and the light exiting the toroidal lens 28 is inclined toward the imaging field area side. It is set to illuminate. In addition, as best understood from FIG. 4, each LED 26 installed on the LED board 10 c is positioned so as to approach the outer peripheral edge of the LED board 10 c, and the light is obliquely incident on the toroidal lens 28 from the LED 26. Has been. In relation to this, the wall 36a of the opening 36 of the reflector body 24 is formed by an inclined surface in which a portion located on the outer peripheral side of the reflector body 24 is raised, and a portion located on the center side of the reflector body 24 is It is composed of an inclined surface having a large inclination angle (FIG. 4).

  Still referring to FIG. 11, reference numeral WD indicates an effective working distance WD of the imaging apparatus 100, reference numeral Ss1 indicates a near imaging field area, and reference symbol Ss2 indicates a far imaging field area. Show. The light emitted from each LED 26 is shaped into illumination light having a rectangular cross section by the illumination unit 8 as described above, and as illustrated in FIG. 11. It is defined at the right end of the proximal imaging field region Ss1 with respect to the LED 26 located, that is, one side far from the toroidal lens 28 corresponding to the LED 26, and the left edge of the distal imaging field region Ss2 or the toroidal lens 28 corresponding to the LED 26. The lighting unit 8 is designed so as to be defined on one side close to.

  In other words, a substantially rectangular imaging visual field region Ss1 is formed at a position separated from the CMOS camera unit 4 in the optical axis direction (height direction in FIG. 11) of the CMOS camera unit 4, and from the imaging visual field region Ss1. A substantially rectangular imaging field area Ss2 is formed at a position further apart in the optical axis direction of the CMOS camera unit 4. As a matter of course, since the imaging field area Ss2 is farther from the CMOS camera unit 4 than the imaging field area Ss1, the imaging field area Ss2 is wider than the imaging field area Ss1, and the area of the imaging field area Ss2 is the imaging field area. It becomes larger than the area of Ss1. Then, the inspection object passes between the imaging visual field region Ss1 and the imaging visual field region Ss2. It can be said that the effective working distance is between the imaging visual field region Ss1 and the imaging visual field region Ss2. In other words, when determining the quality of the inspection object, if the distance (working distance) between the CMOS camera unit 4 and the inspection object is within the effective working distance, the visual inspection is performed without being out of focus and with uniform illumination. It can be carried out. Therefore, the effective working distance may be a distance range in which the focus (focus position) of the CMOS camera unit 4 is matched, or may be a distance range in which uniform illumination is performed by the plurality of LEDs 26. In other words, when the inspection object deviates from the effective working distance, that is, when the inspection object (work) is closer to the CMOS camera unit 4 than the imaging field area Ss1, or the inspection object is from the imaging field area Ss2. If the CMOS camera unit 4 is far from the CMOS camera unit 4, the focus of the CMOS camera unit 4 may not be achieved, or the illumination by the LED 26 may be relatively non-uniform, and the uniform illumination within the allowable range in the specification of the imaging apparatus 100 I can't say that.

  Here, when the illumination unit 8 forms a substantially rectangular illumination area, the illumination range by the LED 26 is defined based on a side far from the LED 26 in the imaging field area Ss1 and a side near the LED 26 in the imaging field area Ss2. That is, in FIG. 11, when the light emitted from the illumination unit 8 reaches the same plane as the imaging visual field region Ss1, the right end of the illumination range (when the vertical line is dropped from the illumination unit 8 among the four sides forming the illumination range) Is substantially the same as the right end of the imaging visual field region Ss1 (the one of the four sides forming the imaging visual field region Ss1 that has the longest vertical when the vertical is dropped from the illumination unit 8). (The right end of the imaging field area Ss1 substantially overlaps the right end of the illumination range). In FIG. 11, for convenience of explanation, the right end is not completely matched, but may be completely matched. Of course, there may be some errors.

  In addition, in FIG. 11, when the light emitted from the illumination unit 8 reaches the same plane as the imaging visual field region Ss2, the left end of the illumination range (of the four sides forming the illumination range, the light emitted from the illumination unit 8 is The left side of the imaging field area Ss2 (one of the four sides forming the imaging field area Ss2) is the illumination unit 8 that is opposite to or opposite to one side of the illumination range specified when reaching the same plane as the imaging field area Ss1. Substantially coincides with one side of the imaging field area specified when the light field reaches the same plane as the imaging field area Ss2 (the left edge of the imaging field area Ss1 is the left edge of the illumination range) Almost overlap). In FIG. 11, for convenience of explanation, the left end is not completely matched, but may be completely matched. Of course, there may be some errors.

  In other words, the illumination range by the illumination unit 8 is substantially rectangular, and two opposite sides of the four sides forming the illumination range are defined as specific sides forming the two imaging visual field regions Ss1 and Ss2, respectively. The position is defined by In other words, the irradiation angle range by the illumination unit 8 is defined by the positions of specific sides that form the two imaging visual field regions Ss1 and Ss2, respectively. That is, when the illumination range of the CMOS camera unit 4 is away from the illumination unit 8 in the optical axis direction and the illumination range of the illumination unit 8 includes the entire imaging field of view of the CMOS camera unit 4, this The imaging field-of-view region at that time is defined as an imaging field-of-view region Ss1. At this time, the illumination range and a specific side (right end) of the imaging visual field region Ss1 substantially coincide (substantially overlap). Then, the CMOS camera unit 4 is again moved away from the illumination unit 8 in the optical axis direction, and among the four sides forming the illumination range by the illumination unit 8, one side facing the specific one side or the opposite side (left end) ) Substantially coincides with or substantially overlaps one side (left end) of the imaging visual field region, the imaging visual field region at this time is defined as the imaging visual field region Ss2 (see FIG. 11).

  In other words, the imaging field area (imaging field plane) Ss1 and the imaging field area which are at positions separated (different) in the optical axis direction of the CMOS camera unit 4 and substantially orthogonal to the optical axis of the CMOS camera unit 4 (Imaging field plane) From each of Ss2, in order to define the illumination range or illumination angle range (directivity angle range) by the illumination unit 8, the offset direction of the LED 26 (and the illumination unit 8) with respect to the CMOS camera unit 4 (in FIG. 11) In other words, position information (position in a three-dimensional space) of two sides in a direction substantially orthogonal to the right and left direction is specified, and an illumination range or an illumination angle range by the LED 26 is defined based on these position information. Thereby, the illumination in the space between the imaging visual field region Ss1 and the imaging visual field region Ss2 can be made uniform, and when an inspection object is placed in this space, the inspection accuracy of the appearance inspection can be increased.

  FIG. 12 shows an illumination area La generated by the four LEDs 26 and the illumination unit 8 included in the imaging apparatus 100 of the embodiment and formed into a rectangular cross section. Illumination light traveling obliquely toward the imaging field area Ss from each LED 26 through the illumination unit 8 passes through the illumination area La having a rectangular cross section defined by the proximal imaging field area Ss1 and the distal imaging field area Ss2. Thus, the light of each LED 26 illuminates the entire region of the proximal imaging field region Ss1 and the distal imaging field region Ss2. Accordingly, all the LEDs 26 overlap each other in the entire region of the proximal imaging field region Ss1 and the entire region of the distal imaging field region Ss2, so that uniform illumination is ensured in the effective working distance WD of the imaging device 100. be able to.

  13 to 15 show the lens body 22 described above. 13 is a perspective view of the lens body 22 as viewed from the inspection object side, FIG. 14 is a perspective view of the lens body 22 as viewed from the LED substrate 10c side, and FIG. 15 is a side view of the lens body 22. As described above, the lens body 22 included in the embodiment has the toroidal lens 28 formed on both surfaces 22a and 22b.

  16 to 18 show a first modification 22A of the lens body 22. 16 is a perspective view of a modified lens body 22A viewed from the inspection object side, FIG. 17 is a perspective view of the modified lens body 22A viewed from the LED substrate 10c side, and FIG. 18 is a modified lens. It is a side view of the main body 22A. As can be seen from these drawings, the lens body 22A of the first modification has a toroidal lens 22Fr formed only on the second surface 22b, that is, the surface on the inspection object side.

  19 to 21 show a second modification 22B of the lens body 22. FIG. 19 is a perspective view of the lens body 22B of the second modified example viewed from the inspection object side, FIG. 20 is a perspective view of the lens body 22B of the second modified example viewed from the LED substrate 10c side, and FIG. It is a side view of lens body 22B of the 2nd modification. As can be seen from these drawings, the lens body 22B of the second modification has a toroidal lens 22Fr formed only on the first surface 22a, that is, the surface on the LED substrate 10c side.

  The lens main bodies 22A and 22B of the first and second modified examples shown in FIGS. 16 to 21 described above are defined by the edge of one side of the proximal imaging field region Ss1, and An illumination area La defined by the other edge of the imaging visual field area Ss2 can be set (FIG. 11).

Second Example (FIGS. 22 to 27) :
The basic configuration of the second embodiment is substantially the same as that of the first embodiment described above, and there is a difference in the lighting unit 8. The lighting unit 8 included in the second embodiment will be described below.

  With reference to FIG. 22, the illumination unit 8 includes a lens body 22, a reflector body 24, and an LED substrate 10 c as in the first embodiment.

  Six LEDs 26 are positioned at substantially equal intervals in the circumferential direction on the circular ring-shaped LED substrate 10c. In the embodiment, the LED 26 is composed of an infrared LED having a center electrode 26a (FIG. 22). This infrared LED 26 can be said to be a surface light source having a rectangular shape in plan view and extending in a direction crossing the optical axis. Instead of the infrared LED 26 having the center electrode 26a, an LED that can be employed in the first embodiment without the center electrode 26a may be used.

  FIG. 24 is a front view of the lens body 22. On the second surface 22 b on the inspection object side of the lens body 22, six circular eye fly-eye lens regions 82 are formed at positions corresponding to the LEDs 22, and each fly-eye lens region 82 includes a number of lens elements 84. A lens array 86 is used. Each lens element 84 has a rectangular shape in plan view. Referring to FIG. 23, six circular contour Fresnel surface regions 88 are formed at positions corresponding to the LEDs 22 on the first surface 22 a on the LED 26 side of the lens body 22.

  Six openings 36 of the reflector body 24 located between the lens body 22 and the LED substrate 10 c are provided corresponding to the LEDs 26.

  FIG. 25 is a cross-sectional view of the illumination unit 8 cut along the diameter, and the arrows in FIGS. 26 and 27 indicate the optical path along which the light emitted from the LED 26 travels. FIG. 27 is a diagram in which a portion surrounded by a broken line in FIG. 26 is extracted. 25 and 27, the axis of the opening 36 of the reflector main body 24 and the axes of the Fresnel surface region 88 and the fly-eye lens region 82 of the lens main body 22 are at an angle θ with respect to the vertical line of the LED substrate 10c. It is designed to be inclined toward the imaging region, and in this embodiment, the angle θ is 2 °.

  As can be seen best from FIG. 27, the light emitted from the LED 26 passes through the lens body 22 as parallel light by the Fresnel surface region 88 constituting the first surface 22a of the lens body 22, and the second surface. Scattered by the fly-eye lens region 82 constituting 22b. As described above, since the Fresnel surface area 88 and the fly-eye lens area 82 are inclined and positioned, a rectangular bundle of light from the rectangular lens elements 84 in the fly-eye lens area 82 is captured in the imaging field area Ss (FIG. 11 and FIG. 12). And since the imaging visual field area | region is irradiated in the state where the bundle of rectangular light of the adjacent lens element 84 mutually overlaps, in the imaging visual field area | region, it becomes a uniform light quantity over the whole region. In the embodiment, the light that has passed through the plurality of fly-eye lens regions 82 overlaps in the imaging visual field region, so that uniform illumination in the imaging visual field region is ensured. Therefore, even if the infrared LED 26 having the center electrode 26a is used, uniform illumination in the imaging visual field region can be ensured.

  The effective working distance WD of the image pickup apparatus of the second embodiment is several hundred mm to several thousand mm. Returning to FIG. 24, each lens element 84 formed in the six fly-eye lens regions 82 of the lens body 22 has a rectangular shape that is partitioned by vertical and horizontal boundary lines parallel to each other. Please pay attention to. The vertical and horizontal boundary lines that define the rectangular lens element 84 are parallel to the vertical and horizontal lines that define the rectangular imaging region of the imaging apparatus.

  Each lens element 84 belonging to each fly-eye lens region 82 of the lens body 22 emits rectangular light, and each fly-eye lens region 82 is irradiated with a bundle of rectangular light emitted from a plurality of lens elements 84 belonging thereto. The Each fly-eye lens area 82 has a near imaging field area S1 having an effective working distance WD of several hundred mm and a far imaging field area S2 having an effective working distance WD several thousand mm. Designed to put in. This point will be described with reference to FIG. 26. The fly-eye lens region 82L located on the left side of FIG. 26 captures the right end and the far end of the imaging field region Ss1 whose irradiation range is near. It is designed to be defined at the left end of the visual field area Ss2. On the other hand, the fly eye lens region 82R on the right side of FIG. 26 is defined by one side far from the left end of the imaging field region Ss1 whose irradiation range is near, that is, the fly eye lens region 82R on the right side of the imaging field region Ss1. It is designed to be defined by one side close to the right end of the far-field imaging field region Ss2, that is, the fly-eye lens region 82R on the right side of the imaging field region Ss1. This rule is the same for the other fly-eye lens regions 82 of the lens body 22.

  Therefore, the rectangular light bundles coming out of all the fly-eye lens regions 82 of the lens body 22 not only overlap each other in the rectangular imaging field of view with an effective working distance WD of several hundred mm to several thousand mm, The waste of irradiating the peripheral area other than the imaging visual field area can be rationally eliminated. Therefore, not only can the light emitted from the LED 26 be used for illumination of the imaging field of view area without waste, but also the illumination field of view can be illuminated uniformly without unevenness in the amount of light. Therefore, even if an infrared LED having a center electrode is employed, uniform illumination can be ensured without causing a decrease in the amount of light.

DESCRIPTION OF SYMBOLS 100 Imaging device of Example 4 CMOS camera unit 6 Lens unit 8 Illumination unit 10c LED substrate 16 Case 22 Lens body for illumination 22a First surface on the LED side of the illumination lens body 22b On the inspection object side of the illumination lens body Second surface 24 Reflector body 26 LED
28 Toroidal lens 36 Aperture (reflector body)
38 Lens barrel 72 Recess (accommodates lens body and reflector assembly)
LA LED optical axis O Center of toroidal lens Ss Imaging field area La Illumination area WD Effective working distance Ss1 Near imaging field area Ss2 Far imaging field area 82 Fly eye lens area 84 Lens element 86 Lens array 88 Fresnel surface area

Claims (16)

An imaging device including a plurality of light sources for illumination around an imaging unit including a camera and a lens,
An assembly of an illumination lens body and a reflector positioned in front of the light source;
The assembly includes an illumination molding unit that molds light emitted from each light source to form a rectangular illumination region that is substantially the same as the rectangular imaging field of view of the imaging device;
The illumination shaping unit defines light emitted from each light source by one side far from the light source in the imaging field region proximal to the effective working distance of the imaging device and one side near the light source in the distal imaging field region. An imaging device characterized by forming a rectangular illumination range. An imaging unit for imaging an inspection object;
A plurality of light sources arranged around the imaging unit for illuminating the inspection object,
A substantially rectangular first imaging field of view that can be imaged by the imaging unit is formed at a position spaced apart from the imaging unit by a first predetermined distance in the optical axis direction of the imaging unit, and the first predetermined distance A substantially rectangular second imaging field of view having a larger area than the first imaging field of view that can be imaged by the imaging unit is formed at a position further separated in the optical axis direction of the imaging unit, and the light of the imaging unit An imaging allowable region in which the imaging unit is in focus is formed between the first imaging visual field region and the second imaging visual field region in the axial direction, and the inspection object located in the imaging allowable region is imaged. An imaging device for imaging by a unit,
An illumination shaping unit that is positioned in front of the light source and forms a light that is emitted from the light source to form a substantially rectangular illumination region that is substantially the same as the imaging field of view of the imaging unit;
In the first imaging field area, the illumination shaping unit has a side far from the light source in the imaging field, and a side near the light source in the imaging field in the second imaging field area. An imaging device characterized by forming a substantially rectangular illumination area as defined on the basis of the above.   The upper limit position and the lower limit position of the imaging allowable region in the optical axis direction of the imaging unit are substantially the same as the positions of the first imaging visual field region and the second imaging visual field region in the optical axis direction of the imaging unit. The imaging device according to claim 2, wherein The substantially rectangular illumination region formed by the illumination shaping unit includes a first side located in front of the light source, a second side substantially orthogonal to and adjacent to the first side, and the second side. A third side adjacent to the side and facing the first side,
The illumination range by the light source is defined based on the third side in the first imaging visual field region and the first side in the second imaging visual field region. The imaging device described in 1.   The illumination shaping unit forms a substantially rectangular illumination region so that an illumination range by the light source overlaps the entire imaging field in the first imaging field region and the second imaging field region. 5. The imaging device according to any one of 4.   The rectangular illumination region formed by the illumination shaping unit is located at a position where the first side is spaced outward from the imaging field in the first imaging field region, and in the second imaging field region The imaging apparatus according to any one of claims 2 to 4, wherein the third side is located away from the imaging field of view.   The rectangular illumination region formed by the illumination shaping unit has the second side substantially overlaps the side of the imaging field in the first imaging field region and the second imaging field region. The imaging device according to any one of 2 to 4. The light source is composed of at least a first pair and a second pair of light sources located across the optical axis of the imaging unit,
The illumination molding part is composed of a lens positioned corresponding to each light source,
The imaging device according to claim 1 or 2, wherein a curvature of a lens corresponding to each of the first pair of light sources is different from a curvature of a lens corresponding to each of the second pair of light sources. A light source substrate on which the plurality of light sources are arranged;
The imaging device according to claim 1, wherein the illumination molding unit is configured by an assembly including an illumination lens body and a reflector positioned in front of each light source disposed on the light source substrate. An assembly comprising the illumination lens body and the reflector has a central hole therethrough,
The imaging apparatus has a case that houses an assembly including the illumination lens body and a reflector,
The case is provided with a ring-shaped recess opened forward around a lens barrel extending in the center, and the assembly including the illumination lens body and the reflector is accommodated in the recess,
The imaging device according to claim 9, wherein reflected light of an imaging visual field region is guided to the imaging unit through the lens barrel.   The imaging device according to claim 1, wherein the light source is an LED.   The imaging device according to claim 1 or 10, wherein the illumination lens body includes a toroidal lens at a position corresponding to the light source, and the toroidal lens forms part of the illumination molding unit.   The imaging device according to claim 12, wherein a center of the toroidal lens is offset toward a center of the assembly with respect to an optical axis of the light source corresponding to the toroidal lens.   The reflector has a mortar-shaped opening that gradually expands from the light source side toward the lens body side, and the wall on the center side of the assembly of the opening is relatively larger than the outer wall. The imaging device according to claim 10, wherein the imaging device is inclined. The illumination lens body has a fly-eye lens at a position corresponding to the light source,
The imaging apparatus according to claim 1, wherein the fly-eye lens is configured by a lens array including a plurality of rectangular lens elements. The fly-eye lens is formed on the surface on the inspection object side of the illumination lens body, the Fresnel surface corresponding to the fly-eye lens is formed on the light source side surface of the illumination lens body,
The imaging apparatus according to claim 15, wherein the fly-eye lens and the Fresnel surface constitute a part of the illumination molding unit.

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